Questions tagged [radio-communication]
Using radio wavelengths to communicate between multiple spacecraft or between a spacecraft and the Earth.
184
questions
4
votes
0
answers
121
views
Polarization mismatch between a LEO satellite and ground terminal
Cross-polarization loss between a circularly polarized antenna and vertical or horizontal polarized antenna is known to be -3dB. This is one of the reasons why Circular Polarized antennas are ...
- 153
3
votes
0
answers
103
views
What does it mean when they say "switch to 32K " during the Phoenix Mars entry
In the Phoenix Mars entry video
they keep saying "Odyssey switching to 32k", "Stop of Odyssey unintelligible Data and switch to 32k",and "We ...
- 233
7
votes
5
answers
3k
views
What is the maximum distance between two satellites orbiting at 400 km that would still allow them to communicate with each other using radio waves?
All satellites have the same inclination.
At an altitude of 400 km, the circumference of their orbit is $2\pi \cdot (6371+400) = 42\ 543$ km.
If, for example, you have only 2 satellites separated by ...
13
votes
1
answer
1k
views
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 ...
- 147k
4
votes
1
answer
164
views
Radio Telescope / DSN Node in L4 and/or L5
Deploying really big radio dishes in space seems to be possible and "frequently" done with SIGINT satellites in geosynchronous orbit (like the assumed specs of the Orion satellite class). ...
- 2,606
3
votes
1
answer
413
views
How does the signal strength from the Voyager probe change with distance?
How does the signal strength from the Voyager probe change with distance? Where I can find this data?
- 163
15
votes
1
answer
712
views
Would it be possible to receive the transmissions from JWST as an amateur?
Would it be possible to receive the transmissions from JWST (James Webb Space Telescope) as an amateur, building your own antenna?
Would the transmissions be encrypted?
One source cites it using: S-...
- 101
4
votes
0
answers
111
views
Are circuit diagrams available for the Voyager spacecraft telecommunications systems?
I'm particularly curious about the coherent transponder mode where the outgoing transmitted signal is phase-locked to the incoming received signal (prompted by @uhoh's recent question). This is a mode ...
- 3,674
4
votes
1
answer
66
views
Fjeldbo, Kliore, & Eshleman 1971 Fig. 22 planetary atmosphere index of refraction increasing with altitude; physics insight or convenient abstraction?
this answer to Is it possible for a spacecraft to communicate with Earth when a planet is in the way? suggesting that atmospheric refraction could be used to get at least some kind of signal around a ...
- 147k
5
votes
2
answers
95
views
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 ...
- 905
1
vote
1
answer
138
views
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 ...
- 375
2
votes
1
answer
104
views
What antennas does JAXA use to communicate with its deep space spacecraft? Does it have a deep space network of its own?
@BrendanLuke's answer to Are there currently any spacecraft in orbit around Venus that might (or might not) be at risk of meteoric dust from comet Leonard C/2021 A? alludes to the exciting story of ...
- 147k
3
votes
1
answer
88
views
Radio antenna used to communicate with the Telstar 1 satellite in 1962
Related to Why was Telstar 1 put in a 952 x 5933, 2.6 hour 44.8° MEO orbit?.
The satellite ground station at Andover, Maine, that was used to communicate with the Telstar 1 satellite was a horn ...
- 11.4k
1
vote
0
answers
84
views
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 ...
- 19
13
votes
1
answer
855
views
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 ...
- 3,608
2
votes
2
answers
317
views
Why does the Crew Dragon seem to rely primarily on a low bandwidth downlink for voice communications?
What are the particular reasons that the Dragon Capsule is not communicating via Starlink, or that it seems that the audio and video downlinks from the Dragon Capsule are on separate streams?
- 291
8
votes
2
answers
587
views
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 ...
- 91
7
votes
1
answer
127
views
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 ...
- 373
2
votes
0
answers
112
views
What interstellar data rates are feasible? [closed]
Preamble: Mankind has colonized the galaxy with self replicating machines which build transceivers when they arrive at a new star system which transmit and receive uploaded human minds and AI between ...
