October 7

Humanity Sees the Other Side of the Moon

1959 — Luna 3 Photographs the Far Side of the Moon

First photograph: 03:30 UTC

On October 7, 1959, humanity saw a landscape that had remained hidden throughout all previous human history. It was the other side of the Moon. At 03:30 UTC, the Soviet spacecraft Luna 3 began photographing the lunar far side. The accomplishment was remarkable not simply because of the distance involved, but because of a fundamental characteristic of the Moon's motion. The Moon rotates on its axis. But it takes approximately the same amount of time to rotate once as it takes to orbit Earth once. This condition, called synchronous rotation, causes nearly the same lunar hemisphere always to face Earth. Small oscillations known as libration allow observers to see somewhat more than half of the lunar surface over time. But a large portion of the Moon remained permanently hidden from direct observation on Earth. Generations of astronomers could map craters, mountains, and dark volcanic plains on the familiar lunar face. No telescope, regardless of its power, could look around the Moon and show what lay beyond its edge. To see the far side, humanity would have to send a camera there. Luna 3 did exactly that. The spacecraft had launched on October 4 and swept past the Moon's southern polar region on October 6. Its trajectory then carried it behind the Moon and outward, placing its cameras in position to look back at the illuminated far hemisphere. At 03:30 UTC on October 7, from a distance of roughly 63,500 kilometers from the lunar surface, the photographic sequence began. Over approximately 40 minutes, Luna 3 exposed 29 photographs. Together they covered about 70 percent of the Moon's far side. Taking the pictures was only the first challenge. There were no digital cameras. Luna 3 used photographic film. The spacecraft therefore contained an automated miniature photographic laboratory. After exposure, the film was chemically developed, fixed, dried, and then scanned electronically. The resulting image information could be transmitted toward Earth by radio. It was, in effect, a photographic laboratory and long-distance image transmitter traveling through deep space. Seventeen usable photographs were eventually received on Earth. By modern standards, they were poor. They were grainy. Contrast was limited. Fine surface details were difficult to distinguish. But their scientific importance did not depend upon photographic beauty. For the first time, human beings could see enough of the hidden hemisphere to recognize its large-scale geography. And the far side contained a surprise. It looked different. The familiar Earth-facing hemisphere contains enormous dark regions known as maria—ancient impact basins later flooded by basaltic lava. These broad plains create many of the patterns people have imagined as a “Man in the Moon.” The far side showed far fewer large maria. Instead, much of it appeared bright, rugged, mountainous, and densely cratered. Among the features visible in Luna 3's photographs was a dark region later named Mare Moscoviense—the Sea of Moscow. Other features received names as astronomers began constructing the first maps of the newly revealed hemisphere. Later lunar spacecraft would greatly improve upon Luna 3. Zond probes photographed additional territory. American Lunar Orbiter spacecraft mapped potential Apollo landing regions and other portions of the Moon. Apollo astronauts saw the far side directly as they traveled around the Moon. Modern spacecraft such as the Lunar Reconnaissance Orbiter have mapped the entire lunar surface at resolutions Luna 3's engineers could scarcely have imagined. Those later observations revealed one of the solar system's largest impact structures—the enormous South Pole-Aitken basin—spanning much of the lunar far side. Scientists also came to understand why the two hemispheres differ so strongly. The Moon's crust is generally thicker on the far side. On the near side, enormous ancient impacts penetrated more deeply and were followed by extensive volcanic flooding, producing the dark maria visible from Earth. The far side experienced a different geological history. But before scientists could explain that difference, they first had to discover it. Luna 3 provided the first glimpse. The achievement becomes even more remarkable when placed in chronological perspective. Only two years and three days earlier, Sputnik 1 had become the world's first artificial satellite. Now a spacecraft had traveled to the Moon, passed behind it, automatically photographed an unseen world, developed the pictures onboard, and begun the process of returning those images across hundreds of thousands of kilometers of space. The Space Age was barely two years old. Already, humanity had seen beyond the horizon of another world. Why It Matters: Luna 3's photographs gave humanity its first view of the Moon's far side and revealed that the two lunar hemispheres are strikingly different. The mission transformed an entire hemisphere from an unknowable region into a place that could be photographed, mapped, named, and scientifically investigated. It also demonstrated sophisticated deep-space navigation, automatic photography, onboard film processing, and long-distance image transmission at the very beginning of the Space Age.

 

Also on This Day

2008 — Asteroid 2008 TC3 Strikes Earth Exactly Where Astronomers Predicted

Atmospheric entry approximately 02:46 UTC

Before dawn on October 7, 2008, a small asteroid entered Earth's atmosphere over northern Sudan. Such events are not unusual. Small objects from space enter the atmosphere regularly, most burning up harmlessly before reaching the ground. This event was different. Astronomers knew it was coming. For the first time, an asteroid had been discovered in space before an Earth impact and its arrival time and location successfully predicted. The story began only about 20 hours earlier. At 06:39 UTC on October 6, astronomer Richard Kowalski, working with the Catalina Sky Survey's 1.5-meter telescope on Mount Lemmon in Arizona, detected a rapidly moving object. The observations were sent to the Minor Planet Center. Orbital calculations quickly produced an extraordinary conclusion. The object was on a collision course with Earth. It received the designation 2008 TC3. The asteroid was tiny by planetary-defense standards—only a few meters across. It posed no serious threat to people on the ground. But scientifically, it presented an unprecedented opportunity. Observatories around the world began tracking it. During the hours before impact, professional and amateur astronomers supplied hundreds of positional measurements, allowing scientists to refine the asteroid's trajectory. NASA's Jet Propulsion Laboratory calculated that it would enter Earth's atmosphere above northern Sudan at approximately 02:46 UTC on October 7. And it did. The asteroid struck the atmosphere at roughly 12.8 kilometers per second. At high altitude above the Nubian Desert, it exploded in a brilliant fireball. For a time, scientists thought the object might have been completely destroyed. Then came another remarkable development. Meteor astronomer Peter Jenniskens joined Muawia Shaddad of the University of Khartoum and Sudanese students and researchers to search the predicted fall area. They found meteorites. Eventually, hundreds of fragments were recovered from the Nubian Desert. The meteorites became known collectively as Almahata Sitta, Arabic for “Station Six,” after a nearby railway stop. Scientists could now do something unprecedented. They had astronomical observations of an asteroid while it was still in space. They also possessed physical pieces of that same asteroid in laboratories on Earth. The connection between asteroid astronomy and meteorite science had become direct. Analysis revealed that 2008 TC3 was compositionally unusual, containing a diverse mixture of materials associated with a rare meteorite type known as ureilites. The event also demonstrated the rapidly improving capabilities of near-Earth-object surveys. A small asteroid had been found only hours before impact, yet the international astronomical community had been able to determine where and when it would arrive. Larger hazardous asteroids are generally detectable at much greater distances, potentially providing far more warning. Why It Matters: 2008 TC3 was the first asteroid discovered and tracked in space before its impact with Earth was successfully predicted. The subsequent recovery of meteorites linked telescopic observations of a specific asteroid directly with laboratory samples, while the accurate impact forecast demonstrated an important capability for modern planetary defense.

 

The Bigger Picture

October 7 brings together two events separated by nearly half a century. At first they seem unrelated. Luna 3 looked outward toward the Moon. Astronomers tracking 2008 TC3 looked for something coming toward Earth. But both events depended upon the same fundamental ability: predict where an object in space is going to be. Luna 3 could photograph the far side only because engineers understood its trajectory well enough to send it around the Moon and place it in the correct position at the correct time. 2008 TC3 could be predicted to strike northern Sudan because astronomers measured its position repeatedly and calculated its future path. This is celestial mechanics transformed into practical capability. For centuries, astronomers used mathematics to predict where planets would appear in the sky. During the Space Age, those same principles acquired new purposes. They allowed us to send spacecraft toward other worlds. And increasingly, they allow us to identify objects that might come toward ours. The two events also represent different forms of discovery. Luna 3 discovered by seeing something for the first time. 2008 TC3 demonstrated discovery through prediction. Scientists did not merely watch the asteroid appear as a fireball and then reconstruct what had happened. They saw it coming. That distinction is fundamental to planetary defense. Finding an asteroid after it passes Earth tells us about the population of near-Earth objects. Finding one before an encounter gives us options. For an object only a few meters across, as 2008 TC3 was, the appropriate response is observation. For a substantially larger asteroid discovered sufficiently far in advance, the possibilities could eventually include deflection. That is the same planetary-defense story we encountered on September 26 with DART. DART demonstrated that humanity can deliberately change the motion of an asteroid. 2008 TC3 demonstrated another essential part of the equation: first, we must find it and determine where it is going. October 7 therefore spans two very different frontiers. In 1959, an entire hemisphere of the Moon lay beyond human sight. In 2008, astronomers detected a tiny object in the darkness of space and predicted where it would meet Earth. One expanded the world we could see. The other expanded our ability to anticipate what might reach us. Both began by looking carefully into the sky.

