Saving the world: manned ve unmanned

[Mitchz95]

Imagine there's an asteroid that will soon hit the Earth and destroy the human race. There may be a way to divert it, but it requires launching into space a lot of complex machinery that's still fairly new and experimental. There are two options: 1) send it up in a manned ship so that there are people on site to repair anything that breaks down and/or doesn't work properly; or 2) send it all unmanned to keep the weight and mission complexity down, but risk not having anyone there to repair potential problems. Which would you choose?

[Aghanim]

Well with unmanned you could launch Orion style without those shock dampeners and slam it head on, with manned you could do this Armaggedon/Deep Impact style.

The problem is.... well it has been discussed a lot that our asteroid deflection strats are either untested or purely theoretical

And don't forget about laser arrays on the moon, gravity tractor, solar sails, all of that slow stuff that will work if our NEO trackers are online

[jwenting]

I'd hire a massive team of lawyers to battle the inevitable lawsuits by anything from environmentalists to doomsday cults that want to prevent the stuff from being launched.

By the time those are over it's too late to launch anything more than a token effort so I just launch myself and enjoy the fireworks as both the loonies and the lawyers get blown to kingdom come.

[magnemoe]

Someone called kerbal astronauts unskilled labor, they was only good for repairing wheels, unfolding solar panels and packing parachutes. Kas give them more options but not very much skilled work. Science improved this a bit.

[Nibb31]

Launching manned add several orders of magnitude in terms on complexity, and you probably won't be able to man-rate everything before we are flattened by the asteroid. If your trying something new, it's better to send a robotic mission.

[Umlüx]

but a manned mission would add flexibility. only humans can react and alter parameters quickly if the original plan fails.

[Rhidian]

Assuming that the world would unite their efforts to stave off a huge asteroid impact, why wouldn't we just send up everything we have at it? Send both manned and unmanned missions, send multiples of each, and increase the likelihood of the mission succeeding even if one part fails.

Though for the original question choosing only one, just mass produce a bunch of unmanned vehicles and throw it at the problem.

[Kerbin Dallas Multipass]

If you want to divert an asteroid you have to do it far out in space. We're talking several months travel time one way. If you do it manned that's like a Mars mission sans the lander. Huge ship, huge complexity, would probably take decades to plan, design, build.

If the asteroid is relatively close your only options are impactors and nukes. Astronauts would just be in the way.

[PakledHostage]

Though for the original question choosing only one, just mass produce a bunch of unmanned vehicles and throw it at the problem.

Attempting to divert an asteroid or comet would require technology that pushes the limits of our capabilities. I don't think it is reasonable to characterize potential solutions as something that could be "mass produced and thrown at the problem".

That said, I believe that the only realistic option currently at our disposal for diverting an object on short notice would be nuclear weapons. They have the advantage that we have a large stockplile of them and that they do not need to rendezvous with the object to work. They can be timed to detonate as they fly past. This saves large amounts of delta-V, which could make the difference between being able to use existing rocket designs or having to design and build entirely new launch vehicles.

[Idobox]

I'm all in for nukes. They are our best propulsion system, they're available, resilient, tested, easy to use. They can also lithobrake and detonate after impact, which increases thrust and breaks down the rock, increasing it's surface, which means more thrust from the next nuke, and more aerobraking if you can't push it away.

Throw as many nukes at the problem as you can until it misses you, or turns into a large number of smaller problems.