Study of Rotor-Jetpack-Wind Aerodynamic Interaction for Mid-Air Helicopter Delivery on Mars

Mid-Air Helicopter Delivery (MAHD) is a new Entry, Descent and Landing (EDL) architecture for enabling future Martian helicopter-only missions (e.g., Mars Science Helicopter (MSH)), that offer much greater in situ mobility compared to traditional rover missions at lower cost. This EDL concept utilizes a delivery jetpack to slow down the rotorcraft free fall after separation from the parachuting backshell, thus avoiding unfavorable rotorcraft descent aerodynamics, and provides suitable aerodynamic conditions for helicopter take-off in mid air. While Martian rotorcraft operation has been successfully demonstrated by the Ingenuity system, the mid-air helicopter take-off from a self-propelled jetpack platform has been identified as one of the critical aspects of this EDL strategy. This paper presents the development of an experimental sub-scale test-bench to assess the aerodynamic interactions between the MSH, a jetpack analogue system, and the wind to evaluate the technical feasibility of MAHD. Aerodynamic measurements and various qualitative and quantitative flow visualizations were performed in a (1 atm / 1 g) environment and compared to computational fluid dynamics (CFD) simulation for validation. We also demonstrate in-flight capabilities of wind sensing as well as active trimming of the rotorcraft under relative crosswinds using an integrated force-torque sensor to be placed between rotorcraft and jetpack.