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  • Over the last 50 years, we've sent tons of cool spacecraft to Mars.

  • Flybys, orbiters, landers, roversit seems like we've done everything.

  • Still, there is one kind of mission we haven't done yet: No Mars mission has flown through

  • the airbut that might change in just a few years.

  • Nothing's final yet, but engineers are experimenting with the idea of including a drone, called

  • the Mars Helicopter, on the upcoming Mars 2020 rover.

  • Mars 2020 is NASA's successor to Curiosity, and it's expected to launch inyou guessed it — 2020.

  • It has a similar design to Curiosity and will also study potentially habitable environments.

  • It will also select and package samples we could return to Earth on a future mission.

  • Adding a helicopter could help this rover overcome one of Curiosity's biggest problems:

  • It just doesn't go that far.

  • Curiosity's been on Mars for over five years, but in that time, it's only driven about

  • 17.5 kilometersor an average of less than 10 meters per day.

  • Part of that is because the rover stops and studies things, but it's also because driving

  • a rover on another planet is pretty dang hard.

  • Radio communication with Mars takes anywhere from 8 to 48 minutes round-trip, depending

  • on where Earth and Mars are in their orbits, so mission controllers can't just drive

  • Curiosity Mario Kart style.

  • It can steer itself across simple terrain like a self-driving car, but it still needs

  • to stop every now and again to get input from Earth.

  • And there are some kinds of rocky or difficult terrain it just can't handle.

  • Picking Curiosity's path isn't always the easiest, either.

  • To decide where it should go, engineers rely on pictures from the rover and from satellites

  • in orbitbut Curiosity's cameras can only see so far.

  • And the satellites have a top-down view, so they can't always see the true shape of

  • surface features.

  • If Mars 2020 could launch a drone to scout out the area ahead, it could anticipate obstacles

  • and identify the most interesting things to study.

  • And someday, a Mars helicopteror Marscoptermight even be able to explore places a

  • rover couldn't reach, like small channels or cliffs.

  • This all sounds like an amazing idea, but there's a big problem: Mars is not a very

  • good place to fly.

  • Helicopters stay in the air because they experience lift, or more pressure underneath them than above them.

  • And the more dense the air is, the more lift your helicopter can get, because there's

  • more air molecules for it to push against.

  • The problem is, Mars' atmosphere is really thinlike, less than a 60th the density

  • of Earth's atmosphere at sea levelso it's a lot harder to create lift.

  • But good news: There's less gravity so that's one thing working in favor for us but it is

  • not enough to counteract just the lack of molecules to push against.

  • For this to work, engineers would have to give their Marscopter extra long rotor blades.

  • Basically, this would let the helicopter push against more air molecules at once, even if

  • they're spread farther apart.

  • To carry just 1 kilogram across the Martian surface, the Mars Helicopter would need rotors

  • more than a meter across, which is a lot bigger than your neighbor's photography drone.

  • And that doesn't mean the drone could carry one kilogram of samples, either.

  • Everything, from the rotors to the flight computer to the solar panels, would need to

  • add up to a kilogram of mass.

  • But amazingly, getting airborne might actually be one of the easiest parts of a Mars helicopter.

  • Remember that communications delay between Earth and Mars?

  • Well, unlike a rover, which can sit around and wait for instructions, once the Mars Helicopter

  • is airborne - clock's ticking.

  • It would probably fly for 2 to 3 minutes and could cover up to half a kilometer of terrain

  • but since we wouldn't be able to steer it in real-time, every second of that would

  • have to be on autopilot.

  • It would have to take off, judge the wind speed, fly in the right direction, take pictures,

  • and find a safe place to land, all in 180 seconds or less.

  • That might seem like a ton of work, but it could come with a big payoff.

  • NASA engineers estimate having a Mars Helicopter could help a rover like Mars 2020 travel three

  • times farther than Curiosity in a dayand when you're talking about multi-billion

  • dollar missions, tripling efficiency is a pretty sweet deal.

  • As a bonus, all those extra near-surface images would be really helpful for scientists studying Mars.

  • You'd get a mission that could study not only more targets, but better ones, and that's

  • a heck of a good thing for exploration.

  • So far, NASA has already tested a prototype of the helicopter design, but they'll need

  • to do a lot more work before we're ready to start zooming around.

  • Since Mars 2020 is expected to launch in less than three years, hopefully we'll be hearing

  • more about it soon.

  • Thank you for watching this episode of SciShow Space which was made possible by our Patrons

  • on Patreon who pay so that everybody gets to watch it for free, except for them.

  • That's a wonderful thing that you do.

  • We really appreciate it.

  • If you would like to help make episodes like this an be one of those people you can go

  • to patreon.com/scishow.

  • And if you want to help us out by watching and by sharing that's also great, we're

  • at youtube.com/scishowspace .

Over the last 50 years, we've sent tons of cool spacecraft to Mars.

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美國宇航局或將向火星發射直升機 (NASA Might Send a Helicopter to Mars)

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    林宜悉 發佈於 2021 年 01 月 14 日
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