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Questions tagged [radio-communication]

Using radio wavelengths to communicate between multiple spacecraft or between a spacecraft and the Earth.

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228 views

How would the Voyagers finally die if allowed to transmit to the bitter end?

According to this answer and this question the Voyagers will run out of power to "operate a single instrument" in 2025 for Voyager 2 and a little longer for Voyager 1. It is purported to be the end of ...
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1answer
55 views

Are the Voyager spacecrafts' X-band TWTAs currently set to high or low transmit power? How often were they changed?

In this answer I discuss that the Voyager spacecraft can be commanded to use either high or low power to transmit to Earth on X-band. Question: Are the Voyager spacecrafts' X-band Traveling Wave Tube ...
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0answers
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Can I transmit signals from a wristwatch to geostationary orbit?

In comments below this answer to the question Which satellites can hear emergency signals from Scott Kelley's watch? we are (or at least I am) trying to figure out definitively if a wristwatch can ...
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4answers
10k views

Has any spacecraft ever had the ability to directly communicate with civilian air traffic control?

Should such a contingency become necessary, mission control centers have the ability to contact (e.g. by telephone) civilian or military air traffic control centers, even those located in other ...
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3answers
2k views

Why not send Voyager 3 and 4 following up the paths taken by Voyager 1 and 2 to re-transmit signals of later as they fly away from Earth?

Voyager 1 and Voyager 2 spacecrafts are on their journey out of solar system. They collected so much of important data that helped us understand our solar system. As these spacecrafts moving out of ...
3
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2answers
151 views

What is the lowest latency achievable in reliable Earth - Moon communications?

I know that radio waves travel at the speed of light in vacuum so the minimal latency to communicate between Earth and Moon would be about 1.25 second each way. This latency figure will then increase ...
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1answer
91 views

What kind of signal Voyager 1 is sending to us?

I was reading on wiki about Voyager 1 mission and I found very interesting! One thing I did not manage to find: what is the signal Voyager 1 is sending to us? Is it simply a sinewave or something more ...
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1answer
37 views

Data Rates and Radios with Satellites [closed]

I am new to using radios and was wondering why do data rates matter when you use a radio to pull info from somewhere else. Also what does it mean when a satellite sends a wide band signal. Thank you ...
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187 views

Which company provided communication equipment for Apollo missions in which Neil Armstrong was a part?

In July 1969, the Apollo mission transmitted Neil Armstrong’s first steps on the moon to millions around the world. Which famous company provided the entire communication equipment for the project?
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1answer
87 views

What is considered a good SNR for satellites?

When performing a link budget for satellite communications, a key component is defining an acceptable signal-to-noise-ratio in order to obtain the necessary bit-rate. How does one determine what the ...
1
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1answer
155 views

If a MarCO-type CubeSat were in orbit around Bennu, what kind of power would it need to communicate with the Deep Space Network?

This is a follow-up question to: What is the lowest power signal that the DSN can detect? Essentially, I have determined that the asteroid Bennu (ranging from 25 to 350 million kilometers from Earth) ...
2
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1answer
102 views

What is the lowest power signal that the DSN can detect?

It is said that the Deep Space Network can detect low-power signals sent from Voyager in the range of 10^-16 W. I can't seem to find any sources that indicate what the minimum power requirement of a ...
2
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0answers
154 views

why do astronauts in the ISS still use wired microphones?

While I watched the DM-1 hatch opening, I noticed that astronauts use the wired microphone to talk to Huston. It was particularly strange seeing that even because during hatch opening, they were ...
2
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1answer
20 views

What are the trade-offs to use a radio relay orbiter also as a radar science instrument?

Any landed mission could benefit from having an orbiting radio relay satellite to help enhance its data rate to Earth. For polar landers on for example the Moon or Mercury it would be a necessity. For ...
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2answers
103 views

When scientific and engineering data are sent from space probes, are the signals repeated to minimize transmission error?

I would think that this would be the case. In any one transmission there will be a systematic error due to the fundamentals of the transmitter / receiver. Is there also a transient or stochastic error ...
3
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1answer
136 views

How many non-crewed deep-space destinations have had intentional broadcasts of music from Earth?

@Ingolifs's answer to the question What was the last message to Opportunity today (13 Feb '19)? quotes ArsTechnica's Opportunity did not answer NASA’s final call, and it’s now lost to us: Late ...
4
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2answers
148 views

How can one know that Chang'e-4 was in “locked to the Queqiao” from this SDR spectrogram?

