Alpha Magnetic Spectrometer In Limbo
Now that Atlantis has safely returned to Earth, she only has two scheduled missions left. Her last flight, STS-125, is scheduled for September 10, 2008. That will be the servicing mission for the Hubble Space Telescope. As part of the mission a docking adapter will be installed, making future servicing missions by Orion possible. Refurbishing HST was nearly cancelled, but was saved by support from both scientists and the public.
The Alpha Magnetic Spectrometer is designed to be attached to ISS. It incorporates superconducting magnets to detect cosmic rays striking Earth. It may find the signatures of antimatter in the early Universe. A Space Station is an unprecedented platform for such observations. AMS is a collaboration of 16 countries who have spent 1.5 billion US on the project. It is the most important physics experiment planned for ISS.
Though they strike Earth constantly, relatively little is known about cosmic rays. These particles reach energies far higher than any human accelerator can achieve. The highest energy cosmic rays, nicknamed "Oh My God" particles, have energies far greater than physics can explain. These particles may have originated at a time near the Big Bang. Their immense energies are one more indicator that the speed of light has slowed.
Nearly everyone has experienced the power of a thunderstorm. We are taught in school that lightning originates from static discharges within storm clouds. What triggers those discharges is unknown. The tracks of cosmic rays, striking and scattering particles in the atmosphere, are very similiar to lightning. Some researchers have suggested that cosmic rays are the cause of lightning! Since cosmic rays fall nearly steadily across Earth's surface, that is a hypothesis that needs to be tested. If cosmic rays cause lightning, that is one more example of how our lives are intimately entwined with Space.
The AMS is nearly completed and sitting in a clean room. Unfortunately, with the shuttle program scheduled to end in 2010, there is no longer a flight scheduled to take AMS into Space. Alternatives have been studied, but adapting the experiment to another spacecraft would cost hundreds of millions. Grounding the experiment would be a major disappointment for scientists and international partners. Physicists have not given up; the experiment is still scheduled to be received by NASA in 2008 and prepared for flight.
There are one, possibly two hopes left. NASA has allowed two "contingency" flights to ISS in case something goes wrong with a scheduled mission. If these flights are not used up, one of them could be used to orbit AMS. More ISS missions are a good thing, for they allow more supplies and crew changes. This may mean extending the shuttle program past 2010, but with all the delays that may happen anyway.
Adding a flight will also narrow the "gap" between shuttle retirement and the first Orion flights. If shuttle is retired in 2010 and Orion does not fly until 2013 (2014? 2016?) it will be the longest gap in US human spaceflight since 1975-81. During that period ISS would be completely dependent on Russian spacecraft. We can only hope that private spacecraft can help fill the gap.
Just as scientists and the public successfully lobbied to repair Hubble, now is the time to start lobbying for AMS. As before, NASA may examine alternatives before concluding that a shuttle mission is needed. This is a very important experiment that international partners have already paid for. Leaving AMS on the ground would remove one scientific justification for ISS. The Alpha Magnetic Spectrometer deserves to fly.