Here’s The Minimum It Would Take To Get The Lunar Rovers Running Again When We Get Back To The Moon

As we speak, there are four daring astronauts that have just flung around the moon for the first time in over 50 years, and are currently, let’s see, as of this writing, about 136,700 miles from home. This particular Artemis II mission is going to (hopefully) be the start of many more missions to the moon, including ones that will put people back on the surface of the moon, and, ideally, establish some manner of permanent presence on our only natural satellite. This is exciting to me. It also means that, if we’re going to be going back to the moon, we’re going to need some way to get around.

Sure, there will be new, advanced lunar roving vehicles developed, I have no doubt, but this is the Autopian: we can’t just ignore the fact that there are at least three perfectly good used car projects just waiting for us on the moon! They all ran when parked, too, and I’m pretty sure rust or mold isn’t a problem up there on the moon, so I think what we’re looking at here are three smoking-hot deals, just waiting to be had!

You’re all familiar with the Lunar Roving Vehicle, right? They’re all 1971 and 1972 models, and there was a production run of three, not counting earthbound test versions, all bound for export to the lunar market. These rovers went up on Apollos 15, 16, and 17. Here’s some nice video of one of these babies in action:

They all should be in about the same general condition, though the Apollo 17 one had a minor mishap that led to it having one of its fenders repaired with some tape and lunar maps, so if you want a minty one, go for the 15 or 16 ones:

A Little Overview

They did their jobs incredibly well; NASA wasn’t going to take any chances, so they made a rule that the furthest astronauts could drive the rovers would be in a circle with a six mile radius, the maximum walk back an astronaut could do given the restrictions of supplies in their spacesuits. Even so, that gave a lot of area that could be explored, far more than could be done on foot, and on Apollo 17, for example, they drove 22 miles in the rover. This was well within the 57 mile range of the rover’s batteries, which we’ll get into more detail about soon.

The rovers had a total of only about one horsepower, divided between four 1/4 hp motors, one driving each wheel. That may not seem like much, but you have to remember that the moon only has 1/6 of our usual gravity, so even though it weighed about 480 pounds on Earth, on the moon that’s under 80 pounds! It was rated with a top speed of 8mph, but Gene Cernan got one up to 11mph during Apollo 17.

Where To Find Them

Here’s the locations of the three rovers: one at Hadley Rille, one in the Descartes Highlands, and one in the Taurus-Littrow Valley, so now you know what sections on Lunar Craigslist to check.

What Will They Need To Get Going Again?

The good news here is that all of these rovers are very low-mileage, one-owner examples. All were in perfect running condition when parked over 50 years ago. There’s no weather on the moon as such, so really the only wear they likely have been subjected to are thermal fluctuations and the UV rays from the sun, which likely has faded paint and decals and could have degraded some exposed wire insulation, possibly. I’d bring some electrical tape just to be safe.

The biggest thing that will need replacing are the batteries. These were never designed to be recharged. The rovers use a pair of 36V silver-zinc batteries in special plexiglass housings. These batteries were good for 115 amp-hours, or about 4.14 kWh. Either battery could operate the entire rover for redundancy’s sake, though in normal operation one battery drove the front wheel motors, and the other drove the rear.

The batteries are mounted at the front of the rover:

The batteries are under thermal blankets and are also used as heat sinks for some of the other electronics on the rover to help maintain their operating temperatures. Here’s the temperature range NASA set for the batteries:

So, it looks like the thermal system was designed to keep the batteries at an operating temperature between 40°F and 125°F, with a survivable range of -15°F to 140°F. This is actually good news for the plan to restart these rovers, which will involve replacing these batteries with modern lithium-ion batteries, which are generally able to operate between -4°F and 140°F.

Also good news is that there’s plenty of lithium-ion golf cart batteries that are 36V! Here’s a bunch on Amazon! But let’s get  good ones, since we’re going all the way to the moon. This one is a 36V (technically 38.4V, like all the 36V batteries here, but that should be fine) that makes 120 amp-hours/4.32 kWh, so that’s even better than the originals. And I think it should fit pretty well – it’s not exactly the right size, but it’s within a couple inches on each dimension, so I bet with a little hammering/finagling, we can get it to fit. So order two of those.

The procedure for removing/replacing the battery doesn’t seem too bad, either; these instructions are for the Earth-based training rover, but it should be pretty similar to the ones on the moon, because the whole point of this thing was to train astronauts for the real thing:

I think the trickiest bit will likely be the connector; I haven’t been able to find definitively what the battery electronic connectors that were used, but I strongly suspect that it’s a MIL-DTL-5015 connector, likely a four-pin one, based on schematic diagrams. Two pins are for the usual positive and negative terminals of the battery, and I think the other two are instrumentation.

I’d say go up ready for any possibility; have a cable with these MIL-DTL-5015 connectors, but also maybe have pigtails that you can just splice into whatever the rover actually has. I think if you can get the + and – connected, you should be good to go!

How To Drive It

Okay, I’m confident that this is going to work, that the new lithium ion batteries will be able to be crammed into those battery trays, that the thermal management components can be replaced, and  connectors either plugged in or spliced on, and you’ve got 36 rich, creamy volts flowing through the system.

So now what? How can you drive these? Happily, it seems pretty straightforward. First, have a seat in one of the two seats, and look in front of you. You should see the instrument panel:

Hopefully those four vertical lights on the left side will be illuminated, two BUS lights per battery, showing you that you have power. To turn the thing on, you’ll want. to flip these switches to ON:

The leftmost two starts the steering systems (front and rear), and then to the right of that are four switches, one for each wheel’s drive motor, and then four DRIVE ENABLE switches, again one per wheel. So just flick all those on!

Now, to actually drive, there’s a big T-shaped handle in the middle, between the seats. To accelerate, push forward, to brake pull back. If you keep pulling back, you’ll go into reverse, unless that REVERSE INHIBIT switch is on.

To turn, just rotate the handle in the direction you want to turn! It’s that easy!

We Can Do This

There are three perfectly good lightly-used rovers on the moon. It would be criminal to just leave them there! Cars were meant to be driven, after all, and if all these things need are new batteries – which I think it’s a safe bet to assume that’s all they need, it’s at least worth a try – then why not get those classic rides going again?

Think about it, NASA! Why waste the money? These are prime deals, just sitting there!

Story and top graphic images except where noted: NASA