At a Glance

1959 — 03:30 UTC — Luna 3 begins photographing the Moon's far side from roughly 63,500 kilometers above the lunar surface, giving humanity its first views of a hemisphere that had never before been seen.

2008 — Approximately 02:46 UTC — Asteroid 2008 TC3 enters Earth's atmosphere over northern Sudan at the location and time astronomers had predicted, becoming the first asteroid discovered before impact whose collision with Earth was successfully forecast.

October 6

A Planet Around Another Sun

1995 — Astronomers Announce the Discovery of 51 Pegasi b

Time not applicable

On October 6, 1995, two Swiss astronomers announced a discovery that changed humanity's understanding of planetary systems. Michel Mayor and Didier Queloz had detected a planet orbiting 51 Pegasi, an ordinary Sun-like star approximately 50 light-years from Earth. The planet became known as 51 Pegasi b. It was the first planet discovered orbiting a main-sequence star similar to the Sun. Astronomers had wondered about planets around other stars for centuries. Were the planets of our solar system unusual? Or did other stars have worlds of their own? Claims of extrasolar planets had appeared before, but many collapsed under further observation. By the early 1990s, astronomers had discovered planets orbiting a pulsar—the dense remnant of an exploded star—but no planet had yet been reliably detected around an ordinary Sun-like star. Mayor and Queloz were searching for such worlds at the Observatoire de Haute-Provence in southern France. They were not trying to photograph planets directly. Instead, they measured the motion of stars. A planet does not simply orbit a motionless star. Both planet and star orbit their common center of mass. Because a star is vastly more massive, its motion is small. But sufficiently precise spectroscopy can detect the star moving slightly toward and away from Earth. As the star approaches, features in its spectrum shift slightly toward shorter, bluer wavelengths. As it recedes, they shift toward longer, redder wavelengths. This is the radial-velocity method. Mayor and Queloz used an advanced spectrograph called ELODIE to measure those tiny changes. The observations of 51 Pegasi revealed a regular pattern. The star was wobbling. And the wobble repeated approximately every 4.23 days. The most convincing explanation was a planet. But the inferred planet was astonishing. 51 Pegasi b had at least roughly half the mass of Jupiter, yet it orbited its star at only about one-twentieth the Earth-Sun distance. A year on the planet lasted just over four Earth days. Nothing like it existed in our solar system. Mercury, our innermost planet, requires 88 days to orbit the Sun. Jupiter takes nearly twelve years. Planet-formation models of the period generally expected giant planets to form far from their stars, where temperatures were low enough for abundant solid material and ices to contribute to the formation of massive planetary cores. Yet here appeared to be a Jupiter-like planet almost touching its star by comparison. The discovery initially seemed so surprising that skepticism was understandable. But independent observations soon confirmed the signal. A new category of planet entered the astronomical vocabulary: the hot Jupiter. The discovery also forced astronomers to reconsider how planetary systems form and evolve. Perhaps giant planets could form farther from their stars and then migrate inward, their orbits altered through interactions with the disks of gas and dust surrounding young stars or through later gravitational interactions with other planets. If planetary systems could change dramatically after formation, then our own solar system represented only one possible architecture among many. The importance of the discovery extended much farther than one strange planet. Once astronomers knew that planets around ordinary stars could be detected, searches accelerated. New instruments achieved greater precision. Transit surveys watched for the tiny dimming produced when planets crossed in front of their stars. Space telescopes such as Kepler discovered thousands of planetary candidates. Other observatories studied planetary atmospheres. Astronomers found super-Earths, mini-Neptunes, hot Jupiters, compact multiplanet systems, circumbinary planets orbiting two stars, and worlds occupying environments unlike anything represented in our solar system. The question gradually changed. Astronomers no longer asked simply: Do other stars have planets? They began asking: What kinds of planets exist, how do planetary systems form, and how common are worlds that might support life? In 2019, the Nobel Prize in Physics recognized Mayor and Queloz for the discovery of an exoplanet orbiting a solar-type star. 51 Pegasi b was later given the official name Dimidium. The planet itself is unlikely to resemble anything habitable. Its importance lies elsewhere. It revealed that the galaxy contains planetary systems that nature assembled in ways astronomers had scarcely imagined.

Why It Matters: The discovery of 51 Pegasi b opened the modern era of exoplanet astronomy. It provided the first confirmed planet around a Sun-like main-sequence star, challenged existing ideas about planetary formation, and helped transform the search for other worlds from speculation into one of astronomy's most productive fields.

 

Also on This Day

1959 — Luna 3 Sweeps Past the Moon

Closest-approach time not established

Two days after its October 4 launch, the Soviet spacecraft Luna 3 reached the Moon on October 6, 1959. Its journey had a purpose no previous spacecraft had accomplished. Luna 3 was preparing to show humanity a part of the Moon that no human being had ever seen. Because the Moon rotates once in approximately the same time it takes to orbit Earth, nearly the same lunar hemisphere always faces us. The opposite hemisphere—the lunar far side—remained largely hidden. Luna 3's trajectory carried it past the Moon's southern polar region at an altitude of approximately 7,900 kilometers, then around behind the Moon. The flyby itself was crucial. The spacecraft's looping trajectory would place it in the correct geometry to photograph the far side after closest approach. The historic photography occurred the following day, October 7. From tens of thousands of kilometers away, Luna 3 exposed 29 photographs of the previously unseen hemisphere. The spacecraft then developed the photographic film automatically, scanned the images, and transmitted them toward Earth by radio. The pictures were crude. But for the first time, humanity could see the Moon as a complete world rather than only as the familiar face presented to Earth. The images revealed a major geological surprise. The far side contained far fewer of the broad dark volcanic plains—the maria—that dominate much of the near side. Later lunar missions would map that hemisphere with vastly greater precision. But those explorations began with Luna 3's passage around the Moon on October 6.

Why It Matters: Luna 3's October 6 flyby positioned the spacecraft for humanity's first photography of the Moon's far side the following day. The mission turned a permanently hidden hemisphere from an astronomical unknown into an observable landscape.

1990 — Ulysses Launches to Explore the Sun from a New Direction

11:47:16 UTC

On October 6, 1990, Space Shuttle Discovery lifted off from Kennedy Space Center carrying five astronauts and an unusual spacecraft named Ulysses. Its destination was the Sun. But Ulysses would not travel directly toward it. Instead, it would first go to Jupiter. At 11:47:16 UTC, Discovery began mission STS-41. The crew consisted of commander Richard Richards, pilot Robert Cabana, and mission specialists William Shepherd, Bruce Melnick, and Thomas Akers. The principal payload in Discovery's cargo bay was a joint mission of the European Space Agency and NASA. Scientists understood that most planetary exploration took place near a broad plane surrounding the Sun called the ecliptic. Earth and the major planets orbit relatively close to this plane. Consequently, spacecraft launched from Earth naturally begin their journeys within it. That created a problem for solar science. Scientists wanted to study the environment over the Sun's north and south poles. No rocket available could simply launch Ulysses directly into the steeply inclined solar orbit required. Mission designers found a more elegant solution. They would use Jupiter's gravity. About six hours after Discovery reached orbit, the crew deployed Ulysses from the Shuttle's payload bay. A powerful combination of upper stages then accelerated the spacecraft away from Earth. At the time, Ulysses departed Earth faster than any previous human-made spacecraft. It traveled outward across the solar system rather than inward toward the Sun. In February 1992, Ulysses reached Jupiter. The spacecraft passed the giant planet, and Jupiter's gravity dramatically bent its trajectory. Instead of continuing near the ecliptic, Ulysses was thrown into an orbit carrying it far above and below the plane in which the planets travel. The solar poles had become accessible. Ulysses made its first passage over the Sun's southern polar region in 1994 and its first northern polar passage in 1995. The spacecraft did not photograph the Sun in the way a conventional telescope might. Instead, its instruments sampled the solar wind, magnetic fields, energetic particles, cosmic rays, interstellar dust, and other components of the heliosphere. For the first time, scientists could examine the Sun's environment in three dimensions rather than primarily from near the ecliptic plane. Ulysses discovered that the solar wind emerging from high solar latitudes behaved differently from the slower, more variable wind found nearer the solar equator. It investigated how the Sun's magnetic field changes during the solar cycle. It studied cosmic rays entering the heliosphere. And by accident, it made an extraordinary cometary discovery. In 1996, Ulysses unexpectedly encountered the ion tail of Comet Hyakutake, even though the spacecraft was hundreds of millions of kilometers from the comet's nucleus. The encounter revealed that cometary tails could extend much farther through space than previously appreciated. Ulysses had originally been designed for a mission lasting about five years. Instead, it operated for more than 18 years, completing nearly three circuits of the Sun. Operations finally ended in 2009.

