Satellite News

When scientists discovered two great swaths of radiation encircling Earth in the 1950s, it spawned over-the-top fears about "killer electrons" and space radiation effects on Earthlings. The fears were soon quieted: the radiation doesn't reach Earth, though it can affect satellites and humans moving through the belts. Nevertheless, many mysteries about the belts – now known as the Van Allen Radiation belts – remain to this day.

Filled with electrons and energetic charged particles, the radiation belts swell and shrink in response to incoming solar energy, but no one is quite sure how. Indeed, what appears to be the same type of incoming energy has been known to cause entirely different responses on different occasions, causing increased particles in one case and particle loss in another. Theories on just what causes the belts to swell or shrink abound, with little hard evidence to distinguish between them. One big question has simply been to determine if, when the belts shrink, particles escape up and out into interplanetary space or down toward Earth. Now, a new study using multiple spacecraft simultaneously has tracked the particles and determined the escape direction for at least one event: up.

"For a long time, it was thought particles would precipitate downward out of the belts," says Drew Turner, a scientist at the University of California, Los Angeles, and first author on a paper on these results appearing onine in Nature Physics on January 29, 2012 date. "But more recently, researchers theorized that maybe particles could sweep outward. Our results for this event are clear: we saw no increase in downward precipitation."

While it may sound like a simple detail, such knowledge is not just esoteric. Indeed, the study of particle losses in the belts has so far provided more mystery and potential theories than concrete information. But understanding the radiation belts – and how they change as particles and energy come in or go out -- is a crucial part of protecting satellites that fly through the region.

The Van Allen belts fit into a larger system that stretches from the sun to Earth. The sun sends out a constant stream of solar wind, not to mention occasional much larger bursts – such as explosions from the sun's atmosphere called coronal mass ejections (CMEs) or shock fronts caused by fast solar winds overtaking slower winds called corotating interaction regions (CIRs).

When these bursts of energy move toward Earth, they can disturb Earth's own magnetic environment, known as the magnetosphere, and create a geomagnetic storm. Sometimes these storms can cause a sudden drop in the radiation belt particles, seemingly emptying the belt in only a few hours. This "drop out" can last for days. What causes the drop out, why it lasts so long, and just how the particles even leave remain unanswered questions.

Solving such a mystery requires numerous spacecraft measuring changes at several points in space to determine whether an event in one place affects an event elsewhere. The Radiation Belt Storm Probes (RBSP), scheduled to launch in August 2012, are specifically geared for such observations, but in the meantime, a team of scientists have brought together two disparate sets of a spacecraft to get an early multipoint view of the radiation belts during an event when the belts experienced a sudden loss of particles.

"We are entering an era where multi-spacecraft are key," says Vassilis Angelopoulos, a space scientist at UCLA, and the principal investigator for THEMIS and a coauthor on the paper. "Being able to unite a fleet of available resources into one study is becoming more of a necessity to turn a corner in our understanding of Earth's environment."

 In this case, the team observed a small geomagnetic storm on January 6, 2011 using the three NASA THEMIS (Time History of Events and Macroscale Interactions during Substorms) spacecraft, two GOES (Geostationary Operational Environment Satellite), operated by the National Oceanic and Atmospheric Administration (NOAA), and six POES (Polar Operational Environmental Satellite), run jointly by NOAA, and the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT) spacecraft.

The THEMIS and GOES spacecraft orbit around Earth's equatorial region, while the POES spacecraft orbit at lower altitude near the poles and travel through the radiation belts several times per day. All are equipped to study the energetic particles in the region. The observations provided an unprecedented view of a geomagnetic storm from numerous viewpoints simultaneously – and the team found unequivocally that particles escaped the radiation belts by streaming out into space, not by raining down toward Earth.

During this storm, electrons moving near the speed of light dropped out for over six hours. In that time period POES saw no increase in electrons escaping downward from the belts. On the other hand, the spacecraft did monitor a low-density patch of the belt that first appeared at the outer edges of the belts and then moved inward. This sequence is consistent with the notion that particles were streaming outward, just as the low density region of cars leaving from the front of a traffic jam moves backward over time as more and more cars are able to move forward and escape.

"This was a very simple storm," says Turner. "It's not an extreme case, so we think it's probably pretty typical of what happens in general and ongoing results from concurrent statistical studies support this."

If, indeed, electrons usually escape the radiation belts by streaming outward, it seems likely that some kind of waves aid and abet their outward motion, enabling them to reach the outer escape boundary. Hammering out this escape mechanism will be one of the jobs for RBSP, says David Sibeck at NASA's Goddard Space Flight Center in Greenbelt, Md., who is NASA's mission scientist for RBSP and project scientist for THEMIS.

