Propulsion Research
Current propulsion use
Smart materials
Limits provided by atmosphere, weight, and reusability
Propulsion for high-speed exit of atmosphere.
Current wing design
Biomimetic Research
Wing design research
Smart materials
Wing use for descent
Geometry of dock at international space station
Geometry of dock at satellites
Using tethers for docking
Smart materials
Fine-tuned propulsion / steering for docking
Capacity for people, cargo
Weight requirements
Characteristics so can be reusable
Steering devices
Take-off and landing gear
New research indicates that a new shuttle could take off as well as land like an airplane (based on recent high-speed achievements).
No air in space, so wings and propellers useless! Also very cold, density is zero, and low pressure (could these be indicators for smart materials involving propulsion?)
Propellers produce much thrust needed for vertical lift in takeoff, while wings provide lift for horizontal movement. X-class aircraft take advantage of this.
Pathfinder airplane uses solar energy to produce electrical energy to fuel engines that turn propellers all along length of wing.
Propellers can be driven by human force (turning gears on a bicycle).
Turbines rely upon high-pressure, quickly moving gasses to produce more thrust.
Ramjet engines work as turbines do, but high-speed air is rammed into engine (for pressure), so it is ideal for high-speed aircraft but not useful in low-speed craft.
X-15 airplane uses rockets at take-off until air is fast enough to effectively make ramjet work. Then rockets disabled and ramjet works on its own.
Rocket carries all of its own oxidizer (oxygen) and fuel. Doesn't use external atmosphere, so functions in any environment.
Solid rockets must be exhausted (no turning off before fuel is gone), while liquid rockets can be stopped as needed.
Ion / Solar-Electric Propulsion: solar energy fuels electric generators that charge ions moved as high-pressure gas out of engine. Fueled with xenon, which is an abundant resource. Very slow to accelerate. 83 kg xenon gives 2.5 kW or 3.4 horsepower in one year.
Space Tethers: Spacecraft is attached to satellite or space station, which moves it about itself, then releases it appropriately, in the right new direction. If tether is conductive, as it passes through differing magnetic fields, it would create electricity. Tethers reaching into Earth's atmosphere could be used to propel objects into space or from space back to earth.
Laser / Solar Sails: Light produces force, so focussed light (lasers with lenses) could produce wind in sails. 10 gigaW laser for 16-gram vehicle.
Space elevators: A floating tower that moves in Earth's orbit could help move things from Earth to space with elevators along the tower. Would be very expensive to begin construction.
MR Fluid used for noise reduction by creating friction damper. Could be effective to quiet propulsion?
S-M Alloys have been used in smart rotor for helicopter, where rotors are easily tunable.
Airplanes have wings with several control surfaces and moving parts; new wing design uses smart materials to limit moving parts and make control surfaces only present when needed.
Wing should be straight for good lift & stability at slow speeds, then sweep back at high speeds (swing-wing design).
Area is related to lift, so high-area wings important after stability achieved (delta wing).
On rockets, no wings upon descent, just parachutes attached to the nose cone.
Fins or wings needed on rockets to help stabilize, especially early in take-off.
Biomimetics involves using natural design ideas to create product with multifunctional components.
Wing design research focuses on smooth wings and fins made of flexible materials, that can move between configurations to supply movement.
Several miniscule fliers have been created with smart materials, often based on insect flight because of great weight-lift ratio.
Smart materials respond to heat, electricity, and magnetism. They are very reliable, have low power requirements, are fast-acting, and highly controllable.
Piezoelectic Materials require input of voltage to change shape, or change of shape creates electricity. Current research uses a piezoelectric actuator to change wing and fin shape, for swimmers and wings that don't have external moving parts, are stronger, and more efficient in movement.
Shape-Memory Alloys change shape (to remembered shape) in response to temperature. Used in walking, swimming, slithering, and flying robots.
Atmosphere varies in pressure, temperature, and density with altitude. These changes could trigger change in aircraft to new wing orientations to take advantage of best modes of flight. Rotors for take-off with straight,܍
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Take off loudest
Fuel tank destroyed and rocket boosters may be damaged in parachute landing.
Weight very heavy, with all fuel stored in tanks - MAY EXCEED REQUIREMENTS.
Fuel is not environmentally friendly, reusable.
Take off requires several miles of clear space.
Traffic may be difficult to control and monitor.
Most parts reusable.
3. Rocket-style propulsion system only
Take off loudest
Most parts not reusable.
Weight very heavy, with fuel all stored in tanks-MAY EXCEED REQUIREMENTS.
Fuel is not environmentally friendly, reusable.
Traffic may be difficult to control and monitor.
Take off requires several miles of clear space.
Only nose cone reusable.
4. Aircraft-style propulsion system with "smart" wings that uses ionic propulsion at 350,000 feet
Take off loud and requires horizontal space.
Acceleration very slow.
Traffic may be difficult to control and monitor.
All parts reusable, including very sturdy ionic engine
Weight very light; ionic propulsion uses relatively light fuel(xenon & solar energy) very efficiently.
Solar power is always obtainable, environmentally friendly.
See "smart" wing pros/cons below.
5. Aircraft-style propulsion system with "smart wings" that uses sail at 350,000 feet
Take off loud and requires horizontal space.
Currently, a tremendous amount of energy is required to generate the laser to "push" the sails. This means a high weight of fuel for generating energy to make the light.
Deploying sail could be complex, error-prone procedure.
Traffic may be difficult to control and monitor.
All parts reusable (except sail?)
Weight could potentially be very light, as fuel could be harnessed solar energy.
Sail travel could be very fast.
See "smart" wing pros/cons below.
6. Aircraft propulsion system with "smart" wings that uses space tethers at 350,000 feet. Aircraft will have ionic, rocket, or sail-powered propulsion for subtle travel changes.
Take off loud and requires horizontal space.
Limited to using only previously tethered "stops", unless a means for tethering from space craft is developed.
Miscalculations from angle and time of release from tether could cause space craft to be misguided.
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