Happy 36th, Face on Mars!

Above is a composite of two images taken of the Cydonia region of Mars. The first image (left) was taken July 25, 1976 by NASA's Viking 1 Orbiter (image F035A72). The image includes the feature which came to be known as "the Face on Mars." Image Credit: NASA/JPL-Caltech. The second image (right) was taken April 8, 2001 by Mars Global Surveyor and is a high-resolution view of the same feature (image PIA03225). Image Credit: NASA/JP/Malin Space Science Systems

July 25th marks the 36th anniversary (July 25, 1976) of the first imaging of the Cydonia mesa of Mars (40.75° north latitude and 9.46° west longitude). The image (F035A72) was taken by the recently-arrived Viking 1 Orbiter and included several interesting features. One of these, roughly 2 km (1.2 miles) in length, came to be known as "the Face on Mars."

When the image was acquired (F035A72), Viking chief scientist Gerry Soffen dismissed the "face" in the image as a "trick of light and shadow." However, a second image, F070A13, also showed the "Face," and was acquired 35 Viking orbits later at a different sun-angle from the F035A72 image. This latter discovery was made independently by Vincent DiPietro and Gregory Molenaar, two computer engineers at NASA's Goddard Space Flight Center. DiPietro and Molenaar discovered the two misfiled images while searching through NASA archives.

The Face on Mars became one of the most striking and remarkable images taken during the Viking missions. Resembling a human face, the image caused many to hypothesize that the feature was the work of an extraterrestrial civilization.

More than 20 years after the Viking 1 images were taken, a succession of spacecraft visited Mars and collected new data from the Cydonia region. These spacecraft include NASA's Mars Global Surveyor (1997–2006) and Mars Reconnaissance Orbiter (2006-), and the European Space Agency's Mars Express probe (2003-). In contrast to the relatively low resolution of the Viking images of Cydonia, these new platforms had much improved resolution. After analysis of the higher resolution data, NASA stated that the feature was revealed to be a natural looking Martian hill whose illusory face-like appearance depended on the viewing angle and angle of illumination.

Similar optical illusions can be found in the geology of Earth. Examples of such optical illusions include the Old Man of the Mountain, the Pedra da Gávea, the Old Man of Hoy and the Badlands Guardian.

To learn more about NASA's ongoing Mars Exploration Program, visit mars.jpl.nasa.gov .

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NuSTAR: Supernova Remnants Primer

The above image shows Supernova 1987A, which exploded in February 1987. The image was taken February 1994 using the Wide Field Planetary Camera 2 aboard the Hubble Space Telescope. Image Credit: Dr. Christopher Burrows, ESA/STScI and NASA

We now continue our review of NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) mission, which launched June 13th. One of the objectives of the mission is to map historic supernova remnants. But just what are these?...

Supernova Remnants Primer

A supernova remnant (SNR) is the structure that results from the explosion of a star in a supernova. The supernova remnant is bounded by an expanding shock wave, and consists of ejected material expanding from the explosion, and the interstellar material it sweeps up and shocks along the way.

The word nova is Latin for "new," and supernovae (the plural of supernova) were so named because the objects appeared to be new stars in the heavens. Of course, the name is actually a bit ironic, since supernovae are actually stars at the end of their lifecycle, stars that are going out with a bang, so to speak.

A supernova (SNe) is the instantaneous release of ~10^51 ergs (10^31 Megatons) of energy, the result of either the catastrophic collapse of a massive star or runaway nuclear burning on the surface of a white dwarf. Although only a small fraction of the energy is released in the form of visible light, this is enough to make it appear as if a new star has appeared in the sky. The effects of the SNe are profound and far-reaching, and it is possible to see the remains of SNe that occurred many hundreds of years ago.

Classification of Supernovae (SNe)

The classification of SNe is an observational one. SNe are broken down into two groups based on the presence or absence of Hydrogen Balmer lines in their spectra at maximum brightness. Those without Balmer lines are classified as Type I SNe and those with Balmer lines are classified as Type II. Supernovae of Type I are further divided into Type Ia, Ib and Ic. Although the classification is a purely observational one, there are underlying similarities between the progenitor stars (Type Ia are understood to be low mass while Type Ib, Ic and II are high mass) that are responsible for the observed classes of SNe. 

The Life and Death of a Star

A star is engaged in a continual struggle against collapse due to the gravitational force of its own mass. In the early stages of its life (the main sequence stage), a star resists gravity with thermal pressure, as the fusion of elements in its core releases energy which heats up the star's gas. The hot gas expands, exerting an outward pressure that balances the inward force of gravity. How this battle of gravity vs. outward pressure eventually concludes depends upon the initial mass of the star. 

Massive Star 

At some point in a massive star's life, the center of the star has been converted to iron and nuclear fusion in the core is no longer an exothermal process. Nuclear fusion ceases and, without this source of thermal pressure, gravity, exerting its inexorable pull on the star, seems to be winning the battle. The star continues its collapse. Then a strange reaction takes place during which electrons and protons are pushed so close together that they merge to become neutrons, releasing energy in the form of neutrinos. There is no available space between the neutrons: they are supported by neutron degenerate pressure. This halts the gravitational collapse and the outer, more tenuous stellar material 'bounces' upon hitting the degenerate core, much like a wave hitting a sea wall bounces back on itself. The conversion of the central core to neutrons releases 10^51 ergs of neutron binding potential energy, and after the bounce, the outer layers of the star are violently ejected into the ISM.

If the star starts with between 5 and 12 times the mass of our sun, the neutron degeneracy pressure in the core is thought to be able to withstand the gravitational pressure of the star remaining after the supernova explosion. In this case, a neutron star is left in the center of the SNR. If the neutron star is rotating, it may become a pulsar, emitting radiation in a beam which sweeps the earth as the pulsar rotates. If the star is massive enough, even neutron degenerate pressure will not be able to hold up against gravitational collapse, and the remains continue to be squeezed inward by gravity, forming a singularity, or black hole.

Low Mass Stars 

In the usual scheme of things, we expect low mass stars to settle down, slowly fizzle out and become white dwarfs. Their masses are too low to bring about the collapse to a neutron star and the resulting spectacle of a supernova explosion. They resist gravity's pull with electron degenerate pressure, where the electrons are squeezed until there is no more space between them. The gravitational pressure of the star is not enough to cause the conversion to neutrons and the star has reached a stable equilibrium. However, if the white dwarf is in a binary system with a red giant, it is possible for the dwarf to accrete matter from its companion. If enough matter falls on it that it exceeds the Chandresekar limit for white dwarfs, the star is no longer stable, gravity will overcome the resistance of electron degeneracy pressure and the star will collapse. The collapse raises the temperature until carbon and oxygen in the core start to fuse, igniting a deflagration wave of runaway nuclear burning which propagates through the core in seconds. The nuclear fusion reactions create about a solar mass of radioactive 56Ni. The energy released is on the order of 10^52 ergs, and the white dwarf is completely disrupted in the process. The star can outshine entire galaxies while the nuclear fusion proceeds. This is believed to be the mechanism for Type Ia SNe. 

What is a Supernova Remnant (SNR)?

Most (99%) of the energy of a SNe is released in the form of energetic neutrinos; the remaining energy is converted into kinetic energy, accelerating the stellar material to speeds greater than the speed of sound and causing a shock wave to move outwards from the central star. The high velocity stellar material plows outwards into the ISM, compressing and heating ambient gas and sweeping it up much as a snow plow compacts and sweeps up snow. The ISM becomes enriched with the stellar material blown off in the explosion. The expanding material, and any additional material the blast collects as it travels through the interstellar medium, forms a supernova remnant (SNR).

Although in a simple model of SNRs the explosion energy is deposited evenly in all directions and the ambient material is swept up in a uniform, spherical shell, in reality, remnants are much more complicated. Small differences in the initial conditions of the progenitors, including previous mass ejections, can have important effects on ejecta propagation. External conditions, such as density enhancements, in the ISM in which the SN explodes can shape and mold the morphology of the remnant. And Rayleigh-Taylor instabilities can cause the surface of the forward shock to become rippled, mixing the ambient and stellar gases. It is not surprising that there are various types of SNR: simple  Shell type remnants  with nothing in their centers,  Crab-like remnants  or  plerions  with  pulsars  in their centers and  Composite remnants , a combination of the first two. 

