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Renamed the Neil Gehrels Swift Observatory in 2018


Designation 28485 / 04047A
Launch date 20 Nov 2004
Country of origin United States
Mission Scientific: Astronomy
Perigee/Apogee 600 km
Inclination 20°
Launch vehicle Delta 2 #309

Cost: $250 million. Part of MIDEX. Managed by NASA GSFC

Will study gamma-ray burst and black holes. Gamma-ray burst have shot durations: from millseconds to minutes.

Payload provided by the US, UK and Italy.

In the first months of operation, communication delays plagued the mission. New software had to be developed to assure a better availibity of the communication channels as the satellite acts on demand (of a detected burst).

First gamma-ray burst monitored on 9 May 2005 (50 milli-seconds).

In Aug 2007, the satellite went into safe mode after gyro problems. Normal operations could be resumed with a spare gyroscope.

Went into safe mode on 18 Jan 2022, possibly due to a reaction wheel failure. Service resumed on 18 Feb.

External resources


sat-index articles

Technical data


Prime contractor General Dynamics
Platform SA-200LL
Mass at launch 1331 kg
Mass in orbit  
Solar array  
DC power 1040 W
Design lifetime 2 years

downlink: 2287.5 GHz

Within 20 to 75 seconds a gamma ray burst is detected, the satellite will automatically rotate to record the burst, the afterglow and later send back data.

Burst Alert Telescope (BAT)

With a large field (10% of the sky) of view to catch a burst and then focus.
Operates in 15 to 150 keV hard-X-ray energy range.
Built by GSFC

X-Ray Telescope (XRT)

Operates in 0.2-10 keV energy range.
Was built jointly by the Penn State University (PSU, USA), the Brera Astronomical Observatory (Italy), and the University of Leicester (UK).

UltraViolet/Optical Telescope (UVOT)

Will capture the afterglow data with an accuracy of one arc-second.
30-cm aperture telescope

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