Questions tagged [communication]

Questions regarding information transfer between spacecraft, and between spacecraft and Earth.

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4
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2answers
288 views

Quantitatively, why will optical communication be better than X-band for deep-space communications?

In a question about communicating with Voyager, an answer asserts: [70 meter dish antennas deployed in space] just isn't done, and it probably won't be, since optical communication is definitely ...
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Has the Curiosity rover ever communicated directly with Earth via its high-gain antenna? Signal strength & data rate?

In the question How does Curiosity know how to point and move it's high gain antenna in real time? I show an image of the hexagonal, articulated high gain antenna on the curiosity rover, as well as ...
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How well can Voyager 1 separate Earth signals from Solar noise these days?

This is a follow-up question to Can Voyager 1 receive signals from Earth? this and this answer. UPDATED: see additional information and discussion below. As it continues to move farther from the Sun, ...
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Do antennae on the ISS have to constantly move to maintain data links?

In this question and answer pair I see that the ISS can maintain data links to earth through direct access to ground stations as well as through the TDRSS geostationary satellite network. What kind ...
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Has DSS-43 ever been used in high power mode (>>20 kW) for an emergency situation?

This answer notes that while most Deep Space Network transmitters are 20 kW of power or less, one dish (DSS-43 in Canberra) is equipped with a transmitter capable of 400 kW. As described in 101, 70-m ...
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How did NASA achieve their live TV broadcast in 1969?

In 1969, NASA not only went to the moon, but broadcast the whole thing live on TV. How did they achieve the TV broadcast? What technology did they need to use to send a video and audio signal from ...
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378 views

Will there be "Near Space" Ka-band allocations for TESS?

update: More information in Phys.org's news item TESS mission to discover new planets moves toward launch, including a video of the telescope array's final assembly. Also see GSFC's TESS page. The ...
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Will future deep space optical communications "ground stations" actually be in space, or on the ground?

Deep space communications ground stations are on the ground because their transmit and receive electronics alone is bulky and heavy, not to mention their 34 and 70 meter dish antennas! But those ...
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Will the Tesla Roadster return any telemetry?

Is there any equipment fitted to the Tesla Roadster to send signals back to Earth, even for a short time after launch?
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How many antennas does Kurs use in toto, and what are each of their functions?

I learned about the Kurs docking system in this answer, then found out what they looked like in this and in this answer. Those images show several tiny dish antenna structures sticking out from ...
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1answer
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When does the ISS have a loss-of-signal?

The ISS has a camera mounted streaming live video from space (HDEV). From time to time, there is a blue screen visible, which is noted to be during times of "loss of signal". What exactly defines a "...
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Can anything at Mars speak 900 MHz ZigBee besides Ingenuity helicopter and Perseverance rover?

Interest is piqued by What could be strong arguments against Ingenuity following Perseverance at a safe distance when the flight test program has been a success? Question: Can anything at Mars ...
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Frequency responses of Voyager's S-band high gain antenna's feed-horn and receiver front end & IF?

I'm working on this question. This is the farthest (known) communications link humans have ever engineered - an one node is running in deep space on 40 year old technology. Pretty amazing! In the ...
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Are there plans or a program for an optical relay pathfinder for deep space?

In Glenn Research Center's Richard Reinhart's slides Space Communication and Navigation TestbedCommunications Technology for Exploration for the 2013 ISS Research and Development Conference I saw an ...
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How does Voyager 1 send signals to Earth?

I recently studied that Voyager 1 has traveled a distance of 125.01 AU as of August 3rd, 2013. I wonder, how would it be able to communicate with the Earth? How much time does it take for the signal ...
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How hard is it to receive direct signals from vehicles on the surface of Mars, and has anyone other than the DSN done so?

Almost all communication from vehicles on the surface of Mars is relayed by spacecraft in orbit around Mars. However vehicles on the surface do communicate directly with Earth. This communication, ...
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What are the prospects for comms with cubesats using "normal" internet connections?

