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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26
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3answers
7k 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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2answers
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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/...
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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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1answer
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Why do Teledesic satellites look so weird? What are these structures and where's the satellite bus?

source enlarged and sharpened To my untrained eye I see a weird claw or flower-like antenna array with eight petals in the shape reminiscent of concave dish but not really, that look like they might ...
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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 ...
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2answers
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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: Source The most I can gather from casual NASA articles is along the ...
9
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1answer
203 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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2answers
622 views

What is the pop-up circular disk with spiral pattern in this NASA animation of the Dragonfly helicopter for Titan? Antenna? Kind, band, target?

At 00:36 in the June 2019 NASA video Dragonfly: NASA's New Mission to Explore Saturn's Moon Titan the animation shows it landing then deploying a circular disk with ...
8
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1answer
931 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 though for higher data rates it usually uses UHF to ...
8
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1answer
1k 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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587 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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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 ...
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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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645 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 ...
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718 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, ...
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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 ...
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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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254 views

What are the most common practical design specifications for antenna in space?

I'm writing my thesis on antennas for small satellite applications (cubesats). Apart from the electrical specifications related to the particular application there are also several other "...
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1answer
241 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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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
212 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
332 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
583 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, ...
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1answer
207 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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0answers
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Why are satellite ground station and deep space communications dishes with secondary mirrors usually of Cassegrain design?

The simplest dish antennas have a concave reflector and their feed horns at the primary focus which is "up in the air". That has several inconveniences, it's hard to go up there to do any ...
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2answers
579 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 ...
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1answer
102 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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How does Deep Space Network's DSS-14 transmit radar and receive it at (almost) the same time? (monostatic radar)

@Hobbes' concise yet thorough answer to the question What are monostatic radar observations, and how will Deep Space Network's DSS-13 be used to observe asteroid 1999 WK4's flyby of Earth? tells us ...
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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 ...
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3answers
443 views

Has a probe ever been lost due to folding its antenna, making it unable to communicate?

I remember hearing the story of a probe on the surface of a planet (maybe Venus) that was lost due to an incredible design flaw, and I'm looking for more details. The probe had a dish antenna, and ...
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1answer
62 views

How did Sputnik 1's antennas couple to its body, electrically and mechanically?

Looking at https://www.britannica.com/technology/satellite-communication/Development-of-satellite-communication I found the image of a model of Sputnik 1 below. It shows details of its four rod ...
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1answer
467 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
600 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 ...
4
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1answer
917 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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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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249 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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2answers
217 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
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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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1answer
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Why do AST SpaceMobile satellites have antennas much larger than Starlink, whereas they both aim at providing network coverage anywhere on earth?

I read on cnbc.com (mirror): AST drew the attention of NASA in October, when the U.S. space agency commented on the company’s FCC proposal and said AST’s “extremely large satellites” would create “an ...
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1answer
167 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
139 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 ...
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1answer
153 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
526 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 ...
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1answer
108 views

When the Mars 2020 and Mars Science Laboratory missions were in deep space, what antennas did they have available to communicate with Earth?

This thorough answer to Did the Curiosity and Perseverance rover brains do the driving from Earth to Mars? explains that during deep space flight the rovers' computers were doing most of the thinking ...
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1answer
155 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,...