How does the SNR Evolve?

As the ejecta expand out from the star, it passes through the surrounding interstellar medium, heating it from 10^7 to 10^8 K, sufficient to separate electrons from their atoms and to generate thermal X-rays. The interstellar material is accelerated by the shock wave and will be propelled away from the supernova site at somewhat less than the shock wave's initial velocity. This makes for a thin expanding shell around the supernova site encasing a relatively low density interior.

While the material swept up by the shock is much less than the mass of the stellar ejecta, the expansion of the stellar ejecta proceeds at essentially a constant velocity equal to the initial shock wave speed, typically of the order of 10,000 km/s. This is known as the "free expansion" phase and may last for approximately 200 years, at which point the shock wave has swept up as much interstellar material as the initial stellar ejecta. The supernova remnant at this time will be about 10 light years in radius. Although the remnant is radiating thermal X-ray and synchrotron radiation across a broad range of the electromagnetic spectrum (from radio to X-rays), the initial energy of the shock wave will have diminished very little. Line emission from the radioactive isotopes generated in the supernovae contribute significantly to the total apparent brightness of the remnant in the early years, but do not significantly effect the shock wave.

As the remnant sweeps up ambient mass equal to the mass of the stellar ejecta, the wave will begin to slow and the remnant enters a phase known as adiabatic expansion, or the Sedov-Taylor or blast wave phase. The internal energy of the shock continues to be very large compared to radiation losses from thermal and synchrotron radiation, so the total energy remains nearly constant. The rate of expansion is determined solely the initial energy of the shock wave and the density of the interstellar medium.

As the shock wave cools, it will become more efficient at radiating energy. Once the temperature drops below 20000 K or so, some electrons will be able to recombine with carbon and oxygen ions, enabling ultraviolet line emission which is a much more efficient radiation mechanism than the thermal X-rays and synchrotron radiation. Hence this new phase is known as the radiative phase during which X-ray radiation becomes much less apparent and the remnant cools and disperses into the surrounding medium over the course of the next 10,000 years.

Supernova remnants are extremely important for our understanding of our Galaxy. They are the source of much of the energy that heats up the interstellar medium. They are believed to be responsible for the acceleration of galactic cosmic rays. Heavy elements (up to iron) created by fusion in the stellar core are dumped into the galaxy by the mixing of the ejecta and ISM material in the remnant. Enriched, heated gas from SNR material is reprocessed to form new stars. Elements heavier than iron are created in the powerful blast of a SN explosion and are then dredged up by the shock wave and mixed into the ISM. Most of the elements (except for Hydrogen) in your body, for example, are stellar material that has been redistributed in a SNR. Understanding how SNR evolve can thus help us to understand many important phenomena. 

How Does X-ray Astronomy Fit in?

There are several mechanisms by which SNR generate X-rays. The ejecta, heated and compressed by the powerful forward shock, generates thermal and line emission in the X-ray region of the spectrum. Electrons, accelerated by the SNR shock to relativistic speeds emit synchrotron radiation when they change direction in the presence of a magnetic field. And a neutron star formed in a Type II SNe may also be a significant source of X-rays.

The X-rays emitted by SNR give us many clues that help us understand SNR, their progenitor stars, and their interaction with the ISM. We usually know little about the progenitor star, however, X-ray spectra of the shock heated ejecta in the remnant offer direct information about the composition of the progenitor star. X-ray spectra can also give information on the composition of the ISM into which the remnant is expanding, if and to what extent the elemental layers of the progenitor star are mixed with the gas of the ISM. By studying the X-ray morphologies of SNR, we can learn about how thermal conduction acts in SNR and in the ISM. Looking for X-ray synchrotron radiation is a way of getting direct evidence for cosmic ray acceleration in SNR shocks.

The hot material, the radioactive isotopes, free electrons moving in the strong magnetic field of the neutron star... all of these processes produce X-rays and gamma rays which reveal the nature of the SNR.

And now, the mission particulars...

NuSTAR is a Small Explorer mission led by the California Institute of Technology in Pasadena and managed by NASA's Jet Propulsion Laboratory, also in Pasadena, for NASA's Science Mission Directorate in Washington. The spacecraft was built by Orbital Sciences Corporation, Dulles, Virginia. Its instrument was built by a consortium including Caltech; JPL; the University of California, Berkeley (UC Berkley); Columbia University, New York; NASA's Goddard Space Flight Center, Greenbelt, Maryland; the Danish Technical University in Denmark; Lawrence Livermore National Laboratory, Livermore, California; and ATK Aerospace Systems, Goleta, California. NuSTAR will be operated by UC Berkeley, with the Italian Space Agency providing its equatorial ground station located at Malindi, Kenya. The mission's outreach program is based at Sonoma State University, Rohnert Park, California. NASA's Explorer Program is managed by Goddard. JPL is managed by Caltech for NASA. For more information on the NuSTAR mission, visit www.nasa.gov/nustar and http://www.nustar.caltech.edu/ .

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"Pioneer Anomaly" Explained

The above image is an artist's concept of NASA's Pioneer 10 spacecraft passing the planet Jupiter. Image Credit: NASA


Researchers think they finally have an explanation for the unexpected slowing of NASA's Pioneer 10 and 11 spacecraft — the so-called "Pioneer Anomaly." According to a recent paper, it seems the slowing is due to the slight, but detectable effect of heat pushing back on the spacecraft. The heat emanates from electrical current flowing through instruments and the thermoelectric power supply.  The results were published on June 12th in the online journal Physical Review Letters (prl.aps.org). The paper's lead author is  Slava Turyshev of NASA's Jet Propulsion Laboratory (JPL), Pasadena, California.


Launched in 1972 and 1973 respectively, Pioneer 10 and 11 are on an outward trajectory from our sun. In the early 1980s, navigators saw a deceleration on the two spacecraft, in the direction back toward the sun, as the spacecraft were approaching Saturn. They dismissed it as the effect of dribbles of leftover propellant still in the fuel lines after controllers had cut off the propellant. But by 1998, as the spacecraft kept traveling on their journey and were over 8 billion miles (13 billion kilometers) away from the sun, a group of scientists led by John Anderson of JPL realized there was an actual deceleration of about 300 inches per day squared (0.9 nanometers per second squared). They raised the possibility that this could be some new type of physics that contradicted Einstein's general theory of relativity.


In 2004, Turyshev decided to start gathering records stored all over the country and analyze the data to see if he could definitively figure out the source of the deceleration.  In part, he and colleagues were contemplating a deep space physics mission to investigate the anomaly, and he wanted to be sure there was one before asking NASA for a spacecraft.


He and colleagues went searching for Doppler data, the pattern of data communicated back to Earth from the spacecraft, and telemetry data, the housekeeping data sent back from the spacecraft. At the time these two Pioneers were launched, data were still being stored on punch cards. But Turyshev and colleagues were able to copy digitized files from the computer of JPL navigators who have helped steer the Pioneer spacecraft since the 1970s. They also found over a dozen of boxes of magnetic tapes stored under a staircase at JPL and received files from the National Space Science Data Center at NASA  Goddard Space Flight Center, Greenbelt, Maryland, and worked with NASA Ames Research  Center, Moffett Field, California, to save some of their boxes of magnetic optical tapes. He collected more than 43 gigabytes of data, which may not seem like a lot now, but is quite a lot of data for the 1970s. He also managed to save a vintage tape machine that was about to be discarded, so he could play the magnetic tapes.


The effort was a labor of love for Turyshev and others. The Planetary Society sent out appeals to its members to help fund the data recovery effort. NASA later also provided funding. In the process, a programmer in Canada, Viktor Toth, heard about the effort and contacted Turyshev. He helped Turyshev create a program that could read the telemetry tapes and clean up the old data.


