Questions tagged [antenna]

Questions about devices which collect and couple electromagnetic signals (communications, radar or other electromagnetic measurements) directly between free space, and conductors (e.g. waveguides or other transmission lines).

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25
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2answers
3k views

What is the function of this (apparently) fixed dish on the ISS?

I saw this image in Popular Science, one of the example photos from the book by astronaut/photographer/astrophotographer(?) Donald Pettit. It's beautiful and impressive not only from a color/...
24
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2answers
6k views

What is the purpose of the rotating dish antenna on the ISS

I just saw some footage of the ISS in which a dish antenna could be seen, constantly rotating. The dish looked more-or-less parabolic, meaning that it is presumably sending/receiving along a fairly ...
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How do these cubesats' whip antennas work?

This answer has identified the three 1U cubesats shown in the question, and links to Engineers Rule's Maya-1: The Philippines’ First CubeSat along with the video Animation of MAYA-1, The Philippines' ...
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Did NASA's Borg Collective-designed antennas work? Have similar designs ever been used in spacecraft beyond testing?

This interesting answer to the question Do antenna farms on spacecraft make any sense or are they purely aesthetic? in Worldbuilding SE links to the NASA Ames page 'Borg' Computer Collective Designs ...
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Why did Sputnik 1 have four antennas?

Sputnik was only launched a few hundred kilometers above Earth, and transmitted only a simple beeping signal. What was the purpose of having four antennas? Wouldn't one be powerful enough?
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What is the large circular device with a dozen concentric circles on Sentinel 3B?

The Spaceflight Now article Photos: Sentinel 3B satellite prepared for launch from Plesetsk Cosmodrome has of course lots of photos. One of them shows a dish antenna covered with shiny, metallized ...
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What antenna is this in an Apollo 15 LM photo?

The video Apollo 15 landing from PDI to Touchdown (found in Why did the Apollo 15 LM violently shake & raise dust after the contact probes touched the lunar surface?) seems to pan across a still ...
9
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1answer
183 views

When did deep-space probes start getting wrapped in germanium-coated film?

The NASA video Juno Engineering: Precision Matters shows the Juno spacecraft on what look like it might be a spin balance table after about 02:50 and there one can ...
8
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1answer
929 views

Radiation pattern and signal strength of navigation satellite antennas

Where can I find the actual radiation pattern and signal strength of transmitting antennas used by GNSS navigation satellites/constellations (GPS, GLONASS, IRNSS, etc)?
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1answer
945 views

When is a phased array antenna not a phased array?

This question is inspired by an answer to this question, where it is stated that: The real power of phased arrays is their ability to be steered electronically. This set me wondering about the ...
7
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637 views

What are these antenna-like structures seen in Oleg Artemyev twitter video?

Russian Cosmonaut Oleg Artemyev's Sept 3, 2018 tweet has a narrated video of Earth from the ISS, at the time over the Nile river. The video is also in YouTube (below). At the bottom of the screen, ...
7
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329 views

Why do these satellite antennas look so weird? (strangely shaped with little white dots…)

The NASA Spaceflight article Arianespace press onward with dual-passenger Ariane 5 launch shows a photo of Intelsat 39 during testing. The dish reflectors are strangely shaped: rather than being ...
7
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1answer
403 views

How do commercial broadcast satellites in GEO produce such carefully shaped signal footprints?

SES-10 will be launched in a few days on Space-X's first commercial launch using a recycled rocket. Screenshots from the three links (Brazil, Central America, South America) on Satbeams page for SES-...
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1answer
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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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871 views

What is this spinning object seen on a spacecraft above the ISS?

In the YouTube Trailer for the PBS program A Year in Space at 00:56 a small spinning object can be seen, attached to a spacecraft well above the ISS. I think the ...
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How did this structure fit into the Shuttle and then expand to 28 meters?

In this answer I read about the Inflatable Antenna Experiment that flew with STS-77. According to this article: Packed into the Spartan, the IAE weighed only 132 pounds; on deployment (inflation), ...
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How are phased array antennas used in spaceflight? Benefits and limitations

It would seem to me that a phased array antenna would be great for spacecrafts since it removes the need to turn the entire spacecraft around in order to point the radio dish towards Earth. Many ...
6
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2answers
322 views

How does the pattern on the MarCo cubesat's antenna boost data-transmission?

I was looking at a few posts that uhoh had made about the MarCo cubesat. One of the pictures was the one that I've posted below: The most I can gather from casual NASA articles is along the lines of: ...
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1answer
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Could the Voyager spacecraft be spin-stabilized to keep their high gain antennas pointing towards the Sun (and therefore Earth)?

A suggestion has been made that the Voyagers may run out of propellant and so may not be able to maintain pointing near the Earth for communications. According to @BowlOfRed's answer: Although the ...
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117 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 ...
5
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1answer
319 views

Deep space craft antenna aiming

In order to aim an antenna at Earth, how do unmanned spacecraft find their own orientation (xyz position in space, what direction it is flying and which direction the antenna is pointing)? Are they ...
5
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1answer
187 views

Help understanding how these components of a Honeysuckle Creek dish antenna work

@Fred's comment links to the Curious Droid video How Australia Helped Save Apollo 13 and a little after 02:15 and 03:00 it shows ...
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1answer
506 views

How does Curiosity know how to point and move it's high gain antenna in real time?

