Stargazer (aircraft)

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 for the Pegasus, a small-lift launch vehicle. As of October 2022^[update], 45 rockets (containing nearly 100 satellites) have been launched from Stargazer.^[2][3] Stargazer is the only L-1011 airframe still airworthy.^[4]

Stargazer
Stargazer in Northrop Grumman livery, carrying the Pegasus XL for the TacRL-2 mission from Vandenberg Space Force Base in June 2021
General information
Type	Lockheed L-1011 TriStar
Status	In service
Owners	Orbital Sciences Orbital ATK Northrop Grumman
Construction number	193E-1067
Registration	N140SC[1]
History
First flight	February 22, 1974
In service	1974 – present

History

The first Pegasus launch to use Stargazer was conducted on June 27, 1994, as the maiden flight of the Pegasus-XL. Previous launches used the NASA-operated Boeing B-52 nicknamed "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, the drop tests used Balls 8.

Stargazer in Orbital Sciences livery launches Pegasus carrying the three Space Technology 5 satellites in 2006

Pegasus launches using Stargazer are usually conducted from Vandenberg Air Force Base. Launches have also been conducted from the Cape Canaveral Air Force Station, NASA's Kennedy Space Center, NASA's Wallops Flight Facility and from launch sites outside the US: Kwajalein Atoll in the Marshall Islands and Gando Airport in Spain.^[5]

Orbital Sciences also offer the aircraft for research flights.^[6] It is capable of carrying a 23,000 kilograms (51,000 lb) payload to an altitude of 12,800 metres (42,000 ft).^[7]

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.^[8]

Stargazer in Orbital ATK livery, flying over the Atlantic Ocean carrying a Pegasus XL rocket

In 2015, Stargazer was repainted to reflect Orbital Sciences' merger with Alliant Techsystems. into Orbital ATK^[9]

On December 15, 2016, Stargazer successfully launched CYGNSS on behalf of NASA on its second attempt. The first attempt on December 12 was scrubbed due to issues with the hydraulic system responsible for separating the Pegasus rocket from the launch aircraft.^[10]

Stargazer appeared in Northrop Grumman livery in 2018 following the acquisition of Orbital ATK.^[11] Stargazer launched the Ionospheric Connection Explorer on October 11, 2019.

Background

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.^[12] The company also considered other aircraft including the Boeing B-52G Stratofortress, Boeing 747, and DC-10, taking into account altitude and speed performance, range, modification complexity, and acquisition and operational costs.^[13]

See also

• Scaled Composites White Knight
• LauncherOne — Virgin Galactic Rocket
• Cosmic Girl — LauncherOne Carrier Plane
• Scaled Composites Stratolaunch