Questions tagged [low-earth-orbit]

Questions regarding Low Earth Orbit or LEO, which refers to orbits at an altitude between approximately 160 kilometers / 100 miles and 2,000 kilometers / 1,200 miles.

46 questions with no upvoted or accepted answers
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7
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90 views

Does NOAA still plan to deploy all twelve Cosmic-2 GPS radio occultation satellites?

In the 2014 Space News interview of Jim Bridenstine (now NASA administrator, then member of the US house of representatives for Oklahoma) Q&A With Rep. Jim Bridenstine (R-Okla.) appears: Space ...
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360 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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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 ...
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How was the high rate of degradation of Hubble's main mirror initially predicted? Why did it turn out to be lower? Were cosmic rays really a concern?

This answer to How long was the HST initially supposed to work? in Astronomy SE quotes Assessment of Options for Extending the Life of the Hubble Space Telescope: Final Report as follows: Hubble was ...
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229 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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274 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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How to calculate sheath area

Suppose we have a cubesat in LEO, if the metallic surface of the satellite is at a positive potential it will attract electrons from the ionosphere plasma, the current collected will be I = J * A, ...
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346 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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92 views

How to find a vector's elevation angle with respect to a point on Earth?

tl;dr: Spacecraft's antenna should point to a ground station but there is a pointing error. I want to express the error as a vector rather than a simple angle that a dot product provides, so that I ...
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74 views

How problematic is debris for Starship storage/depots?

So with the recent announcement that Starship has been selected as NASA's HLS (which is pretty radical), it's raised a question in me that been around for a while. For HLS; a Starship storage(depot) ...
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134 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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138 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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407 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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167 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 ...
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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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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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444 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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43 views

Design and optimization of a Sun-synchronous repeating ground track orbit constellation

I am currently researching about this topic and am very new to this. Have no clue how to go about designing a group of imaging satellites (constellation) that are sun synchronous with repeating ground ...
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How is Prospero doing now? Was it really heard in 2004 and have there been recent attempts to contact it?

Screenshot from the excellent historical review in Curious Droid video Black Arrow : The Lipstick Rocket - A Very British Space Program with a photo of Prospero or at least a representation thereof. ...
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36 views

Biggest orbital inclination change done in Earth's orbit

Generally orbital inclination change is said to be (fuel) expensive. What is the biggest orbital inclination change (in degrees) done in Earth's orbit for an orbiting object? Can this be broken down ...
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79 views

Bronze material compatibility for mechanism exposed to LEO

I'm looking at using a worm gear for a latching mechanism on a spacecraft that's destined for a LEO trajectory. The mechanism is on the outside of the spacecraft, but the worm gear itself would be in ...
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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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53 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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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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168 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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235 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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172 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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193 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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86 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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438 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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Calculating body frame X vector's look direction in GEO (NED) frame from roll, pitch and yaw data, is this correct?

I have roll, pitch and yaw angle values for a LEO satellite. Satellite orbit frame and spacecraft body frame are defined as LVLH. The satellite position and velocity are given in ECI/GEI frame. I have ...
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51 views

How much would it cost to launch a 0.5U Satellite?

I have seen the figures for 1U, 3U and 12U Satellites such as those provided here, but I have been unable to find pricing for the launch of a single 0.5U or 0.25U satellite. I have seen many academic ...
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50 views

Is it possible to determine whether a spacecraft is in the thermosphere or in the exosphere?

The Earth's thermopause is varying greatly between 500 km (310 mi) and 1000 km (620 mi) altitude. If a craft orbits inbetween these altitudes, or reaches them at some point of their orbit, is there ...
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What is the fastest that ParkinsonSat spun? Did it vary with solar activity?

Why would photon pressure be needed to keep ParkinsonSAT Spinning? explains that it was equipped with surfaces that resulted in a sunlight-induced torque which have ...succeeded in keeping the ...
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Calculating angular deviation from LEO magnetic field

The situation I need to calculate pointing errors for a satellite that points along Earth's magnetic field. The satellite's position and orientation are given to me w.r.t ECI J2000. The orientation is ...
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254 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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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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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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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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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 ...
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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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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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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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909 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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996 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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155 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 ...