# 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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### GMAT Lambert problem

I would like to plan a mission in GMAT to a certain asteroid, whose orbit and SPK file I have added in GMAT. However, I don't know how to solve the Lambert problem in it to first find the intersection ...
1 vote
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### Interpreting phasing maneuver results using electric propulsion in GMAT

I'm trying to simulate an anomaly phasing maneuver in three different scenarios using electric propulsion in GMAT. The idea is to use the altitude difference (of ~7-8km) between two spacecrafts to ...
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### Is it possible to have a closed(-ish) natural motion circumnavigation around an eccentric target? If so, what parameters define the NMC orbit?

Natural motion circumnavigation (NMC) is when a chaser spacecraft is set in an orbit similar to a target spacecraft's such that the chaser naturally circumnavigates the target spacecraft as a result ...
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### E/I separation for GEO statellites

Two GEO satellites are being colocated using the E/I separation method. Typically, the eccentricity vector would trace a circular motion with the circle positioned in the first quadrant of the Ex-Ey ...
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### Transfer between elliptical orbits

For circular orbits the most efficient transfer is achieved with a hohmann transfer or a bi-elliptic transfer. But what is the most efficient way to transfer between elliptical orbits? I assume in ...
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### Mean motion as indication for satellite (evasion) maneuvers

I am interested in detecting satellite maneuvers, e.g., to avoid collissions. As far as I understand the best publicly available data comes from TLEs although they have their own problems. What is the ...
16k views

### 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 ...
2k views

### Using Mars' inner moon Phobos as a brake

In case of a StarShip (but it could be any other lander), it would arrive a Mars with minimal fuel remaining and it would need to slowdown for reentry, how can it be slowed down for free? Maybe using ...
214 views

### Is it possible to change a satellite's eccentricity without changing semimajor axis (instantaneous maneuver paradigm)? What else needs to "give"?

I've been wondering whether it's possible to change a satellite's eccentricity without changing its semi-major axis. (I'm assuming instantaneous changes in velocity.) At first I thought that this ...
692 views

### Using GMAT to simulate phasing orbits with finite burns

I'm working on a project which requires me to use GMAT but I'm new to the program (and to asking questions on this website). I'm supposed to send a spacecraft from a known GTO to the Moon. A direct ...
722 views

### Most fuel-efficient deorbit from geostationary

Say a spacecraft in geostationary orbit needs to be deorbited (not very common, but bear with me). How does one decide when and how long should the retrograde burns be, in order to have started with ...
1k views

### At which direction do you apply thrust to perform an inclination change maneuver?

Assume that the vehicle is already at the orbital node. No combined plane changes are included. At which direction is the thrust applied to do an inclination change maneuver? So far, Google hasn't ...
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### How did NASA Conclude that the General Theory of Relativity was not Needed for Earth-Moon Flight Path Computation?

This question is wholly seeking historical evidence and not about physics. It is a follow on from the Physics Stack Exchange question: Could we send a rocket to the Moon without knowledge of general ...
1 vote
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### How to determine the best method for Maneuver Detection?

Some context to my question is after reading Vallado, (Fundamentals of Astrodynamics and Applications 5th edition), Chapter 10.11.1 brushes really quickly on the subject. To quote it, "Most ...
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### How will the RADARSAT Constellation Mission (RCM) satellites achieve their final orbital spacing?

The informative page shows that the RCM satellites are intended to orbit as follows: Sun-synchronous circular orbit (dawn-dusk mission), nominal altitude = 592.7 km, inclination = 97.74º, period ...
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### What Δv is needed to reach LEO from a space elevator?

In two recent questions about space elevators, the topic of reaching non-geostationary orbits came up, particularly the popular Low Earth Orbits. This question is simply about how hard exactly it is ...
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### To go from LEO to LLO describe a Bi-elliptic/Hohmann transfer burn sequence?

Being a newbie, I humbly submit the following question : How to minimize the energy (in terms of delta-v burns) to transfer a mass of 1 metric ton (1000kg) from Very Low Earth Orbit (say 200km above ...
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### What is the delta V required to access a polar lunar orbit?

The general reference figure (I use) for entering a low lunar orbit (polar included) is ~900 m/s, which is roughly what was set out in previous questions. However NASA released this white paper which ...
114 views

### I want to write a program to calculate optimal trajectories, where can I find info on the maths

I want to write a program to calculate the optimal way for a spacecraft with a given engine to reach some body astronomical body with the minimum fuel burn (possibly adding in constraints on time, ...
312 views

### What speed could you achieve by slingshotting around earth from moon?

Imagine Apollo 13 had fuel to burn engines on the way back to earth but instead used earths gravity to accelerate and the slingshot around earth
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### Deorbit ISS vs. Preserve ISS as raw materials for ISM?

Recent news: NASA Seeks Proposals from US Industry for Station Deorbit Spacecraft (ISS) NASA has released a request for proposal from U.S. industry for the U.S. Deorbit Vehicle (USDV), a spacecraft ...
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### How often does a CubeSat leverage its ADCS?

I'm wondering how often an Earth observation-focused CubeSat (6U - 27U) would leverage its onboard Attitude Determination and Control System (ADCS). Would it be employing its ADCS to optimize every ...
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### When you burn retrograde, will you reach periapsis sooner or later?

Say you have two spacecraft in identical orbits. Say at a point after apoapsis and before periapsis one of the spacecraft burns retrograde to lower its periapsis, and the other spacecraft does nothing ...
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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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### Do all artificial satellites have engines?

Novice question. A few days ago I watched a TV documentary about Virgin Orbit’s failed mission earlier this year to send satellites into orbit from Spaceport Cornwall. One of the satellites shown ...
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### In MATLAB, Computing a new TLE/orbit following a delta-v impulse?