Why It Matters: Ulysses was the first mission to investigate the space environment above and below the Sun's poles. By using Jupiter's gravity to leave the ecliptic plane, it gave scientists their first broad three-dimensional survey of the heliosphere and demonstrated once again how celestial mechanics can make possible journeys that rocket power alone cannot easily accomplish.

 

The Bigger Picture

October 6 asks us to reconsider something that seems familiar. The Moon is familiar. The Sun is familiar. Other stars are familiar. But familiarity can conceal how incomplete our knowledge really is. For almost all of human history, people could see only one general hemisphere of the Moon. Luna 3 changed that. Astronomers had observed the Sun for centuries, and spacecraft had been studying it since the beginning of the Space Age. But nearly all those observations were made from close to the plane in which Earth and the other planets orbit. Ulysses changed the perspective. Then came 51 Pegasi b. The planets of our solar system had provided humanity's only detailed example of how a planetary system was organized. There were small rocky planets close to the Sun. Giant planets lived farther away. That arrangement seemed natural. Then astronomers found a giant planet racing around its star every four days. Once again, nature was telling us: the view from where we happen to stand is not the whole story. This is one of astronomy's most persistent lessons. We see the universe from one location. Earth. We inhabit one planetary system. The solar system. We orbit one ordinary star. The Sun. From that limited sample, it is remarkably easy to assume that what surrounds us is typical. Exploration repeatedly breaks that assumption. Travel behind the Moon, and its two hemispheres look surprisingly different. Leave the ecliptic, and the Sun's environment looks different from above its poles. Examine other stars closely enough, and planetary systems appear whose architecture would once have seemed almost impossible. October 6 therefore represents one of the deepest purposes of astronomy and space exploration: change the point of view, and the universe changes with it.

At a Glance

1959 — Closest-approach time not established — Luna 3 passes approximately 7,900 kilometers above the Moon's southern polar region and swings behind the Moon, positioning itself to photograph the lunar far side the following day.

1990 — 11:47:16 UTC — Space Shuttle Discovery launches on STS-41 carrying Ulysses, the ESA-NASA spacecraft that will use Jupiter's gravity to become the first mission to explore the space environment above and below the Sun's poles.

1995 — Time not applicable — Michel Mayor and Didier Queloz announce the discovery of 51 Pegasi b, the first confirmed planet found orbiting a Sun-like main-sequence star.

 

October 5

A More Diverse View from Space

1984 — Challenger Launches a Mission of Firsts

11:03:00 UTC

Fifteen minutes before sunrise on October 5, 1984, Space Shuttle Challenger lifted from Kennedy Space Center carrying a crew unlike any that had flown before. There were seven people aboard—at the time, the largest crew ever launched together on a single spacecraft. Two were women. One was Canadian. One was an oceanographer whose principal laboratory for the next eight days would be the view through Challenger's windows. At 11:03:00 UTC, mission STS-41G began. The crew was commanded by veteran astronaut Robert Crippen, making his fourth journey into space. Jon McBride served as pilot. The three mission specialists were David Leestma, Sally Ride, and Kathryn Sullivan. Ride was already historic. In June 1983 she had become the first American woman in space. Now, for the first time, two women would fly together on the same space mission. The crew also included two payload specialists. Paul Scully-Power, an Australian-born American oceanographer, would concentrate much of his work on observing Earth's oceans from orbit. And Marc Garneau represented Canada. When Challenger reached space, Garneau became the first Canadian to travel beyond Earth. His presence also symbolized Canada's increasingly important role in the Space Shuttle program. Canadian engineering had already produced one of the Shuttle's most recognizable pieces of equipment—the Remote Manipulator System, better known as the Canadarm. STS-41G was therefore international in a way that foreshadowed the increasingly multinational character of human spaceflight. But the mission's principal subject was not the people aboard Challenger. It was the planet below them. STS-41G carried an extensive collection of instruments for observing Earth's atmosphere, oceans, land surfaces, and energy balance. Among the most important payloads was the Earth Radiation Budget Satellite—ERBS. Understanding Earth's climate requires understanding energy. Sunlight delivers energy to the planet. Some is reflected back into space by clouds, ice, land, and oceans. Some is absorbed by Earth's surface and atmosphere and later radiated outward as infrared energy. The balance between incoming and outgoing energy is fundamental to Earth's climate. ERBS was designed to measure that balance. Shortly after reaching orbit, Sally Ride used Challenger's Canadarm to lift the satellite from the payload bay. A problem appeared almost immediately. ERBS's solar arrays did not deploy properly. Mission Control suspected that the hinges had become too cold. Ride oriented the satellite toward the Sun and gently moved it with the robotic arm. The arrays opened. ERBS was released and eventually maneuvered into its operational orbit. Designed for a mission of roughly two years, it continued collecting data for more than two decades, contributing to the long-term study of Earth's radiation balance and climate. Challenger itself carried additional Earth-observation instruments. Radar examined portions of Earth's surface. Cameras recorded landscapes and atmospheric phenomena. Scully-Power concentrated on ocean structures visible from orbit—eddies, currents, waves, and other patterns that could reveal processes difficult to appreciate from ships or aircraft. The human eye itself had become a scientific instrument. Another historic moment came later in the mission. On October 11, Kathryn Sullivan and David Leestma left Challenger's cabin for an extravehicular activity lasting about three and a half hours. Sullivan thereby became the first American woman to walk in space. Their principal task was not ceremonial. They demonstrated equipment for transferring fluids in orbit—technology relevant to the possibility of refueling spacecraft and satellites in space. STS-41G therefore combined several different kinds of progress. It advanced Earth science. It tested technology. It expanded international participation. And its crew visibly broadened the group of people participating directly in human spaceflight. After more than eight days and 132 completed orbits, Challenger returned to Kennedy Space Center on October 13. It was only the second Shuttle mission to land there.

Why It Matters: STS-41G brought together several important developments in human spaceflight. It carried the first two women to fly together in space, made Marc Garneau the first Canadian in space, and later enabled Kathryn Sullivan to become the first American woman to perform a spacewalk. Just as importantly, the mission demonstrated the growing value of spaceflight for studying Earth itself, deploying a satellite and operating instruments that helped scientists investigate the planet's atmosphere, oceans, surface, and energy balance.

 

Also on This Day

1967 — Astronaut Clifton Williams Dies in a Training Accident

Time not established

On October 5, 1967, NASA astronaut and Marine Corps Major Clifton C. “C.C.” Williams Jr. died when the T-38 jet he was flying crashed near Tallahassee, Florida. He was 35 years old. Williams had joined NASA's third group of astronauts in 1963. Like many members of the early astronaut corps, he was an accomplished military test pilot. He had graduated from the U.S. Naval Test Pilot School and accumulated approximately 2,500 hours of flying time, most of it in jet aircraft. At NASA, Williams served as backup pilot for Gemini 10 and worked on launch operations and crew safety. He was also part of the developing Apollo program. Williams had been assigned to the backup crew for an early Apollo mission and was expected to remain within the rotation that could eventually lead to a lunar flight. On October 5, he was flying from Florida toward Houston in a NASA T-38. A mechanical failure led to a loss of control. Williams ejected, but he was traveling too fast and was too low for the escape to save him. His death came during an already painful year for the American space program. Only months earlier, on January 27, astronauts Gus Grissom, Ed White, and Roger Chaffee had died in the Apollo 1 fire during a launch-pad test. Williams became another astronaut lost before he could fly in space. His place in the astronaut rotation was taken by Alan Bean. Bean later served as lunar module pilot of Apollo 12 and became the fourth human being to walk on the Moon. Williams was not forgotten by the crew. Apollo 12 commander Pete Conrad, who had served with Williams on the Gemini 10 backup crew, arranged for Williams's naval aviator wings to travel to the Moon. The insignia was left on the lunar surface in November 1969. Williams's name also appears on the Space Mirror Memorial at Kennedy Space Center, which honors astronauts who died while serving the American space program.

Why It Matters: Clifton Williams's death reminds us that the risks of human spaceflight extend beyond launches and missions. The astronaut corps depended upon constant aircraft training, testing, simulation, and preparation, all of which carried dangers of their own. Williams never reached space, but he was part of the generation whose work and sacrifice helped prepare the way for Apollo.