They saw that what was happening to Pioneer wasn't happening to other spacecraft, mostly because of the way the spacecraft were built.  For example, the Voyager spacecraft are less sensitive to the effect seen on Pioneer, because its thrusters align it along three axes, whereas the Pioneer spacecraft rely on spinning to stay stable.


With all the data newly available, Turyshev and colleagues were able to calculate the heat put out by the electrical subsystems and the decay of plutonium in the Pioneer power sources, which matched the anomalous acceleration seen on both Pioneers.

And now, the mission particulars...

Pioneer 10 and 11 were managed by NASA Ames Research Center, Moffett Field, Calif. Pioneer 10's last signal was received on Earth in January 2003. Pioneer 11's last signal was received in November 1995. JPL is a division of the California Institute of Technology in Pasadena. To learn more about all of the Pioneer missions, visit www.nasa.gov/mission_pages/pioneer .


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Odyssey Prepping for Curiosity

The above image is a composite of two artist's conceptions. The left is Mars Odyssey in orbit of Mars. The right is the Mars Science Laboratory / Curiosity spacecraft during entry and landing. Image Credit: NASA/JPL-Caltech

Amid a corporate sigh of relief, NASA's Mars Odyssey spacecraft has successfully adjusted its orbital location to be in a better position to provide prompt confirmation of the August landing of the Curiosity rover.


NASA's Mars Science Laboratory spacecraft, carrying Curiosity, can send limited information directly to Earth as it enters Mars' atmosphere. Before the landing, Earth will set below the Martian horizon from the descending spacecraft's perspective, ending that direct route of communication. Odyssey will help to speed up the indirect communication process.


NASA planned for Odyssey to provide a near-real-time communication link with Curiosity during the landing. But Odyssey entered safe mode July 11th following a brief thruster burn to reposition the orbiter. If the safe mode had happened during the entry and landing, communication would have been affected, but not the rover's automated landing. But Odyssey needed yet another repositioning maneuver, or Odyssey would arrived over the landing area about two minutes after Curiosity landed.


So a spacecraft thruster burn on July 24th, lasting about six seconds, has nudged Odyssey about six minutes ahead in its orbit. Odyssey is now operating normally, and confirmation of Curiosity's landing is expected to reach Earth at about 10:31 PM PDT on August 5 (1:31 AM EDT / 05:31 UTC August 6), as originally planned.


NASA engineers have noted that Odyssey is the longest operating Mars spacecraft, so it was appropriate that Odyssey have a special role in supporting the newest arrival.Two other Mars orbiters, NASA's Mars Reconnaissance Orbiter (MRO) and the European Space Agency's Mars Express, also will be in position to receive radio transmissions from the Mars Science Laboratory during its descent. However, they will be recording information for later playback, not relaying it immediately, as only Odyssey can.


Odyssey arrived at Mars in 2001. Besides conducting its own scientific observations, it has served as a communication relay for NASA's Spirit and Opportunity Mars rovers and the Phoenix lander on the Martian surface. NASA plans to use Odyssey and the Mars Reconnaissance Orbiter as communication relays for Curiosity during that rover's two-year prime mission on Mars.


And now, the mission particulars...

Odyssey and the Mars Science Laboratory, with its Curiosity rover, are managed for NASA's Science Mission Directorate in Washington by the Jet Propulsion Laboratory (JPL), a division of the California Institute of Technology in Pasadena (Caltech). Curiosity was built at JPL.


Lockheed Martin Space Systems in Denver built Odyssey. JPL and Lockheed Martin collaborate on operating Odyssey.


For more about the Mars Odyssey mission, visit mars.jpl.nasa.gov/odyssey. For information about the Curiosity landing, visit www.nasa.gov/mars and mars.jpl.nasa.gov/msl.


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Radiation Storm from July 23rd Continues

The above X-ray image of the sun was taken on July 25th at 03:16 UTC (11:16 PM EDT July 24th) by the GOES-15 satellite. Image Credit: NOAA

Earth continues to experience a minor (S1) solar radiation storm that began July 23rd, when Active Region 1520 (AR 1520) produced a solar flare and an intense CME. Fortunately for Earth, AR 1520 was well beyond the sun's western limb at that point, and not in the line of sight of the CME. Even so, Earth is experiencing a portion of the solar radiation. A nasty CME indeed. Forecasters expect the storm to end in the next 24 hours.


To monitor solar flare activity minute by minute, visit the "Today's Space Weather" page of NOAA's Space Weather Prediction Center, URL: www.swpc.noaa.gov .

To learn more about the sun and to stay current on solar activity, visit the mission home pages of the Solar Dynamics Observatory (SDO), sdo.gsfc.nasa.gov and the Solar and Heliospheric Observatory (SOHO), sohowww.nascom.nasa.gov .

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Like Me! Really Like Me!

My apologies to Sally Field for twisting her quote. Or even bringing it up at all...

My purpose in this post is to let you know that I have a related page on Facebook. On this page you will find notices of blog postings as well as any other information I want to pass along to the Facebook community.

If have an account on Facebook, please CLICK HERE to stop by and "like" me. And thanks!

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Happy 20th, Geotail!

The above image is an artist's concept of the Geotail satellite. Image Credit: NASA

July 24 marks the 20th anniversary of the launch of the GEOTAIL satellite aboard a Delta II rocket (July 24, 1992). The GEOTAIL mission is a collaborative project undertaken by the Institute of Space and Astronautical Science (ISAS) and NASA.

The primary purpose of the Geotail mission is to study the structure and dynamics of the tail region of Earth's magnetosphere with a comprehensive set of scientific instruments. For this purpose, the orbit was designed to cover the magnetotail over a wide range of distances: 8 Re (radii) to 210 Re from the earth. This orbit also allows the mission team to study the boundary region of the magnetosphere as it skims the magnetopause at perigees. In the first two years the double lunar swing-by technique was used to keep apogees in the distant magnetotail. The apogee was lowered down to 50 Re in mid November 1994 and then to 30 Re in February 1995 in order to study substorm processes in the near-Earth tail region. The present orbit is 9 Re x 30 Re with inclination of -7° to the ecliptic plane.

The Geotail spacecraft was designed and built by ISAS under association with NASA. Geotail instruments study electric fields, magnetic fields, plasmas, energetic particles, and plasma waves.

As of this writing, the Geotail mission is still active. The Geotail, Wind, Polar, SOHO, and Cluster missions are all part of the International Solar-Terrestrial Physics (ISTP) project.

To learn more about GEOTAIL, visit science.nasa.gov/missions/geotail .

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Sally Kristen Ride (1951 – 2012)

The above image, taken in 1984, is of then-NASA astronaut Sally Ride. Image Credit: NASA

Sally Kristen Ride passed away July 23rd at her home in La Jolla, California, after a 17-month battle with pancreatic cancer. She was 61.

A native of Los Angeles, Ride graduated from high school there in 1968 and enrolled at Stanford University. At Stanford, she earned four degrees, including a doctorate in physics in 1978. She also was an accomplished athlete who played varsity tennis at Stanford after being nationally ranked as a youth.

Ride joined NASA as part of the 1978 astronaut class, the first to include women. She and five other women, along with 29 men, were selected out of 8,000 applicants. The class became known as the “Thirty-Five New Guys” and reported to the Johnson Space Center the next summer to begin training. Ride trained for five years before she and three of her classmates were assigned to STS-7. The six-day mission deployed two communications satellites and performed a number of science experiments.

Following that historic flight, Ride returned to space on another shuttle mission, STS-41G in 1984. The 8-day mission deployed the Earth Radiation Budget Satellite, conducted scientific observations of Earth, and demonstrated potential satellite refueling techniques. She was assigned to a third flight, but transitioned to a role on the Rogers Commission that investigated the Challenger accident after that shuttle was lost in January 1986. When the investigation was completed, she accepted a job as a special assistant to the NASA administrator for long range and strategic planning.

