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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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SpaceX 2nd stage or tumbling satellite? WSW to NE over FL

Around 2040 EST We viewed an irregularly flashing object flying from WSW to NNE (roughly) from Jacksonville FL. Is the SpaceX 2nd stage still up there and if so, would it be tumbling and visible? Is ...
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Can I obtain the audio of president Eisenhowers message coming to me from a satellite circling in outer space?

I remember hearing a recording of this speech some time ago. However searching for it again has been difficult, which led me to believe that I probably heard a recreation from someone else. In this qz....
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1answer
125 views

Was the Orbit Pavilion triggered by real communications events?

The October 2016 NASA JPL news article Art Turns Public Eyes (and Ears) Toward Space describes an artistic interpretation of the communications between a number of NASA Earth satellites and ground ...
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1answer
105 views

Is photovoltaic efficiency defined and measured differently for space vs terrestrial applications?

Since the shape (as well as the integral) of the solar irradiance spectrum above the atmosphere is different than that below it, is the efficiency of photovoltaic solar panels defined and measured ...
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1answer
170 views

What is a satellite trap?

I keep hearing about satellite traps, which have something to do with receiving and transmitting satellite communications, but I can't seem to find a definition. The securityaffairs.co blogpost Hack ...
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57 views

What are the space-based optical satellite sensors?

I was looking at a products page for Numerica Corp, and under their product MFAST it said (emphasis mine): Tracks objects in all regimes of space (e.g., LEO, MEO, HEO, GEO) using radar, ground-...
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82 views

What are the effects of orbital reflectors and advertising on scientific observation?

There's a couple of startups and initiatives which are proposing "space billboards" which have been getting a lot of bad press recently. Most of the proposals involve a bunch of cubesats with large ...
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118 views

What was the design failure that Johns Hopkins Applied Physics Laboratory is alluding to?

I was looking through old saved urls and when an old Johns Hopkins Applied Physics Laboratory press release link didn't work, it sent me to the PageNotFound page, where I saw the image below. It ...
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Which robotic spacecrafts have autonomous operation capabilities?

I am searching for an overview of autonomous space robots integrating motion planning capabilities, such as a list of robots (past and present). So far, I have found these robots: Mars exploration ...
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0answers
219 views

How has the angular velocity of Earth changed over the past 100 years?

What is the total change in the Earth's Angular Velocity over the past 100 years? I have read other posts that discuss how much mass has been lifted out of Earth's Atmosphere. I'm trying to get an ...
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0answers
380 views

Laplace Method for Orbit Estimation

I have a question about Laplace angle-only method for orbit determination where the line of sight vectors are being interpolated. I read somewhere that the method fails (due to a matrix being singular)...
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81 views

Satellite Laser Ranging - Relativistic Range Correction

I am not sure whether I have understood the relativistic range correction which plays an important role for precise Satellite Laser Ranging (SLR) correctly. The basic observation equations for this ...
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What main engine used in a series of environmental satellites has failed more than once (according to the GAO)?

A GAO report on NASA's ongoing projects can be found here. On page 70 while discussing the Lucy mission, it says the ... main engine was the same model used on a series of environmental ...
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What would be the equivalent camera performance specification of Earth-imaging satellites, compared to consumer DLSRs?

In order to better understand what Earth imaging cameras are like (as seen in Google Earth) from the point of view of a photographer, I've asked the following. Consumer-grade cameras like DSLRs, ...
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0answers
93 views

Geometry of full global coverage with 4 supersynchronous satellites, 3 or 16 control stations

in order to provide a truly global coverage of the Earth from space, including the polar regions, a minimum of just 4 satellites is required. Placed in precise 63.4 degree supersynchronous orbits, one ...
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323 views

“Deep space” corrections in SGP4; how does it account for the Sun's and Moon's gravity?

The Simplified Perturbations model SGP4 is used to calculate Earth satellite state vectors (position and velocity) using standard ephemeris data encoded as TLEs (Two Line Elements). According to ...
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0answers
404 views

How are composite materials most frequently or most prominently used in satellites and rovers?

I'd like to understand how composite materials (CMs) are used on satellites and rovers. Which parts are made of CMs? If there are numerous examples, then the ones which are particularly large, or ...
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Computing the local orbital frame vector directions and angles of gyroscope direction in the satellite

In the context of the study of a cubesat (little satellite), I am asked to define the local orbital frame and compute the local orbital frame vector directions as a function of time (...
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87 views

Are 2 satellites joined better than 2 apart?

Could new satellites be designed to intercept other older functioning artificial satellites or space junk already in orbit to add weight to the new satellite in order to last longer in orbit?
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203 views

How to find Near Rectilinear Halo Orbits (NHROs)?

Looking all the good questions and answers in this site referent to CR3BP dynamics, periodic orbits, state transition matrices, etc. I wonder: what algorithm or steps do I have to follow to find the ...
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0answers
94 views

How can I plot a precessing orbital plane of an artificial satellite on a polar plot from a TLE in Python?

