Hubble Space Telescope Angular Velocity Estimation During the Robotic Servicing Mission

Abstract

In 2004 NASA began investigation of a robotic servicing mission for the Hubble Space Telescope (HST). Such a mission would require estimates of the HST attitude and rates in order to achieve a capture by the proposed Hubble robotic vehicle (HRV). HRV was to be equipped with vision-based sensors, capable of estimating the relative attitude between HST and HRV. The inertial HST attitude is derived from the measured relative attitude and the HRV computed inertial attitude. However, the relative rate between HST and HRV cannot be measured directly. Therefore, the HST rate with respect to inertial space is not known. Two approaches are developed to estimate the HST rates. Both methods utilize the measured relative attitude and the HRV inertial attitude and rates. First, a nonlinear estimator is developed. The nonlinear approach estimates the HST rate through an estimation of the inertial angular momentum. Second, a linearized approach is developed. The linearized approach is a pseudo-linear Kalman filter. Simulation test results for both methods are given. Even though the development began as an application for the HST robotic servicing mission, the methods presented are applicable to any rendezvous/capture mission involving a non-cooperative target spacecraft.

Relative attitude and position estimation for a tumbling spacecraft

“…Motivated by the Hubble robotic servicing mission, a nonlinear algorithm has been developed to estimate the rotation rate and attitude for a tumbling spacecraft [14]. However, only the relative rotational motion is considered, and the properties of the sensor and process noises as well as the inertia parameter uncertainties are not taken into consideration.…”

“…Because of the cruel space environment and the limitation of the lifetime, a spacecraft may be in failure or out of control due to some malfunctions. Therefore, the capture for a tumbling spacecraft has received detailed attentions in recent years [1,10,14,17].…”

“…Several space programs have been completed or are being developed as technology demonstration of these tasks, such as JAXA's ETS-7 [7], NASA's DART program [4], DARPA's Orbital Express program [15], and SUMO program [3]. Because of the cruel space environment and the limitation of the lifetime, a spacecraft may be in failure or out of control due to some malfunctions.…”

Non-cooperative rendezvous and interception —A direct parametric control approach

“…In certain circumstances, spacecraft rendezvous or inception with a non-cooperative target spacecraft is required, and such a problem has also attracted much attention in recent years ([11]- [17]). The difficulty underlying in such a problem * This work has been partially supported by the Natural Science is that the orbital model of the target is not assumed to be known.…”

“…Spacecraft rendezvous has remained a challenging problem for many years ([1]- [4]), and has attracted much attention (e.g., [5]- [17]). Reported results are mainly fall into two categories.…”