Questions tagged [low-earth-orbit]

Questions regarding Low Earth Orbit or LEO, which refers to orbits at an altitude between approximately 160 kilometers / 99 miles and 2,000 kilometers / 1,200 miles.

33 questions with no upvoted or accepted answers
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355 views

What caused this shadow on Falcon 9 stage 2 w/Jason-3 before circularization burn?

While the image appears bright, the light is just reflected sunlight (from the earth, per the webcast). The circularization burn doesn't start until about T+ 00:55:16 per the SpaceX webcast. But at ...
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260 views

Split cost of bringing 1 kg to LEO

Historically seen, space logistics prices decrease, as shown here, from $20K/kg to expected 1.7K/kg thanks to reusable rockets. But, how does the cost split look like and vary in detail? i.e. "fuel - ...
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90 views

What was the first unplanned “over-the-air” software update of a spacecraft?

From time-to-time spacecraft have had to be rebooted, in one case Voyager 2 mutinied and had to be reprogrammed and in another Opportunity had it's memory "hacked". As far as I know, deep space ...
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157 views

Why have JWST in a Sun-Earth L2 halo orbit?

What is the main reason JWST will be in a halo orbit around the Sun-Earth L2 LaGrange point? There have been questions on this site that ask Why won't JWST deploy in LEO where it is potentially ...
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286 views

What are the disturbing torques on the ISS?

What are the orders of magnitude of disturbing torques on the ISS itself, preferably split into the following categories, but any numbers (with source) will be useful: Gravity gradient Magnetic Solar ...
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135 views

Multiple problems with horizontal launch and cryo storage for Stratolaunch?

The Stratolaunch system claims to be a way to revolutionize launching into LEO. The many problems associate with stress loads for horizontal assembly and the need to carry a rocket to launch altitude ...
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399 views

What level of radiation protection do electronics on the ISS or in LEO need?

The harsh radiation environment in space requires that electronics on spacecraft be "radiation hardened." However, the radiation environment in LEO is not as intense as say a spacecraft traveling ...
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92 views

Has a totally eclipsed Sun been photographed from low Earth orbit?

I'm hoping to get a sense of how much of the corona can be seen during an eclipse of the sun from outside of Earth's atmosphere. Have any photographs been taken in the visible part of the spectrum, ...
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82 views

How much is LEO worth?

I've seen valuations of the space industry at ~$350bn annually. How much of this is coming from LEO vs MEO/GEO?
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422 views

If a sun-synchronous orbit passes over the poles twice a year, how can it have a constant (e.g. 98°) inclination?

I am sooooo confused. The answer to Are sun synchronous orbits possible for any place on Earth? ends with In short, yes, sun-synchronous orbits are possible for any location on Earth. and mentions ...
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I want to simulate the antenna pointing error when tracking LEO satellites

I am trying to simulate the antenna pointing error of our antenna when tracking LEO satellites using TLE data. I am using the Skyfield library in python. First I loaded the TLE data from the Celestrak ...
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149 views

How did three 1.2 meter spheres and a Xe+ plasma contactor keep the Shuttle “grounded”? What did they look like?

Statement of relevance This answer to Highest DC voltage ever intentionally produced in space? mentions particle beam experiments done from the Space Shuttle while it flew through Earth's atmosphere ...
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46 views

Problems with spaceflight high voltage

What problem exists if the surface of the satellite is at a high positive potential in LEO? What is the maximum voltage it could withstand? is there any document about it?
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52 views

Are spacecraft put into Earth orbit frequently equipped with small thrusters to separate their orbits from their co-orbiting rocket bodies?

Brandon Rhodes' retweet says I’ve recently followed @TSKelso as a fun way to keep up with the surprising volume of rocket launches these days, and the new http://celestrak.com viewer shown here is ...
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Why will it take a couple of weeks to complete CRYOSAT 2's orbit raising of a few hundred meters?

The BBC's Esa and Nasa line up satellites to measure Antarctic sea-ice says: Authorisation was given on Tuesday for Europe's Cryosat-2 spacecraft to raise its orbit by just under one kilometre. This ...
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94 views

What does a typical delta-v budget look like for a LEO satellite?

