Space Station Module Could Carry Humans To Asteroid

Soulskill writes "Brian Wilcox, a JPL roboticist, spoke at a NASA workshop about the possibility of detaching one of the International Space Station's modules and using it as the primary living space for astronauts on a trip to an asteroid. 'The node could be connected to two space exploration vehicles and have add-on inflatable modules. ... The space station is slated to operate through at least 2020, which roughly coincides with the earliest likely launch date for human exploration of an asteroid. In April President Barack Obama set a 2025 goal for a manned mission to an asteroid.'"

Comments

Earth return?

[MichaelSmith]

The cheapest and safest way to finish the mission would be to load the crew and samples into an apollo style capsule and reenter directly. The article doesn't describe that.

Also the module doesn't seem big enough for the centrifuge they describe. They could have a module on a boom, then rotate the whole vehicle. Perhaps the high gravity module could slide along the boom and dock with the main vehicle. If this goes anywhere I expect the centrifuge will be dropped. It is just too hard to engineer.

Re:Earth return?

[srothroc]

Rather than putting the module on a boom, I'd just put jets on the module and spin it up. You wouldn't need constant thrust, but on the down side, it wouldn't be able to put the module on the asteroid proper and you'd have to spin down for docking maneuvers.

Re:Earth return?

[sznupi]

OTOH aerobraking doesn't have to end up with immediate full reentry; some of our unmanned spacecraft performed many gradual ones when arriving at their destination (and becoming artificial satellites there), many "orbital tug" projects envisioned using aerobraking routinelly, and it is generally an extreme form of skip reentry - a good way to save on weight.

One problem could be how ISS modules are meant for long term habitation inside of Earth's magnetosphere; on deep space missions it will be good to have something built at least partially as a radiation shelter / essentially inside fuel tanks. Which presents another problem with artificial gravity - it's fairly easy when the spacecraft can be easily divided along the crewed mass vs. propulsive mass lines, not so when it's good for them to partially "mixed"...

Re:Earth return?

[QuantumG]

The designs I saw come out of this workshop, which of course are very preliminary, did indeed have direct return vehicles, but the goal is also to get the "mothership" back to Earth so that it can be used for the next asteroid mission, and the next, and the next. The goal being to develop a capability to visit asteroids of greater and greater travel time / delta-v. This is important because we don't get to choose killer asteroids, they choose us, and as the robotic missions guys said on the first day of the conference, they're all surprised they even managed to get data from their missions, and wouldn't want the fate of the human race resting on it.

And

[rossdee]

If you put wings and jet engines on a bus it would be an airliner..

Is there some specific asteroid that is going to be coming close enough to the ISS that it could be reached by detaching one of the modules?

You are probably going to need a lot of delta-v to match obits with the asteroid unless you 'visit' consists of hitting it or watching it whoosh past you at umpteen km/sec

Re:And

[QuantumG]

wow, it's such a shame you didn't go to the workshop, you could have saved us two days.

Not a bad idea

[Anonymous Coward]

There are no aerodynamics to worry about, only torsional stresses caused by the low thrust engine.

We keep thinking in terms of rockets - and clean lines - just to make it into orbit - but once in orbit that no longer matters if you don't plan to land it again.

You wouldn't be moving the pig with chemical engines, you'd be using plasma or solar sails where the forces can be measured in grams. If you want decent gravity, add a couple of outriggers and spin the whole thing - that would be a lot more force than the propulsion system will cause.

The expensive bit - getting the mass into orbit has been done, just fly up a relatively lightweight propulsion system and reuse the ISS.

O.K. the OTHER expensive bit will be food/water for a long trip, but this could do multiple missions. Park fuel/food in orbit - send a crew out for as long a loop as is deemed survivable then refuel/refill and swap crews on return.

Hell - stuff it to the rafters with food and park it above Mars for a year after a trial trip to an asteroid - no need to design an entirely new "ship" to do this - we have one we can use already. Thinking about it, no need to store water internally either, stuff it in a big plastic bag and tow it, thaw as needed.