Ride left NASA in August 1987 to join the faculty at the University of California, San Diego, as a professor of physics and director of the University of California’s California Space Institute. In 2001, she founded her own company, Sally Ride Science, to pursue her long-time passion of motivating girls and young women to pursue careers in science, math and technology.

Ride received numerous honors and awards during the course of her career. Most notably, she was inducted into the National Women's Hall of Fame and the Astronaut Hall of Fame, and received the Jefferson Award for Public Service, the von Braun Award, the Lindbergh Eagle, and the NCAA’s Theodore Roosevelt Award.

For more information about Ride and her NASA career, visit go.nasa.gov/Ocn6h7 .

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July 23th CME...From Long-Gone AR 1520

The above image was taken July 23rd by the Solar Dynamics Observatory. The image captures the coronal mass ejection (CME) which erupted (at lower right) from Active Region 1520, beyond the sun's western limb. Image Credit NASA/SDO/AIA

On July 23rd Active Region 1520 (AR 1520) made more noise from well beyond the western limb of the sun. At 03:00 UTC (11:00 PM EDT July 22nd), the Solar and Heliospheric Observatory (SOHO) recorded the emergence of a solar flare from behind the limb. The AR 1520 issued a solar flare and coronal mass ejection (CME). The CME speed was rated at 2,930 km/s, or 6.5 million mph. CMEs which move this fast occur only once every 5 to 10 years.  And even though the eruption was at such an oblique angle relative to Earth, it resulted in a minor (S1) solar radiation storm at Earth. The GOES spacecraft began registering an increase in protons around 07:30 UTC (3:30 AM EDT). Forecasters expect the storm to stay at minor levels and slowly wane over the next 12 to 24 hours.

Forecasters were very grateful of the fact that this CME was not directed toward Earth. They also report that the CME will miss all of the inner planets.

To monitor solar flare activity minute by minute, visit the "Today's Space Weather" page of NOAA's Space Weather Prediction Center, URL: www.swpc.noaa.gov .

To learn more about the sun and to stay current on solar activity, visit the mission home pages of the Solar Dynamics Observatory (SDO), sdo.gsfc.nasa.gov and the Solar and Heliospheric Observatory (SOHO), sohowww.nascom.nasa.gov .

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NuSTAR: A Black Hole Primer

The above image is a four-frame illustration of the devouring of a star by a black hole. In frame 1 we see a sun-like star on an eccentric orbit plunging toward the supermassive black in the heart of a distant galaxy. In frame 2 we see that strong tidal forces near the black hole increasingly distort the star. If the star passes too close, it is ripped apart. In fram 3 we see that the part of the star facing the black hole streams toward it and forms an accretion disk. The remainder of the star just expands into space. In frame 4 we not that near the black hole, magnetic fields particles moving near the speed of light. Viewed head-on, the jet is a brilliant X-ray and radio source. Image Credit: NASA/Goddard Space Flight Center/Swift

We now continue our review of NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) mission, which launched June 13th. In this outing, we get an primer on black holes...

Black Hole Primer

Don't let the name fool you: a black hole is anything but empty space. Rather, it is a great amount of matter packed into a very small area - think of a star ten times more massive than the Sun squeezed into a sphere approximately the diameter of New York City. The result is a gravitational field so strong that nothing, not even light, can escape. In recent years, NASA instruments have painted a new picture of these strange objects that are, to many, the most fascinating objects in space.

Although the term was not coined until 1967 by Princeton physicist John Wheeler, the idea of an object in space so massive and dense that light could not escape it has been around for centuries. Most famously, black holes were predicted by Einstein's theory of general relativity, which showed that when a massive star dies, it leaves behind a small, dense remnant core. If the core's mass is more than about three times the mass of the Sun, the equations showed, the force of gravity overwhelms all other forces and produces a black hole.

Scientists can't directly observe black holes with telescopes that detect x-rays, light, or other forms of electromagnetic radiation. We can, however, infer the presence of black holes and study them by detecting their effect on other matter nearby. If a black hole passes through a cloud of interstellar matter, for example, it will draw matter inward in a process known as accretion. A similar process can occur if a normal star passes close to a black hole. In this case, the black hole can tear the star apart as it pulls it toward itself. As the attracted matter accelerates and heats up, it emits x-rays that radiate into space. Recent discoveries offer some tantalizing evidence that black holes have a dramatic influence on the neighborhoods around them - emitting powerful gamma ray bursts, devouring nearby stars, and spurring the growth of new stars in some areas while stalling it in others.

One Star's End is a Black Hole's Beginning

Most black holes form from the remnants of a large star that dies in a supernova explosion. (Smaller stars become dense neutron stars, which are not massive enough to trap light.) If the total mass of the star is large enough (about three times the mass of the Sun), it can be proven theoretically that no force can keep the star from collapsing under the influence of gravity. However, as the star collapses, a strange thing occurs. As the surface of the star nears an imaginary surface called the "event horizon," time on the star slows relative to the time kept by observers far away. When the surface reaches the event horizon, time stands still, and the star can collapse no more - it is a frozen collapsing object.

Even bigger black holes can result from stellar collisions. Soon after its launch in December 2004, NASA's Swift telescope observed the powerful, fleeting flashes of light known as gamma ray bursts. Chandra and NASA's Hubble Space Telescope later collected data from the event's "afterglow," and together the observations led astronomers to conclude that the powerful explosions can result when a black hole and a neutron star collide, producing another black hole.

Babies and Giants

Although the basic formation process is understood, one perennial mystery in the science of black holes is that they appear to exist on two radically different size scales. On the one end, there are the countless black holes that are the remnants of massive stars. Peppered throughout the Universe, these "stellar mass" black holes are generally 10 to 24 times as massive as the Sun. Astronomers spot them when another star draws near enough for some of the matter surrounding it to be snared by the black hole's gravity, churning out x-rays in the process. Most stellar black holes, however, lead isolated lives and are impossible to detect. Judging from the number of stars large enough to produce such black holes, however, scientists estimate that there are as many as ten million to a billion such black holes in the Milky Way alone.

On the other end of the size spectrum are the giants known as "supermassive" black holes, which are millions, if not billions, of times as massive as the Sun. Astronomers believe that supermassive black holes lie at the center of virtually all large galaxies, even our own Milky Way. Astronomers can detect them by watching for their effects on nearby stars and gas.

Historically, astronomers have long believed that no mid-sized black holes exist.  However, recent evidence evidence from Chandra, XMM-Newton and Hubble strengthens the case that mid-size black holes do exist. One possible mechanism for the formation of supermassive black holes involves a chain reaction of collisions of stars in compact star clusters that results in the buildup of extremely massive stars, which then collapse to form intermediate-mass black holes. The star clusters then sink to the center of the galaxy, where the intermediate-mass black holes merge to form a supermassive black hole.

And now, the mission particulars...

NuSTAR is a Small Explorer mission led by the California Institute of Technology in Pasadena and managed by NASA's Jet Propulsion Laboratory, also in Pasadena, for NASA's Science Mission Directorate in Washington. The spacecraft was built by Orbital Sciences Corporation, Dulles, Virginia. Its instrument was built by a consortium including Caltech; JPL; the University of California, Berkeley (UC Berkley); Columbia University, New York; NASA's Goddard Space Flight Center, Greenbelt, Maryland; the Danish Technical University in Denmark; Lawrence Livermore National Laboratory, Livermore, California; and ATK Aerospace Systems, Goleta, California. NuSTAR will be operated by UC Berkeley, with the Italian Space Agency providing its equatorial ground station located at Malindi, Kenya. The mission's outreach program is based at Sonoma State University, Rohnert Park, California. NASA's Explorer Program is managed by Goddard. JPL is managed by Caltech for NASA. For more information on the NuSTAR mission, visit www.nasa.gov/nustar and http://www.nustar.caltech.edu/ .

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Eta Corvi's Late Heavy Bombardment?

The above image is an artist's concept of a storm of comets around the star Eta Corvi. Image Credit: NASA/JPL-Caltech


NASA's Image of the Day Gallery for July 23rd features an image that was first published back on October 19, 2011. It's an artist's concept of a comet storm surrounding the star Eta Corvi. The image appeared as part of a news release associated with NASA's Spitzer Space Telescope.


