Questions tagged [artificial-satellite]

Questions about objects in orbit which are human made, such as communications and GPS satellites, orbital observatories and space stations, and other man-made object in permanent or semi-permanent orbits around the Earth, other celestial objects, aside from the Sun, or even other satellites. Not to be confused with non-orbited man-made objects in space, that are usually referred to as "probes", or simply "spacecraft".

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Once Starlink is fully deployed how many satellites will be visible at any given moment?

So the GPS system has 31 satellites in an orbit of 20,180 km. Most of the time there are at least 3-4 satellites 'visible' (visible from a signal reception point of view) at any given moment. The ...
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How many navigational satellites are in operation as of 2020?

GPS (USA) - 75 Global Positioning System navigation satellites have been launched, 31 of which are operational, 9 in reserve, 3 being tested, 30 have been retired and 2 were lost at launch Beidou (...
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How many weather satellites were launched until today (2020)?

How many weather satellites were launched until today, how many are still operațional and which countries have the most such satellites? China has 17
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What operating systems do Chinese satellites use?

Which operating systems are most frequently used by China for satellites?
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Why can't I just use dot product angles to get satellite vision of a point on Earth?

Right now I'm using MATLAB and can easily get the ECEF coordinates of the satellite and the point on the Earth. Since ECEF is cartesian, why can't I just rearrange: $$ r_{es}\cdot r_{ps} = \|r_{es}\| ...
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Is it allowed to interact with research satelites / rovers using the radio?

Let's say I have a SDR (software defined radio) like the HackRF One at home, access to a huge amplifier circuit and a giant antenna (at my university). Is there a law that prohibits receiving / ...
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157 views

An orbit in the corner of isosceles right-angled triangle

Is it possible to have a non-escape orbit that is equidistant to two celestial bodies (for example, Earth and Mars) at all times? If possible, how much does it cost to keep an object (which is much ...
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1answer
128 views

Why does the Deep Space Atomic Clock have such a short mission?

The Deep Space Atomic Clock has a short mission of only two years. How it can be useful for space operations if its operating for such a short time? Additionally I would like to ask if there are or ...
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What does the [-] symbol means in satellite names?

Some satellites in the databases have this "[-]" mark at the end. For example "IRIDIUM 39 [-]" and "GLOBALSTAR M038 [-]" which in databases like www.space-track.org or ...
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How a spy satellite eavesdrop on another satellite?

I recently read about Mentor-4 (also alled USA-202 or NRLO-26), a gigantic US spy satellite (operated by NRO and the CIA) with a possible dish radio antenna of 100 meters in diameter located in GEO. ...
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What stage of a Scout G-1 rocket enters orbit?

Last night I saw a Scout G-1 rocket body part called 1986-088B (according to COSPAR) with my binoculars. I researched a little and found that these rockets had 4 stages, called Algol, Castor, Antares ...
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Is the use of whipple shields on satellites common?

How common is the use of whipple shields or of any micro-meteor and debris shields in general for satellites in low earth orbit , I couldn't find any relevant statistics on the internet, a rough ...
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When did photographic film stop being used in satellites?

Some early observation satellites took pictures on photographic film and the film was dropped towards Earth and picked up by airplanes (e.g. Corona). What was the last satellite to use photographic ...
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1answer
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Get dates when a satellite has performed maneuver from historical TLE data (python)?

I have been recently acquainted with orbital mechanics and am trying to do some analysis on the subject. Since I don't have subject matter expertise, I am at a crossroads with trying to decide that ...
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1answer
102 views

Can the solar panels on satellites (such as Juno) rotate?

Can the solar panels on deep space satellites (specifically Juno) rotate? Do the antennae on deep space satellites (specifically New Horizons) rotate? Or is everything static and the entire satellite ...
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1answer
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Do space organisations take the positions of space junk and satellites into account when launching?

There are so many satellites orbiting Earth now at various altitudes and there is quite a lot of space junk floating around as well. Now although there are so many satellites and so much junk up ...
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Why does NORAD make TLE data public?

