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Fri Jan 11, 2019, 03:45 PM

Steam-propelled spacecraft prototype can theoretically explore celestial objects "forever"

From phys.org:




Using steam to propel a spacecraft from asteroid to asteroid is now possible, thanks to a collaboration between a private space company and the University of Central Florida.

UCF planetary research scientist Phil Metzger worked with Honeybee Robotics of Pasadena, California, which developed the World Is Not Enough spacecraft prototype that extracts water from asteroids or other planetary bodies to generate steam and propel itself to its next mining target.

UCF provided the simulated asteroid material and Metzger did the computer modeling and simulation necessary before Honeybee created the prototype and tried out the idea in its facility Dec. 31. The team also partnered with Embry-Riddle Aeronautical University in Daytona Beach, Florida, to develop initial prototypes of steam-based rocket thrusters.

"It's awesome," Metzger says of the demonstration. "WINE successfully mined the soil, made rocket propellant, and launched itself on a jet of steam extracted from the simulant. We could potentially use this technology to hop on the Moon, Ceres, Europa, Titan, Pluto, the poles of Mercury, asteroids—anywhere there is water and sufficiently low gravity."

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Reply Steam-propelled spacecraft prototype can theoretically explore celestial objects "forever" (Original post)
Jim__ Jan 11 OP
hlthe2b Jan 11 #1
brush Jan 11 #2
Jim__ Jan 11 #3
struggle4progress Jan 13 #6
muriel_volestrangler Jan 12 #4
MineralMan Jan 13 #5

Response to Jim__ (Original post)

Fri Jan 11, 2019, 03:47 PM

1. I took physics in college and did very well, but this is baffling to me. Highly intriguing, though.

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Response to hlthe2b (Reply #1)

Fri Jan 11, 2019, 03:55 PM

2. Puzzling is right, especially the part about going to Mercury. Water on Mercury?

And wouldn't it burn up if it tried to find water there?

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Response to brush (Reply #2)

Fri Jan 11, 2019, 04:10 PM

3. NASA does believe there is ice at the poles of Mercury.

Nasa:Water ice on mercury

Of Interest: This orthographic projection view provides a look at Mercury's north polar region. The yellow regions in many of the craters mark locations that show evidence for water ice, as detected by Earth-based radar observations from Arecibo Observatory in Puerto Rico. MESSENGER has collected compelling new evidence that the deposits are indeed water ice, including imaging within the permanently shaded interiors of some of the craters, such as Prokofiev and Fuller. The MESSENGER spacecraft is the first ever to orbit the planet Mercury, and the spacecraft's seven scientific instruments and radio science investigation are unraveling the history and evolution of the Solar System's innermost planet. In the mission's more than four years of orbital operations, MESSENGER has acquired over 250,000 images and extensive other data sets. MESSENGER's highly successful orbital mission is about to come to an end, as the spacecraft runs out of propellant and the force of solar gravity causes it to impact the surface of Mercury in April 2015.

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Last Updated: Aug. 6, 2017
Editor: Tricia Talbert

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Response to brush (Reply #2)

Sun Jan 13, 2019, 06:16 PM

6. Mercury's day lasts about twice as long as Mercury's year,

and while midday equatorial temperatures are around 800F, midnight equatorial temps are around -300F. The poles, meanwhile, stay around -140F

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Response to hlthe2b (Reply #1)

Sat Jan 12, 2019, 02:50 PM

4. My guess is they make hydrogen peroxide and use that as fuel

See eg https://en.wikipedia.org/wiki/High-test_peroxide

They could even be making hydrogen and oxygen, but that must be harder to handle, I'd think. Doing it on a cold asteroid might help, though. It does look like it's more than just using the water as reaction propellant in an ion engine, however:




You'd need a good thrust to get off the Moon, Mercury etc. - more than an ion engine could manage so far, I think.

On edit: No, it seems they just pressurize the steam:

The World is Not Enough (WINE) is a new generation of CubeSats that take advantage of ISRU to explore space for ever. The WINE takes advantage of existing CubeSat technology and combines it with 3D printing technology and a water extraction system developed under NASA SBIR, called MISWE . 3D printing enables development of cold gas thrusters as well as tanks that fit perfectly within the available space within the CubeSat. The MISWE allows capture and extraction of water, and takes advantage of the heat generated by the CubeSat electronics system. The water is stored in a cold gas thruster's tank and used for propulsion. Thus, the system can use the water that it has just extracted for prospecting to refuel and fly to another location. This replenishing of propellants extends the mission by doing ISRU (living off the land) even during the prospecting phase. In Phase 1, we plan to test and investigate critical technologies such as (1) sample acquisition, (2) volatiles capture, and (3) 3D-printed cold gas thrusters that use water vapor including the organic and particulate contaminants that are inevitable during the early stages of asteroid mining. The engine is similar to a Solar Thermal Engine but scaled for a CubeSat.

https://www.sbir.gov/sbirsearch/detail/887413

A cold gas thruster is a propulsive device that uses pressurized inert gas as the reaction mass. The compressed gas is released through a propelling nozzle to generate a cold jet thrust.[1]

A cold gas thruster usually consists of simply a pressurized tank containing gas, a valve to control its release and a propelling nozzle, and plumbing connecting them. A very simple example would be the use of a handheld CO2 or nitrogen gas fire extinguisher while sitting down in a rolling office chair; motion is achieved by pointing the nozzle in the direction opposite of the desired movement and activating the extinguisher.

Because the gas is usually unheated, speed at the throat is low and very low performance is achieved; in a vacuum with nitrogen gas a specific impulse of 73 seconds can be achieved.[1] The maximum theoretical specific impulse for nitrogen gas is 76 seconds. In the simplest approximation, the specific impulse is modeled as proportional to the square root of the (absolute) gas temperature, so performance rises as the gas temperature is increased. A thruster in which the performance is increased by heating the gas by an electrical resistance is known as a resistojet.

Cold gas thrusters are mostly useful for vernier engines, and are employed chiefly for simplicity and reliability.

https://en.wikipedia.org/wiki/Cold_gas_thruster




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Response to Jim__ (Original post)

Sun Jan 13, 2019, 02:27 PM

5. Steampunk Spaceships. Oh, My!

Who knew?



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