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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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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
327 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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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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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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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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2answers
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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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1answer
50 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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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-...
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3answers
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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 ...
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2answers
144 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
150 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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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
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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
257 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
459 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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175 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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1answer
503 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
437 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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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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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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737 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?
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2answers
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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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1answer
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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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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 ...
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3answers
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Why would GPS availability be reduced by high demand (or solar eclipse)?

This Newsweek article states that "GPS...will likely be nonexistent near the eclipse zone" because of all the people going to that area. While it makes sense that cell towers might be overloaded and ...
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2answers
156 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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212 views

How do satellites communicate with a relay satellite?

Although the exact usage of the system is classified, NASA has a system called TDRS which is used by other government agencies for relaying data to ground stations. To maintain communications with a ...
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1answer
201 views

Will there be “Near Space” Ka band allocations for TESS?

update: More information in Phys.org's news item TESS mission to discover new planets moves toward launch, including a video of the telescope array's final assembly. Also see GSFC's TESS page. The ...
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791 views

Why is TESS' high gain antenna made of undulating BLACK fabric rather than metal?

above: from Facebook, then annotated. There is an excellent review of the design of the TESS spacecraft in G. R. Richter et al. Journal of Astronomical Telescopes, ...
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2answers
188 views

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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1answer
186 views

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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1answer
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Real time communications in space

Today we use audio and video communications (using UDP protocol) over IP networks (VoIP) for communicating (Skype, Whatsapp, FB messenger). This works fine on planet Earth (although there are various ...
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Why doesn't thermal radio emission from a DSN “hot dish” completely swamp the benefits of a cold LNA?

The 70 meter DSN dishes are often used to receive the weakest signals, and so their receiver LNAs have cryogenic front-ends in an assembly that also contains a LHe refrigerator and vacuum system. If I ...
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265 views

What are the main sources of radio noise & interference limiting deep space data rates and availability?

Let's call "radio" anything electromagnetic below 300 GHz (1 millimeter), unless there is a compelling reason to do otherwise. The as yet unanswered question How well can Voyager 1 separate Earth ...
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339 views

Faster than light communications in space [closed]

Today communication with different spacecraft is limited to speed-of-light. Around the Earth it is not such a problem, but when you have to work with a spacecraft on the surface of Mars, it becomes an ...
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2answers
751 views

Is it possible for small satellites to orbit in MEO or GEO?

I am researching satellite technology, and in particular I am looking at the rise and implications of smallsat technology. As far as I know, there are currently no satellites beyond LEO that would be ...
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204 views

Characteristics of the modern satelite radio transmitters

I'm trying to find some data concerning current Earth-satellite radio communication systems, namely general characteristics of the equipment currently used on satellites. Specifically, I'm interested ...
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1answer
553 views

Why were the two Quindar tones so close in frequency and not apodized?

This and this answer explain the function of the Quindar_tones within Apollo mission comms. At 2525 and 2475 HZ they are only 50Hz or 2% apart in frequency, and the duration is 250 ms or 0.25 seconds....
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630 views

What purpose serve the audible “bip” on apollo radio communications? [duplicate]

When looking at moonwalk videos, we can hear bips. What are those bips? Why are there bips? Do this bips still exist in nowaday space missions?
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245 views

With the correct antenna and transmitter, could the Sojourner rover be reactivated?

The Sojourner rover was deployed as part of the Mars Pathfinder mission. At the end of the mission, the Sojourner rover was still operable. But the base station that the Mars Pathfinder carried failed....
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3answers
566 views

How much power do missions to other planets use for radio transmissions?

How much power did the voice and data radios have on the Apollo missions? Additionally how much broadcast power is used on data transmissions from the surface of Mars?
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2answers
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Details of Apollo 11 video transmission [duplicate]

NASA has the video of Neil Armstrong on the moon. I'm interesting in the technology how the signal was created and transmitted. There are some details about it in Wikipedia but I'd like to know in-...
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0answers
219 views

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 ...
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3answers
2k views

Could a smartphone really transmit to satellites in a space based internet system?

Space based internet systems, like the one recently proposed by SpaceX and Google, are said to use satellites to communicate directly with end users, without using cellular ground stations. But how ...
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1answer
332 views

Has DSS-43 ever been used in high power mode (>>20 kW) for an emergency situation?

This answer notes that while most Deep Space Network transmitters are 20 kW of power or less, one dish (DSS-43 in Canberra) is equipped with a transmitter capable of 400 kW. As described in 101, 70-m ...
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2answers
240 views

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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2answers
237 views

How is RF spectrum usage coordinated in Mars orbit?

As of 2016 there are multiple operational missions in orbit around Mars. There are possibly more non-operational missions in orbit around Mars, simply because we do not know the final fate of all ...
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1answer
482 views

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 issues as: High relative velocities between the satellites ...
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5answers
395 views

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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2answers
655 views

Would an orbital Deep Space Network be more efficient?

Deep Space Network sites in California, Madrid and Canberra perform an excellent job, for example receiving from Voyager 2 (16+ billion km) at -150 dBm power. However, would it be more advantageous ...