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.

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3answers
487 views

If Steve is at 300 km, and SWARM is >440km, how did SWARM measure Steve's temperature?

How did ESA measure Steve's temperature using the SWARM spacecraft? Please explain how the measurement is really done, don't just mention an instrument's acronym. I did a quick dump of TLEs for ...
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Could Steve have hurt the ISS?

The BBC News article Aurora photographers find new night sky lights and call them Steve says: A group of aurora enthusiasts have found a new type of light in the night sky and named it Steve. ...
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Is bypassing LEO more efficient when launching to Venus or Mars?

According to the table in the Wikipedia article on Hohmann transfer orbits, when traveling to Venus or Mars, the Δv to enter a Hohmann transfer orbit from Earth's orbit is less than the Δv from LEO: ...
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Why is OA-7 launching atop an Atlas V?

After replacing the old refurbished NK33 engines with newer RD-181 engines on Antares, and the successful OA-5 launch with Cygnus to the ISS, why is the next launch of Cygnus occurring on an Atlas V? ...
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Vacuum launch, essentially free after system built

Outside Earths atmosphere is the vacuum of space and its immense power. If a cylindrical tube of sufficient strength and size were built tall enough to reach the edge of atmosphere would it not be ...
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Why would Space Cube 1.0 have so many On-Orbit Upsets over South America?

I was reading about the Advanced Hybrid On-Board Science Data Processor - SpaceCube 2.0 Space Cube 2.0 and I saw maps of computer upsets in orbit recorded by Space Cube 1.0 on slides 8 and 9. What is ...
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1answer
163 views

How much brighter-than-expected could a spent rocket body become?

In a comment below an answer to the question What could have made a satellite appear to move side to side while near the horizon? I've said: Actually a satellite with flat surfaces - especially ...
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Reconnaissance satellite altitudes

I was lately reading about making pictures of ISS. The pictures are not really great from "home telescopes". I was wondering what the usual altitude of espionage satellites is, given those pictures ...
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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 ...
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2answers
645 views

What is the final conclusion about 'object M'? What happened?

I've looked at Is Iridium launch object M a test satellite? and I don't understand what seems to have happened. The Iridium launch produced 11 orbiting objects when only 10 Iridium satellites were ...
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What goes into the planning and execution of the deployment of groups of LEO satellites?

I was among many watching SpaceX's exciting OrbComm-2 mission (Falcon-9 Flight 20, 22-Dec-2015), and besides the first successful landing of a 1st stage after an orbital mission, the deployment of the ...
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1answer
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Deorbit LEO debris with a higher orbit laser?

A couple of days ago I asked Can a laser be used to clear the launch path of a rocket? turns out this is not a good plan but the answer by Hobbes suggests the idea of clearing debris with a laser is ...
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Can a laser be used to clear the launch path of a rocket?

Military grade lasers shooting down incoming missiles have been in the news since Ronald Reagan was the US president. The problems, as I recall are mostly about diffusion in atmosphere. The Kessler ...
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How could we make a fair comparison between space rockets regarding their payload mass in low Earth orbit and Earth escaping?

I was searching for comparisons between space rockets regarding their payload mass in low Earth orbit and Earth escaping. First one to see capability of the space booster (the first stages) and second ...
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How long does it take to get into Low Earth Orbit? [duplicate]

I've seen varying times for spacecraft/rockets getting into LEO, e.g. according do the Mercury-Atlas 7 Wikipedia article, it took just over 5 minutes to get into a 259x154km orbit, whereas the Saturn ...
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For constellations of circular LEO satellites, are there allocations of available “slots” in altitudes?

The BBC article SpaceX aims to launch internet from space discusses the SpaceX proposal for a dense array of 4,425 LEO satellites distributed among 83 orbital planes in five inclination groups as ...
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SpaceX's 4,425 satellite constellation - what's the method to the madness?

The BBC article SpaceX aims to launch internet from space discusses the SpaceX proposal for a dense array of over 4,000 LEO satellites for global internet coverage, and links to SpaceX non-...
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Does electrostatic discharge pose a threat for docking or capture in a 700km polar orbit?

Is there any charging / ESD threat for a docking program at 700 km orbit?
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What kinds of radiation hit the ISS?

Does Earth's magnetic field block (or divert) only lower energy radiation while the hardest, high speed heavy ions, run through to LEO? Are the hardest rays dampened? Do the van Allen Belts, not far ...
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Building a ultra-small almost space vehicle

I'm quite interested in small rockets-balloons that can reach more than 50km, thus I want to build one myself (With my school financial support). I just want it to carry like a 350g-450g equipment. ...
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Atmospheric influences on satellite imagery [closed]

I need to know if there's any relationship between the drag force of any point in LEO with the quantity of particles or something like that that are flying in the air that makes quality of the ...
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3answers
196 views

When and how will the Chinese spacestation reenter? [duplicate]

China's first space station Tiangong-1 is expected to deorbit in late 2017. Are NASA or others tracking it? What is its position and condition at present time?
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The strange orbit of Ofeq 11 - how does it (actually) do this?

I assume the retrograde orbit ($\theta_{inc}=142°$) is a side-effect of geography - ocean overfly access only lies West of the secured launch site - this article in Spaceflight 101 makes several ...
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How to get semi-major axis from TLE?

This should be fairly straightforward, but, how do I get the semi-major axis (a) from at TLE. For example if I have the TLE: ...
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For which applications are LEO and GEO substitutable?

This article, this article, and this earlier question indicate that, given enough satellites in LEO, it's possible to substitute between GEO and LEO. The first article and the question have some ...
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How would a bulk payload like fuel (instead of delicate technology) change boost to LEO optimization?

