Questions tagged [orbital-maneuver]

In spaceflight, an orbital maneuver is the use of propulsion systems to change the orbit of a spacecraft.

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How could a 90 m/s delta-v be enough to commit the space shuttle to landing?

Wikipedia claims (although with no citation) that in order to make the space shuttle land, an initial powered delta-v of 322 km/h was applied in orbit, retrograde to the shuttle's orbit. 322 km/h is ...
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How can I intuitively understand gravity assists?

For example: How should a spacecraft pass the Moon to reach escape velocity from Earth? How should it pass Venus for a slingshot towards Jupiter orbit? Conversely, to descend Venus to Mercury? Is ...
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Why should space probes have to orbit the Earth before being launched at other planets?

I'm curious to know why any satellites that need to be sent to other planets should be moving around the Earth rather than directly going towards their destination? Today, India launched one satellite ...
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JPL Horizons original reference orbit data for Juno - how to retrieve now that it's been updated?

Because of the slow helium valve responses, Juno was not instructed to execute the large delta-v maneuver to drop from the ~53 day orbit to the ~14 day orbit originally scheduled for 2016-Oct-19. I'd ...
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How often does ISS require re-boosting to higher orbit?

I know that ISS, being in low Earth orbit, requires regular boosts. But I can't seem to find information on how often does this happen. Is it done during each resupply mission, only during some of ...
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Can you tack against the sun using a solar sail?

Solar sails are a great, inexpensive way to move out from the sun, if you’re not in a hurry. Ocean going ships are able to tack against the wind, and to move up wind. Could a solar sail gain inbound (...
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What happens to JWST after it runs out of propellant?

JWST will be orbiting L2 which is unstable equilibrium thus will require propellant for station keeping. JWST will carry propellant for 5-10 years. What will happen once it runs out of propellant? ...
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Why would a slow spiral from a C3 of zero take about 2.4 times as much ΔV as an impulsive maneuver?

I just read a fascinating comment that I don't understand. In part it says ...the Oberth effect does not depend on the mass of the object. A slow spiral in to a low orbit from a C3 of zero will ...
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How is space assigned for satellites that follow intersecting orbits?

Assigning slots to different satellites in various polar orbits seems very difficult on account of them passing over the North Pole. This loose intersection seems like the place where mission errors ...
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Unravelling Cassini's “ball of yarn” orbit around Saturn, tabulation of propulsive maneuvers?

The cool GIF on the NASA JPL Cassini resources page All Orbits (2004-2017): The Ball of Yarn is quite beautiful to look at, but it also hints at some beautiful engineering and orbital mechanics as ...
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Delta-V chart mathematics

Could someone explain me the mathematics behind the Delta-V charts one can find on internet such as:                 &...
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When the ISS moves, do the astronauts feel it?

The ISS has thrusters to avoid debris and to combat orbital decay. Do the astronauts feel the station moving? Do they have to hold onto something and it is the same for when they rotate the station ...
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Why did the recent Sirius FM6 launch use such a high inclination?

Earlier today a Proton-M rocket took off, carrying a Sirius FM6 satellite radio payload destined for geosynchronous orbit. Nothing super exciting, Briz-M upper stage for transfer burns and then the ...
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Is a lunar Sun-synchronous orbit possible at the “frozen” inclination of 86°?

I have been considering if it would be possible to place a satellite in a Sun-synchronous orbit in one of the lunar frozen orbits at 86°. According to NASA scientists there are four inclinations for ...
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Spiraling out from circular orbit to escape via low thrust, what is γ (gamma)?

@MarkAdler's comment led me to ask Why would a slow spiral from a C3 of zero take about 2.4 times as much ΔV as an impulsive maneuver? which resulted in this tidy and efficient @MarkAdler answer which ...
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Design of an elliptical transfer orbit

I was working an example in Charles Brown's "Elements of Spacecraft Design" but I can not figure out how the Time of Flight was calculated. Here is the problem Example 6.5. I got the correct answer ...
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Why would Juno's originally planned orbit lowering partially mitigate radiation damage?

