After launch from Kazakhstan on Christmas day 8 years ago, the Hughes 601HP communications satellite failed to execute its final burn, leaving it stranded in an unusable elliptical orbit with an orbit plane far from the equator. "It was a healthy spacecraft in a bad orbit. Mission over," commented Cesar Ocampo, who worked for Hughes at the time but is now an associate professor of aerospace engineering at the University of Texas at Austin. The craft did not have enough fuel on board to bring it back into the proper orbit using standard methods, which are analogous to changing lanes in a traffic circle.
A DARING RESCUE
However, two aerospace engineers outside the company, Edward Belbruno and Rex Ridenoure, came up with the audacious suggestion that saved the mission: they suggested saving fuel by diverting the satellite all the way to the moon and taking advantage of the moon's gravity to bring the satellite back into a usable orbit. Belbruno is editor of the Annals volume, is visiting research collaborator at Princeton University, and president and founder of Innovative Orbital Design, Inc. Currently, Ridenoure is President and CEO of Ecliptic Enterprises Corporation of Pasadena, California.
"The suggestion to Hughes from Belbruno and Ridenoure was key," Ocampo said. "Until then nobody at Hughes had thought of using the moon to rescue this stranded satellite." The actual route to the moon used was different than the one suggested by Belbruno and Ridenoure, but the fundamental idea of having to use the moon's gravity in some capacity was critical.
Ocampo's paper, "Trajectory Analysis for the Lunar Flyby Rescue of AsiaSat-3/HGS-1" is the first published account of the rescue, which received a great deal of attention in the press at the time of the rescue, between April and July 1998. However, publicity from Hughes Spacecraft never acknowledged the contributions of either Ridenoure or Belbruno, a grievous omission that the article seeks to redress.
After the mission plan had been devised and its execution initiated, Ocampo was ordered to seize further communication with Belbruno and Ridenoure and was barred from participating in any external communication activities and presentations made to the public and other organizations.
"This cover up represents a major injustice by a prominent corporation of an historical event, and is a blemish on ethical behavior in the aerospace community," says Belbruno.
NEW USES FOR THE LUNAR FLYBY TRAJECTORY CONCEPT
The rescue mission was the first commercial operation in the vicinity the moon. The free return lunar flyby trajectory concept had also been used as contingency trajectories by NASA's Apollo spacecraft. Ocampo predicts it will soon become more common. The free return lunar fly-by trajectory is especially beneficial in terms of fuel for geostationary bound spacecraft launched from high latitude space ports. Last August, the private space tourism firm Space Adventures, Inc., said it will be offering individuals the chance to fly around the moon and back by the year 2010 using a similar maneuver. (www.spaceadventures.com/media/releases/2005-08/284)
Annals of the New York Academy of Sciences
Published since 1823, the Annals of the New York Academy of Sciences preserve and disseminate the proceedings of important conferences and emerging research. More than 600 academic libraries around the world subscribe to the Annals, which rank among the top two percent of sources cited in scientific publications. The New York Academy of Sciences is an independent, not-for-profit organization committed to advancing science, technology, and society worldwide since 1817. For more information, visit our web site: http://www.nyas.org
New Trends in Astrodynamics & Applications: An International Conference
Volume 1065, Annals of the New York Academy of Sciences (proceedings of a June 2005 conference held at Princeton University)
Edited by Edward Belbruno, Princeton University, Princeton, NJ.
December 2005/471 pages/$135
ISBN 1-57331-631-8 (paper)
For more information about this article, please contact:
Cesar Ocampo, (currently on travel in Colombia until 1/18/2005)
Phone: (in Colombia) (011) 57 315 538 8008
(011) 57 4 260 2302