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  • NASA's rovers on the surface of Mars are revealing answers to some of the biggest questions

  • about our nearby planetary neighbor.

  • And driving this roverthat is, on average, 225 million kilometers away from Earth

  • requires robust technology and years of development.

  • And it's about to get even more advanced with Mars 2020.

  • VANDI: Even though the rovers do so much,

  • the computing power we have on board is actually fairly limited.

  • The average phone a person carries has far more computation than we have onboard the rover.

  • And the reason is because there's a lot of radiation,

  • so we have to use computers that are radiation-hardened.

  • Dr. Vandi Verma has worked for over eleven years developing and operating Mars rovers

  • at NASA's Jet Propulsion Laboratory.

  • VANDI: To send the commands to the rover, we send a fairly compacted set of instructions.

  • When we uplink the sequence to the rover, everything goes through the Deep Space Network.

  • And to get the data back, we transmit it to orbiters, which are actually just in Mars orbit.

  • And then those orbiters transmit it through the Deep Space Network.

  • In fact, we actually have programs on our phones

  • so that whenever the data comes down, you get a little summary.

  • We have a lot of different ways we parse the data, summarize it

  • and depending on what happened, we may dig into a particular area more or less.

  • While we're doing all this, the science team is having a discussion

  • on what to do next.

  • Given the distance between Mars and Earth, NASA can't joystick the rover's every move.

  • So rover planners like Dr. Verma have to map the rover's entire day of sequenced movements

  • perfectly.

  • VANDI: The biggest concern is, 'is the rover going to be safe?'

  • There's imprecision in the data, and in the positioning.

  • So you have to take into account that, 'I am placing this delicate lens

  • within proximity of this other rock. If it was off by five millimeters, is that a hazard?

  • That's sort of what we look for, are those situations.

  • It's a lot of fun.

  • Over the last 20 years, each mission has built on its predecessor,

  • enhancing the critical engineering and design of rovers like Sojourner, Spirit,

  • Opportunity, and Curiosity.

  • And Mars 2020 will be no exception.

  • VANDI: With Opportunity, we were coming across sand a lot more on Mars.

  • We had a situation where the rover was driving along,

  • and by the encoders, as you measure,

  • it's thinking it's covering all this distance and it kept on moving

  • but it's just embedding itself deeper and deeper and deeper.

  • Based on that, we developed the visual odometry technique,

  • which allows us to use cameras to take an image,

  • take another image, and if the rover hasn't moved we'd be able to see that the features have not moved

  • between those images.

  • For 2020, we wanted to be able to drive even more precisely,

  • and we needed to do visual odometry even faster.

  • So we now have a dedicated computer, so that it's so fast

  • that we don't have to think about it.

  • Now this allows scientists to get into more challenging terrain.

  • Mars 2020 will also include a series of major firsts.

  • VANDI: After we land, we're going to deploy this helicopter

  • which is as large as the size of a softball.

  • It'll fly for short durations and it's solar powered,

  • and we'll be able to get data from it.

  • So this is the first time we've had a helicopter on Mars, and that will be really exciting as well.

  • And perhaps the most exciting step will be bringing extraterrestrial samples back to Earth.

  • So what's really incredible with Mars 2020 is that we're going to collect a core this time of the sample.

  • The rover will store the sample cores in tubes and deposit them at precise coordinates,

  • known as sample cache depots.

  • Detailed maps will be provided for future missions to retrieve them and return to Earth.

  • VANDI: And once we get that sample on Earth,

  • it's going to be quite incredible.

  • And then they will actually be sent to labs all over the world

  • and it'll probably be decades that they will be analyzing that.

  • Mars exploration has come a really long way.

  • We now know about seasons on Mars;

  • we know how methane migrates.

  • So there's so many ways in which

  • the history of Mars and Earth are so intertwined.

  • What is it that caused Mars to today be this arid environment,

  • and how does that relate to Earth, which is teeming with life

  • and this beautiful blue planet?

  • And that has opened up a whole new area of science and understanding

  • and allowed us to analyze these details very carefully.

  • Humans are definitely someday going to be on Mars,

  • and the rovers are making discoveries that will make that possible

  • and make decisions on how we do that.

  • This episode was presented by the U.S. Air Force. Learn more at airforce.com.

  • For more episodes of Science in the Extremes, check out this one right here.

  • Don't forget to subscribe, and come back to Seeker for more episodes.

  • Thanks for watching!

NASA's rovers on the surface of Mars are revealing answers to some of the biggest questions

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火星想像(How NASA’s Rover Team Reimagined Mars 2020)

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    joey joey 發佈於 2021 年 04 月 14 日
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