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Mars orbiter studies possible aurorae above planet ESA NEWS RELEASE Posted: February 20, 2006 The European Space Agency's Mars Express spacecraft has seen more evidence that aurorae occur over the night side of Mars, especially over areas of the surface where variations in the magnetic properties of the crust have been detected.
Aurorae are spectacular displays often seen at the highest latitudes on Earth. On our planet, as well as on the giant planets Jupiter, Saturn, Uranus and Neptune, they occur at the foot of the planetary magnetic field lines near the poles, and are produced by charged particles - electrons, protons or ions - precipitating along these lines. "Aurorae are created when energetic charged particles collide with the upper atmosphere," says Rickard Lundin, Principal Investigator for ASPERA, from the Swedish Institute of Space Physics Physics (IRF), Kiruna, Sweden. "When they are decelerated, energy is released that causes emissions of light - aurorae. During strong aurorae the precipitating particles are accelerated and gain energy, leading to more intense light," said Lundin. The scientists have found that the energy flux of the precipitating particles is large enough that it would lead to aurorae comparable to those of weak or medium intensity at Earth. "Mars lacks a strong intrinsic magnetic or dipole field, and therefore we have not had reason to believe that aurorae occur there," said Lundin. A few years ago it was suggested that auroral phenomena could exist on Mars too. This hypothesis was reinforced by the Mars Global Surveyor discovery of crustal magnetic anomalies', most likely the remnants of an old planetary magnetic field. This discovery started speculation that auroras could also occur at Mars. In 2004, the SPICAM instrument on board Mars Express observed emissions of light during a magnetic anomalies investigation - emissions that could be due to precipitating energetic particles. The ASPERA scientists have now found that the structures of accelerated particles are indeed associated with the crustal magnetic anomalies' at Mars, but that strong acceleration mainly occurs in a region close to local midnight. The precise emissions of light that occur remain to be studied since the composition of the upper atmosphere on the night side is not well known. On the basis of atmospheric models, the scientists speculate that the classical green' emission line of oxygen might be present. "But, as we see Mars as always sunlit, the aurorae on the night side of Mars cannot be observed from Earth," added Lundin. This result appears in the 17 February issue of the journal Science. |
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Commander Steve Lindsey and his crew, the astronauts set to fly the second post-Columbia test flight, hold an informal news conference with reporters at Kennedy Space Center on Feb. 17. The crew is in Florida to examine hardware and equipment that will be carried on the STS-121 flight of shuttle Discovery.
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NASA Administrator Mike Griffin and his No. 2, Shana Dale, appear before the House Science Committee on Feb. 16 to defend President Bush's proposed 2007 budget for the space agency. Congressmen grill Griffin and Dale about the budget's plans to cut funding for some science programs.
With the four test flights complete, NASA declared the space shuttle a fully operational program. The crews were expanded, commercial payloads were welcomed aboard and the mission plans became much more hectic. This new era began with Columbia's STS-5 flight that launched the ANIK-C3 and SBS-C commercial communications satellites from the shuttle's payload bay. Commander Vance Brand, pilot Bob Overmyer and mission specialists Joe Allen and Bill Lenoir narrate highlights from their November 1982 mission in this post-flight presentation.
The developmental test flights of the space shuttle concluded with Columbia's STS-4 mission. Commander Ken Mattingly and pilot Henry Hartsfield spent a week in space examining orbiter systems and running science experiments. The 1982 flight ended on the Fourth of July with President Reagan at the landing site to witness Columbia's return and the new orbiter Challenger leaving for Kennedy Space Center. Watch this STS-4 post-flight crew presentation film.
Columbia's STS-3 mission is best remembered in the history books for its conclusion -- the first and so far only landing at the picturesque Northrup Strip at White Sands, New Mexico. In this post-flight presentation film, the crew describes the highlights of the March 1982 mission and shows some of the fun they had in orbit. The commander also tells how he accidentally "popped a wheelie" before bringing the nose gear down to the runway surface.
Seven months after the successful maiden voyage of space shuttle Columbia, astronauts Joe Engle and Richard Truly took the orbiter back into space on mission STS-2. The November 12, 1981 launch demonstrated that the space shuttle was the world's first reusable manned spacecraft. Although their mission would be cut short, Engle and Truly performed the first tests of the shuttle's Canadian-made robotic arm. The crew tells the story of the mission in this post-flight presentation.