[ ♪ INTRO ] Every rover that successfully lands on Mars is a huge cause for celebration!

But as special as each rover is, with its complex mission and carefully-designed equipment, it’s not as unique as you might think. Sometimes, there’s another one just like it here on Earth.

That rover is built with no intention of leaving our atmosphere, but it has its own important mission: to troubleshoot problems that a rover might encounter on another planet. After all, it would be a real shame if we sent a rover all the way to Mars only for its mission to end prematurely because it fell off a rock and broke. And that’s what twin rovers like Optimism and Maggie are here to prevent.

Twin rovers have been a big part of Mars missions for years. In fact, since the very first Mars rover back in 1997, each one has had an Earthly twin. And today in 2022, NASA’s Perseverance and Curiosity rovers are no exception, with their twins Optimism and Maggie.

These rovers are near-identical copies of their counterparts on Mars. And while their siblings are off on the real Mars doing their thing, these homebodies are roaming around replica Martian terrain at NASA’s Jet Propulsion Laboratory in southern California, USA. And their mission is simple: Help NASA engineers and scientists avoid breaking the rovers they’ve invested so much time, money, and brainpower in getting to the Red Planet.

For instance, in 2020, the Perseverance rover went to Mars to look for microbes while Optimism stayed on Earth to look like Perseverance. Optimism’s name is an acronym for Operational Perseverance Twin for Integration of Mechanisms and Instruments Sent to Mars. Or in other words, “Hi, I’m Perseverance’s Earthbound twin.” Before Perseverance pulls any risky moves out on Mars, Optimism tests them on Earth.

That way, the engineers know exactly what the Mars rover is capable of. They’re not just being optimistic and hoping things work out. Sometimes, rovers like Optimism test hypothetical scenarios.

Like the time NASA researchers were considering what would happen if Perseverance were to drill for microbes from a precarious position on top of a sloped rock. The concern was that if the rover started drilling and then slipped down the rock, the drill could get stuck. Then, we could say goodbye to our dreams of microbe discovery.

So instead of risking it all on Mars, Optimism tried drilling into fake Martian terrain while balancing on a sloped rock. Kind of like you might ask your sibling to see if it’s really possible to jump off the top of the playground before you do it. And Optimism succeeded!

Which gave NASA researchers the confidence to say that Perseverance could do it on Mars if needed. But Optimism isn’t the only twin rover solving problems from Earth. Curiosity’s sibling, Maggie, the Mars Automated Giant Gizmo for Integrated Engineering, has even solved non-hypothetical problems.

In 2011, while Maggie stayed in California, Curiosity went to Mars to collect surface samples and learn about the planet’s ancient climate. And to collect those samples, Curiosity used a retractable drill. Normally, the drill would extend out between stabilizers that kept it on target.

But in 2016, the drill stopped working. One day it just didn’t extend beyond the stabilizers. . The team at the Jet Propulsion Lab was able to work with Maggie to successfully extend the drill, but the only way they could manage that was to go beyond the stabilizers and render them unusable.

So now, engineers had to figure out if Curiosity could get away with drilling without the help of its stabilizers. They designed a system that let Curiosity monitor the drill’s position and re-center it while the robot was still in the middle of drilling. This is something that we do pretty naturally when freehand drilling, but teaching a robot to do it required repurposing the force sensor on the rover’s arm..

This part was originally designed to monitor whether Curiosity was drilling into something so hard that it could break itself. But the engineering team turned it into more of a navigational guide to keep drilling on target. After over a year of troubleshooting, Maggie showed them that this kind of freehand drilling was possible.

And as a result, Curiosity’s first attempt on Mars went exactly as planned. That said, no matter how much planning NASA does, these robot siblings can never be complete mimics. After all, even if they’re driving on perfectly replicated Martian terrain, rovers like Optimism and Maggie are still in California.

That’s why they’re siblings, not clones. For instance, Perseverance’s electronics need to be kept warm through Mars’s freezing temperatures, while Optimism’s electronics need to be cooled in the California desert. And Earth has stronger gravity than Mars, so Optimism needed to be built with thicker wheels to support the rover under all that added pressure.

Sometimes, those modifications are even enough to make a triplet useful. In fact, NASA took that route with the Curiosity mission: Along with Maggie, they built a third rover called Scarecrow. While Maggie had all the brains that Curiosity had for procedural troubleshooting, Scarecrow, like the Wizard of Oz character, did not.

That let NASA do things like test the rover’s ability to make it over a sand dune without jeopardizing an expensive computer in the process. And without a brain weighing it down, this rover could be built with the same wheels as Curiosity and serve as an even closer replica to the rover on Mars. Also, as a bonus, Scarecrow can also inform how Perseverance gets around on Mars, since Perseverance’s body was based on Curiosity’s.

Now, ultimately, these twin rovers can’t solve everything. But twins and triplets are great for troubleshooting the numerous problems that a rover might encounter. From the extreme temperatures to dust storms to broken robot parts, exploring Mars isn’t a walk in the park.

So, you might say these rover siblings are really a testament to how much perseverance it takes to keep them running, and how much engineers are always doing behind the scenes. And to help keep SciShow Space up and running, every month we make a new Pin of the Month. Since June is almost over, there’s only a few more days to order the GALEX pin!

But then we’ll have another space explorer for you to collect in July. You can find them at DFTBA.com/SciShow. Thank you for your support and for watching! [ ♪ OUTRO ]