Stargazer (aircraft)

From Wikipedia, the free encyclopedia
Stargazer in Orbital ATK livery, flying over the Atlantic Ocean carrying a Pegasus XL rocket
Type Lockheed L-1011 TriStar
Registration N140SC
Owners and operators Orbital Sciences
Orbital ATK
Northrop Grumman
Status Active

Stargazer is a Lockheed L-1011 TriStar built in 1974, that was modified in 1994 for use by Orbital Sciences (now part of Northrop Grumman) as a mother ship launch pad for the Pegasus launch vehicle. As of October 2022, 45 rockets (containing nearly 100 satellites) have been launched from it, using the Pegasus-H and Pegasus-XL configurations.[1][2] As of 2019, Stargazer is the only L-1011 airframe still airworthy.[3]


The first Pegasus launch to use Stargazer was conducted on 27 June 1994 as the maiden flight of the Pegasus-XL. Previous launches used the NASA-operated Boeing NB-52B Balls 8, which was also used for four subsequent launches, as the original Pegasus could not be launched from Stargazer due to clearance issues. A modified version, the Pegasus-H, was introduced to rectify this.

Stargazer was also used for captive tests and transportation of the X-34 hypersonic research aircraft; however, drop tests used Balls 8. Orbital Sciences also offer the aircraft for research flights.[4] It is capable of carrying a 23,000 kilograms (51,000 lb) payload to an altitude of 12,800 metres (42,000 ft).[5]

Orbital Sciences Stargazer departing from Vandenberg on 27 June 2013, carrying the Interface Region Imaging Spectrograph (IRIS) aboard a Pegasus XL rocket

Pegasus launches using Stargazer are usually conducted from Vandenberg Air Force Base. Launches have also been conducted from the Cape Canaveral Air Force Station, the NASA Kennedy Space Center, the NASA Wallops Flight Facility and from launch sites outside the US: Kwajalein Atoll in the Marshall Islands and Gando Airport in Spain.[6]

In 2010, Stargazer was reengined with 50,000 lbf (220 kN)-thrust Rolls-Royce RB211-524B4 turbofans to replace its original 42,000 lbf (190 kN)-thrust RB211-22Bs.[7]

Stargazer in Northrop Grumman livery carrying the Ionospheric Connection Explorer (ICON)

In 2015, Stargazer was repainted to reflect Orbital Sciences' merger with Alliant Techsystems.[8]

On 15 December 2016, Stargazer successfully launched CYGNSS on behalf of NASA on its second attempt. The first attempt on 12 December was scrubbed due to issues with the hydraulic system responsible for separating the Pegasus rocket from the launch aircraft.[9]

Stargazer appeared in Northrop Grumman livery in 2018 following the acquisition of Orbital ATK.[10] Stargazer launched the Ionospheric Connection Explorer on 11 October 2019. The launch was originally scheduled for June 2017 but was scrubbed when an anomalous piece of vehicle data was observed during a ferry flight. The data was related to the rudder position of the Pegasus XL rocket and was observed during a routine in-flight vehicle health check.[11] The launch was delayed multiple times from 2017 to 2019, finally occurring October 11, 2019.[3]


The Lockheed L-1011 TriStar carrier aircraft first flew in February 1974, and was delivered to Air Canada as C-FTNJ the following month. In May 1992 Orbital Sciences acquired the plane and had Marshall Aerospace in the UK implement accommodations for the Pegasus system. It was renamed for use as carrier aircraft for the Pegasus launch system.[11] The company also considered other aircraft including the Boeing B-52G Stratofortress, Boeing 747, and DC-10, considering altitude and speed performance, range, modification complexity, as well as acquisition and operational costs.[12]

See also[edit]


  1. ^ "Aircraft Registration Database Lookup".
  2. ^ "Pegasus". Northrop Grumman. Retrieved 2022-10-25.
  3. ^ a b Clark, Stephen (10 October 2019). "Rockets purchased by Stratolaunch back under Northrop Grumman control". Spaceflight Now. Retrieved 10 February 2021.
  4. ^ ""Stargazer" L-1011 Carrier Aircraft". Orbital Sciences Corporation. Archived from the original on 2014-04-20. Retrieved 2009-02-20.
  5. ^ "L-1011 Fact Sheet" (PDF). Orbital Sciences Corporation. 2014. Archived from the original (PDF) on 2014-04-22. Retrieved 2009-02-20.
  6. ^ Krebs, Gunter. "Pegasus". Gunter's Space Page. Retrieved 2009-02-20.
  7. ^ Norris, Guy (May 4, 2022). "Riding Along For An L-1011 Air Launch Flight Demonstration". Aviation Week Network. Retrieved 2022-10-27.
  8. ^ Ray, Justin (April 19, 2015). "Photo: New Orbital ATK paint job for Pegasus carrier jet". Spaceflight Now. Spaceflight Now Inc. Archived from the original on 2022-05-18. Retrieved 9 June 2016.
  9. ^ Kremer, Ken (December 13, 2016). "Hydraulic Pump Glitch Aborts NASA's Hurricane MicroSat Fleet Launch to Dec. 15 - Live Coverage". Universe Today. Archived from the original on 2022-01-17.
  10. ^ Granath, Bob (7 November 2018). "Stargazer Aircraft Airborne with Pegasus XL, ICON Satellite". NASA. Archived from the original on 2022-10-26. Retrieved 23 February 2021.
  11. ^ a b Bergin, Chris (August 27, 2018). "ICON resets for October launch from the East Coast". NASA Spaceflight. Archived from the original on 2021-06-23.
  12. ^ Mosier, Marty; Rutkowski, Ed (1993). "Pegasus XL Development and L-1011 Pegasus Carrier Aircraft". Utah State University Libraries. Dulles, VA: Orbital Sciences Corporation. Archived from the original on 2022-09-23.