Conceptual Cost Estimation for Recovery and Refurbishment Operations of Reusable Launch Vehicles

Kurzfassung

The launch vehicle sector is being revolutionized by the successes of SpaceX and Blue origin, partly because of their innovative commercialization and operations. This is increasing the interest in reusability as a possible way of reducing launch costs, with a wide range of proposed launch vehicle concepts. Some of these proposals are driven by post-flight operations, such as the In-Air Capture approach which could provide fast turn-around times and reduce operational complexities, or the Return To Launch Site (RTLS) method using ballistic rockets to avoid large post-flight recovery costs to the launch site. This study attempts to estimate these later costs to assess the suitability of the different concepts. This is done by analyzing recovery activities, constructing engineering build-up methods and surveying the literature for parametric, analogy and data for the specific components. In addition, a preliminary analysis of the maintenance and refurbishment costs is done by using some parametric relationships. The project focuses on operation modes for two types of reusable first stages, a vertical take-off horizontal landing (VTHL) winged first stage and vertical take-off vertical landing (VTVL) ballistic first stage. The operation modes analyzed are he IAC for the VTHL configuration, and down range landing (DRL) on a floating barge or adapted vessel and RTLS for the VTVL configuration, although some of the estimating approaches and data could be easily extended to other types of operation modes and configurations. In addition, the mission profile for the in-air capture and towing is defined for comparison between different aircraft types to provide inputs to the cost model. The study found that a modified secondhand B747-400 is suitable for the towing operations in the IAC mode. In addition, the IAC and DRL recovery costs were found to be lower than those estimated with traditional CERs in the literature based on the Space Transportation System recovery and similar past historical studies, while RTLS recovery costs where almost negligible. In addition, the IAC recovery mode could have lower recovery costs per flight compared to the SpaceX approach of DRL with launch rates larger than 30 per year. Maintenance and refurbishment costs were based on hydrogen stage concepts and were shown to be lower for the VTVL hydrogen configuration, partly as a consequence of the lower mass compared to VTHL, although future studies would need to make a closer analysis with a detailed built-up method based on the required activities and spare costs.