Download - Gravity Assist Maneuver
-
7/29/2019 Gravity Assist Maneuver
1/13
Interplanetary Mission using
Planetary Gravity AssistManeuver
-
7/29/2019 Gravity Assist Maneuver
2/13
Introduction
One problem with interplanetary travel is that it
takes so long.
The alternative to spending long periods in
heliocentric transfer orbits to reach other planets isto increase speed.
Speed can be increased by expending more fuel,but it can also be increased by use of planetary
gravity assist maneuver.
-
7/29/2019 Gravity Assist Maneuver
3/13
Gravity Assist Maneuver
Also known as planetary flyby trajectory,
slingshot maneuver, swingby trajectory.
Useful in interplanetary missions to obtain a
velocity change without expending propellant.
This free velocity change is provided by the
gravitational field of the flyby planet and can beused to lower the Dv cost of a mission.
-
7/29/2019 Gravity Assist Maneuver
4/13
Gravity Assist Maneuver
This gravity assist technique uses a planets
gravitational field and orbital velocity to slingshota spacecraft, changing its velocity (in magnitude
and direction) with respect to the Sun.
Gravity-assisted velocity changes are not totally
free. Actually, the spacecraft steals velocity from
the planet, causing the planet to speed up or slow
down ever so slightly in its orbit around the Sun.
Gravity assist can also bend the spacecrafts
trajectory.
-
7/29/2019 Gravity Assist Maneuver
5/13
How does Gravity Assist Work?
As a spacecraft enters a planets sphere of
influence, it coasts on a hyperbolic trajectoryaround the planet.
Then, the planet pulls it in the direction of theplanets motion, thus increasing (or decreasing) its
velocity relative to the Sun.
As it leaves the SOI at the far end of the
hyperbolic trajectory, the spacecraft has a new
velocity and direction to take it to another planet.
-
7/29/2019 Gravity Assist Maneuver
6/13
Gravity Assist Maneuver
Spacecraft passing Spacecraft passing
behind a planet in front of a planet
-
7/29/2019 Gravity Assist Maneuver
7/13
Gravity Assist Maneuver
-
7/29/2019 Gravity Assist Maneuver
8/13
Gravity Assist Maneuver
Slingshot referenced to the planet Mars
1 2P PV V
1 12sine
-
7/29/2019 Gravity Assist Maneuver
9/13
Gravity Assist Maneuver
Slingshot referenced to the Sun
out inV V
-
7/29/2019 Gravity Assist Maneuver
10/13
Gravity Assist Maneuver
Slingshots do not change the velocity relative to
the planet.
As the probes velocity has increased its kinetic
energy must have changed relative to the Sun.Energy must be conserved, so this energy must
have come from somewhere. The kinetic energy has
come from the planet, deflecting its orbit by a tinyamount.
-
7/29/2019 Gravity Assist Maneuver
11/13
Gravity Assist Maneuver
Transfer to Jupiter
with a Mars Flyby
-
7/29/2019 Gravity Assist Maneuver
12/13
Gravity Assist Maneuver
Orbit pumping (A gravity assist that changes the
magnitude of a spacecrafts velocity).
Orbit cranking (Using a planets gravity to change
the direction of travel).
-
7/29/2019 Gravity Assist Maneuver
13/13
Reference(s)
Douglas J Hopper, Interplanetary Flight Using the
Planetary Gravity Assist Maneuver, A Project Report.Website:http://www.dept.aoe.vt.edu/~cdhall/courses/mec
h533/Reports92b.pdf
http://www.philsrockets.org.uk/interplanetary.pdf
http://www.faa.gov/other_visit/aviation_industry/designe
es_delegations/designee_types/ame/media/Section%20III.4
.1.6%20Interplanetary%20Travel.pdf