Spitzer had detected signs of icy bodies raining down in the Eta Corvi system, just 59 light-years from Earth. The frozen downpour resembles what scientists think our solar system looked like several billion years ago during a period known as the "Late Heavy Bombardment."


During this epoch, comets and other frosty objects that fell inward from the outer solar system pummeled the inner planets. The barrage scarred our moon and produced large amounts of dust.


Eta Corvi is a spectral type F2 V yellow-white dwarf (main sequence) star, the sixth brightest in the constellation Corvus, the Crow. Eta Corvi is found at stellar coordinates (J2000, J2000) R.A. 12h 32m 04.2270s, Dec -16d 11m 45.627s and has an absolute magnitude of 2.99.

Spitzer's October 2011 announcement reported a band of dust around the star that strongly matched the contents of an obliterated giant comet. This dust is located close enough to the star that Earth-like worlds could exist, suggesting a collision took place between a planet and one or more comets. The Eta Corvi system is approximately one billion years old, which researchers think is about the right age for such a hailstorm.


The research findings were written-up in a paper published in the Astrophysical Journal. The lead author was Carey Lisse, senior research scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland.

Astronomers used Spitzer's infrared detectors to analyze the light coming from the dust around Eta Corvi. Certain chemical fingerprints were observed, including water ice, organics and rock, which indicate a giant comet source.


The light signature emitted by the dust around Eta Corvi also resembles the Almahata Sitta meteorite, which fell to Earth in fragments across Sudan in 2008. The similarities between the meteorite and the object obliterated in Eta Corvi imply a common birthplace in their respective solar systems.


A second, more massive ring of colder dust located at the far edge of the Eta Corvi system seems like the proper environment for a reservoir of cometary bodies. This bright ring, discovered in 2005, looms at about 150 times the distance from Eta Corvi as the Earth is from the sun. Our solar system has a similar region, known as the Kuiper Belt, where icy and rocky leftovers from planet formation linger. The new Spitzer data suggest that the Almahata Sitta meteorite may have originated in our own Kuiper Belt.


The Kuiper Belt was home to a vastly greater number of these frozen bodies, collectively dubbed Kuiper Belt objects. About 4 billion years ago, some 600 million years after our solar system formed, scientists think the Kuiper Belt was disturbed by a migration of the gas-giant planets Jupiter and Saturn. This jarring shift in the solar system's gravitational balance scattered the icy bodies in the Kuiper Belt, flinging the vast majority into interstellar space and producing cold dust in the belt. Some Kuiper Belt objects, however, were set on paths that crossed the orbits of the inner planets.


The resulting bombardment of comets lasted until 3.8 billion years ago. After comets impacted the side of the moon that faces Earth, magma seeped out of the lunar crust, eventually cooling into dark "seas," or maria. When viewed against the lighter surrounding areas of the lunar surface, those seas form the distinctive "Man in the Moon" visage. Comets also struck Earth or incinerated in the atmosphere, and are thought to have deposited water and carbon on our planet. This period of impacts might have helped life form by delivering its crucial ingredients.


And now, the mission particulars...


NASA's Jet Propulsion Laboratory (JPL), Pasadena, California, manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology (Caltech) in Pasadena. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA. To learn more about Spitzer, visit http://www.spitzer.caltech.edu/ and www.nasa.gov/spitzer .

More information about exoplanets and NASA's planet-finding program is at planetquest.jpl.nasa.gov .

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Land Your Own MSL/Curiosity!

The above image is a screenshot from the new Microsoft Xbox Mars Rover Landing Game. Image Credit: Microsoft/Smoking Gun

On August 5th, NASA's Mars Science Laboratory (MSL)/Curiosity rover will enter the Marian atmosphere and the mission team will experience the seven seconds of terror while the spacecraft performs the automated landing.

But if you are a Microsoft Xbox gamer, you don't have to wait until August 5th. Microsoft and NASA have collaborated to create the Kinect-based Mars Rover Landing game, in which you control the whole landing experience using your body and face. The game is available in the Xbox Live Marketplace and in a special destination on the Xbox Live dashboard dedicated to the Curiosity rover. The game allows players to use the Kinect motion sensor on the Xbox 360 console to land NASA's Curiosity rover on Mars.

Launched November 26, 2011, NASA's Mars Science Laboratory (MSL) / Curiosity rover is on track for landing at approximately 1:31 AM EDT, August 6 (10:31 PM PDT, August 5) to begin a two-year prime mission. Researchers plan to use Curiosity to study layers in Gale Crater's central mound, Mount Sharp. The mission will investigate whether the area has ever offered an environment favorable for microbial life.

NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for the NASA Science Mission Directorate, Washington.

More information about Curiosity is available online at www.nasa.gov/msl and mars.jpl.nasa.gov/msl .  You can follow the mission on Facebook at: www.facebook.com/marscuriosity  and on Twitter at: www.twitter.com/marscuriosity .

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July 23rd IRVE-3 Flight Goes Well!

The above images were taken during the July 23rd flight of IRVE-3. The left images are from two of the cameras aboard IRVE-3 showing the earth from the flight apogee of 285 miles. The right images, from the same two cameras, show IRVE-3 fully inflated prior to reentry. The Images were broadcast by NASA TV via Ustream Live. Image Credit: NASA

This morning, July 23rd, at approximately 7:01 AM EDT, a Black Brant XI rocket launched the third Inflatable Reentry Vehicle Experiment (IRVE-3) from NASA's Wallops Flight Facility (WFF) on Virginia's Eastern Shore. The flight reached an apogee of 285 miles and then inflated IRVE-3 prior to reentry.

The experiment splashed down about 20 minutes after launch. It was originally expected to land about 100 miles (161 kilometers) off of the coast of North Carolina, but mission engineers reported that the trajectory took IRVE-3 a little farther than expected. Even so, engineers report that the flight went very well.

The purpose of the IRVE-3 test was to show that a space capsule can use an inflatable outer shell to slow and protect itself as it enters an atmosphere at hypersonic speed during planetary entry and descent, or as it returns to Earth with cargo from the International Space Station.

How IRVE-3 Worked

IRVE-3 was a cone of uninflated high-tech rings covered by a thermal blanket of layers of heat resistant materials. About 6 minutes into the sub-orbital flight, the 680-pound inflatable aeroshell, or heat shield, and its payload separated from the launch vehicle's 22-inch-diameter nose cone about 280 miles over the Atlantic Ocean.

An inflation system then pumped nitrogen into the IRVE-3 aeroshell until it expanded to a mushroom shape almost 10 feet in diameter. Then the aeroshell plummeted at hypersonic speeds through Earth's atmosphere. Engineers in the Wallops control room watched as four onboard cameras confirmed the inflatable shield held its shape despite the force and high heat of reentry. Onboard instruments provided temperature and pressure data. Researchers will study that information to help develop future inflatable heat shield designs.

The IRVE-3 test was a follow-on to the successful IRVE-2, which showed an inflatable heat shield could survive intact after coming through Earth's atmosphere. IRVE-3 was the same size as IRVE-2, but had a heavier payload and was subjected to a much higher re-entry heat, more like what a heat shield might encounter in space.

The Inflatable Reentry Vehicle Experiment (IRVE-3) is part of the Hypersonic Inflatable Aerodynamic Decelerator (HIAD) Project within the Game Changing Development Program, part of NASA's Space Technology Program.

Further information on the mission is available at: www.nasa.gov/wallops

Further information on the IRVE-3 is available at: www.nasa.gov/hiad


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Hop the Bus for Pad 39A!

The above image is an aerial view of Launch Pad 39A (in the foreground) and 39B (in the background). Image Credit: NASA/Cory Huston

All aboard! For a limited time, NASA has opened for touring the launch pad that saw the start of the first manned moon landing mission (as Apollo 11) and the start of the last Space Shuttle flight (aboard Atlantis).


