# Is it possible for a human to walk on an asteroid?

"We’ll start by sending astronauts to an asteroid for the first time in history"
(President Barack Obama on Space Exploration in the 21st Century".)

With a very low gravity, an asteroid is not really friendly to the walking visitor. Any movement may send the walker back to orbit.

Considering the schedule -- NASA could launch a mission as soon as 2025, -- a solution will need to be validated by less than 10 years.

What kind of solution is foreseen by NASA to keep astronauts on the asteroid ground when collecting asteroid samples or performing other useful activities?

Related: How will they mine asteroids?

Not a duplicate of Could a Human reach escape velocity by jumping from the surface of Ceres (a dwarf planet)?, I'm not asking if astronauts can reach escape velocity (which is possible), but what solutions are currently foreseen to perform activities in an efficient way for the missions planned by NASA "as soon as 2025".

• Bring along your climbing gear. ;) Apr 23, 2015 at 21:32
• Yeah, technique would be quite a bit different. But so would be the landscape. I'm sure you could find two or more places to hook to and then traverse the rope like a spider. Or something along those lines. Pardon the pun. No need to hammer bolts in, you could use grappling hooks, L, T inserts, bore holes with a drill to lay bolts in, cement cracks, use expanding foam glues,... many things could work in a low gravity and vacuum environment with not much strength needed for forces involved. :) Apr 23, 2015 at 21:39
• Maybe an astronaut could pick up and carry a huge boulder to get useful weight? Apr 24, 2015 at 9:17
• @LocalFluff: Remember that weight and inertia are two different things. If the astronaut carried enough mass to create useful weight, s/he would find it virtually impossible to start & stop, or change direction once moving. Apr 24, 2015 at 20:19
• Sep 8, 2018 at 23:50

It depends on the size of the asteroid. According to this article, if the asteroid's diameter is more than 8 km, you can walk on it without the fist step sending you flying off.
When the asteroid is smaller, the article proposes to loop a cable loosely around the asteroid. Astronauts can tether themselves to this cable and walk around. Of course this limits the range of the astronaut to within a few meters of the cable. And you'd need a small asteroid to avoid having to bring gigantic spools of cable.
NASA is exploring this idea too, putting a grid across the asteroid:

This area of study is still young, we've never landed on a small asteroid yet so there are many questions regarding how solid the surface is etc.

It might be preferably to be walking on asteroid than on Mars, given the length of the zero-gee time on the journey (if that's how they end up doing it). Hopefully the ISS experiments on avoiding muscle loss will have reached full fruition before then.

I imagine that either walking poles, perhaps with retractable "barbs" of some sort, or equivalent footwear that has a temporary, reversible surface fixing action, would allow a reasonably cautious walker to make good time across the surface of an asteroid. And, yes, either safety lines or something like SAFER (link).

Any activity that involves pushing down or into the surface - drilling, for example - would need extra caution.

• I suppose you're thinking of a near Earth asteroid, right? Because going to the asteroid belt will take much longer than going to Mars (trip to Mars is about 20 megaseconds one way (~220 days), trip to the asteroid belt is over 100 I believe, so at least five times longer.). Sep 10, 2018 at 10:55
• I'm pretty sure that was the basis of the original "astronaut visiting asteroid" plans. I haven't heard anything recently about such plans though, so they may now be sitting on a shelf. Sep 10, 2018 at 17:37