Could we land a human on a asteroid?

[Sylandro]

Well, we landed on the moon, right?

So we're sure we can land a man on an asteroid, and one of my most positive guesses on a potential landing site is the NEO Apophis. ( http://en.wikipedia.org/wiki/99942_Apophis )

But of course, we would have to calculate it's closest encounter and other math and science calculations that i don't under stand yet.

So yeah, ts;cr, we could land on a asteroid with the correct calculations.

Sylandro's orbit box

Apophis

http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=Apophis;orb=1;cov=0;log=0;cad=0#orb

[lajoswinkler]

I doubt we could land a human or anything. We might try to attach them, tough.

[Sylandro]

I doubt we could land a human or anything. We might try to attach them, tough.

That if, we can send a mapping satellite into orbit around the asteroid and check for potential landing sites.

[Moon Goddess]

Sure, but the question is what are we landing on? A lot of asteroids are no more solid than a pile of gravel. Every walk up a pile of gravel? now imagine landing on that with rockets...

[Ralathon]

Who said anything about landing? It's an asteroid. To get down from orbit you simply jump from your ship in a retrograde direction and fall down the last kilometer or so. Maybe take a scuba tank with you for some extra dV to pinpoint your landing.

Anyway, the rocket exhaust in a vacuum expands really quickly. If you remember footage of Apollo landings they only started to kick up dust a dozen or so meters above the surface. Due to the minimal gravity on an asteroid this would be even less(Less thrust = quicker exhaust dispersion). Landing on an asteroid is really really easy. They actually did it with a probe that wasn't even designed to land (NEAR Shoemaker).

[lajoswinkler]

Pile of gravel with barely any observable gravity. For most asteroids, an astronaut pushing himself against the surface with his finger would send him into a large orbit. The act of jumping would make you reach escape velocity.

Gilly-sized object in real life would be impossible to land on in a reasonable time. You could only rendezvous with it and then attach yourself to it. If you fell on it, your internal body/suit springiness would probably launch you in another (sub)orbital trajectory. Imagine few hours of bouncing like a dumbass, trying to get hold of gravel.

EVA on the surface of an asteroid might be quite dangerous, as one could dislodge the material, opening paths to underground pits. Not that one couldn't climb out, but imagine getting stucked between the boulders while the regolith slowly pours down on you.

Edited September 25, 2013 by lajoswinkler

[Dkmdlb]

If you fell on it, your internal body/suit springiness would probably launch you in another (sub)orbital trajectory. Imagine few hours of bouncing like a dumbass, trying to get hold of gravel.

I see a new Adam Sandler movie on the horizon...

[Technical Ben]

We should land an asteroid on a human...

[Sylandro]

But then, it'd cause the apocalypse, man!

[Pds314]

So, imagine that we use a few tonnes of fuel and throw Apophis into and eccentric orbit of Earth where we can study it and land on it and mine the 27 megatonnes of iron and >1 megaton of volatiles and do whatever else we want with it.

It is perhaps 320 meters across and has a mass of around 40 Megatonnes, these factors yield an average surface gravity of around 100 microns/sec^2, or about 1/100,000th of a G.

They yield an escape velocity of around 187 mm/s, which is low enough that the asteroid would have to rotate at most once every 2 hours or so to avoid throwing anyone on it off into space.

Additionally, if it were close to earth at all, let's say, at Geosynchronous orbit, Earth's own gravity would be of significance.

In fact, being 160 meters closer to Earth than the core of the asteroid or 160 meters further away could cause you to go flying out into space even more easily.

You'd experience 16 microns per second squared less gravity when earth is at noon or midnight.

You'd be moving about 1/300000th of your velocity slower or faster as well.

Your velocity would be around 100 millimeters per second less/more than that required to orbit Earth circularly.

This would result in an extra 1.5 microns per second squared less felt gravity.

But here is the catch.

Even though the likely g-force on you are still around 81.8-100 Microns/second^2, (remember that the asteroid would probably rotate once every 24 hours as to track the earth, therefore its centripetal acceleration would be important)

You won't be able to walk very well if Earth is at midnight or noon due to the Hill sphere of Apophis being so small at that range, you wouldn't have to reach escape velocity to never fall back down, drifting off into space would be very easy.

You'd only have to jump like 240 meters high to reach L1 at noon.

