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  NASA's Fermi Gamma-ray Space Telescope

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Author Topic:   NASA's Fermi Gamma-ray Space Telescope
Robert Pearlman
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posted 02-08-2008 10:04 AM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
NASA release
NASA Calls for Suggestions to Re-Name Future Telescope Mission

NASA announced Thursday that members of the general public from around the world will have a chance to suggest a new name for the cutting edge Gamma-ray Large Area Space Telescope, otherwise known as GLAST, observatory before it launches in mid-2008. The satellite will observe some of the most powerful forces known in the universe.

"The idea is to give people a chance to come up with a name that will fully engage the public in the GLAST mission," said Steve Ritz, the mission's project scientist at NASA's Goddard Space Flight Center, Greenbelt, Md.

The mission's scientific objectives are to:

  • Explore the most extreme environments in the universe, where nature harnesses energies far beyond anything possible on Earth
  • Search for signs of new laws of physics and what composes the mysterious dark matter
  • Explain how black holes accelerate immense jets of material to nearly light speed
  • Help crack the mysteries of the stupendously powerful explosions known as gamma-ray bursts
  • Answer long-standing questions about a broad range of phenomena, including solar flares, pulsars and the origin of cosmic rays
"We're looking for name suggestions that will capture the excitement of GLAST's mission and call attention to gamma-ray and high-energy astronomy. We are looking for something memorable to commemorate this spectacular new astronomy mission," said Alan Stern, associate administrator for Science at NASA Headquarters in Washington. "We hope someone will come up with a name that is catchy, easy to say and will help make the satellite and its mission a topic of dinner table and classroom discussion."

Suggestions for the mission's new name can be an acronym, but it is not a requirement. Any suggestions for naming the telescope after a scientist may only include names of deceased scientists whose names are not already used for other NASA missions. All suggestions will be considered. The period for accepting names closes on March 31, 2008. Participants must include a statement of 25 words or less about why their suggestion would be a strong name for the mission. Multiple suggestions are encouraged.

Anyone who drops a name into the "Name That Satellite!" suggestion box on the Web page can choose to receive a "Certificate of Participation" via return e-mail. Participants also may choose to receive the NASA press release announcing the new mission name. The announcement is expected approximately 60 days after launch of the telescope.

NASA's GLAST mission is an astrophysics and particle physics partnership, developed in collaboration with the U.S. Department of Energy, along with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden, and the U.S.

Robert Pearlman
Editor

Posts: 27328
From: Houston, TX
Registered: Nov 1999

posted 03-05-2008 08:09 AM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
NASA release
GLAST arrives in Florida to prepare for launch

NASA's Gamma-ray Large Area Space Telescope, or GLAST, arrived Tuesday at the Astrotech payload processing facility near the Kennedy Space Center to begin final preparations for launch. Liftoff of GLAST aboard a Delta II rocket is currently targeted for 11:45 a.m. EDT on May 16.

GLAST is a collaborative mission with the U.S. Department of Energy, international partners from France, Germany, Italy, Japan and Sweden, and numerous academic institutions from the U.S. and abroad. The spacecraft will explore the most extreme environments in the universe, and answer questions about supermassive black hole systems, pulsars and the origin of cosmic rays. It also will study the mystery of powerful explosions known as gamma-ray bursts.

The milestones to be accomplished over the next two months include attaching the Ku-band communications antenna and the two sets of solar arrays, a complete checkout of GLAST's scientific instruments, installing the spacecraft's battery, and loading aboard the observatory's propellant. These activities will be performed by General Dynamics, builder of the spacecraft for NASA. GLAST currently is scheduled to be transported to Pad 17-B at Cape Canaveral Air Force Station on May 1.

The rocket that will launch GLAST is a Delta II 7920-H, manufactured and prepared for launch by United Launch Alliance. It is a heavier-lift model of the standard Delta II that uses larger solid rocket boosters. The first stage is scheduled to be erected on Pad 17-B the week of March 17.

