Questions tagged [gravity-assist]

Questions regarding the use of an object's gravity to change the velocity of a spaceship.

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54 votes
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Why did Voyager 2 receive a gravitational slowdown (as opposed to a slingshot) at Neptune?

I was actually answering this question today regarding velocities of spacecraft, and it occurred to me I've never really looked at this graph in much detail before: Heliocentric velocity of Voyager 2 ...
marked-down's user avatar
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38 votes
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5k views

What is the feasibility of launching a probe to Sedna?

This dwarf planet reaches perihelion in the summer of 2076. At a distance of 76 au, is it feasible to launch a probe that would reach Sedna in time? With an orbital period of over 11,000 years, this ...
Jerard Puckett's user avatar
36 votes
5 answers
10k views

The dreaded apocalyptic asteroid approaches Earth but lands safely on the Moon at zero relative velocity

An asteroid approaches and the Moon 'catches' it in the same way that a sports player catches a ball - that is to say by matching the velocity of the hand to that of the ball. Could a lucky slingshot ...
chasly - supports Monica's user avatar
36 votes
1 answer
3k views

Why is there currently so little talk about a Venus gravity assist for a crewed Mars mission?

I just came across this video about manned Mars and Venus missions that were planned in the 1960s. They considered a Venus flyby the best way to get humans to Mars. Indeed, there are also modern ...
KarlKastor's user avatar
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29 votes
3 answers
7k views

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 ...
SF.'s user avatar
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28 votes
4 answers
13k views

Could the sun be used as a gravity assist outside the solar system (with current tech)?

I think I might have understood what this XKCD comic is trying to do. The diagram is proposing to use the Oberth effect at closest approach to the sun to escape the solar system! (image license: CC ...
AlanSE's user avatar
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25 votes
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Is there any limit to how many times you can increase velocity by repeated sling shot manoeuvres?

I believe travelling to Alpha Centauri at ~10 km/s would take of the order of 100 000 years (10 km/s is the order of speed of probes currently leaving the solar system). That seems 1. rather a long ...
Raffles's user avatar
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22 votes
4 answers
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Do you need to burn fuel between gravity assists?

If you are planning a mission to an outer planet with multiple gravity assists included, do you need to do some burns for corrections, between the slingshots, or the ideal trajectory is already ...
Teo Stanciu's user avatar
21 votes
4 answers
6k views

Has Luna been used for gravity assist for interplanetary probes?

The Earth's natural satellite has a great deal of angular momentum that seems to me could be used to derive a considerable boost for leaving the local SOI. Has any probe used a Lunar flyby as part of ...
Jerard Puckett's user avatar
19 votes
2 answers
9k views

Why did Voyager 1 lose speed after the sudden gain in speed from gravity assist?

The Voyager 1 lost speed gradually after gaining speed from gravity assist. Is the external thrust applied in the opposite direction to move closer to the planet, or does the spacecraft lose its ...
Auberron's user avatar
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19 votes
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How much delta-v can we squeeze out of a gravitational slingshot and what factors limit it?

A lot of space probes use gravity assists from various space objects to boost their speed and save on propellant requirements. On what factors does the increase of delta-v depend? My guesses are: ...
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18 votes
4 answers
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Can we set up an orbiting transporter between Earth and the Moon?

I will give an example with the moon. If some spacecraft is put either in orbit around both earth and moon or in highly eccentric orbit that intersects with the moon orbit, some other spacecraft can ...
Nikolai Frolov's user avatar
17 votes
2 answers
3k views

How much longer would New Horizons take to reach Pluto without the Jupiter slingshot?

A recent answer by PearsonArtPhoto claims: New Horizons was launched at Solar System Escape Velocity, meaning it could have visited anywhere beyond Earth without stopping. It did visit Jupiter, ...
SF.'s user avatar
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16 votes
8 answers
11k views

Why didn't Voyager 1 and Voyager 2 crash on into Jupiter or Uranus when they approached near to these massive planets?

I was reading about gravity assist and I read that both the Voyagers used gravitational force of these planets to speed up. But I wanted to know why weren't they completely attracted by their ...
Gamira's user avatar
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16 votes
2 answers
4k views

Would an astronaut experience a force during a gravity assist maneuver?

When an astronaut is inside of a ship accelerating (from engine burns), or decelerating (due to reentry) they experience a tug in a relative direction. Suppose an astronaut is in a space ship that is ...
Ezra Bailey's user avatar
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16 votes
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What pushes a spacecraft during a flyby?

xkcd today posted the following graphic: Of these, the only one that I really don't understand is "What pushes a spacecraft during a flyby?" I don't understand why this is an issue. How energy is ...
PearsonArtPhoto's user avatar
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What probe received the most gravitational assists?

Often when launching deep-space probes, scientists will "loop" them around planets, "stealing" some of the planet's momentum and transferring it to the probe - giving the probe a huge speed boost. I'...
user avatar
16 votes
1 answer
1k views

Did the Pluto flyby give New Horizons any significant gravitational boost?

