Scivillage.com Casual Discussion Science Forum

Activity at the Boca Chica launch site today.

There's no notice of road closures on the Cameron County website. Closures are scheduled for tomorrow.

http://www.co.cameron.tx.us/wp/space-x/

But... Mary reports that the road is indeed closed as we speak. Tankers full of liquid nitrogen arrived earlier and lots of venting was coming from the tank farm area. It's quieted down now.

Mournful Edit:

THE BOCA CHICA STARSHIP JUST EXPLODED. Not a big fiery chemical explosion, but rather a pressure-burst explosion. Both the top and bottom bulkheads blew out and the thing looks like a total loss.

Videos of the explosion here (the second shows the top bulkhead coming back down after flying hundreds of feet high):

https://twitter.com/NASASpaceflight/stat...7589303296

https://twitter.com/NASASpaceflight/stat...3049890821

The second of the photos below (stills from LabPadre's stream) shows the top bulkhead flying off, then the bottom blows out in the next two.

The engineers note that there wasn't any overpressure venting before it blew. So it apparently hadn't reached an internal pressure that would activate them.

Maybe bad welds. If so, that could indicate a fundamental weakness in the 'build spaceships out in a field' model.

The SpaceX philosophy is "test till it breaks". Well... I suspect that this one broke long before they anticipated it would.



Tim Dodd asked if they will try to repair this Mk.1 Starship or move on directly to Mk.3 (the next Boca ship, Mk.2 is the one at Cocoa with Mk.4 its successor).

Elon replies that they will go directly to Mk.3. So Boca Chica is going to start over again at zero making a new and hopefully much improved vehicle. Elon says that there are lots of design changes in that one. (They kind of make it all up as they go, designers still designing even as they build prototypes.) This version served its purpose as what Elon calls a "manufacturing pathfinder", but the flight versions will be significantly different.

https://twitter.com/elonmusk/status/1197271943180771329

Here's some instant journalism on the Starship failure

https://www.nasaspaceflight.com/2019/11/...enic-test/

Another video that shows the explosion starting in the upper right, part of the raceway fairings coming off as shrapnel, then a couple of rings splitting off and flying skywards, carrying the top tank bulkhead. Then the explosion is visible coming out the the bottom of the Cylinder, indicating that both the common bulkhead between the fuel and oxidizer tanks, and the bottom bulkhead had blown out.

They can probably salvage the fins and their actuators, but that's probably about it.

LabPadre thinks that the top bulkhead is currently sitting on the road, or near to it.



Here's what SpaceX's PR people told CNBC. Looks to me like they are trying to put lipstick on a pig.

An oversized corn-liquor still exploding today to go along with the confident spokesperson talk earlier that might have sounded like moonshine to some.

New fences were erected some time ago around a large area next to the launch area. Then stakes were seen in the ground and lots of equipment subsequently moved in to push dirt around. The mystery of what's happening becomes a little clearer with this new sign that's appeared on the fence near a gate. (Photo by Alex Balderas)



Of course, there's been no clear and obvious sign yet of a Superheavy booster beginning construction at Boca (or anywhere for that matter). There's lots of brave talk about orbital flights though, and these would seem to require the Superheavy. If a Starship makes it to orbit under its own power without the booster, it probably wouldn't have enough fuel to return and the vehicle would be lost. Despite yesterday, they can't just throw their spaceships away without SX burning cash at a rate it can't sustain. Besides, putting an early prototype Starship in orbit would probably be largely to experiment with reentry, so perfecting its ability to come back would be a big part of the point of putting it up there. So I was always skeptical about Elon's hugely optimistic projections of when they would try for orbit.

The loss of the Mark 1 prototype might not delay Starship flights atop the Superheavy, since Mk.1 was never intended to do that. But Mk.3 might be. For one thing, it will have 3 Raptor vacuum engines (R-vac) along with its 3 conventional sea-level Raptors for a total of six engines. (They are the same engine essentially, with different bell nozzles.) That's the eventual production layout as presently envisioned. Presumably, if they are going to put vacuum engines on the Mk.3 Starship, it's eventually headed for vacuum.

But despite SX's talk yesterday (only after the loss of Mk.1) about their having decided prior to the accident not to fly Mk.1, all indications are that they intended to fly it to about 60,000 feet and have it skydive back sideways to test its control and aerodynamics and its proposed last-seconds 90 degree pitch-up and vertical landing. Even a crudely built prototype not suitable for space travel might be useful for that. They were working feverishly on it (night and day) up till yesterday and it's hard to imagine them doing that if they didn't intend to use it for something important. Of course there was lots of talk about it only making that one flight and then being retired like Hoppy. I suspect that might have been the plan.

It's the Mk.2 in Cocoa that seems to have slowed almost to a halt, so I wouldn't be surprised if they no longer intended to fly that one because it was too committed to an outmoded design and Mk.1 was expected to give them all the engineering data they expected to get from that design. It will be interesting to see if the pace picks up again in Florida, completing Mk.2 at least for the landing experiment, now that Mk.1 is off the table.

