Questions tagged [radio-communication]

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

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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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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 ...
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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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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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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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Are NASA (and ESA?) deep space spacecraft now generally able to store and forward messages between themselves?

There are discussions under the current answer to Will Curiosity and the Mars 2020 rover be able to communicate with each other via a Mars orbiter? about the feasibility of MRO receiving a message ...
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291 views

Is the utility PREDICT good enough for operational orbital prediction?

I'm looking for a cheap and cheerful, but ultimately working utility or library for tracking a cubesat and predicting link windows. I've been looking at using Orekit. I'm a student, so a lot of its ...
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534 views

Were the Voyager Golden Record / Arecibo message tested for decodability

I was wondering if the microgroove golden records they put on the Voyager spacecraft, or the Arecibo message, along with instruction on how to decode it, were first put to the test with the subjects ...
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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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203 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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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 ...
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442 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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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 ...
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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?
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100 views

Alternatives to the X-Band

is there any other band that can do something similar to what the x-band does? Any that require a smaller antenna and more electrical power?
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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 ...
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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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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 - ...
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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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504 views

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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Are sun outages having more limited impact in some cases?

Sun outages occur when a satellite, usually one in a geostationary orbit, passes between a ground station and the sun. Seen from the point of view of the ground station, the sun looks like it passes ...
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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 ...
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China, UAE and US all sending missions to Mars in 2020 (Summer of L̶o̶v̶e Mars); how far apart are their frequencies?

Gizmodo's Second failure of ExoMars parachute test throws schedule in jeopardy says: ExoMars 2020 is due to launch during a narrow window open between July 25th to August 13th 2020, during which ...
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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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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 ...
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Inter-satellite linking for satellite constellations?

All the existent satellite constellations and the proposed ones talk about inter-plane communications as a very challenging issue due to: High relative velocities between satellites Tracking control ...
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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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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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Curiosity / MRO UHF connection and weak signal modulation

In the case of MRO and Curiosity communications via UHF, an active feedback system was implemented in which Curiosity monitored the quality/SNR of the connection and commanded Curiosity to increase / ...
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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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Are and should satellites use wireless communication internally, rather than cables?

Some applications on Earth replace wires with radio communication, standard stuff like Bluetooth. It saves mass and maybe complexity. Is this done for intra-satellite communication and deep space ...
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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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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 ...
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Why did Sputnik-1 transmit on both 20 and 40 MHz?

Wikipedia's Sputnik 1 and this answer to Why did Sputnik 1 have four antennas? say that Sputnik transmitted at both 20 and 40 MHz. Why two different frequencies? Why so far apart? It's worth noting ...
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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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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 ...
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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 ...
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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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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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Earth-Mars Radio Blackout: Is it possible to define an extended solar radius to solve this as a geometric problem?

Solar atmosphere causes difficulties in communication during opposition (when Mars is almost behind the sun w.r.t. Earth). The question is: is it possible to define an extended radius for the sun, ...
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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,...
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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 ...
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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' ...
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Is the recently discovered VLF-induced radiation barrier in any way important or useful?

There are several popular news articles that refer to this video, who's notes point to the NASA news item NASA's Van Allen Probes Spot Man-Made Barrier Shrouding Earth which points to the ...
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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, ...
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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 ...
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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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What was the modulation used in the Space Shuttle Ku-band comm system?

The Ku-band system consisted of a directional antenna mounted in the orbiter payload bay and provided high BW communication with a ground station. This page: KU-BAND SYSTEM describes the system as ...
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How many total hours had Arecibo transmitted a signal?

Update: Sadly, parts of the dish have collapsed, several cables have snapped, and the Arecibo radio telescope is now decommissioned and demolition has been recommended because it is now too unsafe to ...
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Could multimode (polymer) optical fiber Gigabit Ethernet be a better choice than WiFi inside future satellites?

In this answer the recent question Are and should satellites use wireless communication internally, rather than cables? it is stated that: This is actually an open research area and despite ...