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Threat Assessment

Determining the Risk

After the ballistic limit equations and the near earth environments are defined, a computer program called Bumper is implemented to determine the probability of surface impacts and/or shield penetration.

Case Studies

At the HVIT, meteoroid and orbital debris threat assessments have been performed on a variety of manned and unmanned spacecraft. The following case studies provide some insight into the capabilities of the Bumper code

Space Station


In recent years, the design and development of shielding for the International Space Station (ISS) has been one the primary tasks at the HVIT. Numerous advanced ISS shielding concepts have been evaluated.



Mission support for the shuttle program has been a primary focus at the HVIT. Significant effort has gone towards prediction and mitigation of on-orbit impact risk.



The familiar Extravehicular Mobility Unit (EMU) is used for spacewalks by shuttle astronauts and will also be used during the construction of the International Space Station.



The Integrated Threat Assessment is a "program level" evaluation of the meteoroid and debris risk to the entire ISS vehicle. The assessment considers both the baseline conditions mandated in the Station program requirements and the best estimate "real world" conditions currently anticipated for the missions.



On Jan. 11, 1990, The Long Duration Exposure Facility (LDEF) was retrived by STS-32 after 69 months (5.7 years) in low earth orbit. 57 experiments on the satellite were dedicated to on-orbit impact detection and projectile remnant recovery. The HVIT performed an evaluation of the expected number of impacts on each facet of the spacecraft.



Iridium is a communications network formed by a constellation of 66 satellites. The HVIT was hired to assess the probability of failure of one of the satellites due to meteoroid and orbital debris impacts.



The Russian space station Mir has been a subject of analysis at the HVIT since 1990. The facility has performed numerous assessments on various station configurations and attitudes.



The X-38 is the X-series name given to the prototype ISS Crew Return Vehicle (CRV). The HVIT has performed detailed assessments investigating post-impact vehicle integrity and mission assurance.