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Illustration: Sarah Grillo/Axios

The rovers and orbiters studying Mars are being tasked with answering the persistent questions that remain about the Red Planet, decades after NASA sent its first missions to the world.

Why it matters: New spacecraft recently sent to Mars will help NASA and other space agencies fill in gaps in knowledge, moving them ever-closer to finding out whether the world once played host to life.

  • But answering questions about Mars' past and its potential for life will likely take more spacecraft, and possibly even human missions to solve.

Driving the news: A study published this month suggests much of Mars' water may have been absorbed into the ground, not lost to space, as scientists have thought for decades.

  • Thanks to this new study, scientists have been able to start to square the planet's geology with what they know of how its atmosphere was lost, painting a clearer picture of why the world is now the barren one we see today.

Yes, but: Not all questions about Mars can be quickly answered with current data.

  • Perhaps the most pressing question has stood for centuries: Has life ever existed on the Red Planet?
  • NASA is just scratching the surface of answering that question using its Perseverance rover — the first mission dedicated to hunting for past Martian life — which made it to Mars in February.
  • Even that rover likely won't be able to find signs of life on its own, however. Perseverance is expected to cache samples for a return to Earth on a future mission that will allow scientists to use high-powered tools to analyze the samples.

The big questions: Although scientists know Mars was once habitable — at least for microbial life — it's still not clear that the environment could have supported diverse and abundant life as we see on Earth.

  • While the planet did have lakes and rivers, researchers don't know exactly how warm the planet was.
  • "There are a lot of basic things we still don't know, like how warm or how wet was ancient Mars? Was it a cold, icy barren world or was it this warmer, wetter ... warm desert planet?" Purdue University planetary scientist Briony Horgan told me.

Rovers on the planet have also found the world is scattered with layered rocks, but no one is quite sure how they formed.

  • Scientists' best guess at the moment is these layers formed through erosion, wind, water and ice. But we don't see rock layers like this on Earth because they're destroyed by plate tectonics, which don't exist on Mars, Horgan added.

The intrigue: Sending rovers and landers to Mars has actually complicated scientists' understanding of the Red Planet.

  • "When you only have one data point, it's easy to make a model that fits that one data point, but when you have 50 data points, it's a lot harder to find the right model to fit those data," NASA Mars researcher Abigail Fraeman told me.

What's next: Human missions to the Red Planet could one day help resolve these mismatches between data beamed back from spacecraft in orbit and rover-collected data from the ground.

  • Having people on Mars would allow scientists to easily move to other parts of the planet to search for interesting rocks without the planning and guesswork that goes into a rover's roadmap, experts say.

Go deeper

28 U.S. citizens depart Afghanistan on Qatar Airways flight

Passengers board a Qatar Airways aircraft bound to Qatar at the airport in Kabul on September 10, 2021. Photo: Aamir Qureshi/AFP via Getty Images

The State Department on Saturday confirmed that a Qatar Airways charter flight left Kabul on Friday with 28 U.S. citizens and seven lawful permanent residents on board.

The big picture: Friday's flight is the third such airlift by Qatar Airways since the Taliban takeover of Afghanistan, AP reports.

Updated 40 mins ago - Politics & Policy

Smaller than expected "Justice for J6" rally met with large police presence

Police officers watch as demonstrators gather for the "Justice for J6" rally in Washington, D.C., on Sept. 18, 2021. Photo: Andrew Caballero-Reynolds/AFP via Getty Images

A few hundred demonstrators were met by a heavy law enforcement presence on Saturday at the "Justice for J6" rally outside the fenced-off U.S. Capitol, AP reports.

The latest: About 400 to 450 people were inside the protest area, excluding law enforcement, U.S. Capitol Police said.

DHS to increase deportation flights to Haiti from Del Rio

Migrants walk across the Rio Grande River carrying supplies back to a makeshift encampment under the international bridge between Del Rio, Texas, and Acuña, Mexico. Officials are struggling to provide food, water, shelter and sanitation, forcing migrants to cross the Rio Grande several times per day for basic necessities. Photo: Jordan Vonderhaar via Getty Images

The Department of Homeland Security on Saturday announced plans to ramp up deportation flights to Haiti out of the small Texas border town Del Rio, starting as soon as Sunday.

Why it matters: Reports have emerged of more than 10,000 migrants, primarily from Haiti, crowded in a temporary camp under the international bridge in Del Rio. Hoping to find refuge in the United States, they've had to bear with filthy conditions and the scorching sun for days, per an NBC News affiliate.