NASA aims for space tests of Mars-in-a-month plasma drive

VX200?

Is that a sporty Vauxhall?

Kill all Greens, get the Techno rolling!

You know, when I was at uni and talked about nukes in space, other so-called "engineers" would decry the danger of "nuclear pollution of space". I had the terrible urge to bash in heads with a fire axe.

"The fact is that even the launch of comparatively simple and low powered radioisotope-decay power units (as opposed to reactors proper) often draws a lot of technofear protest"

Frack. That. Shit!!

"and the bureaucracy and expense associated with spaceflight-rated nuclear technology is immense."

Cut the red tape! Drop the regulatory horror! If need be, launch Doctor-No like from dead volcanoes in Zimbabwe or other cash-strapped places. They will be forgiving.

I must be missing something

Are they talking about using a solar array to power this thing to Mars? Because I'm thinking a big sail travelling at a very high speed isn't going to cope well with any debris it encounters along the way.

200kW ??

I'm currious as to where exactly the 200kW will come from on the ISS. To my understanding there is only 110kW user power available, and you would have to turn off everything to get all of that. I don't think that using all the solar array juice and not charging the batteries counts; the next 45 minutes without power would leave the ISS pretty dead. (Normally in sunlight half the array power charges the batteris for the next eclipse)

Maybe the reason that this thing is car-sized if because it carries it's own juice as well as gas? The ones around here (although lower power) are more like the size of a remote controlled car rather than full-sized one.

Oh YES!

it *is* rocket science... :o)

A note on Argon, nuclear reactors in space and alternative power sources.

IIRC Xenon has been the preferred fuel for ion engines in space. It's *much* easier to store than Helium (the smallest atom) and being larger than Argon *should* be easier to ionize.

However while Argon is likely to be harder to ionize (higher voltage power supply needed) it is also the most *common* noble gas in the atmosphere and perhaps most important of all, the *cheapest* as it's used in welding quite a lot.

Being cheap and readily available (I'd expect large welding supply stores to have at least some in stock) can pay dividends when your research is on a budget.

The problem with nuclear reactors in space (at least those in the *open* literature) is that they just are not *big* or current enough. The last *actual* US orbiting *reactor* was SNAP-10A in 1965, which was good for about 500W.

The proposed SP100 (100Kw) for SDI in the early 80's never got out of design. Los Alamos has been designing something called the SAFE400, designed to deliver 100Kw of electrical power, as a sort of private project of the director, and that's about it in the US (of course the NRO, USAF and USN *could* have one on every big sat they've been orbiting since the 80s and simply not *told* anyone. However the presence of high temperature neutron emitting IR sources *anywhere* in Earth orbit would be a pretty big hint *someone* was using them and the list of countries that could is a short one).

The US bought 6 TOPAZ reactors in the early 90s (and AFAIK still has them) but I don't think they bought any *fuel*. However even if they were good to go they would deliver about 5Kw

each.

Bottom line. No one is going to design, build and qualify a space nuclear reactor in the timescale needed (although a space reactor design in the 100Kw+ range, which gave more power than all but the *biggest* solar arrays, *would* be a good idea to have on the shelf for the future)

Ground based turbo generators in the 200Kw range are used for emergency power and typically fueled by gasoline or natural gas. Assuming sea level air has a density 1.22521 kg/m3. and 20% of that mass is O2 then LOX is 4562x more dense (per cubic metre). It *should* be possible to build a power pack (LOX/fuel tanks, turbo-generator, controls) into a package you could stow on the Shuttle.

While it would be enough to *start* the engine it's *very* doubtful to get the kind of run time that would be needed to show up any flaws that *only* shoe up in long term tests (936 Hrs, possibly with a re-start following flip over at the half way mark if you really want to go to Mars)

BTW the way to avoid the exhaust interfering with the thrust measurements is to fit the exhaust pipe with a T end piece that exhausts in equal and opposite directions, canceling any thrust.

Wiring this thing *directly* to the ISS power system and directly mounting it to the structure is *much* the simplest option.

Electromagnetic Shielding?

The extra exciting part, is the very large magnetic fields generated by the engines' super conducting magnets.

I wonder if these could be used to provide an artificial magnetosphere for shielding the crew on long duration manned voyages.

The engines also generate a magnetic torque that perhaps could be used to rotate the crew capsule creating a centripetal force to create artificil garvity.

Solutions to two long-duration flight travel problems as a result of a by-product!

mass in space

... multiplied by speed turns to inertia, which must be preserved (unless opposite ... etc).

So it does matter, only differently.