NASA Studying Solar Powered "Space Tugboat"

Zothecula writes "Last year, NASA announced it was seeking proposals for mission concept studies of a high-power solar electric propulsion (SEP) system that could be used in a 'space tugboat.' Such a ship would be used to ferry payloads in low Earth orbit (LEO) into higher energy orbits, including geosynchronous Earth orbit (GEO) and Lagrange point one (L1) — saving on fuel and the use of expensive secondary boosters. NASA also anticipates an SEP system could be used to propel spacecraft into deep space for science missions and for the placement, service, resupply, repositioning and salvaging of space assets by commercial operators."

Comments

Sigh

[ShooterNeo]

Welcome to the 1970s? Solar panels + some kind of high ISP, extremely low thrust engine (used to be ion engines but apparently casamir effect thrusters are much better) have been planned ever since.

The problem is really simple. It's cheap to study a potential space travel mechanism on paper. But you cannot make any real progress unless real hardware is built and tested in space. And that costs a fortune, because a kilogram in space costs about $10,000 to get it there. Not to mention costs other than money, such as time and launch windows and delays and so forth.

SO...a rational person at NASA, if the organization was not at the mercy of Congress for every project, would dedicate ALL of their budget to getting that $10k/kilogram cost down to something affordable. Even if this took a large up-front investment to solve this problem.

Re:Sigh

[ShooterNeo]

SpaceX has spent less money to get actual rockets to orbit than NASA spent to build a launchpad. Perhaps privatization isn't always better, but apparently in some cases it works incredibly well. Privatizing something is a bad thing, I think, when you are essentially having government give a private entity a natural monopoly. Hence, privatizing the power grid, etc.

Re:Sigh

[AnotherBlackHat]

Ion thrusters have a distinct advantage over Casimir effect thrusters in that the former actually exist.

For LEO to HEO I think tether propulsion is a far better candidate.

Re:Sigh

[Grishnakh]

The problem with reducing launch costs is there's only a couple ways to really do that. One is to improve existing rocket tech and costs, the way SpaceX and others are doing with privatization. That might help some, but you're not going to get order-of-magnitude or better improvements out of that approach, because the laws of physics and the cost of fuel put big limits on just how cheap you can make launching that way.

The second way is to build a space elevator. Of course, we're still in the phase where people are laughing about it instead of doing it, because the idea seems too far-fetched for morons^H^H^H^H^Hlaypeople, and also because it relies on a material that's extremely new and not yet proven in industrial applications. Even with graphene or carbon nanotubes or whatever, the initial cost will still be extremely high, and you know how short-sighted humans are with economics (they'd rather pay much more over a long term than pay a big up-front cost and spend less over a long term; that's why they get loans for everything and buy subsidized cellphones).

Another way is to follow Newt's idea and build a moon base. (I can't believe I'm defending Newt here; the guy is a scumbag, but just like a stopped clock is correct twice a day, he's right about the moonbase, though I have no idea how he proposes to pay for it since he, like every other non-Paul Republican, wants to maintain giant military expenditures and start a war with Iran to boot.) With a moon base in place that has manufacturing facilities, researchers on Earth would be able to send stuff to their colleagues on the moon base to be manufactured and tested either on-site or in space. The launch cost for anything from the lunar surface would be dirt cheap compared to here, because of 1/6g gravity. Of course, that's only once you have the base in place and fully stocked with equipment, and able to mine and refine materials and energy or fuel from the lunar surface. Getting to that point will probably cost a lot more than building the space elevator (just guessing), but it can be done with present technology mostly, and would have some other additional benefits as far as providing us experience in sustaining human life off-world.

Re:Sigh

[hairyfeet]

I thought the Russians solved this problem with their Hall Effect Thrusters which they have been using in space since the early 70s? So there you have it, its proven mature tech that has been used in space and i'm sure the Russians have most if not all the bugs worked out. hell we buy many of our rocket engines from them anyway, not to mention hitch rides with them, i'm sure we can buy some HETs that will be suitable for purpose.

The really great thing about this idea IMHO is how much money we could save if we turned the ISS into basically a "space fixit shop" so that the next time Hubble or some majorly expensive sat starts malfunctioning we could have the space tug pull it up to the ISS where they could work on it instead of trying to go out to where it is and work on it there. Hell when not pulling sats maybe we can tie some sort of net or sticky material to try to clean up the massive amount of floating debris we have out there right now, making it better all around for our sats and ships.

. I'd just like to say if any NASA guys are reading this I really like the new direction you've taken. Instead of wasting tons of money on meatbags in space between the probes and ideas like this it looks like you guys are back to being the goto guys for hard science and that's just great. We probably learn more real facts from a single one of your probes than a dozen LEO trips at a hell of a lot less cost and ideas like this just shows you can still come up with some really cool ideas without them involving meatbags in space. I just hope you guys get the funding for this because the amount we could save long term if we could repair sats easily from the ISS would make this worth every penny IMHO.

A tugboat

[Osgeld]

with nothing to tug?

one would have to get shit into space for a reasonable cost before shuffling it around would be an issue

Re:maybe invent a

[Detritusher]

No need to commit suicide, just tow junk down into an unstable low orbit, leave the junk there, and then it's thrusters to boost back into a higher orbit and collect more.