However, the dissipation can be inferred recalling that the total gravitational potential energy of the body and the spacecraft at the periapsis is not exactly equal to the total potential energy when the spacecraft is at a point on the arm of hyperbola.
First when at the periapsis, where the spacecraft moves orthogonal to the planetary orbit, dissipation vanishes momentarily.
(b) [v.sub.p]: the velocity of the particle or spacecraft at the periapsis;
(c) [h.sub.p]: the altitude of the periapsis of the trajectory of the particle or spacecraft around the Earth.
Using this system, we can maximize directly any orbital elements or any other dynamical orbital parameters such as, the radius of
periapsis and apoapsis.
Upon arrival at Mars in September 1997, MGS will fire its rocket engine for about 20 minutes to achieve a 48-hour, nearly polar orbit with closest approach (periapsis) 378 kilometers above the Martian surface and extending out to 56,400 km (apoapsis).
By dipping into the atmosphere near periapsis, some orbital energy is robbed through friction.
In most cases they become unstable if the nearest point to Ida's center (periapsis) is under 70 km, and Dactyl either crash-lands or escapes to interplanetary space.
Stable arrangements probably exist, he says, even if Dactyl's periapsis is under 70 km and Ida's density above 3.0 g/[cm.sup.3].
Originally, Magellan's orbital low point (
periapsis) was 289 km, but last September it was dropped to 184 km.
The spacecraft has been directed to travel through the uppermost layers of the Venus atmosphere at
periapsis, producing drag that gradually will drop the apoapsis of Magellan's orbit to about 300 km.
Project managers plan to shrink Magellan's current, highly elliptical orbit to a nearly circular one beginning in mid-May by letting the craft dip into Venus's upper atmosphere at
periapsis, where drag will rob it of orbital energy.
