Posted on 03/25/2011 12:01:39 PM PDT by LibWhacker
Propulsion in space requires the ejection of mass for an equal force in the opposite direction. Or you can capture moving mass and use that momentum.
There was even some speculation of dropping nuclear weapons out the tail and using a shield to let it push the ship.
From “Wikipedia”
“A radioisotope thermoelectric generator (RTG, RITEG) is a nuclear reactor technology electrical generator that obtains its power from radioactive decay. In such a device, the heat released by the decay of a suitable radioactive material is converted into electricity by the Seebeck effect using an array of thermocouples.”
I believe these are the power sources used on the Voyageur space-craft for instance. And we KNOW that it’s going to last till the 23rd century. You DID see Star Trek the Movie didn’t you? :-)
yes I know - the question I was trying to answer was whether there is a way to generate power from nuclear energy without H2O. There is.
Also - a better idea is the VASIMIR engine. It is an actual reality. It’ll soon be tested on the ISS.
If you (or anyone else) is interested:
Voyager 1 and Voyager 2 were launched in 1977, and are the oldest operational spacecraft. At launch, each spacecraft carried two propulsion systems, a Delta-V system, including four 100 lbf and four 5 lbf monopropellant hydrazine thrusters made by Aerojet, and an attitude control system including 16 0.2 lbf monopropellant hydrazine thrusters. The Delta-V systems have long since been jettisoned, but the attitude control systems remain operational today. The 100 lbf thrusters are the original version of the thrusters intended for Orion’s crew module and the 0.2 lbf thrusters are the original version of the thrusters currently in use for the Global Positioning System Block IIR, and are similar to those newly in service for GPS Block IIF.
Vasimr is still an ejection of mass. It is a way to to greatly accelerate the mass. But it still requires loading up the ship with mass.
I didn't claim that it wasn't. I was simply answering the question posed in #21.
“Turning a screw outside a ship”
And the above statement refers to ????
Nuclear reactor’s create heat - for transportation it’s all a matter of converting that heat energy into some form of thrust.
In an airplane a “combustion engine” (which uses heat created by the burning of a fuel) drives a turbine. Nuclear powered naval craft use the heat’s reactor to turn water into steam to drive a turbine and the turbine driving “the screw”.
But, it’s all a matter of what you do with the energy from the reactor.
A nuclear powered space vehicle might use a “nuclear electric system”, where nuclear reactors are a heat source for electric ion drives, to expel plasma out of nozzles to propel & maneuver spacecraft already in space.
Apparently NASA thinks so too and has R&D programs in the hopper, with Boeing and others, to investigate the idea.
Nuclear in any of the systems referenced do not replace the water, they replace the solar power used to heat the water.
You original comment stated:
Our modern navies seem to think, for large ocean going vessels - aircraft carriers - and vessels with trips that last a very long time - strategic submarines, that nuclear power is the best? Why would space travel be any different?
The reason space travel is different there is no medium available to exert force against. You have to take that medium with you. Most proposed systems use hydrogen or water for space travel believing those materials are likely to be replaceable in space travel.
http://www.nasa.gov/vision/universe/features/nep_prometheus.html
NEP still uses a propelant with mass. That is the ions being ejected to provide thrust.
Both of your first examples require some form of medium to travel in. Space doesn’t have enough friction in order to obtain any kind of useful propulsion.
And yes, ion drives have potential, but they haven’t been developed yet to a point where they might be used on a test flight to the moon/mars, much less as a reliable means of propulsion.
Converted into electricity for power for on-board systems. Not for propulsion. And nope, sorry, no Star Trek for me yet :p
Not to change the subject but, ... would water as a shield for cosmic radiation be practical?
I’ve seen stories discussing the problems relating to long term space travel, one big problem being dealing with shielding passengers from radiation.
Is water possibly a good answer?
Maybe but I don’t know the details.
However, if water is being used as a propelant, you probably don’t want to use it as a radiation shield since you would be consuming it.
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