Can a cubesat in orbit be operated like a R/C airplane in real time? edit: if the link here and the end aren't clear, I'm interested in the ease and convenience of access, the frequency of possible ...
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How are the tiny spacecraft proposed by Project Starshot supposed to communicate with Earth?

Between power limitations and aperture-limited diffraction I just can't see how it's possible.
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Could "live" video be transmitted from Mars?

With the approach of InSight to Mars today, and the two cubesats watching it, much is being made about seeing "Live Video" from the cubesats. I'm pretty sure that simply can't happen, but I'm ...
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How does NASA get information from space probes?

So I have briefly gone over answers to how things are stored as from this answer: https://space.stackexchange.com/a/2273/1247 but how is the information sent back? I'm thinking of probes like the ...
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918 views

What, if any, mechanisms prevent unauthorized commands?

Since deep space probes and satellites receive commands from Earth via radio, what prevents unauthorized commands from being accepted by such devices? For deep space probes, the required power of ...
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What (actually) makes Iridium "the world's only truly global mobile satellite communications company"?

In this article about how the SpaceX anomaly will affect Iridium it says: In its official website, Iridium describes itself as "the world's only truly global mobile satellite communications company....
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Why is Queqiao's dish antenna so big? (Chang'e-4 relay satellite) Largest ever on/near the Moon?

Source: Chinese language blogpost The NASA Spaceflight article Queqiao relay satellite launched ahead of Chang’e-4 lunar mission describes the communications relay satellite that will be used to ...
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What would it take to get a message to another star?

Let's assume that we've somehow detected the existence of an extraterrestrial civilization through "passive" means, such as detecting a suspicious exoplanetary atmospheric signature. We're now hoping ...
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How big is Earth's sphere of broadcast influence?

The question Interstellar eavesdropping points out that we have been broadcasting to space for a long time, currently we are approaching a century. This means every star system in within 100 light ...
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439 views

Does man send any signal to attract aliens?

Does man send any signal (such as electromagnetic radiation) to space to attract aliens?
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381 views

Deep Space Network time budgets per spacecraft - is such statistics available?

Is statistics available about time consumed by different spacecraft for communication wint NASA Deep Space Network (DSN)? It would be interesting to compare which space missions are more downlink-...
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1answer
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What will China's new "space station" in Argentinian Patagonia be used for?

The New York Times (fairly strongly worded) article From a Space Station in Argentina, China Expands Its Reach in Latin America describes a "space station" or base equipped with (among other ...
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Why was SpaceWire designed with nine wires?

I just learned about SpaceWire in this great answer about the slip-ring rotating electrical connection between its solar panel and attached sun-pointing instrumentation, and the body of the craft with ...
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How to design a ground antenna for sending & receiving from a satellite?

Let's suppose there is a wifi router or a cell phone or similar transmitter in an orbit of 3000 km. How could one make a dish antenna to connect and receive the signal from that wifi router or cell ...
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Why will radioastronomy telescopes be used to listen to InSight's entry into Mars' atmosphere instead of DSN?

The JPL News article How NASA Will Know When InSight Touches Down is interesting and worth a read. It says that during the atmospheric entry, descent and landing, the Mars InSight probe will be ...
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Can Voyager 1 receive signals from Earth?

There are answers about Voyager 1 sending messages to Earth, but can Earth still send signals to Voyager 1? I am just wondering if the signal of the Sun will eventually overcome the signal from Earth ...
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How did NASA prevent third parties from spoofing Apollo communications?

The Apollo crews transmitted footage to Earth using SSTV, a ham radio technique that amateurs and pirates can use to send similar messages around the world. Did NASA have any technical ...
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How did the communication work between the SpaceX Tesla and Earth?