If I understand correctly, NORAD tracks thousands of satellites as well as pieces of space debris and publishes TLE files representing their orbital position and motion that are updated regularly. It ...
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Have any satellites been lost or damaged on their way to the launch site (ground/sea transport)?

On our sister site Travel Stack Exchange, someone asked about carrying a cubesat on a plane in hand luggage and is worried about damage or loss (or not being allowed on the plane). Several answers ...
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1answer
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Does every satellite operator build and operate their own ground station?

I'm thinking especially of small-time operators. Like if a high school team puts a cubesat into space, do they also put an antenna on the school building and just put up with limited accessibility ...
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2answers
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How do large thermonuclear explosions on the ground affect satellites in LEO?

High altitude nuclear explosions will completely render electronic devices on the ground useless (unless protected, with lead coating for example). How are satellites affected by such explosions? ...
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1answer
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How are satellite operating modes implemented?

It is pretty simple to find documentation about satellite operating modes behaviour when trying to develop satellite onboard software (example of safe mode behaviour on wikipedia, or on researchgate), ...
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1answer
67 views

How are satellites, rocket launches and other space programs affecting the earth’s rotation? How will it be affecting living beings?

Want to know the effects of the active satellite, rocket launches and space programs that affect earth rotation? how? And their effects on living beings due to effect in earth rotation?
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1answer
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Considerations in producing satellite to smartphone communication

Recently, the company Lynk has been able to conduct direct satellite to smartphone communication. While the article only references the capacity for downlink to the phone, what difficulties must be ...
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1answer
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long sequence of satellites moving west to east?

yesterday (27/3/2020), 20:00, I was on high ground in central switzerland and looked south. in the clear night sky, I saw what I think could have been satellites: linear trajectory, high speed, ...
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What did I see just before the ISS but on a different trajectory?

I live at 49.99N, 8.57E. Today we had exceptionally clear skies. I was looking out a window towards the South between 7:48pm and 7:52pm local time (central european) when I noticed a strange light ...
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3answers
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Could a horseshoe magnet help a satellite stay in orbit?

If a horseshoe magnet was attached to a satellite orbiting the Earth, would the interaction of the Earth's magnetic field and the horseshoe magnet's magnetic field result in the magnet being propelled ...
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Where can I find data on satellite orbits?

I'm an enthusiast who'd like access to satellite orbital data to simulate / plot trajectories of manmade satellites (of any kind) on my home computer. Where's the best place for me to find this kind ...
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3answers
164 views

Are there any related groups of satellites that are in a line of 6 or more in a row?

02/03/20 0450hrs, in Bradford, West Yorkshire, Uk. I saw a satellite going across the sky, it was not too bright and was followed by another and then 4 more they were equally spaced. I would say they ...
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1answer
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Was there a spacecraft that was clearly the first to be put in a polar orbit?

Was there a first spacecraft put in a polar orbit? It might not be clear if it's too hard to say what high inclination orbit is or is not polar, for example if 91 satellites were launched in 0, 1, 2.....
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1answer
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Use of carbon nanotube based black colourings like Vantablack in space

I've seen several articles talking about the ways in which Vantablack and similar substances could be used in space as a replacement for black paint. For example, they could be used on the optical ...
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Why does Himawari-8 have problems with the Sun from 19th February to 19th April?

This weather site uses provides meteorological imaging from the Himawari-8 Earth observing satellite in GEO. https://www.cwb.gov.tw/eng/ The web site contains the following item: ...
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What percentage of a satellite's total budget goes into its launch?

Been trying to do some personal market analysis of the space market, and realized that there doesn't seem to be any kind of statistic or average regarding how much percentage the launch of a satellite ...
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1answer
320 views

What did Sputnik-1 sound like? Did it use multiple tones?

Radio transmissions from Sputnik-1 could be heard on short wave radios around the world. Questions: A carrier signal only would not be particularly audible to an AM radio listener, was it modulated ...
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2answers
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What was the first use of analog to digital conversion in a satellite?

This answer to Do the Voyager probes transmit analogue or digital data? states that the Voyagers sent only digital data. This is no doubt mostly because analog data was digitized and store digitally ...
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How to see Iridium Flares (if possible) in 2020 and beyond?

