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Questions tagged [station-keeping]

Operations done to keep a spacecraft in a particular orbit. Generally done by by thruster burns. In LEO this must be done to counteract the momentum loss to atmospheric drag. In other orbits it may be needed to maintain a planned relative position over a long period of time.

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Since L2 has no visible marker, how will James Webb's ground control determine its relative position and velocity for station keeping?

James Webb will be in a halo orbit, station keeping around the Sun-Earth L2 point. This means it needs to monitor its position with regard to L2, for periodic station keeping purposes. But L2 isn't an ...
Stilez's user avatar
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Why does NASA intentionally spin space probes?

In several NASA animations of missions, I've noticed that the spacecraft is rotating while traveling in deep space. This was true of Curiosity when that video came out. Now the Juno mission ...
AlanSE's user avatar
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James Webb telescope; limits to propellant lifetime?

There is a comprehensive article on Wikipedia on the James Webb telescope. It includes a statement regarding the operational lifetime being nominally five years and optimistically ten years. However ...
Roger Wood's user avatar
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Is this what station keeping maneuvers look like, or just glitches in data? (SOHO via Horizons)

I've been enjoying the JPL Horizons web interface and after I discovered the incredibly extensive database associated with SOHO (Solar and Heliospheric Observatory, also see sohowww.nascom.nasa.gov) ...
uhoh's user avatar
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Halo vs Lissajous orbit: Which station-keeping strategy to select and when?

I'm looking for a comprehensive pros and cons of the two most commonly used station-keeping types of orbits used at libration points, Lissajous and halo orbits. When would one select one over the ...
TildalWave's user avatar
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Could JWST stay at L2 "forever"?

Using only reaction wheels powered by solar panel and the sunshield as a sail (in continuous active attitude control) to generate thrust from solar photon pressure in the desired direction, could JWST ...
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3 answers
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What propulsion methods does the ISS use for station-keeping?

The International Space Station is constantly losing orbital energy due to atmospheric drag. How does station-keeping work for the ISS? What sort of propulsion system is used to keep it in the desired ...
Stu's user avatar
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Why is the US building a Lunar Orbital Platform-Gateway (LOP-G)?

An excerpt taken from the Wikipedia page on LOP-G says space-experts have criticized it: The Deep Space Gateway has received criticisms [...] for lacking a proper scientific goal. Former NASA ...
Magic Octopus Urn's user avatar
15 votes
1 answer
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Do we sufficiently understand mechanics of Lagrange point stationkeeping for EML2 rendezvous and assembly?

I've been watching some recorded videos from the April 22 - 24, 2014 Humans2Mars conference (videos and live streams, when available, are on the National Institute of Aerospace channel on Livestream), ...
TildalWave's user avatar
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What kind of thrusters will the James Webb Space Telescope use for station keeping?

Question is fairly self-explanatory, but I couldn't find an answer on Google. I would expect ion thrusters because of their efficiency. Thanks!
Peter's user avatar
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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
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Are any Earth orbits in continual shadow of the Earth?

Do any orbits around Earth leave the spacecraft in permanent shadow? If not, what is the minimum amount of time that a spacecraft must be exposed to sunlight on average?
Slarty's user avatar
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Can solar sail prevent orbital decay?

I can imagine a satellite with a solar sail it rolls when on the night side of Earth, then unrolls near "afternoon", propelled on each past of its "sunset side" of travel. Would such system be a ...
SF.'s user avatar
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Xenon vs Hydrazine, "Should I Stay or Should I go?" Dawn mission decisions

edit 2: There seems to have been some announcement/extension by NASA (20-Oct-2017), possibly this will shed more light on the issues in this question. edit 1: Several months have passed since this ...
uhoh's user avatar
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How can just making the ground broadcast stronger neutralize a zombie(sat)?

In April of 2010 the Geo-not-so-stationary satellite Galaxy-15 stopped responding to ground commands. It operates as a "bent-pipe" or Transponder system, which means - roughly speaking - it will ...
uhoh's user avatar
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Are there any proposals to vacuum up gases in orbit for use as propellant?

Space stations like the ISS orbit at an elevation that puts them squarely in the Thermosphere, and while this has extremely rarefied gas (which is probably more accurately a plasma at many times), it ...
AlanSE's user avatar
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Why do GPS (but not GLONASS or Beidou) satellites have increasing eccentricity over time?

When comparing GPS, Beidou, Galileo, GLONASS, and potentially other GNSS, we can see that the eccentricities of GPS spacecraft are increasing with time (i.e. apogees increasing and perigees decreasing)...
costrom's user avatar
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11 votes
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Do operating GPS satellites ever make orbital maneuvers for station-keeping?

