They left out the most important part. How to use it to time travel. ..
The Juno spacecraft is going to get a gravity assist from earth in about 11 more days.
http://www.nasa.gov/mission_pages/juno/main/index.html#.UkdBtFMW5kh
So basically it is using a warp in space?
Many years ago a friend of mine helped use this exact technique from White Sands to salvage a Com Satellite that was improperly positioned on launch.
They scrubbed the civilian portion of the mission and used the positioning rockets & planetary positioning to put it in the correct orbit for the military application. Successfully.
Bookmark.
From Wikipedia:
MESSENGER
The MESSENGER mission (launched in August 2004) made extensive use of gravity assists to slow its speed before orbiting Mercury. The MESSENGER mission included one flyby of Earth, two flybys of Venus, and three flybys of Mercury before finally arriving at Mercury in March 2011 with a velocity low enough to permit orbit insertion with available fuel. Although the flybys are primarily orbital maneuvers, each provided an opportunity for significant scientific observations.
The Cassini probe – multiple gravity assists
The Cassini probe passed by Venus twice, then Earth, and finally Jupiter on the way to Saturn. The 6.7-year transit was slightly longer than the six years needed for a Hohmann transfer, but cut the extra velocity (delta-v) needed to about 2 km/s, so that the large and heavy Cassini probe was able to reach Saturn, which would not have been possible in a direct transfer even with the Titan IV, the largest launch vehicle available at the time. A Hohmann transfer to Saturn would require a total of 15.7 km/s delta-v (disregarding Earth's and Saturn's own gravity wells, and disregarding aerobraking), which is not within the capabilities of current launch vehicles and spacecraft propulsion systems.
Anyone that ever watched the roller derby with Dick Lane in the 50’s and 60’s knows how the sling shot works to get the jammer in the position to score big points