Questions tagged [communication-satellite]

Questions about satellites designed to aid in communications, such as phone, TV and Internet satellites.

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LEO Satellite Service / Coverage Time Calculation for a Ground User

I want to determine the time interval during which a ground user is in the coverage of a particular LEO satellite. I only have knowledge of the user's geographical location and the satellite's TLE (...
Black Dagger's user avatar
1 vote
1 answer
239 views

What network does the Chandra X-ray Observatory satellite use to communicate with Earth while staying in its orbit?

From a NASA fun facts website How do satellites communicate?: How do satellites communicate? Satellites communicate by using radio waves to send signals to the antennas on the Earth. The antennas ...
Arunabh Bhattacharya's user avatar
4 votes
1 answer
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Geo satellite - antenna gain contours to heat map in STK

I am using STK to show antenna gain contours on the ground from a transmitter on a sensor on a geo bird that is tracking a receiver on the ground. With good resolution I can create great images that ...
rebee's user avatar
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3 votes
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Satellite Surface Temperature in Orbit

I am trying to calculate the satellite surface temperature in Orbit for Thermal Tests of our satellite. Referring "Space Vehicle Design, D.Griffin, Ch.9, the equations of heat transfer on the ...
v_space's user avatar
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968 views

Can we detect satellite ground station locations?

Is it possible to detect the presence of a satellite ground station in my area? Also can I detect the uplink using a simple Software-Defined Radio (SDR)?
Yossi D's user avatar
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2 votes
1 answer
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Computation slant range d between a satellite and a ground terminal

I am computing the free space path loss by using the following equation: My goal is to compute d (distance between satellite and user) = SE ( see the picture below). Parameters I know: satellite ...
Aid22's user avatar
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10 votes
1 answer
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Does SpaceX expect 1 collision involving one of their Starlink satellites every 2 years?

I read on https://gizmodo.com/spacex-starlink-satellites-dodge-137-objects-daily-1850616506 by Passant Rabie: A new report revealed that Starlink satellites had to make 25,000 collision avoidance ...
Franck Dernoncourt's user avatar
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Sattelite position from TLE

How to get satellite position from TLE without any libraries? Because in Processing there is no libraries like SGP4.
Stanislav's user avatar
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How to compute the pointing accuracy

I was wondering if there's an equation or somewhat intuitive way of computing the pointing accuracy of a satellite? What parameters do I need and how would I go about it?
Lez's user avatar
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3 votes
1 answer
279 views

Geofence - satellite contact time

I need to find the access/contact times for a satellite passing through a random geofence (polygon). Is there a python library or any code to integrate the geofence to the orbit of the satellite to ...
v_space's user avatar
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inter orbital link: frequency band

In technical documentation, it is discussed inter-satellite links. As I understood, under inter-satellite link they mean a link between satellites allocated on the same orbit, LEO to LEO, MEO to MEO, ...
Anna Koroleva's user avatar
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Cell-Free massive mimo for satellite communication design

I am interested in LEO satellite communication and its integration into a 5g terrestrial network. Cell-free massive mimo (CFmMIMO) is a concept used in 5G design. It looks, CFmMIMO can be used if we ...
Aid22's user avatar
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Are most commercial satellites communication satellites?

Is it true that commercial communications satellites account for the largest share of commercially used satellites?
FalconHeavy321's user avatar
1 vote
1 answer
75 views

World communication network coverage in % or dead zones

In the paper "Recent Progress and Future Development in Satellite Communication" written by Ju Han, it is given that only 20% of the land area is covered by signals. I have started to search ...
Aid22's user avatar
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Does the Orbital energy of a satellite in an elliptical orbit depend on the semi-major axis of the orbit?

I am learning about Space exploration and I have the following question: Does the Orbital energy of a satellite in an elliptical orbit depend on the semi-major axis of the orbit? Thanks!
FalconHeavy321's user avatar
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Is it possible for cubesats in walker constellation to communiocate with nearby satellites?

I was wondering if it is possible for cubesats in a walker constellation to communicate with others while they get in near proximity. I was thinking that using an omni-directional antenna would be ...
alex10791's user avatar
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2 votes
1 answer
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Eutelsat 10B satellite appearance

Looking at the SpaceX launch of Eutelsat-10B, which was built by Thales Alenia Space, it seemed to have a rather unusual color. Usually geostationary satellites are either covered with a "gold&...
Sam V.'s user avatar
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1 answer
170 views

What could spacecraft do with much more available power? Are spacecraft power limited?

