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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17
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2answers
3k views

Why is this Planet Labs video wobbly?

Planet Labs recently tweeted ( https://twitter.com/planet/status/1481790983155044352 ) a video showing a Falcon 9 first stage landed on a pad. Strangely, the image looks like it was taken by a camera ...
9
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2answers
860 views

When and why did three-axis stabilization become prominent in geostationary satellites?

Since the very first Sycom 1, geostationary satellites from 1960s to 1980s are cylindrical with solar cells covering the body of the satellite. Such examples include: GOES 1 to 7 AsiaSat 1 and its ...
1
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0answers
63 views

calculating satellite position and velocity from TLE

I'm trying to calculate satellite orbit from the TLE set at first, I used several libraries including SGP4, Skyfiled to get the initial position and velocity of the satellite at the epoch time I know ...
5
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1answer
444 views

Is there any website where we can view live orbit of all satellites to scale?

As the question says, Is there any website or app which has a graphical view of all satellites which are currently in orbit with sizes to scale. An option to view in fast forward is appreciated.
4
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0answers
89 views

Which countries have military satellites in orbit?

Which countries have active military satellite(s) in orbit? And which countries had military satellite(s) in orbit but don't have them anymore (inactive or de-orbited)? Wikipedia says: As of December ...
1
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1answer
158 views

Very slow blinking object — high orbit satellite or some balloon? Any idea?

Could anyone help me to explain? This evening I played with a Gen 3 night vision binocular. I spotted a very slow blinking light 5 hours after sunset. I made a 5 minute video, I but can't attach that ...
2
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0answers
40 views

General range of maximum RPMs used in reaction wheels in spacecraft?

I was wondering what would be the general range of RPMs used in Reaction Wheels (RW) on a satellite, and I have several closely related questions on this topic: It would definitely depend on the max ...
7
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1answer
295 views

What is different between Hill frame and LVLH frame in satellite?

What is different between Hill frame and local-vertical, local-horizontal (LVLH) frame in satellite? I add one figure to show this two frame. reference of figure: Weiss, Avishai, Uroš V. Kalabić, ...
2
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1answer
60 views

Training ML models in space

It's not really space exploration unless space crews need to train new machine learning (ML) models for some new problems they face during their journey but I read this: https://www.technologyreview....
0
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1answer
169 views

Nuclear or Solar power for satellites?

For satellites do they use solar or nuclear for the main power source? I do know that they have both but I do not know which is primary. for an example: Galileo, does it use solar or nuclear?
26
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3answers
5k views

Can Voyager 1 reach the Andromeda Galaxy?

Right now, as of 2021, Voyager 1 has left the Solar System. If it has reached such a great distance, is it possible for it to reach the Andromeda Galaxy? Also, will we be able to still be in contact ...
2
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1answer
71 views

Solid metal fuel for nano satellite thrusters

A South African company is developing a solid metal fuel thruster that was initially researched by NASA but was not further developed, an electric reaction could be used to vaporise solid metal fuel, ...
3
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0answers
67 views

What are the specifications for electrical connectors that can be used for repeated mating in space?

We’re working on an interface between satellites that when docked has to transmit power and data. The interface needs to have a port for transmitting power and data. Majority of the connectors ...
4
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1answer
117 views

How to read stuffin.space data?

In a comment to this question, @PcMan suggested my stuffin.space for satellite data. Now I am not quite sure of how to interpret the data, take for example the following screenshot: Why is the ...
0
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0answers
40 views

Arc length between two satellites [duplicate]

When considering two satellites in the same circular orbit, is it correct to say: The arc length between the satellites is...? Is there a more appropriate term when talking about the curved distance ...
-5
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1answer
94 views

International space station(ISS) viewed from planet earth

Is it possible to view International space station (ISS) using sophisticated Telescopes from planet earth?
7
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1answer
604 views

List of circular satellite orbits for testing inverse square law of gravity

For a high school activity I am looking for a list of (maybe 10 or so) circular satellite orbit data including radius $r$ or diameter of the orbit and orbital period $T$. Then I want to calculate from ...
4
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2answers
609 views

Distance between two satellites

What is the appropriate term for arc length between satellites moving in the same circular orbit?
3
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2answers
162 views

Number of satellites needed for global 4-fold coverage as a function of altitude?