 

The Bigger Picture

October 5 is fundamentally about who participates in exploration—and what exploration is for. Clifton Williams belonged to the early astronaut corps, an organization drawn largely from a narrow population of American military test pilots. There were reasons for that. Early spacecraft were experimental vehicles, and test pilots possessed precisely the combination of engineering knowledge, flying skill, physical conditioning, and experience with dangerous machinery that NASA needed. But human spaceflight did not remain within that original model. STS-41G makes the change visible. Sally Ride was a physicist. Kathryn Sullivan was a geologist. Paul Scully-Power was an oceanographer. Marc Garneau was a Canadian engineer and naval officer. The Shuttle was becoming not merely a spacecraft piloted by astronauts but a working platform capable of carrying scientists, engineers, international partners, and specialists whose expertise lay outside traditional test piloting. That transition mattered because the purpose of going into space was changing as well. STS-41G spent much of its time looking down. The crew observed oceans. Radar mapped land. Instruments studied the atmosphere. ERBS measured the flow of energy into and out of the Earth system. This is one of the great recurring themes of the Space Age. Humanity went into space partly because we wanted to explore what lies beyond Earth. But once we arrived there, we discovered a remarkable new place from which to understand Earth itself. Weather satellites changed forecasting. Earth-observation spacecraft transformed geology, agriculture, oceanography, mapping, disaster response, and environmental science. Long-term measurements from orbit became essential to understanding climate. The view outward and the view homeward became complementary parts of the same enterprise. There is also a human progression visible between 1967 and 1984. Williams trained during an era when only a handful of nations had sent people into space. Seventeen years later, Challenger carried the first Canadian astronaut. Two women traveled together aboard the same spacecraft. A scientist specializing in Earth's oceans could look directly at those oceans from orbit. Exploration was becoming broader—not only in where humanity could go, but in who could participate and what questions they could ask once they arrived.

At a Glance

1967 — Time not established — NASA astronaut Clifton C. Williams Jr. dies in a T-38 training accident near Tallahassee, Florida; his place in the Apollo crew rotation will later be filled by future Moonwalker Alan Bean.

1984 — 11:03:00 UTC — Space Shuttle Challenger launches on STS-41G with a record seven-person crew, including Sally Ride and Kathryn Sullivan—the first two women to fly together in space—and Marc Garneau, the first Canadian in space.

October 4

The Space Age Begins

1957 — Sputnik 1 Becomes the World's First Artificial Satellite

19:28:34 UTC

On October 4, 1957, a rocket rose from a launch site in the Soviet republic of Kazakhstan carrying a polished metal sphere only 58 centimeters—about 23 inches—across. At 19:28:34 UTC, the Soviet Union launched Sputnik 1, the world's first artificial satellite. Humanity had entered the Space Age. Sputnik itself was remarkably simple. The pressurized aluminum sphere weighed approximately 83.6 kilograms, or 184 pounds. Four long antennas extended behind it, and two radio transmitters broadcast alternating signals at frequencies of approximately 20 and 40 megahertz. Those transmissions produced the feature for which Sputnik became famous: its repeated “beep-beep-beep” radio signal. The sound was technologically simple but historically extraordinary. For the first time, a human-made object was circling Earth and announcing its presence by radio. Sputnik entered an elliptical orbit and completed a circuit of Earth approximately every 96–98 minutes. Anyone with suitable radio equipment could listen. Professional tracking stations heard it. Amateur radio operators heard it. People around the world heard recordings broadcast over radio and television. The signal made something abstract suddenly tangible. Spaceflight was no longer a theoretical possibility. It was happening overhead. The satellite itself also contributed scientific information. The behavior of its radio signals helped researchers study the propagation of radio waves through Earth's ionosphere, while changes in Sputnik's orbit provided information about the density of the upper atmosphere. But Sputnik's greatest effects occurred on Earth. The Soviet Union had demonstrated not only that it could build a satellite but that it possessed a rocket powerful enough to place a substantial object into orbit. That had immediate military implications. A rocket capable of launching a satellite suggested technologies related to those required for an intercontinental ballistic missile. The achievement shocked the United States. American scientists and engineers had also been developing satellite programs for the International Geophysical Year, but none had yet reached orbit. Suddenly, the Soviet Union was first. The psychological impact became known as the “Sputnik crisis.” American political leaders, educators, scientists, and military officials began asking how the Soviet Union had achieved such an important technological first. The response affected education, research, defense, and government organization. Federal support increased for science, mathematics, engineering, and foreign-language education. The Advanced Research Projects Agency—later DARPA—was established in 1958. Most importantly for the history we have been following, Congress passed the National Aeronautics and Space Act, which President Dwight D. Eisenhower signed on July 29, 1958. On October 1, 1958—as we noted only three days ago in this chronology—NASA began operations. Sputnik therefore helped create the circumstances that produced the American civilian space agency. Meanwhile, the satellite continued circling Earth. Its batteries lasted about three weeks. After that, the famous radio signal stopped. But Sputnik itself remained in orbit. Atmospheric drag gradually lowered its trajectory until, on January 4, 1958, after approximately three months and some 1,400 orbits of Earth, Sputnik reentered the atmosphere and burned up. The spacecraft was gone. The age it began was not.

Why It Matters: Sputnik 1 was the first artificial satellite of Earth and is widely regarded as the beginning of the Space Age. Its launch demonstrated that orbital spaceflight was possible, transformed Cold War competition, accelerated investment in science and technology, helped spur the creation of NASA, and began the transition from looking at space to physically entering it.

 

Also on This Day

1959 — Luna 3 Begins Its Journey to the Far Side of the Moon

00:43:40 UTC

Exactly two years after Sputnik 1, the Soviet Union launched another spacecraft from Kazakhstan. Its destination was the Moon. At 00:43:40 UTC on October 4, 1959, Luna 3 began a mission that would reveal something no human being had ever seen: the far side of the Moon. The reason that hemisphere remained hidden was not that the Moon does not rotate. It does. But the Moon rotates once on its axis in approximately the same time it takes to orbit Earth. This synchronous rotation causes nearly the same lunar hemisphere always to face our planet. Small effects called libration allow observers on Earth to glimpse somewhat more than half the lunar surface over time. But a substantial portion remained permanently beyond terrestrial view. For all of human history, people had looked at the Moon without knowing what much of its opposite hemisphere looked like. Luna 3 was designed to change that. The spacecraft weighed approximately 278.5 kilograms and carried the Yenisey-2 photographic television system, along with instruments for studying radiation, charged particles, and micrometeoroids. Its trajectory carried it beyond the Moon and around the lunar far side. On October 6, Luna 3 passed the Moon's southern polar region. Then, on October 7, with the far side illuminated by sunlight, its camera began taking photographs. Over approximately 40 minutes, the spacecraft exposed 29 photographs, covering roughly 70 percent of the previously unseen hemisphere. That alone was an extraordinary achievement. But there was another problem. The photographs were inside a spacecraft hundreds of thousands of kilometers away. Digital imaging did not yet exist. Luna 3 used actual photographic film. The spacecraft therefore carried equipment that automatically developed the film aboard the spacecraft. The resulting images were then scanned electronically and transmitted toward Earth by radio, in a process somewhat analogous to sending a fax across interplanetary space. Seventeen usable images were eventually received. They were poor by modern standards—grainy, noisy, and lacking fine detail. But what they showed was astonishing. The lunar far side looked different from the familiar hemisphere facing Earth. The near side is dominated by broad dark plains called maria, created by ancient volcanic flows that filled enormous impact basins. The far side contained far fewer large maria and appeared more heavily cratered and mountainous. Among the features identified from Luna 3's photographs were Mare Moscoviense, the Sea of Moscow, and the feature initially called Mare Desiderii, the Sea of Dreams. Later spacecraft would photograph the far side in vastly greater detail.

But Luna 3 had done something more fundamental. It had turned an unknown hemisphere into a place humans could see and map. Why It Matters: Luna 3 provided humanity's first photographs of the Moon's far side, revealing that it differed dramatically from the familiar Earth-facing hemisphere. The mission demonstrated sophisticated deep-space navigation, automated photography, onboard film processing, and long-distance image transmission only two years after the beginning of the Space Age.