I'm curious about how spacecraft would benefit having much more power for the same total mass. Solar panels are getting lighter, but would the extra power they could generate bring benefits to space ...
James Craft's user avatar
4 votes
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201 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 ...
jkt's user avatar
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-2 votes
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386 views

Why is so much money spent on launching government communications satellites?

A lot of money is spent on launching government communications satellites that aren’t useful to the public. What is the use for these satellites and why are they considered important enough to use ...
A. N Asker's user avatar
1 vote
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Is there any dataset that are monitoring the grounding electronic charges provided by the satellites?

I would like to know if there are some datasets that are monitoring the grounding electronic charges provided by the satellites
dragontim's user avatar
2 votes
1 answer
797 views

How does one calculate the look angle for non-geo satellites (i.e. LEO, HEO, etc.)

I'm trying to find a way to calculate look angles to not just GEO satellites, but LEO, MEO, and HEO sats. The only calculator I've found myself is here, which was referenced for a similar problem on ...
Imp's user avatar
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How does one generate a formula(s) for an artificial satellite's location at time t given a set of known locations at discrete times?

Given a set of spatio-temporal points in space {(Lat_1, Lon_1, Alt_1, Time_1), ... (Lat_n, Lon_n, Alt_n, Time_n)}, I need a function (i.e. a formula) that takes these points (or subset of points) as ...
Imp's user avatar
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1 answer
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How does a spacecraft know what communication network to use?

Spacecrafts use different networks like TDRSS, DSN, ... to accomplish uplink/downlink. But how does it know which one to use during the mission? At what point does it find TDRSS more suitable than DSN ...
vermissa's user avatar
3 votes
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87 views

Where to find the network topology of Iridium-Next?

This is my first post on Space Exploration. I'll preface this by saying that I just started learning how satellite communications work from a technical perspective. Until a few days ago I had never ...
Wippo's user avatar
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How do satellites ensure they are orientated towards the Earth to allow of clear connections? [duplicate]

As the title says, How do satellites ensure they are orientated towards the Earth to allow of clear connections, whilst having their solar panels face the sun? I understand reaction wheels are ...
Connor's user avatar
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2 votes
0 answers
341 views

How to compute the satellite footprint latitude and longitude for different countour?

Given a satellite coordinates, the antenna gain pattern of the satellite (example a dish antenna at given frequency and with known diameter), the off-nadir angle and the satellite slant range i need ...
Massimo Capozzi 's user avatar
1 vote
1 answer
186 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 ...
Kurt Hikes's user avatar
3 votes
1 answer
111 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 ...
Fred's user avatar
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4 votes
1 answer
202 views

Why was Telstar 1 put in a 952 x 5933, 2.6 hour 44.8° MEO orbit?

Wikipedia says that Telstar 1 was put into a 952 x 5933, 2.6 hour 44.8° MEO orbit but doesn't really say exactly why this particular orbit was selected. Did it perhaps behave roughly like a Molniya ...
uhoh's user avatar
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6 votes
3 answers
840 views

How were Intelsat 1 “Early Bird” and Telstar 1's "hundreds" of simultaneous telephone conversations multiplexed/demultiplexed?

When did they stop routing long-distance analog phone calls through satellites? What was the maximum volume at its peak? contains images, sources and descriptions of both The Intelsat 1 “Early Bird” ...
uhoh's user avatar
  • 149k
-3 votes
1 answer
242 views

Inter-satellite range: how to compute max. range? [closed]

How to compute a distance between 2 satellites if I know its orbit altitude? I know LEO-LEO satellite distance is from 1000 km until ~7000 km. But it should have a calculation equation? EDIT 1 S1, S2, ...
Noel Miller's user avatar
4 votes
2 answers
436 views

How to compute each of these link budget terms?