How can I plot the orbital plane of an artificial satellite on a polar plot from a TLE in Python? Very new to all of this. As I understand it I need to extract TLE's from Space-track.org. Then use ...
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61 views

Can the L1 sunshade idea for climate control be adapted to work in LEO?

There have been a few papers written on ways to put objects at the Earth-Sun L1 point to shade the Earth enough to counter-act global warming. There is a Wikipedia page about it, this paper called ...
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67 views

Finding reference quaternion of a satellite in orbit

How can i find the reference quaternion of a satellite after it has detumbled? I need the quaternion to be able to successfully actuate my payload, which in this case will be a hyperspectral imaging ...
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336 views

Clarify algorithm finding satellite ground track and orbit position

I try to plot satellite ground track. I found lots of formulas but hardly find algorithm which describe how to uses them one-by-one and step-by-step. As I understand the algorithm will be: 1) Get ...
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0answers
89 views

How long is a satellite orbiting at 300 miles going to be visible from horizon to horizon?

Elon Musk has a plan for satellite internet that involves LEO and VLEO satellites. The question I have is how long would a satellite at these altitudes actually be within range before having to ...
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174 views

Has anyone seen an actual spectrum of a satellite made by an amateur photographer?

If you use a shallow wedge prism or very low dispersion diffraction grating (e.g. circa 100 lines/mm) front of a camera, you can photograph the spectra of stars with a modern DSLR camera with a fast, ...
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219 views

Was it a “Soviet military satellite not in any of the catalogs?”

I can't connect to the Tass news item directly http://tass.com/science/896683 but on a SETI page an item dated August 31, 2016 says: An article that quotes the Russian news agency TASS is ...
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135 views

Could electrodynamic tethers power long-term unmanned satellites around the Sun, Jupiter, or Saturn?

Assuming you have the budget to research electrodynamic tether powered unmanned satellites, and you had a cheap way of getting them in to earth low earth orbit, would they be able to use electricity ...
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46 views

Cis-L2 Libration Point Halo Orbit

Queqiao became the first satellite to orbit the Cis-L2 libration point (far side of the moon). Link: https://en.wikipedia.org/wiki/Chang%27e_4 Does anyone have any insight on how to model this orbit ...
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83 views

Parasite Satellite

With computers and technology becoming lighter and is also effected by drag. Could a small satellite that lacks certain systems be designed to utilize an existing satellites systems like radio, solar ...
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45 views

Apply forces such that a satellite reaches a given point in space

I'd like to find out a strategy for solving the following simplified problem. A small spherical craft at $t=0$ has a position and velocity vectors $\mathbf{x_0}, \mathbf{v_0}$ in a zero gravity ...
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41 views

Distributed computational power-sharing and orbital supercomputer

I had an interesting conversation last night with a nanosatellite engineer about how much computational power is required in a nanosatellite constellation and if it's necessary. I had an idea or a ...
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Satellite altitude variances in orbit

I understand that all satellites must have burn corrections to keep their orbits where they are needed. However my question is specifically about what those changes are in magnitude from the desired ...
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Are there any concrete plans to include chipsats for planetary suicide missions?

One of the potential uses for chipsats may be: Chipsats, which are smaller and cheaper still, are seen as disposable sensors that could be sent on suicide missions to explore hostile environments, ...
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How to calculate a Satellite position at a given time

I am trying to write a program to be able to "model" a Low Earth Orbit satellite's position at for a given time in the future. However I do not have a TLE for the desired satellite, I simply have a ...
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132 views

Satellite Orbit-Sun Geometry of Sun synchronous Orbit

What is the difference in satellite orbit-sun geometry of Sun synchronous orbits of 6am local time , 9 am local time , 12 pm local time ?
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106 views

How to compute angular velocity of fluid ring for passive control?

Excuse me, friends. In paper , for passive control with eq.4, how to compute beta? beta is angular velocity of fluid in fluid. the satellite has initial angular velocity, but with filled fluid ring we ...
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attitude determination TRIAD - how are orbital reference frame vectors constructed?

I am trying to fully understand the TRIAD algorithm for attitude determination of a satellite. https://en.wikipedia.org/wiki/Triad_method So so far I know that the vectors $\vec{r}_1$ and $\vec{r}_2$...
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71 views

How to determine an available planetary communication window using orbital mechanics?

For class I have an orbit around Mars at an inclination of 63.4 deg and a base site of 55 deg North and was wondering how to work out the communication window, using orbital mechanics. Orbital ...
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88 views

Elapse Time Of Satellite's Sunrise and Sunset

What is the formula for calculating the elapsed time to sunrise and sunset of a satellite. Example: Satellite to sunrise +00:01:00 Satellite to sunset -00:45:21