mal surfaces and optics. The effect of debris impact on a particular spacecraft is strongly dependent on the spacecraft's design; debris is far more likely to damage unprotected spacecraft than those that were designed with due consideration of the meteoroid and orbital debris environment. Components that are difficult to protect from debris (including photovoltaic arrays, suites of communications antennas, and sensors) may, however, be at risk even in a well-designed spacecraft.
Assessments of the damage caused by debris impact are needed to (1) design spacecraft components and shielding capable of surviving debris impact, and (2) better understand the effect of collisions on the evolution of the future debris population. Since it is very difficult to gather data from the rare impacts of medium-sized or large debris in space, assessment of the potential damage such impacts can cause is accomplished primarily through ground-based experimental testing and analytic/numeric methods. Experimental hypervelocity impact testing generally provides the majority of information for such assessments; analytic and numeric tools currently mainly supplement and extend experimental results.
Current hypervelocity impact facilities cannot, however, simulate all relevant debris compositions, shapes, and velocities, and data on the vulnerability of different spacecraft components to debris impact are limited. Although analytical and numerical techniques can be used to predict impact damage for regimes that hypervelocity testing cannot simulate, these predictions can be inaccurate unless they are based on experimental data. Unfortunately, many of the experimental data are not available due to the general inaccessibility of hypervelocity facility capabilities and the impact data generated at these facilities. As a result of these limitations, current spacecraft protection systems may not provide their desired level of protection, and current models of the effects of collisions on the future debris population may be inaccurate.
To facilitate the development of improved models of debris impact damage and enable the development of improved debris shielding, the committee recommends the continuation of research to characterize the effects of hypervelocity impacts in the following areas:
further development of techniques to launch projectiles to the velocities typical of collisions in LEO;
improved models of the properties of new spacecraft materials;
studies of impact damage effects on critical spacecraft components;
development of analytical tools consistent over a range of debris impact velocities, shapes, and compositions; and
improved models of catastrophic space object breakup due to debris impact.