Slashdot Mirror
Lockheed Martin to Build Nuclear Powered Spacecraft
LouisvilleDebugger writes "The BBC reports that Lockheed Martin have received a $6M contract to develop the nuclear powered
JIMO, or Jupiter Icy Moons Orbiter. (According to the NASA project site, the first probes would not launch before 2011 due to development lead time.) On arrival at Jupiter, the extra power allows the probe to orbit each of three of the Galilean moons (Ganymede, Callisto, and most challenging from a radiation exposure standpoint, Europa) in turn, presumably helping to establish the possibility of liquid water and hence, life within the Jovian system. JIMO is a sub-project of Project Prometheus, initiated by NASA this year for the purpose of demonstrating that nuclear powered and propelled spacecraft may be safely designed and tested."
Project Orion was the real origin of the concept of using nuclear power in space... and while the political environment changed and didn't allow it to come to being, any of you who've never heard of it and are interested in spaceflight ought to check it out. (The link is just the first link I found on Google, there's actually a great book about it here.
I thought it was already established that water is not necessary for life.
Thomas Gold's Deep Hot Biosphere and his Book.I'm pretty sure the material is well-protected. Also, nuclear-powered space-probes have already been launched (V'ger, Viking landers too I think).
"It's too bad that stupidity isn't painful." - Anton LaVey
Nothing's completely safe. Fossil fuels aren't safe. Hydrogen isn't safe. Cows' bad breath will be the death of us all. Life is a risk-management exercise. So is designing space vehicles.
I work with some of the folks who are responsible for safety matters regarding hazardous/radioactive material aboard spacecraft. Believe me when I tell you that the utmost importance is placed on the "what-if's" of any given launch failure mode. The containers that house the radioactive material are ridiculously well scrutinized and tested, the failure scenarios are taken into consideration, including atmospheric dispersion of debris from a launch failure.
We've used plutonium powered modules for years now as a source of long-lasting (30 years or so) electrical power. Those capsules are some of the toughest, most durable, explosion-proof, reentry-proof items ever created.
For example, for one space mission, 25 sample power capsules were made for testing by using them as artillery projectiles fired by a cannon into a solid concrete wall. This induced many times the stress these capsules would ever see in even the most horrific failure of the launch vehicle. Of the 25, only one showed any sign of a stress-related crack. This tiny crack set into motion a full review of the capsule manufacturing process, a study of the atmospheric effects of a failed launch vehicle, and other safety-related processes that delayed the launch for about a year.
Whereas these newer power sources are going to be a challenge, they'll be well thought out, or they won't go.
The radiation environment at Europa is a challenge to design around. Sending the craft to Io would probably require so much more radiation shielding for the electronics (ie weight) as to make the mission infeasible.
Also, recent studies have indicated that Callisto and Ganymede might contain subterranean water, making the possibility of life greater there than at Io.
"Open the pod by doors, Hal" > "I'm afraid I can't do that, Dave" sudo "Open the pod bay doors, Hal" > alright
It looks like nobody has said this yet, so I'll pitch in -- the Cassini space probe, which was launched on October 15, 1997, was also nuclear-powered. There were protests around NASA right before the launch took place, but it went up anyway without a hitch.
According to JPL's Cassini "safety" page, they explain that the probe is powered by three radioisotope thermoelectric generators (RTGs) which provide energy by the natural radioactive decay of Pu-238. This isn't fission or fusion at work, but merely the harvesting of heat generated by the radioactive decay. The big question for environmentalists (and NASA) was whether these RTGs would remain contained in the event of a launch disaster.
The big difference between the RTGs of Cassini and the nuclear technology in JIMO is that JPL wants to have a full-fledged nuclear fission reactor this time around. This would obviously provide a lot more power for the mission, at the expense of extreme public scrutiny. It will be interesting to see how this situation pans out.
Slashdot's first reaction to VMware
Lots of spacecraft have been nuclear powered. This one will use nuclear energy to create propulsion. That's the new part.
-- Slashdot: When Public Access TV Says "No"
Voyager 1 and 2, and pretty much every other spacecraft thats every gone out beyond Mars' orbit has been powered by RTGs.
"Open the pod by doors, Hal" > "I'm afraid I can't do that, Dave" sudo "Open the pod bay doors, Hal" > alright
This has happened before. The Apollo 13 lunar module contained a plutonium power source for lunar surface experiments, which was intended to land on the moon and stay there. Instead, as we all know, the LM returned to Earth and burned up in the atmosphere after serving as a lifeboat for the astronauts. No major catastrophe.
Toronto-area transit rider? Rate your ride.
>> ...could be hard to get permision to actually launch the vehicle.Couldn't they look more into the use of solar sails rather than possibly polluting space?
Space (i.e., all that exists) is full of radiation. That's how the stars work. Some of the radiation happens to kills humans, some of it happens to keep us warm. The universe doesn't care one way or the other.
Altough a private venture says they will launch a very small sail into orbit this year, they remain untested. We have no hard proof that sails would be an effective way to travel in space. (It's worth noting that no one on Earth is using big kites as a mode of transportation.)
-- Slashdot: When Public Access TV Says "No"
It's a design study, not the building of a complete operational spacecraft.
