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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Tradeoff between a LEO-LEO vs LEO-GEO data relay

For both commercial and government entities alike, the need for reduced turnaround time in payload delivery (e.g. for optical or synthetic aperture radar images) has led to the development of data ...
Shawn Lim's user avatar
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Why didn't Crew 8 launch to an elliptical orbit with an apogee closer to the altitude of the space station?

Crew 8 launched to a 191x215km orbit (ref), but the ISS is orbiting at 425km (ref). I'm curious as to the reason why they didn't launch into, for example, a 191x425km orbit initially.
phil1008's user avatar
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Does the dawn-dusk orbit maintain the inclination with respect to the ecliptic plane?

I'm trying to understand the mechanics of sun-synchronous orbits, specifically the dawn-dusk orbit. If I understand correctly, the RAAN rotates around the plane of reference of the Earth, which is the ...
popeye's user avatar
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Does it economically cost the same to launch a satellite into LEO and GTO?

I was doing some research about how much $/kg it costs to launch a satellite into GEO. I came across several sources that lists info for LEO: https://ourworldindata.org/grapher/cost-space-launches-low-...
Yi Qiang Ji's user avatar
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Bundle Protocol/Licklider Transmission Protocols needed for TM case in cubesat as per CCSDS standard?

As per CCSDS standard, there is no ARQ mechanism present for Telementry(TM) case. Based on spec it will be taken care by upper layer protocols. So in this case, can we use simple FTP for Cubesat? or ...
codeflow's user avatar
5 votes
2 answers
476 views

Propulsion options for orbital transfers after release from space elevator

In a recent discussion of cost estimates of hypothetical space elevators it was mentioned that a space elevator is (obviously) well suited to bring payloads to a geosynchronous orbit while reaching ...
Peter - Reinstate Monica's user avatar
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Has propulsion utilizing solar sail / drag effects of solar panels achieved orbital rendezvous? If yes, is there any utility for clearing space junk?

It has been proposed to use solar panels as solar sails and drag control by alternately feathering panels during different phases of orbit. It is claimed this can alter light pressure and drag enough ...
Woody's user avatar
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Starlink Dishy parameters and satellite recognition

I have two questions: What are the antenna parameters of Starlink dish antennas (like antenna gain, directivity, etc)? Is there any way for me to know which satellite my Starlink dish is ...
babibooooooo's user avatar
12 votes
3 answers
3k views

How does a satellite's mass affect its fuel consumption to maintain orbit?

Given two otherwise identical satellites in identical orbits, the more massive one's orbit decays more slowly from atmospheric drag: $F=ma$, same $F$ (drag), bigger $m$, so smaller $a$ (decay). So ...
Camille Goudeseune's user avatar
3 votes
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Typical external temperature profile for a LEO satellite

I bumped into a question regarding LEO orbit. Is an external temperature profile available in literature as a first approximation for thermal analysis? I bumped into articles mentioning that the ...
Enrico's user avatar
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Definition of "stable orbit"

I often struggle with the term "stable orbit" for objects in earths sphere of influence, since all real orbits are affected by disturbing forces. Sentences like: It is not possible to ...
CallMeTom's user avatar
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LEO Satellite Service / Coverage Time Calculation for a Ground User

I want to determine the time interval during which a ground user is in the coverage of a particular LEO satellite. I only have knowledge of the user's geographical location and the satellite's TLE (...
Black Dagger's user avatar
2 votes
1 answer
167 views

GMAT LEO spacecraft simulation

I started using GMAT, I have to design an LEO of an AEOLUS Satellite and I have the TLE of the launching. My question is how do I plug the TLE numbers into the spacecraft section (Keplerian element ...
Shada sabri's user avatar
2 votes
1 answer
131 views

Ground station : DVB-S2 TBS-6903 Receiver to communicate with a LEO Satellite

I am working on a project to develop a ground station that communicates with a LEO Satellite in X Band via the DVB-S2 communication standard using off-the-shelf components. It appears that the TBS-...
M.FAKHFAKH's user avatar
3 votes
1 answer
93 views

How much of the small (1 mm - 10 cm) LEO debris are electrically charged?

Upon investigation of Soliton based LEO debris detection, most research require that the debris is electrically charged. So I would like to know what is causing the debris to be charged and how much ...
not2qubit's user avatar
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How much of what we see as “satellites” is space junk?

Ground observers using naked eyes see several LEO objects per minute under good observing conditions, and many times more with binoculars. These are usually referred to as “satellites”. Many are, ...
Woody's user avatar
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Given historical TLE’s, how do I determine the path/orbit/LLA of a satellite for a given historical period?

Im trying to get the historical Lon/Lat/Alt of a starlink satellite. I'm using TLE's from space-track and Skyfield to calculate latitude, longitude and altitude of satellites for a given date range. ...
AGS's user avatar
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How do I calculate the maximum northern and southern latitude a LEO satellite can image?

