文档介绍：Cryogenic Propellant Depots Design
Concepts and Risk Reduction Activities
Future InIn--SpaceSpace Operations (FISO( FISO))
March 2, 2011
Christopher McLean
303303--939939--71337133
cmclean@
Introduction
The capability to provide on-orbit cryogenic refueling for LEO departure stages
represents a paradigm shift in the architecture required to support:
─ NASA’s Exploration program
─ Deep-space robot missions
─ National security missions
─ Commercial missions
Fuel depots enables large, beyond LEO missions without super heavy lift vehicles
This discussion covers an evolutionary approach to flight demonstrate key technologies
required for operational fuel depots:
─ Low cost Missions of Opportunity ($50M –$100M)
─ Technology Demonstration Missions (TDM’s) ($150M –$250M)
─ Flagship Technology Demos (FTD’s) ($400M - $1B)
Technology developed for these cryogenic fuel depots also increases robustness and
capacity of existing launch platforms
─ Technologies to reduce cryogenic propellant boil-off also enhance long-term (>24 hours)
storage of cryogenic propellants
─ Increases operational flexibility
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State of the Art Cryogenic Propulsion Systems
Current cryogenic propulsion stages rapidly lose residual propellant once on orbit
Studies for the Exploration EDS resulted in changing ConOps
─ Initial goal was launch with 90 day on-orbit dwell in LEO
─ Final goal reduced to 4 days due to boil-off rates, desire not to employ active cooling
─ 4 day LEO dwell results in significant system level constraints
Cryogenic boost vehicles employ Spray-on-Foam Insulation (SOFI)
─ Mitigates build up of liquid oxygen on tank external surfaces prior to launch
─ Once in orbit, provides no significant insulation capability and is a system mass penalty
Long duration cryogenic storage for LOX and LH2 demonstrated on every STS flight
─ Power Reactant Storage and Distribution (PRSD) tanks employ vacuum shells for g