Chemical propulsion systems have historically been the primary
means for transportation of payloads in space because they
generate the very large amounts of thrust required to overcome
the effect of Earth's gravity.
Technology Benefits:
- Increased performance and safety
Application of high Isp storable cryogenic propellants
to enable long-term missions in space
Accommodate extended missions without propellant losses
Advanced fuels with improved performance (increased Isp)
could minimize need for aerobraking
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| Aerojet Bi-propellant Hot-fire Test |
- Reduced propellant storage uncertainties
Reduced launch mass, or
Increased payload capability to enhance science missions
- Improve overall system efficiency (Thermal/Pressure
control)
Pressure control / venting without auxiliary propulsion
resettling
Better vehicle cooling and reduced cryogenic boil-off
Cross-benefits for other propulsion systems
- Technology Status:
Many advanced chemical propellants are being analyzed and
tested to determine their performance and applicability to
in-space propulsion. Chemical rocket systems include solid,
cryogenic liquid, and storable liquid propellants, as well
as hybrid and cold gas rockets. The number of compounds used
in the reactions typically categorizes these propellants.
Researchers are investigating ways to increase Isp, lifetime
and overall performance of state-of-the-art chemical systems.
Future Plans / Challenges:
- Advanced Fuels
Evaluate high-energy storable propellants that will
enhance performance for in space application
- Cryogenic Fluid Management
There are many aspects in the loading, storage, and
pumping of cryogenic fluids currently being analyzed and
augmented in order to improve the efficiency and safety
of handling these materials. Some of the major areas of
investigation are:
- Zero-G pressure control/Capillary Liquid Acquisition
Devices
- On-orbit Propellant transfers, including filling
the vehicle upper stage during ascent
- Liquid Mass Measurement
- Cryogenic Storage with both passive and active heat
removal
- Zero Boil-Off Tank Pressure Control
Typically, these efforts concentrate on conducting analysis,
building simulations, constructing test fixtures, building
scaled and full-size equipment, and finally verification
of the analysis and simulations through testing. The safe
and efficient utilization of cryogenic fluids for engines,
thrusters, and life support systems continues to be a
major investment area for the IISTP.
- Lightweight Components
Reducing the weight and complexity of the structures
used to carry chemical propellants is also vital in increasing
payload capabilities. Liquid propellants all require holding
vessels along with complex piping and mixing apparatus.
The combination and combustion chambers tend to be large
and heavy. Advanced materials are being developed that
will reduce the size and weight of the components, thus
directly increasing payload capability.
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