Hayabusa - Recovery Operation and Return Voyage Back to Earth
- Paper number
IAC-07-A3.5.01
- Author
Dr. Junichiro Kawaguchi, Japan Aerospace Exploration Agency (JAXA)/ISAS, Japan
- Coauthor
Dr. Makoto Yoshikawa, Japan Aerospace Exploration Agency (JAXA), Japan
- Coauthor
Dr. Takashi Kubota, Japan Aerospace Exploration Agency (JAXA)/ISAS, Japan
- Coauthor
Dr. Kazutaka Nishiyama, Japan Aerospace Exploration Agency (JAXA), Japan
- Year
2007
- Abstract
The operation of the Hayabusa (MUSES-C) spacecraft was re-established in January of 2006 through the loss of contact for seven weeks after the fuel leak incident at the end of 2005, when it successfully performed the world’s first touch-downs and lift-offs two times. During one year since then, the spacecraft had undergone the battery re-charge operation and the refurbishment of the subsystems onboard. The ion engines system aboard were verified last April to May and the performance of it was confirmed normal as that prior to the arrival at the asteroid, Itokawa in 2005. The spacecraft lost already two reaction wheels aboard and only one wheel is left usable now. Besides, the chemical propulsion system aboard lost its fuel and oxidizer, and the only means the spacecraft’s attitude is reoriented is the Xe gas for ion engines use. Fortunately, the spacecraft is equipped with four ion engines heads and the spacecraft attitude is three axis-stabilized now with very small torque taking the advantage of the Xe gas. Thus, anyhow the spacecraft attitude was well maintained and articulated as planned since last year. The flight period left is three years, and it was revealed that even the compensation for the solar radiation pressure torque amounts more than the momentum capability owing to the Xe gas. In this context, the project team decided to adopt a new attitude control scheme which utilizes the solar radiation pressure to make the spin motion passively stabilized with respect to the Sun, so that the spacecraft spin axis automatically can track the Sun direction. The flight results simply showed that the attitude control scheme functioned as intended and has tracked the sun direction all the time. No fuel was consumed for the period, once the attitude control was performed to place the initial spin direction into the intended direction. The spacecraft this January successfully performed the closure of the reentry capsule, which at the same time, could push the sample catcher canister into the capsule by latching and sealing operation. The power for the operation was provided from the above-mentioned refurbished battery. Not only electric current information but the temperature history of the capsule was obtained, and they conclude the operation was very successful. This operation and the sample collection system design actually worked well demonstrating the function in space. This will lead to the subsequent missions design. From the end of this March, the spacecraft started its ion engine toward the return cruise back to the Earth. The spacecraft stopped the spin motion, while the momentum is held by the remaining reaction wheel. Both solar radiation torque and the ion engines leak torque apply the disturbance to the spacecraft attitude. Currently, the spacecraft has successfully established the new attitude control strategy, and has coped with the disturbance due to not only solar radiation but ion engine thrust. The paper will describe how the project team has coped with the difficulty and will present the return flight trajectory synthesis that takes the propulsion and attitude constraints into account. The flight experience will contribute to the subsequent planetary missions.- Abstract document