Wednesday, October 12, 2022

Looks Like Starbase is Getting Active Again

In the last 24 hours, SpaceX at Boca Chica stacked the full Starship combination of booster 7 and ship 24, the pair that has been leading speculation for the first pair to attempt orbit.  

Around sunset on October 11th, SpaceX had better luck on its third attempt and was able to move the arms into place under Ship 24. Weighing 100 tons or more (~220,000+ lb) and measuring nine meters (~30 ft) wide and ~50 meters (~165 ft) tall, the Starship was then slowly lifted about 80 meters (~250 ft) off the ground, translated over to Booster 7, and lowered on top of the 69-meter-tall (~225 ft) first stage. After about two more hours of robotically tweaking their positions, the two Starship stages were finally secured together. With the arms still attached to Ship 24, SpaceX workers were able to approach the rocket and prepare to connect the swing arm’s quick-disconnect umbilical to Starship. 

Not quite a month ago, September 19th, Booster 7 had the first seven engine static firing a booster has ever had.  In the followup to that test, Elon Musk tweeted this:

"In a few weeks?"  Seems to be right on schedule.  I never saw any testing of booster 8, though.

Ten days before that booster test, Ship 24 did a static firing of all six of its engines at once, a condition that I haven't seen referred to as something that will be a regular part of missions.  There are three Raptor Vacuum engines and three sea level Raptors.  The vacuum engines will be used during ascent after the booster stage drops away, and the sea level engines will be used for landing.  As I understand it.

A full 33 engine static firing is still probably weeks away, as a guess.  There was a road closure today and the expectations among watchers was that they'd do some overall cryogenic testing to ensure nothing was behaving badly, but no tests were done today.  Instead, what was done was ship 24 was lifted off the booster for some reason and then put back.  Since I started this paragraph with speculation, I'll continue that way.  Starship watchers seem to think they won't go from firing seven engines directly to 33.  Unless there's some hardware-specific reason to group certain engines together, they'll progress from seven to some intermediate number and then probably to 20, the outer ring of Raptors that don't need to gimbal (to steer the booster).  The remaining 13 engines are all of the engines that gimbal; perhaps they'll get one test by themselves.  There will undoubtedly be some days between tests, more if anything needs repairs.

The full stack wet dress rehearsal that Musk mentions has been done at various levels of the prototypes, but with the most powerful rocket ever built, the scale is mind boggling.  The prototypes will be simultaneously loaded with around 5000 tons (~11M lb) of liquid oxygen and methane propellant and then run through a launch countdown, stopping just short of igniting the engines.  Does that happen before the 33 engine static firing?  My guess is yes, and Eric Ralph at Teslarati says the same thing.  

If the wet dress rehearsal goes to plan, SpaceX will then attempt to simultaneously ignite all 33 of the Raptor engines installed on Super Heavy B7, almost certainly making it the most powerful liquid rocket ever tested. Even if all 33 engines never reach more than 60% of their maximum thrust of 230 tons (~510,000 lbf), they will likely break the Soviet N-1 rocket’s record of 4500 tons of thrust (~10M lbf) at sea level. It would also be the most rocket engines ever simultaneously ignited on one vehicle. SpaceX will be pushing the envelope by several measures, and success is far from guaranteed.

The single most common question in any chat group I see about Starbase is often abbreviated to just "wenlaunch?"  I think it's a bit much to think that SpaceX won't have to repair anything or reiterate some aspect of the design, especially since that appears to be their primary method of development.  Still, if everything goes perfectly, we could see the first orbital attempt in November, even possibly before the Artemis/SLS window in mid-late November.  If they need to repair or change things, that date slides out.  It seems very likely Starship will launch before too far into '23. 

Fully stacked Ship 24 and booster 7, Tweeted by Elon Musk at 8:10 PM EDT Wednesday evening.

EDIT 10-13-22 0808 EDT:  Corrected typo (brain fart?) of "Starship will launch before too far into '24"  to say '23, as intended.



9 comments:

  1. Yea, I'm going full wenlaunch too.

    I not old enough to have seen the first space race, but this one has been very exciting.

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  2. "It seems very likely Starship will launch before too far into '24." Did you mean '23?

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  3. WoW.....just WOW.

    @Ratus - They were exciting days, indeed. My Mom let me stay home from school to watch the Shepard, Grissom, and Glenn launches. I cried when I heard ...The Eagle Has Landed...

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    1. I was raised in SouthFL in the late'70s and '80s, so NASA and the Cape Canaveral area was a destination for summer vacations a couple of times.

      Jetty Park Campground was awesome as a kid. Wasn't ever there for a launch, but still fun.

      I think that the visitor center/museum was even free back then.

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    2. Ha. Went to the neighbor's house to watch the Apollo launches and splashdowns because they had a color tv (one of those console things with a high-fi and a bar in it.) Watched the Moon Landing at home because they were in black&white and we had a BW television.

      And had a GI Joe in a Mercury capsule, complete with Mercury space suit.

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    3. I was a kid living on an American base in Germany when Shepard flew. Following the flight our elementary school had all of the students write a letter to NASA. They then sent it off. A couple of months later (in the days when Airmail cost extra) we received individual replies. But I was irked that I received an autographed picture - not of Shepard but some guy named John Glenn. I'm sure it's around somewhere still.

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    4. I'm probably about midway between Anon 0704 and Ratus in age. I would have been seven for Alan Shepard's flight in '61. Growing up in South Miami, they herded us to the cafetorium (the only TVs in the school) for Shepard's flight and then Glenn's. After that they kinda had to slow down and not interrupt classes as much.

      Vacationed in Cocoa Beach, toured the KSC, but never saw a launch until the shuttle program. Got to watch a couple of launches from on the base itself once Mrs. Graybeard started working up there.

      The latest space program with its mix of hi-tech approaches and companies competing with each other is captivating. I still haven't gotten tired of watching SpaceX land boosters, and when they return to the Cape, we get the sonic booms we used to get from shuttle landings. That's cool, too.

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  4. Beans,
    Got you beat. I had the complete set of Major Matt Mason.

    Saw Apollo 11 in a Howard Johnson's in south central Pennsylvania.

    Watched every moonwalk.

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