Somewhat Confused Defenders Of SLS (Updated)

The Space Launch System "Jobs Program", Paul Spudis

Spudis: "In contrast to some misleading promotional slight of hand, the SLS will not "take astronauts to Mars" but it could launch ready-to-assemble pieces for a human Mars mission into space (it would take between 8 and 12 launches of an augmented SLS to get a fully fueled manned Mars vehicle into space and prepared for departure to Mars)."

Commenter: "... I'm sort of surprised to see you acting as though launching most of our propellant for a Mars mission from Earth is a good idea."

Spudis: "Where in this post have I advocated that?"

Keith's 2 May note: Let's see: Spudis writes "it would take between 8 and 12 launches of an augmented SLS to get a fully fueled manned Mars vehicle into space and prepared for departure to Mars." If it is "fully fueled" and one presumes launched from Earth on SLS rockets, then he just said that the propellant for the mission to Mars comes from Earth, right? FWIW I attempted to post this comment but Dr. Spudis declined to allow it to be posted. This is sort of silly given that the first paragraph of Spudis' article centers around a linked posting on NASA Watch and an article on Buzzfeed that quotes me. C'mon Paul.

Keith's 3 May update: well now my comment has been un-deleted and approved (Spudis says they were never deleted so I will defer to his explanation). Spudis tersely points to another response where he says that he really meant refueling from lunar ice. Not a bad idea - but that is not what he originally said - or even implied.

This article has lots of classic SLS defenses and attacks. Spudis derides Falcon Heavy saying that he's never seen a Falcon Heavy and "but as no Falcon Heavy has yet to fly, we have no idea of what its cost would be." Well, SpaceX has been posting prices for Falcon Heavy for some time. They revised their prices just the other day. As for having never flown - correct but wait: the Falcon 9, three of which will comprise a Falcon Heavy, have flown multiple times. Yet Paul hugs his SLS even more tightly even though there is no SLS vehicle lying around - anywhere in a hangar.

Moreover, unlike the Falcon Heavy (which uses identical Falcon 9s) SLS has never flown as "SLS". Right now the SLS is a bunch of parts that have never been assembled as a single vehicle. The SRBs to be used by SLS are designed Shuttle design but have never flown. SLS uses old Shuttle engines that have never been flown in a SLS configuration. And the SSMEs and SRBs are attached to a new core structure that has never flown.

Falcon 9 has been flying for years. SLS will not fly for another 2-3 years and then will have another 3-4 year gap before it flies again. Yet Spudis et al think that SLS, which will fly twice in the next 6-8 years, will somehow be less risky to use than the Falcon 9/Heavy which will have had dozens and dozens of flights in the same period of time at a collective cost that will still be dwarfed by what SLS costs to build and operate - for 2 flights.

Like I said, SLS supporters are somewhat confused.

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This page contains a single entry by Keith Cowing published on May 3, 2016 9:45 AM.

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