RXTE
Full Name: Rossi X-ray Timing Explorer
Phase: Operating
Launch Date: December 30, 1995
Mission Project Home Page: http://heasarc.gsfc.nasa.gov/docs/xte/xte_1st.html
Program(s): Astrophysics Explorers, Explorers
The Rossi X-ray Timing Explorer (RXTE) is a satellite that observes the fast-moving, high-energy worlds of black holes, neutron stars, X-ray pulsars and bursts of X-rays that light up the sky and then disappear forever. For RXTE, the trick to observing these kinds of objects is all in the timing -- an ability to observe changes in X-ray brightness that occur in a mere thousandths of a second, or over several years.
How fast and how energetic are these objects? Well, some pulsars spin faster than a thousand times a second. And a neutron star produces a gravitational pull so powerful that a marshmallow striking the star's surface would hit with the force of a thousand hydrogen bombs. Astronomers study changes that happen from microseconds to months in cosmic objects to learn about how gravity works near black holes, how pulsars in binary systems are affected by mass transferring from one star to the other, and how the giant engines in distant galaxies are powered.
RXTE was launched into low-Earth orbit on December 30, 1995, and is still going strong, making unique contributions to our understanding of these extreme objects.