The following week, the nine strap-on solid rocket boosters will be raised and attached. The second stage, which burns hypergolic propellants, will be hoisted atop the first stage in late March. Next, the fairing that will surround the spacecraft will be hoisted into the clean room of the mobile service tower.

Engineers will perform several tests of the Delta II. In late April, the first stage will be loaded with liquid oxygen and checked for leaks. The following day, a simulated flight test will be performed, testing the vehicle's post-liftoff flight events without fuel aboard. The electrical and mechanical systems of the entire Delta II will be exercised during this test.

Once the GLAST payload is atop the launch vehicle, a final major test will be performed. The combined minus count and plus count test simulates all events as they will occur on launch day, but without propellants aboard the vehicle.

The NASA Launch Services Program at Kennedy Space Center is responsible for the countdown and launch management of the Delta II GLAST mission.

Robert Pearlman
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From: Houston, TX
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posted 05-15-2008 09:35 PM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
collectSPACE member Ben Cooper had the opportunity on Thursday to photograph GLAST as it was still being prepared for launch:

Robert Pearlman
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From: Houston, TX
Registered: Nov 1999

posted 05-23-2008 10:59 PM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
NASA release
NASA'S GLAST Space Telescope to Launch Aboard Delta II on June 3

Launch of NASA's Gamma-ray Large Area Space Telescope, or GLAST, is targeted for Tuesday, June 3, from Pad 17-B at Cape Canaveral Air Force Station, Fla. The launch window extends from 11:45 a.m. to 1:40 p.m. EDT and remains unchanged through Aug. 7. The June 3 launch date is dependent on space shuttle Discovery's May 31 liftoff, and will move if the shuttle launch is delayed.

NASA's new gamma-ray observatory will open a wide window on the universe through the study of Gamma rays, the highest-energy form of light. GLAST data will enable scientists to answer persistent questions across a broad range of topics, including supermassive black-hole systems, pulsars, the origin of cosmic rays, and searches for signals of new physics.

NASA will hold a pre-launch news conference at NASA's Kennedy Space Center news center at 1 p.m. on Sunday, June 1. The briefing will be carried live on NASA Television.

A prelaunch webcast will take place on Monday, June 2 at noon on NASA Direct, Kennedy's Internet broadcasting network. GLAST's launch director will explain how the countdown will unfold on launch day, discuss how the spacecraft and Delta II launch vehicle were prepared for liftoff, and viewers will hear GLAST's project scientist explain the mission's goals.

On Tuesday, June 3, NASA TV coverage of the launch will begin at 9:30 a.m. and conclude after spacecraft separation from the Delta II rocket, which occurs 75 minutes after launch. Coverage will be carried on the NASA TV Media Channel. The broadcast network HDNet also will carry the launch in high-definition television format from 11:30 a.m. until noon.

Robert Pearlman
Editor

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From: Houston, TX
Registered: Nov 1999

posted 06-05-2008 06:51 PM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
NASA release
NASA Targets GLAST Launch for No Earlier Than June 11

NASA has set no earlier than June 11 as the new target launch date for the Gamma-ray Large Area Space Telescope, or GLAST, from Cape Canaveral Air Force Station in Florida. The launch window extends from 11:45 a.m. to 1:40 p.m. EDT.

NASA initially had targeted June 7 for the GLAST launch aboard a Delta II rocket. Additional time was needed to replace the rocket's flight termination system battery, which indicated a problem Wednesday.

Launch commentary on NASA Television's Media Channel will begin at 9:45 a.m. EDT on June 11.

Robert Pearlman
Editor

Posts: 27328
From: Houston, TX
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posted 06-11-2008 07:51 AM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
NASA update for June 11 at 8:15 a.m. EDT
The liftoff of NASA's Gamma-Ray Large Area Space Telescope (GLAST) spacecraft remains on schedule today. The launch window opens at 11:45 a.m. and extends to 1:40 p.m. EDT.