Last week New Horizons passed within 14,000 km of the center of Pluto. I assume this will have put New Horizons within the gravitational influence of Pluto. Pluto's average orbital speed is 4.7 km/s....
Max Q Lagrange's user avatar
16 votes
2 answers
2k views

What software can be used to determine deep-space trajectories?

In What are the choices today for orbital mechanics simulation software?, an entire range of software was listed for many platforms. I'd like to narrow this down a bit. Specifically, two questions: ...
Jerard Puckett's user avatar
16 votes
1 answer
2k views

When are there launch windows to Neptune via Jupiter?

I suppose there's a launch window to Neptune by using Jupiter as often as there are Jupiter/Neptune conjunctions, every 13½ years. But which years are Jupiter and Neptune best aligned for gravity ...
LocalFluff's user avatar
15 votes
3 answers
4k views

Gravity Assist braking

Usually gravity assist maneuvers are used to accelerate a probe without expending propellant. But could gravity assist maneuver be used to brake and insert into orbit? Is there a formula to use for ...
lurscher's user avatar
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15 votes
3 answers
1k views

Gravity assist for manned travel

Since we already use gravity assist to launch satellites through the solar system, is there any way we can use gravity assist to speed up a manned trip to a planet such as Titan or Europa, while also ...
matthew spear's user avatar
13 votes
5 answers
2k views

What's the best flightpath to get to Sedna by 2076?

Repeated Google searches over the past year, as well as recent searches of NTRS, AIAA, and arXiv, show no signs that anyone has seriously considered a mission to Sedna. I would like to propose a ...
Jerard Puckett's user avatar
13 votes
2 answers
3k views

How are gravity assists conceived?

So there are some very complex gravity assists out there. The Cassini mission, for instance, used a VVEJ (Venus Venus Earth Jupiter) gravity assist to make it to Saturn. Similar flybys have been done ...
PearsonArtPhoto's user avatar
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13 votes
1 answer
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What does the BackFlip lunar cycler do in its pass by Earth?

This paper describes an Earth-moon cycler orbit. In this concept, a 180 degree "BackFlip" is used to modify a more simple cycler orbit. However, I can't figure out what cycler orbit it modifies, and ...
AlanSE's user avatar
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11 votes
1 answer
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Good year for start of an interstellar mission, due to gravity-assist

What is the next excellent year for a interstellar mission (beyond Neptune). The main acceleration for those missions are gravity-assists with Jupiter, Saturn, Uranus and Neptune. Voyager 2 managed ...
Mario Krenn's user avatar
10 votes
1 answer
2k views

To what extent could a single Triton flyby slow down a direct Hohmann transfer to Neptune for NOI?

I can't seem to find any good sources online for this, all I get are documents on how Nice model was used to compute Neptune's gravity capture of Triton via a binary dissociation, possibly because of ...
TildalWave's user avatar
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9 votes
3 answers
779 views

Did the spacecrafts Galileo or Juno use the Galilean moons for a gravity assist before entering Jovian orbit?

Galileo and Juno are the only two spacecraft to have entered orbit around Jupiter. Did either of them use one of the Galilean moons for a gravity brake before in order to enter a stable orbit around ...
Jonathan L.'s user avatar
9 votes
3 answers
10k views

How do we come up with the gravity assist (or slingshot) formula?

When you search up in google gravity assist formula, it comes up with the simplest version: Which means that: Final velocity = Initial velocity + 2 (velocity of the planet) Then if we do some more ...
Matthew's user avatar
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9 votes
2 answers
478 views

Could Starman get ejected from the Solar System?

This is not about a prediction of Starman's fate, although it might be interesting to find it so. This is about any object having similar aphelion and perihelion values to Starman (Elon Musk's Tesla ...
Anthony X's user avatar
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9 votes
2 answers
3k views

What is the effect of gravity slingshots around Earth on Earth's rotation and orbit time, and is this effect worth considering?

Several space probes have used gravitational slingshots around Earth as part of their mission plan to get to other places in our solar system. Some examples I could find quickly are Galileo, Messenger ...
user's user avatar
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9 votes
1 answer
488 views

What do the shaded vertical lines in the animation of Gravity assists of space probes, mean?

Example Animations from Wikipedia — https://en.wikipedia.org/wiki/Gravity_assist#/media/File:Animation_of_Voyager_1_trajectory.gif https://en.wikipedia.org/wiki/File:...
Raj Arjit's user avatar
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9 votes
2 answers
1k views

What are the practical limitations of gravitational assists?

Is there any specific, practical reason why we couldn't have a probe swing by Saturn, Uranus, Jupiter multiple times, over and over, before getting hurled into interstellar space at insane speed, ...
SF.'s user avatar
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9 votes
2 answers
831 views

Why Earth flybys?

