[meteorite-list] sterilizing rovers

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue Sep 14 15:50:40 2004
Message-ID: <200409141950.MAA27485_at_zagami.jpl.nasa.gov>

>
> Hi,
> I am curious as to why no one appears to have any information/comments re
> the sterilzing of interplanetary probes!
> Surely someone on this list must have a thought on this matter!
>
> Ron Baalke... any info?
>

All NASA spacecraft to the planets have planetary protection requirements.
For the Mars rovers, here's the information straight from the MER press kit:


Planetary Protection Requirements

In the study of whether Mars has had environments conducive to
life, precautions are taken against introducing microbes from Earth.
The United States is a signatory to an international treaty that
stipulates that exploration must be conducted in a manner that
avoids harmful contamination of celestial bodies.

The primary strategy for preventing contamination of Mars with
Earth organisms is to be sure that the hardware intended to reach
the planet is clean. Each Mars Exploration Rover spacecraft
complied with requirements to carry a total of no more than 300,000
bacterial spores on any surface from which the spores could get
into the martian environment.

Technicians assembling the spacecraft and preparing them for launch
frequently cleaned surfaces by wiping them with an alcohol solution.
The planetary protection team carefully sampled the surfaces and
performed microbiology tests to demonstrate that each spacecraft
meets requirements for biological cleanliness.

Components tolerant of high temperature, such as the parachute and
thermal blanketing, were heated to 110 C (230 F) or hotter to kill
microbes. The core box of each rover, containing the main computer
and other key electronics, is sealed and vented through
high-efficiency filters that keep any microbes inside. Some
smaller electronics compartments are also isolated in this manner.

Another type of precaution is to be sure that other hardware
doesn't go to Mars accidentally. When the Delta launch vehicle's
third stage separated from the spacecraft, the two objects were
traveling on nearly identical trajectories. To prevent the
possibility of the third stage hitting Mars, that shared course
was deliberately set so that the spacecraft would miss Mars if
not for its first trajectory correction maneuver, about 10 days
later.
Received on Tue 14 Sep 2004 03:50:36 PM PDT