GLAST will be launched aboard a United Launch Alliance Delta II rocket from Launch Pad 17-B at Cape Canaveral Air Force Station on the sunny east coast of central Florida.

Early this morning the mobile service tower was retracted from around the rocket to allow fueling of liquid oxygen, for the final phase of the launch countdown.

The sky is brilliant at this time with a 40 percent chance of weather concerns to hinder today's launch.

With high sensitivity GLAST is the first imaging gamma-ray observatory to survey the entire sky every day. It will give scientists a unique opportunity to learn about the ever-changing universe at extreme energies. GLAST will detect thousands of gamma-ray sources, most of which will be supermassive black holes in the cores of distant galaxies.

Robert Pearlman
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posted 06-11-2008 10:52 AM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
After a brief outage at the Antigua Island tracking station, the launch of GLAST has been reset for 12:05 p.m. EDT.

Robert Pearlman
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From: Houston, TX
Registered: Nov 1999

posted 06-11-2008 11:06 AM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
NASA's Gamma-ray Large Area Space Telescope (GLAST) was launched at 12:05 p.m. EDT from Pad 17-B at Cape Canaveral Air Force Station to search "for unseen physics in the stars of the galaxies".

NASA's GLAST Launch Successful

NASA's Gamma-ray Large Area Space Telescope, or GLAST, successfully launched aboard a Delta II rocket from Cape Canaveral Air Force Station in Florida at 12:05 p.m. EDT today.

The GLAST observatory separated from the second stage of the Delta II at 1:20 p.m. and the flight computer immediately began powering up the components necessary to control the satellite. Twelve minutes after separating from the launch vehicle, both GLAST solar arrays were deployed. The arrays immediately began producing the power necessary to maintain the satellite and instruments. The operations team continues to check out the spacecraft subsystems.

"The entire GLAST Team is elated the observatory is now on-orbit and all systems continue to operate as planned," said GLAST program manager Kevin Grady of NASA's Goddard Space Flight Center in Greenbelt, Md.

After a 75-minute flight, the GLAST spacecraft was deployed into low Earth orbit. It will begin to transmit initial instrument data after about three weeks. The telescope will explore the most extreme environments in the universe, searching for signs of new laws of physics and investigating what composes mysterious dark matter. It will seek explanations for how black holes accelerate immense jets of material to nearly light speed, and look for clues to crack the mysteries behind powerful explosions known as gamma-ray bursts.

"After a 60-day checkout and initial calibration period, we'll begin science operations," said Steve Ritz, GLAST project scientist at Goddard. "GLAST soon will be telling scientists about many new objects to study, and this information will be available on the internet for the world to see."

NASA's GLAST mission is an astrophysics and particle physics partnership, developed in collaboration with the U.S. Department of Energy, along with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden, and the U.S.

Robert Pearlman
Editor

Posts: 27328
From: Houston, TX
Registered: Nov 1999

posted 08-26-2008 03:50 PM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
NASA release
NASA Renames Observatory For Fermi, Reveals Entire Gamma-Ray Sky

NASA's newest observatory, the Gamma-Ray Large Area Space Telescope, or GLAST, has begun its mission of exploring the universe in high-energy gamma rays. The spacecraft and its revolutionary instruments passed their orbital checkout with flying colors.

NASA announced today that GLAST has been renamed the Fermi Gamma-ray Space Telescope. The new name honors Prof. Enrico Fermi (1901 - 1954), a pioneer in high-energy physics.

"Enrico Fermi was the first person to suggest how cosmic particles could be accelerated to high speeds," said Paul Hertz, chief scientist for NASA's Science Mission Directorate at NASA Headquarters in Washington. "His theory provides the foundation for understanding the new phenomena his namesake telescope will discover."

Scientists expect Fermi will discover many new pulsars in our own galaxy, reveal powerful processes near supermassive black holes at the cores of thousands of active galaxies and enable a search for signs of new physical laws.

For two months following the spacecraft's June 11 launch, scientists tested and calibrated its two instruments, the Large Area Telescope (LAT) and the GLAST Burst Monitor (GBM).

