It’s kind of hard not to love the Curiosity rover.

Besides having the coolest entrance to Mars ever, Curiosity also found evidence that the planet could have once supported life. And it sings Happy Birthday to itself every year, which makes us all cry a little on the inside.

When Curiosity reached Mars in 2012, it was only supposed to have a 23-month-long mission. Well, it’s been almost five years, and it’s still going! But every rover has to retire sometime, and Curiosity is starting to show signs of damage.

So how long it’ll last really depends on which system goes out first. Since the mission was only designed to last two years, you’d think the power source would run out first. But Curiosity actually has plenty of power left.

The mission isn’t always in direct sunlight, so it’s powered by a radioisotope thermoelectric generator, or RTG, instead of solar panels. RTGs contain plutonium-238, a kind of plutonium with six fewer neutrons than normal. As the plutonium decays, it generates heat, which makes electricity that charges Curiosity’s batteries.

But plutonium-238 takes decades to break down, which is why NASA has been using RTGs on spacecraft for years. Even the Voyager probes, which were launched with RTGs 40 years ago, still have enough power to communicate with Earth today! So unless we see a new problem with Curiosity’s electronics, the rover will probably still have power for 5-10 more years.

Problem is, Mars isn’t exactly a friendly environment for visiting rovers. The temperature ranges from -125 to 20 degrees Celsius, and Mars’ thin atmosphere doesn’t protect it from most radiation. Mars also has a serious dust problem: there’s clingy, corrosive dust everywhere, and it gets thrown around by violent storms.

Plenty of dust has already collected on Curiosity, but careful engineering has kept the scientific instruments from being damaged. The rover’s instruments are tightly sealed, and the camera lenses are made of thick glass to keep the dust out. Curiosity hasn’t been around long enough to experience one of the planet-wide dust storms on Mars, so there’s a chance that could eventually cause damage.

But for now, the instruments are safe from dust. Debris might actually be a bigger problem. Curiosity’s drill, which it uses to take rock samples, hasn’t been working since December, probably because there’s a piece of debris stuck in the motor.

Engineers are still working to get the drill back online, but Curiosity is continuing its mission in the meantime. Then there’s the radiation issue. Because the Martian atmosphere is so thin, cosmic rays can reach the surface and cause bit flips on the rover’s computer, turning the zeroes in binary code into ones, which can permanently corrupt the computer’s memory.

The hardware on Curiosity is designed to resist radiation, but we couldn’t make it totally foolproof, which is why Curiosity had its first memory failure in 2013. Thankfully, it had a backup computer, so engineers could put the rover into safe mode while they figured things out. And there haven’t been any blue screens of death since!

The primary and backup computers aren’t currently having problems, so as long as radiation doesn’t damage them, they’ll probably last many more years. Right now, it’s looking like Curiosity’s wheels will be the first to go. And it’s not really a rover if it can’t move anywhere, am I right?

After four and a half years, the wheels are full of dents, punctures, and scratches. Some of that is because it’s been a long mission, but it took NASA a while to figure out where the rest of the damage, especially the punctures, came from. The culprit turned out to be a rock called a ventifact.

Ventifacts are pointy, immobile, and stick straight out of the bedrock, and Curiosity drove through areas full of them. Because of the way Curiosity is built, whenever certain wheels get stuck on a ventifact, the other five push the rover harder into the rock. And that added pressure caused punctures.

Since that discovery, the Curiosity team has tried to avoid most ventifacts, because instead of lasting another 30-40 kilometers, the wheels will fall apart after eight if they keep driving over them. So Curiosity should be able to keep doing science for at least a few more years! Now, all this might bring to mind another rover: Curiosity’s predecessor Opportunity, which just celebrated its 13th birthday on Mars!

If you’re wondering how it lasted so long, NASA engineers are kind of asking the same thing. Opportunity doesn’t have computer backups like Curiosity, but somehow all of its parts are still working. Just because Opportunity has lasted so long doesn’t mean Curiosity will, but here’s hoping it does!

And no matter when Curiosity has to retire, it will have lived a long, successful, and science-filled life. Thanks for watching this episode of SciShow Space! If you want to learn more about some of Curiosity’s amazing discoveries, we’ll link to a video in the description about lakes and rivers on ancient Mars.

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