Questions tagged [communication-satellite]

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

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What would be the first noticeable consequences to the general public of widespread satellite destruction?

What would most likely be the first thing I, as an average citizen of a developed nation, notice, if within a matter of hours, all major commercial and government satellites were to be destroyed in a ...
Duncan McKirdy's user avatar
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-...
uhoh's user avatar
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26 votes
9 answers
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Can a satellite orbit Earth so that it always has the Moon in line of sight?

Could a satellite, without too much fuel consumption for station keeping, orbit the Earth so that it always has a line of sight to the Moon? It would need a near polar orbit which precesses in tandem ...
LocalFluff's user avatar
26 votes
4 answers
12k views

Does the International Space Station get TV?

For obvious reasons the ISS cannot get cable TV. Can the ISS get the new digital air TV or satellite TV using an issued dish and receiver like a house? How would that be done compared to how it is ...
Muze's user avatar
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25 votes
2 answers
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Is it normal for the US Space Force to warn companies about a possible collision (conjunction)?

I've read a German news article today (Golem.de) stating that there was a conjunction between a Oneweb satellite on its ascension course and a SpaceX satellite. The US Space Force warned Oneweb that ...
Arsenal's user avatar
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17 votes
1 answer
3k views

What is carrier lock and bit lock?

I'm not sure if this question belongs here or in Amateur Radio, but during the acquisition of signal from New Horizons on New Year's Day, I heard the controllers call out "carrier lock", "symbol lock",...
OZ1SEJ's user avatar
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16 votes
2 answers
3k views

Why are obsolete geostationary satellites re-orbited above the geostationary belt?

That seems a bit counter-intuitive, because in an orbit above the belt, the satellite would eventually lose gain velocity, so its orbit would intersect the orbital plane of the geostationary ...
Mark's user avatar
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16 votes
1 answer
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Can communication satellites be used in lunar orbit?

Because the moon always has the same orientation to earth, if we want to have communications with manned or robotic explorers on the far side some type of relay would be needed for communication. ...
James Jenkins'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
14 votes
1 answer
1k views

How many dead sats near GEO?

It's my understanding a geosynchronous satellite will put itself in a graveyard orbit just before it dies. How many dead sats are in GEO or in neighboring graveyard orbits? What is their total mass?
HopDavid's user avatar
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Are Molniya orbits used apart from Russian communication satellites?

Molniya orbits are popular with Russian communication satellites, because they spend a lot of time at high latitudes. Europe and Canada are also quite far north. Do any European, American, or ...
gerrit's user avatar
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13 votes
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Are commercial communications satellites in GEO being constantly monitored by telescopes?

I was trying to look up GOES-17 in Spaceflight101 but got sidetracked in the search result and ended up reading this thread about AMC-9, which links to the YouTube video Rough cut video of AMC-9 ...
uhoh's user avatar
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13 votes
4 answers
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What is the most popular programming language in space?

For the purposes of clarification - will include machine code generated by a programming language on earth. - 'in space' includes anything in orbit and deep space transit. - special mentions of ...
CodingMatters's user avatar
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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12 votes
1 answer
3k views

How much will SpaceX's constellation of Internet satellites cost?

SpaceX has a plan to launch up to 4K satellites to provide global Internet access. Is there a reasonable estimate of how much this constellation would cost to launch? Also, as the minimum number of ...
PearsonArtPhoto's user avatar
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12 votes
2 answers
699 views

How can just making the ground broadcast stronger neutralize a zombie(sat)?

In April of 2010 the Geo-not-so-stationary satellite Galaxy-15 stopped responding to ground commands. It operates as a "bent-pipe" or Transponder system, which means - roughly speaking - it will ...
uhoh's user avatar
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11 votes
2 answers
2k views

Do antennae on the ISS have to constantly move to maintain data links?

In this question and answer pair I see that the ISS can maintain data links to earth through direct access to ground stations as well as through the TDRSS geostationary satellite network. What kind ...
uhoh's user avatar
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11 votes
1 answer
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Will Curiosity and the Mars 2020 rover be able to communicate with each other via a Mars orbiter?

