Mission Design and Sensitivity Analysis for In-Air Capturing of a Winged Reusable Launch Vehicle

The cost of access to space has always been a major obstacle for space exploration. With the growing commercial success of Reusable Launch Vehicles (RLVs) however, low cost and more frequent launches become achievable. The innovative ‘In-Air Capturing (IAC)’ mode proposed by DLR, involves capturing of a winged launcher stage mid-air using an aircraft and towing it back to the launch site. By using the aircraft for propulsion, the RLV stage no longer requires its own propulsion system for descent, thereby reducing the overall launch mass and cost. A typical recovery profile of IAC starts when the winged first stage separates from the launch vehicle. During IAC, the RLV and the towing aircraft must come into proximity of each other at around 10 km altitude to attempt an unpowered formation flight. However, uncertainties can lead to non-ideal conditions for the capturing attempt. The RLV could deviate from its nominal trajectory due to variations in separation conditions. The towing aircraft itself can correct for some errors in the trajectory and improve chances of capture. But non-ideal conditions at the beginning of the formation flight can make it challenging to maintain longer formation time, and reduce the probability of successful capture. Thus, the following paper will evaluate the effect of RLV separation conditions on the success rate of IAC