With a Tesla launched in space and HD cameras put on it, I can imagine its not easy to receive a signal from that slowly spinning, multiple ten-thousand km away new artificial object in our solar ...
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1answer
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What was the last message to Opportunity today (13 Feb '19)?

Several articles have mentioned that the last ever commands were sent to the unresponsive Opportunity rover today by NASA. Now, I know that it wasn't a verbal message, but was there anything digital ...
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How precise must be the antenna orientation to communicate with a deep space probe?

I guess that everyone is familiar with the problem of aligning a TV satellite dish: some degrees off and the signal you desire is gone. How sensitive is communication with deep space probes to this ...
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Interstellar eavesdropping

For about a century, humanity has broadcasted noise to space in the form of TV broadcasts, radio, etc... The nearest star is 4.242 light-years away, so for about 90 years, aliens -- if they exist in ...
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How much power loss does the LLCD suffer in transit?

Space.com writes to say (freeform improved quote): The LLCD (Lunar Laser Communication Demonstration) space terminal is designed to beam data from the moon at a rate six times faster than the best ...
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952 views

How many earth stations had astronauts on-site during John Glenn's orbit in Friendship-7?

The Washington Post just republished it's February 21, 1962 article covering the launch, Earth orbit, and safe re-entry and recovery of (Senator) John H. Glenn, in recognition of his service and ...
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What does the ISS Mission control center do?

This related question asks about Mission Control's responsibilities during a hurricane. But there's a more general question underneath: what do the people in Mission Control do, what are their ...
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Equipment needed to contact ICE/ISEE3 Spaceraft

A few days ago, I was reading the wikipedia entry for the International Cometary Explorer (ICE) / International Sun-Earth Explorer 3 (ISEE-3) satellite, that was launched August 12, 1978. Down near ...
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Are Martian winds as strong as portrayed in "The Martian"?

I read Andy Weir's "The Martian" and saw the movie, which is supposed to be realistic science fiction. And I immediately saw a couple of huge flaws, one of which I'd like to tackle with this question: ...
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How can we form a data-communication relay chain for deep space exploration?

The power that deep space probes have allows an RF communication capacity of a few kbps from a range like Pluto-Earth. If we go into optics, the range will be better. But, of course, we want to send ...
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Would plasma sheathes from reentry heating block optical/UV communications as well as radio?

During reentry, it's routine for the ionized atmosphere surrounding the spacecraft to cut off radio communications for a certain period. As far as I know, this can't be avoided, except perhaps by ...
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What technology will SpaceX's StarLink satellites most likely use for sat-to-sat linking?

The question How does SpaceX plan to make money with StarLink Broadband? has got me thinking about how the satellites will link to each other. Wikipedia says it's something greater than 10,000 GHz and ...
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What are the main sources of radio noise & interference limiting deep space data rates and availability?

Let's call "radio" anything electromagnetic below 300 GHz (1 millimeter), unless there is a compelling reason to do otherwise. The question How well can Voyager 1 separate Earth signals from Solar ...
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Why was Canberra able to listen to Voyager 2 but not talk to it?

The New York Times's When Voyager 2 Calls Home, Earth Soon Won’t Be Able to Answer explains that because Voyager 2's trajectory has taken it way below the ecliptic, of the three 70 meter dishes in the ...
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What if the Voyagers had remained within the plane of the ecliptic?

On their last big-planet flybys, both Voyager 1 and 2 were given substantial kicks out of the plane of the ecliptic. If this wasn't so, and their flyby's were adjusted to stay within the plane of the ...
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Relativistic effects in space mission communications

How important are relativistic effects in communication with space missions? I am doing some work on Mars Pathfinder and want to know if effects like gravitational deflection of microwaves matter in ...
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Why is Sentinel 3B's dish antenna overwrapped with metallized film?

The Spaceflight Now article Photos: Sentinel 3B satellite prepared for launch from Plesetsk Cosmodrome has of course lots of photos. One of them shows a dish antenna covered with shiny, metallized ...