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This Monday, the population of Mars increased by one with the successful touchdown of NASA’s InSight lander! I don’t know about you, but I cried.

We have less than a 50% success rate at landing operational robots on Mars, so feel free to clap, or cry a bunch, or hug your neighbor like all those hard-working mission control people! Now that it’s landed, InSight will begin its mission to study Mars’s interior. And so far, everything seems to be going really well.

Only a few minutes after we received confirmation of touchdown,. InSight sent back its first photo of the surface. The camera still has its dust cover on, so there are a bunch of dark flecks obscuring the view, but you can make out a couple of rocks and the Martian horizon.

Monday evening, InSight also opened its solar panels, and ever since, it’s been soaking up all that juicy solar energy to charge its batteries. Soon, NASA will direct the lander to start photographing the surface, searching for the best place to position its instruments. It has a sub-surface sensor and a seismometer that will be placed on the ground by a robotic arm.

Once the instruments are put down, they’re stuck there for the remainder of InSight’s two-year mission, so we need to make sure we pick a good spot. It’s actually going to take a couple of months before the lander is fully operational. But when that happens, it‘ll give us the first real look at what’s going on beneath the surface of Mars, both what it’s made of, and how geologically active it is.

So, welcome to Mars, InSight! Now, InSight is only a lander. Mars won’t get its next rover until 2021, with the arrival of NASA’s Mars 2020 mission.

This rover still doesn’t have an official name, but last Monday,. NASA did announce where it’s going to explore: Jezero Crater. It’s a 49 kilometer-wide feature just north of Mars’s equator, and scientists believe it held a deep lake around three and a half billion years ago.

But its exact age isn’t pinned down, so the rover will be working to figure that out. It’ll also study layers in the dirt that show how the lake and its river delta changed over time, and will search for any organic compounds that might have been left behind. Landing Mars 2020 will be trickier than landing InSight.

InSight’s new home is pretty flat, but in Jezero Crater, there are hazards like boulders, cliffs, and possible sand traps that the rover will have to navigate away from during its autopilot descent. But it should be okay. Engineers have gotten better at landings in the last few years, so a successful touchdown is a safer bet than it used to be.

Also, NASA is breaking out new technology for this mission that can take pictures of the ground during descent. If it sees a big enough obstacle, it can activate rockets on the landing system to maneuver the rover away from anything dangerous. Of course, this mission isn’t launching for more than a year, so there will be a lot more information to come.

In the meantime, we can still just be excited about InSight! Earlier this month, while NASA was getting ready to land on Mars, a team of astronomers published even more famous-planet news in The Astrophysical Journal. But instead of it being about our solar system, their paper was about the worlds of TRAPPIST-1.

The TRAPPIST-1 system is about 40 light-years away, and it’s famous because it has seven rocky, Earth-sized planets. With so many options, some people believe at least one of them has to be like our home. But according to this team’s models, these exoplanets might look more like Venus.

Even though the TRAPPIST-1 system made headlines last year, we don’t know a ton about it. We know that its star is one of the coldest types in the universe, an M dwarf, and that at least three of its planets orbit at a distance where liquid water could exist on their surfaces. But we haven’t actually detected any water.

And we won’t know much about these planets’ atmospheres until the. James Webb Space Telescope launches in a few years. So in the meantime, one team has turned to modeling to try to understand what these worlds could look like.

In their new paper, they combined terrestrial climate models with models of photochemistry, or how light from a planet’s star affects molecules. Unlike previous models, they took into account the fact that M dwarf stars are pretty violent when they’re young, emitting a ton of high-energy radiation. And that turned out to be kind of important.

See, that radiation could trigger a runaway greenhouse effect on a watery planet, because it can split molecules of water vapor into hydrogen and oxygen. Hydrogen gas is super light, so it would float off into space. But oxygen would stick around and could react to form greenhouse gases like ozone.

These gases trap heat, so that would lead to more evaporation and more water vapor in the air. Then, that vapor would get broken up, and the cycle would continue. Ultimately, you’d end up with a hot, dry planet a lot like Venus.

The paper talks about other ways this process could happen, too. But either way, the models suggest that most, if not all, of the TRAPPIST-1 planets would have evolved to be hot and dry, with uninhabitable atmospheres. Which isn’t great news for aspiring TRAPPIST-1 travelers.

There is a chance, though, that the outer planets could be frozen instead, if they didn’t have as much water to begin with. But the best hope for a truly Earth-like planet seems to be TRAPPIST-1e, which orbits far enough away that it might still have liquid water on its surface. Then again, this work is hypothetical.

We don’t actually know what kind of atmospheres these planets started out with, or if they’ve always had the orbits they do now. But the study does offer clues about what future observations could look out for, and what other planets we should focus on in the search for Earth-like worlds. So even if models aren’t as directly helpful as telescopes, they can still teach us a lot.

Thanks for watching this episode of SciShow Space News! If you want to learn more about the InSight mission and how it landed, you can watch our news episode from last week. It’s kind of like watching the beginning of a movie already knowing that it has a happy ending.

And if you want to help us keep bringing you the latest space news, you can go to patreon.com/scishow. [♪ OUTRO].