I'm trying to understand where Juno will pick up most of the slow, cumulative radiation damage within it's orbit. Currently it is in the higher, 53 day orbit. The original plan was that tomorrow (...
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Is this really Rosetta's orbit around 67P?

From this link I fount the following representation of Rosetta's orbit relative to 67P: A video from ESA depicts a similar orbit. My questions are: is that really the relative orbit? If yes: why ...
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Can I get higher with Space Junk?

There is a whole bunch of space junk; Wikipedia says there are about 19,000 pieces of junk being tracked. With no clouds, solar energy is readily available, so the biggest missing ingredient for ...
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1answer
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Is 45 km unusually close to pass the ISS and deploy a microsatellite without warning?

Eight years ago, on September 27, 2008, the Shenzhou-7 carying three taikonauts deployed the microsatellite Banxing-1 for testing maneuvers and external imaging. A few hours later at 15:07 UTC the ...
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How to intuitively explain that reaching geostationary orbits consume more Delta V than escape orbits?

Studying again orbital maneuvers, I found the following plotting the cost of a Hohmman transfer between coplanar circular orbits (black line), in terms of $\Delta V$ against the orbit ratio $r_f/r_i$. ...
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How would a Jupiter flyby have helped to get to the Sun? Why was it later ruled out?

The quote below surprised me. What were the orbital mechanical details of using a Jupiter flyby to get a probe from Earth so close to the Sun? Was a "U-turn" possible; single flyby of Jupiter into a ...
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Could Phobos be brought closer to Mars?

Because Phobos has always the same face turned toward Mars, an electric propulsion system could be placed there to slow down the orbital speed. But what would be the energy needed to supply the force ...
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1answer
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Would lunar flyby be less costly in delta-v than direct change from ISS to Hubble orbits

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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Was Hagoromo's capture into lunar orbit ballistic capture or more propulsive?

Hagoromo was a ~36cm nano satellite that was deployed by Hiten while Hiten was in a highly elliptical orbit around the earth, in 1990. From there, Hagoromo was able to enter into an orbit around the ...
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Is the ideal transfer between two arbitrary planar orbits always a bi-tangential ellipse?

I was reading Hollister David's short paper on bi-tangential transfers. The example he uses is a transfer between a planar circular and an elliptical orbit. I am wondering: Is an ideal, that is, the ...
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How to calculate delta-v required for a planet-to-planet Hohmann transfer?

How do you calculate the delta-v required to do a Hohmann transfer from a circular orbit around one body to a circular orbit around another? I'm assuming you'd need to know the masses of the two ...
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How do orbital boosts affect the structural integrity of the ISS?

I've become curious of this question since my time on KSP, and searches have not rendered much. In the simulator, building large stations even without the micro atmosphere being simulated, can cause ...
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How will the ion thruster powered Dawn spacecraft enter orbit around Ceres?

How is it possible for a ion thruster powered spacecraft like Dawn to decelerate to orbit Ceres? Does it have a secondary engine to accomplish this task?
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Oberth effect for Earth vehicles

I don't understand this and must ask a probably very stoopid question here: The Oberth effect says that a rocket is much more efficient when (and in the orbital direction of) a payload when it ...
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What will be “unique” about upcoming SES-9 GTO transfer profile by SpaceX?

In the SES-9 mission press kit, SpaceX mentions: "Given this mission’s unique GTO profile, a successful landing is not expected." What is considered "unique" about this transfer orbit's profile? ...
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How will Starlink satellites deploy from the fairing and reach their orbits?

Elon Musk posted this picture of the first 60 Starlink satellites packed densely into the fairing of the Falcon scheduled to launch in a few hours. There doesn't appear to be a launcher or ejector to ...
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Can solid rockets be used for flexible burn time by jettisoning them?

Solid rockets have some advantages such as high thrust (good for using the Oberth effect), storability and reliability. The main problem is that they fire all their fuel once in one set way. But ...
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2answers
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Insight mission broken-plane maneuver needed?