"This kind of research is a key to understanding, and eventually predicting, hazardous events in the Earth’s radiation belts," says Sibeck. "It's a great comprehensive example of what we can expect to see throughout the forthcoming RBSP mission."

A second set of six mirror assemblies will arrive at Marshall in July to begin testing, and the final set of six will arrive during the fall.

The Webb Telescope is NASA's next-generation space observatory and successor to the Hubble Space Telescope. The most powerful space telescope designed, Webb will observe the most distant objects in the universe, provide images of the very first galaxies ever formed and help identify unexplored planets around distant stars. The telescope will orbit approximately one million miles from Earth.

"The Webb telescope continues to make good technological progress," said Rick Howard, JWST Program Director in Washington. "We’re currently developing a new baseline cost and schedule to ensure the success of the program."

The telescope is a combined project of NASA, the European Space Agency and the Canadian Space Agency. Northrop Grumman is the prime contractor under NASA's Goddard Space Flight Center in Greenbelt, Md. Ball Aerospace & Technologies Corp. in Boulder, Colo., is responsible for mirror development. L-3- Tinsley Laboratories Inc. in Richmond, Calif. is responsible for mirror grinding and polishing.

The crew of STS-133 closed out space shuttle Discovery's roster of accomplishments with a virtually flawless 13-day flight to attach a new module to the International Space Station and help the residents there outfit the orbiting laboratory for continued research.

Commander Steve Lindsey, Pilot Eric Boe and Mission Specialists Alvin Drew, Michael Barratt, Nicole Stott and Steve Bowen lifted off aboard Discovery on Feb. 24, 2011, from NASA's Kennedy Space Center in Florida to begin the spacecraft's pursuit of the station.

With Lindsey at the controls, Discovery rendezvoused with the station two days later and then backed the shuttle to its berthing port. Discovery's docking completed the rare occasion of having vehicles from the United States, Russia, Europe and Japan connected to the International Space Station at the same time. Along with the shuttle and the Russian Soyuz capsules, the European Space Agency's uncrewed Automated Transferred Vehicle-2 and the Japan Aerospace Exploration Agency's H-II Transfer Vehicle, or HTV, were attached to the station.

Discovery's six astronauts joined the six residents on the station for a quick welcome before they teamed up to move an equipment platform out of the shuttle's cargo bay and onto the station's truss.

The Express Logistics Carrier had been loaded on Earth with spare parts for the station, including a radiator to cool the station's systems. The parts will not be installed until they are needed as replacements.

Barratt and Stott operated the space station's robotic arm to lift the platform out of Discovery's cargo bay. They handed it off to the shuttle's own robotic arm, worked by Boe and Drew. After the station arm was maneuvered to a new location, the shuttle arm was used to hand it back to the station arm, which maneuvered the platform to its final location on the station's backbone.

Drew and Bowen left the station's Quest airlock Feb. 28 on the first of two spacewalks planned for the mission. Working inside Discovery's cargo bay and on the station, the duo put the finishing touches on the outside of the Permanent Multipurpose Module, or PMM, so it could be installed on the station and they moved a failed pump module to a stowage platform where it will stay until it can be brought back to Earth for evaluation.

Station Commander Scott Kelly worked with Barratt to drive the station's robotic arm during the spacewalk to assist Bowen and Drew. Although a glitch in the arm's control system prompted them to move to a backup location, the spacewalk's objectives were completed.

Barratt and Stott took the controls of the station's robotic arm again the next day to attach the new module to the underside of the station, connecting it to the Earth-facing side of the Unity node. The PMM is a closet for the space station, giving the crew more room to store equipment and supplies. Technicians retrofitted the Italian-built Leonardo resupply module with meteorite shielding and other gear so it could be permanently attached to the station.

The module went into space loaded with equipment, experiments and supplies for the station, so the shuttle and station crews worked throughout the mission to unpack some of the material in the PMM as well as the supplies inside the European and Japanese cargo ships.

Bowen and Drew ventured outside the station again on the mission's seventh day in space. Bowen, riding the station's robotic arm, disconnected an experiment rack from the outside of the Columbus laboratory module and Drew removed covers from the logistics carrier Discovery brought up.

The crews of both spacecraft spent the next week working inside the space station to prepare it for continuing research operations. Outfitting work inside the PMM included removing launch supports and putting unneeded materials into the HTV, which will be jettisoned later to burn up in the atmosphere.

Discovery left the space station Monday, March 7 and its crew began prepping the shuttle for its final glide back to Earth.

The shuttle soared through mostly clear skies over Florida on Wednesday, March 9. Lindsey guided Discovery onto Kennedy's runway at 11:57 a.m. EST.

