5 comments

• Ray Van Dune

  May 24, 2023 at 8:28 pm

  I assumed that ULA was discontinuing the Hydrolox Delta 4 Heavy (with a perfect record) because BO had decided that Methalox was the way to go with the BE-4, which would power New Glenn and Vulcan.

  Then I hear that Lockheed is going to use Hydrolox for their parts of the BO lunar lander system. And that Hydrolox to Mars is far from a done deal…

  I understand no combo is best for all, but does anyone have a straightforward explanation?
• Tom Billings

  May 25, 2023 at 8:43 am

  Ray, the answer to why Delta Heavy IV and Delta IV were used may well be less in the propellant combination the vehicles used. It may have been more in the geographical location the vehicles were designed, built, supported within. Too often, the answer is Northern Alabama. That brings it down to one Richard Shelby, Alabama politician from 1963-2021, and high Seniority Senator till 2021.

  Senator Shelby chaired committees involving the budgets for NASA, and eventually used his leverage to “recruit” Boeing, Rocketdyne, ULA, and other companies to invest in major facilities in Northern Alabama, near Marshal Space Flight Center. ULA also built their Atlas V there. If they wanted contracts passed through Shelby’s sub-committees, and eventually the full Senate Appropriations Committee, they made sure that Senator Shelby’s voters were highly-paid and happily voting for incumbents.

  HydroLOX had strong advantages in the Moon Race years, when the emphasis was doing the job fast, and with one launch per mission. ISP performance über alles was the key to single launch/single mission Apollo getting to the Moon before the decade turned from 1960s to 1970s.

  *After* 1972, the key to funding became high-paying jobs in the right congressional districts. That meant using already employed engineers and craftsmen continuing what they knew as much as possible. What they all too often knew best about was HydroLOX.
• Richard M

  May 25, 2023 at 9:42 pm

  Hydrogen has more energy per unit mass, which makes it more efficient, delivering higher (400s+) impulse. That’s more useful on second stages and vehicles operating in space than it is at sea level, which is why you still see it used so often in the former roles (Vulcan’s Centaur upper stage is still using hydrolox, via upgrades of the trusty old RL-10’s). So in this respect, it makes more sense for a lander, which will only operate in space. Therefore, the same has to be true of the lander’s refueling vehicle . . . and that is what Lockheed is building.

  Hydrogen, at least so far as we know, is going to be easier to produce via ISRU on the Moon (because, water!), for purposes of refueling the lander on the surface down the road. So, in this respect, too, it makes sense for a lander.

  SpaceX standardized on methane for both stages of Starship despite its lower efficiency because a) simplified architecture and supply chain, b) less “pain in the ass” factor on the pad, and c) methane is much more readily synthesized on Mars, which is what Starship was design to go visit.
• Richard M

  May 25, 2023 at 9:45 pm

  Bob,

  For your next “Quick Space Links,” but honestly, this may deserve its own post! It turns out that ASAP is wigging out over safety concerns with Boeing’s Starliner: “The chair of a NASA safety panel urged the agency not to rush into a crewed test flight of Boeing’s CST-100 Starliner vehicle, calling for an independent “deep look” at technical issues with the spacecraft.”

  https://spacenews.com/nasa-safety-panel-skeptical-of-starliner-readiness-for-crewed-flight/
• Robert Zimmerman

  May 25, 2023 at 9:49 pm

  Richard M: I will report this tomorrow, though why anyone at this point takes anything that safety panel says seriously is baffling to me. Its track record is abysmal, not only in spotting real safety issues but in focusing on its real task.