Questions tagged [radio-communication]
Using radio wavelengths to communicate between multiple spacecraft or between a spacecraft and the Earth.
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What was the transmitting power of the Apollo astronauts' PLSS VHF radio transmitters?
I'm assuming many of you are familiar with Larry Baysinger. A radio amateur who independently detected and recorded the transmissions from the Apollo 11 EVA using a homemade antenna.
Larry Baysinger ...
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1answer
124 views
What “gap” could have caused the Starliner instructions to be delayed?
The Starliner launch didn't go as planned today
After being released by the rocket, Starliner was supposed to use its Orbital Maneuvering and Attitude Control engines to provide the thrust needed ...
2
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1answer
72 views
Possible interference in RF spectrum due to space-based internet
Multiple Commercial Operators plan to use satellite megaconstellations for providing internet coverage in near future.
Is there a possibility of interference between RF spectrum already in use for ...
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Satellite Megaconstellations RF Spectrum usage for free(?)
As per my understanding, for terrestrial usage RF spectrum is auctioned by the governments before telecom operators can avail it for commercial purpose. Seems like a logical way to utilise limited ...
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Satellite Launch Aprroval: what is the role of ITU, FCC, and other international standards / regulators?
Seeking confirmation for the following assumption:
Satellites used for non-communication applications (military surveillance, weather monitoring etc.) are launched without specific prior approval from ...
3
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1answer
88 views
Which radio communication protocol will Artemis voice communications likely use?
For want of a better term, is it possible crews will use 'non-digitally modulated' radio to communicate with earth?
Apollo missions had very effective communication, with a ~2.5 second 'round trip' ...
4
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1answer
141 views
What radio frequencies were used by the Soviet space program circa 1961? (“Lost Cosmonaut” recording)
The recent Joe Scott video The Mysterious "Lost Cosmonaut" Recording | Random Thursday describes radio recording said to have been made by the Judica Cordiglia brothers from Italy in the early 1960's.
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86 views
Impact of having two antennas on link budget calculations
I'm working on link budget of a cubesat mission that needs to have two dipole antennas that are perpendicular to each other. I want to know if having two antennas affect the link budget? losses, and ...
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How many total hours has Arecibo transmitted a signal?
Although it is technically a radio telescope for astronomy and radar ranging, the Arecibo Observatory has been used for Messaging for Extra-Terrestrial Intelligence (meti). How many total hours has ...
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What's the “thump” I hear listening to Apollo 11 playback?
I've been listening to live playback of the Apollo 11 mission at https://apolloinrealtime.org/11/
Besides the expected static and hums, from time-to-time I hear a "thump", sometimes one, sometimes ...
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3answers
183 views
How large of an antenna would you need to connect to the ISS's WiFi network from Earth?
Supposing I wanted to connect to the ISS's WiFi network from the ground, how large of an antenna would I need to do so, and what kind? Would they need to increase the power on their end or use a ...
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1answer
606 views
What Soviet signals (if any) attempted to scramble communication and sabotage Apollo missions?
The NPR.org news item and audio podcast JoAnn Morgan: The Only Woman In The Firing Room During Apollo 11 features an excellent interview with JoAnn Morgan and other KSC personal.
It's a short but ...
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1answer
63 views
What kind of transmitters and antennas do the Lightsail-2 ground stations use?
The cubesat Lightsail-2 has been deployed and has communicated with ground stations. See The Planetary Society's LightSail 2 Healthy as Mission Team Continues Spacecraft Checkouts, where it says:
...
22
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1answer
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Was “I have the farts, again” broadcast from the Moon to the whole world?
The BBC News article Apollo in 50 numbers: Medicine and health says:
When Apollo 16 commander John Young walked on the Moon, he shared his feelings on the new diet with his companion Charlie Duke. ...
2
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1answer
116 views
How does an onboard atomic clock help interplanetary navigation?
On 2019 June 22, JPL will launch and test the accuracy of an onboard atomic clock. Its FAQ says that it will improve interplanetary navigation because for the ship to determine its position, instead ...
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1answer
73 views
IRIS Transceiver for LEO Missions?
My professor really wants to know if the IRIS transceiver, which flew on MarCo, will be used in LEO. In fact so much that he doesn't accept "no" for an answer. I have searched for an example but found ...
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1answer
685 views
Why does NASA use higher frequencies even though they have worse Free Space Path Loss (FSPL)?
Looking at the Formula for FSPL we see that it increases with Frequency.
Why is X-Band used for Deep Space Communications instead of lower bands like S-Band? Is it a question of data-rates? Is the ...
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2answers
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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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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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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
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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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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
394 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
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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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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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378 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
712 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 ...
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1answer
175 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
131 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
175 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
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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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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 ...
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1answer
143 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
176 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
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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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4answers
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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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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
239 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",...
3
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1answer
322 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
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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
216 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
248 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
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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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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
699 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
439 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
203 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
94 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
542 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 ...