After the landing, reflection mixed with celebration after Discovery completed the last of its 39 missions into orbit. Lindsey and his crew walked beneath the shuttle with NASA officials including Administrator Charles Bolden.

"I am so glad we got to land here at Kennedy, the home of Discovery," STS-133 Commander Steve Lindsey said. "As the minutes pass, I'm actually getting sadder and sadder about this being the last flight and I know all the folks involved with the shuttle program feel the same way."

NASA will preview the final space shuttle missions during media events on Wednesday, March 23, and Thursday, March 24, at the agency's Johnson Space Center in Houston.

On March 23, reporters are invited to a media availability with three of the four STS-135 crew members who will fly aboard Atlantis on the final shuttle flight in June. STS-135 Commander Chris Ferguson, Pilot Doug Hurley and Mission Specialist Sandra Magnus will demonstrate a shuttle rendezvous and docking to the International Space Station in Johnson's domed simulation facility. Reporters can film and photograph the crew, instructors and engineering support teams, as well as try the task first-hand.

On March 24, there will be a series of news briefings about shuttle Endeavour's STS-134 mission targeted to launch on April 19. NASA Television and the agency's website will broadcast the briefings live. Reporters will be able to ask questions from participating NASA locations.

8 a.m. -- Program Overview

9:30 a.m. -- STS-134 Mission Overview

11:30 a.m. -- STS-134 Spacewalk Overview

12:30 p.m. -- Alpha Magnetic Spectrometer Briefing

2 p.m. -- STS-134 Crew News Conference

The STS-134 crew will be available for interviews at Johnson by phone or in person after the briefings. To reserve an interview opportunity, reporters must contact Gayle Frere at 281-483-8645 by 5 p.m. on March 18.

To attend the STS-134 events and the STS-135 availability at Johnson, reporters must contact the Johnson newsroom at 281-483-5111 by 5 p.m. on March 14 for credentials. All required paperwork for international journalists must be submitted to the newsroom by March 14.

STS-134's 14-day mission to the International Space Station will deliver the Alpha Magnetic Spectrometer, a particle physics detector designed to operate from the station and search for various types of unusual matter. The shuttle crew also will deliver spare parts, including two S-band communications antennas, a high-pressure gas tank and additional parts for the Dextre robot. The crew also will transfer Endeavour's orbiter boom sensor system to the station truss as a permanent fixture to assist spacewalkers, if required.

STS-134 will include four spacewalks. As Endeavour undocks from the station to return to Earth, Commander Mark Kelly and Pilot Greg H. Johnson will ease the shuttle back toward the station to test new sensor technologies that could make it easier for future space vehicles to dock to the International Space Station.

Kelly and Johnson will be joined by Mission Specialists Michael Fincke, Greg Chamitoff, Andrew Feustel and European Space Agency astronaut Roberto Vittori.

The NASA Authorization Act of 2010 directs NASA to conduct the STS-135 mission, and the teams are preparing for the target launch date of June 28. More information on mission preview briefings, which are targeted for mid-June, will be forthcoming. Atlantis will carry the Raffaello multipurpose logistics module to deliver supplies, logistics and spare parts to the station. The mission also will fly a system to investigate the potential for remote-controlled robot refueling of satellites and spacecraft in orbit.

Both the Glory spacecraft and Taurus XL rocket are ready for launch tomorrow morning at 2:09:43 a.m. PST/5:09:43 a.m. EST. The weather forecast is 100 percent "go" with the possibility of some fog and a low ceiling not expected to be an issue. The call to stations for the launch team is 10:20 p.m. PST/1:20 a.m. EST.

The liftoff from Vandenberg Air Force Base in California is targeted for the middle of a 48-second launch window. Spacecraft separation will occur 13 minutes after launch. Coverage of the countdown on the Glory launch blog and on NASA TV will begin on launch day at 3:30 a.m. EST. Technical issues with ground support equipment for the Taurus XL launch vehicle led to the scrub of the first launch attempt on Feb. 23.

Data from the Glory mission will allow scientists to better understand how the sun and tiny atmospheric particles called aerosols affect Earth's climate. Both aerosols and solar energy influence the planet's energy budget -- the amount of energy entering and exiting Earth's atmosphere. An accurate measurement of these impacts is important in order to anticipate future changes to our climate and how they may affect human life.

Project management for Glory is the responsibility of NASA's Goddard Space Flight Center in Greenbelt, Md. The launch management for the mission is the responsibility of NASA's Launch Services Program at the Kennedy Space Center in Florida. Orbital Sciences Corp. of Dulles, Va., is the launch service provider to Kennedy of the four-stage Taurus XL rocket and is also builder of the Glory satellite for Goddard.