2004 — SpaceShipOne Wins the Ansari X Prize

Spacecraft release and powered flight began approximately 14:49 UTC

On October 4, 2004—47 years to the day after Sputnik 1—pilot Brian Binnie climbed aboard the small experimental spacecraft SpaceShipOne above California's Mojave Desert. The goal was not orbit. The goal was to demonstrate that a privately developed, reusable crewed spacecraft could reach space twice within two weeks. The challenge had been established by the Ansari X Prize, a $10 million competition intended to encourage development of private human spaceflight. To win, a privately financed vehicle had to reach an altitude of at least 100 kilometers, the internationally recognized Kármán-line boundary commonly used to define the beginning of space, while carrying the equivalent mass of three people. Then it had to do it again within two weeks using the same spacecraft. SpaceShipOne had already completed the first qualifying flight. On September 29, pilot Mike Melvill had flown it to an altitude of approximately 102 kilometers. Five days later came the second attempt. SpaceShipOne did not launch vertically from the ground. Instead, a carrier aircraft called White Knight carried it to an altitude of more than 13 kilometers. At approximately 14:49 UTC, SpaceShipOne separated. Binnie ignited its hybrid rocket motor and accelerated steeply upward. The spacecraft continued climbing after the engine shut down. It reached an altitude of approximately 112 kilometers—nearly 70 miles above Earth. That was comfortably beyond the 100-kilometer requirement. It also exceeded the altitude record for a winged rocket-powered aircraft established by the X-15 four decades earlier. During reentry, SpaceShipOne employed one of its most distinctive innovations. The rear portion of its wings rotated upward into a high-drag “feathered” configuration. Rather than requiring the pilot to maintain a precisely controlled attitude throughout the most difficult portion of reentry, the feathered configuration helped the spacecraft align itself aerodynamically. Once it descended into denser atmosphere, the wings returned to their normal position. SpaceShipOne became a glider. Binnie landed safely back at Mojave. The two qualifying flights had occurred only five days apart. The team had won the $10 million Ansari X Prize. SpaceShipOne did not enter orbit, and it did not immediately produce routine passenger travel into space. Its historical significance was more specific. A privately developed reusable spacecraft had demonstrated repeated crewed suborbital spaceflight without being operated as a government space program. The Smithsonian later placed SpaceShipOne in the National Air and Space Museum alongside such milestones as the Wright Flyer, Charles Lindbergh's Spirit of St. Louis, John Glenn's Friendship 7, and the Bell X-1.

Why It Matters: SpaceShipOne's October 4 flight completed the requirements for the Ansari X Prize and demonstrated that a privately developed reusable crewed spacecraft could make repeated trips beyond the 100-kilometer boundary of space. It became an important milestone in the emergence of commercial human spaceflight.

 

The Bigger Picture

Few dates illustrate the transformation of spaceflight as clearly as October 4. In 1957, Sputnik 1 demonstrated that humanity could place an object into orbit. In 1959, Luna 3 demonstrated that a spacecraft could travel hundreds of thousands of kilometers from Earth, pass behind another world, photograph territory no human had ever seen, process those photographs automatically, and send them home. In 2004, SpaceShipOne demonstrated something different: human spaceflight was beginning to extend beyond the exclusive operation of national governments. The progression is remarkable. Reach space → orbit Earth → explore another world → broaden who can build and operate spacecraft. There is also a striking contrast between Sputnik 1 and Luna 3. Only two years separated them. Sputnik was a radio transmitter inside a metal sphere. Luna 3 was a deep-space robotic observatory equipped to navigate around the Moon, orient itself, photograph an unseen landscape, chemically develop film automatically, scan the results, and transmit the pictures across hundreds of thousands of kilometers. That rapid progression reminds us how quickly the early Space Age developed. The first satellite did not lead to decades of cautious experimentation before humanity ventured farther. Within a year, spacecraft were being aimed toward the Moon. Within two years, one had reached the lunar surface and another had traveled behind it. Within four years, a human being would orbit Earth. And within twelve years of Sputnik, people would walk on the Moon. October 4 also reminds us that anniversaries can influence history. Luna 3 was launched on the second anniversary of Sputnik. SpaceShipOne's prize-winning flight occurred on the 47th anniversary. The United Nations later designated October 4–10 as World Space Week, beginning with the anniversary of Sputnik and ending with the anniversary of the 1967 Outer Space Treaty entering into force. The date therefore became more than the anniversary of one satellite. It became a marker for humanity's entrance into a new realm. Before October 4, 1957, every object ever made by human hands remained on Earth—or returned quickly to it. After that night, there was something else overhead: an object built on Earth, traveling around the world on its own celestial path. The sky had ceased to be only something humanity observed. It had become somewhere humanity could go.

At a Glance

1957 — 19:28:34 UTC — The Soviet Union launches Sputnik 1, the world's first artificial satellite, beginning the Space Age.

1959 — 00:43:40 UTC — Luna 3 launches toward the Moon; three days later it will obtain humanity's first photographs of the lunar far side.

2004 — Approximately 14:49 UTC — Brian Binnie begins SpaceShipOne's second qualifying X Prize spaceflight, reaching approximately 112 kilometers and securing the Ansari X Prize for repeated privately developed crewed suborbital spaceflight.

October 3

The Rocket That Changed the Future

1942 — The A-4 Rocket Makes Its First Successful Flight

Launch time not established

On October 3, 1942, a rocket rose from the German Army research center at Peenemünde on the Baltic coast. Known during development as the A-4, it would later become infamous under another name: V-2. The test vehicle climbed to an altitude of roughly 85–90 kilometers and traveled approximately 190 kilometers before falling back to Earth. It was the first successful flight of a machine unlike anything that had preceded it. The A-4 was a large, long-range, liquid-fueled ballistic rocket. Its engine burned alcohol and liquid oxygen and produced approximately 25 metric tons of thrust. An advanced guidance system controlled the vehicle during powered flight. Previous experimental rockets had demonstrated many of the principles involved. The American physicist Robert Goddard had successfully flown the world's first liquid-fueled rocket in 1926 and subsequently developed increasingly sophisticated rockets incorporating gyroscopic stabilization, pumps, and other technologies. German experimenters had also pursued liquid-fueled rocketry during the 1920s and 1930s. But the A-4 represented a dramatic increase in scale. The October 3 flight demonstrated that a large liquid-fueled rocket could climb to extreme altitude, follow a guided ballistic trajectory, and travel hundreds of kilometers. In purely technological terms, it was a milestone on the road toward spaceflight. But it was not built to explore space. It was built to carry an explosive warhead. Germany was at war, and the A-4 became the V-2, short for Vergeltungswaffe 2—“Vengeance Weapon 2.” Beginning in 1944, V-2 missiles were launched against London, Antwerp, and other targets. Unlike aircraft or earlier weapons, the V-2 descended toward its target at supersonic speed. No warning system could provide meaningful time to intercept it. Thousands of civilians and military personnel were killed or injured by V-2 attacks. Yet even that terrible toll does not encompass the weapon's human cost. Mass production was centered at the underground Mittelwerk factory, where prisoners from the Mittelbau-Dora concentration-camp system were subjected to forced labor under appalling conditions. Thousands died from starvation, disease, exhaustion, beatings, executions, and other abuse. More people died producing the V-2 than were killed by its operational use as a weapon. That history is inseparable from the rocket. After Germany's defeat in 1945, both the United States and Soviet Union sought German rocket hardware, documents, and specialists. The United States brought Wernher von Braun and more than one hundred other German rocket specialists to America through the program eventually known as Operation Paperclip. Captured V-2 rockets were transported to the United States and launched from White Sands, New Mexico, carrying scientific instruments into the upper atmosphere. The Soviet Union similarly obtained German hardware, facilities, documentation, and specialists. Soviet engineers studied and reproduced the technology before developing increasingly capable rockets of their own. The descendants of those programs eventually moved beyond weapons. In the United States, von Braun's team helped develop the Redstone, Jupiter, and Saturn rockets. The Saturn V carried astronauts to the Moon. In the Soviet Union, engineers under Sergei Korolev developed a different technological lineage culminating in the R-7, the rocket family that launched Sputnik and Yuri Gagarin and whose descendants continue to fly. The October 3, 1942, flight therefore occupies an uncomfortable but unavoidable place in space history. The rocket demonstrated technologies that would eventually help humanity reach beyond Earth. But it was created for war, under a dictatorship responsible for enormous crimes, and its later production depended upon murderous exploitation. Both truths belong in the story.

Why It Matters: The successful A-4 flight demonstrated technologies fundamental to later large liquid-fueled rockets and strongly influenced postwar rocket development in both the United States and Soviet Union. But its significance cannot be separated from its origin as a Nazi weapon and from the concentration-camp prisoners who suffered and died producing it. The history of spaceflight contains extraordinary achievements, but understanding that history also requires remembering the human costs embedded within some of its technological foundations.

