Strong man in the moon?

June 18, 2009 9:44 AM

With the advent of NASA's return to the moon I have a question of whether or not The Apollo astronauts could have recovered from a less than perfect landing.

The new Lunar Reconnaissance Orbiter (LRO) can map the moons surface with much greater detail than in the time of the Apollo landings. During the descent of the Apollo 11 Lunar lander Niel Armstrong had to fly over an unexpected boulder field. Assuming he didn't, and landed the LEM, and it tipped over, could the two astronauts tip it back up so that it could launch again?

posted by Gungho to science & nature (19 comments total)

The lunar module weighed 10,000 kg. On the moon's surface it would still weigh over 7,000 pounds. There's no way two men could right something weighing more than an H2 while wearing space suits.
posted by 0xFCAF at 9:51 AM on June 18

But I bet NASA's top men would have concoted some sort of incredibly sophisticated system (erm, or maybe just a lever?) to put it back upright. I think the more pressing question is whether or not the lander would have been damaged too much to take off again.
posted by Grither at 9:54 AM on June 18

They did have a jeep... and some cables... and a whole lot of engineers back home with slide rules and advanced lever knowledge... but it still seems like quite the challenge.

Heck of a story there, though (lurker: give me a thanks in the introduction, please and thanks. Upper R.)
posted by rokusan at 9:55 AM on June 18

It was a pretty fragile piece of machinery. I don’t think the ascent module would have survived a tip-over. Not to mention the antennas, directional rockets and whatnot sticking off the side would have also been damaged, which would have made navigation and communication difficult or impossible.

Also, the hatch was just barely big enough for a suited astronaut to exit with some guidance from the other one. I don’t think they’d have been able to get out of the lander if it were on its side.

Assuming they’d even be able to communicate with Earth after it tipped over, I’m sure NASA would have tried tried very hard to get it back. Perhaps they could have detached the ascent module from the descent module and righted it with some pullies. They had a few of those, both on the harnesses that secured the astronauts during landing and in the “Italian clothesline” they used to get the rocks back into the ascent module.

Apollo 15 landed on a bit of a slope:

"A few seconds later, Scott informed the ground that "Okay, Houston. The Falcon is on the Plain at Hadley." Falcon was tilted nearly 10 degrees to its back left, just 5° below the maximum acceptable angle. It set down on the rim of a crater such that its engine bell was damaged, and with one of the legs in the crater."

So if the maximum acceptable angle is 15 degrees, I'm sure anything more than that and they'd still be there.

15 was the first mission to bring along the rover, but I doubt very much it would have helped them much. It was attached to the side of the DM and unfolding it required a pretty complex proceedure which probably wouldn't have worked if it were on its side. Plus, the rover was very light and in the lunar gravity it most likely wouldn't have had enough traction to help pull over the lander.
posted by bondcliff at 10:08 AM on June 18 [1 favorite has favorites]

0xFCAF: The lunar module weighed 10,000 kg. On the moon's surface it would still weigh over 7,000 pounds.

Isn't the calculation (roughly) 10,000 x 2.2 x 1/6 = about 3600, or the approximate weight of a Camry?
posted by Doofus Magoo at 10:10 AM on June 18

Isn't the calculation (roughly) 10,000 x 2.2 x 1/6 = about 3600, or the approximate weight of a Camry?

Yea, you're right. I was thinking of Mars' gravity, not the moon's.
posted by 0xFCAF at 10:13 AM on June 18

The more I think about this the more I think, if they didn't die right away, they'd be stuck.

Here's a diagram of the LM. Those fuel tanks on the side would surely be ruptured if the thing tipped over, as would all the reaction control thrusters and antennas.

I believe they did have a contingency for collapsed landing struts and hard landings, which was probably just like an abort before touchdown. As long as the ascent module wasn't damaged they'd probably have been ok. But if the whole thing tipped over? No f'n way they'd be coming home.

If you ever have a chance to see the Imax film Magnificent Desolation go see it. They showed one scenario of how they'd return to the LM if the rover crashed and one of the astronauts had a damaged space suit. It really is an amazing film.
posted by bondcliff at 10:25 AM on June 18

They did have a jeep

Only for the last two missions. And it was kinda fragile, more golf cart than jeep.
posted by Rash at 10:26 AM on June 18

The "Apollo Lunar Module Landing Strategy," (PDF) outlines the abort option ("Abort after Touchdown," p. 205). They could abort up to an angle of 40 degrees, if I'm reading it correctly. There's a good diagram on p. 239. Of course, the pilot had about 1.4 seconds to perform the abort and switch to ascent mode.
posted by steef at 10:30 AM on June 18 [1 favorite has favorites]

Only for the last two missions.

Last three missions actually.
posted by Brandon Blatcher at 10:34 AM on June 18

To take this one step further, I have often wondered what it would have been like for Michael Collins, the command module pilot, to leave his stranded colleagues behind and return to Earth.

Assuming that the LEM was irreparably damaged, Armstrong and Aldrin would have been left with a finite life span, measured by the amount of oxygen they had. At some point, Collins, still orbiting the Moon in the command module, would have had to leave. I assume he would have stayed with them until the end, but it's a little unsettling to put yourself in his place, returning to Earth with two empty seats beside you.
posted by dinger at 10:42 AM on June 18

They could abort up to an angle of 40 degrees, if I'm reading it correctly.