I want to estimate how many satellites (and how many number of planes) are needed for achieving a 4-fold global coverage on earth (global coverage with at least 4 satellites in view in each location). ...
3
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0answers
63 views

How to calculate the phase angle between satellite and sun with the use of skyfield

With the discussion that took place on answer(s) to How to calculate cone angle between two satellites given their look angles? I would like to ask if my proposal solving that question works like ...
3
votes
2answers
242 views

Why haven't we seen more origami in spacecraft?

I remember watching a few videos awhile back talking about origami designs in spacecraft: Origami in Space: BYU-designed solar arrays inspired by origami Engineering with Origami I've only done a ...
5
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2answers
784 views

Is there a way (working or in development) to track satellites in lunar orbit like we track objects in Earth Orbit?

I understand that Earth orbiting satellites are tracked using technologies such as radar, but due to the distance between the Earth and the Moon, they aren't really useful for Moon sats. Is the ...
2
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1answer
76 views

How to calculate the height above the horizon of a geostationary satellite on a given latitude?

Wikipedia's Geostationary orbit; Communications says: Geostationary communication satellites are useful because they are visible from a large area of the earth's surface, extending 81° away in both ...
0
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2answers
55 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 ...
3
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1answer
106 views

How do I get the Landsat satellite's images of the Earth?

I want to get the database of the images taken by Landsat satellite of Earth for a project. I searched and searched and searched, but
2
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0answers
19 views

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

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 ...
2
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0answers
68 views

What other space vehicles were affected by cold welding?

The Wikipedia page on cold welding states that Mechanical problems in early satellites were sometimes attributed to cold welding. But only mentions Galileo as an example of spacecraft were cold ...
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0answers
51 views

Launch excapse system for satellite payloads? [duplicate]

Once a rocket lifts off, there is usually no abort mode that does not involve the destruction of the rocket, and on a satellite launch, the payload. Therefore, expendeble satellite launchers are quite ...
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0answers
62 views

Vela 1A and IMAGE "once were lost, but now are found"; are there any more "lost" satellites thought to still be in Earth orbit?

@BillGray's answer to Where is Vela 1A? Is there any information what its orbit would be like now? says in part: This object was "lost" for some decades. In October 2014, the Palomar ...
3
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0answers
76 views

After the ISS which other artificial satellites are the best candidates to try to resolve in a telescope?

This question was asked on the initiative of the user @uhoh here. I have a Sky-Watcher 10 inch Dobson telescope, equiped with a proper solar filter. Last year, I wanted to observe some satellites ...
6
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2answers
1k views

At which speed and angle should satellite be to orbit in longitude line?

At which speed and angle should satellite be to orbit in a longitude line (on Greenwich line, for example) ? most satellites I know move in latitude lines (equator line), or just a part of longitude ...
6
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0answers
96 views

Measuring and analyzing the tumble of space debris

How well or accurately can we measure the tumble of space debris? I know that we can make ground-based measurements based on light curve data acquired by telescopes. Can tumble be measured from radar ...
3
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2answers
207 views

How many existing satellites have a continuously varying orbit because of human design decisions?

In the space community, there is an assumption that changes to an Earth satellite's orbit are infrequent (other than those due to atmospheric drag). Are there any known satellites designed to ...
4
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4answers
215 views

Do space industry companies want their defunct satellites back?

Space junk debate aside, many large satellite companies (and governments too) are responsible for a large number of both operational and defunct sats that are still in orbit. When other companies or ...
3
votes
2answers
107 views

What type of battery technology does Mars Odyssey use?