The terms in Equation are all in decibels (dB), which is logarithmically scaled. In Equation, $P_{rx}$ is the received peak power, $P_{tx}$ is the transmitted peak power, $G_{tx}$ is the transmitter ...
Noel Miller's user avatar
2 votes
1 answer
127 views

Transmit power for low/high wavelength [closed]

I am reading the book: Kaushal, H., Jain, V.K. and Kar, S., 2017. Free space optical communication. New Delhi: Springer India. I have asked before about a reason of choice of wavelength for beacon ...
Noel Miller's user avatar
3 votes
2 answers
354 views

What are the reasons for the specific operating wavelengths chosen for laser communication?

I am reading the book: Kaushal, H., Jain, V.K. and Kar, S., 2017, Free space optical communication, New Delhi: Springer India. The operating wavelengths for beacon and data transmission were discussed....
Noel Miller's user avatar
0 votes
1 answer
182 views

PAT (Pointing Acquisition, and Tracking) system in lasercom

After reading some articles and posting questions 1, 2 I think, the main challenges are PAT (Pointing Acquisition, and Tracking) system and operating environment. We must put the beam onto the ...
Anna Koroleva's user avatar
4 votes
1 answer
395 views

Data rate in optical free space communication systems

Mynaric is one of the main suppliers of laser terminal for free space communication. In one of its latest publications I have read, they will increase the data rate of the last lasercom terminal up to ...
Anna Koroleva's user avatar
4 votes
1 answer
275 views

There are only a few suppliers of optical terminals: what is the reason?

I am conducting research into optical free space communication and small/nano satellites in LEO. I have found only a few companies which supply lasercom (laser communication) terminals (transmitter/...
Anna Koroleva's user avatar
1 vote
0 answers
47 views

Minimum data required to predict passes

What is the minimum amount of information that is required to predict satellite passes. Can it be done with the period, inclination, apogee, perigee and eccentricity only? Thanks
P_J's user avatar
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2 votes
2 answers
1k views

How to compute footprint(size) of beam of sat.system?

I need to compute the footprint (ground area that its transponders offer coverage) of beam diameter. Given different frequencies, distance between a satellite and ground station. I have found the same ...
Adil.Kolenko's user avatar
2 votes
1 answer
166 views

Optic communication: day and night

Will launched time of a laser satellite teminal affect to transmission parameters, as data rate, power …? As I know , the main limitation of lasercom is a direct line-of-sight path exists between a ...
Adil.Kolenko's user avatar
14 votes
3 answers
3k views

Is it possible for LEO satellites to detect a usable signal from regular mobile phones on the ground?

Background Recently I came across a company called ASTS that claims they will be able to launch LEO satellites with the capability to talk with regular mobile phones. I initially wrote their claims ...
0xbad1d3a5's user avatar
1 vote
1 answer
303 views

Receiver and transmitter in RF/optic satellite communication: distance vs data rate v2

The first version of this question is here. I have read the article "Optical communications work best over relatively short distances in space." by Toyoshima, M., Leeb, W., Kunimori, H. and ...
Adil.Kolenko's user avatar
3 votes
0 answers
158 views

What did Intelsat-1 do in 1990 for its 25th anniversary brief reactivation? Could it be reactivated again? Is there a secret code?

Ouch! The 1960s From This Is What Broadband Satellite Communication Looked Like in 1965 The Intelsat 1 “Early Bird” communications satellite, built by Hughes Aircraft Co., was able to relay 240 ...
uhoh's user avatar
  • 149k
12 votes
1 answer
3k views

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 ...
uhoh's user avatar
  • 149k
0 votes
2 answers
124 views

First cylindrical Earth satellite? Last?

Sputnik 1 was a shiny metal sphere, as were it's immediate followers. These days Earth satellites are generally rectangular prisms, either one or a few stuck together. Basically big metal chassis ...
uhoh's user avatar
  • 149k
8 votes
2 answers
715 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 ...
YaelChAv's user avatar
3 votes
2 answers
554 views

What is the theoretical smallest size limit for a phased array antenna that can reach LEO?

Now that one provider is operating a phased array ground-to-satellite internet comm system, others will follow. A frequently asked question is "When can we use Starlink with a sat phone?". ...
SpaceInMyHead's user avatar
2 votes
0 answers
76 views

How to calculate when an areostationary satellite would be unable to talk to earth?

Consider an areostationary (geostationary but for Mars) satellite that communicates to Earth. Since on some orbits, Earth would be behind Mars from the point of view of the satellite, I imagine that ...
user avatar
1 vote
1 answer
92 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 ...
uhoh's user avatar
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