- 411
18
votes
1
answer
3k
views
What happened to Voyager 2's tracking loop capacitor? How did it get damaged? What is it for? What's a tracking loop anyway?
On 23-Aug-2021 Voyager 2 tweeted:
DSN antenna DSS-43 at @CanberraDSN is starting a 300 min listen to hear the echo of a command tone sent up to me 35 hours ago. This will define the "Best Lock ...
- 147k
1
vote
1
answer
145
views
Just how raw is the rawest signal data that the Deep Space Network routinely records for safety reasons?
When we watch videos of some Spacecraft landing there's a big screen with real-time plots of the data coming from the Deep Space Network's antennas.
Presumably the information is recorded in fairly ...
- 147k
1
vote
1
answer
108
views
How were Soviet/Russian aircraft used to track and/or communicate with spacecraft?
Russian Space Web's Russian ground control and tracking network mentions
A Soviet Iluyshin-18 aircraft configured to maintain communications with spacecraft.
in the sidebar and includes the small ...
- 147k
1
vote
2
answers
232
views
How can SpaceX receive data from Starship during re-entry communications blackout
Surviving re-entry will be one of the initial critical aspects of the Starship development program.
If there are locations on the vessel where the heat-shield fails, leading to its destruction how ...
- 664
1
vote
1
answer
84
views
How does Quantum change it's antenna's shape? (Flagship UK telecommunications satellite just launched)
The BBC's Quantum: Flagship UK telecommunications satellite launches includes the following:
A quarter of the world's big telecoms spacecraft are manufactured in Britain, and the new Quantum platform ...
- 147k
0
votes
1
answer
163
views
Why is the Fermi paradox' assumptions so strong? Do they even need to be?
The Fermi paradox first states that it is highly likely that intelligent lives have existed on planets long ago. As in, not just on one planet, but on billions of planets.
Then the paradox goes on and ...
- 11
2
votes
0
answers
166
views
Is or was STARGATE really being used for SpaceX launches at Boca Chica or otherwise?
The 2015 answer to For SpaceX's Texas launch site, what kind of range radar/tracking will they have? links to The Spacecraft Tracking and Astronomical Research into Giga-hertz Astrophysical Transient ...
- 147k
6
votes
0
answers
97
views
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 ...
- 61
7
votes
1
answer
176
views
Will there be a command moratorium for Mars spacecraft again in 2021?
About every two years, Earth and Mars are on opposite sides of the Sun (a Mars-solar conjunction). Plasma expelled from the Sun can interfere with radio transmissions between Mars spacecraft and the ...
- 46.9k
4
votes
1
answer
350
views
Why are deep space "beacons" usually UHF, so low (in freq) that DSN can't hear them? And how unusual is it for a Mars lander to have an X-band beacon?
This answer to Is there independent evidence that China landed a robot on Mars in May 2021? and an extensive comment below it indicate that the Zhurong Mars lander had an X-band beacon, information ...
- 147k
3
votes
1
answer
420
views
How would I determine the power usage for a X-Band High Gain Antenna?
Currently I have that for a X-Band High Gain Antenna functioning at 8 Ghz, diameter of 3 meters, and a power transmission of 13.1dBW (20 watts) at a distance of about 8.5 AU has a Gain of 52.44 dBi, ...
1
vote
1
answer
53
views
Are these good specifications for a X-Band High Gain Antenna?
Currently, I have that for a X-Band High Gain Antenna functioning at 8Ghz, diameter of 3 meters, and a power transmission of 13.1dBW(20Watts) at a distance of about 8.5AU has a Gain of 52.44dBi, free ...
5
votes
2
answers
145
views
Have solid dish antennas on deep space spacecraft (as opposed to meshes) ever provided any other helpful function? As meteor shields perhaps?
This answer to Which deep space spacecraft had main dish antennas that were perforated or made from mesh? tells the tale:
Galileo's troubled high gain antenna was made from "a gold-plated ...
- 147k
6
votes
2
answers
530
views
Does the Ingenuity helicopter on Mars have a radio call sign?
This Deep Space Network page lists some of the call signs of various robotic spacecraft. For example, Curiosity is MSL, and Perseverance is ...
- 46.9k
5
votes
1
answer
133
views
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 ...
