Questions tagged [gravity-assist]

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

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33
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1answer
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 ...
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50 views

What is the maximal gravity assist boost achievable in the Milky Way galaxy using black holes?

This question on the world building site sparked my curiosity on whether we could see signs of an intergalactic civilization. The question itself effectively asks whether this is possible for our own ...
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2answers
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How will Juice substantially increase its inclination around Jupiter in January 2031?

The ESA video Juice’s Jovian odyssey linked below is quite interesting to watch. Around January of 2031 it substantially increases its inclination around Jupiter. Big inclination changes can be ...
2
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1answer
148 views

How difficult to gravity assist brake on entry to Alpha Centauri system? [duplicate]

Say a generation ship arriving at Alpha Centauri A system wants to get into orbit (or land) on an exoplanet there. After decelerating for the 2nd half of the journey, their approach velocity is still ...
7
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3answers
642 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 ...
8
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1answer
111 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 ...
14
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2answers
3k 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 ...
5
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2answers
286 views

Why is NASA proposing an EMEJ (MEGA) trajectory for Europa Clipper instead of EEJ?

A launch service request was recently put out for Europa Clipper to do a flyby of Mars on its way to Jupiter. How is that a better trajectory than an EEJ, similar to Juno? Launch Vehicle Performance: ...
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1answer
131 views

Could artificial magnets orbiting the sun be used to accelerate spacecraft, like a magnetic “gravity” assist?

Say there's a powerful magnet in an orbit between those of Earth and Mars. Could a spacecraft traveling between those planets save propellant by performing a slingshot maneuver using its magnetic ...
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1answer
62 views

Gravity assist from Jupiter if leaving Callisto?

If I spacecraft was leaving Callisto to return to Earth, would there by any situation where it would use a gravity assist from Jupiter to increase its velocity?
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1answer
53 views

How do space agencies choose arrival dates to planets (i.e. Mercury) from a gravity assist (i.e. Venus)?

Assuming I was looking for arrival opportunities from 2020 to 2030, how can I calculate the possible arrival dates to Mercury given a departure date from a gravity assist from Venus?
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2answers
191 views

Was the gravity assist at Jupiter the most dangerous part of the New Horizons mission?

In terms of success of the mission, was the Jupiter fly-by the time when problems with the flight path was most likely to happen? Was the odds of failure at that point ever studied? If so, what were ...
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2answers
146 views

Is it more efficient to burn all needed fuel in an Oberth manoeuvre at once or burn a fraction of the fuel for each orbit?

I was looking into Parker Solar Probes trajectory and was wondering what would be the most optimal way to utilize a retrograde thrust at perihelion to reduce the number of needed gravity assists. I ...
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3answers
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Speed at aphelion is decreasing for Parker Solar Probe with each new orbit despite being closer to the Sun

Sorry for the really bad picture I am looking at some data from the Parker Solar Probe mission and I was looking at the speeds of PSP at perihelion and aphelion at each new, different, orbit (the ...
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1answer
97 views

Effect of incoming velocity on change in velocity in a gravity assist

In a gravity assist does the incoming velocity of a space craft effect how much speed it gains. For example say a rocket was approaching Jupiter for a gravity assist with speed v and another rocket ...
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1answer
186 views

Why is the highest speed that Voyager 2 achieved from the Jupiter gravity assist not at perijove?

I plotted some data of the speed of Voyager 2 for various times (around the Jupiter flyby) and noticed that the highest speed that Voyager achieved was not at perijove and was wondering why this might ...
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49 views

Where can I find the specific details of a gravity assist space mission?

0 I am writing a research essay where I need to know the specific details of a gravity assist mission such as Voyager 2's flyby of Jupiter for example (but any mission would work as long as it is a ...
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56 views

What is the relationship between the periapsis altitude and the change in velocity in a gravity assist?

In a gravity assist maneuver if I were to decrease the distance from the rocket to the periapsis of the planet it is orbiting (I believe this is called the periapsis altitude but I may be wrong) it ...
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4answers
306 views

Have space probe gone to unplanned destinations?

Reading this question about multiple gravity assists (Why is Voyager 1 faster than all other space probes?), it caused me to wonder if any probes have been redirected to additional (or alternate) ...
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1answer
436 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:...
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1answer
136 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, ...
7
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1answer
471 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 ...
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2answers
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Why does Voyager 1 lose speed after the sudden gain in speed from gravity assist?

The Voyager 1 loses speed gradually after gaining speed from gravity assist. Is the external thrust is applied in the opposite direction to move closer to the planet, or does the spacecraft lose its ...
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1answer
1k views

Rockoon on steroids

In typical rockoon a balloon is the lifting body to the upper atmosphere where a rocket is released and ignited. But I would like to ask about a variation to launch small payloads to space. Instead ...
7
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1answer
299 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) ...
2
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1answer
147 views

Could we reverse gravitational slingshot a fast object to slow it down and capture it in an orbit?

