Family: Pegasus
Pegasus XL
Launch statistics
- 46
- Launches (as of July 27, 2026)
- 1
- Successes
- 0
- Failures
- 100.0 %
- Success rate
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The Pegasus XL is the stretched configuration of Pegasus, the air-launched small-lift vehicle developed by Orbital Sciences Corporation and later built and operated by Orbital ATK and Northrop Grumman. It is not a separate rocket but a version of Pegasus with lengthened first and second stages — the motors become the Orion 50SXL and Orion 50XL — to increase performance; the upper stages are unchanged and flight operations are similar. The wing was strengthened slightly to handle the added weight. Pegasus was the world's first privately developed orbital launch vehicle. Rather than lifting off from a pad, the rocket was carried beneath a mother ship — initially a NASA B-52, and from 1994 the L-1011 TriStar 'Stargazer' — and released over open ocean at about 40,000 feet; after five seconds of free fall it ignited its first stage. That first stage had no gimballed nozzle and was steered by a delta wing and fins. The vehicle comprised three solid-propellant stages plus an optional fourth hydrazine monopropellant stage, the HAPS module. Pegasus is retired. Able to carry up to about 450 kg to low Earth orbit, it flew mainly scientific satellites for NASA. Demand fell sharply in the late 2010s as small satellites migrated to rideshare slots on larger rockets, and the programme closed in 2026 after 46 missions.
History
A private rocket with wings
The project began in the spring of 1987, funded entirely by Orbital Sciences Corporation and Hercules Aerospace, with no government money for development. The team was led by Antonio Elias; the wing and fins were designed by Burt Rutan and his company Scaled Composites. The three Orion solid motors were created specifically for Pegasus, drawing on carbon-fibre, propellant-formulation and case-insulation technologies from the terminated Small ICBM programme. The first flight, with no prior test launches, took place on 5 April 1990 from a NASA B-52. In 1991 the team received the U.S. National Medal of Technology.
Enter the XL
The Pegasus XL was introduced in 1994 with its lengthened stages. Its debut, on 27 June that year with the STEP-1 mission, ended in failure: the vehicle lost control 35 seconds into flight and range safety commanded flight termination at 39 seconds; the likely cause was improper aerodynamic modelling of the longer version. Across its life the programme suffered three mission failures and two partial failures, followed by thirty consecutive successful flights, for an overall success rate of 89 percent. The standard version was eventually discontinued, leaving the XL as the only configuration in service.
Commercial decline
The initial offered price had been US$6 million, without options or the HAPS manoeuvring stage, but it rose with the move to the XL and with the additional services customers typically buy. NASA's ICON mission, finally launched in October 2019, carried a total cost of US$56.3 million. Between 2016 and 2026 the Pegasus XL flew only three times: 2019, 2021 and 2026.
Final flight
In November 2025 Katalyst Space Technologies selected Pegasus XL for a rescue mission to NASA's Neil Gehrels Swift Observatory, intended to prevent an uncontrolled re-entry. The mission required a low-inclination orbit not served by common rideshare launches and beyond the performance of smaller dedicated rockets. The flight, conducted on 3 July 2026 from Kwajalein Atoll, used the last Pegasus XL in Northrop Grumman's inventory and closed the programme's history.
Launch timeline
| Date | Launch site | Outcome | Payload |
|---|---|---|---|
| Jul 3, 2026, 8:36 AM | Kwajalein Atoll | Success | Contracted by NASA under the Small Business Innovation Research Phase 3 contract, Katalyst Space Technologies' LINK servicing spacecraft will rendezvous and attach to NASA’s Neil Gehrels Swift Observatory to re-boost its orbit. This aims to demonstrate a key capability for the future of space exploration and extending the Swift mission’s science lifetime in gamma ray astronomy. |
Versions
| Pegasus Standard | Pegasus/HAPS | Pegasus XL | Pegasus H | Pegasus XL/HAPS | |
|---|---|---|---|---|---|
| First launch | April 5, 1990 | July 17, 1991 | June 27, 1994 | April 3, 1995 | December 23, 1997 |
| Last launch | August 3, 1994 | May 19, 1994 | July 3, 2026 | October 9, 2000 | April 15, 2005 |
| Height | 16.9 m | — | 17.6 m Best value in this row | — | 17.4 m |
| Diameter | 1.3 m Best value in this row | 1.3 m Best value in this row | 1.3 m Best value in this row | 1.3 m Best value in this row | 1.3 m Best value in this row |
| Mass | 18,500 kg | 18,500 kg | 23,130 kg Best value in this row | 18,500 kg | — |
| Liftoff thrust | 500 kN | — | — | — | 726 kN Best value in this row |
| Stages | 3 Best value in this row | 4 | 3 Best value in this row | 3 Best value in this row | 4 |
| LEO capacity | — | 250 kg | 443 kg Best value in this row | 350 kg | 350 kg |
| Reusable | No | No | No | No | No |
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