Rossi X-ray Timing Explorer


The Rossi X-ray Timing Explorer was a satellite that observed the time variation of astronomical X-ray sources, named after physicist Bruno Rossi. The RXTE had three instruments—an All Sky Monitor, the Proportional Counter Array, and the High-Energy X-ray Timing Experiment. The RXTE observed X-rays from black holes, neutron stars, X-ray pulsars and X-ray bursts. It was funded as part of the Explorer program, and is sometimes also called Explorer 69.
RXTE had a mass of 3200 kg and was launched from Cape Canaveral on 30 December 1995 on a Delta rocket. Its International Designator is .

History

Observations from the Rossi X-ray Timing Explorer have been used as evidence for the existence of the frame-dragging effect predicted by the theory of general relativity. RXTE results have, as of late 2007, been used in more than 1400 scientific papers.
In January 2006, it was announced that Rossi had been used to locate a candidate intermediate-mass black hole named M82 X-1. In February 2006, data from RXTE was used to prove that the diffuse background X-ray glow in our galaxy comes from innumerable, previously undetected white dwarfs and from other stars' coronae. In April 2008, RXTE data was used to infer the size of the smallest known black hole.
RXTE ceased science operations on 3 January 2012.
NASA scientists said that the decommissioned RXTE would re-enter the Earth's atmosphere "between 2014 and 2023". Later it became clear that the satellite would re-enter in late April or early May 2018, and the spacecraft fell out of orbit on April 30, 2018.

Instruments

All-Sky Monitor (ASM)

The ASM consisted of three wide-angle shadow cameras equipped with proportional counters with a total collecting area of 90 square cm. The instrumental properties were:
It was built by the CSR at MIT. The principal investigator was .

Proportional Counter Array (PCA)

The PCA was an array of five proportional counters with a total collecting area of 6500 square cm. The instrument was built by the EUD at GSFC. The PCA principal investigator was Dr. Jean H. Swank.
The instrumental properties were:
The HEXTE consisted of two clusters each containing four phoswich scintillation detectors. Each cluster could "rock" along mutually orthogonal directions to provide background measurements 1.5 or 3.0 degrees away from the source every 16 to 128 s. In addition, the input was sampled at 8 microseconds so as to detect time varying phenomena. Automatic gain control was provided by using a radioactive source mounted in each detector's field of view. The HEXTE's basic properties were:
The HEXTE was designed and built by the at the University of California, San Diego. The HEXTE principal investigator was .