Deep space SDR enthusiast and amateur radio operator Edgar Kaiser @df2mz's 28-Dec-2018 tweet says: Chang'e 4 in lunar orbit last night on 8479.77 MHz. The spacecraft seems to be locked to the ...
2
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0answers
48 views

Understanding shape of DSN's 'kinky uplink protocol' keeping frequency in coherent transponder's optimum bandpass?

This tweet by deep space SDR enthusiast and amateur radio operator Edgar Kaiser @df2mz shows a squiggly tone from MRO. Mars Reconnaiscance Orbiter (MRO) X-band downlink. The signal shows this ...
2
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4answers
293 views

Hijacked space data, notable instances of recovering images or other goodies from someone else's space mission?

The original of this GIF was tweeted here and I've reconstructed it because I don't know how to post it here (How to show this particular tweeted (GIF?) in a question? - trouble downloading). These ...
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0answers
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Why is the operating temperature for the Voyagers' receiver noise calculation about 1550K?

In line 10 of Table 5.2 of DESCANSO IV - Voyager Telecommunications it shows a value of the uplink receiver noise spectral density of -166.7 dBm/Hz, which is 196.7 dBW/Hz which is 2.1E-20 Watts/Hz = $...
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2answers
113 views

Did New Horizons use its smaller medium-gain antenna for most/all downlinking of Pluto and Ultima Thule flyby data?

Brian May's New Horizons video (below) was released at about the same time that the New Horizions spacecraft passed 2014 MU69 Ultima Thule and includes a lot of technically meaningful graphics. One ...
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1answer
2k views

What is carrier lock and bit lock?

I'm not sure if this question belongs here or in Amateur Radio, but during the acquisition of signal from New Horizons on New Year's Day, I heard the controllers call out "carrier lock", "symbol lock",...
3
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1answer
259 views

From whence (what ground stations) do all the world's space agencies receive signals from their missions?

The ISRO web page Ground Segment says: SRO Telemetry Tracking and Command Network (ISTRAC) will be providing support of the TTC ground stations, communications network between ground stations and ...
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0answers
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Are Hayabusa-2's high gain antenna disks electrically point-able?

Writing this answer I realized that Hayabusa-2 has two very similar looking circular flat disks that serve as it's high gain antennas. One is dedicated to X-band (7-8 GHz) and the other to Ka-band (32 ...
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4answers
7k views

Is Quantum Entanglement technology possible for interplanetary communication in future to achieve low real-time latency?

There is a small debate over the comment session in NASA Lands InSight on Mars video uploaded by JPL. The 1 minute and a half video is about the essential part of InSight's EDL event cropped out from ...
13
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1answer
201 views

Does Mars Reconnaissance Orbiter require “reprogramming” when handling communications for newer spacecraft or landers?

While I was going through the question What happens to Insight's parachute? I learned of the role of the Mars Reconnaissance Orbiter to provide reliable communication between other Mars spacecraft and/...
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1answer
210 views

Power and frequency units used in Deep Space Network XML data?

NASA's Deep Space Network activity can be viewed conveniently at https://eyes.nasa.gov/dsn/dsn.html but if you would like data in a more raw XML form, it can be accessed as described in this answer ...
2
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1answer
66 views

Function and nature of the RHC/LCH pair of cables to New Horizons's dish antenna secondary mirror?

Spaceflight 101's New Horizons Spacecraft Overview is full of interesting information and shows this RF Comm System Block Diagram. The thin (red) lines to the dish antenna area are coaxial cables and ...
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1answer
53 views

How will “InSight's onboard communications gear perform a radio-science experiment to shed further light on Mars' innards?” (Space.com)

The Space.com article How NASA Mars Lander's 'Steampunk' Claw Will Work (Video) says: InSight's mission aims to provide a detailed look at Mars' interior structure and composition. The lander ...
2
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1answer
483 views

Is two-way communication really required to use BeiDou GNSS?

The BBC's How China's GPS 'rival' Beidou is plotting to go global mentions a scenario where end-users can send signals to other Earth locations using BeiDou and later says: But despite its ...
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3answers
347 views

Which satellites can hear emergency signals from Scott Kelley's watch?

