SpaceX

Starship Conveyor Flight System
Recently I've been trying to gain some insight into all we've heard about SpaceX plans for orbital refueling including NASA's endorsement of them for HLS Starship. Many pundits claim SpaceX will require enormous numbers of tanker flights to pull this off - but it's possible they don't have all the information...SpaceX are currently building three orbital launch sites for Starship, one on dry land at Boca Chica, Texas and another two on floating platforms, i.e. Phobos and Deimos. If the Super Heavy booster can land downrange on these platforms, that should save a significant amount of propellant (compared to returning booster to original launch site), which would allow them to haul the maximum payload possible to space, without expending the booster.If we do an ocean landing, the performance hit is actually quite small at maybe in the order of 15%. If we do a return to launch site landing, it's probably double that, it's more like a 30% hit (i.e., 30% of payload lost). ~ Elon MuskHence it’s possible SpaceX will launch from Boca Chica then land the booster downrange on Deimos, which is currently docked at Brownsville, Texas. This should allow them to launch a full stack again from Deimos and land the booster downrange on Phobos (which has already been towed from Port of Galveston, Texas to Pascagoula, Mississippi). Then the long journeyed booster could fly retrograde back to Boca Chica, ready to commence this conveyor launch process again.Elon suggests they will need to launch four tankers to refuel each Mars Starship in orbit, and this ratio will likely increase for lunar excursions, where more propellant is needed for propulsive landing. Hence a tanker could depart with a full load of propellant from Boca Chica, offload at an orbital fuel depot then land at the first link in the chain i.e. Deimos. After launching again with a full propellant load from Deimos, the tanker could visit the same fuel depot then return to Boca Chica. Overall this procedure should reduce the number of tanker flights required to fill the depot because significantly more propellant could be delivered to orbit with each tanker flight, due to a more ergonomic use of infrastructure (compared to operating from a single launch site).(How will Starships be transported to the floating platform?) They will fly there from our launch site. ~ Elon Musk ~ Elon MuskFortunately SpaceX intend to manufacture methalox propellant onboard these floating platforms, so essentially they will produce the payload required for these tanker flights in-situ. That should allow the comparatively small number of cargo and crew Starships to depart from Boca Chica, thus retaining the floating platforms for more numerous tanker flights.This improved launch efficiency might explain the rather conservative estimate for the number of tanker flights required for each Mars mission, and the feasibility of sustainable moon operations. Elon suggests it should only take 5 or 6 tankers to fully refuel Starship, which implies each tanker could deliver ~220mt to orbit, given Starship’s maximum propellant capacity of 1,200mt.Eventually this chain of launch sites might stretch all the way to the Cape to further increase launch efficiency. No doubt the FAA would want to see plenty of precision landings before they allow Starship or Super Heavy to descend over Florida - although if anyone can do it it’s SpaceX.Gotta love a joined up space effort!

Submitted May 13, 2021 at 04:20PM by CProphet
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NASASpaceFlight.com

SpaceX acquires former oil rigs to serve as floating Starship spaceports

SpaceX has acquired two former oil drilling rigs to serve as these floating spaceports. Named Phobos…

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