Pegasus HAPS integrated propulsion system
Pegasus Hydrazine Auxiliary Propulsion System (HAPS) is an integral liquid fourth-stage integrated propulsion system for Pegasus launch vehicles. Northrop Grumman describes a blowdown monopropellant hydrazine system with a qualified titanium propellant tank, three nominal 45 lbf Rocket Engine Assemblies, and a redundantly initiated pyrotechnic isolation valve. HAPS provides precision insertion and additional performance for higher-altitude missions; this identity represents the installed system rather than an individual engine assembly.
Identity
- Aliases
- HAPSHydrazine Auxiliary Propulsion System
- Domains
- spaceflight
- Identity Level
- integrated-system
- Kind
- integrated-propulsion-system
- Name
- Pegasus HAPS integrated propulsion system
- Status
- active
Details
- Description
- Pegasus Hydrazine Auxiliary Propulsion System (HAPS) is an integral liquid fourth-stage integrated propulsion system for Pegasus launch vehicles. Northrop Grumman describes a blowdown monopropellant hydrazine system with a qualified titanium propellant tank, three nominal 45 lbf Rocket Engine Assemblies, and a redundantly initiated pyrotechnic isolation valve. HAPS provides precision insertion and additional performance for higher-altitude missions; this identity represents the installed system rather than an individual engine assembly.
- Propellants
- hydrazine
- Rocket Specs
- Restartable
- Yes
Links
Assets & Meta
- Creation Time
- September 8, 2026 at 08:34:13 UTC
- Updated Time
- September 8, 2026 at 08:34:13 UTC
Other
- Search Name
- Pegasus HAPS integrated propulsion system HAPS Hydrazine Auxiliary Propulsion System
- Sources
- Accessed Date
- 2026-09-08
- Note
- Section 10.11 identifies HAPS as an integral liquid fourth stage and documents blowdown hydrazine, a qualified titanium tank, three nominal 45-lbf Rocket Engine Assemblies, a redundantly initiated isolation valve, and precision-insertion/higher-altitude roles.
- Publisher
- Northrop Grumman
- Title
- Pegasus User's Guide — Hydrazine Auxiliary Propulsion System
- Accessed Date
- 2026-09-08
- Note
- The assessment identifies HAPS as an optional liquid fourth stage powered by three restartable monopropellant hydrazine thrusters for higher altitude and finer orbital accuracy.
- Publisher
- NASA/FAA
- Title
- Environmental Assessment for Pegasus Launches
- Accessed Date
- 2026-09-08
- Note
- The product sheet identifies HAPS as an optional Pegasus system for precision injection and increased performance to higher LEO altitudes.
- Publisher
- Northrop Grumman
- Title
- Pegasus product sheet