INTERNATIONAL SPACE STATION EXTERNAL ENVIRONMENTS (ISS EXTERNAL ENVIRONMENTS)
Research Area: Technology Development and Demonstration: Spacecraft and
Orbital Environments
Expedition(s): 1-ongoing
RESEARCH OBJECTIVES
The International Space Station (ISS) is subject to several sources of contamination, including
component outgassing and breakdown, water dumps, thruster plumes from both the service
module and visiting spacecraft, orbital debris, and micrometeorites. Several papers provide
data that model these different contamination sources on the ISS. Certain surfaces of the ISS
are particularly sensitive to contamination; knowledge of the station environment leads to
mitigation strategies and feeds back into materials and mission designs for future missions.
EARTH BENEFIT
New knowledge is expected to be the major benefit of this project.
SPACE BENEFIT
ISS External Environments provides new knowledge to advance space exploration.
RESULTS
The data are used to help predict
component life cycles; provide
data that are relevant to
performance; create operational
rules for spacecraft and
extravehicular activity
(spacewalks); and feed into future
mission design considerations.
NASA’s Image Science & Analysis
Lab produces regular reports of
their findings. ISS engineers use
the data for the various studies
that are reported here. Below is a
sample of these results to date.Liquid droplets of partly reacted
propellants are produced by thruster exhaust plumes from visiting spacecraft. Both the
chemical nature and the physical acceleration of the drops can produce pitting, mechanical
erosion, and other damage on surfaces. For critical surfaces, such as solar arrays, the models
influenced flight rules for array-positioning during thruster firings (Alred 2003; Pankop 2004).
An experiment was performed in 2001 to document a water dump and venting event with
video for analysis. The venting was characterized from the imagery, including the extent of the
cone of the vent, number of particles outside the cone, and velocities of ice particles. Because
S123E010030 – Backdropped by a blue and white part of Earth, a
close-up view of the International Space Station is seen from Space
Shuttle Endeavour as the two spacecraft begin their relative
separation. NASA image.