How do I calculate the maximum northern and southern latitude a LEO satellite can image? What parameters would I need?
pottie's user avatar
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Orbit prediction for satellites using the Kepler model

I would like to know how to model the motion of satellites in orbit using Keplerian, i.e. develop a simulation model that tracks paths of satellites using Keplerian orbits in Python?
Racky Alvin's user avatar
-1 votes
2 answers
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Higher density medium tube from sea level to space for travel

Is it theoretically possible to build a strong sealed tube from Earth's sea level all the way to Space, fill it with a medium (such as water) that has a higher density than humans. And then humans ...
Saurabh Goyal's user avatar
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Understanding the difference between pointing knowledge, pointing accuracy and pointing stability?

In terms of specifications for satellite Attitude Determination And Control System (ADCS) hardware, my understanding is that pointing knowledge is for attitude determination, whereas pointing accuracy ...
v_space's user avatar
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Negative elevation angle

What does it mean to have negative values of elevation angle from the low-Earth orbiting (LEO) satellite? Can the negative values of elevation angle be useful?
TThoye's user avatar
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10 votes
1 answer
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Would the reflected sun's radiation melt ice in LEO?

If they tow a big chunk of ice to LEO, shielding from the Sun will be required. My question is, would they have to shield from Earth as well?
Star-SpaceX's user avatar
2 votes
1 answer
64 views

Inter-satellite/Inter-platform communication requirements

I am studying Inter-satellite/Inter-platform links and would like to compute the link budget: Satellite-Satellite or HAP to HAP ( high altitude platform). For my computation, I am looking for a ...
Aid22's user avatar
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TLE along track error to miss a contact opportunity in UHF

Update: (following @GregMiller's comment): Lets suppose a spacecraft has performed a boost and not all ground stations received the update, lets suppose the difference between the pre and post ...
patowski1981's user avatar
2 votes
1 answer
501 views

Analyse the Doppler effect in non-GEO satellites: calculation of Doppler shift ( frequency)

I want to compute the Doppler frequency for LEO/MEO/GEO satellites. For the calculation I am using the following equations: $$V= \sqrt{(G \cdot \frac{M}{R+h})}$$ - satellite speed. Height dependent $...
Aid22's user avatar
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3 votes
1 answer
380 views

Minimum number of satellites to achieve 24 hour coverage at LEO for a single point

If I want to cover one single point on earth with 24 hour coverage using LEO satellites, how many are needed at minimum and what would be their orbit
jadine's user avatar
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3 answers
157 views

What would be the advantages and disadvantages of a LEO Earth observation satellite, carrying both Electro optical and SAR payload be?

An Indian startup, is trying to build a multi- payload satellite having both optical and SAR sensor on the same satellite. The look angles of the these payload are quite different and it is very ...
Bharath Simha Reddy's user avatar
1 vote
2 answers
638 views

Elevation angle for a non-GEO satellite

I want to calculate the elevation angle of a Non-GEO satellite with respect to a ground terminal. The information I have to solve this: Instantaneous Longitude, Latitude, and Altitude of the non-GEO ...
Black Dagger's user avatar
2 votes
1 answer
153 views

Equatorial LEO Satellites

Which satellites orbit in an equatorial LEO ($0^{\circ}$ inclination) around Earth? Or where can I find information regarding this that will give me the exact location of that satellite (longitude and ...
Darmstadtium's user avatar
9 votes
1 answer
1k views

I'm building a CubeSat for a short 8-day mission in LEO followed by a fairly quick reentry, what range of orbits to consider?

The goal of this CubeSat mission is to demonstrate CubeSat construction, operation, and communication in Low Earth orbit for 8 days or longer. Why the short mission time? Because the mission lacks ...
Deko Revinio's user avatar
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4 votes
0 answers
320 views

Polarization mismatch between a LEO satellite and ground terminal

Cross-polarization loss between a circularly polarized antenna and vertical or horizontal polarized antenna is known to be -3dB. This is one of the reasons why Circular Polarized antennas are ...
jkt's user avatar
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2 votes
0 answers
75 views

Determining a suitable 'low orbit' for an arbitrary airless body

A while back, I asked this question here, dealing with finding a standard low orbit for a solar system body. The answer I received was mainly in the context of a body with atmosphere. This answer gave ...
Ingolifs's user avatar
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1 vote
1 answer
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Space Debris? Gecko toes to the rescue?

Removing orbital debris in a safe, robust, and cost-effective manner is a long-standing challenge, having serious implications for LEO satellite safety and access to space. Orbital rendezvous is ...
Woody's user avatar
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2 votes
1 answer
189 views

Problem with ISS state vector (ECEF or ECI ?? rotating frame problem ?)

