Questions tagged [radio-communication]
Using radio wavelengths to communicate between multiple spacecraft or between a spacecraft and the Earth.
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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 ...
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2answers
2k 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
185 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
61 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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3answers
515 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
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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 ...
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1answer
202 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) ...
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1answer
187 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 ...
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0answers
398 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
22 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
123 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
163 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 ...
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2answers
216 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 ...
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0answers
56 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 ...
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5answers
723 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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2answers
444 views
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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3answers
283 views
Did New Horizons use its smaller medium-gain antenna for most/all downlinking of Pluto and Arrokoth flyby data?
Brian May's New Horizons video (below) was released at about the same time that the New Horizons spacecraft passed 2014 MU69 Arrokoth and includes a lot of technically meaningful graphics.
One item ...
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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",...
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2answers
427 views
From whence (what ground stations) do the world's major 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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4answers
8k 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 ...
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1answer
231 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
304 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
...
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1answer
122 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
59 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 ...
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1answer
941 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
501 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 ...
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1answer
307 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 для ...
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1answer
115 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
676 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
688 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
62 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
335 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-...
54
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3answers
16k 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
197 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
199 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
251 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 ...
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1answer
497 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 "...
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1answer
745 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 ...
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1answer
410 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
4k 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 ...
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1answer
853 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 ...
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0answers
168 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
614 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 ...
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2answers
2k 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?
3
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2answers
442 views
How does this strangely-shaped horn at Honeysuckle Creek Tracking Station work?
After reading the BBC article Australia to create national space agency and clicking around to identify the dish antenna shown in the photo in the article, I came across an image of an interesting ...
3
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1answer
425 views
Why are there so many waveguide feeds (?) near the focus of Cassini's dish antenna?
Cassini has quite a complex Radio Science Subsystem. Accorting to that article (and confirmed in Wikipedia):
Cassini is the only deep space mission to transmit to Earth at three radio wavelengths (...
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4answers
2k views
How many stations could one hear with an AM/FM radio in front of the ISS' cupola window?
Propagation of AM and FM radio signals up into the sky would behave differently than propagation along the surface of the Earth.
As a Gedankenexperiment, if you were on the ISS and had an AM/FM radio ...
