Questions tagged [communication-satellite]

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

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Why didn't NASA launch communications relay satellites outside the asteroid belt to communicate easily with interstellar satellite?

I came across with nasa's voyager and other interstellar satellite, just thought that if they build a relay satellite which situated outside asteroid belt or nearby to Saturn & Jupiter, to ...
Ashay baghele's user avatar
1 vote
0 answers
44 views

Simulation satellite channel in Matlab

Where can I find values for delays and pdp to simulate the satellite-ground channel? PS 3GPP TS 36.116 document contains multi-path delay profiles used for the performance measurements in a multipath ...
Aid22's user avatar
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6 answers
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Why is there never enough room on satellites to hold all the equipment needed?

Why can a satellite run infrared and other forms of data collecting equipment and stream live results back for the public, but not take photos or video? I am guessing there is never enough room to ...
William devries's user avatar
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Impact of Satellite Movement on Signal Processing Between Tx and Rx:

I am researching how the movement of satellites affects signal processing between a transmitter (Tx) and receiver (Rx). Satellites can function as either transmitters or receivers. The movement will ...
Aid22's user avatar
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Have spherical dish antennae been used with Molniya satellites to avoid switch-over signal loss?

Molniya-orbit communication satellites work well for ground locations near the poles. These high eccentricity, highly inclined orbits, with a period of 12 hours, “loiter” for about 6 hours over the ...
Woody's user avatar
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5 votes
2 answers
527 views

What does a "handover" really mean in satellite communications?

I am working on simulating a satellite constellation and I keep coming across the term "handover". My general understanding is that a handover is when a ground station switches its connected ...
Luca Petrescu's user avatar
1 vote
1 answer
137 views

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
275 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
0 answers
100 views

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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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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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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0 answers
98 views

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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135 views

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
289 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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25 views

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
2 votes
0 answers
70 views

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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4 votes
1 answer
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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
84 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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0 answers
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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
2 votes
1 answer
72 views

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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3 votes
1 answer
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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
0 answers
292 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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1 answer
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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
0 answers
42 views

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
3 votes
1 answer
1k 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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2 votes
0 answers
77 views

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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0 votes
1 answer
106 views

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
0 answers
97 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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0 answers
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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
394 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
214 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
118 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
207 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
861 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
301 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
526 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
137 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
4 votes
2 answers
432 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
223 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
414 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
296 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
56 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
173 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
408 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
171 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
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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
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