Curiosity's UHF antenna on sol 2439 Could Curiosity and the Mars 2020 rover communicate with each other via the MRO orbiter ? And would it have advantages ? (Like: " I just saw a meteorite, and it'...
Cornelis's user avatar
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11 votes
2 answers
3k views

What (actually) makes Iridium "the world's only truly global mobile satellite communications company"?

In this article about how the SpaceX anomaly will affect Iridium it says: In its official website, Iridium describes itself as "the world's only truly global mobile satellite communications company....
uhoh's user avatar
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11 votes
2 answers
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Why do geosynchronous satellites appear to oscillate in North-Southward direction? How to I trace out their path on the surface of the earth?

During the course of a day, the geosynchronous satellite's position in the sky forms a 8-like figure. I'm having trouble visualizing the movement of geosynchronous satellite when viewed from the ...
Alec Smart's user avatar
11 votes
1 answer
2k views

How does QUESS, China's quantum communications satellite experiment, relay entangled signals?

China launched the Quantum Experiments at Space Scale (QUESS) on the satellite called MOZI or Micius today, which will be used for quantum communications between China and Europe. Popular Science ...
called2voyage's user avatar
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10 votes
6 answers
6k views

Is it possible to replace Internet with LEO satellites?

Bulk information regarding anything in this world is available in a single touch through Internet. My question is whether it is possible to replace this Internet with a constellation of Cubesats in ...
Romean's user avatar
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10 votes
2 answers
2k views

What does "clearing of C-band spectrum" mean and why will it cost Intelsat a billion dollars?

From "Intelsat files for bankruptcy" One of the primary catalysts for restructuring the balance sheet now is Intelsat’s desire to participate in the accelerated clearing of C-band spectrum under ...
Organic Marble's user avatar
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 ...
Franck Dernoncourt's user avatar
10 votes
1 answer
700 views

Why do the geosynchronous TDRS satellites have this distribution of inclinations?

From the Tracking and Data Relay Satellite System (TDRSS) option on Celestrak's NORAD Two-Line Element Sets Current Data TLE page I've compiled current TLE ...
uhoh's user avatar
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10 votes
1 answer
1k views

How can OneWeb constellation succeed where Teledesic failed?

Teledesic: 1994 backed by Microsoft Inclination: 98.2 degrees (sun-synchronous) Altitude: 700 km 840 satellites OneWeb: 2014 backed (?) by Google Altitudes: 800 or 950 km 650 satellites This is a ...
Deer Hunter's user avatar
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10 votes
1 answer
1k views

How much krypton is stored on a Starlink satellite?

How much krypton (fuel) is there for the krypton-powered ion thrusters on Starlink satellites and how long does it last?
Jacob's user avatar
  • 101
9 votes
3 answers
2k views

Do satellite uplink/downlink signals spread or leak into space?

Satellite communication generally involves three types of nodes: the ground station (also known as teleport), the satellite in geosynchronous orbit, and the satellite receiver/transceiver. I am ...
JaceVoracek's user avatar
9 votes
3 answers
3k views

Could a smartphone really transmit to satellites in a space based internet system?

Space based internet systems, like the one recently proposed by SpaceX and Google, are said to use satellites to communicate directly with end users, without using cellular ground stations. But how ...
LocalFluff's user avatar
9 votes
1 answer
393 views

What do large, modern communications satellites look like inside (roughly at least)?

Modern communications satellite in GEO are big, majestic beasts. They are quite large and voluminous. They can sport quite an array of antennas and handle huge bandwidths and multiple communications ...
uhoh's user avatar
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9 votes
1 answer
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)?
akum's user avatar
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9 votes
1 answer
815 views

Can I use Iridium as a receiver network for my satellite?

One of the operational costs for a satellite in orbit is maintaining a receiver ground station. Would it be feasible to send an Iridium transceiver along with my satellite, and then operate it from my ...
Jacob Krall's user avatar
  • 1,368
8 votes
2 answers
1k views

What will be "unique" about upcoming SES-9 GTO transfer profile by SpaceX?

In the SES-9 mission press kit, SpaceX mentions: "Given this mission’s unique GTO profile, a successful landing is not expected." What is considered "unique" about this transfer orbit's profile? ...
uhoh's user avatar
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8 votes
1 answer
818 views

How much time does it take to circularize a GTO orbit using ion propulsion?

