What would happen if the Genesis sample return capsule
was off target and was not going to land where it should?
Accurate targeting to the landing site is not expected
to be a problem, but there are several opportunities
to change the timing or course of reentry events if
Ensuring Accurate Targeting -- Fine-tuning of the trajectory
leading up to the landing starts one month before the
scheduled entry into Earth's atmosphere. From 30 days
until one day prior to Earth entry, there are six opportunities
to adjust the trajectory using the spacecraft's onboard
thrusters. At about the distance of the Moon's orbit
on May 1, 2004, Genesis will fly by the Earth and line
up for its daytime landing in Utah.
The return capsule will be aligned to its proper entry
orientation about six hours before entry. At that time
it will be stabilized for flight into Earth's atmosphere
by increasing its spin rate to approximately 15 rpm.
The capsule will be released two hours later. (Navigation
tracking requirements have been established to ensure
accurate targeting of the capsule. Since the capsule
does not have a propulsion system, there is no way to
abort the entry sequence following its release. In the
unlikely event that the capsule was not correctly targeted
at this juncture, it would not be released.)
In the event of a problem that prevents these targeting
and entry events from taking place, an option exists
before the release of the capsule to make a course change
that would place the entire vehicle into an elliptical
orbit around the Earth of about 24 days' duration. This
would be followed by a second entry attempt.
After the capsule is released, the main spacecraft
will be diverted so it cannot collide with the sample
return capsule. Having completed its mission of carrying
the return capsule and its scientific cargo, the spacecraft
will fire its large thrusters one last time in a "divert
maneuver" that will deliver it into an orbit around
the Sun, just ahead of the Earth.
Large Landing Footprint -- The landing site at the
Utah Test and Training Range is a vast and unoccupied
salt flat controlled by the U.S. Army and Air Force.
The site was chosen because it provides an ample area
to allow for aerodynamic uncertainties and winds that
might affect the direction the capsule travels in the
atmosphere. The landing footprint for the sample return
capsule is about 30 by 84 kilometers (18 by 52 miles).
Will the solar matter Genesis is returning cause
any concern about extraterrestrial materials?
The Genesis sample, consisting of protons and atoms
from the Sun, does not pose any risk to the Earth. On
the basis of recommendations from the National Research
Council's Space Studies Board, the mission has been
given a planetary protection designation of "unrestricted"
Earth return. It is the board's determination that the
sample has no potential for containing life.
Since this mission is named Genesis and will tell
us about the beginning of the solar system, will it
try to prove or disprove the Bible?
The Genesis mission will collect samples of the solar
wind, material flowing outward from the Sun, and return
these samples to Earth. Scientists will be able to compare
the compositions of these samples with known compositions
of the planets and help in the effort to understand
how our solar system and its planets formed. It is not
NASA's role to address theological questions or interpretations,
and Genesis' investigation will be studied as a scientific
question, not a theological one.