Since GPS satellites need to face the Earth, they might execute momentum-unloading from time to time using pairs thrusters so as to produce torque but minimal change in the orbit, but I am guessing ...
uhoh's user avatar
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10 votes
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How much "wobble" does a typical geostationary satellite experience?

Recall that geostationary satellites are placed into an orbit which is designed to stay above a fixed point on the Earth's surface. If the Earth and the satellite were both spherical cows in an ...
senshin's user avatar
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The design of the halo orbit of the James Webb Space Telescope

As I feel a little less uncomfortable with "halo" orbits, with this question, I would like to explore the practical aspects, in particular those related to the design of the James Webb Space ...
Ng Ph's user avatar
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Are there propellant-less ways to balance at an unstable orbital point?

A station situated somewhere like EML-2 is really at an unstable point. I've heard of crafts using rocket firing to maintain that position in response to small deviations. Could you do this without ...
AlanSE's user avatar
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9 votes
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856 views

How do stable equilibrium points work in GEO? If all geosynchronous spacecraft suddenly lost stationkeeping, would most "fall into" one or the other?

The (currently unanswered) question Quantitatively, how deep are the stable equilibrium points in GEO? How much delta-v to move from one to the other? (also see comments at Delta-v to move from GEO to ...
uhoh's user avatar
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Moon orbit station-keeping delta-V budget

I am looking for examples of station-keeping delta-V budgets from lunar orbiters to verify the results of an orbital-perturbations programm that I wrote for my master thesis. Any indication on where ...
tvoirand's user avatar
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1 answer
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Are there any man-made satellites at Lagrangian points?

There are 5 lagrangian points. Are there any man-made satellites at any of those points? Is there a reason for the presence or absence of satellites at these points?
Dale's user avatar
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7 votes
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What size are the typical keep-inside boxes of geostationary telco satellites?

Geo sats need station-keeping and the size of their keep-inside box is a design parameter. A smaller box implies more manoeuvres to stay inside the box. All depending on the various orbit ...
Bash Frank's user avatar
6 votes
2 answers
1k views

How frequent are (or will be) JWST station keeping burns at L2?

Does anyone have solid information regarding the scheduled/anticipated station keeping burns for JWST at L2? In an online video I've heard mention of 'every 21 days' which at first look seems ...
BradV's user avatar
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6 votes
1 answer
822 views

Why are 22N and 440N liquid engines quite common?

One can often spot that liquid apogee engines are 440 N and attitude control systems are 22 N. Is there a reason why the thrusts are proportional? If the engines are scaled for reducing development ...
karthikeyan's user avatar
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6 votes
2 answers
426 views

What orbit would a space station need to stay in orbit for N years?

(posted before on physics stackexchange but was told to come here) I'm reading this book which has a post-apocalyptic setting. At one point you look at the earth from the view of a 1000-year-old ...
C. McCracken's user avatar
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1 answer
983 views

Will the ISS have electric propulsion to maintain altitude? Is there enough power for it?

In April 2014 this comment was made below the question What propulsion methods does the ISS use for station-keeping?: In November they said in three years, so perhaps late 2016. Since such claims ...
uhoh's user avatar
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6 votes
1 answer
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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 ...
penGuinKeeper's user avatar
6 votes
1 answer
891 views

How much fuel did JWST save due to an accurate launch, and how much will remain after L2 orbit?

How much fuel did JWST save due to an accurate Arianne 5 launch, and how much fuel will be remaining after JWST L2 orbital insertion? And how many years is that fuel expected to last? According to ...
Sheldon's user avatar
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5 votes
1 answer
299 views

Has JWST done its first station keeping yet?

Has JWST done its first station keeping yet? The last burn I know about was the MCC2 burn on Jan24; more than 21 days ago; and that was a pretty long burn with a $\Delta v$ of 1.6 m/sec or 160 cm/sec, ...
Sheldon's user avatar
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5 votes
1 answer
689 views

Station Keeping East-West Maneuver

A GEO satellite spends 14 days in longitude deadband (+/-0.067 deg). At the 14th day, I want to perform an east-west maneuver. But I am uncertain what time I should perform the maneuver at the 14th ...
Elisa Fitri's user avatar
5 votes
0 answers
437 views

Is JWST actually in a Lissajous orbit? What will it look like? Implications for station-keeping?

Note: for lots of great background related to this question, see lagrangian points - The design of the halo orbit of the James Webb Space Telescope - Space Exploration Stack Exchange There are ...
nealmcb's user avatar
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4 votes
1 answer
376 views

Could a ball of water stay in orbit?

