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  • The Voyager 1 space probe is the furthest man-made object from Earth, and the fastest.

  • But right now, it is moving towards us.

  • Relatively speaking.

  • This is the control room for NASA's Deep Space Network

  • and the scientists here still listen for the signals that Voyager is sending.

  • Deep Space Network is a collection of antennas around the world

  • that we use for tracking deep space missions.

  • We provide commands to the spacecraft, so y'know, “turn left at the next corner

  • kinds of things, right?

  • Little more complicated than that.

  • Turn the instrument on, turn the instrument off, software updates.

  • The most important reason for sending the thing out there

  • is to get the science data back, and so the instruments are taking

  • visible pictures, infrared pictures, measuring particles in the case of Voyager.

  • We need to get that data back down and distribute it to the scientists.

  • The Deep Space Network's three stations cover the whole sky.

  • Any mission more than 30,000 km away from Earth

  • is visible to at least one station all the time.

  • Geostationary orbit, where we keep most of our communication satellites,

  • is further away than that.

  • We really have three complexes around the world:

  • Madrid in Spain, Goldstone here in California, and the Canberra complex in Australia.

  • We typically don't track things that go over the pole because

  • the types of missions that we deal with are in deep space

  • and tend to be in the ecliptic.

  • If you look at the solar system, where the Sun is,

  • and where the planets are that are revolving around the sun,

  • they all tend to be more or less in one plane.

  • That launch along the plane of the solar system, along the ecliptic,

  • is the reason that Voyager is getting closer to Earth right now.

  • Yes, Voyager is always moving away from the sun, but sometimes the Earth's orbit

  • means that our planet is travelling in roughly the same direction only faster.

  • So we're catching up.

  • Of course, we'll get pulled back in our elliptical orbit

  • so it'll even out when we go back the other way.

  • In terms of checking in with spacecraft, I think with Voyager for example,

  • we probably downlink from them almost every day.

  • Because again, there's a lot of good data, but when you are only coming at 160 bits per second,

  • it takes a long time to get that data off the spacecraft.

  • The signal has to be, in some sense, above the noise level for us to see it.

  • You first of all just try to filter the noise out as much as possible,

  • just from a frequency standpoint.

  • My signal occupies this much spectrum in frequency,

  • I don't want to let in any more noise than what's there.

  • I want to correlate the signal that's coming down

  • with what I think that signal looks like.

  • You got to take advantage of what you know about the signal

  • and use those characteristics as best you can to extract it from the noise.

  • Voyager 1 is carrying radioisotope thermoelectric generators, RTGs.

  • It's powered by radioactive decay.

  • And there's enough power there to last until around 2025.

  • After that, the craft will go dark, carrying a message forward into interstellar space

  • forwell, we don't know where, or when, or even who.

  • If there was enough light being bounced off of it,

  • you might be able to see it with a telescope, but it's so far away, and so dim,

  • without a radio signal coming from Voyager at all,

  • there's no way that we, the DSN, would be tracking it.

  • And so I think that's pretty much the end, once it goes dark.

  • Thank you very much to all the team at NASA, the Jet Propulsion Laboratory,

  • and here at the Deep Space Network.

  • Pull down the description for more about them, and about their missions.

The Voyager 1 space probe is the furthest man-made object from Earth, and the fastest.

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旅行者1號現在離地球越來越近了 (Voyager 1's Getting Closer to Earth Right Now)

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    林宜悉 發佈於 2021 年 01 月 14 日
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