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XTE (RXTE, Rossi, Explorer 69)


The XTE (X-Ray Timing Explorer), renamed on orbit RXTE (Rossi X-Ray Timing Explorer) mission has the primary objective to study the temporal and broad-band spectral phenomena associated with stellar and galactic systems containing compact objects in the energy range 2--200 keV and in time scales from microseconds to years.

The scientific instruments consists of two pointed instruments,

  • Proportional Counter Array (PCA) has five xenon gas proportional counter detectors (2 - 60 keV). The PCA has a large collecting area (6250 cm²).
  • High Energy X-ray Timing Experiment (HEXTE) extends the X-ray sensitivity of RXTE up to 200 keV.

and the All Sky Monitor (ASM), which scans over 70% of the sky each orbit.

  • All Sky Monitor (ASM) rotates in such a way as to scan most of the sky every 1.5 hours, at 2-10 keV. monitoring the long-term behavior of a number of the brightest X-ray sources.

All of the XTE observing time will be available to the international scientific community through a peer review of submitted proposals. XTE uses a new spacecraft design that allows flexible operations through rapid pointing, high data rates, and nearly continuous receipt of data at the Science Operations Center at Goddard Space Flight Center via a Multiple Access link to the Tracking and Data Relay Satellite System (TDRSS). XTE is highly maneuverable with a slew rate of greater than 6 degrees per minute. The PCA/HEXTE can be pointed anywhere in the sky to an accuracy of less than 0.1 degree, with an aspect knowledge of around 1 arc-minute. Rotatable solar panels enable anti-sunward pointing to coordinate with ground-based night-time observations. Two pointable high gain antennas maintain nearly continuous communication with the TDRSS. This, together with 1 GB (approximately four orbits) of on-board solid-state data storage, give added flexibility in scheduling observations.

XTE was originally designed as a exchangeable payload module for the EUVE spacecraft, but after the Shuttle service mission was cancelled, XTE was redesigned as a non-serviceable freeflyer.

RXTE was decomissioned on 5 January 2012. The decision to end RXTE's operational mission came after independent researchers in 2010 ranked the project's priority as low compared to other NASA scientific spacecraft. The 3035 kg spacecraft fell back into Earth's atmosphere on 30 April 2018.

Nation: USA
Type / Application: Astronomy, X-ray
Operator: NASA Goddard Space Flight Center
Contractors: NASA Goddard Space Flight Center
Equipment: PCA, HEXTE, ASM
Configuration: 3-Axis stabilized
Propulsion: ?
Power: 2 deployable solar arrays, batteries
Lifetime: 2 years (design); 5 years (goal); 16 years (achieved)
Mass: 3035 kg
Orbit: 565 km × 585 km, 22.99
Satellite COSPAR Date LS Launch Vehicle Remarks
XTE (RXTE, Rossi, Explorer 69) 1995-074A 30.12.1995 CC LC-17A Delta-7920-10


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