INFORMAL MEMO

TO:  Distribution

FROM: Team Leaders, LP/S Phase 1 Integrated Product Team (IPT)

SUBJECT: LP/S Phase 1 IPT Risk Mitigation and Flight Demonstration
Experiments June 19 Board Minutes

The LP/S Phase 1 IPT Board met Wednesday, June 19, 1996, to review a
proposed risk mitigation data analysis opportunity.

Mir-I Spacecraft Contamination Sources:  Identifying and Reducing ISS
Program Risks
EM2/S.Koontz summarized the recent analysis of the brackets which supported
the Docking Module camera (up on STS-74, returned on STS-76) for five
months.  Analysis suggests that the sides facing the Mir solar array
controlling mechanisms were contaminated by leaks from the hydraulic control 
system.  Outward facing bracket surfaces facing the Russian hardware turned
brown.  The inward surfaces remained white.  The Alpha (absorption) changes
from 0.2 to 0.5 (O is white; 1 is black).  ISS allocated 30 Angstroms per
year to station molecular deposition.  Analysis of the camera brackets
suggests 16 Angstroms permanent, non-reevaporating, deposition per day.
 Even larger silicone deposition rates are sugested by QCM data from: 1)
DTO-829 QCM data taken during the sensor cooling period before Russian
thruster firings (200 Angstroms per day), 2) Euro-Mir QCM sensor data (200
to 400 Angstroms per day, 3) Russian QCM sensor data ( 400 Angstroms per
day). The available  QCM data is probably worst case, does not include
re-evaporation periods.

If Mir-1 is a reasonable example of ISS Russian segment contamination
performance, then outgassing and deposition during ISS operations may be
much higher than specifications allow.  Contamination originating in Russian 
segment hardware,  which is probably similar to the present Mir
hardware, can reduce the ATCS radiator life to less than two years, the
passive radiators to less that one year, and the photovoltaics to less than
five years. The  ISS program life requirement is fifteen years.  The Board
requested that Fred Kuo evaluate the proposed additional analysis and risks
to Phase 2/3.  The Board approved funding $31.3 K to obtain additional Mir
data from T & M Engineering.  Evaluation of Russian silicone usage and
materials selections for FGB and service module is in progress.



signed                                signed
______________________________        ______________________________
OB/Tri X. Nguyen, NASA Team Leader    HS-40/Robert Gedies, Boeing Team
Leader


Encl. 1: Action Item

Ph1-146  Mir-I Spacecraft Contamination Sources:  Identifying and Reducing
ISS Program Risks

Review the proposed analysis and confirm it will provide additional data
which contributes to the definition of the Mir contaminants.

Due:  July 10, 1996

Action:  OF/F.
Kuo