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Pegasus Standard with HAPS

Pegasus Standard with HAPS added the monopropellant Hydrazine Auxiliary Propulsion System as a fourth stage to the B-52-launched Standard vehicle. Two vehicles flew, in 1991 and 1994; both reached orbit but experienced anomalies that reduced mission performance.

Pegasus Standard with HAPS
NASA Kennedy Space Center · NASA/KSC asset; NASA’s KSC-07PD-0975 catalog identifies Kennedy Space Center (KSC), credits the photograph to NASA, and describes the exact mated Pegasus XL/AIM vehicle. NASA’s current Images and Media Usage Guidelines generally permit factual or informational/editorial use with NASA attribution and without implying NASA endorsement. This image visibly includes NASA insignia and Orbital, ATK, AIM, CLASP, and U.S. marks; those logos, trademarks, and any third-party rights are separately restricted or clearance-sensitive. This credit does not grant trademark or third-party rights; verify any commercial, promotional, merchandise, or other protected-rights use. · Source
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Identity

Family Name
Pegasus
Full Name
Pegasus Standard with HAPS
Status
retired
Type
rocket
Variant Name
Standard with HAPS

Details

Description
Pegasus Standard with HAPS added the monopropellant Hydrazine Auxiliary Propulsion System as a fourth stage to the B-52-launched Standard vehicle. Two vehicles flew, in 1991 and 1994; both reached orbit but experienced anomalies that reduced mission performance.
First Flight Year
1,991
Last Flight Year
1,994
Manufacturer
Operator
Parent Vehicle Family
Propulsion Configurations
  • Entries
    • Count
      1
      Placement
      core
      Propulsion System
      Role
      main
      Stage
      first-stage
      Variant Notes
      One exact Orion 50S solid motor on the Pegasus Standard first stage.
    • Count
      1
      Placement
      upper
      Propulsion System
      Role
      upper-stage
      Stage
      second-stage
      Variant Notes
      One exact Orion 50 solid motor on the Pegasus Standard second stage.
    • Count
      1
      Placement
      upper
      Propulsion System
      Role
      upper-stage
      Stage
      third-stage
      Variant Notes
      One exact Orion 38 solid motor on the Pegasus Standard third stage.
    • Count
      1
      Placement
      upper
      Propulsion System
      Role
      upper-stage
      Stage
      fourth-stage
      Variant Notes
      One integrated Pegasus HAPS system containing three restartable hydrazine Rocket Engine Assemblies; the component count remains in the integrated propulsion identity.
    Name
    Pegasus Standard with HAPS four-stage configuration
    Notes
    Pegasus Standard with HAPS combines the Standard Pegasus Orion 50S, Orion 50, and Orion 38 solid stages with an optional integral HAPS liquid fourth stage. Northrop documents HAPS as a blowdown hydrazine system with three nominal 45 lbf Rocket Engine Assemblies for precision insertion and higher-altitude performance.
Rocket Specs
Reusability
expendable
Stages Count
4

Links

Official Url
https://www.northropgrumman.com/wp-content/uploads/Pegasus-User-Guide-1.pdf

Assets & Meta

Creation Time
July 17, 2026 at 03:02:35 UTC
Updated Time
September 8, 2026 at 08:34:16 UTC
Image
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