This answer suggests that if a payload were simply bulk propellant, such as LH2 and LOX, and not delicate technology such as an interplanetary probe or communications satellite, then there may be some ...
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What kinds of things have been tossed out of the ISS?

Cubesats are (ir-)regularly deployed at very low velocity from the ISS, and they don't usually have propulsion. This tells me that the delta-v is enough to guarantee to those in charge that their ...
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136 views

What would be the postal/delivery address for an orbiting vehicle? [closed]

It's possible/likely that one day we'll be able to post/mail/deliver stuff to a non-terrestrial vehicle, such as an orbiting vehicle or an extraterrestrialLy landed vehicle, without involving the ...
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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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1answer
229 views

Would lunar flyby be less costly in delta-v than direct change from ISS's to Hubble's orbit?

The question Has anything ever executed an orbit change such as between ISS and Hubble? has a in interesting answer. It made me wonder, would something like the (patented) Lunar Flyby technique use ...
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582 views

Can Earth magnetic field be used for attitude determination in LEO?

…or, how well is the Earth magnetic field mapped? Three hallotrons (simple, cheap, robust, tiny, low-power devices) aligned in three axis can be used to determine the direction of local vector of ...
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583 views

What definition of “LEO” does SpaceX use when specifying payload capability?

Please forgive me if I am asking a dumb question. I am a little curious about the orbital parameters of "LEO" used by SpaceX on many occasions specifically those related to payload capability. ...
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452 views

How do launch and stationkeeping fuel costs vary with altitude?

I'm not a physicist or an engineer, so my apologies if I messed up any technical details. I've looked through the SE and found a few questions that touch on this issue (this one gets at the benefits ...
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1answer
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What would be the incremental cost of launching 1 ton of LOX/LH2 into LEO? [duplicate]

I am asking this question in a context of feasability of orbital fuel depots. I understand that cost/kg estimates exist (2-14 k$/kg): What is the current cost-per-pound to send something into LEO? ]),...
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Coefficients for linear tangent steering law

Given certain simplifying assumptions, a "linear tangent" steering law is optimal for orbital insertion of a launch vehicle: $$\tan \psi = a\cdot t + b$$ i.e. the tangent of the flight path angle ...
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Is it possible to covertly put an EMP weapon into an ISS-like orbit by masquerading it as a legitimate launch?

I'm writing a sci-fi novel and I need some clarification on some technical issues. An HEMP is an high-altitude EMP. A 400km high, high-yield nuclear explosion over Kansas could "switch off" all the ...
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224 views

Is it possible to deliver enough LEO satellites with one launch to substitute for one in GEO?

Rough estimates shows that having around one hundred satellites would be enough to observe a single spot on Earth continuously and via peer to peer communication deliver that information to an earth-...
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1answer
582 views

What would have been the absolute maximum LEO payload of a two-stage Saturn V?

I read about the Skylab 1 mission in which SA-513 was used to lob the Skylab OWS into orbit. One source (http://forum.nasaspaceflight.com/index.php?topic=12519.20) gave some payload masses: Total ...
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134 views

Could we launch a rubble pile simulant to LEO for astronauts to practice on before visiting natural milligravity objects?

There are proposals and maybe serious plans to send astronauts to asteroids or Mars' moons, objects which are a few kilometers or just a few meters in diameter. I call them "milligravity" objects ...
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MOM's NOT-so-sun-synchronous orbit about Mars - how large is it's J2?

edit: See my supplementary answer below for additional information. @Hohmannfan nailed it. This question and answer started me wondering - how big is the J2 (oblateness) term of Mars' gravity ...
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877 views

Would the Saturn V have been able to send more mass to TLI if it had a lower earth parking orbit?

After reading into the topic a little, I've come across a number of increases to the Saturn V's LEO and TLI performance over the course of the Apollo program. Early moon missions sent between 133t and ...
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Earth-Moon system barycenter

Given that the barycenter of the Earth-Moon system lies somewhat below the surface of the Earth, but not at its geometric center, why do our man-made satellites still orbit the Earth's geometric ...
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What advancements towards Mars were made during Scott Kelly and Mikhail Kornienko's “1 year” journey?

First there's the annoying part where everyone says it was a year but the actual flight time was less than a year. It is only a year in the sense that they launched and landed in March. But getting ...
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Is the Paramagnetism of Liquid Oxygen Ever Considered in Engine or Tank Design?

NOTE: I'm asking if this material property is ever considered. I'm not asking "do you think it should be considered". I'm pretty sure someone has considered it, and I am hoping to track down some ...
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What was the Apollo service module propellant used for on the LEO missions?

The Apollo service module carried a lot of propellant for performing the following tasks on a Moon mission: Mid-course correction manoeuvres to and from the Moon. Braking the entire CSM/LM stack into ...
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What is a “Double Iridium Flare” and how close can the two satellites be?

I just saw the term "Double Iridium Flare" and I'm wondering how close two Iridium satellites might actually be (in distance (km) and angle). I found this video as an example. ...
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1answer
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Can I launch a homemade rocket from the ground that can reach LEO? [duplicate]

If I had the time and the financial means to do so (and legal rights), could I design, build, launch, and deliver a small (very small) payload to low Earth Orbit? I think it would be awesome to put a ...
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959 views

What will happen to the Russian messages flash drive?

I saw a video today of a flash drive being thrown into space from the ISS (http://www.bbc.co.uk/news/science-environment-35487441). What will happen to this flash drive? Will it burn up in the ...
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3k views

How long can a LEO Satellite maintain its orbit if it loses all power?

Basically if it becomes a rock, how long until it reenters and burns up?
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Why are the ISS' Sequential Shunt Units not on the inside?

Recently Tim Peake and Tim Kopra carried out an EVA to replace a failed Sequential Shunt Unit, some form of electrical regulator for the solar panels, on the outside of the ISS. Why aren't these ...

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