 

Also on This Day

1962 — Wally Schirra Flies Sigma 7 Six Times Around Earth

Launch: 12:15:12 UTC

On October 3, 1962, astronaut Walter “Wally” Schirra climbed into the small Mercury spacecraft he had named Sigma 7. The name reflected the kind of mission he intended to fly. The Greek letter sigma is used in mathematics to represent summation. For Schirra, Sigma 7 represented the sum of the engineering work that had gone into Mercury—and the seven astronauts originally chosen for the program. At 12:15:12 UTC, an Atlas rocket lifted Sigma 7 from Cape Canaveral. Schirra became the fifth American in space and the third American to orbit Earth. John Glenn and Scott Carpenter had each completed three orbits earlier that year. Schirra would attempt six. The mission, officially designated Mercury-Atlas 8, emphasized engineering and spacecraft operations. One of its most important questions concerned resources. Mercury carried limited electrical power and maneuvering fuel. If future missions were to remain in space longer, astronauts would have to demonstrate that those resources could be conserved. Schirra deliberately allowed Sigma 7 to drift for extended periods rather than continuously controlling its attitude. The technique greatly reduced fuel consumption. He also conducted spacecraft tests, photographed Earth, made visual observations, and experimented with using stars for orientation. At one point Schirra transmitted a television message from orbit, one of the early live broadcasts from an American spacecraft. After six circuits of Earth, he prepared for reentry. His landing demonstrated another aspect of the mission's precision. Sigma 7 splashed down in the Pacific after 9 hours, 13 minutes, and 11 seconds in flight. The spacecraft landed only a few miles from the recovery carrier USS Kearsarge. It was the first crewed American orbital mission to end with a Pacific Ocean splashdown. Schirra later described Sigma 7 as a “textbook flight.” The characterization was appropriate. Mercury was becoming less about proving that an American could survive orbit and more about demonstrating that people and spacecraft could operate there predictably and efficiently. Schirra would later become the only astronaut to fly in all three of America's pioneering human-spaceflight programs: Mercury, Gemini, and Apollo.

Why It Matters: Sigma 7 demonstrated disciplined spacecraft operation, fuel conservation, and precise reentry during America's longest orbital mission to that point. Mercury was evolving from an experiment in human survival into the foundation for the more complex operations required by Gemini and Apollo.

1985 — Atlantis Makes Its First Flight

15:15:30 UTC

On October 3, 1985, another spacecraft began a much longer career. At 15:15:30 UTC, Space Shuttle Atlantis lifted off from Kennedy Space Center on mission STS-51J. It was Atlantis's first journey into space. Atlantis was the fourth operational orbiter constructed for NASA's Space Shuttle fleet, following Columbia, Challenger, and Discovery. Its first mission was unusual because much of what it carried and accomplished was classified. STS-51J was a dedicated mission for the United States Department of Defense. Commander Karol Bobko led a five-person crew consisting of pilot Ronald Grabe and mission specialists David Hilmers, Robert Stewart, and William Pailes. The mission's primary payload involved military communications satellites. Because of the classified nature of the flight, NASA's normal public coverage stopped shortly after Atlantis reached orbit. After four days in space, Atlantis landed at Edwards Air Force Base in California on October 7. Its first mission was complete. But the orbiter's career was only beginning. Atlantis would eventually become one of the most important vehicles in the Shuttle fleet. It launched the Magellan spacecraft toward Venus in 1989. Later that year, it launched Galileo toward Jupiter. In 1991, Atlantis carried the Compton Gamma Ray Observatory, one of NASA's Great Observatories, into orbit. During the 1990s, Atlantis became closely associated with the Shuttle-Mir program, completing multiple dockings with the Russian space station and helping build experience in international long-duration operations. It later played a major role in assembling and servicing the International Space Station. And on July 8, 2011, Atlantis lifted off on STS-135, the final mission of the entire Space Shuttle program. The spacecraft that began its career with a classified military mission on October 3, 1985, therefore ended it almost 26 years later by closing one of the most recognizable chapters in the history of human spaceflight.

Why It Matters: STS-51J began the 33-mission career of Space Shuttle Atlantis. Over the following quarter century, the orbiter would launch major planetary and astronomical spacecraft, help pioneer cooperation with Mir, support construction of the International Space Station, and ultimately fly the final mission of the Space Shuttle era.

 

The Bigger Picture

October 3 offers an unusually concentrated view of the evolution of the rocket. In 1942, the A-4 demonstrated that a large liquid-fueled rocket could travel to extraordinary altitude and range. Twenty years later, an Atlas rocket carried Wally Schirra into orbit. Twenty-three years after that, Atlantis climbed toward space using a combination of reusable liquid-fueled engines and enormous solid rocket boosters. Technologically, it is tempting to draw a simple line: A-4 → ballistic missiles → launch vehicles → human spaceflight → reusable spacecraft. There is truth in that progression. But it is incomplete. Technology does not carry its own moral purpose. A rocket engine can accelerate a warhead toward a city. A related technology can carry a scientific instrument above Earth's atmosphere. Another can place a human being into orbit. Still another can launch a probe toward Jupiter. The physical laws are the same. The purposes are not. That distinction is particularly important on October 3. The people who suffered and died in the V-2 program should not disappear from the history simply because technologies developed there later contributed to space exploration. Nor should the history imply that modern spaceflight emerged from one nation or one group alone. Robert Goddard's pioneering experiments in the United States, Konstantin Tsiolkovsky's theoretical work in Russia, Hermann Oberth's writings and experiments in Europe, Soviet engineering under Sergei Korolev, American research, and contributions from thousands of engineers and scientists across many countries all belong to the much larger story. By the time Schirra flew Sigma 7, the rocket had become a means of placing a human being into orbit. By the time Atlantis flew, rockets had become part of a transportation system capable of carrying people, satellites, observatories, and planetary spacecraft. October 3 therefore gives us something more complicated than a story of technological progress. It asks us to remember that the history of exploration contains both achievement and responsibility. Understanding how we reached space means remembering both.

At a Glance

1942 — Launch time not established — The A-4 makes its first successful test flight from Peenemünde, demonstrating large-scale liquid-fueled ballistic-rocket technology that will strongly influence postwar missile and space-launch development.

1962 — 12:15:12 UTC — Wally Schirra launches aboard Sigma 7 on Mercury-Atlas 8, completing six Earth orbits during a 9-hour, 13-minute engineering mission.

1985 — 15:15:30 UTC — Space Shuttle Atlantis launches on STS-51J for its maiden flight, beginning a 33-mission career that will continue through the final Space Shuttle mission in 2011.

October 2

 The Mathematics of Reaching Other Worlds

1920 — Giuseppe “Bepi” Colombo Is Born

Time unknown

On October 2, 1920, Giuseppe “Bepi” Colombo was born in Padua, Italy. He would become a mathematician and engineer whose insights helped change the way spacecraft travel through the solar system. Colombo studied mathematics at the University of Pisa, graduating in 1944, and later became a professor at the University of Padua. His interests ranged across celestial mechanics, planetary science, spacecraft trajectories, orbital dynamics, and the behavior of artificial satellites. But his name became particularly associated with Mercury. For many years, astronomers believed that Mercury kept essentially the same face toward the Sun, much as the Moon keeps the same face toward Earth. Radar observations in the 1960s demonstrated otherwise. Mercury rotates once approximately every 59 Earth days, while taking about 88 days to orbit the Sun. At first, that relationship seemed peculiar. Colombo recognized its significance. Mercury was locked into a 3:2 spin-orbit resonance: for every two journeys it makes around the Sun, the planet rotates exactly three times. That realization helped explain one of the solar system's more unusual examples of orbital and rotational dynamics. Colombo's most influential contribution to spaceflight emerged as NASA prepared Mariner 10, the first spacecraft intended to visit Mercury. Getting to Mercury is surprisingly difficult. A spacecraft launched from Earth already shares Earth's enormous orbital velocity around the Sun. To reach Mercury, it must lose substantial orbital energy and fall inward toward the Sun without simply racing past its target. Mariner 10's planned trajectory included a flyby of Venus. Colombo recognized something remarkable about the spacecraft's subsequent orbit. If engineers carefully selected the geometry of Mariner 10's encounter with Mercury, the planet's gravity could reshape the spacecraft's orbit around the Sun so that Mariner 10 would return to Mercury again. NASA's Jet Propulsion Laboratory studied the proposal and confirmed it. The idea worked. Mariner 10 flew past Venus in February 1974, using the planet's gravity to alter its trajectory. It encountered Mercury for the first time on March 29, 1974. Then it came back. Mariner 10 flew past Mercury again in September 1974 and a third time in March 1975. Instead of one encounter, scientists received three. The spacecraft photographed a cratered surface that in some respects resembled the Moon, discovered that Mercury possessed an unexpected intrinsic magnetic field, and greatly improved knowledge of the innermost planet. The trajectory represented an important development in the use of gravity assists. The principle is elegant. A spacecraft approaching a moving planet enters the planet's gravitational influence. As the spacecraft swings past, gravity bends its trajectory. Viewed relative to the Sun, the encounter can transfer orbital energy between the planet and spacecraft, changing the spacecraft's speed and direction without requiring the equivalent amount of rocket propellant. The change to the planet's motion is immeasurably small. For the spacecraft, it can be transformative. Gravity assists became one of the essential tools of interplanetary exploration. The Voyagers used planetary encounters to travel through the outer solar system. Galileo used gravity assists at Venus and Earth to reach Jupiter. Cassini used Venus, Earth, and Jupiter on its journey to Saturn. MESSENGER used repeated encounters with Earth, Venus, and Mercury before entering Mercury orbit. The European-Japanese BepiColombo mission takes the concept even farther, combining solar-electric propulsion with multiple planetary flybys to gradually remove enough orbital energy to enter orbit around Mercury. Colombo contributed to other areas as well. He developed ideas involving long orbital tethers and helped inspire ESA's mission to Halley's Comet, suggesting that it be named Giotto after the medieval Italian artist who depicted the Star of Bethlehem in a manner possibly inspired by a comet. Colombo died in 1984, before Giotto encountered Halley's Comet in 1986. His influence continued. In 1999, the European Space Agency named its ambitious Mercury mission BepiColombo in his honor. The joint ESA-JAXA mission would employ precisely the sort of sophisticated orbital mechanics with which Colombo's name had become associated. Why It Matters: Giuseppe Colombo demonstrated how mathematical insight could dramatically expand what a spacecraft could accomplish. His work helped Mariner 10 turn one planned encounter with Mercury into three and contributed to the development of gravity-assist techniques that became fundamental to planetary exploration. His career illustrates a crucial truth about spaceflight: reaching another world depends as much upon understanding celestial mechanics as upon building powerful rockets.

