The United States apparently left several of the lunar rovers on the Moon at the end of their mission (hey, less weight when taking off!).
Are the lunar rovers still operable in the sense that we could land a ship next year, walk over to the rover, and power it up and use it as a viable means of transportation? Assume for the sake of this question that you are allowed to swap in a new battery, charge the battery, or add fuel or possibly do minor regular maintenance tasks, but no overhauls, rebuilds, or extensive repairs.
Do the lunar rovers have keys? “Hey Captain, what did you do with the lunar rover key that NASA gave us? It won’t fire up without it.” “Uhh, did you check behind the box of Tang?” “Oh, thanks, here it is. Forget my O2 next.”
Are they likely to be in good driving condition after all these years? I’m guessing that as long as they are intact (not hit by meteors, not sabotaged), the answer is yes, because the lack of an appreciable atmosphere and the lack of life is going to greatly slow down wear and tear (i.e. no rust, no wind, hail, or storm damage). One thing I might be concerned about would be the temperature extremes - would that damage it?
Please, no conspiracy theories in this thread, please.
They definitely don’t have keys. (There would be no point. And you don’t add pointless hardware on a space mission.)
The LRVs were entirely electric. I’m sure with modern battery technology they could operate for a lot longer than the original batteries allowed.
All three rovers that were used (Apollos 15, 16, and 17) performed well and were still in working condition when their LEMs departed the surface. We do know the locations where they were left. Whether they’ve held up to 40 years of unprotected solar radiation and micro-meteor strikes is anyone’s guess.
Temperature, micrometeorites, and radiation will have degraded the LRV to the point that the vehicle is non operational.
No key, just turn on the switch and move the control handle (each wheel had its own electric motor).
Batteries are primarys (non-rechargeable silver-zinc potassium hydroxide), but even they were rechargeable, they’d never survive the lunar night; lows can reach -300°F without heaters.
Any on-board electronics would probably so damaged from the cumulative radiation exposure (the Sun, cosmic rays, etc.) that all they would do is serve as resistive heaters for the battery.
Exposed polymers would be as fragile as a spider web; outgassing and the fore mentioned temperature/radiation/micrometeorites will weakened the material so much that merely touching thinner sheets would cause it to disintegrate or shred. The back of the seats used Nylon webbing; they’d pretty much be dust now. Covered materials, OTOH, are only subject to outgassing, aging, and attenuated radiation. My guess that the polymer of choice back then (and still is today) is fluropolymers; I believe they’ve been used since the 60’s (witness the 70’s Voyager I and II are still operational), so they would remain pretty robust even now.
So you need a new set of batteries, electronics, and some webbing. Sorry, robert_columbia not only are parts are hard to get, but a fix requires a tow back to my shop. And my prices are out of this world–cash up front, please.
Another possible problem. I don’t know if the rovers had the same problem, but I recall reading that the old Mercury capsules kept in museums degrade themselves over time because they are made of metals that are chemically incompatible and corrode each other on contact. They were designed for maximum performance and minimum weight, but weren’t intended for long term use so no one cared if the materials would eventually start eating into each other.
The vacuum of space is real hard on lubricants. The original mission requirement was to have the Rover last for about 2 weeks from launch to abandonment. It’s 42-ish years since then. In other words, we’re about 1000x beyond the design lifetime of the machine. To be sure they haven’t had any use since then, but they have been sitting outside in a very harsh environment.
I’m gonna bet that any moving parts which had lube then don’t have lube now.
The Lunar Roving Vehicle (LRV) is 'Sixties-era technology (deployed in the early 'Seventies, but designed several years previous). The “electronics” are pretty minimal and doubtless consist of discrete surface mount GaAs semiconductor devices which are fairly robust against incidential radiation.
Chemical corrosion requires a medium, e.g. water or some other fluid to carry the ions. Although surface corrosion and “vacuum welding” can occur outside of an atmosphere and other types of breakdown can occur due to ionizing radiation, chemical corrosion is very limited.
Actually, although nylon is fairly stable in dry, controlled storage, it breaks down fairly rapidly with continuopus exposure to both sunlight and salt water, which is why it is no longer favored for marine applications such as sails, although it is fine for applications like parachutes that will see intermittant exposure.
The real thing that will stop the LRVs from being useful is the most pernecious contaminant on the surface of the Moon; the ionized fine Lunar dust that gets into everything, electrostatically attaches itself, and then rapidly becomes a cement that prevents moving parts from functioning. There are numerous studies on the effects of Lunar dust that explore the issues and mitigations with respect to long term operation on the Lunar surface, and all conclude that it would present one of the major stumbling blocks to long term or continuous operation on the Moon’s surface.
Doesn’t matter much; if the surfaces of incompatible metals corrode each other to the point they break from each other that should be more than enough to wreck that part of the machine.
Made the mistake of buying a Nylon car cover in the spring of one year; by winter when the first serious winds blew, I watched faded blue patches and threads blowing across the field into time immemorial.
Hmm…blame my bias using exclusively rad-hard Si for mostly digital applications; I wasn’t aware GaAs was available in the 60’s-- but were the discrete components custom made or commercial/military components screened/upgraded for use in space?
You still need a medium to complete the circuit. Localized “solid state” corrosion is limited because the migration paths for ions are limited and are disrupted by the act of corrosion. What usually occurs with dissimilar metals in contact isn’t that they lose structural integrity at the interface, but that they either electrolytically “weld” together (bad for moving parts) or due to the difference in electronegativity creating a charge differential, resulting in oxidation of the lower electronegative material. This requires oxygen or some other oxidizing element to participate in the reaction
Yes, hardware used for space applications is hardened against the incased high energy radiation environment, and also designed to withstand the greater damage and dysfunction. However, they weren’t designed to operate for decades of continuous exposure.
Is there any reason to expect the dust environment to be similar, or different, on any other rocky body lacking an atmosphere? Would exploring Phobos or Ceres or … be expected to have the same issue to the same degree?
Superficially all rocky bodies appear similarly cratered & of similar age. My layman’s guess is that in the absence of liquid & atmosphere, the “weathering” to micro-dust is a one-way process driven mostly by the passage of time.
Perhaps the intensity of solar flux is a driver, in which case we’d expect less dust, or coarser dust, the farther out from the Sun we are. OTOH, if enough time has passed and the dust acts as an insulator protecting the rocky surface beneath, then perhaps even deep space bodies have already dusted themselves up to an equilibrium state.
I have heard that they were designed to be re-used with a swap out of the battery pack, but this, even if true, would be by a lunar mission closely following the Apollo landings. I don’t think it would be any more of a study and curiosity to see if they still worked today.
