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STANFORD UNIVERSITY MEDICAL CENTER
STANFORD, CALIFORNIA 94305 e (415) 321-1200

STANFORD UNIVERSITY SCHOOL OF MEDICINE November 4, 1969
Debariment of Genetics

Dr. Herbert Friedman
Space Science Board
NAS/NRC

2101 Constitution Avenue
Washington, D. C.

Dear Herbert:

At a recent principal investigator meeting of the TV Experimenter Team of the
Mariner Mars 1971 mission it became apparent that the present NASA planetary
quarantine guideline for the decay life of an unsterilized Mars orbiter is that
it remain in orbit at least until December 21, 1988. This is a result of con-
fusion arising concerning two separate quarantine criteria: one which set the
period of biological exploration through the period ending December 21, 1988,
and the other which stated that unsterilized spacecraft in orbit should have a
lifetime of fifty years.

The first condition was set so that, using quantitative models, allocations of
specific risks could be made for individual missions as part of the overall 10
commitment. The purpose of the fifty year orbit decay period was different.

It was to allow unsterilized orbiters to be launched even before the biological
exploration had begun,with a period of decay long compared to the period of
biological exploration. This was to permit remedial action such as removal of

the decaying spacecraft from the atmosphere of Mars, if this was justified by

the results of the biological exploration. This is difficult if the period of
decay is equal to the period of biological exploration. It is also technologically
and financially impossible to plan on the capability of remedial action for the
1980's.

3

An unsterilized spacecraft put in orbit in 1971 that will certainly and irre-
versibly contaminate Mars on December 22, 1988 should count as a violation of
planetary quarantine in 1971. It is equivalent to the assertion that we have
sufficient knowledge at that time to decide to contaminate the planet with a
probability of unity. It is evident that this is contrary to the intent of the
Panel on Planetary Quarantine in their report of the Consultative Group on
Potentially Harmful Effects of Space Experiments, since in their report they
stated "no nation should use up more than 15% of the total contamination risk
during the first five years of exploration."

This conservatism is required not only because the "period" necessary for
biological exploration is uncertain and subject to reevaluation after biological
exploration starts in 1973, but because of the issue of the future potential
utility of the planet. It has been recognized that discussion of this issue
cannot sensibly commence before the acquisition of much more data concerning
Mars. An irreversible commitment to contaminate before such consideration of
future potential utility is irrational since the contamination itself may impose
difficulty and costly, if not impossible, constraints.
Dr. Herbert Friedman November 4, 1969
Space Science Board Page 2

We know of no meeting of NASA subcommittees or advisory groups, or Space Science
Board committees at which a change in the fifty year in orbit criteria, estab-
lished in 1964, was discussed. Such a change, if it is to be made, should be the
result of explicit discussion and not left to interpretation or misinterpretation
of the implications of policy decisions made concerning other quarantine criteria.

We have called this issue to the attention of Dr. Richard Young of the Bioscience
Division, NASA Headquarters, and Mr. Lawrence Hall, NASA Planetary Quarantine
Officer. Mr. Hall suggested alerting you so that it could be made the subject of
urgent Space Science Board review. The orbits that are the basis of present
scientific plans for the 1971 mission are, probably, compatible with a fifty year
in orbit requirement. However, because of what appears to be a change in NASA
policy, lifetimes in orbit as short as 17 years are now being considered. Since
such considerations would impact hardware decisions and science planning now under
way, immediate clarification is required.

Please keep us informed concerning any actions you plan to take about this matter.

Sincerely yours,

Me tlb br

Joshua Lederberg Elliott Cc. L

cc: Dr. George Derbyshire
¥ Dr. John Findlay
‘/ Mr. Lawrence Hall
/ Dr. C.-G. Heden
Dr. Orr Reynolds
“Dr. Carl Sagan
“ Dr. Robert Steinbacher
: Dr. Richard Young