SpaceX Starship Hot Staging - From Concept to Flight
SpaceX’s Starship uses a hot-staging maneuver for its stage separation, in which the spacecraft’s upper-stage engines are ignited before the booster engines are completely cut off. While such a maneuver has been used on other space launch vehicles, it had never been done on a vehicle of this size—at nearly 400 feet tall, Starship is the largest rocket ever built. With hot staging, the rocket never stops accelerating during separation, so it is a more efficient method than traditional stage separation. However, hot staging produces plume impingement against the booster’s shield in the confined interstage space between the booster and the upper stage, creating an environment that is complex and not well understood. To analyze Starship’s hot staging maneuver, researchers in the Fluid Dynamics Branch at NASA’s Marshall Space Flight Center performed computational fluid dynamics (CFD) simulations using the Loci/CHEM flow solver. These simulations included steady-state simulations as well as sophisticated time-accurate moving body simulations on a variety of iterations of the Starship geometry. Due to the scale of the problem, meshes of approximately 500 million cells were required. The team simulated various engine startup sequences and analyzed the resulting aerodynamic loads. Flight data from Starship’s second Integrated Flight Test (IFT2) compared favorably to the CFD results. These simulations supported SpaceX in designing a successful hot-staging separation.
Simulating all of Starship including the booster is extremely computationally intensive. Simulations of this size could not be completed in a timely manner without NASA supercomputing resources.
Brian Richardson,
NASA Marshall Space Flight Center
Quick Facts
- Stage separation utilizing hot staging has never been done before on a vehicle of this size.
- Computational fluid dynamics (CFD) simulations were performed, including simulating the separation and motion of the booster as it drifted away from Starship.
- NASA Advanced Supercomputing facility resources were required to complete this work. These CFD simulations required very large meshes (500+ million cells) and ~40 million CPU hours on the Pleiades supercomputer, and generated many terabytes of data.
- Future Loci/CHEM source code optimization and increases in the amount of HECC resources will allow NASA researchers to make better use of the more computationally intensive, higher fidelity tools for lunar mission planning, while still maintaining production-level run times.
Researchers
- Jason Liu, NASA Marshall Space Flight Center Please enable Javascript to see email address.
- Brian Richardson, NASA Marshall Space Flight Center Please enable Javascript to see email address.
