(Georgia Institute of Technology, 2017-09)
Sforzo, Brandon A.; Braun, Robert D.
Flight data provided by SpaceX for flights was analyzed to demonstrate the applicability of telemetry
during SRP to Mars relevant conditions. This information was provided under the framework of a
public-private partnership with NASA, executed as a Space Act Agreement. Analysis focused on the
entry burn portion of the trajectory. Flight conditions were provided to confirm SRP occurred during
an applicable range of mach numbers and dynamic pressures to match Mars SRP initiation conditions.
Vehicle trajectory and attitude history were provided for the SRP segment as well as onboard
sensors for temperature, pressure, heat flux, and strains to compare between missions. Furthermore,
NASA airborne assets provided thermal imagery of the first stage during SRP to provide comparison
to onboard data. Plume tracking analysis was compared to dynamic data from sensors with little correlation.
Analysis of these onboard sensor data and examination of the details for several missions,
the performance of the Falcon 9 vehicle during SRP appeared to be well behaved for these flights.
This study illustrates that SRP methodology implemented for the Falcon 9 first stage entry does not
adversely affect the vehicle and shows promise for future implementation.
(Georgia Institute of Technology, 2017-09)
Braun, Robert D.; Sforzo, Brandon A.; Campbell, Charles H.
Advanced robotic and human missions to Mars require landed masses well in excess of current capabilities. One approach to safely land these large payloads on the Martian surface is to extend the propulsive capability currently required during subsonic descent to supersonic initiation velocities. However, until recently, no rocket engine had ever been fired into an opposing supersonic freestream. In September 2013, SpaceX performed the first supersonic retropropulsion (SRP) maneuver to decelerate the entry of the first stage of their Falcon 9 rocket. Since that flight, SpaceX has continued to perform SRP for the reentry of their vehicle first stage, having completed multiple SRP events in Mars-relevant conditions in July 2017. In FY 2014, NASA and SpaceX formed a three-year public-private partnership centered upon SRP data analysis. These activities focused on flight reconstruction, CFD analysis, a visual and infrared imagery campaign, and Mars EDL design analysis. This paper provides an overview of these activities undertaken to advance the technology readiness of Mars SRP.