Could a water bubble (spherical occlusion of water in air or vacuum) similar to the one in the picture below remain in Earth orbit without evaporating, dispersing, or disintegrating? Assume the orbit ...
Muze's user avatar
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4 votes
1 answer
3k views

How much Delta-V is needed for Orbital Maintenance?

My question is aimed at understanding the how much Delta-V is needed for orbital maintenance in different orbits. Obviously, there still is some residual air resistance that decreases as the orbital ...
HardcoreBro's user avatar
4 votes
1 answer
265 views

How did DSCOVR use its ten thrusters for the long burn maneuvers MCC and LOI?

From this answer to my previous DSCOVR question, and this and this and this article, it seems that DSCOVR used one or more of its ten thrusters for the long burns for mid course correction (MCC) and ...
uhoh's user avatar
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4 votes
1 answer
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Exoplanet orbitable in permanent umbra?

Does any planet, or Kuiper Belt Object, or exoplanet measured or surmised, orbit its star either fast enough, or slow enough and thus distantly enough to cast a long enough shadow, for a spacecraft to ...
Camille Goudeseune's user avatar
4 votes
1 answer
575 views

What is the Distinction between DSCOVR's "engines" and "thrusters"?

I am reading this article about DSCOVR which links (ref 16) to this: DSCOVR: Mission Success for Moog Engines Over a Decade Later , about the recertification by MOOG of the MONARC 5N monopropellant ...
uhoh's user avatar
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4 votes
1 answer
143 views

How satellite orbital vacancies are determined?

Before a new satellite is launched, its desired orbital altitude, inclination is determined. Now with thousands of satellites already in orbit at different altitudes, how do we know if our desired ...
ivric's user avatar
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4 votes
1 answer
634 views

What factors would make station-keeping of an Areostationary Mars satellite necessary?

This answer introduced me to the word Areostationary Orbit - (hint, comes from Ares), an orbit that would remain stationary above a point on the equator of Mars. The article mentions that ...
uhoh's user avatar
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4 votes
1 answer
128 views

How much margin does JWST have for station keeping in Halo orbit?

How much margin in $\frac{m}{s}$ does JWST have for station keeping in Halo orbit? JWST must always stay on the earth side of the L2 saddle since thrusters only point towards the sun. Also` solar ...
Sheldon's user avatar
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4 votes
1 answer
388 views

Station-keeping delta-v per year for an Earth-Moon vanilla halo orbit?

This answer reminds us that an Earth-Moon L1 or L2 vanilla1 halo orbit remaining always visible to some patch on the Moon's surface requires station-keeping. Queqiao uses such an orbit having ...
uhoh's user avatar
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4 votes
0 answers
262 views

extreme longevity of geostationary orbits

I was speculating that geostationary satellites could be around possibly for billions of years (i.e. much beyond the point where plate tectonics would have erased all traces of human civilization on ...
Roger Wood's user avatar
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3 votes
2 answers
194 views

Spacecraft remaining at station-keeping with respect to the ISS

If any spacecraft has remained at station-keeping with respect to the ISS for 12 hours or more, how far from the station did the craft remain?
Bob516's user avatar
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3 votes
1 answer
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The Earth's rotation does change by small amounts; what is done to keep geostationary satellites aligned with ground stations? [duplicate]

Are satellites moved to keep them aligned? Are they at risk of becoming unusable from the small, but measurable changes to Earth's rotation?
Ken Fabian's user avatar
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3 votes
1 answer
923 views

How do RAAN steering increase the launch window?

In the recent ULA video by Tory Bruno Tory Talk // Atlas V Lucy: RAAN Steering (linked below) he gave some short hints about RAAN steering. What is RAAN (Right Ascension of Ascending Node) steering? ...
Auberron's user avatar
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3 votes
1 answer
689 views

How to calculate the change in inclination due to perturbations?

I would like to know the how much the inclination for a generic elliptical orbit changes over an unspecified period. The variation of inclination fluctuates as per a thread listed at the bottom. I'd ...
Capeboom's user avatar
  • 283
3 votes
1 answer
506 views

Delta-V for station keeping

How can I calculate the necessary thrust to keep a satellite of 1 kg mass in orbit, for a Delta-V of 2 m/s, knowing that the correction force must be done once a month for 900 seconds?
Ricardo Casimiro's user avatar
3 votes
1 answer
140 views

Tesseral Part of the Geopotential

I am working on the design of a constellation for academic purposes. I try to describe a phenomenon that appears in the simulations by means of analytic expression and I can't really find a good ...
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