Questions tagged [communication]

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

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What size are the typical keep-inside boxes of geostationary telco satellites?

Geo sats need station-keeping and the size of their keep-inside box is a design parameter. A smaller box implies more manoeuvres to stay inside the box. All depending on the various orbit ...
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3 votes
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Where to find the network topology of Iridium-Next?

This is my first post on Space Exploration. I'll preface this by saying that I just started learning how satellite communications work from a technical perspective. Until a few days ago I had never ...
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How does the data rate of the Psyche mission's Deep Space Optical Communications (DSOC) system scale with distance?

NASA's Mission Page Deep Space Optical Communications (DSOC) includes the following: Key DSOC technologies developed for the project include: a low-mass spacecraft disturbance isolation and pointing ...
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What kind of signals and encodings were used to send tilt/pan commands to TV cameras on the Moon (up through Apollo)?

This answer to Has anyone in space beyond LEO seen or has anything photographed a non-pointer laser from Earth? shows a frame from video shot by Surveyor 7 on the Moon, looking at Earth, and ...
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Mars at its closest is only a few light minutes away -- are different experiments performed when this happens?

While 3 minutes is not exactly real time, it still seems like remotely-controlled experiments of a different nature can be performed that could not be when Mars is farther. Is this correct, that the ...
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Is it possible for a spacecraft to communicate with Earth when a planet is in the way?

I have just read 2001: A Space Odyssey and despite the fact that the author was quite optimistic about the space exploration capabilities, communication between a spacecraft and Earth was not possible ...
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What is this term in the link budget equation from Space Mission Analysis and Design (SMAD)?

Looking at the 3rd edition of Space Mission Analysis and Design by Wertz and Larson, their equation (13-4) presents the link equation, $\frac{E_b}{N_0} = \frac{PL_\ell G_t L_s L_a G_r}{k T_s R}$, with ...
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1 vote
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Do we use masers, lasers or infrared lasers to send data from deep space back to Earth? If not, why not?

I have posted in a couple of places (including here) about the recent (in the past year) news about future probes, landers, etc. using strong visible light lasers to send data back to us at much ...
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6 votes
3 answers
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How were Intelsat 1 “Early Bird” and Telstar 1's "hundreds" of simultaneous telephone conversations multiplexed/demultiplexed?

When did they stop routing long-distance analog phone calls through satellites? What was the maximum volume at its peak? contains images, sources and descriptions of both The Intelsat 1 “Early Bird” ...
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When cis-lunar Artemis astronauts and folks on Earth communicate via audio (e.g. EVAs) will they still step on each other's words like during Apollo?

It's been fifty years since we've heard astronauts and ground folks talk over each other ("step on each other" in 1970's CB radio parlance). Sitting on the floor a few feet away from our ...
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What is a good SNR value for a chipsat in LEO using bpsk?

My team and I are working on a chipsat and we are planning on launching it to LEO, we've also planned using bpsk. However our use case is a bit different, all we need once it is in LEO is a ...
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Are there any selfies of Curiosity or Perseverance with their high gain antenna deployed and "looking up"?

The Curiosity and Perseverance rovers have high gain antenna arrays on a mechanical arm that can rise up and point towards Earth and communicate directly. Has the Curiosity rover ever communicated ...
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How will the LICIACube cubesat transmit DART impact images back to Earth? What kind of antenna and radio will it use?

MarCO The Mars Cube Ones or MarCOs were 6U cubesats that were deployed in deep space during the InSight mission to observe it during a critical, dynamic period of its mission, in this case the N ...
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What is an "octet" in the context of NASA's LunaNET Interoperability Standard? ("internet on the Moon")

The PDF Draft LunaNet Interoperability Specification, LN-IS Baseline V001 September 2, 2021 (found at https://esc.gsfc.nasa.gov/projects/TEMPO?tab=lunanet) has found its way to the popular press. 4.2 ...
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Tracking of spacecrafts of the Mercury project

In the absence of any communication satellite in 1958, back in Mercury times, how did the tracking centers, which were spread world across, communicated with each other, passed on their data to the ...
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Is it possible for LEO satellites to detect a usable signal from regular mobile phones on the ground?