In terms of launch, initial orbit correction, stationkeeping, deorbiting, etc. for a typical 100-200 kg LEO satellite? Is there any source online with specifications for non-private Earth-orbiting ...
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58 views

Angles only Orbit Determination for LEO satellites

I have a script that uses the Gauss method for Prilimanry Orbit determination of satellites using 3 sets of ra-dec and the corresponding LST (adapted from the MatLab example given in the appendix of ...
2
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107 views

How can I calculate the azimuth from an earth station to a satellite

I have computed the ecef coordinates of both the user location on the ground, the satellite's ecef coordinates, as well as other inputs such as altitude, lat, long of both satellite and earth station....
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213 views

Spacecraft-fixed coordinate system

I am working with data from a polar-orbiting satellite (inclination 97 degrees) with limited attitude information. I am trying to define a coordinate system which is fixed with respect to the ...
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153 views

thrusters, force torque, distribution matrix , orbit maneuver

I have a few questions about computing torques and forces. I use the same configuration as in the thesis titled An Attitude Control Sysytem Design Based on the Turksat-1b Geostationary Satellite. ...
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169 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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76 views

How can the delta-V be calculated depending on the launch altitude above sea level?

If we assume that we have a given launcher that is able to produce a $\Delta v$ of 10km/s at sea level takeoff, and is able to reach an LEO of 200km above sea level, what LEO altitude would that ...
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436 views

How can a paint fleck make a window bullseye?

This answer repeats the fact that something as small as a few micrometers in diameter can make a visible bullseye in a window in orbit. I heard it with respect to the space shuttle, and now they have ...
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204 views

How many (presumably friendly) lasers are being shot at us from space? (pew! pew!)

A comment below @A.Rumlin's answer to Is there any spacecraft that is ping-able? links to a Facebook page (in Russian) which shows an astrophotographer's photograph of stars plus a big green flare ...
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66 views

Most efficient (computationally) orbit propagation for simplified J2 effects

I am looking into modeling large scale constellation (hundreds of satellites) and there coverage over earth given a defined conical FOV. The simplified process is a user defines: Constellation (...
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91 views

Was the ISS closer to Baja California or California when this ISS press event started? When exactly did it start?

The NASA video Expedition 63 Inflight with New York Times, Fox News, and USA Today - July 7, 2020 begins with NASA astronaut and Expedition 63 commander Christopher Cassidy discussing with an ...
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40 views

HDEV Goodbye Video- similar projects planned?

I just found that nice "Goodbye HDEV" video on the Columbus-Eye-Projekt-Webpage. (http://columbuseye.rub.de/) Seems like the HDEV-housing is already burned during re-entry. Does anyone know ...
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57 views

What is the longest manned re-entry from Low Earth Orbit ever recorded?

What is the record for the longest amount of time that a manned spacecraft has taken to re-enter from low Earth orbit (LEO)? I would prefer the duration between the beginning of the re-entry burn ...
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120 views

Would a Hohmann transfer within LEO be useful?

Hohmann transfer is often used between a lower LEO orbit and MEO, GTO, GEO or beyond. But if the target is a high altitude within LEO, how would a direct ascent compare to ascent to a lower orbit ...
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161 views

Attitude of the upcoming “Orbital Reflector”; will it result in good visibility?

There's a new (passive solar) orbital reflector, called the Orbital Reflector. While Mayak (Маяк) was a crowdfunded project at Moscow State Mechanical Engineering University and the Humanity Star ...
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678 views

What is the speed of ISS relative to ground surface?

Is it 7660 m/s or (7660-460)m/s? If it is the former then the ISS orbits about the Earth at 8120 m/s. I think it should be (7660-460)m/s relative to ground based on this orbital period formula, $$T=...
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782 views

How to calculate azimuth and elevation angles from satellite point of view of a ground station?

How to find azimuth and elevation from satellite of a ground station when yaw, pitch, roll, lat, long position of satellite and lat, long position on ground are given? ...
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152 views

How to clear the way for a space elevator?

In the answer to this question about space elevators, the poster mentioned that the elevator cable would pass through a debris cloud as it moved through lower orbits. I presume most of that material ...