Launch Pad 39A at the Kennedy Space Center (KSC) in Florida is the latest, limited-time tour stop being offered by the NASA spaceport's visitor complex. The tours — which also include separate trips to KSC's 52-story tall Vehicle Assembly Building (VAB) and the Launch Control Center (LCC) — are now being offered as part of the center's 50th anniversary celebration.


Pad 39A was one of two launch complexes built in the 1960s to support the Saturn V launches to the moon, Saturn IB launches to the Skylab space station and space shuttle launches to deploy and service satellites and build the International Space Station.


Pad 39A's twin, Pad 39B, was stripped of its launch support towers last year to make way for possible future commercial and government launch vehicles. Pad 39A, which supported 92 launches since November 1967 — 12 Saturn V rockets and 80 shuttles — is being maintained to support NASA's Space Launch System (SLS) heavy-lift next generation booster now being developed.


The current downtime between launches has allowed the opportunity for the visitor complex to bring guests closer to the launch pad than ever before.


What You Get


In the new "KSC Up-Close: Launch Pad Tour," guests bus from the visitor complex to Pad 39A, following alongside the same river stone-lined "crawlerway" that rockets and shuttles once slowly rumbled across riding atop massive tank-like transporters. Previous bus tours drove this same path but then veered off to circle the security fence that surrounds the launch pad. The guards stationed at the pad will wave the bus forward, permitting the tour to proceed almost a quarter-mile (400 meters) within the pad's perimeter. Near the pad, visitors will be able to exit the bus for photo opportunities, including close-up views of the 350-foot high (107-meter) fixed service structure (FSS), rotating service structure (RSS), propellant and water tanks, flame trench and other aspects of the launch pad complex. The buses will then continue onward for drive-by views of Pad 39B, the Vehicle Assembly Building and the mobile launch platforms that moved between the VAB and pads. The tour culminates at the Apollo/Saturn V Center, where one of three remaining moon rockets is on display.


The launch pad tour is offered twice daily and takes about two hours to complete. The tour runs $25 USD for adults and $19 USD for children ages 3 to 11, plus tax, in addition to general admission to the KSC visitor complex. The pricing matches tickets for the earlier announced VAB and Launch Control Center tours.


The VAB tour, which provides visitors the chance to enter the voluminous buildingwhere Saturn rocket stages were stacked and shuttles were assembled for launch, currently offers guests a limited chance to view the space shuttle Atlantis parked inside one of its high bays. In November 2, Atlantis will be moved to the visitor complex for its permanent display.


For more about the Launch Pad Tour and the Kennedy Space Center Visitors Center, visit www.kennedyspacecenter.com .


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Catch the July 23th IRVE-3 Demo Flight

PLEASE IGNORE THE OLD LAUNCH DATE. The above image is an overview of the flight demonstration of the Inflatable Reentry Vehicle Experiment (IRVE-3). The launch is scheduled for July 23rd. Image Credit: NASA

NASA has scheduled the launch of an inflatable heat shield technology demonstration flight from its Wallops Flight Facility on Wallops Island, Virginia, for Monday, July 23. The launch is a reschedule of the July 21 launch attempt, which was scrubbed because of bad weather.


The Inflatable Reentry Vehicle Experiment (IRVE-3) is part of the Hypersonic Inflatable Aerodynamic Decelerator (HIAD) Project within the Game Changing Development Program, part of NASA's Space Technology Program. IRVE-3 is to be launched on a Black Brant XI sounding rocket and is projected to splashdown approximately 100 miles east of Cape Hatteras, North Carolina.


The launch window on Monday for all rockets, including several to test tracking systems and gather atmospheric data, is 5 to 8 AM EDT. The launch window for the IRVE-3 is 7 to 7:40 AM EDT.

If you are in the area, the NASA Visitor Center at Wallops will open at 4:30 AM EDT on launch day for viewing the launch. The Black Brant XI rocket will be visible to residents in the Wallops and southern Chesapeake Bay region.


Further information on the mission, including how to view the launch on the Internet and following the countdown on Twitter and Facebook, is available at: www.nasa.gov/wallops


NASA Television will air the IRVE-3 launch live and stream it on the agency's website at: www.nasa.gov/ntv


Further information on the IRVE-3 is available at: www.nasa.gov/hiad


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iTunes for the Apollo 11 43th Anniversary

The above image is a frame from the 2009 restoration of the Apollo 11 moon walk on July 20, 1969. Image Credit: NASA

A very happy 43th anniversary to NASA's Apollo 11 mission, the first to land humans on the surface of the Moon. On July 20, 1969 two astronauts — Apollo 11 Commander Neil A. Armstrong and Lunar Module pilot Edwin E. "Buzz" Aldrin Jr. — landed in Mare Tranquilitatis (the Sea of Tranquility) on the Moon in the Lunar Module (LM) while the Command and Service Module (CSM), with Command Module (CM) pilot Michael Collins in lunar orbit.

In recognition of this achievement, I direct your attention to a collection of video restorations (albeit a work in progress) from the Apollo 11 mission. In July 2009, NASA released restored video from the July 20, 1969, live television broadcast of the Apollo 11 moonwalk. The work was done by a team of Apollo-era engineers who helped produce the 1969 live broadcast of the moonwalk. They acquired the best of the broadcast-format video from a variety of sources for the restoration effort. These included a copy of a tape recorded at NASA's Sydney, Australia, video switching center, where down-linked television from Parkes and Honeysuckle Creek was received for transmission to the U.S.; original broadcast tapes from the CBS News Archive recorded via direct microwave and landline feeds from NASA's Johnson Space Center in Houston; and kinescopes found in film vaults at Johnson that had not been viewed since 1973. Please click and enjoy!

CLICK HERE to view the Quicktime-formatted video excerpts from the Apollo 11 mission.

CLICK HERE to bring up the iTunes page of Apollo 11 recordings.

CLICK HERE to visit the NASA commemorative site of images and video from the Apollo Program.

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Hi-C July 11th Corona Images are Stunning!

The above image composite shows one image (left) taken by NASA's High Resolution Coronal Imager (Hi-C) telescope and one image (right) taken by the Atmospheric Imaging Assembly (AIA) instrument aboard NASA's Solar Dynamics Observatory (SDO). Both images were taken during the time of the Hi-C sub-orbital flight on July 11th. Image Credit: NASA/SDO/Hi-C

Boy, oh boy. We have some really nice pics here...

Back on July 11th, from White Sands Missile Range in New Mexico, NASA performed a successful sub-orbital flight of the High Resolution Coronal Imager (HI-C). The solar telescope flew atop a Black Brant sounding rocket. Of the 602-second flight, actual data collection was expected to last for 381 seconds while Hi-C was above Earth's atmosphere. HI-C was billed as the highest resolution solar telescope ever to observe the solar corona. And now, we have the images to prove it.

CLICK HERE to see more images compared, including a video comparing the two sources.

Hi-C focused on a large active region on the sun (AR 1520) with some images revealing the dynamic structure of the solar atmosphere in fine detail. These images were taken in the extreme ultraviolet wavelength. This higher energy wavelength of light is optimal for viewing the hot solar corona.

The telescope acquired data at a rate of roughly one image every 5 seconds. Its resolution is approximately five times more detailed than the Atmospheric Imaging Assembly (AIA) instrument flying aboard NASA's Solar Dynamics Observatory (SDO). For comparison, AIA can see structures on the sun's surface with the clarity of approximately 675 miles and observes the sun in 10 wavelengths of light. Hi-C can resolve features down to roughly 135 miles, but observed the sun in just one wavelength of light.

The high-resolution images were made possible because of a set of innovations on Hi-C's optics array. Hi-C's mirrors are approximately 9 1/2 inches across, roughly the same size as the SDO instrument's. The telescope includes some of the finest mirrors ever made for space-based instrumentation. The increase in resolution of the images captured by Hi-C is similar to making the transition in television viewing from a cathode ray tube TV to high definition TV.

NASA's Marshall Space Flight Center is leading the international effort for Hi-C. Key partners include the University of Alabama at Huntsville, Smithsonian Astrophysical Observatory, University of Central Lancashire in Lancashire, England, and the Lebedev Physical Institute of the Russian Academy of Sciences.

