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> The landing algorithm for the first stage uses convex optimization algorithms based on interior point methods, which were not available in the 1960s. Is this
by barbegal 6y ago
> The landing algorithm for the first stage uses convex optimization algorithms based on interior point methods, which were not available in the 1960s.
Is this level of optimisation really needed? I thought most of the landing was having enough fuel margin and then running a PID control algorithm during the landing burn.
- usrusr 6y agoI believe that the biggest obstacle in SpaceX's "hover slam" landing isn't calculating and controlling the burn but getting sufficiently precise input in time for those calculations. It must be a miracle of sensor fusion.
- pfdietz 6y agoApparently yes. See Lars Blackmore's chapter in the 2016 "Frontiers of Engineering" (National Academy Press) (free registration required) https://www.nap.edu/read/23659/chapter/10 https://www.nap.edu/read/23659/chapter/10 https://www.nap.edu/download/23659 https://www.nap.edu/download/23659 "SpaceX uses CVXGEN (Mattingley and Boyd 2012) to generate customized flight code, which enables very high-speed onboard convex optimization." This is actually a great example of a true NASA spinoff, btw. Lars Blackmore was at JPL before moving to SpaceX. Landing on Mars and landing a first stage back on Earth aren't the same problem, but they're close enough for the work to transfer.