Impact Images
International Space Station
Evidence of MMOD impacts on the ISS come from several sources. Photographs of the outside surfaces of the space station taken by astronauts directly or using robotic cameras is one source. Another sources is from equipment or other hardware that has been exposed to the space environment outside of ISS, then returned back to Earth. Lastly, MMOD impact sensors have been used on some of the ISS modules to directly detect impacts. There are future efforts to expand the impact-sensing capabilities of ISS and other spacecraft as well. Additional technologies are being explored to detect MMOD impacts and report the impact location, amount of damage, and estimate impactor size, velocity, and direction.
ISS: Airlock Shields
After 8 years of exposure to the ISS space environment, two MMOD metal shielding panels were removed from the outside of the Airlock Module in order to make room for external storage containers. The inspection team was able to find 58 impacts on these two panels even though they were located in a lower-risk area on ISS.
ISS: Ammonia Tank Assembly No. 3
An Ammonia Tank Assembly No. 3 (ATA-3) that had been stored external to the ISS
since 2002 was returned on Shuttle mission STS-131 eight years later in April
2010. The post-flight MMOD inspection identified 49 impact locations with the
largest being 0.84mm in diameter.
ISS: Port Side No. 4 (P4) Radiator Panel
As of 2019, the largest observed impact damage on ISS is an impact that punched
through one of the ISS port-side radiator panels. This radiator panel is part
of the solar array cooling systems. The damage shown below is the "exit side"
hole, whereas the "entry side" hole on the opposite side is smaller. This panel
is a thick honeycomb panel that contains many metal coolant tubes separated by
large gaps. Fortunately, this impact just missed one of the coolant tubes.
Top Image: Actual Damage
Port Side No. 4 (P4) Radiator Panel
Port Side No. 4 (P4) Radiator Panel
Bottom Image: Simulated Damage
Date Shot: 2/12/2015
Projectile Type: Aluminum Sphere
Projectile Diameter: 4.5mm diameter
Impact Velocity: 7.08 km/s
Impact Angle: 50 degrees
Date Shot: 2/12/2015
Projectile Type: Aluminum Sphere
Projectile Diameter: 4.5mm diameter
Impact Velocity: 7.08 km/s
Impact Angle: 50 degrees