The Mars Odyssey orbiter is currently the longest-serving spacecraft at Mars. Launched and put into service in 2001, it continues to take infrared pictures and gamma-ray spectra of the Martian ...
4
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2answers
181 views

Why aluminum is added in Multi Layer Insulation?

Aluminum is a highly conductive material. Instead of insulating the system from heat, it conducts. Multi-Layer Insulation aims to protect spacecraft from extreme heat by acting as a thermal barrier. ...
10
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1answer
549 views

Which satellite constellations are already operational in LEO (Low Earth Orbit)?

I am researching information on active and operational constellations in LEO (Low Earth Orbit) but from what I can see, many missions are still only planned (e.g. OneWeb, Amazon) and the only one ...
3
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1answer
91 views

Could a single CubeSat provide location services on another celestial body such as Mars? Could a constellation do it?

From my understanding, by having two satellites emit a signal simultaneously (carrying atomic clocks to achieve it), a ground device could measure the difference in times of arrival to determine its ...
4
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2answers
122 views

Are there any satellites in geosynchronous orbits that are neither geostationary nor 'wobbly geostastionary' (figure of eight geostationary)?

None of the examples in this question: Are there any satellites in geosynchronous but not geostationary orbits? are nothing like geostationary. They still stay above the one side of the earth. What ...
2
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1answer
95 views

Telemetry: How do we manage to get a message to a tiny satellite that may be millions of kilometers away?

I saw a series of half hour documentaries on various satellites that had been sent out to explore various aspects of our solar system and found myself wondering how we aim our telemetry signals to hit ...
6
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2answers
1k views

What is the density of the earth's atmosphere at an altitude of four hundred kilometers?

What is the density of the earth's atmosphere at an altitude of four hundred kilometers? I want to use it to calculate the drag on something in orbit near the ISS. The Jacchia Reference Atmosphere is ...
0
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0answers
61 views

What would be the most appropriate shape for a satellite going to mars?

What kind of shape would be best for a satellite studying mars?
3
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0answers
176 views

Future trends in Earth Observation and Communications from VLEO; are there any?

Question: In order to better understand the wider market need and uses for Very Low Earth Orbit (VLEO)-enabling technologies, I'd like to ask about future trends in Earth observation imagery and ...
5
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1answer
113 views

Satellites below perigee on Stuff in Space website

A friend of mine noticed that many satellites on Stuff in Space website can reach an altitude lower than their declared perigee, as you can see in the following screenshot: We observed these ...
2
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2answers
122 views

Can we determine the position of an artificial satellite using Kepler's parameters?

I have read that an orbit is defined by Kepler's parameters, so is it possible to determine an exact position of an artificial satellite using those parameters? Forgive me if this is a redundant ...
3
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1answer
72 views

Is there an archive of the Satellite Times magazine from the mid-late 90s?

More of an misc. question. I am looking for the "Satellite Times" magazine which seems like it was in print in the mid-late 1990s. Part of the articles published there could be found at ...
2
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2answers
263 views

Ephemeris output from Skyfield

Is it possible to use Skyfield to propagate a TLE forwards and then output its ephemeris, rather than geometric x,y,z at some point in the future? I've worked through the examples in the API and may ...
1
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2answers
127 views

Why are minimum three artificial satellites required for radio-communication all around the Earth?

Artificial satellites orbiting the Earth have important applications for radio-communication around it. To avoid the blockage of radio-communication around the Earth, multiple satellites can be ...
3
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0answers
76 views

Why are Hubble's magnetorquers angled?

Watching a video on how Hubble attitude control works I saw one portion on magnetorquers. It has four for redundancy but they are angled in a way that looks awkward from a packaging viewpoint, so what ...
3
votes
2answers
160 views

How do I find my coordinates using x, y and z variables and trilateration?

For a school project, I was really interested in finding my own location using information from satellites, by using trilateration (so basically do what GPS are doing but by myself and with some math)....

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