The Curiosity rover has a compact X-band high-gain antenna (HGA) that allows for low data rate communication directly with Earth, but is used mostly for higher data rates to spacecraft orbiting Mars, ...
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1answer
523 views

How is GAIA's phased array configured, mechanically and electrically?

GAIA is an amazing pair of space telescopes that share a single Gigapixel CCD array, with a complex optical system capable of repeated, extremely precise position, brightness, parallax, proper motion, ...
5
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1answer
163 views

What happened to the plan to build a DSN antenna array?

More than ten years ago there were plans to build large antenna arrays for DSN, about 400 antennas of 12m diameter. See these NASA papers 1, 2, 3, 4. What happened to these plans?
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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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541 views

Can't we use laser transmitters instead of large radio dishes on deep space probes?

Isn't it possible to use a laser as an "antenna" that transmits data? This would save quite a lot of mass since you don't need a large dish. The only problem I can think of is how would you modulate ...
4
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1answer
78 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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1answer
265 views

Why do GEO satellites need different types of antenna?

Why do GEO satellites like the one shown in the picture below need different types of antenna? Is there a reference library or website where we can get more information on different antenna types, ...
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1answer
870 views

How does SpaceX Falcon Heavy Starman live feed transmitter work?

I'm curious to find out answers to the following questions: Where is the antenna for the live feed transmitter of starman located in the payload? How is the transmitter being powered? Related to 2nd ...
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3answers
812 views

What is the largest antenna deployed in space?

@Tristan's answer says: The satellites are classified, so details are speculative, but it is believed that the Magnum/Orion and Mentor SIGINT satellites have parabolic antennae around 100 m in ...
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2answers
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How to design a ground antenna for sending & receiving from a satellite?

Let's suppose there is a wifi router or a cell phone or similar transmitter in an orbit of 3000 km. How could one make a dish antenna to connect and receive the signal from that wifi router or cell ...
3
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2answers
127 views

How exactly were the signals from quad dishes of Apollo Deep Space High-Gain Antenna or Russian B-529 processed for local control of tracking?

The images below (and their sources) show the quad dishes of the Apollo Deep Space High-Gain Antenna and the Russian B529 ground station tracking antenna. From NASA Technical Note TN D-6723 Apollo ...
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1answer
342 views

How were the 100+ antennas around Telstar 1 and 2 configured?

Telstar 1 and 2 demonstrated routing of telephone, television and other communications types between continents. The Smithsonian Air and Space Museum pages below contain images of the satellites. ...
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3answers
197 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 ...
3
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1answer
154 views

Exchange diameter for power in parabolic antenna

If I want to reduce the diameter of a satellite dish, how much power should I add to the transmitter? how is this formula? As I have already been informed a little in this other question I asked: X-...
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3answers
98 views

Which deep space spacecraft had main dish antennas that were perforated or made from mesh?

A long time ago I was considering asking why the dish antennas on some deep-space probes were perforated metal or mesh (presumably to save weight), while others were solid. I'm trying to finally ...
3
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1answer
125 views

Need help identifying this (likely to be) phased array antenna used to track launches

I need help identifying the (what I believe to be) flat (and possibly phased) array antenna shown next to the tracking telescope in this photo, which can be found both here and here where the ...
3
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1answer
374 views

What were those motorized human-piloted platforms with helical antennas called (tracking launches)?

This interesting question got me started. I have these vignettes in my Apollo-era memory of antenna systems that tracked launches for telemetry. They had maybe four end-fire helical antennas pointing ...
3
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1answer
85 views

How do I calculate what antenna I need for my cubesat?

If I want to make a communication satellite, like MarCO, what formulas do I need to calculate the perfect antenna? Is there a difference between the X-Band and the classic UHF? If the cubesat is ...
3
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1answer
258 views

How do you calculate the lat and lon of a point on the earth using azimuth and elevation seen from a geostationary satellite?

I am given the longitude of a geostationary satellite and a pointing vector from the satellite in the form of azimuth and elevation angles looking from the satellite towards the earth (where zero ...
3
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1answer
214 views

How does this large, flat antenna made from overlapping circles at Australia's Carnarvon Space Tracking Center work?

@Fred's comment links to the Australian Broadcasting Corporation's How the Apollo 11 Moon landing was achieved with the vital help of Carnarvon Tracking Station which links to their Carnarvon space ...
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0answers
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How would the antenna on a spacecraft in GEO be provided an electrical ground?

I would like to understand better what specifications or guidelines address the electrical grounding/Earthing a parabolic reflector Antenna in GEO to minimize the potential difference with respect to ...
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What is the Telescope Invariant Point?

I am working on an implementation of an SLR tool. At some points of the documentation of the CRD format the term telescope invariant point shows up. Apparently it's a point on an ILRS antenna system. ...
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3answers
257 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
115 views

What's the largest area dish antenna sent beyond the Earth-Moon system?

In the same vein as the question What's the largest aperture telescope sent beyond the Earth-Moon system?, I'd like to ask, what's the largest area antenna dish sent beyond the Earth-Moon system? If ...
2
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1answer
108 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
737 views

What is Canted Turnstile Antenna System? What it its Applications?

There are not many sources I can read to know about this kind of Antenna and its Applications
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1answer
137 views

How does this fast-slewing dish track moving spacecraft?

Elon Musk's recent tweet shows a video clip of a modest-sized dish on fairly fast-slewing mount located: At SpaceX Boca Chica launch site in Texas In the question Why is the reflector on this ...
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1answer
337 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 ...