On December 27th, 2019, Iridium 97 burned up in the atmosphere and there was a "#Flarewell" celebration. However, according to this website which seems to be VERY detailed, there are still 5 ...
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3answers
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How fast do Starlink satellites (SpaceX new satellites) rotate around the earth?

I'm specifically interested in knowing how long they take to do a full circle around the earth but don't find any info. Could anyone help me?
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How can I plot satellite's trajectory from three different TLEs to detect any deviation on path with time?

I have obtained TLE information of a satellite from space-track.org for three different times. I am trying to study any deviation of the satellite trajectory from its usual path. Here I am comparing ...
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1answer
462 views

What does “MSR” represent in the context of this predicted satellite conjunction?

In a series of four tweets starting with this one (found in 2 satellites will narrowly avoid colliding at 32,800 mph over Pittsburgh on Wednesday) 1/ We are monitoring a close approach event ...
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1answer
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How did two satellites end up in almost the same orbit except moving in opposite directions?

In a series of four tweets starting with this one (found in 2 satellites will narrowly avoid colliding at 32,800 mph over Pittsburgh on Wednesday) 1/ We are monitoring a close approach event ...
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1answer
165 views

Why does it take Spaceway 1 (satellite) two or three months to dump 73 kg of bipropellant?

I read on https://arstechnica.com/information-technology/2020/01/directv-races-to-decommission-broken-boeing-satellite-before-it-explodes/ (mirror): In the time available, DirecTV said "it will be ...
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1answer
162 views

Why is “Terminator Tape” electrically conductive?

A 230 foot long tape deployed from the satellite Prox-1 greatly reduced how long it took to deorbit. The tape was described as electrically conductive. Was that property intended to help the ...
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3answers
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How do two-line element sets handle rev numbers > 99,999?

In a two-line element set (TLE), five characters in line 2 -- columns 64-68 -- are for the rev number. (https://en.wikipedia.org/wiki/Two-line_element_set) But some satellites have been around the ...
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454 views

Why is the NORAD Catalog number of SpaceX's Starlink's “Darksat” both 71130 and 44972?

@BowlOfRed's answer to Which of the recently launched Starlink satellites is the coated one? links to Celestrak's supplemental table for Starlink. https://celestrak.com/NORAD/elements/supplemental/...
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How are rocket launches scheduled?

With all the satellites and other objects already in space; how exactly are launches scheduled and coordinated? Is there some kind of clearinghouse? How do the mega constellations affect the ...
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1answer
110 views

Analytical treatment of relative positions between satellites?

I have been searching the internet for estimation of relative position between two satellites. However, all sources seem to be pointing to methods used for proximity operations, where the math ...
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2answers
119 views

Extraction of elevation data from ICESAT-2 dataset

I need icesat2 elevation data for DEM validation process. I have been trying to extract elevation data only from icesat-2 dataset that i downloaded from earthdata but unable to successfully extract ...
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What is the proper terminology for the process of a satellite entering a planet's shadow? [closed]

What is the proper terminology for when a satellite or spaceship passes into a planet's shadow or night side? Is it crossing the terminator? Passing into eclipse (or something better)? If there is a ...
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1answer
119 views

What Earth satellite remained in orbit the longest before reentering?

@BillGray's excellent answer in September 2018 mentions that the Soviet magnetospheric research satellite 1977-093A (NORAD 10370) was expected to reenter the atmosphere in 2019 due to effects ...
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2answers
431 views

What is the reason for secondary oscillations in apogee and perigee plots for objects 41332 and 41333?

This answer provides quite interesting plots of apogee and perigee for objects 41332 and 41333. The primary (sine wave -like) oscillations are probably due to perturbations caused by potential ...
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563 views

Can dust be in orbit around a spacecraft which orbits the Earth or Moon?

In the title above, Can dust be in orbit around a spacecraft which orbits the Earth or Moon? let's define "in orbit" to mean gravitationally bound to the spacecraft long enough to go around it a few ...

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