- 375
4
votes
2
answers
245
views
What does it take to upgrade a radio antenna to receive from the surface of Mars?
All the discussion about receiving transmissions from Mars rovers got me thinking, what determines the capability of a radio antenna, and what goes into adding the capability of listening to a Mars ...
- 7,916
8
votes
0
answers
766
views
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 ...
- 147k
3
votes
0
answers
192
views
What was the most intense beam ever sent from Earth?
By a freak coincidence sensors on a passing alien ship a hundred light years away had picked up a faint artificial blip from Earth, thereby discovering our inhabited planet. But which blip was it?
...
- 147k
1
vote
2
answers
170
views
Why are minimum three artificial satellites required for radio-communication all around the Earth?
Artificial satellites orbiting the Earth have important applications for radio-communication around it.
To avoid the blockage of radio-communication around the Earth, multiple satellites can be ...
0
votes
1
answer
185
views
How long did the plasma blackouts of Perseverance's signals to MRO and direct-to-Earth last during its seven minutes of terror?
Congratulations to NASA JPL and the Perseverance Team and everyone else who participated and contributed in some way!
Watching the live feed of the EDL seven minutes of terror I heard there was a ...
- 147k
3
votes
1
answer
60
views
Does SPICE function gftfov account for occultations?
I need to determine when an antenna on a spacecraft can see a ground station on Earth at particular epochs. I have generated all the necessary SPICE kernels necessary as well as using the NASA ...
- 63
3
votes
1
answer
290
views
Does the Juno spacecraft have an "open signal, by design"?
The click-bate title'd Space News article China quietly used NASA’s Jupiter probe to test its deep space network contains the quoted material below.
Everybody listens to everybody else's spacecraft's ...
- 147k
3
votes
1
answer
207
views
What is a Beam Waveguide dish and why do deep space communications stations use them?
NASA Spaceflight.com's Deep Space Network upgrades and new antennas increase vital communication capabilities says:
NASA’s Deep Space Network, commonly referred to as the DSN, has welcomed a new dish,...
- 147k
4
votes
1
answer
289
views
First Ham Radio contact from space; what frequency, what kind of antenna, and how did they route the coax out the window?
From Phys.org's Earthlings and astronauts chat away, via ham radio:
NASA astronaut Doug Wheelock was just a few weeks into his six-month mission at the space station when feelings of isolation began ...
- 147k
4
votes
1
answer
134
views
When our Moon is hiding Mars, is it possible to create a radio communication between Earth and Mars?
According to this link
Mars is hiding behind the Moon ... It’s a twice-a-year occultation; like the eclipse
When such situations happen, can we communicate with the Mars rovers, and in the future - ...
- 515
3
votes
2
answers
416
views
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, ...
- 147k
27
votes
2
answers
1k
views
How will the closure of the Arecibo dish impact deep space communications?
Earlier today, the U.S. National Science Foundation announced that it is decommissioning the Arecibo radio telescope. The 305 meter dish is famous for the 1974 message for extra-terrestrial ...
- 46.9k
2
votes
2
answers
434
views
What is the bandwidth (in hertz) of the Voyager 2 radio receiver?
Does anybody know the bandwidth of the Voyager 2 radio receiver's front-end?
I know that the current data rate of the receiver is of order tens of bits per second, and I have one estimate of 18 Hz. ...
- 91
5
votes
0
answers
138
views
When, if ever, did deep space probes start using encryption?
What, if any, mechanisms prevent unauthorized commands? Asks what measures are taken for spacecraft, although the answer doesn't go much farther than pointing to the What would one need to do in order ...
3
votes
1
answer
81
views
Problems receiving Iridium messages during the middle of the 'day' in the far North
I have some scientific instruments using Iridium modems for communication active at around or higher than 82°N. At the time of writing this message, we are in middle of August, i.e. the polar day ...
- 131
5
votes
1
answer
175
views
Is GNU Radio being used for any Deep Space Missions in development?
GNU Radio is an open source collection of code and tools to build various radio elements for a "Software Defined Radio" or a radio implemented with the help of an FPGA that is programmed to ...
- 2,254