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.

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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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Is there a standard 'low orbit' for other solar system bodies?

Is there a standard or convention for what 'counts' as a low orbit for other solar system bodies? I'm currently writing code for computing arbitrary Hohmann/ patched conics transfers, and I am looking ...
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What are these squiggly lines in Jonathan McDowell's tweets about Yunhai-1?

Anton Petrov's new video Another Satellite Collided in Space, But Everyone Missed It Until Now (below) is fun to watch, and links to Jonathan McDowell's tweet string which begins Space-Track catalog ...
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How big will a space billboard have to be to be visible?

So recently there's been the news story about how SpaceX is launching a billboard to space (space billboards are an approximately bi-annual occurrence). This "billboard" is a cubesat that ...
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Why was the Rossi X-ray Timing Explorer decommissioned in 2012? Why wasn't it deployed another ~100 km higher where drag would have been a lot less?

The Rossi X-ray Timing Explorer (1995-074A) was an incredibly prolific space telescope between 1996 and when it was decommissioned/deactivated on January 5, 2012. It reentered the atmosphere soon ...
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What is final positioning of rideshare satellites (like transporter-2 mission) and how do they get there?

Looking at deployment of transporter-2 mission I did not see any information about the final position of these satellites (relative to the second stage or to each other) and how do they get there (...
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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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Cubesat surface material

In wikipedia I read that the structure of the cubesat are made of aluminum alloys of 7075, 6061, 5005, and 5052. Is this the surface layer of the satellite or it is necessary to cover it with kapton ...
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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 ...
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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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Can a LEO based satellite constellation revive the analog radio or TV era?

Many analog terrestrial radio and tv transmitters have been replaced by digital ones like DTT and DRM technologies. Analog radio signals include FM, MW and even SW. Although the quality of reception ...
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What orbits are Starlink satellites now deployed into? How low to do they go on their first perigee?

In my answer to Delta-V of Starlink Satellites I ballpark spherical-cow envelope-back estimated 190 m/s with 2 kg of krypton based on raising only from a 445 km circular orbit to a 550 km circular ...
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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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In situ Fuel in LEO / MEO

I have been thinking on controlled de-orbiting of Satellites. You can carry a supply of conventional chemical fuel, and use it to apply a delta-V that would de-orbit them. There are also methods of ...
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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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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 ...
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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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What is the acceleration in an orbit decaying due to air resistance relative to one not decaying?

This answer to Is there an upper limit for the internal size of space stations? has this paragraph: Finally, if you are stuck ["stranded" in the middle of a room in a space station filled ...
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What does 'a nudge' mean in the context of rocketry?

The following paragraph is from a wired.com article: When I visited this past fall, SpinLaunch employees were still unpacking from the move. As we walked among giant sheets of steel, Yaney explained ...
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How much is known about those liquid metal droplets orbiting the Earth? (e.g. sizes, composition, orbits...) Are any actually tracked?

The question Orbit Guardians - bs, right? mentions a company proposing a smallsat that will capture then give a roughly 200 m/s retrograde "kick" to liquid metal NaK alloy droplets in LEO ...
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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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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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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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Is Starship planned to fly directly to the ISS without first stage? Is it even possible?

I'm having difficulty understanding how/if Starship and/or Super Heavy could be used to deliver crew to LEO. Is it expected to deliver astronauts to the ISS Crew-Dragon-style, but without the 2nd ...
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Where can one find the accelerations due to high-order terms of the geopotential model?

The expression for the orbital perturbation due to J2 ($\mathbf{a_{J2}} = [a_r \ a_s \ a_w]^T$) as well as its derived effect on the argument of perigee and the right ascension of the ascending node ...
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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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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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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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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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Determining the launch period for Hohmann transfer

How do you determine the day of a specific launch? I know there are launch windows but they only refer to the time at which a spacecraft must be launched. For a LEO it is apparently 365 days, but what ...
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Why 53º orbits for Starlink?

In the UCS satellite dataset, I see a very modest number of non-Starlink LEO satellites around 53º (see graph below). Conversely, Starlink satellites are regularly deployed around that inclination. ...
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How much does smallsat launch to LEO cost?

In early 2021, SpaceX, Rocket Lab, and Virgin Orbit list prices as follows: ...
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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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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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Do we have an effective way to dispose of space debris at LEO?

There are a lot of articles and news that companies have plans on how to get rid of space debris. But I never found a single proven and reliable method. Perhaps I was looking in the wrong place? Or ...
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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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What is the extent of on-orbit refueling experience at the ISS? Which fuels? which spacecraft?

In a discussion associated with this answer a comment includes the following: The ISS is the only spacecraft in the world that has experience with regular on-orbit refueling. What is the extent of ...
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Small satellite launcher to LEO dedicated launch vehicle [duplicate]

well today i was thinking, why nobody do something like the SS-520 but comercial? a small rocket entry dedicated to launch a cubesat, that probably go to have a lot of adventages and probably is realy ...
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Conceptual reusable orbital launch engine prototype for nanosatellites [closed]

I have realised that the process in which we go to space is highly inefficient and we should create a hypersonic spaceplane which take offs and goes to low earth orbit to release nanosatelite and ...
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Payload capacity of a rocket

Why does a rocket have far more payload capacity when placing an object in LEO compared to when it's placing the object in farther orbits, like on the Moon? If a rocket has sufficient thrust to take ...
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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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IMLEO orbit height

Initial Mass in Low Earth Orbit is a well defined cost metric for space missions [1]. However, this is somewhat subjective since it depends on the orbit height. My guess is that there is a ...
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What is the name of the area on Earth which can be observed from a satellite?

The following image shows Earth and the trajectory of the ISS. A green line indicates which part of the earth can be observed from the ISS simultaneously. What is the name of this line or this area?
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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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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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Is an electric fuel tug from LEO to moon orbit economically feasible?

Does it make economical sense to use an electricaly powered fuel tug to supply a moon landing program with fuel? I am imagining an architecture of launching a 25t payload of mostly fuel into LEO which ...
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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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Does the Newton-Rhapson solution to Kepler's equation diverge?

I have the following simple solution to the Kepler's equation which uses newton-rhapson iterative technique. I have read various papers about the initial guess and divergence near an eccentricty of 1, ...
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Why use a Mars orbital Earth return vehicle for sample return?

NASA's plan is to use two separate missions to bring home the drill core samples that the Perseverance rover will take. The samples will in plan be picked up by a landed mission and launched to Mars ...

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