New Nuclear-powered Spaceship Design Revealed 285
Iddo Genuth writes "A U.S. based company introduced an
innovative propulsion system that could significantly shorten round trips from Earth to Mars (from two years to only six months) and enable future spaceships to reach Jupiter after one year of space traveling. The system, which may dramatically affect interplanetary space travel is called the Miniature Magnetic Orion (Mini-Mag Orion for short), and is an optimization of the 1958 Orion interplanetary propulsion concept."
Wrong (Score:3, Informative)
Power sources, no.
There are plenty of probes and spy satellites that are powered by plutonium-laden RTGs.
Re:Nice idea but... (Score:2, Informative)
Re:What about the surging nature of the propuslion (Score:5, Informative)
Re:Like stepping on the gas to get to Wyoming... (Score:2, Informative)
Re:What about manned? (Score:4, Informative)
2. I don't know if you understand how acceleration works. But Fewer larger explosions would make for a rougher ride. And you don't get up to speed on a day to day basis, that would be a weird way to fly a space craft.
3. 1 g constant acceleration for a few hours is pretty freaking fast. This engine could do the thrust of the space shuttle - which is more then 1 g, but why would you do 12 g for more then a few minutes?
If you do 1g acceleration for a full day you are going about After 1 day, you are going 800,000 m/s - 800km/sec or 288,000 km/hour mars is about 78million km away - so you can see how this is going, if you stop accelerating at this speed it's about a 4 or 5 million km a day just coasting, or 20 or so days to get there. So it's silly to do more then 1g acceleration, unless you are leaving a planets surface and need to reach escape velocity. So no worries about weird physical effects from the acceleration - now long term zero g is a whole'nother type of problem, but again no need to make it a long trip with this kind of power.
Jup in a Year (Score:4, Informative)
The New Horizons probe, heading to Pluto, took slightly more than a year to reach Jupiter. However, there was no need to stop (park in orbit) and it didn't need to carry bulky life-support stuff. Thus, it could take the fast train.
Cassini (Score:5, Informative)
Re:That's nothing.. (Score:5, Informative)
I remember that there was some talk of actually launching a small probe based on the concept, but apparently the plan was scrapped. (Probably to help fund manned space travel.) Whatever antimatter confinement technologies they were working on may have led to the development of this new magnetic confinement fission technology. Or it could just be a coincidence.
Either way, nuclear technology of this sort is fairly well developed and is not a pipe dream. At least not from an engineering standpoint. Getting the risk adverse US Government and NASA to actually build one of the many known-quantity engines we have on hand is a completely different ball of wax. They're still trying to get us reliable LEO access (Thank God for Griffin is all I can say), so I doubt we'll be seeing any advanced engines in practice until the CEV/Orion project enters its third phase.
Comment removed (Score:3, Informative)
Blog troll. Link to real info here. (Score:5, Informative)
First, this is a blog troll, to drive traffic to some ".info" site. The actual paper, "Proposed Follow-on Mini-Mag Orion Pulsed Propulsion Concept" [aiaa.org] presented at an AIAA conference last year, is more useful.
The basic idea is to create a small fission (not fusion) explosion using magnetic compression. Nuclear weapons use chemical explosives to create an implosion, and during the implosion the fissionable material is compressed hard enough to get a 1.5x to (maybe) 2x density increase. With magnetic compression, a small pellet can be compressed hard enough to get a 10x density increase. This allows smaller explosions, around 50 gigajoules instead of the 20 terajoules of a fission bomb. They want to use curium or californium as the fuel, rather than plutonium.
They also want to use magnetic containment, rather than an Orion-style "pusher plate" sprayed with oil. Unclear if that can be made to work.
The experimental work (they compressed an aluminum cylinder with a big magnet at Sandia) was done back in 2002. This isn't really under active development.
It's not a totally unreasonable idea, but it would be a huge job to make it work. For one thing, the plan is to assemble a large spacecraft in orbit, not to take off from Earth. It doesn't help with the problem of putting mass in orbit.
Re:Nice idea but... (Score:4, Informative)
There has been research into nuclear rockets (NERVA) [wikipedia.org], and nuclear power sources.
Project Prometheus [wikipedia.org] shows promise. Already, most of the long range probes that NASA has use radioactive decay as a power source, which is pretty safe and reliable.
Re:What about manned? (Score:4, Informative)
Also, it is not an explosion, but rapid combustion.