:(
The pessimist in me says this one will be cancelled long before it ever launches
Electric Propulsion (Ion Propulsion)
Take Xenon or Krypton, use some electrical energy to ionize it, and use some more electrical energy to propel the ions out the back of your spacecraft much faster than you could ever propel the products of chemical combustion. Thus you get more momentum, gram for gram of propellant, than you would get from chemical propulsion.
Solar electric propulsion has been done before, such as Deep Space 1. But for going out to Jupiter with such a large payload, the Sun's energy is just not enough.
"Open the pod by doors, Hal" > "I'm afraid I can't do that, Dave" sudo "Open the pod bay doors, Hal" > alright
Something like this
The idea is to use something like hydrogen that when exposed to the reactor will couse great amounts of energy to be expeled useing a minimum amount of fuel
What if a volcano blasts a mountain of uranium into the air? What if your nearest coal-burning power plant releases 13 tons of uranium and thorium a year?
Actually there are two main types of nuclear propulsion...
Nuclear Thermal Propulsion (NTP) - Heat hydrogen and pass it by the reactor to heat it, then expel it.
Nuclear Electric Propulsion (NEP) - Ion propulsion, like Deep Space 1, except you have much more energy with a nuclear reactor than you would with solar arrays of a feasible size.
Both these methods are more efficient than chemical propulsion. NTP has much higher thrust than NEP, but NEP is much more efficient than NTP. So itll take longer to get where youre going with NEP, but youll use less propellant.
JIMO is using NEP, not NTP. To my knowledge, NTP has yet to be tested in space, although its been tested many times on the ground.
"Open the pod by doors, Hal" > "I'm afraid I can't do that, Dave" sudo "Open the pod bay doors, Hal" > alright
Oh, and for all those who believe that we should be designing a manned mission to Mars, let me be perfectly clear:
The only way we will get humans to Mars will be using nuclear propulsion and nuclear power sources(RTGs). Period.
And for those who question the safety of launching RTGs... this link describes the cases where this has already happened. RTGs have survived abort detonations of REAL missions right after launch with no radiation leakage. They have also survived re-entry (Apollo 13) with no leakage. The safety technology is mature and works.
This is our only ticket for orbitter missions to the outer planets.
"It takes considerable knowledge just to realize the extent of your own ignorance." - Thomas Sowell
There's more information on space-based reactors to b e used in the Jupiter mission at:
s .h tm
http://spacescience.nasa.gov/missions/prometheu
The reactor uses slightly enriched uranium, not plutonium, and is launched 'cold'. The uranium 'fuel' is much less toxic than plutonium. This type of fuel cannot be used to construct a fission bomb, as it contains far too low a concentration of U-235 to produce a nuclear explosion.
The reactor is launched 'cold', in a shut down state. That means that during launch, there will be no fission reaction products present. The reaction products are the biggest hazard with nuclear fuel, being both radioactive and chemically reactive, prone to dispersing throughout an environment if released. (Radioactive iodine and cesium isotopes being probably the best known examples.) The reactor is not started up until the spacecraft is on an interplanetary trajectory.
This is not a new technology. The SNAP-10A space reactor power system was launched in 1965. Methods for protecting and encapsulating the fuel elements to prevent dispersal or leakage are well known and tested. (These methods will survive explosions during the launch, as well as uncontrolled re-entry from orbit.)
I'm surprised nobody mentioned this yet. Considering that $6M is chump change for anything NASA does and also considering that the
NERVA nuclear rocket project was started over 40 years ago I wonder how much actual invention is going to happen here or if somebody us just going to pick up the remaining pieces of NERVA.
...is that the radiactivity and hence dose rate from a nuclear reactor is pretty negligible until it has gone critical (i.e. started) for the first time. I'm assuming this thing would be launched into earth orbit using conventional rockets (i.e. chemicals), or built in orbit, and the nuclear engine would not be started until it was at a safe distance from earth (or until escape velovity had been achieved). I imagine that at that sort of distance the gamma rays from the engine would be barely detectable from the earth's surface, if at all. Compared to what you recieve naturally from the Sun, space and the earth, that truly is a negligible amount. I was a nuclear engineer.
Stick Men
As mentioned earlier, there seems to be some confusion about what sort of nuclear power we are talking about.
There are three types of nuclear "power" sources in space.
Radioisotope power- this generates electricity because the decay of the isotope heats a thermocouple junction that generates a voltage. I'll bet this is the kind they are using on the spacecraft in question, and it has been used on many other spacecraft, including the Voyager series. Not much isotope is needed, so even if the spacecraft crashes, minimal contamination would occur.
Nuclear reactor power- another way to generate electricity in space is to have a full fledged nuclear reactor onboard the spacecraft. These designs are *very* cool. Generally they use liquid sodium as the conduction medium. Remember, mass is the determining factor in the design. To my knowledge these have never been actually used in space.
Nuclear powered rocket- the most cool rocket ever. Uses a nuclear reactor, that has hydrogen gas "fuel" running through it, superheating that gas. The gas is then ejected out the nozzle at super high speed to provide thrust. There is no electricity generation involved. As mentioned earlier, these rockets are banned by a treaty. None have every launched to my knowledge.
You should read this article called: Opening the Next Frontier. Shows, step by step how we could expand outwards into the next big frontier... Space, using nuclear powered ships.
You are in a twisty maze of processor lines, all alike.
There is a lot of hype here.