Background Recently I came across a company called ASTS that claims they will be able to launch LEO satellites with the capability to talk with regular mobile phones. I initially wrote their claims ...
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2 votes
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Modifying Starlink / Dragon for orbital communication

In this answer @uhoh notes: The Starlinks currently have three types of internet-related communication: downwards with customers fixed on the Earth's surface below the satellites (except an ...
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What did Intelsat-1 do in 1990 for its 25th anniversary brief reactivation? Could it be reactivated again? Is there a secret code?

Ouch! The 1960s From This Is What Broadband Satellite Communication Looked Like in 1965 The Intelsat 1 “Early Bird” communications satellite, built by Hughes Aircraft Co., was able to relay 240 ...
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How exactly did ground stations track the early Molniya satellites?

Wikipedia's Orbita (TV system) says: Orbita (Russian: орбита) is a Soviet-Russian system of broadcasting and delivering TV signals via satellites. It is considered to be the first national network of ...
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8 votes
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What is the range of frequencies of a deep space channel?

I've been trying to find the values of bandwidth of each Deep Space frequency channel: band S, X and Ka. In the official NASA's documents only appears the center frequency of each one, but it doesn't ...
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2 votes
1 answer
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What connection do Mars rovers use to send data to Earth?

How do Mars rovers send data back to Earth? Do they have some kind of built in WI-FI routers or is there any other connection?
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7 votes
1 answer
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How deep could a gas giant communications network penetrate?

I have been wondering what type of communication network could you build to communicate as deep as possible into a gas giant such as Jupiter? Which technologies would you use at what depths? One could ...
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7 votes
1 answer
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Why are modern satellite ground station and deep space communications dishes with secondary mirrors almost always Cassegrain?

The simplest dish antennas have a concave reflector and their feed horns at the primary focus which is "up in the air". That has several inconveniences, it's hard to go up there to do any ...
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Currently, how many communications channels can a single DSN dish maintain at the same time? Are there plans to increase this in the future?

DSN NOW screenshot 2021-07-10 at 07:14 UTC DSN NOW screenshot 2021-07-10 at 09:48 UTC The screen shots show Canberra's Dish 35 simultaneously transmitting and receiving, and above it is written MRO, ...
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6 votes
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Cubesat half duplex communication stack

My understanding is that in half duplex transceivers, you are only able to either transmit or receive. In Cubesats using half duplex comms, which part of their communications stack is performing the ...
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How (the heck) is it possible that with China's future 6G satellite network I'll be able to download 1000 movies per second?

The reasonably credible Wall Street Journal has a YouTube channel and the new video SpaceX vs. China: The Quest for Satellite Internet | WSJ says that with Starlink's data rate I can download a 1 Gb ...
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How is Prospero doing now? Was it really heard in 2004 and have there been recent attempts to contact it?

Screenshot from the excellent historical review in Curious Droid video Black Arrow : The Lipstick Rocket - A Very British Space Program with a photo of Prospero or at least a representation thereof. ...
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4 votes
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Tradeoffs between using two 34 m and one 70 m Deep Space Network dish?

Discussion at this answer to Why does DSN sometimes uses two dishes at the same time to receive Voyager-1? include the possibility that in some cases it would be preferable to use two 34 meter DSN ...
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3 votes
3 answers
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Why allow communication with interplanetary spacecraft to be silent for stretches of time; only getting updates on certain days & times of the week?

Communication between planetary bodies in space, e.g. from the moon, or Mars, takes a long time and has many shortcomings, like line of sight requirements. Communication with interplanetary spacecraft ...
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2 votes
2 answers
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How Ingenuity ensures it does not fly away from the range of connection from Perseverance?

There must be a range after which Ingenuity cannot communicate with Perseverance. I am not sure what that distance is. How Ingenuity ensures it does not fly away out of that distance? If inadvertently ...
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5 votes
1 answer
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Could amateur radio operators or others contact the ISS against NASA's wishes?

In real life, but more often in fiction, there are have been a number of examples of "Don't tell the crew" i.e. Mission control finding out about an issue and deciding that for whatever ...
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2 votes
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Specifications of a High Gain Antenna

I am designing a telecommunications device capable of redundant communication from Earth to Saturn's moon Enceladus which ranges from 8 to 11 AU from Earth. I have decided on an X-band high-gain ...
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5 votes
1 answer
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How do the small radio receivers on space probes catch enough of a signal to communicate with us?

From Scientific American, March 2021: Optics. Traveling Photons. Joanna Thompson. Much of today's space communication relies on radio signals. But these diffract and broaden as they travel, as ...
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8 votes
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Is there anything that could speak 900 MHz ZigBee that could hear Ingenuity helicopter besides the 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, or ...
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What could be strong arguments against Ingenuity following Perseverance at a safe distance when the flight test program has been a success?

This answer to the question "How long could the Mars helicopter Ingenuity keep up with the Perseverance rover if it wanted to?" reasons that indeed it could for years ! But according to the ...
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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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-1 votes
2 answers
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Has anybody ever picked up the signal transmitted by a successful Mars lander or rover sent by the United States? [closed]

It is known that on February 4, 1966, the picture transmitted from the Moon by Luna 9 was intercepted by UK. The question is, has anybody ever picked up a signal transmitted by a successful Mars ...
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Was Dart antenna tested using a DSN antenna located in Australia?

So recently a tweet by a bot which tracks communications by the Deep Space Network stated that: DSS 43 receiving data from Double Asteroid Redirection Test at 312.5kb/s. IN LOCK IN LOCK 1 TURBO 11:11 ...
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3 votes
2 answers
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How did Argentina, Namibia, and Pakistan help China monitor and communicate with Chang'e 5?

At the end of The Hill's article Chinese official unveils future moon mission plans including possible lunar base it says: The most recent Chang'e 5 probe was assisted by the European Space Agency, ...
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3 answers
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Main differences between 5G and Starlink? [closed]

I wonder who is better in terms of whole if considered. Speed, latency, reach, accessibility and affordability.
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4 votes
2 answers
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GMAT - Locating inter-spacecraft contact instead of spacecraft to ground station

GMAT implements two "event locators" that find eclipse times and line of sight intervals. However, this only lets you analyse data between a ground station and a spacecraft. Is there a way ...
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2 votes
1 answer
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How should we point our SpaceX Starlink ground transceiver antennas?

I don't have one of course, but I see that the Starlink ground transceiver antennas are flat but "pointable" to some extent. I assume but don't know for sure that there's at least some kind ...
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2 votes
0 answers
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Studies that identify the best frequencies for transmitting interstellar messages?

We are searching for extraterrestrial communications from other solar systems, and some consider sending them as well. Are there studies attempting to identify which wavelengths are best suited for ...
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What kind of technology is required for Alpha Centauri communication?

Let's assume we already colonised Alpha Centauri. What kind of technology we need in order to send and receive 1kbps? Radio satellite orbiting the sun? How much power, antenna size and solar panel ...
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2 votes
3 answers
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Closest distance at which cubesat (or comparable smallsat) has communicated with the Deep Space Network or any large 10+ meter dish? Cis-lunar ever?

Discussion below Will future deep space optical communications "ground stations" actually be in space, or on the ground? has got me wondering about the improbable situation where a giant ...
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6 votes
3 answers
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How many independent demonstrations of optical communications between ground and space have been successful?

As everybody knows, the pioneering work of The Professor and his serendipitous collaborator Gilligan demonstrated the reality of ground to space optical communications back in 1964. In that case ...
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2 votes
1 answer
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"...extending the Starlink network using longer-range laser comms and relay satellites to reach Mars and Starships in-transit" (Musk & Shotwell)

I have it on good authority that SpaceX's Elon Musk and Gwynne Shotwell: ...have talked about extending the Starlink network using longer-range laser comms and relay satellites to reach Mars and ...
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1 vote
1 answer
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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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2 votes
3 answers
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How would you calculate the maximum bandwidth possible in space?

If you'd take Earth and Mars, and at both their closest and furthest position (ignore the Sun being nearly in-between for a moment), what would be the maximum amount of bandwidth possible between ...
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4 votes
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What's the current state of Venus orbital infrastructure?

As per this Wikipedia article there have been a total of 5 orbiters successfully deployed to Venus: Venera-15 Venera-16 Magellan Venus Express Akatsuki Of which only the Akatsuki seems to be ...
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