In this July 2018 tweet by Cdr. Scott Kelley, with the north face of Mt. Everest over his shoulder, he mentions his "Emergency" watch. I've searched and then found the Hodinkee.com article Hands-On: ...
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1answer
143 views

How does this antenna work, with both a feed horn and hyperbolic secondary in front of the dish?

Scrolling through the Roscosmos twitter feed I saw this image of a dish antenna in a recent tweet. Google translate shows that the post says: Новый измерительный пункт будет построен на Сахалине ...
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1answer
85 views

Which is stronger per Hz, radio signals from a Mars spacecraft, or Mars' blackbody radiation?

It just occurred to me that while Mars is cold from a human's perspective, from a radio engineer's perspective it's still kind-of hot. When even the largest DSN antennas are pointed at Mars to ...
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3answers
412 views

Why have four parabolas on a ground-side array instead of just a single large one

An article on RT: Russia to stop ferrying US astronauts to ISS from April 2019, is accompanied by a photo of a ground-side radio array consisting of four separate parabolas merged into one pointable ...
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3answers
418 views

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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1answer
56 views

Is it practical for HF skywave propagation to be utilized for space exploration robot telecommand when outside of microwave/mm wave range?

Is it practical for HF skywave propagation to be utilized for space exploration robot telecommand when outside of microwave/mm wave range? Currently it appears that only the C band and UHF is used in ...
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1answer
241 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-...
55
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3answers
14k views

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 ...
6
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2answers
172 views

Feasibility of Interstellar Probe Communication

So, I understand that to transmit information across interstellar distances, you need to use a lot of power (or less bandwidth?), something for example a small space probe wouldn't exactly have. If we ...
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1answer
163 views

The appearance of TESS' dish seems to be evolving, what will be the final configuration?

The question Why is TESS' high gain antenna made of undulating BLACK fabric rather than metal? has had three bounties, and is probably the recipient of this sites longest answer. My personal pet ...
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1answer
111 views

Juno RF power output

What is the RF Power Output from Juno into its Parabolic dish, and the RF radiated out from the dish and the eventual power received say at the dish in Canberra which obviously then would need to be ...
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3answers
2k views

Do satellite uplink/downlink signals spread or leak into space?

Satellite communication generally involves three types of nodes: the ground station (also known as teleport), the satellite in geosynchronous orbit, and the satellite receiver/transceiver. I am ...
3
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1answer
401 views

Have deep-space spacecraft always used some form of spread-spectrum for data downlink?

tl;dr: Question: Have deep-space spacecraft always use some form of spread-spectrum for data downlink? note: I'm looking for some insight into why, and any possible exceptions, not just a "yes" or "...
2
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1answer
537 views

Is there really a radio on Elon Musk's solar-orbiting Tesla Roadster? Can we communicate with it? [closed]

Various media have reported that there is a radio on Elon Musk's Tesla Roadster, now in orbit around the Sun, and that this radio is playing music (for example: BBC reporting that David Bowie's ...
3
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1answer
265 views

How does the Satellite Networked Open Ground Station operate? How is it used?

SatNOGS, the Satellite Networked Open Ground Station (mentioned in this answer) appears to be a distribution of independently maintained amateur DIY satellite receiving ground stations, linked by a ...
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2answers
2k views

How to calculate data rate of Voyager 1?

I've read the following passage in the answer to the Quora question How can Voyager send a signal strong enough for us to receive, in spite of its enormous distance from us? And how can it have the ...
5
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1answer
573 views

Why such a large observed doppler shift from Apollo 17 orbiting the moon?

Following the links in this comment by @Uwe I've found some interesting sources of information on Ham (amateur) radio operators trying to listen in on Apollo transmissions. One of them is Sven Grahn's ...
2
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0answers
124 views

Satellite Intra link [closed]

I read there are sometimes intra-satellite links. Is it already used or just a project in the future ? How is is used and why ? and for what services ? thanks david thanks for interesting answers. ...
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2answers
394 views

What is the highest non-optical frequency used or tested for use in deep space communication?

For dish antennas used to transmit a signal over large distances, the on-axis gain scales as $D^2/ \lambda^2$ or $D^2 f^2 / c^2$ where $\lambda$ and $f$ are the wavelength or frequency and $c$ is the ...
2
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2answers
1k views

Would adding satellites between Earth and Mars improve communications latency?

Would adding satellites along the path from Earth to Mars decrease the amount of time it takes to send and receive messages between them?