Genesis Gets to the Point
NASA’s Genesis spacecraft will begin its primary science
mission of collecting particles from the solar wind when it
begins to orbit a point between the Sun and Earth on Friday,
Nov. 16.
Engineers will send a final command to the spacecraft at
11:03 a.m. Pacific time (1903 Universal time) to begin
operating its hydrazine thrusters for about 267 seconds. This
will put the spacecraft into its final orbit at 1908 Universal
time (11:08 a.m. PST) to begin the particle-gathering phase of
the mission. The orbit is at a point where the gravity of
Earth and the Sun are balanced. This is called the Lagrange
point, or L1.
“This is a crucial maneuver for Genesis, since it sets up
the five-loop halo orbit around L1 in which we gather the
solar wind samples,” said project manager Chester Sasaki of
NASA’s Jet Propulsion Laboratory, Pasadena, Calif., which
manages the mission. The mission is designed to help
scientists understand how our solar system formed.
After mission managers check to make sure Genesis has
successfully entered orbit, they will begin to prepare for the
spacecraft’s main goal: collecting solar wind samples.
L1 is an ideal location for Genesis’ studies, since it
affords an uninterrupted view of the Sun and is beyond Earth’s
magnetosphere, which disrupts the solar wind. Genesis will
expend very little propellant to stay in orbit, since the
forces of the Sun, Earth and the spacecraft are carefully
balanced in its orbit around the point.
The mission’s planners have built-in maneuvers to
maintain the spacecraft in its orbit around the Lagrange
point. If Genesis’ injection into orbit goes as planned, the
next maneuvers will be very small. On Nov. 30, the sample
return capsule will be opened, and a few days later Genesis
will open its inner canister, extend its collector arrays and
begin collecting concentrated ions.
Genesis will fly in a path nicknamed “the lazy eight”: a
flight path that resembles a well-formed potato chip. Genesis
heads to the L1 point 1.5 million kilometers (930,000 miles)
from Earth, and orbits there for 29 months. On its return, the
spacecraft swoops past Earth and around another Lagrange
point, L2, a mirror image of L1 on the opposite side of Earth,
to position itself to enter Earth’s atmosphere and return its
precious cargo of solar wind samples in August 2004.
JPL manages the Genesis mission for NASA’s Office of
Space Science, Washington, D.C. Lockheed Martin Astronautics,
Denver, Colo., and Los Alamos National Laboratory, N. M.,
operate the mission jointly with JPL. JPL is a division of the
California Institute of Technology, the home institute of the
principal investigator, Dr. Donald Burnett.
More information on the Genesis mission can be found at
http://genesismission.jpl.nasa.gov .
