The Advanced Satellite for Cosmology and Astrophysics (ASCA), formerly Astro-D, was Japan's fourth X-ray astronomy mission. ASCA carried four X-ray telescopes and was optimized for X-ray spectroscopy. The spacecraft conducted more than 3,000 observations covering a broad range of astronomical objects. These included supernova remnants, galaxies and galaxy clusters, X-ray binary stars, active galactic nuclei, and variable stars. The satellite was successfully launched in February 1993. After suffering damage on July 14, 2000 during a geomagnetic storm, ASCA reentered the atmosphere on March 2, 2001, after more than 8 years in orbit.
The Astro-H mission, formerly known as NeXT, is Japan's sixth X-ray astronomy mission. Its scientific objectives are to trace the evolution of the largest structures in the universe; observe the behavior of material in extreme gravitational fields; determine the spin of black holes and the physical conditions within neutron stars; trace shock acceleration structures in clusters of galaxies and supernova remnants; and investigate the physics of astrophysical jets. Goddard Space Flight Center is helping to develop a high resolution Soft X-ray Spectrometer (SXS) for Astro-H. The mission is slated for launch in 2014 from Japan?s Tanegashima Space Center.
The Broad Band X-ray Telescope (BBXRT) was flown on the space shuttle Columbia (STS-35) December 2-10, 1990, as part of the ASTRO-1 payload. It was designed and built at the Laboratory for High Energy Astrophysics at NASA's Goddard Space Flight Center. BBXRT was the first focusing X-ray telescope operating over a broad energy range with a moderate energy resolution.
The Diffuse X-rays from the Local galaxy (DXL) mission is an approved sounding rocket project. Its goal is to identify and separate the X-ray emission generated by solar wind charge exchange from that of the local hot bubble to improve our understanding of both.
GEMS is a space observatory that will use a technique called X-ray polarimetry to explore distortions of space-time around spinning black holes. The paths of X-rays, and the direction in which they vibrate in space (polarization), are bent by the strong gravity near rotating black holes. GEMS therefore provides a method of determining black-hole spin independent of other techniques. GEMS will also study the structure and effects of magnetic fields around neutron stars. Launch is anticipated to occur in 2014.
The HETE-2 program is an international collaboration to study gamma-ray bursts (GRBs), which are huge releases of energy that accompany stellar explosions and mergers. HETE-2 simultaneously observes X-rays and gamma rays emitted by GRBs. This allows astronomers to precisely identify and locate GRBs. The resulting location coordinates are distributed to ground-based observers within seconds, allowing detailed observations of the initial phases of GRBs. The first HETE spacecraft was lost as a result of a launch failure in November 1996. HETE-2 was launched in October 2000 and became operational in February 2001.
The International X-ray Observatory (IXO) is a joint effort of NASA, the European Space Agency, and the Japan Aerospace Exploration Agency. It combines a large X-ray mirror with powerful new instrumentation that will explore the high-energy universe, the history and evolution of matter, how the first elements were created, and other fundamental issues. The observatory will feature a single large X-ray mirror with a 3-square-meter collecting area, providing an angular resolution of 5 arcseconds. Its suite of instruments will include multiple imaging detectors and spectrometers and a polarimeter. IXO?s launch is projected for 2021.
The Neutron star Interior Composition ExploreR (NICER) is an X-ray telescope dedicated to observe timing of neutron stars. NICER will be placed on the ISS to observe pulsars to both determine the structure of neutron stars and to demonstrate their use as deep space navigation beacons.
The NuSTAR mission will deploy the first focusing telescope for imaging the sky with high-energy X-rays. NuSTAR will undertake the first census of supermassive black holes throughout cosmic space and time, map supernova explosions, and study the most extreme active galaxies. The telescope will allow scientists to explore fundamental questions about the universe, such as what happens at the edge of a black hole, the nature of the mysterious "dark energy" pulling apart the universe, and what powered the Big Bang. The mission is slated for launch in 2012.
The Roentgen Satellite (ROSAT) is an X-ray observatory developed jointly by NASA, Germany, and the United Kingdom. The first 6 months of the mission were dedicated to an all-sky survey, using the satellite's Position Sensitive Proportional Counter detector (PSPC). The second phase was devoted to pointed observations of selected astrophysical sources. The all-sky survey was the first X-ray and extreme ultraviolet all-sky survey using an imaging telescope with an X-ray sensitivity about 1000 times better than that of a ROSAT predecessor, UHURU. In 1994, after four years of successful operation, the PSPC was shut down. The satellite was turned off in 1999.
The Rossi X-ray Timing Explorer (RXTE) satellite observed fast-moving, high-energy phenomena such as black holes, neutron stars, X-ray pulsars, and bursts of X-rays. RXTE's detectors measured changes in X-ray brightness that occur over thousandths of a second.
RXTE was developed, built, tested, and operated as an in-house project for NASA's Goddard Space Flight Center. Launched aboard a Delta rocket in 1995, the satellite originally bore the name X-Ray Timing Explorer. NASA renamed it the Bruno B. Rossi X-ray Timing Explorer in 1996. The commands to end operations were sent to RXTE in January 2012.
Suzaku, formerly Astro-E2, is Japan's fifth X-ray astronomy mission. It was developed by Japan in collaboration with NASA and MIT. The mission's objective is to observe a variety of X-ray sources at high-energy resolution and sensitivity. Suzaku is the recovery mission for ASTRO-E, which failed to achieve orbit during launch in February 2000. Suzaku launched in July 2005. Goddard Space Flight Center helped develop one of Suzaku's instruments and manages the mission's Guest Observer Program.
XACT is a new suborbital X-ray payload being developed at GSFC to test and advance Technology Readiness Levels (TRL) of several technologies that could enable future missions.
The X-ray Multi-Mirror (XMM-Newton) mission is a joint project of the European Space Agency (ESA) and NASA. XMM-Newton is designed to observe high-energy X-rays emitted by exotic astronomical objects such as pulsars, black holes, and active galaxies. The observatory collects both images and spectra. This means it can measure the energy of the X-rays emitted by an astronomical object, which allows scientists to determine many of its physical characteristics. Besides having funded elements of the XMM-Newton instrument package, NASA also provides the NASA Guest Observer Facility (GOF) for XMM Newton at Goddard Space Flight Center. ESA launched the mission in December 1999.
The X-ray Quantum Calorimeter (XQC) is a broadband, non-dispersive X-ray spectrometer built to study the soft X-ray background in the band from 0.05 to 2 keV.
XSPEC is a command-driven, interactive, X-ray spectral-fitting program. It is designed to be completely detector-independent so that it can be used for any spectrometer.
