What Is The Deep Space Network & How Does It Work?

What Is The Deep Space Network & How Does It Work?

Remember when we saw those really cool images
of Pluto? How did a dwarf planet send those us all the way from space? Hey guys, Julia here for DNews. The first
spy satellites had actual film cameras onboard, with canisters equipped with parachutes to
get the photos back to the ground, but as we advanced, satellites began using digital
cameras, on-board computers and radio waves to send data long distances. Today, the MSL
Curiosity rover is on Mars, Juno is almost to Jupiter and Cassini is visiting Saturn…
All of these missions are constantly sending data to scientists back on Earth, but how?
It’s all thanks to the Deep Space Network. It became clear really early on in the space
program, that scientists needed a way to constantly be able to communicate with their satellites.
Unfortunately for them, the Earth rotates, and as it does, satellites appear and disappear
So, 50 years ago, NASA’s JPL began the Deep Space Network. Three sites were selected to
receive data from Space, one in California, one in Spain and another in Australia — 120
degrees apart so together they could see the whole sky 24 hours a day. On each site an
array of massive satellite dishes ranging from 24 to 70 meters in diameter were constructed.
This is the most powerful and sensitive communication system in the world. The 70-meter antenna
is able to hear quote “a whisper from a billion kilometers” away. Now, because of launch weight restrictions
and power limits, broadcast equipment on spacecrafts has to be light, so engineers are forced to
use relatively low-powered transmitters — like, 20 watts (that’s way less than the average
incandescent light bulb). And it gets weaker as it travels through space. By the time the
signal reaches the dish, it can be “20-billion times less than the power needed to power
a digital watch.” When a signal wave hits the dish, it’s reflected to a highly sensitive
receiver at the center — and put through a crazy powerful amplifier. The amplifiers
are cooled to near absolute zero, to minimize electrical interference from the equipment
itself. So, because of their position on the globe,
no matter where the satellites are, at least one DSN dish will be able to hear the broadcast.
Signals from near-Earth missions are strong, and can be picked up relatively easily. For
deep-space missions, it’s a bit harder. To strengthen the signal, probes in space
use both low and high-gain antennas. Low-gain antennas are like ones used at local radio
stations — they spread their power in every direction at once. The tiny microwaves of
a high-gain antenna are focused, like a laser, so the signal strength is stronger when it
reaches Earth. If the spacecraft points it’s high-gain antenna at Earth, the DSN can pick
it up. The Earth-based antennas also have to move here on the ground. High-gain antennas
are extremely directional, because you don’t want to lose at data stream! So, the ability
to point directly at what we’re trying to communicate with is super important. But even
if the spacecraft is not pointed at Earth, the DSN can still “see” the low gain signal.
According to NASA, this is what makes low-gain antennas useful for things like emergencies. This Earth-sized marvel of engineering is
not only practical for space exploration, but necessary! Without each of these three
sites, there would be a time when spacecraft would be on their own, in the dark, in the
vastness of space. The Deep Space Network lets them phone home whenever they need to.
And you can see this communication happening right now!

Author: Kevin Mason

100 thoughts on “What Is The Deep Space Network & How Does It Work?

  1. How do the Voyager probes know where earth is to point their antennas to?
    In principle it can be calculated. But since they were launched in the 70's I find it doubtful that such a calculation would still be accurate.

  2. "Not enough to power a digital watch." What about this 'Low gain' signal? Can energy be transmitted wirelessly with low gain radio waves?

  3. It is called spread spectrum technology, lady. We don't worry about the Signal to Noise Ratio. we go under the noise strength of additive white Gaussian noise and send a burst transmission with power distributed over a very wide frequency band with. Sigh. This is what happens when Physicists try to explain Information Theory and Coding. 🙁

  4. I think the next question is how does a satellite know where Earth is, so that it can point their directional antennas to us.

  5. As I said on the previous video – do something about that glare. Loose the monitor, loose the glasses, change the glasses to something less reflective – doesn't matter, just do something. It is very distracting, and you do have some cool stuff to tell us.

  6. Hi Julia. Very good video. Keep it up. BTW I want to know something more about global cooling. Could you please make a video of it?

  7. instead of commenting about her appearance I am wondering if gaining more giant antennas will help with getting more information faster

  8. satelite dishes can hear a whisper form 1000.000.000 km away
    well that solves the whole 'in space no one can hear you scream' problem.

  9. "Curiosity rover"…inserts picture of Spirit or Opportunity instead… ^_^ other than that great video. I learned something new which is what Dnews is all about.

  10. I'm curious what kind of data protocol they use. For my terrestrial based Internet, if I get even the slightest interruption my web page can crash or my download will restart. Which down here happens too rarely to matter, except for few places. In space the satellite could be unresponsive for days at a time; it could be behind another planet, solar winds can jam the signal, or it could just be so far away that signal is coming in at dial up speeds. And when it comes to downloading 4K images, I imagine starting over again until they can download it in one go would be highly improbable. So I'm curious what they do to make it error proof?


  12. NASA needs to have its budget doubled to develop new tech with the help of the US Navy.  With Space Based Power NASA can build more powerful spacecraft that can send data faster from active instead of passive research instruments.  One future spacecraft was the JIMO probe to Jupiter, now cancelled.  This Power can also power the ion and VASIMR engines of manned and unmanned spacecraft to places beyond LEO.  tjl

  13. If multiple satellites broadcasted the SAME signal regardless of signal strength, would it still reach the satellite dish?

  14. the glasses are only to make what she is saying believable. so NASA can locate a tiny satellite 100s of millions of miles away aka pluto and hear a whisper from a billion miles away, but can't locate the leader of I S I S. I would think this 10G not 4G communication technology would be available on earth after being tested in space for 10 years.

  15. Keep in mind that her mentioning of “whisper” is referred to SIGNAL! People are taking it literally. That’s why these people need to explain clearly when they make videos about science because there are always some people who takes it literally.

  16. Nice try… I think there is some martian guy ups Person.. out there with the voyager device sent buy ASAN like in star truck the search for spock who is coming to this planet ya ya for sure looking for the maker

  17. The deep space network is not usually known to the space science field but thought myself loves space as top favourite science topic

  18. The problem I have is the fact that they put the California array right next to and even inside the perimeter of a very large military training area where military personnel are using radios on multiple frequencies all the time…and yet there are signs right outside the entrance to the C-DSA that warn people to turn off any and all electronic devices. what is the point? They may not be on the same frequency(s) but there is such a thing as frequency hop, and localized stratospheric deflection and interference. So what if E.T. or other deep space telemetry is trying to phone home on or near those freqs? It's typical government stupidity. Like where I work…a military gunnery range right square in the middle of a wildlife conservation area. show me the logic.

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