To read more about HI-C, visit these URLs:

Apogee Imaging Systems, makers of the imaging system for the High Resolution Coronal Imager (HI-C), www.ccd.com/nasa_hic.html

NASA News, 10/21/2011 - "Marshall Scientist Dr. Jonathan Cirtain Receives Presidential Early Career Award." NASA Marshall Space Flight Center. www.nasa.gov/centers/marshall/news/news/releases/2011/11-125.html

NASA News, 06/21/2012 - "Hi-C to Investigate Activity in Solar Atmosphere." NASA Marshall Space Flight Center. www.nasa.gov/centers/marshall/news/news/releases/2012/12-064.html

NASA News, 07/05/2012 - "HI-C Sounding Rocket Mission Has Finest Mirrors Ever Made." Wallops Flight Facility, NASA Goddard Space Flight Center. www.nasa.gov/centers/wallops/news/HI-C.html

NASA News, 07/20/2012 - "NASA Telescope Captures Sharpest Images of Sun's Corona." NASA Headquarters. www.nasa.gov/home/hqnews/2012/jul/HQ_12-246_SOLAR_HI-C.html

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M7.7 Solar Flare and CME of July 19th

The above image was captured by NASA's Solar Dynamics Observatory (SDO) on July 19, 2012. It shows an M7.7 class solar flare. The image represents light in the 131 Angstrom wavelength. Credit: NASA/SDO

Active Region 1520 (AR 1520) has moved beyond the sun's western limb, but it continues to make itself known to Earth. On July 19th beginning at 05:13 UTC (1:13 AM EDT), AR 1520 erupted with an M7.7-class X-ray solar flare. The eruption also produced a coronal mass ejection (CME). NASA models suggest that the CME is not headed toward Earth, but could impact STEREO-A, one of the two satellites in the Solar Terrestrial Relations Observatory (STEREO) mission (stereo.gsfc.nasa.gov).

CLICK HERE to see a video captured by the Solar Dynamics Observatory (SDO), as well as other SDO images of the flare.


To monitor solar flare activity minute by minute, visit the "Today's Space Weather" page of NOAA's Space Weather Prediction Center, URL: http://www.swpc.noaa.gov/ .

To learn more about the sun and to stay current on solar activity, visit the mission home pages of the Solar Dynamics Observatory (SDO), sdo.gsfc.nasa.gov and the Solar and Heliospheric Observatory (SOHO), sohowww.nascom.nasa.gov .

To catch postings for all my blogs, subscribe on Twitter to twitter.com/RoamingAstro . Email feedback to: RoamingAstroInput@gmail.com . 

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Low Tech: Planisphere

In the above composite, the image on the left is a 16th-century astrolabe and the image on the right is a contemporary planisphere. Image Credit: Wikipedia contributor "Maksim" (astrolabe); Wikipedia contributor "Wammes Waggel" (planisphere).

Before smartphone apps, before the Internet, even before personal computers, amateur astronomers who were on a budget could still obtain, at little or no cost, the tools they needed to pursue their hobby. The trade-off was that they had to make the tools themselves. Here is one such nifty tool. It's called a planisphere.

A planisphere, or star wheel, is one of the most useful amateur astronomer tools. A planisphere can help you learn how to recognize stars and constellations. A predecessor to the planisphere is the astrolabe, an instrument invented in ancient Greece around 150 BC, and some say invented by the Greek astronomer, geographer, and mathematician Hipparchus.

A planisphere is very easy to learn and use. As long as you can spin the wheel to the correct local time (this does require knowing what time it is), you have at your finger tips a star chart of the nighttime sky over your head. And to take this low-tech theme one step further, why buy when you can make? And even make for free?

Of course, I understand there are still those who object. You are saying, "Why make your own planisphere? Well, for one reason, customization. Being able to make custom planispheres may help you easily focus on your astronomical subject of study. And choosing your own colors can optimize visibility, change lines, borders or even constellation art. Another reason to make your own is the self confidence you will feel when you construct something that everyone else has said you must buy before you can have. Finally, it can give you a great sense of nostalgia to remember, and to show others, what it was like before there were star chart apps...

There are several places online that provide, for free, all you need to download and create your own planisphere in no time. Here are just a few:

Make a Star Wheel! Sky and Telescope.

Planisphere. National Research Council, Canada.

Create Your Own Planisphere with Uncle Al's Sky Wheels. Ventura County Astronomical Society.

Star Wheel. Astronomy in your hands.

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Thank You, GOES!

The above image was taken October 25, 1975 from 22,000 miles above Earth by the first Geostationary Operational Environmental Satellite (GOES) of the Geostationary Satellite system. Image Credit: NOAA

We hear a lot about the GOES satellites and we get a lot of good information from them. But what exactly are they and is their full purpose? I thought we'd take a few minutes to find out, and to appreciate all that they do...

GOES is an abbreviation for Geostationary Operational Environmental Satellite, those satellites actively participating in the Geostationary Satellite system. The system is operated by the United States National Environmental Satellite, Data, and Information Service (NESDIS). The system supports weather forecasting, severe storm tracking, and meteorology research. Spacecraft and ground-based elements of the system work together to provide a continuous stream of environmental data. The National Weather Service (NWS) uses the GOES system for its United States weather monitoring and forecasting operations, and scientific researchers use the data to better understand land, atmosphere, ocean, and climate interactions.

The GOES system uses geosynchronous satellites, which have been a basic element of U.S. weather monitoring and forecasting since the launch in 1974 of the first Synchronous Meteorological Satellite, SMS-1.

There are normally three active GOES satellites at any given time. When in service, their operational designations are GOES-East (eastern North America and the Atlantic), GOES-West (western North America and the Pacific), and GOES-South (South America). Those satellites that are replaced by a newer model but still functional, are re-purposed. For example, GOES-3 is currently used as a communications relay for the South Pole research station.

The Generations of GOES
Satellites SMS-1, SMS-2, GOES 1, GOES 2, and GOES 3 (SMS-A through SMS-C/GOES-A, GOES-B through GOES-c) were essentially identical in design. They were build on a spaceframe provided by Philco-Ford. They were spin-stabilized. they carried (1) a visible infrared spin-scan radiometer (VISSR) which provided high-quality day/night cloudcover data and made radiance temperatures of the earth/atmosphere system, (2) a meteorological data collection and transmission system which relayed processed data from central weather facilities to small APT-equipped regional stations and collected and retransmitted data from remotely located earth-based platforms, and (3) a space environmental monitor (SEM) which measured proton, electron, and solar X-ray fluxes and magnetic fields. The cylindrically shaped spacecraft measured 190.5 cm in diameter and 230 cm in length, exclusive of a magnetometer that extended an additional 83 cm beyond the cylinder shell. The primary structural members were a honeycombed equipment shelf and a thrust tube. The VISSR telescope was mounted on the equipment shelf and viewed the earth through a special aperture in the side of the spacecraft. A support structure extended radially out from the thrust tube and was affixed to the solar panels, which formed the outer walls of the spacecraft and provided the primary source of electrical power. Located in the annulus-shaped space between the thrust tube and the solar panels were station-keeping and dynamics control equipment, batteries, and most of the SEM equipment. Proper spacecraft attitude and spin rate (approximately 100 rpm) were maintained by two separate sets of jet thrusters mounted around the spacecraft equator and activated by ground command. The spacecraft used both UHF and S-band frequencies in its telemetry and command subsystem. A low-power VHF transponder provided telemetry and command during launch and then served as a backup for the primary subsystem once the spacecraft had attained synchronous orbit.

Satellites GOES 4, GOES 5, GOES 6, GOES-G, and GOES 7 (GOES-D through GOES-H) were slightly different in design, but otherwise identical to the prior satellites in instrumentation and capabilities. Though they were not the first to be designated GOES, the satellites of this design are described as the "first generation" GOES design. These were constructed by Hughes Space and Communications.


