Shuttle reboost of the space station using the automatic reboost software requires jet-firing separation to avoid excitation of the joined Shuttle/ISS structural natural frequencies. Accurate specification of this jet-firing separation requires measurement of the on-orbit joined structure natural frequencies. A brief execution of the reboost software using benign parameters, such as burn length, will allow acquisition of structural dynamics data to validate the preflight estimate of the structural natural frequencies and damping and, thus, the jet-firing separation time.
The structural natural frequencies can be measured using the shuttle inertial measurement unit downlinked data, and the jet-firing separation time can be implemented by display inputs by the crew. This DTO is appropriate for shuttle flights to the ISS between availability of OI-28 reboost software and availability of the vernier jet reboost capability and which have a significant structural configuration difference from previous flights.
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