Further, the magnitude of the events is quite different
( in a car engine, the events are relatively small,
on orion, well, bigger ).
Re:Not like old Orion (Score:5, Informative)
I'm more worried about Strontium 90 and radioactive iodine.
Given that Hanford deliberately released a BUNCH of radioactive iodine upwind of an indian reservation at least partly to see what its effects would be on the "marginal population" of indians and rednecks downwind (leading to a considerable increase in birth defect constelations and graves' disease), I suspect others are with me on that.
Re:What about manned? (Score:5, Informative)
Anyway, a 100 metric ton craft would be pretty wimpy. That's 5% of the Space Shuttle's mass, for instance. I suspect this would be an unmanned mission. (For reference, the Apollo Service Module & Lunar Module together were about 40 metric tons and the longest Apollo missions only lasted 12 days).
Also, the 'ignition mass' for the fastest version would be a whopping 1300 metric tons of plutonium. Using uranium prices as a stand-in, that's about $300 million in fuel. That's an awful big price tag for just getting a larger probe to Mars faster.
Re:Blog troll. Link to real info here. (Score:5, Informative)
Ought to be a cake-walk once they've got the field in place to make it go "bang".
The pellet is ALREADY confined in a mag field. The re-expanding plasma from the explosion dumps much of its energy into compressing the field between the plasma and the conductor that created it, making the field stronger (and dumping a bunch of the energy back into the conductor as electricity for potential reuse or consumption).
Should be easy to create a selective leak in the desired direction and more fields to guide the plasma as it makes its getaway. (In fact the compressed field toward the vehicle can be used as a spring to return some of that collected energy to the plasma, further increasing the exhaust velocity. And/or the energy from the compressed field could be used to create or strengthen the "nozzle" guiding fields, just-in-time to guide the burst of plasma.)
Lots of opportunity for cute electric/magnetic/plasma engineering tricks here.
And unlike fusion the time scale, from ignition to completion of the exhaust cycle, is short, so plasma instabilities aren't an issue.
Re:Cassini (Score:4, Informative)
When not using solar panels (conspicuous and vulnerable) Americans like to power their satellites with RTGs. The Soviets put 35 reactor-powered satellites in orbit and only a few RTG-powered satellites. What was forbidden by the treaty was nuclear weapons, specifically including tests. An interstellar spacecraft powered by nuclear explosions would be a great way to sneakily test your weapons in full view of everyone.
Re:That's nothing.. (Score:5, Informative)
Orion has already been obsoleted by a similar (but much more effective) design using normal-sized nuclear explosions -- Medusa [wikipedia.org]. Medusa reverses the Orion design, having a parachute in front towing the craft, and detonating the explosives in front of the parachute. It uses structures in tension instead of compression (lighter), it allows the explosions to be further from the craft (less radiation), allows a longer acceleration stroke (smoother acceleration), and captures a larger percentage of the explosive energy.
Re:Reduces travel time how? (Score:3, Informative)
I prefer a holtzman Transfer. Get there in 0.01s. Only bad thing is no one knows how it works except god and Holtzmans wife. And God help you if you bring a laser pointer.
Andrews Space (Score:3, Informative)
From my (admitted limited) viewpoint as an (inexperienced) aerospace engineer, they look like the real thing.
The system is actually described in a 2003 AIAA conference paper linked on this page [andrews-space.com]. The paper is titled "Mini-MagOrion: A Pulsed Nuclear Rocket for Crewed Solar System Exploration [andrews-space.com]."
I've only glanced over the article so far, but it suggests specific impulses in the 10,000 seconds plus range. That's a critical measure of efficiency in a rocket that dictates the velocity it can obtain. The shuttle's SSMEs get about 455 seconds of specific impulse at a high thrust (millions of Newtons) and ion drives, like the one on the DS1 probe, and the like get specific impulses (Isp) of about 3000 seconds at low thrust. (millinewtons). Apparently the Mini-Mag Orion can produce thrust on par with the SSME. Yikes.
--sabre86
Re:What about manned? (Score:2, Informative)
The word is damp. The infinitive is "to damp" and a device which damps is a damper. There's no need for the extra -en unless you want to have a confusing half-synonym for moisten.
On an orion, the pusher plate is connected to the main spacecraft body by shock absorbers. Quite similar to a gun recoil mechanism, I imagine, except that for manned flight it would spread the impulse out over a much longer time period. Timed just right, occupants of a habitat at the top of the structure would experience constant acceleration.