I have a serious problem with some satellite state vector I use. I got the cartesian coordinates of ISS (X,Y,Z) but do not know in which frame unfortunately. So I tried to plot them in 3D to check if ...
StateVect21's user avatar
4 votes
1 answer
349 views

Implemented analytical orbit propagator

Anybody knows about reliable open source implementation of analytical orbit propagator (for a generic orbit, given the initial state and not TLE)? Possibly including up to J2 and drag also. I have ...
Pietro De Marchi's user avatar
5 votes
1 answer
292 views

Draper Semianalytical Satellite Theory (DSST) C/C++ version

Anyone knows where one could find the Draper Semianalytical Satellite Theory (DSST) semi-analytical propagator code in C/C++? I know Orekit includes the Java version inside its code. An in general if ...
Pietro De Marchi's user avatar
4 votes
1 answer
97 views

Optimal numerical method to solve BVP for optimal low thrust control

I need to solve a boundary value problem (BVP) for an optimal control in case of low thrust trajectories optimization. I want to include the J2 perturbations to the Edelbaum solution (multiple ...
Pietro De Marchi's user avatar
1 vote
1 answer
128 views

What are the product terms shown here representing an orbit?

I can compute Kepler parameters from a given TLE using Skyfield. I am checking the satellite information from this website and the orbit is represented as $$ 546 \times 548 \text{ km} \times 53.1 \...
jkt's user avatar
  • 153
4 votes
4 answers
475 views

Could a third stage be added to Starship?

SpaceX has predicted that Starship will be able to lift up to 150 tons to LEO. Could some of the payload that it will carry have a third stage? If so could that save another flight of Starship since ...
The Rocket fan's user avatar
1 vote
0 answers
96 views

Could it be more cost-effective to refuel with on the lunar south pole produced methalox instead of refueling methalox in LEO, on the way to Mars?

In the article Prominent volcanic source of volatiles in the south polar region of the Moon it is calculated that 8 x 109 kg $CO_2$ has been vented billions of years ago by pyroclastic events in the ...
Cornelis's user avatar
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5 votes
2 answers
1k views

Revisit time estimation for a SAR constellation

I am studying satellite coverage analysis and I have read something about revisit time I did not understand. you can increase and increase the number of satellites to further improve the revisit time, ...
Sfusfina's user avatar
4 votes
2 answers
395 views

What does LMO mean?

I know that LEO means low Earth orbit. I thought that LMO would mean low Mars orbit, but my friend said it means low Mercury orbit. Does LMO mean low Mars orbit, low Mercury orbit, none of those or ...
The Rocket fan's user avatar
5 votes
2 answers
838 views

Weaponizing the Starlink constellation

Starlink aims at having tens of thousands of satellites in orbit in a few years. At any given point in time there will be a large number of satellites close by any inhabited places, including the ...
Peter - Reinstate Monica's user avatar
6 votes
1 answer
615 views

Would satellites going into a rendez-vous show a difference in potential leading to an arc between the structures?

I'm researching into satellite rendez-vous. I know (NASA-HDBK-4006A) that in space (more precisely LEO) there is a plasma made up with electrons and atomic ions and a 'plasma potential'. I also learnt ...
Joan's user avatar
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2 votes
1 answer
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Significance of measure of dispersion in Orbit determination output

I am trying to understand the significance of specifying dispersion measure of 3 sigma or ½ sigma along with Orbit determination output. I am assuming a Space Craft in LEO sun-synchronous orbit of ...
Soumajit's user avatar
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7 votes
1 answer
10k views

How long can the SpaceX Starlink satellites survive before they deorbit?

Like most Low Earth Orbits (LEOs), the Starlink satellites will eventually have their orbits decay and burn up in the Earth's atmosphere. How long, on average, will this take? I am assuming that there ...
Starship - On Strike's user avatar
4 votes
1 answer
100 views

Draper Labs' Control Moment Gyroscope Spacesuit

Back in 2013/2014 Draper Laboratory announced that they were designing and testing a "spacesuit jetpack" that employed control moment gyroscopes (CMG) to allow astronauts to preform EVAs ...
Jonathan L.'s user avatar
5 votes
2 answers
550 views

Is there any orbital launcher capable of removing the second stage from orbit after inserting the payload satellite into LEO?

The Space Shuttle was able to place a satellite into orbit and to return to Earth. Is there any second stage that may deliver the payload satellite into LEO and do a deorbit burn after that using its ...
Uwe's user avatar
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Repeat ground track with 1 day repetition

I'm struggling with a doubt regarding repeating ground tracks (RGT). I've a satellite in a LEO circular orbit with a predefined non-polar inclination (64°) and I want to determine the needed semi-...
Chicca's user avatar
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