I have already worked on this project for a week, and I still can not solve this problem by myself. How can I update data for the SGP4 OrbitPropagator in Matlab's ...
1 vote
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### Circularization of an orbit on gmat

I'm using Gmat to turn to zero the eccentricity of an orbit around Mars with an electric thruster. I modeled the initial orbit, introduced the engine, the tank and the solar arrays and created the ...
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### How do i correctly calculate the ellipse that illustrates the orbit of an object in space based on initial state values (r0, v0, deltat, and mu)

I'm working on a game that has a primary UI showing the solar system in a top-down (earth's north pole being roughly 'up'). And I have a need to show a semi-realistic path of travel for an object ...
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### Are there any studies about "ping pong" cyclers between gas giants?

Imagine arriving at Saturn, jettisoning your passenger cargo, and then utilizing the massive gravitational pull of the gas giant to slingshot back towards Jupiter. Due to the immense mass of these ...
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The plot below shows that most of the SpaceX Starlink satellites have moved from circa 450 km to circa 550 kilometers already, using their krypton-based ion engines. A few, along with four ...
1 vote
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### What do the terms milli-g and microgravity mean? How are they used?

I've seen the terms "milli-g" acceleration and microgravity in many questions and answers here, within the context of spaceflight. Does milli-g refer to accelerations between 0.001 $g_0$ and 1 $g_0$, ...
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### What happens to orbit after a radial burn?

We know from Hohmann or bi-elliptic transfer maneuvers that a burn in the tangential direction of an orbit changes the radius of the orbit. But what happens to an object in orbit, when there is a burn ...
1 vote
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### How heavy is an orbital pogo stick?

Moving people from a A to B in space often requires a significant change in velocity, requiring propellant eating into the mass budget. But most of this propellant is "wasted" in moving a ...
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### What is the relationship between the radius of the Hill sphere and escape velocity?

I'm currently working on a video game that will make use of a heavily simplified patched-conic model of the Solar System. I was wondering about some discrepancies between my own calculations as well ...
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### Why does the point of burn on an orbit stay at a constant altitude?

I am having trouble understanding why the current location you are at in an orbit remains unaffected when performing an orbital maneuver. As an example, if I want to raise the apoapsis of my orbit (...
362 views

### Could this three-thruster spherical spacecraft de-tumble itself with zero final velocity?

@Joshua's answer to What is the minimum number of RCS thrusters capable of stabilizing a satellite against an arbitrary rotation? begins: I know this question is old, but I randomly discovered a ...
116 views

### Eccentricity changes of an orbit during out-of-plane burns

I am learning about Space exploration and I have the following question: Does the eccentricity of the orbit remain unchanged during a manoeuvre that is perpendicular to the orbital plane?
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### How can you calculate a Hohmann transfer orbit but ending at the same orbit with a time difference between orbits?

How can you calculate a Hohmann transfer orbit but ending at the same orbit, just having changed the time?
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### During orbital rendezvous, at what distance and approach velocity does the transition from orbital mechanics to “boating around” occur?

During the intercept (terminal) phase of orbital rendezvous, the intercepting spacecraft must use Proportional Navigation or Orbital Mechanics to develop an intercept course: all that counterintuative ...
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### What is the optimum space junk to target for deorbiting?

The danger posed by space debris depends on the debris' mass, ballistic coefficient and orbit. For a given mass of debris, a single large mass (like an intact dead satellite) poses a much smaller risk ...
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### Are there any proposals for propulsive debris deorbiting which address basic requirements for efficiency?

This illustration shows many of the challenges using propulsive deorbiting: https://www.smithsonianmag.com/air-space-magazine/34_aug2017-cleaning-up-space-junk-180963932 The trust line of the tug is ...
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### Eutelsat 13G and Spacebus NEO's all-electric propulsion

Today, Eutelsat's Hotbird-13G was launched by a Falcon 9 to a "geosynchronous transfer orbit". Deployment was at an altitude of roughly 1100 km. The satellite must reach a geosynchronous ...
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### What is the fuel cost of deorbiting a kilo of space junk?

Removing debris from LEO requires a significant delta-V which most schemes propose to accomplish via rocket propulsion. Source The ratio of launch fuel to payload mass is often given as 9:1 for LOE. ...
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### Does Juno have enough fuel to push itself into a more elliptical orbit reaching out to Himalia? [duplicate]

Does the Juno probe have enough fuel to push itself into a highly elliptical orbit around Jupiter so that its apojove would be at Himalia's orbital distance to study Himalia better? Would a gravity ...
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### Can JWST come in for a pit stop? Is the fuel supply on JWST adequate for a transfer to an Earth Moon libration point to allow repairs?

The James Webb Space Telescope is generally considered to be in an unserviceable location at SEL2. If servicing becomes necessary, is it possible for the JWST to use a low energy heteroclinic transfer ...
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### How would I or who/what could help me find the trajectory of an "Extended Grand Tour" spacecraft, without having to take a long course on the subject?

(As forewarning, the most integral details of this question are bolded.) For context, I have been writing an alternate history involving the accelerated development of spaceflight technology for over ...
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### Commencing atmospheric re-entry

Once a decision is taken to get back home (earth), a spacecraft, I think has two options: 1 - To reduce its speed (by firing the thrusters located in the forward or something similar), so that it is ...
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### How could transfers between SEL1&2 and EML Lagrange points be utilized?

The Earth has 7 Lagrange points nearby since SEL1 and SEL2 (Sun-Earth Lagrange points 1 and 2, respectively) are only between 3 and 5 LD (lunar distances) away from the five EML (Earth-Moon Lagrange) ...