Propellant Technologies: A Persuasive Wave of Future Propulsion Benefits

Presented to the Third International Symposium on Space Propulsion in Beijing, China

Bryan Palaszewski, NASA Lewis Research Center, USA
Dr. Leonid S. Ianovski, Central Institute of Aviation Motors, Russia
Dr. Patrick Carrick, USAF Phillips Laboratory, USA

Introduction

• The World and the future
• Why propellant technologies ?
• The technologies
• Conclusions

The World and the Future

• Nations are planning many space missions
• Reusable launch vehicles are being investigated
• Low cost expendables on the horizon
• Low cost access crucial for industrial use and success in space
• Higher performance needed for far future missions
• Many technologies are available to make space access affordable

Why Propellant Technologies?

• Safety
• Operability
• Simplicity
• New capabilities are possible
• Investments in propellant have been substantial
• Lets take advantage of them

The Technologies

• Monopropellants
• Alternative Hydrocarbons
• Gelled Hydrogen
• Metallized Gelled Propellants
• High Energy Density Propellants

Why Monopropellants?

• Monopropellants offer many attractive properties
  • potentially simpler feed system
  • non-toxic
  • handleable
  • environmentally sound – good fertilizer
• Specific impulse (Isp) range of 250-290 s possible
• Additives required to deliver high end of Isp
• Large investments in technology and development made by user community for Earth-orbiting satellites: GEO and other

Monopropellant Benefits

• Monopropellants replace Space Shuttle Solid Rocket Boosters
• TEGDN/ AP /Al
• GLOW reduced
• Specific impulse (Isp) = 288 s, vacuum
• Density = 1.64 g/cm3

Propellant and Engine Testing

• Testing completed on first engines
• Many corporate, government sponsors
  • Thiokol, Allied Signal, etc.
  • NASA JSC, GSFC, LeRC, etc.
• SBIR contracts selected:
  • Catalytica, Inc.: Ignition with catalysts
  • Orbitec: Fuel and engine testing

Propulsion System Implications

• Propellant compatibility
  • Tankage, feed line materials
  • Tank liners may be required
• Ignition
  • Catalytic, laser, other
• Highly oxidizing, high temperature environment in engine
  • High water content in exhaust
  • Iridium-Rhenium (or other high temperature) chamber technology required

Alternative Hydrocarbons

• Alternative hydrocarbons provide:
  • added cooling capacity
  • density increases
  • handleability
  • improved heat transfer
  • high Mach number operation

Alternative Hydrocarbons: Airbreathing Vehicles

• Alternative hydrocarbons for Two Stage to Orbit (TSTO):
  • small increase in GLOW
  • added cooling capacity
  • high Mach number operation

Gelled Hydrogen

• Gelled hydrogen provides:
  • safety
  • density increases
  • boiloff reduction
  • specific impulse increases (in some cases)
  • slosh reduction

SSTO with Gelled Propellants

• Gelled O2/H2 (gelled H2 only)
• Payload to polar orbit
• Gelled H2 provides high payload mass
• Small payload reduction offset by reduced boiloff, slosh, and leakage

Metallized Gelled Propulsion

Metal additives are suspended in gelled fuel and they undergo combustion with oxidizer.

Oxidizer	Fuel	Metal
O2	H2	A1
O2	Hydrocarbon	A1
NTO	MMH	A1

Why Gelled Propellants?

Metallized Gelled Propellants: Past Work

• O2 /RP-1 /Al, O2 /H2 /Al, and NTO/MMH/Al are beneficial for space missions
• O2 /RP-1 /Al engine experiments: combustion, heat transfer
• Systems analyses: launch vehicles, upper stages, Lunar, and Mars
• Gelled hydrogen: with TRW – nanoparticulate gellants
• Injector testing with gelled propellant simulant,
• Propellant formulation
• Extensive historical data, current international programs

O2/RP-1/Al Liquid Rocket Booster for STS

• Payload increases of 14% possible with 55-wt% RP-1/Al (56,600 lbm)
• Small 1-ft diameter increase lifts payload to 70000 lbm
• O2/RP-1: 324 s Isp O/F = 2.7
• O2/RP-1/Al: 317 s Isp O/F = 1.1

High Energy Density Propellants: Vision

• Increased specific impulse with additives: O2/H2 baseline
  • Carbon atoms – 49 s
  • Boron atoms – 31 s
  • Aluminum atoms – 27 s
  • Hydrogen atoms – 19 s
• Additives carried in solid H2 particles
• Increase propellant and vehicle density over O2 /H2
  • More compact vehicles
• Improved payload delivery for future launch vehicles
• Predictions based on analyses and experiments of NASA and USAF

Advanced Space Transportation Program

Advanced Fuels: Research Plan

High Energy Density Propellants

Proposed Experiments

• Preliminary analyses show solid particles in cryogenic carrier fluid can carry HEDM additives to ‘conventional’ rocket combustion chamber
• Form small solid H2 in liquid helium
  • H2 particles carry HEDM additives
• Determine flow properties of solid H2 particles in liquid helium at 4 K
• Experiments are for observation and documentation of the solid-liquid interactions and flow properties
• Small scale experiments, to be conducted at NASA K-Site Facility

Conclusions

• Using improved propellants can:
  • Lower operations cost
  • Simplify spacecraft processing
  • Make space flight more accessible and affordable
  • Provide better vehicle cooling
  • Reduce cryogenic boiloff
  • Reduce vehicle structural mass
  • Reduced thermal protection requirements
  • Improve safety

Many benefits are possible, so lets do it!