Pilot control and stabilization of a rate-controlled vehicle in hyper-gravity

Astronauts experience multiple altered gravity environments during space missions, in which they need to maintain sufficient performance for vehicle control tasks such as planetary landing and vehicle docking. We aimed to use hyper-gravity as an altered gravity test-bed to study pilot manual control performance. A long-radius (7.6 m) centrifuge (NASTAR Center's ATFS-400) was utilized to produce hyper-gravity. Subjects (N=12) were tasked with trying to “keep the cab as upright as possible” using a rotational hand controller in response to a pseudo-random roll disturbance in the dark. The control law was “rate-control” such that stick deflection was proportional to commanded roll rate, similar to a lunar landing vehicle. During initial exposure to hyper-gravity, pilot performance showed significant degradations relative to the 1 G performance baseline, in terms of increases in the root mean square (RMS) error in roll tilt. On average in hyper-gravity, RMS scores increased by 25% over 1 G levels. Subjects also reported increases in workload in hyper-gravity. Performance significantly improved in hyper-gravity over time. After several minutes the performance in hyper-gravity returned to near the 1 G baseline performance level. This is likely to be a critical time period for planetary landings with fuel constrained vehicles. These control impairments may impact not only flight performance, but also vehicle and crew safety.