A mathematical formulation (MGA-1DSM), which parameterizes a generic interplanetary trajectory as a sequence of legs containing a gravity assist
and one deep-space maneuver, is outlined, leading to the purposeful definition of a global optimization problem.
The Earth flyby gravity assist
increases the spacecraft's speed relative to the Sun from 78,000 miles (126,000 kilometers) per hour to 87,000 miles (140,000 kilometers) per hour.
In performing its first deep-space maneuver, the spacecraft initiated the first of two planned firings of its main engine to refine the spacecraft's trajectory, setting the stage for a gravity assist
from a flyby of Earth Oct 9, 2013, that will send it on its way for arrival at Jupiter July 4, 2016, NASA Jet Propulsion Laboratory in Pasadena, Calif., was quoted as saying by the United Press International (UPI).
In an audacious venture using gravity assist
at Earth and libration orbiting for two years near L1, the Genesis mission, launched by a Delta II in 2001, in 2004 returned a capsule to Earth bearing actual samples of the solar wind and interplanetary medium embedded in ultraclean collector plates.
The gravitational fields of these planets will pull on the spacecraft as it passes them, causing it to increase its speed, a phenomenon called gravity assist
. NASA engineers liken gravity assist
to a person running next to a merry-go-round.
The spacecraft passed about 8,000 kilometers from the Moon on Thursday, which provided a gravity assist
that helped TESS sail toward its final working orbit, the US space agency said on Friday.
That data collection, which included study of the moon as well, began four hours after the gravity assist
 discuss the planning of trajectories to Neptune using a variety of gravity assist
maneuver schemes, highlighting the difficulty in finding an optimized solution with so many combinations of the planets considered.
Caption: Juno snapped this photo of Earth when it came close for a gravity assist
on October 9, 2013.
After the Mars gravity assist
, Rosetta's perihelion will drop until it reaches the orbit of Venus, but before the probe comes that close to the Sun, another Earth flyby will send it out of the ecliptic plane.