 

Also on This Day

1962 — Explorer 14 Launches to Investigate Earth's Space Environment

Launch time not established

On October 2, 1962, NASA launched Explorer 14, also known during development as S-3a, aboard a Thor-Delta rocket from Cape Canaveral. The spacecraft was designed to investigate an environment that scientists had only recently discovered was far more complicated than expected. Before the Space Age, the region surrounding Earth was sometimes imagined as comparatively empty. The first Explorer satellites changed that picture. Measurements beginning with Explorer 1 in 1958 revealed intense populations of energetic charged particles trapped by Earth's magnetic field—the Van Allen radiation belts. Explorer 14 continued the investigation. Its scientific instruments included detectors for cosmic rays, solar particles, trapped radiation, ions, plasma, and magnetic fields. Its highly elliptical orbit carried it from a few hundred kilometers above Earth to roughly 100,000 kilometers away, allowing instruments to sample very different regions of Earth's magnetic environment. The mission was especially timely. The Sun was capable of releasing streams and eruptions of energetic particles into interplanetary space. When those particles encountered Earth's magnetic field, they could dramatically change conditions around the planet. Understanding that environment was important scientifically, but it also had practical consequences. Astronauts and spacecraft electronics could be exposed to radiation. Radio communications could be disrupted. Satellites would have to operate within an environment shaped simultaneously by Earth and the Sun. Explorer 14 returned roughly 6,500 hours of scientific data during about ten months of useful operation. Among its contributions were observations helping scientists understand the shape of Earth's magnetosphere and the behavior of charged particles within it. The scientific field would eventually become central to what we now call space weather.

Why It Matters: Explorer 14 helped reveal that the space surrounding Earth is not empty but a dynamic environment filled with charged particles and shaped by Earth's magnetic field and the Sun. Understanding that environment became essential both to heliophysics and to the safe operation of spacecraft.

1991 — Soyuz TM-13 Launches an International Crew Toward Mir

Launch time not established

On October 2, 1991, Soyuz TM-13 launched from the Baikonur Cosmodrome carrying a crew that reflected the rapidly changing political geography of Europe and the Soviet Union. Commander Aleksandr Volkov was accompanied by Toktar Aubakirov of Kazakhstan and Franz Viehböck of Austria. Aubakirov became the first Kazakh in space. Viehböck became the first Austrian in space. Their destination was the Soviet space station Mir. The flight occurred at an extraordinary historical moment. Only weeks earlier, an attempted coup against Soviet leader Mikhail Gorbachev had failed. Several Soviet republics were moving rapidly toward independence. The Soviet Union itself had only months left to exist. Aubakirov's presence was therefore especially symbolic. He had been born in the Kazakh Soviet Socialist Republic, while the Baikonur launch complex from which he departed was located on Kazakh territory. Viehböck's mission, meanwhile, grew from Austrian-Soviet scientific cooperation. During his time aboard Mir, he conducted experiments involving medicine, physics, materials, and other fields. Aubakirov and Viehböck remained aboard Mir only briefly before returning to Earth with cosmonaut Anatoly Artsebarsky. Volkov stayed. He joined Sergei Krikalev, who had already been living aboard Mir since May. Then history overtook the mission. In December 1991, the Soviet Union ceased to exist. Volkov and Krikalev had launched under one political system and would return in March 1992 to a transformed world. Baikonur itself was now located in the independent nation of Kazakhstan. The spacecraft continued orbiting Earth while borders, governments, and national identities changed beneath it.

Why It Matters: Soyuz TM-13 expanded human spaceflight to Kazakhstan and Austria while also becoming part of one of the most remarkable political transitions ever experienced during a space mission. Mir continued operating even as the Soviet state that had created it disappeared, demonstrating how spaceflight institutions and international partnerships could survive profound changes on Earth.

 

The Bigger Picture

October 2 reminds us that exploration depends upon learning how to navigate environments that cannot be controlled. For Bepi Colombo, that environment was the gravitational architecture of the solar system. Planets are not simply destinations. They are moving masses whose gravity can become part of the spacecraft itself—a kind of invisible propulsion system available to anyone who can calculate the trajectory precisely enough. Explorer 14 confronted another invisible environment. Earth appears to orbit through empty space, but the planet is actually surrounded by magnetic fields and energetic particles interacting continuously with the Sun. Spacecraft entering that environment must understand it rather than ignore it. And Soyuz TM-13 encountered an environment of another kind. While its crew traveled to Mir, the political world beneath them was changing dramatically. The Soviet Union that launched the mission would soon disappear, yet the station remained in orbit and its crews continued working. There is an intriguing common thread: exploration succeeds by adapting to forces larger than the spacecraft itself. Gravity cannot be switched off. The solar wind cannot be stopped. History on Earth does not pause because people are living in orbit. The explorer therefore learns the environment and works within it. Colombo's great insight made this especially clear. Early thinking about interplanetary flight could easily emphasize rocket power: if another world is difficult to reach, build a more powerful rocket and carry more fuel. Celestial mechanics offers a subtler answer. Sometimes the solar system itself can help. A planet's gravity can accelerate a spacecraft, slow it, redirect it, or arrange another encounter years later. The planets become not merely destinations on the journey. They become part of the road.

At a Glance

1920 — Time unknown — Giuseppe “Bepi” Colombo is born in Padua, Italy; his later work on Mercury and spacecraft trajectories helps establish gravity-assist techniques as an essential tool of planetary exploration.

1962 — Launch time not established — NASA launches Explorer 14 to investigate energetic particles, plasma, cosmic radiation, and Earth's magnetosphere.

1991 — Launch time not established — Soyuz TM-13 launches Aleksandr Volkov, Toktar Aubakirov, and Franz Viehböck toward Mir; Aubakirov and Viehböck become the first people from Kazakhstan and Austria, respectively, to travel in space.

