Lunar rover malfunction

[Luke Pemberton]

I've been wondering this for a while now, but what would have happened if the lunar rover broke down, given there was no chance of road side assistance on the lunar surface?

It's clear that the astronauts would have walked back to the LM - before any smart Alec replies with 'they would have had a long walk'   . Was someone back in mission control monitoring their PLSS consumables and advising them they were at their limits of an excursion in the event of needing to execute and emergency LM return? What were the margins of safety with each EVA from the perspective of consumables?

After the PLSS discussions in response to Rene, I'm fairly sure that they would have coped with the extra heat.

I was going to be deliberately dumb and ask what if they got a flat, but thought better of it  I know people here would spot the joke, but I don't want to open myself up to the CTs. The thought did make me chuckle though. I mean, the answer is obvious, they would never have been able to change a wheel in the dark and in the rain. 

[onebigmonkey]

Gene Cernan (in yet another interview with him I watched today!) said that they planned the LRV EVAs so that they visited the furthest point first, that way they were always heading for home if anything went wrong.

[Luke Pemberton]

Gene Cernan (in yet another interview with him I watched today!) said that they planned the LRV EVAs so that they visited the furthest point first, that way they were always heading for home if anything went wrong.

Of course, that makes sense. Feeling stupid here. 

Mind you, I wouldn't fancy the walk if things went wrong at the furthest point, but I can see how visting the furthest point first mitigates the risk.

[Dalhousie]

I've been wondering this for a while now, but what would have happened if the lunar rover broke down, given there was no chance of road side assistance on the lunar surface?

It's clear that the astronauts would have walked back to the LM - before any smart Alec replies with 'they would have had a long walk'   . Was someone back in mission control monitoring their PLSS consumables and advising them they were at their limits of an excursion in the event of needing to execute and emergency LM return? What were the margins of safety with each EVA from the perspective of consumables?

After the PLSS discussions in response to Rene, I'm fairly sure that they would have coped with the extra heat.

There was a concept called walk back distance that the LRV was not supposed to exceed, this was just under 10 km from the LM.  However, as you say the actual distance varied according to consumable consumption, and was constantly re-calculated during the mission.

It's mentioned on both astronautix http://www.astronautix.com/craft/apololrv.htm and wikipedia http://en.wikipedia.org/wiki/Lunar_Roving_Vehicle - doubtless there are people here who can give a primary source.

of course the walk back distance assumes tha tthe LRV is immobilised but there are no other issues.  Astronauts injured after a crash or with damaged suits would be in real trouble.

[Luke Pemberton]

Thanks Dalhousie, that has answered my question. I'm clearly a lazy researcher and should have found that myself, but given the encyclopedic knowledge we have here I opted for lazy. At least I'm honest.

I was rather thinking about the lunar rover malfunctioning rather than astronaut injury or malfunction to PLSS/space suits. I'm imagining the latter would have caused real trouble, even if close to the LM.

[Dalhousie]

Thanks Dalhousie, that has answered my question. I'm clearly a lazy researcher and should have found that myself, but given the encyclopedic knowledge we have here I opted for lazy. At least I'm honest.

I was rather thinking about the lunar rover malfunctioning rather than astronaut injury or malfunction to PLSS/space suits. I'm imagining the latter would have caused real trouble, even if close to the LM.

There was the Tom Hanks IMAX film about Apollo a few years ago that depicted just such an emergency.

My understanding is that there were substantial reserves built into the suits to cope with leaks, and there was also provision for buddy breathing, i.e. one PLSS supporting two people for a short period of time.

[Peter B]

Just to add to the points given above, I understand this was one of the reasons for the long distance walk on the second EVA of Apollo 14 - to test the ability of the astronauts to travel back to the LM - I suspect both in terms of navigation and endurance.

As Dalhousie points out there was a buddy breathing system available, so that if one PLSS failed the astronaut could plug himself into his mate's PLSS and the two would use the water and oxygen. Obviously this would use the consumables faster, but it meant that they'd be able to get back to the LM for an abort...

...except if the rover had failed as well while they were at their walk-back limit, as this limit was based on the two astronauts both having their own supplies.

So in fact if the rover and one PLSS failed while the astronauts were a long way from the LM, then it was a non-survivable situation. Somewhat remarkably, given their insistence on safety margins in so many aspects of Apollo, NASA seems to have accepted this possibility. After all, it strikes me that an accident with the rover (say, a rollover on a hillside) would provide a distinct possibility of damaging a PLSS too.

Incidentally, if you read the ALSJ transcripts for the rover missions, you'll find that walk-back limit is often mentioned as the reason for getting the astronauts to wrap up their investigations of a site and moving on to the next site.

[Allan F]

Thanks Dalhousie, that has answered my question. I'm clearly a lazy researcher and should have found that myself, but given the encyclopedic knowledge we have here I opted for lazy. At least I'm honest.

I was rather thinking about the lunar rover malfunctioning rather than astronaut injury or malfunction to PLSS/space suits. I'm imagining the latter would have caused real trouble, even if close to the LM.

There were multiple options  - first of all they had the OPS - the reserve life-support system which could - depending on which part of the PLSS had failed - could sustain an astronaut for 30 minutes and up. Using both OPS on one astronaut would supply at least one full hour of oxygen and cooling.

On the LRV was a bag, containing hoses to interconnect the two spacesuits, so one PLSS supplied both astronauts.

[Luke Pemberton]

There were multiple options  - first of all they had the OPS - the reserve life-support system which could - depending on which part of the PLSS had failed - could sustain an astronaut for 30 minutes and up. Using both OPS on one astronaut would supply at least one full hour of oxygen and cooling.

On the LRV was a bag, containing hoses to interconnect the two spacesuits, so one PLSS supplied both astronauts.

Thanks, again evidence for the appreciating the reality of Apollo and the sheer volume of knowledge at these boards. These sort of details make me think, how can anyone believe it was filmed in a studio. SG Collins said this about the colour wheel in the cameras, why on Earth would they go to all the trouble of building such contraptions if they faked it?

Thanks for all the replies and taking the time. Again, I have learned a little more and have some key terms to carry out my own research.

Incidentally, if you read the ALSJ transcripts for the rover missions, you'll find that walk-back limit is often mentioned as the reason for getting the astronauts to wrap up their investigations of a site and moving on to the next site.

I will do, thanks.

[ka9q]

Actually, there was no buddy-breathing system between the astronauts.

They did have a hose that would let them share cooling water, but not oxygen.

The idea was that an astronaut with a failed PLSS would first switch to his OPS at a high flow rate to provide cooling as well as breathing oxygen. He would then connect his liquid cooling garment via the buddy hose to his partner's functional PLSS and reduce his OPS flow rate to prolong its lifetime from only 30 minutes to about an hour.

This assumes the LRV is still operational. As has been pointed out, they did not plan for double failures. Had the LRV and a PLSS both failed, they might not have made it back to the LM in time.

But not necessarily. Gene Cernan once explained that had Jack Schmitt's PLSS failed, he would have given him his own OPS, additionally doubling their time margin on the assumption that Cernan's own PLSS would not also fail.