I have heard of plans to capture an asteroid in an orbit around the earth, to have it close by so that we could study it more easily. Such objects can have very high velocities, (I assume) possibly ...
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Free Return Transfer Problem

I'm trying to understand how a free-transfer return works. It makes sense to me conceptually, but putting numbers to it it is unclear. I'm not sure how to obtain information about the transfer ...
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1answer
137 views

What is the fastest velocity to which something can be accellerated using a gravity assist [duplicate]

My understanding of gravity-assists (slingshot) is that they use some of a more-massive object's orbital energy to gain massive acceleration. What's the upper limit on how much velocity an object ...
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2answers
341 views

STK Astrogator Earth Flyby

TLDR: How do you set up an EEV maneuver, specifically, how do you go from an earth orbit to a heliocentric orbit with a periapsis within Venus’s orbit in astrogator? I know the theory but astrogator ...
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History of the planetary flyby for gravitational assist; first conception, mathematical demonstration, plan, and execution?

Planetary flybys for gravitational assists are a stable of deep space missions. When did the following things happen? First documented realization that gravitational assists in spaceflight were ...
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4answers
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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 ...
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96 views

Were there any identified launch windows and gravity-assist trajectories that could put a probe on a “Grand Tour” trajectory around 1981?

For context, I am developing an alternate history that features a far more ambitious Voyager program than the one undertaken in real life. However, despite the increase in NASA funding provided in the ...
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99 views

How to plot conic from Lambert solver

I am trying to solve for an optimal multi-gravity assist trajectory from Earth to Saturn using Matlab. I have already solved for the departure and arrival velocities from and to each planet using a ...
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2answers
144 views

Gravity assist from Mercury

The Oberth effect states most energy can be gained when you have highest velocity in orbit. The interplanetary missions, generally involve ion propulsion along with gravity assist from planets such as ...
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1answer
549 views

Can a “gravity assist” at a black hole accelerate light faster than the speed of light? [closed]

With the help of a gravity assist from a black hole, can light travel faster than its natural light speed?? Satellites use gravity assistance. In a similar way can light traveling near black hole ...
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1answer
194 views

Gravitational keyhole for spacecraft flyby?

Is there a term for the area near a planet a spacecraft must pass through for a gravitational-assist flyby, or does 'gravitational keyhole' apply to gravitational assists as well as for asteroids?
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1answer
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Mangalyaan + Trident; is it possible? escape the solar system using a low cost booster

5 years ago, India launched the Mangalyaan spacecraft to Mars, on a budget that raised eyebrows at the time. It was probably the Mars mission launched with the least powerful rocket; a feat only made ...
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1answer
152 views

Will a spacecraft accelerate in a gravitational field via the use of a powered rotating mass?

I believe that a powered rotating mass on board a spacecraft should result in the spacecraft being propelled in a continuous increasing velocity towards the source of the gravitational field. To help ...
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What Jovian system science targets would be suitable for Jupiter gravity assist flyby missions with other primary purposes?

Flying by Jupiter for gravity assist, and with the Oberth effect bonus, has been used for multiple missions to other outer planets and to comets. And has potential for use even for missions aiming at ...
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2answers
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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 ...
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What was the smallest intentional, acknowledged slingshot maneuver?

I'll keep it short but please read through! Gravitation's $1/r$ potential means everything in the solar system is pulling on everything all the time. Gravitational slingshot maneuvers are normally ...
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3answers
286 views

How fast can an orbit exist in the solar system?

How fast is too fast to stay in orbit around any particular large body in the solar system?
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8answers
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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 ...
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2answers
562 views

How much does a swing-by change the orbit of the planet?

A friend of mine told me that one Voyager swing-by moved the orbit of Jupiter a foot closer to the sun. I understand that Jupiter was slowed by the gravity assist, but I figured it would be minuscule ...
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0answers
161 views

Determining the spacecraft position vector with respect to ICRF frame for Venus flyby

For an interplanetary mission design to Saturn, I have considered doing multiple gravity assists starting with Venus. I am using the JPL Horizons ephemeris and ESA Lambert Solver. I have the ...
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1answer
92 views

Perpetual motion [closed]

When I was young, I had a set of bar magnets which had poles on the side faces (across the thickness) and not at the two ends. I placed one on the table facing one pole upwards (say north pole). ...
6
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1answer
195 views

Help choosing a gravity assist scenario for this problem

The problem stated below is from an assignment I was given. My initial approach involved doing a direct Hohmann Transfer to Saturn. This approach violated the fuel constraints and hence was deemed ...
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5answers
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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 ...
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0answers
150 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. ...
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106 views

Multiple gravity assists [closed]

Is it possible,just by looking at the heliocentric position and velocity vectors of the spacecraft and the planet,to decide whether the resulting flyby would be trailing or a leading flyby? If yes, ...