WBC as EDS Update

I also wanted to post a quick update about that WBC as EDS idea. Ross Tierney (the guy behind the DIRECT concept) ran some simulations for me. Apparently for the specific design of the EDS, the 6-engine WBC wouldn’t quite work. Apparently the thrust on the RL-10s is too low to deal with the fact that the EDS has to put itself into orbit in the first place (since the Ares V doesn’t have the oompf to do the job all by itself) before it could be used for lunar transfers.

You might be able to get the design to work by going to RL10-Cs or RL60s if either became available, but your system would no be the same as the commercial WBCs, and wouldn’t have much of a propellant fraction advantage over the current EDS design. And you’d still be fielding new engines, and designing a whole new stage.

OTOH, if on-orbit propellant delivery became a reality, the standard WBC design would be substantially better than the EDS.

So basically, if you insist on having your lunar transfer stage pull double duty as a third stage to compensate for the fact that your booster can’t actually get its payload into orbit with two stages (because one of the two is a crappy performance SRB that is only being kept around because nobody wants a bunch of unemployed rocket nerds roaming the streets of northern Utah), then the Wide Body Centaur isn’t an option, and you better develop the Stick and that J-2X. If you actually want a real cislunar transportation system, you need to be able to transfer propellants on orbit, and at that point, the WBC is an excellent system to start with.

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Jonathan Goff

Jonathan Goff

President/CEO at Altius Space Machines
Jonathan Goff is a space technologist, inventor, and serial space entrepreneur who created the Selenian Boondocks blog. Jon was a co-founder of Masten Space Systems, and is the founder and CEO of Altius Space Machines, a space robotics startup in Broomfield, CO. His family includes his wife, Tiffany, and five boys: Jarom (deceased), Jonathan, James, Peter, and Andrew. Jon has a BS in Manufacturing Engineering (1999) and an MS in Mechanical Engineering (2007) from Brigham Young University, and served an LDS proselytizing mission in Olongapo, Philippines from 2000-2002.
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4 Responses to WBC as EDS Update

  1. Adrasteia says:

    Apparently for the specific design of the EDS, the 6-engine WBC wouldn’t quite work. Apparently the thrust on the RL-10s is too low to deal with the fact that the EDS has to put itself into orbit in the first place

    Can anyone else see the bigger problem yet?

  2. Mike Puckett says:

    Is this using the 5 meter Atlas core as the 1st stage and outbard boosters?

  3. Jon Goff says:

    Mike,
    This analysis was run using a 6-engine WBC on top of a DIRECT core and 2×4-segment RSRMs, if that’s what you’re asking.

    ~Jon

  4. Mike Puckett says:

    Gotcha!

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