The main problem with Orion is that it doesn't solve a problem that exists. It has less Isp than some of the better electric propulsion options, and huge structure requirements. It is high thrust, high Isp, so it's main use would be getting off the planet, but its nature contraindicates ever being used within the atmosphere.
Re:What about manned? (Score:4, Informative)
The word is damp. The infinitive is "to damp" and a device which damps is a damper. There's no need for the extra -en unless you want to have a confusing half-synonym for moisten.
(from dict.die.net)
Source: Webster's Revised Unabridged Dictionary (1913)
Damp \Damp\, v. i. [imp. & p. p. Damped; p. pr. & vb. n.
Damping.] [OE. dampen to choke, suffocate. See Damp, n.]
2. To put out, as fire; to depress or deject; to deaden; to
cloud; to check or restrain, as action or vigor; to make
dull; to weaken; to discourage.
Source: Webster's Revised Unabridged Dictionary (1913)
Dampen \Damp"en\, v. t. [imp. & p. p. Dampened; p. pr. & vb.
n. Dampening.]
2. To depress; to check; to make dull; to lessen.
Dampen \Damp"en\, v. i.
To become damp; to deaden.
Re:Didn't we (Score:2, Informative)
http://dialog.newsedge.com/newsedge.asp?site=2006121916143901110346&block=folderstory&briefs=off&action=XMLStoryResult&smd=true&storyid=p0906509.2rw&rtcrdata=off [newsedge.com]
Also same site was touting anti-matter proplusion last year http://www.tfot.info/articles/33/new-antimatter-engine-design.html [tfot.info]
Also - do we really want to do fission - its so 20th century and dangerous - news today - The UK has built up a stockpile of 100 tonnes of plutonium - enough to make 17,000 nuclear bombs http://news.bbc.co.uk/1/hi/sci/tech/7006056.stm [bbc.co.uk]
Re:hopefully (Score:3, Informative)
The Orion concept is much more technically feasable, barring any massive breakthroughs in materials and fusion power.
Re:Wrong (Score:3, Informative)
Not even close.
Go read some books about who was involved with the Orion designs, when those plans were put together and when the "reduce stockpiles" movement started -- you'll see how ridiculous a statement that is.
Re:Reduces travel time how? (Score:2, Informative)
Hohmann transfers are used because feeble chemical propulsion cannot produce the delta V required for a quicker transfer orbit.
Atomic Rockets [projectrho.com]
At the other end of the spectrum of transfer orbits are Brachistochrone trajectories [projectrho.com]. When the propulsion system becomes powerful enough to produce delta Vs higher than about 10 km/sec, you can treat the planets as being essentially stationary, that is, they will not move appreciably in the short time required for transit.
Re:Blog troll. Link to real info here. (Score:2, Informative)
The basic idea is to create a small fission (not fusion) explosion using magnetic compression. Nuclear weapons use chemical explosives to create an implosion, and during the implosion the fissionable material is compressed hard enough to get a 1.5x to (maybe) 2x density increase. With magnetic compression, a small pellet can be compressed hard enough to get a 10x density increase. This allows smaller explosions, around 50 gigajoules instead of the 20 terajoules of a fission bomb. They want to use curium or californium as the fuel, rather than plutonium.
The experimental work (they compressed an aluminum cylinder with a big magnet at Sandia) was done back in 2002. This isn't really under active development... It's not a totally unreasonable idea, but it would be a huge job to make it work.
Good post.
To expand upon it a bit, I will observe that actual pressures and compressions demonstrated so far are maybe a couple of orders of magnitude below what is needed to achieve 10-fold compression of fissile material. They demonstrated pressures of 2.4 megabars (atmospheres) and roughly two-fold compression in aluminum, performance generally similar to what high explosive implosion systems have produced for over 50 years. Despite decades of work, HE implosion has never been scaled to the pressures or compressions postulated for this. See: APS [aps.org] and AIP [aip.org] pages on this.
Now, their ace-on-the-hole is that they can achieve isentropic compression (i.e. optimal compression, without heating) explosive systems cannot, but even so they aren't in the ball-park with this, only looking at it with binoculars. And the Z-machine is a huge immobile installation. How to convert a grossly souped up version of it to practical flight-ready hardware would be a staggering task.
So this is in the same league as commercial fusion power. A concept that has some grounding in reality, but possibly one forever beyond practicality, and certainly beyond the working career of any living engineer.