The LAT team today unveiled an all-sky image showing the glowing gas of the Milky Way, blinking pulsars, and a flaring galaxy billions of light-years away. The map combines 95 hours of the instrument's "first light" observations. A similar image, produced by NASA's now-defunct Compton Gamma-ray Observatory, took years of observations to produce.

The image shows gas and dust in the plane of the Milky Way glowing in gamma rays due to collisions with accelerated nuclei called cosmic rays. The famous Crab Nebula and Vela pulsars also shine brightly at these wavelengths. These fast-spinning neutron stars, which form when massive stars die, were originally discovered by their radio emissions. The image's third pulsar, named Geminga and located in Gemini, is not a radio source. It was discovered by an earlier gamma-ray satellite. Fermi is expected to discover many more radio-quiet pulsars, providing key information about how these exotic objects work.

A fourth bright spot in the LAT image lies some 7.1 billion light-years away, far beyond our galaxy. This is 3C 454.3 in Pegasus, a type of active galaxy called a blazar. It's now undergoing a flaring episode that makes it especially bright.

The LAT scans the entire sky every three hours when operating in survey mode, which will occupy most of the telescope's observing time during the first year of operations. These fast snapshots will let scientists monitor rapidly changing sources.

The instrument detects photons with energies ranging from 20 million electron volts to over 300 billion electron volts. The high end of this range, which corresponds to energies more than 5 million times greater than dental X-rays, is little explored.

The spacecraft's secondary instrument, the GBM, spotted 31 gamma-ray bursts in its first month of operations. These high-energy blasts occur when massive stars die or when orbiting neutron stars spiral together and merge.

The GBM is sensitive to less energetic gamma rays than the LAT. Bursts seen by both instruments will provide an unprecedented look across a broad gamma-ray spectrum, enabling scientists to peer into the processes powering these events.

NASA's Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership, developed in collaboration with the U.S. Department of Energy, along with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden and the U.S.

Robert Pearlman
Editor

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From: Houston, TX
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posted 05-01-2013 03:22 PM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
NASA release
The Day NASA's Fermi Dodged a 1.5-ton Bullet

NASA scientists don't often learn that their spacecraft is at risk of crashing into another satellite. But when Julie McEnery, the project scientist for NASA's Fermi Gamma-ray Space Telescope, checked her email on March 29, 2012, she found herself facing this precise situation.

While Fermi is in fine shape today, continuing its mission to map the highest-energy light in the universe, the story of how it sidestepped a potential disaster offers a glimpse at an underappreciated aspect of managing a space mission: orbital traffic control.

As McEnery worked through her inbox, an automatically generated report arrived from NASA's Robotic Conjunction Assessment Risk Analysis (CARA) team based at NASA's Goddard Space Flight Center in Greenbelt, Md. On scanning the document, she discovered that Fermi was just one week away from an unusually close encounter with Cosmos 1805, a defunct spy satellite dating back to the Cold War.

The two objects, speeding around Earth at thousands of miles an hour in nearly perpendicular orbits, were expected to miss each other by a mere 700 feet.

"My immediate reaction was, 'Whoa, this is different from anything we've seen before!'" McEnery recalled.

Although the forecast indicated a close call, satellite operators have learned the hard way that they can't be too careful. The uncertainties in predicting spacecraft positions a week into the future can be much larger than the distances forecast for their closest approach.

This was most dramatically demonstrated on Feb. 10, 2009, when a study revealed that Cosmos 2251, a dead Russian communications satellite, would pass about 1,900 feet from the functioning Iridium 33 communications satellite later in the day. At the predicted time of closest approach, all contact with Iridium 33 was lost. Radar revealed clouds of debris traveling along the orbits of both spacecraft, confirming the first known satellite-to-satellite collision.

That crash generated thousands of fragments large enough to be tracked and many smaller pieces that evade detection. Much of the wreckage remains a hazard to operating spacecraft because only about 20 percent of the trackable pieces have reentered the atmosphere.

