If you've been watching the daily or 24/7 feeds and news reports from SpaceX Starbase at Boca Chica, you'll have heard some of this. Bottom line, like the headline, it's starting to look like the emphasis at Boca Chica is going to get back to testing their orbital Starship and Super Heavy. It's looking like it could be starting this week.
One of the bigger items in the news feeds this week is that the giant crane on lease for the last few months, the one the Lab Padre people nicknamed Kong, is apparently being decommissioned and returned to whomever they leased it from. That's another signal that the major heavy lifting to complete the launch complex is over. My first mention of Kong appears to have been May 21 of '21.
Teslarati's Eric Ralph talks about the various things that have been going on with both Booster 4 and Starship 20 while the work around the launch complex dominated the schedules.
B4 has had several Raptors removed and replaced. Of course, we don't know why.
Aside from removing around a third to half of Super Heavy’s 29 Raptors, SpaceX also began slowly but surely installing parts of a steel heatshield designed to protect those engines during ground testing, ascent, and reentry. Newer Raptors have also been trickling from Starbase’s build site to the launch pad for installation on the booster and more engines will likely be (re)installed as heatshield installation progresses.
Perhaps the most unusual part of recent Super Heavy B4 work is the apparent application of some kind of foam around several racks of pressure vessels (COPVs), hydraulic manifolds, and umbilical connections installed around the booster’s base. Those racks will eventually be enclosed inside steel ‘aerocovers’ already staged beside Super Heavy. A number of Twitter users believe that the foam being selectively applied is for acoustic deadening – meant to protect sensitive electronics, valves, and computers from the brutal environment Super Heavy itself will produce at liftoff and during ground testing.
The booster aerocovers are highlighted in the red rectangle at left. For scale comparison, notice the two concrete mixer trucks just to the left of the top of B4 in this view looking down, from RGV Aerial Photography.
Starship S20 has had less going on than Booster B4; it appears that since the recent static fire tests, they've gone back to the full complement of three sea-level Raptor Center (RC) engines and three Raptor vacuum (Rvac) engines.
Barely a full day after that successful back-to-back static fire test, SpaceX rolled two more sea-level Raptors to the suborbital pad and installed them on Ship 20. Another unusual week of downtime later and, on October 28th, SpaceX has rolled two more Raptor Vacuum engines from the build site to the launch pad and staged them beside Starship. Once installed, Starship S20 will, for the second time, be fully outfitted with six Raptors. Having already fired up two of those engines without needing either replaced, though, there’s a decent chance that all six will actually be used before Ship 20’s next bout of engine removal/installation deja vu.
Base of S20 back in August, the first time it had all six engines installed. Elon Musk photo.
There are things to be tested here that have never been tested before. For openers, no Starship has been tested with all six engines. In real life, they aren't used together since the Rvacs are optimized for operation in a vacuum (or close) while the Rc engines are optimized for nearly sea level. The Rvacs will be used when the booster drops away and the upper stage is working toward orbit; the Rc engines will be used for the Starship's landing. They can test all six, though, since they're ensuring all the plumbing, valves and all that hardware is actually working.
Beyond that, the booster will have 29 Rc engines. They've never lit that many engines at one time. SpaceX hasn't even performed a full Super Heavy wet dress rehearsal (WDR; filling the booster's tanks and performing a launch countdown) or fire up more than three Raptors on a booster or ship prototype.
Right now, the only road closure scheduled on the Cameron County website is for most of the day Monday. I think that's probably to move Kong the crane back to the shipyard area. When they issue an over pressure notice, that's when there's a good chance it's going to get interesting.
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I just wonder what that thing will sound like with Twenty-Nine
ReplyDeleteengines going full-tilt
One of the reasons people are questioning as to what type of sound suppression system SpaceX will use.
DeleteThis might be a fun 'playing with numbers' experiment. A quick search for sound pressure level of a space shuttle launch turns up a source that says 196 dB for one SRB. Seems reasonable to add 3 dB for a second SRB, but then I run out of data (so far!). Since Starship will be bigger than a Saturn V, and have around four times the thrust of a Shuttle at liftoff, I think that the SPL has to be at least 200 dB. Somewhere else I found a quote that says, "One of the loudest sounds ever recorded was NASA's Saturn V rocket, which registered 204 decibels." Super Heavy will be more powerful than that.
DeleteI think the shuttle launches had a one mile keep out zone in which not even cleared and trained people could enter, and somewhere inside that zone the sound pressure would kill.
Since the houses of Boca Chica village seem to be less than a mile away, I wonder if any windows will survive.
I had some Boeing Buddies that worked on the shuttle program. There were dead birds and gators from the sound pressure. One of them told me they'd find the explosive bolts from the hold-down clamps a quarter mile away from the pad.
DeleteWonder if they're upgrading their water deluge system?
SpaceX is assembling a Liebher 1100 decked out with the SpaceX logo so their heavy lifting needs will be fulfilled by their own(ed) machine, rather than a leased one.
ReplyDeleteIt looks like the only thing holding SpaceX back is the FAA.
my goodness, thanks for the comparison. those skirts are huge. It's hard for me to grasp how huge this craft must be fully assembled. The pictures don't usually help much.
ReplyDelete