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  • When it comes to landing spacecraft on planets, or moons, or back here on earthMars sucks.

  • There's a lower success rate landing on Mars than on Venus, the moon, the earth, even

  • Saturn's moon Titan.

  • And in large part, this is because Mars's atmosphere is in the perfect goldilocks zone

  • of being a total headache.

  • On the moon (or an asteroid) you can use lightweight spacecraft made essentially out of tinfoil

  • because there's no air to cause drag or pressure or heat.

  • Essentially, you save weight not having heat shields or thick walls, but need to use rockets

  • to land in what's called a “powered descent.”

  • On earth, or Venus, or Titan, there's enough air that you can land largely unpowered, first

  • by slowing down with a heat shield and atmospheric drag, and then with parachutes.

  • So you use a lot of weight for heat shields and walls and parachutes, but don't need

  • big rockets or lots of fuel to land.

  • However, the air on Mars is literally the worst of both worldsthick enough that

  • you actually have to deal with it with heat shields and walls, but thin enough that it

  • doesn't help you slow down much and you also need to use rockets.

  • Mars is simply a challenging place to land a spacecraft, which is why we've tried so

  • many different and crazy techniques for landing there: we've landed landers and rovers using

  • retrorockets, in inflatable bouncy airbags, by being lowered from a hovering sky crane

  • all of which ALSO used heat shields and parachutes and rocket powered descent before

  • the last stage of landing.

  • And space agencies are testing other crazy things like giant supersonic parachutes and

  • inflatable innertubes around landers to increase their surface area and help them slow down

  • more in the thin air before landing (probably still with rockets, or sky cranes).

  • Yes, you heard that rightit's possible that when the first humans land on Mars, we

  • may do so in an inflatable donut.

  • Or we'll just skim at a really low angle past the tops of mountains for a really long

  • time to slow down enough...

When it comes to landing spacecraft on planets, or moons, or back here on earthMars sucks.

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