- 2982 - SATELLITE - steam powered? Engineers have developed the specifications for “CubeSat” technology that will use steam as a propellant. Many CubeSats experiments have been held back until now because of a lack of good propulsion technology that small satellites can use.
----------------------------------- 2982 - SATELLITE - steam powered?
- When I was growing up in a small town my Dad would take me along to visit all these “uncles“. I meant at least 6 families that had taken him in when he was an orphan. His Dad died in a trolley car accident. He was on top of the bus trying to reconnect the beam to the electric wires overhead.
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- That was old technology and my son has my Grandpa’s correspondence course that he was taking trying to learn electrical engineering. Here we are 100 years later and we are considering a “steam powered” satellite to do work in orbit. Steam driven cars existed in Grandpa’s era. Now we have steam driven satellites. Go figure!
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- A “Steampunk Engine” will be used to solve many of our satellite problems . Engineers have developed the specifications for “CubeSat” technology that will use steam as a propellant. Many CubeSats experiments have been held back until now because of a lack of good propulsion technology that small satellites can use.
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- With the proliferation of small satellites Low Earth Orbit (LEO‘s) has become overcrowded. Thanks to a breakthrough engine design, the “ThermaSat‘, that utilizes steam to generate propulsion, all of that could change very soon.
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- Of all the estimated 2,700 CubeSats and other “nanosatellites” that have been created to date, less than 10% have had their own means of propulsion. This leaves them at the mercy of gravity and atmospheric drag, which can cause them to de-orbit while they are still functional. In addition, they are unable to maneuver and adjust their orbit and get out of the way of other satellites and space debris.
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- These small satellites require substantial power to operate, siphoning energy from the primary payload. There are the more ‘energetic’ propulsion systems that are typically scaled down from use on much larger satellites. These rely upon toxic, highly pressurized or even explosive liquids, such as hydrazine.
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- This is a problem as most CubeSats share a ride to orbit and launch providers are leery of endangering their other, often more valuable cargo. While deployment from the International Space Station, which is common for CubeSats, precludes any satellite propulsion which likewise might pose a risk to the station and personnel.
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- The “ThermaSat steam engine” overcomes these obstacles. While the propellant is plain water, ThermaSat differs from conventional steam engines by relying on solar power. This is provided by an exposed optical surface on the unit’s capacitor, rather than bulky, protruding reflectors, that turn the water into superheated steam an instant before it is shot out the rear nozzle.
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- The engine also has the benefit of being compact and lightweight and consists of only two moving parts. It can deliver 1,800 Newton-seconds of total impulse , or 203 lbs/s of specific impulse, using just 2.2 lbs of propellant about the size of a 4 cup teapot. This is enough to maintain a CubeSat at an altitude of 233 miles for more than five years and at altitudes as low as 155 miles for several months.
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- Without propulsion, the orbit of a CubeSat at 155 miles altitude would decay in a matter of weeks. By being able to sustain such orbits over longer periods of time, small satellites could provide higher-resolution remote sensing and decreased communications latency, which could come in handy in the event of a natural disaster or crisis.
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- A satellite equipped with the ThermaSat could even alter its orbit to get a better look at a situation in progress.
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- The heart of the system is the unique thermal capacitor, made from phase-changing materials, which concentrates and stores the solar heat collected from just 20 square inches of exposed surface area.
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- Using a combination of photonic crystals and gold-tinted mirrors the completely inert capacitor reaches a blistering operating temperature of 1,433 Fahrenheit. This results in a specific energy comparable to a lithium-ion battery, but without the potential for explosion.
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- The system has a dry weight of 3.2 lbs and 5.4 lbs when fully-fueled. It is capable of supporting standard configuration CubeSats. It can generate as much as 656 feet / second of acceleration (delta-velocity) and requires 2.3 to 4.6 Watts of electrical power provided by solar panels.
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- The ThermaSat can be used to raise orbits, for geolocation missions which require formation flying as well as for scheduled de-orbiting and collision avoidance that will likely to become a requirement.
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- Since it requires no power from the satellite, the ThermaSat can be used to upgrade larger satellites with an additional propulsion unit. The greatest asset of the “steampunk” engine is the way it can enable a new class of smart, autonomous satellites able to relay data and even to ‘swarm’ together for specific tasks.
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January 15, 2021 2982
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