The problem with that is that it takes only takes like 100 mm/s to send you to that height, and you'd be floating around for 20 minutes or more on your way there.

However: this does not necessarily mean that a landing would be impossible, though it would be very different from a moon-landing, and would need more safety equipment, the simplest solution would probably be gecko-like hairs on the boots of astronauts, the landing legs of the lander, and the wheels of any rovers.

It is also worth noting that such a solution only works if there is little-or-no dust in the area, rendering useless for larger rubble-pile objects.

Additionally, they should probably take a note from KSP and give EVERYTHING RCS/Jetpacks, just in case.

If jetpacks aren't practical, then there is still the possibility of giving everyone a grapple with some double-stick gecko-hair pad tape on the end, or two, as per the game double wires.

[Tex]

In my experience, a manned asteroid mission is completely feasible. We have landed probes on asteroids before (Deep Impact), after all! Many theories range about going and mining asteroids for precious metals, so I don't see why asteroid landings aren't an eventuality.

[DerekL1963]

In my experience, a manned asteroid mission is completely feasible.

And what *exactly* is your experience?

We have landed probes on asteroids before (Deep Impact), after all!

Um, I hate to break this to you... but Deep Impact *crashed* (by design). Landing is a much different and much harder problem.

[WestAir]

Of course we can land a human on an asteroid. With a lot of planning, technology, and most importantly fuel and air.

The real question is: Can we land an asteroid on a human? There's your true test of skill and cunning.

[OtherDalfite]

Um, I hate to break this to you... but Deep Impact *crashed* (by design). Landing is a much different and much harder problem.

While it did crash, it was a controlled one. Landing is basically crashing in slow motion, so I don't see why we could land on one. The only hurdle I can imagine is if we landed on a hillside, and even then, I can see the situation being recoverable.

[nuclearpower13]

Well what do you mean by landing? For example eros has a gravitional pull of 0.0059 m/s. You could "stand" on eros as long as your not pushing down and your remaining as still as possible but you would need a jet oack or anchor to stay connected to the surface. But also entering orbit around an asteroid is also questionable. It would be more of a rendezvous with the asteriod rather lowering your deta v enough to enter a relativly circular orbit around the object. Getting an orbit around Ceres and Vesta is possible but as far as i know not possible with any other known belt object.

[lajoswinkler]

It's worth noting that landing on elongated asteroids would be quite a problem. Not only you'd have to approach at such direction to avoid it slam into you by its rotation - you'd have a weird gravity field around it, and it's already weak so... expect the unexpected.

[Mr Shifty]

Um, I hate to break this to you... but Deep Impact *crashed* (by design). Landing is a much different and much harder problem.

- NASA's NEAR Shoemaker probe landed on 433 Eros in 2001 and continued to scan the asteroid and send data back for several days after landing.

- Japan's Hayabusa probe landed on 25143 Itokawa in 2005, and returned a sample from the asteroid to the Earth in 2010.

[nuclearpower13]

@Mr Shifty

Did Shoemaker and Hayabusa use anchors to stay connected to the astroid?

[cypher_00]

No neither of them used an anchor.

[Mr Shifty]

@Mr Shifty

Did Shoemaker and Hayabusa use anchors to stay connected to the asteroid?

No anchors. Eros is the second largest NEA: 34kmx11kmx11km. Gravity at its surface is 0.0059 m/s² So the 478kg spacecraft had a surface weight of about 2.9N (0.7 lbf), which apparently was enough to hold it to the surface even with the relatively high landing speed (~1.5 m/s). The probe orbited the asteroid for about a year prior to descent; orbital speed was something like 10 m/s.

Itokawa is a much smaller asteroid: 530mx200mx300m. Hayabusa basically did a touchdown and re-launch. It made two touchdown attempts and only got samples because the descent kicked up some dust into the sample collection funnel. (The sample collection projectiles failed to fire on both touchdown attempts.) It also released a mini-lander called MINERVA which was supposed to hop across the surface of the asteroid, but due to an autonomous response by Hayabusa during the time-lag from when the probe release command was sent from mission control on Earth, it released at the wrong altitude, escaped Itokawa's gravity and is now circling Sol. I don't believe Hayabusa orbited Itokawa; I think it just maintained station like a spacecraft waiting to dock with the ISS.

[dharak1]

That makes one side longer than Eve's moon! Cool, really puts the KSP universe into perspective!