October 1

NASA Opens for Business

1958 — The National Aeronautics and Space Administration Begins Operations

Time not applicable

On October 1, 1958, a new agency of the United States government officially began operations. Its name was the National Aeronautics and Space Administration—NASA. The agency had been created only two months earlier, when President Dwight D. Eisenhower signed the National Aeronautics and Space Act into law on July 29. But October 1 was the day NASA actually opened for business. Its creation had been accelerated by events unfolding high above Earth. On October 4, 1957, the Soviet Union launched Sputnik 1, the world's first artificial satellite. A month later came Sputnik 2, carrying the dog Laika. The United States was suddenly confronted with unmistakable evidence that the Soviet Union possessed powerful rocket technology and had taken the lead in the emerging exploration of space. The American response was not simply to build another rocket. The United States needed an organization capable of coordinating a long-term civilian program of aeronautical and space research. There was already an institution from which to build one. The National Advisory Committee for Aeronautics, or NACA, had been established in 1915. For more than four decades, its engineers and scientists had conducted research that profoundly influenced aircraft design, aerodynamics, propulsion, and high-speed flight. NASA did not replace that expertise so much as inherit and expand it. On September 30, thousands of people left work as NACA employees. On October 1, they returned as NASA employees. Approximately 8,000 NACA personnel formed the core of the new agency. NASA initially inherited three major NACA laboratories—Langley in Virginia, Ames in California, and Lewis in Ohio—along with smaller facilities at Wallops Island, Virginia, and the high-speed flight station at Edwards Air Force Base in California. NASA's first administrator was T. Keith Glennan, formerly president of the Case Institute of Technology. NACA director Hugh L. Dryden, one of America's most respected aeronautical scientists, became NASA's first deputy administrator. The agency's initial headquarters occupied temporary quarters in the Dolley Madison House on Lafayette Square in Washington, D.C. There, on October 1, Glennan addressed a headquarters staff of approximately 170 people. The organization was small compared with the NASA that would emerge during the following decade. But it did not remain small for long. NASA soon absorbed or acquired responsibility for programs and organizations already engaged in space-related work. These included space-science activities associated with the Naval Research Laboratory, the Jet Propulsion Laboratory in California, and eventually the Army rocket-development organization in Huntsville led by Wernher von Braun. Almost immediately, the new agency confronted the question of human spaceflight. On NASA's first day of operation, Robert Gilruth briefed Glennan about plans for sending a person into space. NASA's historical account records that within two hours of hearing the presentation, Glennan told Gilruth to proceed. The effort soon developed into the Space Task Group and Project Mercury. Only ten days after NASA began operations, Pioneer 1 became the first spacecraft launched under the new agency's auspices. Although a launch-vehicle malfunction prevented it from reaching its intended lunar orbit, Pioneer 1 traveled approximately 70,000 miles from Earth and returned useful scientific measurements. The pace accelerated rapidly. Within less than three years, Alan Shepard became the first American in space. In 1962, John Glenn became the first American to orbit Earth. Gemini followed, developing rendezvous, docking, spacewalking, and long-duration flight techniques. Then came Apollo. On July 20, 1969—less than eleven years after NASA opened its doors—Neil Armstrong and Buzz Aldrin landed on the Moon. NASA's work would eventually extend much farther: robotic spacecraft to every planet of the solar system, astronomical observatories above Earth's atmosphere, reusable Space Shuttles, Mars rovers, international space stations, planetary-defense experiments, and telescopes capable of examining galaxies whose light began its journey billions of years ago. Yet NASA's mandate was never limited to space. The word Aeronautics came first in its name for a reason. The agency continued the NACA tradition of research into aircraft, propulsion, aerodynamics, materials, flight safety, and eventually supersonic, hypersonic, electric, and increasingly efficient aviation. The organization that opened its doors on October 1, 1958, therefore joined two frontiers: flight within Earth's atmosphere and flight beyond it.

Why It Matters: NASA's opening created a permanent civilian institution for American aeronautical research and space exploration. Built upon more than four decades of NACA expertise, the agency became one of the principal organizations through which humanity explored the Moon, planets, Sun, Earth, and universe. October 1 marks not the passage of the law that created NASA, but the day the agency itself began its work.

 

Also on This Day

1990 — The First Hubble Science Paper Is Submitted

Time not applicable

On October 1, 1990, astronomer Tod Lauer of the National Optical Astronomy Observatory submitted the first scientific paper based upon observations made by the newly launched Hubble Space Telescope. The paper concerned the core of the galaxy NGC 7457 and observations made with Hubble's Planetary Camera. The milestone came during a difficult period for Hubble. The telescope had been launched aboard Space Shuttle Discovery on April 24, 1990, amid enormous expectations. An observatory above Earth's atmosphere could avoid the blurring effects produced as starlight passed through turbulent air. Astronomers anticipated exceptionally sharp images and observations at wavelengths difficult or impossible to study from the ground. Then scientists discovered that Hubble's 2.4-meter primary mirror had been manufactured to the wrong shape. The error was extraordinarily small in ordinary terms—roughly one-fiftieth the thickness of a human hair at the mirror's edge—but enormous for a precision astronomical instrument. Hubble suffered from spherical aberration. Its images were not as sharp as intended. The problem became one of NASA's most publicized technical embarrassments. But Hubble was not useless. Astronomers learned how to characterize the optical error, and several instruments could still perform valuable observations. Image-processing techniques also recovered substantial scientific information. The October 1 paper demonstrated an important point: the flawed telescope could still do science. The paper examined the central region of NGC 7457, a lenticular galaxy tens of millions of light-years away, as astronomers investigated the structure of its nucleus and the possibility of a massive compact object there. Hubble's story would change dramatically three years later. In December 1993, astronauts aboard Space Shuttle Endeavour conducted the first Hubble servicing mission. They installed corrective optics and a new camera designed to compensate for the primary mirror's error. The results were spectacular. Hubble became one of the most scientifically productive astronomical instruments ever constructed. But its scientific career had already begun before the repair. Why It Matters: Submission of Hubble's first scientific paper showed that even the telescope's serious optical flaw could not prevent useful astronomy. The milestone also began a scientific literature that would eventually encompass discoveries involving planets, stars, galaxies, black holes, the expansion of the universe, and some of the most distant objects ever observed.

2005 — Soyuz TMA-7 Launches Expedition 12 and Gregory Olsen

03:54:53 UTC

On October 1, 2005, a Soyuz-FG rocket lifted off from the Baikonur Cosmodrome carrying Soyuz TMA-7 toward the International Space Station. Aboard were Russian cosmonaut Valery Tokarev, NASA astronaut William McArthur, and American scientist and entrepreneur Gregory Olsen. Tokarev and McArthur were beginning a long-duration stay as the principal crew of Expedition 12. Olsen was making a very different kind of journey. He became the third privately funded spaceflight participant to travel to the International Space Station, following Dennis Tito in 2001 and Mark Shuttleworth in 2002. NASA's history identifies Olsen as the third such participant. Olsen was not simply a wealthy passenger with an interest in space. He held advanced scientific degrees and had founded companies specializing in infrared and optical technologies. During his time aboard the station, he conducted experiments for the European Space Agency, participated in educational communications with students, and photographed Earth. Soyuz TMA-7 docked with the International Space Station on October 3. McArthur and Tokarev remained in orbit for approximately six months. Olsen stayed aboard the station for about eight days before returning to Earth with the departing Expedition 11 crew aboard Soyuz TMA-6. His flight belonged to a small but historically significant development. For most of the Space Age, people traveled into orbit almost exclusively as representatives of governments. Privately funded participants suggested that another category was possible. The numbers remained tiny, the costs enormous, and access extremely limited. But the idea that a private citizen could purchase transportation to orbit foreshadowed a much larger commercial human-spaceflight industry that would begin developing during the following decades.

Why It Matters: Soyuz TMA-7 continued the permanent international occupation of the ISS while Gregory Olsen's flight represented the gradual emergence of privately funded human spaceflight. The mission illustrates how an orbital station built by governments also became an early destination for people traveling under commercial arrangements.

 

The Bigger Picture

October begins with an institution. That may seem less dramatic than a rocket launch, planetary discovery, or Moon landing. Yet institutions are part of how exploration becomes possible. NASA did not invent American aeronautics on October 1, 1958. It inherited decades of expertise from NACA. It did not invent rocketry. It did not create astronomy. And it did not begin the Space Age—the Soviet Union had done that with Sputnik almost exactly one year earlier. What NASA provided was a durable organizational framework within which thousands of scientists, engineers, technicians, astronauts, mathematicians, physicians, administrators, universities, contractors, and international partners could pursue increasingly ambitious goals. The other events of October 1 illustrate how that framework evolved. In 1990, the newly launched Hubble Space Telescope was already beginning to produce scientific research despite a serious flaw. Hubble would eventually demonstrate another important characteristic of large scientific institutions: the ability to recognize a mistake, devise a solution, and recover. And Soyuz TMA-7 shows a world that had changed enormously since 1958. An American astronaut and Russian cosmonaut launched together toward an international laboratory permanently occupied by people from nations that had once competed bitterly for dominance in space. Beside them sat a privately funded participant. The progression is striking: create a national civilian space agency → build observatories beyond the atmosphere → construct an international laboratory in orbit → begin opening that environment to people traveling through commercial arrangements.

There is another reason October 1 deserves special attention. NASA was created in the geopolitical pressure of the Cold War, but the National Aeronautics and Space Act gave the new agency a broader purpose. It called for the expansion of human knowledge, preservation of the United States' role in aeronautical and space science and technology, cooperation with other nations, and the peaceful application of space activities. The history that followed did not always unfold neatly according to those aspirations. But on October 1, 1958, something enduring began. A few thousand people arrived at work under a new name. Within eleven years, members of their organization would help place human footprints on the Moon.

At a Glance

1958 — Time not applicable — NASA officially begins operations, absorbing the National Advisory Committee for Aeronautics as the core of the new American civilian space agency.

1990 — Time not applicable — Tod Lauer submits the first scientific paper based on Hubble Space Telescope observations, examining the nucleus of galaxy NGC 7457.

2005 — 03:54:53 UTC — Soyuz TMA-7 launches Valery Tokarev, William McArthur, and Gregory Olsen toward the International Space Station; Olsen becomes the third privately funded spaceflight participant to visit the station.