Actually, I think it is saying that it won't tip over unless it's over 40 degrees. Which is really much steeper than you might think. Like, one leg on a 10' boulder and the other one on the ground.
posted by smackfu at 10:42 AM on June 18

Speaking of Michael Collins- Jethro Tull's "For Michael Collins, Jeffery, and me"

I'm with you L.E.M.
though it's a shame that it had to be you.
The mother ship is just a blip
from your trip made for two.
I'm with you boys, so please employ just a little extra care.
It's on my mind I'm left behind
when I should have been there.
Walking with you.
posted by Gungho at 11:14 AM on June 18

I assume he would have stayed with them until the end, but it's a little unsettling to put yourself in his place, returning to Earth with two empty seats beside you.

Initially I would have assumed that this is part of the training: the possibility that the command module pilot is coming home all by himself. After all, William Safire famously had written an address for Nixon to give in the event Armstrong and Aldrin could not return (although, of course, this did not become common knowledge until decades later). Then I recalled that Apollo 13, after being unable to land on the moon, had a problem with its return plan because NASA had failed to account for the command module having several hundred kilos less mass than planned (no moon rocks). If they were failing to account for a shortage of cargo, I dunno that they would plan for a shortage of crew. I now wonder if two missions earlier they had thought to make contingency plans for being two astronauts short on the trip home.

In any event, its odd to put yourself in Michael Collins' place anyway: once Armstrong and Aldrin had gone to the surface, and Collins was orbiting the far side of the moon, he was more alone than any human in history had been: totally cut off from any other human, and unable to even see Earth.
posted by ricochet biscuit at 11:27 AM on June 18 [3 favorites has favorites]

Collins touched on that in his book, Carrying the Fire. He was trained for it, though he knew if he actually returned without Armstrong and Aldrin he'd have been a marked man for the rest of his life.
posted by bondcliff at 11:40 AM on June 18 [2 favorites has favorites]

With little to do with this actual issue, let's all just pause and remember just how fine those men performed and how much they inspired us all and be glad Armstrong took over the landing and flew those last few hundred meters to a safe landing with next to zero fuel left and a steely cool talent. He had seconds to spare as he brought the craft to a landing attitude and was in fact within seconds of an abort. Thank you Professor Armstrong heroes are rare these days.

About 30 minutes into this audio:

http://www.honeysucklecreek.net/msfn_missions/Apollo_11_mission/apollo11_audio.html

Still chilling, isn't it?
posted by Freedomboy at 12:16 PM on June 18 [1 favorite has favorites]

To get back on topic... The LEM was built for landing, not for rolling over. With every ounce removed to save weight there was essentially no internal bracing--just enough to keep it together during the launches. And even then it did occasionally permanently deform from the power of the lunar launch crushing it a bit. Most of the skin was roughly as thick as a tin can and astronauts speak of some concern that they could punch or kick through the hull. It was made to hold pressure and take a couple G's in the vertical axis, and that's about it. I really doubt if it would remain operational after a tip, especially a violent tip that would come from landing. At very least it would crush two pairs of maneuvering jets. Also communication with clever people on earth would be a big problem unless they could get the surface antenna deployed, which would depend on which side it fell.

Even if it did survive operationally (though it wouldn't need to be air tight, but a lot of systems would still need to work) there's no good leverage point near the top of the LEM that could take the kind of leverage that 2 astronauts with only small geology tools could apply to tip a 3,600 pound machine without damaging it more. They don't have tow hitches on the thing. Pulling on the EVA antenna mount is just going to get you a broken antenna.

Looking a the measurements, if they tipped with the forward hatch down I don't think that a suited and backpacked astronaut could get through the top hatch. (Though they could with hoses attached to internal systems like Apolo15's Stand-up EVA, but the hoses were only about 8 feet long and wouldn't do them much good outside.)

Also if they fell over because they landed on a giant rock or on the edge of a crater then they'd need to carry/slide the rover to a flat location. I don't believe even a well motivated pair of astronauts would have that power. They were generally bone tired doing geology in their suits for 6 hours. There are charts with estimated calorie burn rates for EVA's, they're often really high, even for fit astronauts driving rovers and whatnot. Stuff takes forever on the moon. Even duct taping that fender back on the rover took something like 45 minutes.

On the other hand they had lots of tools, possibly cables for the ALSEP deployment (if they could get to the MESA), the resources of the bottom part of the lander which they only need as a launch platform, and a few missions had a couple dozen small explosive charges for geology experiments. So a dedicated science fiction author could maybe make somethign exciting from all that.
posted by Ookseer at 12:40 PM on June 18

This is all very appropriate with the 40th anniversary of the first moon landing on July 20th.
posted by Flying Saucer at 12:54 PM on June 18

Obviously less than perfect is one thing, but a tipover is pretty much endgame.

I really question whether a tipover at anything but the very very end of the landing sequence would even be survivable. You'd have an emergency situation that would make Apollo 13 look like a cakewalk even if it did.

The rover was just 200kg, so obviously there's no possible way it could pull the LEM upright. I suppose if you want to get creative, like the kids who came up with ways to save the Titanic, you could imagine rigging some sort of combination of levers and nylon lines and such, but I really think it's unlikely -- and it depends on the assumption that the landing was survivable, which again I think is a very big assumption.

Really, there were a lot of ways they could have gotten stuck on the Moon even without a disastrous landing, so we don't need to make any ways up.
posted by dhartung at 9:04 PM on June 18