http://www.dept.aoe.vt.edu/~cdhall/courses/mech533/Reports92b.pdfhttp://www.dept.aoe.vt.edu/~cdhall/courses/mech533/Reports92b.pdfhttp://www.philsrockets.org.uk/interplanetary.pdfhttp://www.faa.gov/other_visit/aviation_industry/designees_delegations/designee_types/ame/media/Section%20III.4.1.6%20Interplanetary%20Travel.pdfhttp://www.faa.gov/other_visit/aviation_industry/designees_delegations/designee_types/ame/media/Section%20III.4.1.6%20Interplanetary%20Travel.pdfhttp://www.faa.gov/other_visit/aviation_industry/designees_delegations/designee_types/ame/media/Section%20III.4.1.6%20Interplanetary%20Travel.pdfhttp://www.faa.gov/other_visit/aviation_industry/designees_delegations/designee_types/ame/media/Section%20III.4.1.6%20Interplanetary%20Travel.pdfhttp://www.faa.gov/other_visit/aviation_industry/designees_delegations/designee_types/ame/media/Section%20III.4.1.6%20Interplanetary%20Travel.pdfhttp://www.faa.gov/other_visit/aviation_industry/designees_delegations/designee_types/ame/media/Section%20III.4.1.6%20Interplanetary%20Travel.pdfhttp://www.faa.gov/other_visit/aviation_industry/designees_delegations/designee_types/ame/media/Section%20III.4.1.6%20Interplanetary%20Travel.pdfhttp://www.faa.gov/other_visit/aviation_industry/designees_delegations/designee_types/ame/media/Section%20III.4.1.6%20Interplanetary%20Travel.pdfhttp://www.faa.gov/other_visit/aviation_industry/designees_delegations/designee_types/ame/media/Section%20III.4.1.6%20Interplanetary%20Travel.pdfhttp://www.faa.gov/other_visit/aviation_industry/designees_delegations/designee_types/ame/media/Section%20III.4.1.6%20Interplanetary%20Travel.pdfhttp://www.faa.gov/other_visit/aviation_industry/designees_delegations/designee_types/ame/media/Section%20III.4.1.6%20Interplanetary%20Travel.pdfhttp://www.faa.gov/other_visit/aviation_industry/designees_delegations/designee_types/ame/media/Section%20III.4.1.6%20Interplanetary%20Travel.pdfhttp://www.faa.gov/other_visit/aviation_industry/designees_delegations/designee_types/ame/media/Section%20III.4.1.6%20Interplanetary%20Travel.pdfhttp://www.faa.gov/other_visit/aviation_industry/designees_delegations/designee_types/ame/media/Section%20III.4.1.6%20Interplanetary%20Travel.pdfhttp://www.faa.gov/other_visit/aviation_industry/designees_delegations/designee_types/ame/media/Section%20III.4.1.6%20Interplanetary%20Travel.pdfhttp://www.faa.gov/other_visit/aviation_industry/designees_delegations/designee_types/ame/media/Section%20III.4.1.6%20Interplanetary%20Travel.pdfhttp://www.faa.gov/other_visit/aviation_industry/designees_delegations/designee_types/ame/media/Section%20III.4.1.6%20Interplanetary%20Travel.pdfhttp://www.faa.gov/other_visit/aviation_industry/designees_delegations/designee_types/ame/media/Section%20III.4.1.6%20Interplanetary%20Travel.pdfhttp://www.faa.gov/other_visit/aviation_industry/designees_delegations/designee_types/ame/media/Section%20III.4.1.6%20Interplanetary%20Travel.pdfhttp://www.faa.gov/other_visit/aviation_industry/designees_delegations/designee_types/ame/media/Section%20III.4.1.6%20Interplanetary%20Travel.pdfhttp://www.faa.gov/other_visit/aviation_industry/designees_delegations/designee_types/ame/media/Section%20III.4.1.6%20Interplanetary%20Travel.pdfhttp://www.faa.gov/other_visit/aviation_industry/designees_delegations/designee_types/ame/media/Section%20III.4.1.6%20Interplanetary%20Travel.pdfhttp://www.faa.gov/other_visit/aviation_industry/designees_delegations/designee_types/ame/media/Section%20III.4.1.6%20Interplanetary%20Travel.pdfhttp://www.faa.gov/other_visit/aviation_industry/designees_delegations/designee_types/ame/media/Section%20III.4.1.6%20Interplanetary%20Travel.pdfhttp://www.faa.gov/other_visit/aviation_industry/designees_delegations/designee_types/ame/media/Section%20III.4.1.6%20Interplanetary%20Travel.pdfhttp://www.faa.gov/other_visit/aviation_industry/designees_delegations/designee_types/ame/media/Section%20III.4.1.6%20Interplanetary%20Travel.pdfhttp://www.faa.gov/other_visit/aviation_industry/designees_delegations/designee_types/ame/media/Section%20III.4.1.6%20Interplanetary%20Travel.pdfhttp://www.faa.gov/other_visit/aviation_industry/designees_delegations/designee_types/ame/media/Section%20III.4.1.6%20Interplanetary%20Travel.pdfhttp://www.philsrockets.org.uk/interplanetary.pdfhttp://www.dept.aoe.vt.edu/~cdhall/courses/mech533/Reports92b.pdfhttp://www.dept.aoe.vt.edu/~cdhall/courses/mech533/Reports92b.pdf