SpaceX launched two GEO comsats, and is about to launch two more, that use all-electric ion propulsion. Now, I'm wondering, how much time would it take to actually make a satellite like that ...
radex's user avatar
  • 1,642
8 votes
2 answers
2k views

What are these very large, square panels on Inmarsat 5?

Question: What are these very large square panels on Inmarsat 5's? They seem to each have an extremely reflective mirror-like flat/smooth tiled-appearing side, and a nearly black side with a lot of ...
uhoh's user avatar
  • 149k
8 votes
2 answers
795 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
8 votes
2 answers
778 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-...
uhoh's user avatar
  • 149k
8 votes
1 answer
4k views

How low is VLEO? (FCC's newest approval for SpaceX)

Engaget's SpaceX gets FCC approval to deploy thousands more internet satellites says SpaceX's plan to build a global, high-speed wireless internet network using satellites has taken another step ...
uhoh's user avatar
  • 149k
8 votes
1 answer
331 views

Are the SpaceBEEs still "illegal" or did they eventually receive approval to operate?

This answer to Might ISRO's 2018-004 launch be at least a technical violation of the Outer Space Treaty by India? clarifies some of the actions taken against Swarm Technologies for launching some ...
uhoh's user avatar
  • 149k
7 votes
2 answers
5k views

Difference between Tundra and Molniya orbits?

This excellent answer nicely describes both Tundra orbits and Molniya orbits. They are both repeat groundtrack orbits with periods of rational fractions of a sidereal day, and both have inclinations ...
uhoh's user avatar
  • 149k
7 votes
3 answers
821 views

Could a communication satellite that fails to reach GEO be repurposed?

When a launcher's upper stage fails to put a commercial communication satellite in geostationary orbit, it cannot be used as intended. But could it be used in satellite-to-satellite communication ...
LocalFluff's user avatar
7 votes
2 answers
2k views

How do we track the exact location of the spacecraft which is millions or billions of miles away from us?

How do we track the exact location of the spacecraft which is millions or billions of miles away from us? What things do we study for tracking purpose? How exactly do we predict?
Pras4's user avatar
  • 335
7 votes
2 answers
1k views

When there is more power than needed, are satellite photovoltaics shunted or open circuit?

I saw the word "shunts" in this answer about DSCOVR's upgraded photovoltaic arrays when it was unmothballed and readied for space. Reading it, I get the idea that shunts are used to dissipate the ...
uhoh's user avatar
  • 149k
7 votes
2 answers
1k 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 ...
uhoh's user avatar
  • 149k
7 votes
2 answers
636 views

Is secure communication in space important?

How important is secure communication in space? Science-related research is often made public, but does that mean all communications must be unprotected?
Pras4's user avatar
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7 votes
1 answer
529 views

How could RCA Satcom III have been completely lost? (Or was it?)

This answer to What “missing satellite” was part of the story of CNN's debut? quotes the 1981 UPI Article The RCA Satcom III-R commercial communications satellite, designed to... as follows: The ...
uhoh's user avatar
  • 149k
7 votes
1 answer
436 views

What is the expected lifetime of observable Iridium flares? [duplicate]

I enjoy spotting and occasionally attempting to photograph Iridium Flares: (Iridium flare with airplane trail) They're caused by sunlight reflecting off the antennaes of the satellites that make up ...
James Thorpe's user avatar
  • 1,315
7 votes
1 answer
293 views

How has the brightness of SpaceX's Starlink constellation changed since May?

Shortly after the launch, before full orientation of the solar panels and raising of the orbits, the Starlink satellites were surprisingly bright and easily seen with the naked eye. Back then, I heard ...
SpaceBread's user avatar
7 votes
1 answer
344 views

What is a "critical mass" equivalent of number of satellites on LEO that would initiate chain reaction of destruction if 2 of them collide?

If a satellite is destroyed and blown to multiple small pieces of debris, each one of these pieces has tiny probability of destroying another satellite, creating more debris which now will have even ...
Mariusz Sakowski's user avatar
7 votes
0 answers
462 views

Were solar concentrators on HS-702 just a stop-gap measure until triple-junction PV cells were available?

According to Gunter's Space Page discussion of early versions of the Hughes HS-702 Bus: The first version of the 702 used solar arrays with concentrators. These concentrators tended to early fogging, ...
uhoh's user avatar
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