Subscribe to our free daily newsletters
. 24/7 Space News .

Subscribe to our free daily newsletters

Searching For The Grandest Asteroid Tour

Ida and its small satellite Dactyl are main belt asteroids located between Mars and Jupiter. Image credit: NASA/JPL
by Staff Writers
Pasadena CA (SPX) Apr 05, 2007
Asteroids are Earth's closest celestial neighbors, sometimes passing closer to Earth than even the Moon. And yet, to date, only two spacecraft have ever remained in proximity to one of these bodies. Last month, orbit mechanics experts from around the world met to discuss methods for finding the best possible spacecraft trajectory, or flight path, for visiting a sequence of asteroids. The gathering was part of the second Global Trajectory Optimisation Competition, organized by JPL.

The idea of an asteroid grand tour is a celestial analogue to the Grand Tour embarked upon by Renaissance travelers seeking to further their cultural knowledge of Europe. Just as the traveler had to judge carefully which cities to visit based on his or her available resources, so must designers of a spacecraft flight path contend with limited resources and constraints. Such restrictions include the rocket's ability to launch the spacecraft into space, the strength of the spacecraft's thruster, orbital positions of the various asteroids over time, and the spacecraft's longevity.

Determining the best possible trajectory within these constraints, out of the many good ones, is not a trivial matter. It requires a big-picture, or global, view of all the possibilities, that is, it requires global optimization. There are many possible approaches, each with its own strengths and weaknesses.

The inspiration for this problem was the need to study closely different types of asteroids. By visiting a member of each of four different asteroid groups, a spacecraft would provide insights into their chemical composition, their structural characteristics, how they formed, and which might be suitable for future space mining operations. Such insights would also be critical should the need ever arise to deflect an asteroid that is found to be on an Earth-threatening trajectory.

The problem posed by JPL's Outer Planets Mission Analysis Group for the second competition was to design a flight path for visiting four asteroids-- one from each group -- in the shortest amount of flight time and with the least amount of propellant. With almost 1,000 asteroids to choose from, more than 41 billion asteroid sequences could be considered. That's far too many to study individually in the short time allocated for the competition, even with the fastest computers, largest computer clusters and best algorithms.

Fourteen teams - from Europe, Russia, China and the U.S. - sought the elusive best possible trajectory. Their search took place over a period of four weeks late last year, at the end of which they submitted their top solution to be ranked against those of the other teams.

The winning trajectory was found by a team from the Polytechnic of Turin, Italy. Two professors, Lorenzo Casalino and Guido Colasurdo, along with Ph.D. student Matteo Rosa Sentinella and graduate student Francesco Cacciatore, successfully and quickly screened out billions of possible asteroid sequences to focus on the most practical ones. Their winning trajectory, involving visits of four different asteroids in just over nine years, was followed by trajectories from a Russian team (the Moscow Aviation Institute and the Khrunichev State Research and Production Space Center), and a team from the European Space Agency's Advanced Concepts Team.

The workshop where the various teams convened for their discussions took place in Sedona, Ariz., in conjunction with the Space Flight Mechanics Meeting of the American Astronautical Society and the American Institute of Aeronautics and Astronautics.

Did the competition yield the best possible trajectory? With such complexity, it is likely impossible to say, but an educated guess, and the insights gained by comparing the various teams' methods, would suggest that there is still some room for improvement. The Turin team, as winners of this year's competition, will now be organizing the Third Global Trajectory Optimisation Competition, where various teams will again have the opportunity to test their mettle in solving the most challenging problems currently faced by spacecraft trajectory designers.

The Global Trajectory Optimisation Competition was instituted in 2005 by Dario Izzo of the European Space Agency's Advanced Concepts Team. As winners of the first competition, the JPL team organized this latest one, with support from NASA's In-Space Propulsion Program.

Email This Article

Related Links
Near-Earth Object Program
The Iron and Ice Of Our Solar System

Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

Amateur And Professionals Astronomers Combine Observations To Produce Double Asteroid Image
Berkeley CA (SPX) Mar 30, 2007
Roping together observations from the world's largest telescopes as well as the small instrument of a local backyard amateur, astronomers have assembled the most complete picture yet of a pair of asteroids whirling around one another in a perpetual pas de deux.

  • Aurora Space Exploration Program Could See Take Off In May
  • Call For Removal Of NASA Inspector General
  • Cofounders Are Headed to Space
  • NASA Medical Review Team Appointed

  • MARSIS Radar Estimates The Volume Of Water In The South Pole Of Mars
  • ESA Prepares For A Human Mission To Mars
  • Spirit Studies Rocks in Vicinity Of Home Plate
  • NAU Researchers Find Possible Caves On Mars

  • Arianespace To Launch Two Intelsat Payloads
  • Progress On The Sea Launch Investigation And Recovery
  • Two New Payloads For Ariane 5
  • Proton-M Carrier With Canadian Satellite To Be Launched April 10

  • USGS Defines Roles For New Satellite Mission
  • ESA Signs Arrangement With New Zealand On Tracking Station
  • DMCii To Launch New Higher-Resolution Satellite Imaging Service
  • First Greenhouse Gas Animations Produced Using Envisat SCIAMACHY Data

  • Rosetta And New Horizons Watch Jupiter In Joint Campaign
  • New Horizons Shows Off Its Color Camera In Io Image
  • Alice Views Jupiter And Io
  • A Look From LEISA

  • Hubble's View Of Barred Spiral Galaxy NGC 1672
  • Chandra Sheds Light On Galaxy Collision
  • Meteorites Contain Solar System Clues
  • Elusive Oxygen Molecule Finally Discovered In Interstellar Space By The Odin Satellite

  • Shanghai Vies To Win Battle Of Moon Rovers
  • A Piggyback Solution For Science Versus Exploration
  • Assembling Of Moon Mission Spacecraft Begins
  • Dust-Busting Lunar Style

  • Glonass System To Be Launched By Year-End
  • Haicom Is Proudly Announce The New HI-601VT GPS GSM Real-Time Tracker
  • Comtech To Supply Movement Tracking Systems To US Army
  • Russia Allocates $380 Million For Glonass In 2007

  • The content herein, unless otherwise known to be public domain, are Copyright 1995-2006 - SpaceDaily.AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA PortalReports are copyright European Space Agency. All NASA sourced material is public domain. Additionalcopyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement