Monday, December 13, 2021

SpaceX Moves Booster 4 Back Onto OLM

After a lot of talk and rumors over the last few weeks about booster 4 being moved to the Orbital Launch Mount, it was moved today.  While it's easy to expect them to start doing the static testing that's a barrier to trying an orbital launch, this is the third time that booster has been on the OLM and there are no guarantees this isn't some sort of test fit that will be followed by dismounting B4 soon.  Still, Elon Musk said he hopes to do the first attempt at orbit "early in January" and that's less than three weeks away.  If they're going to make it, those tests must become high priority. 

Screen capture from Lab Padre.   As it says.

As we've said dozens of times, the first boosters will have 29 Raptor engines.  That helps make this launch pad among the most complex the world has ever seen.  If not the most complex launch mount.  Eric Ralph at Teslarati supplies some details.

... By all appearances, Super Heavy hold-down clamps – mechanical devices designed to hold the booster to its work stand or keep it immobile on the launch mount during a variety of test – work by reaching inside the lip of the booster’s aft ‘skirt,’ which sports a very sturdy ring of steel that 20 Raptor Boost engines mount to and push against. The 20 clamps fit precisely between each of those 20 outer Raptors and grab onto Super Heavy from the inside.

Just before liftoff, all 20 hold-down clamps will rapidly retract back into the orbital launch mount. So will another 20 small quick-disconnect umbilical panels designed to supply every single Raptor Boost engine with the gases they need to ignite. The primary booster quick-disconnect – which connects Super Heavy to power, communications, and propellant supplies – will also retract into a hooded enclosure at some point during the process. Finally, a giant, swinging arm located about halfway up Starbase’s ‘launch tower’ will retract a similar quick-disconnect panel for Starship fueling, retract two claw-like support arms, and swing back for liftoff.

Eric goes on to say that there are probably even more than those just described.  Every Starship launch will require at least 44 separate devices to actuate in rapid and precise succession – 41 for Super Heavy and at least 3 for Starship.  It's my impression that a lot of this hardware was borne out of the idea that was first talked about earlier this year: to move as much infrastructure as possible out of the vehicle and onto what Elon called, "Stage Zero" - the OLM.  All in an effort to minimize the mass of the booster and maximize its payload.  That complicated the design of the OLM and seems that it must have contributed delay to getting the OLM ready for testing.

As of now, the Cameron County road closure page for SpaceX shows the next round of closures starting Wednesday 12:00 p.m. to 8:00 p.m., with "secondary" (backup) days of Thursday (same time) and Friday 8:00 a.m. to 2:00 p.m..   It's probably wishing a bit too much to hope they'll do any testing of B4 this week. 


  1. What do you think of Elon Musk? Why has he done more in a few short years than NASA has done in the last decade?

    1. I could probably do a long blog post on this, but NASA has devolved into being like any other government agency. They arrange make-work programs to get jobs into congressional districts expecting that the jobs will get congress critters (re-) elected.

      In the 80s and 90s, my wife worked on the Cape on the unmanned and then Space Shuttle sides. In the early 90s, I worked on a satellite for the JPL that was for Japan. Both of us came to the conclusion the most remarkable about NASA was that the people doing the work still managed to get amazing things done.

      By contrast, Elon Musk is a private sector guy. He hires who he wants and does what he wants. Reusable rockets aren't a new idea; it's just that nobody has had the single-minded drive to do all the work required to make them work. NASA flew a reusable rocket called the DC-X in the early '90s. It flew a couple of missions and they dropped it.

      Elon Musk had the idea that he would put up payloads for hire and work on being able to land them for reuse. That was company R&D, sure, but the rocket was going up and falling back down anyway, put a drone ship out in the ocean and try to land on it. It took them years of trying but now they're light years ahead of the competition. There's a report that this week there will be a launch from Vandenberg that will be the 11th flight of the booster. Nobody else on Earth is close to that.

      The main difference between Elon Musk and NASA is Musk is driven for this goal he sees (establishing a civilization on Mars) and thinks he can get it. The next difference is that if customers are willing to pay for launches and investors are willing to invest in the stocks, keeping the doors open, they'll keep working toward his goal. A new political situation can kill off any NASA project or redirect it - although you'd never guess that by looking at the Space Launch System or the James Webb Space Telescope. Both of those are more than a decade late and billions of dollars over budget. I really hope the JWST works and has a long, productive, life. SLS is obsolete already.