Any Possibility of Landing on Mercury?

Factual Questions
1

Inspired by the Mars and Venus threads

Would it even be feasible to land a manned mission on Mercury or would this be like Venus and too difficult to obtain ?

Of note there has only been 2 probes to Mercury and the last one Messenger, just crashed there recently.

I suspect the heat and the location of Mercury being close to the Sun would make this difficult (and expensive) but would it be feasible?

Thanks for any responses

2

http://boards.straightdope.com/sdmb/showthread.php?t=739078&highlight=mercury

Searching old threads I do see some discussion on Mercury here

3

Mercury has three key advantages over Venus: It’s got a lower mass, it doesn’t have any atmosphere, and it can get pretty cold at night. Weighing against that is the fact that it’s closer to the Sun, and thus harder to get there to begin with, but that can be worked around, especially if you’re patient enough and/or willing to burn enough fuel.

4

Something else that I just thought of.

What about returning to Earth ?

It is already tough enough to get there with the gravity of the Sun. Would it be just as hard to return to Earth ?

At least we would not have to deal with the heavy Venus atmosphere for liftoff

Thanks for any responses

5

I can tell you that in Kerbal, Mojo is probably the most difficult of the planets to get too. Many a fine Kerbal has lost his life in my quest to land on and return from that cursed planet!

We’ve sent mapping probes to Mercury, so landing shouldn’t be TOO much of a challenge, and I seem to recall that one of the space faring nations is or was planning to make an attempt at some point.

6

Mercury is so deep in the Sun’s gravity well that matching orbits with it requires a lot of velocity change. The Messenger probe was only able to do it because it used multiple flybys of Earth, Venus and Mercury to gain gravity boosts, a process that took years- far too long for any manned mission. At a minimum a manned mission would need high efficiency electric or solar sail propulsion. Next, without any atmosphere a landing would be 100% dependent on rockets. Daytime temperatures would be extremely difficult to cope with, and a solar flare would probably be lethal. Not impossible- with enough payload you could do almost anything; but probably several times as difficult as a Mars mission.

7

That’s the trip there - a return to Earth would be even more difficult.

8

Sorry…I thought we were talking about unmanned probes. I doubt a manned mission would be possible.

9

Unlike the old joke about a mission to the Sun, here “send it at night” really is an option. You’d need some non-solar power source (probably an RTG), but that’s not too hard, and we use those on missions to the outer system all the time.

10

Sorry,
I should have put it in the title that it was a manned mission

It seems to me that in order of difficulty for manned missions

1, Moon
2. Mars or a moon of Mars
3. Ceres
4, Other Asteroids
5, Jupiter Moons
6. Saturn Moons
7. Mercury
8. Uranus Moons
9. Neptune Moons
10 Venus
11, Pluto

There would be change in the later orders depending on one’s opinion I think but the only ones that are realistic possibility are the first 4 on a technical basis, not including any political issues.

Thanks for any future replies

I really enjoy learning from this

11

That’s not an advantage. The inability to use aerobraking or aerocapture is a substantial loss.

True, the atmosphere on Venus’ surface is so thick that taking off again would be a substantial challenge. Balloons would certainly help. A very sleek rocket might be good enough, though.

Here’s a delta-V map of the solar system. You need 9.4+2.44+0.68+0.09+0.28=12.89 km/s just to get moving toward the inner planets. From there, you need 2.06+6.31+1.22+3.06=12.65 km/s to land on Mercury, and 3.06+1.22+6.31=10.59 km/s to take off again and get moving toward Earth. You can aerobrake the rest of the way. That’s a total of 36.13 km/s.

Landing on Venus doesn’t require any delta V past the original 12.89 km/s. The chart shows 27 km/s to LVO, but that’s with some very pessimistic aerodynamic assumptions. LVO is around 8 km/s, like Earth, so with balloons or the like, 10 km/s should be achievable. Add to that another 2.94+0.36=3.3 km/s for the transfer and you get a total of 26.19 km/s; much better than Mercury, even with the much larger mass.

Obviously, just surviving on Venus’s surface is a difficult problem. So overall, Mercury probably wins. But that’s more a result of its particular circumstances rather than it having any atmosphere at all.