Will the Insight cruise stage do a broken-plane maneuver at TCM-2 (or 3), or does the Centaur upper stage have plenty of performance (as I suspect) to directly insert this small s/c into the necessary ...
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Could Earth-lunar flybys be repeated consecutively without the use of propellant?

Ever since a recent orbital mechanics question, lunar flybys have been nagging me in the sense that there is obviously energy available in the system. I'm interested if you could get a repeatable ...
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1answer
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Why would Cassini need to reach 64 degrees inclination before “threading the needle”?

The NY Times article Cassini’s Final Mission: Obliteration says that the Cassini spacecraft will end it's more than a decade long exploration of the Saturn system by raising the inclination of its ...
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Is Cassini's 183rd burn; some kind of engine record?

I've just read that when Cassini makes its first close pass of Saturn's F-ring on December 4, it will be the 183rd engine burn which sounds like a lot for orbital maneuvers using a spacecraft's main ...
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What is the largest delta-v ever produced in space from mechanically stored energy?

The math behind this answer suggests that while the delta-v delivered from hand-throwing an object from the ISS would not produce prompt de-orbit and atmospheric reentry, it would still lower the ...
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Quantitatively, how deep are the stable equilibrium points in GEO? How much delta-v to move from one to the other?

This answer discusses a spacecraft in GEO using a two-impulse (circular → elliptical → circular) raise & lower maneuver to move (phase) itself by 180 degrees in longitude then return to synchrony. ...
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ISS location identification; estimate size and direction of astronaut acceleration puzzler

note: This question addresses the same video and phenomenon described in this answer (which I found after posting this) but here I'm asking for an analysis of the trajectories of the test masses (the ...
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1answer
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What inclination change could the 5th stage Orion 38 motor provide ORS-5 (SensorSat)?

The screen shot and block quote below are from Oribal ATK's Mission Update: Minotaur IV ORS-5 Launch. ORS-5 or "SensorSat" is a technology demonstration for a class of satellites that will sit in LEO ...
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What are “Ohms burns” in the context of Scott Kelly, KSP, and the Space Shuttle?

The Ars Technica video Astronaut Scott Kelly teaches orbital mechanics with Kerbal Space Program (also in YouTube) is a little bit humorous. When Scott Kelley is talking about orbit circularization ...
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Does a mission to Venus orbit require less propellant than a similar mission to Mars?

Gravitational attraction is determined using G (m1m2)/r^2 Which indicates the force is inversely proportional to the square of separation of the bodies Of the terrestrial planets Mercury, Venus, ...
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What prompted Lovell on Apollo 8 to announce “there is a Santa Claus”?

On Apollo 8, following the first trans-Earth injection, when the crew came back into contact with Houston, Lovell said: "Please be informed there is a Santa Claus." (Transcript) Given that Apollo 8 ...
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What are the practical uses of a state transition matrix?

I am studying different dynamical models of relative motion of satellites. In my work, I've always just used a numerical integrator like RK78 to integrate the cartesian system of equations: $\dot{r}=...
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Why rotate the Falcon 9 2nd stage after deployment?

Towards the end of the JCSAT-14 live webcast, after the satellite was deployed, we could see small thrusters firing on the second stage, starting to rotate it: The webcast ended shortly afterwards, ...
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Is a braking maneuver more effective at periapsis?

Although my asking this question now was inspired by this one, it's a question that's occurred to me before in the context of orbital capturing. Another way to put this might be: is there an ...
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Are transfers between two orbits commutative?

Are the propellant mass and transfer time from orbit A to orbit B the same as from orbit B to orbit A, considering low-thrust propulsion? That is, in the case of dealing with Keplerian orbit ...
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860 views

Lowest delta-v maneuver to reverse the direction of a satellite in LEO?

Part of this answer was inspired if I remember correctly from a question about how to reverse the direction of a satellite in LEO with the minimum delta-v. Whether this was the original question or ...
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Specific kind of orbital transfer?

What do you call the kind of transfer that takes an orbiting body from orbiting the planet of the system to orbiting a moon of the system. I am merely looking for the name of this kind of transfer ...