Satellites GOES 8, GOES 9, GOES 10, GOES 11, and GOES 12 (GOES-I through GOES-M) were the "second generation" design  This series is a joint effort on the part of NASA and NOAA to provide continued operational monitoring of weather systems primarily over the United States, distribute meteorological data to regional and national weather offices within the USA, contribute to the development of an environmental data collection network, contribute to the search and rescue program, improve the capability for forcasting and provide real-time warnings of solar distrubances, and to extend knowledge and understanding of atmospheric processes to improve short and long-term weather forecasts. The GOES-NEXT series, extends the capabilities of the previous GOES 1-7 spacecraft. The GOES I-M spacecraft will be placed over the equator at 135 deg West or 75 deg West. The spacecraft structure is based on the Space Transportation System (STS)-launched, three-axis stabilized Insat (geostationary satellite for India) meteorological satellite design. The design allows unobstructed views of the Earth for operational coverage by the spacecraft sensors. The spacecraft configuration is a compact box-shaped main body that carries the Earth-observing instruments, a continuous-drive solar array attached to the south panel through a yoke assembly, and a solar pointing instrument gimbal mounted on the solar panel yoke. The main body accomodates the sensors, electronics, and support subsystems. The communication antennas, except the Tracking, Telemetry, and Command (TT&C) antenna, are hard-mounted to the Earth-facing panel. The Propulsion Module consists of the fuel and oxidizer tanks for the bipropellant propulsion subsystem mounted on the central cylinder. The Attitude and Orbit Control Substem (AOCS) provides attitude control of the spacecraft. The AOCS consists of the sensors, electronics, and the actuators. The GOES power is generated from the solar array and two 12 A-hr batteries. Power is automatically regulated during solar eclipses. The Image Navigation/Registration (INR) system provides Imager and Sounder data products in real-time to users. The Communications, Command, and Data Handling subsystem is comprised of antennas, receivers, transponders, transmitters, data encoders and encryptors and multiplexers. The Tracking Telemetry and Command (TT&C) subsystem provides the necessary monitor and command link between the spacecraft and the ground stations. The GOES-NEXT instruments consist of the following: (1) Earth Imaging System, a 5-channel visible and infrared radiometer which provides Earth imagery 24 hours a day; (2) Sounding System, a 19-channel discrete-filter radiometer for obtaining atmospheric temperature and moisture soundings; (3) a Space Environment Monitor (SEM), which consists of a magnetic field sensor, a solar X-ray sensor, an energetic particle sensor (EPS), and a High Energy Proton and Alpha Detector (HEPAD); (4) a Search and Rescue subsystem (SARSAT), which receives signals from 406 MHz distress beacons and relays them to the ground; (5) a Data Collection System (DCS) for collecting and relaying real-time information from Data Collection Platforms (DCPs) such as buoys, balloons, remote weather stations, ships, and aircraft; and (6) a Weather Facsimile (WEFAX) system which relays processed weather imagary from the Wallops Island station to the user community. These satellies were constructed by Space Systems/Loral.

Satellites GOES 13, GOES 14, GOES 15, and GOES 16 (GOES-N through GOES-Q) are the "third generation" of GOES satellites, constructed by Boeing (the contract was awarded to Hughes prior to their merger with Boeing). The satellites carry an imager, sounder, the Solar X-ray Imager (SXI), the Space Environment Monitor System (SEM) and a search and rescue transponder which relays distress signals to the ground. The SEM consists of two magnetometers; an Energetic Particle Sensor (EPS) composed of a High-Energy Proton and Alpha Detector (HEPAD), a Magnetosphere Electron Detector (MAGED), an Energetic Proton Electron and Alpha Detector (EPEAD), and a Magnetosphere Proton Detector (MAGPD); Energetic X-Ray Sensor (XRS) and Extreme Ultraviolet (EUV) sensors.

The "fourth generation," also called the GOES-R series of spacecraft, is in the development phase and will be constructed by Lockheed Martin. The first GOES-R series satellite is scheduled for launch in fiscal year 2015 and is expected to remain operational through December 2027.

History and Status of SMS/GOES Satellites

SMS-1 - Launched May 17, 1974 as SMS-A. Replaced by GOES 3.

SMS-2 - Launched February 6, 1975 as SMS-B. Replaced by GOES 1.

GOES 1 - Launched October 16, 1975 as SMS-C/GOES-A. Replaced by GOES 3. It later replaced SMS-2. Deactivated March 7, 1985.

GOES 2 - Launched June 16, 1977 as GOES-B. Replaced SMS-1. Then used for communications by Peacesat. Replaced by GOES 7. Deactivated May 5, 2001.

GOES 3 - Launched June 16, 1978 as GOES-C. Replaced GOES 1, now used as a communications relay for the South Pole research station.

GOES 4 - Launched September 9, 1980 as GOES-D. Decommissioned/deactivated November 9, 1988.

GOES 5 - Launched May 22, 1981 as GOES-E. Assisted by reactivated GOES 1 and GOES 4 when its VISSR failed in 1984. Finally replaced by GOES 7. Decommissioned/deactivated July 18, 1990.

GOES 6 - Launched April 28, 1983 as GOES-F. Its VISSR failed in January 1989, leaving GOES 7 as the only operational GOES satellite until the launch of GOES 8. Decommissioned/deactivated May 19, 1992.

GOES-G, Launched May 3, 1986. Intended replacement for GOES 5, but failed to orbit. Launch vehicle exploded 71 seconds after launch.

GOES 7 - Launched April 28, 1987 as GOES-H. A ground spare, it replaced GOES 5. Filled a vital role as both GOES-East and GOES-West during the wait for GOES-I to be ready. Once GOES 8 became GOES-East, GOES 7 resumed its role as GOES-West. Currently used as a communications satellite by Peacesat.

GOES 8 - Launched April 13, 1994 as GOES-I. Served as GOES-East. Suffered a design fault. Replaced in 2003 by GOES 12. Decommissioned/deactivated May 4/5, 2004.
GOES 9 - Launched May 23, 1995 as GOES-J. Served ast GOES-West. Suffered from a design fault similar to GOES-8. In late 1988, was replaced by backup satellite GOES 10. Decommissioned/deactivated on June 15, 2007.

GOES 10 - Launched April 25, 1997 as GOES-K. Place on orbit as a spare. In late 1988, replaced GOES 9 as GOES-West. Replaced by GOES 11 and later served as a backup for GOES-South. Also served temporarily as GOES-East, filling in for defective GOES 8. Decommissioned/deactivated on December 2, 2009.

GOES 11 - Launched May 3, 2000 as GOES-L. Placed on orbit as a spare. In 2006, it replaced GOES 10 as GOES-West, one year past the end of its original design life. It was replaced by GOES 15 in December 2011. Decommissioned/deactivated December 16, 2011.

GOES 12 - Launched July 23, 2001 as GOES-M. Placed on orbit as a spare. In 2003, replaced GOES 8. Its Solar X-Ray Imager failed in April 2006. It also began having thruster problems (propellant leaks) in December 2007. GOES 10 was briefly reactivated in order to fill-in for GEOS 12. It served as GOES-East until it was replaced by GOES 13 in April 2010. Was on standby. Now serving as GOES-South.

GOES 13 - Launched May 24, 2006 as GOES-N. Placed on orbit as a spare. In December 2006 its Solar X-ray Imager was damaged while observing an intence solar flare. In December 2007, substituted for GOES 12. And since April 2010, it has served as GOES-East.

GOES 14 - Launched June 27, 2009 as GOES O. Placed on orbit as a spare.

GOES 15 - Launched March 4, 2010 as GOES P. Placed on orbit as a spare. In December 2011 it replaced GEOS 11 as GOES-West.

GOES-R - Scheduled for launch in 2015

GOES-S - scheduled for launch in 2017

To learn more about the work of the GOES satellite system, visit www.oso.noaa.gov/goes

To monitor solar flare activity minute by minute, visit the "Today's Space Weather" page of NOAA's Space Weather Prediction Center, URL: www.swpc.noaa.gov/ .

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