Gravity and Extreme Magnetism
Gravity and Extreme Magnetism SMEX (GEMS ) was planned, a space telescope NASA for the X-ray range. Because cost overruns have been expected, the construction was not approved. It should measure the polarization of X- rays from cosmic sources.
GEMS has been studied as one of six proposals for Small Explorer ( SMEX ) satellite of NASA since May 2008 and was transferred as one of two remaining projects in June 2009 in the definition phase. The start with a Pegasus rocket into a low Earth orbit should not take place before the summer of 2014. The planned mission duration would have been nine months with possibility of extension to two years. As a SMEX mission to the cost of U.S. $ 105 million ( 2008 prices, with no start-up costs ) may not exceed.
So far, polarization of cosmic X-ray radiation was measured only from one source, the Crab Nebula. With more than a hundred times improved sensitivity for polarization GEMS should reach many new sources. This inflowing matter and the curvature of spacetime near black holes should be examined. Other scientific objectives would have been the behavior of matter in extreme magnetic fields of some neutron stars and the acceleration of cosmic rays by supernova remnants.
Representation of GEMS in orbit ( with thermal shielding)
GEMS from behind ( without thermal shield )