With a speed relative to Fermi of 27,000 mph, a direct hit by the 3,100-pound Cosmos 1805 would release as much energy as two and a half tons of high explosives, destroying both spacecraft.

Despite the apparent crowding in Earth orbit, there's usually a vast amount of space between individual objects. Close approaches -- also known as conjunctions -- with fragments, rocket bodies and active payloads remain infrequent events. Moreover, few of the potential conjunctions identified a week into the future will actually materialize.

"It's similar to forecasting rain at a specific time and place a week in advance," said Goddard's Eric Stoneking, the attitude control lead engineer for Fermi. "As the date approaches, uncertainties in the prediction decrease and the initial picture may change dramatically."

Twice before, the Fermi team had been alerted to potential conjunctions, and on both occasions the threats evaporated. It was possible the Cosmos 1805 encounter would vanish as well, and the spacecraft's observations could continue without interruption.

But the update on Friday, March 30, indicated otherwise. The satellites would occupy the same point in space within 30 milliseconds of each other.

"It was clear we had to be ready to move Fermi out of the way, and that's when I alerted our Flight Dynamics Team that we were planning a maneuver," McEnery said.

The only way to accomplish this was by firing thrusters designed to ensure that Fermi would never pose a threat to another satellite. Intended for use at the end of Fermi's operating life, the thrusters were designed to take it out of orbit and allow it burn up in the atmosphere.

Because a failure of this system, such as a propellant leak or an explosion, could have ended Fermi's mission prematurely, the thrusters had never been tested, adding a new source of anxiety for McEnery.

"You can't help but be nervous thinking about highly flammable fluids heading down pipes they'd never flowed down before," she said. "But having done this, we now know the system works as designed, and it gives us confidence should we need to maneuver again in the future."

The Goddard CARA team determined how big a push Fermi would need to mitigate the threat. Working with the Joint Space Operations Center (JSpOC) at Vandenberg Air Force Base in California, CARA scientists also checked that the projected new orbit wouldn't put Fermi on course for a conjunction with another object. The Flight Operations Team selected possible times for the primary maneuver and, just in case, up to three additional ones.

Over the weekend, the radar and optical sensors of the U.S. Space Surveillance Network continued keeping tabs on Cosmos 1805 and every other artificial object larger than 4 inches across in Earth orbit. Of the 17,000 objects currently tracked, only about 7 percent are active satellites.

Once each day, JSpOC analyzes the updated orbits, looks for possible conjunctions a week or more into the future, and notifies the Goddard CARA team of any events involving NASA's robotic missions. Another group at NASA's Johnson Space Flight Center in Houston performs the same function for all spacecraft carrying astronauts, including the International Space Station.

By Tuesday, April 3, the threat still had not receded and all plans were in place for firing Fermi's thrusters.

Shortly after noon EDT, the spacecraft stopped scanning the sky and oriented itself along its direction of travel. It then parked its solar panels and tucked away its high-gain antenna to protect them from the thruster exhaust.

"The maneuver, which was performed by the spacecraft itself based on procedures we developed a long time ago, was very simple, just firing all thrusters for one second," Stoneking explained. "There was a lot of suspense and tension leading up to it, but once it was over, we just sighed with relief that it all went well."

By 1 p.m., Fermi was back to doing science. A few hours later, the various teams met to evaluate the results of the maneuver and determine if another would be required. When the two spacecraft reached their long-awaited conjunction the following day, they would miss by a comfortable margin of 6 miles, with no further actions needed.

"A huge weight was lifted," McEnery said. "I felt like I'd lost 20 pounds."

Last year, the Goddard CARA team participated in collision-avoidance maneuvers for seven other missions. A month before the Fermi conjunction came to light, Landsat 7 dodged pieces of Fengyun-1C, a Chinese weather satellite deliberately destroyed in 2007 as part of a military test. And in May and October, respectively, NASA's Aura and CALIPSO Earth-observing satellites took steps to avoid fragments from Cosmos 2251.

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