When playing around with the NASA trajectory browser, I noticed that practically every mission to the Jupiter system followed the mold (order of magnitude of $\Delta V$): Start in Earth Orbit (of ...
mart's user avatar
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9 votes
1 answer
265 views

Which moon is best? (for gravity assists)

Inspired by my answer to Is a ballistic Jovian capture using the Galilean moons possible from interplanetary entry? in which I discovered that Callisto offers a stronger gravity assist than Ganymede ...
BrendanLuke15's user avatar
9 votes
1 answer
1k views

When will 3 outer planets line up for a flyby mission next time?

All 4 outer planets line up once every 175 years. 2 of them line up at least once every orbit Jupiter makes, about every 12 years. But how often do 3 of the outer planets line up? Here's a simple ...
LocalFluff's user avatar
8 votes
2 answers
2k views

What is the smallest body in which a sling shot maneuver can be performed?

This question asks about the smallest sling shot maneuver performed. What was the smallest intentional, acknowledged slingshot maneuver? I'm asking how small of an object be to perform a sling shot ...
Muze's user avatar
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8 votes
1 answer
258 views

Is a graviational slingshot around Mercury a feasible solution for space probes?

Our spacecraft have rarely visited Mercury, for reasons obvious to those who know orbital mechanics. The Mariner 10 visit to Mercury was revolutionary by using Venus for the novel slingshot maneuver, ...
uruiamme's user avatar
  • 183
8 votes
2 answers
1k views

Can New Horizons be turned into an orbiter for the Pluto system?

If the New Horizons team doesn't find a KBO target for the probe, can they turn it into an orbiter for the Pluto system? I know entering orbit right now would be impossible, but would it be possible ...
symbiotech's user avatar
8 votes
1 answer
3k views

Could we use the moon for a slingshot effect?

The slingshot effect or gravity assist maneuver produces a boost on the speed of the object which attempts to approach a planet head-on at a speed V while the planet is moving directly toward us at a ...
Matthew's user avatar
  • 612
8 votes
1 answer
165 views

Would the Oberth effect apply to a rocket powered playground swing?

Would the Oberth effect (as explained as an answer to a gravity assist maneuver) apply to an earthbound partial orbit simulator in a strong gravity field, i.e. a playground swing? Imagine a swing with ...
wistlo's user avatar
  • 361
8 votes
1 answer
362 views

Could Cassini crash land on Mercury?

I saw a news article once that discussed having Cassini use gravity assists to crash land on Mercury to end it's life. Is this even possible, and is there a chance that this could actually happen? Or ...
PearsonArtPhoto's user avatar
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8 votes
1 answer
387 views

Venus gravity assist (and aerobraking) - How much delta-V can it add?

The Voyagers made a grand tour using the gravity assist of each planet. But Jupiter, with a 12 year orbital period, doesn't always line up to be useful for spacecrafts destined to further planets. ...
LocalFluff's user avatar
7 votes
4 answers
324 views

How to place a satellite in retrograde heliocentric orbit?

Imagine a mission which requires a retrograde heliocentric orbit. How could this be achieved? a direct launch would require ridiculous delta-v. There was a similar delta-v problem placing Ulysses in a ...
Woody's user avatar
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7 votes
2 answers
434 views

What are the gravitational assist effects on the inclination of a probe's trajectory, from passing by Jupiter at different latitudes?

A flyby probe at Jupiter gets its inclination, relative to the ecliptic, changed if it passes above or below Jupiter's equator. How sensitive is a trajectory to this effect? I imagine that there ...
LocalFluff's user avatar
7 votes
1 answer
520 views

Will Dragonfly flyby Jupiter en route to Saturn?

The table on the "Exploration of Jupiter" Wikipedia page suggests Dragonfly will be the first mission to the outer planets that will not use a gravity assist from Jupiter. Is there a source confirming ...
Anton Hengst's user avatar
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7 votes
1 answer
529 views

How exactly did Jupiter change Ulysses orbital plane from nearly ecliptic to polar?

Ulysses spacecraft trajectory is truly amazing. Utilizing gravity assist from Jupiter it was sent into polar orbit around the Sun. I can understand gravity assist concept, I can also (intuitively) ...
Sergiy Lenzion's user avatar
7 votes
1 answer
804 views

Is it possible to leave the Solar System by repeatedly using gravity assists from the Earth?

If a spacecraft was accelerated to just above Earth's escape velocity, it would begin orbiting the sun with an orbit very similar to Earth's. Could the spacecraft then repeatedly perform a gravity ...
Thomas's user avatar
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7 votes
1 answer
328 views

Does the Oberth effect motivate complementing ion electric propulsion with chemical rocketry?

The solar electric ion propulsion engine of the Dawn spacecraft to Vesta and Ceres used Mars for gravity assist. Would it be gainful to complement an ion engine with a high thrust (solid) chemical ...
LocalFluff's user avatar
7 votes
1 answer
620 views

How can I look for the best date of launch for gravity assist?

I am new to astrodynamics, and I am trying to learn about gravity assists, but I don't understand how I can easily decide a launch date and arrival late for the planet in which I calculate the gravity ...
Alberto De Celis Romero's user avatar