Questions tagged [communication-satellite]

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

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3 votes
3 answers
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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 ...
5 votes
3 answers
2k views

Main differences between 5G and Starlink? [closed]

I wonder which one is better in terms of whole if considered. Speed, latency, reach, accessibility and affordability.
1 vote
0 answers
45 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 ...
1 vote
6 answers
3k views

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 ...
0 votes
0 answers
63 views

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 ...
3 votes
0 answers
72 views

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 ...
5 votes
2 answers
530 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 ...
5 votes
2 answers
781 views

Are relay stations possible between planets?

I recently participated in a hackathon where we were looking at various space-related challenges and one that we considered was communications between Earth and Mars. The hackathon is over now but I ...
1 vote
1 answer
146 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 (...
1 vote
1 answer
278 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 ...
4 votes
1 answer
149 views

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 ...
3 votes
0 answers
102 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 ...
4 votes
1 answer
1k 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)?
2 votes
1 answer
746 views

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 ...
3 votes
0 answers
275 views

Why so many little pieces of "space tape" on this communications satellite?

Maxar's own blogpost Power and Propulsion Element: Five Questions with Maxar’s Tim Cole contains an image with the caption The ABS-2 spacecraft at Maxar’s Palo Alto, California factory before its ...
10 votes
1 answer
4k views

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 ...
0 votes
0 answers
100 views

Sattelite position from TLE

How to get satellite position from TLE without any libraries? Because in Processing there is no libraries like SGP4.
0 votes
0 answers
136 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?
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 ...
0 votes
0 answers
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, ...
4 votes
0 answers
143 views

How will Amazon's constellation differentiate itself from SpaceX's and OneWeb's?

The New York Times' Amazon Satellites Add to Astronomers’ Worries About the Night Sky says: Much of the attention on these strings of satellites has been placed on the prolific launches of SpaceX and ...
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 ...
4 votes
1 answer
868 views

Are most commercial satellites communication satellites?

Is it true that commercial communications satellites account for the largest share of commercially used satellites?
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 ...
0 votes
0 answers
62 views

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!
6 votes
1 answer
3k views

Why 53º orbits for Starlink?

In the UCS satellite dataset, I see a very modest number of non-Starlink LEO satellites around 53º (see graph below). Conversely, Starlink satellites are regularly deployed around that inclination. ...
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&...
3 votes
1 answer
176 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 ...
4 votes
0 answers
301 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 ...
-2 votes
1 answer
393 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 ...
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
2 votes
3 answers
1k views

Point Ahead Angle and Doppler Shift Frequency Changes Calculation with the tangential/radial velocity component for Inter-Satellite Link

While calculating the Point Ahead Angle we work with Tangential Velocity vector component and to calculate the Doppler shift i.e changes in frequencies, we work with Radial Velocity Vector component. ...
27 votes
1 answer
5k views

SpaceX's 4,425 satellite constellation - what's the method to the madness?

The BBC article SpaceX aims to launch internet from space discusses the SpaceX proposal for a dense array of over 4,000 LEO satellites for global internet coverage, and links to SpaceX non-...
4 votes
2 answers
434 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....
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 ...
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 ...
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 ...
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 ...
2 votes
0 answers
74 views

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 ...
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 ...
1 vote
1 answer
410 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 ...
2 votes
0 answers
398 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 ...
1 vote
2 answers
149 views

How did Syncom-3 achieve eight stages of frequency doubling? I only see seven in the block diagram

@BlueCoder's nice answer to Syncom-3 was the first geostationary satellite. Anyone know of a description of the onboard electronics? mentions that the the master oscillator was doubled eight times to ...
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 ...
5 votes
2 answers
591 views

After 21 years of silence how and by whom was OSCAR-7 first identified as functional?

This 2017 comment below an answer to What is the oldest artificial satellite still in use? says: But it should be mentioned that AMSAT-OSCAR 7 was silent between 1981 and 2002 for 21 years. It was ...
3 votes
1 answer
91 views

Puzzler: Why higher solar phase angle (SPA) allows for many more feasible FastKD (kinetic deflection) communications satellite “hijacking” missions?

Space.com's advert-laden Repurposed communications satellites could help save humanity from an asteroid impact ends with: The study results were presented at the Planetary Defence (sic) Conference ...
5 votes
2 answers
465 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 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 ...
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” ...
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 ...

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