The welds on the outside of the Mk 1 didn't look as good as Hoppy's. I get the impression this is a single skin pressure vessel so all welds need to be perfect every time. I suspect NASA would have spent months checking for weld defects. The crossed fingers approach may not be as good as we hoped,

There are rumors floating around (nothing more than that) that suggest that the Cylinder was accidently pressurized more than intended, due to some software screw-up or something. That's consistent with the fact that no pressure relief venting was observed. Of course there should have been passive pressure relief measures as well, such as burst-disks. Another rumor going around (nothing more than that) suggests that they overpressured on purpose in a test-to-destruction. I'm a bit skeptical about both of those.

The engineers are currently trying to figure out what the internal pressure of the tank was when it blew, based on how high the upper bulkhead flew and its mass along with the mass of the rings that came off with it. That should enable calculating the force that launched it, which should enable calculating the pressure given the area of the bulkhead dome.

The fact that it flew so high, something like 400 hundred feet (comparable to Hoppy's flight), suggests that the pressure was pretty high. The Cylinder made an excellent pop-gun.

Summary of what I take to be some of the better ideas swirling around this thing:

One idea is that the decision had been made not to fly this Mk.1 Starship even before the test. The SpaceX PR statement to CNBC above says as much. Not clear why.

The virtual cessation of work on the Florida Mk.2 prototype several weeks prior to these events does suggest that SpaceX had decided to take a different direction.

Several ideas regarding why:

One is that the Boca structure at least was deemed too weak to survive the landing maneuvers. (And definitely reentry from orbit.) It was very crudely constructed, out in a field. So, the next question goes, if they were going to scrap it without flying it, why did they subject it to the pressure test? One speculation there is that they were testing the plumbing more than anything, the pumps that load propellant, the ground support equipment and so on. The ability of the tank to withstand the pressure is only one part of it, and Elon and the PR person didn't sound all that surprised that aspect failed.

Another idea going around is that they were concerned about Mk.1's growing weight. This is basically an empty beer can with its walls expected to bear all the loads. Speculation is that the designers decided that given the many forces it's expected to withstand, from rocket engines to forces from the fins, making it strong enough would mean making the walls even thicker, which would mean making it too heavy. So (the speculation goes) they decided that a thinner wall design and a new internal structural framework would end up being lighter in the long run. And if they are going to a new design, it would be wasteful to continue work on examples of the old design.

But... they were certainly working feverishly on the Boca Mk.1 prototype right up till the end. Lots of that work seemed to involve flight systems (thrusters, raceways, fin actuators) that wouldn't be needed if they knew that they wouldn't be flying it. So it looked to me like they still intended to fly it, if only to experiment with the unorthodox landing method, until the moment it blew up.

But... some change of course was definitely underway before this unfortunate explosion. The Cocoa Starship construction had basically halted a couple of weeks prior. Then on Monday (the day before the ill-fated Boca test, the Cocoa crew was observed cutting up some of the rings that they had constructed, presumably in anticipation of the follow-on Mk.4 version. Nobody is sure what to make of that. The Cocoa parking lot is still full, so workers are doing something that we can't see.

Another thing that I wouldn't personally be surprised seeing is SpaceX packing up their Cocoa construction yard entirely and moving their operations onto the Kennedy Space Center grounds. In Cocoa they have to move their huge spaceships through city streets, at KSC they would have a straight shot at the pads. Boeing and Blue Origin already have manufacturing facilities on KSC grounds, so I wouldn't be surprised to see SpaceX joining them. I believe that land has already been allocated for it.

Here's a very interesting video that shows SpaceX's activities at Roberts Road at the Kennedy Space Center. New structures going up, rolls of stainless steel being delivered, and road improvements along the route from Roberts Road to the launch pads. A large new launch mount is under construction at the pad allocated to SX, larger than the one at Boca. Felix, the guy who made this video, agrees with my idea in my last post in thinking that SX will eventually be closing their Cocoa construction yard and moving operations to Roberts Road. Interestingly portable generators have been packed up in Cocoa and portable generators have appeared at RR. Relix expects to see a parade of trucks carrying stuff from Cocoa to RR.

The video also includes interesting photos of what highly-secretive Blue Origin is doing at Kennedy Space Center. A very large rocket construction building is very obviously under construction and it's assumed that their large new (Superheavy-sized) reusable New Glenn rocket will be manufactured there. They are also doing work on a Blue Origin launchpad.

https://www.youtube.com/watch?time_conti...e=emb_logo

Two new upstart companies built around reusable rocketry, reigniting something of the old 1960's space enthusiasm. Suddenly the old vision of manned space exploration, Moon bases and Mars expeditions might actually become affordable, practical and doable. At the very least, they (SX at this point) are cornering the market on commercial satellite launches. Traditional aerospace everywhere is choking and wheezing on New Space's dust. And some of them aren't very happy about it. (Lots of Schadenfreude from Boeing employees at Starship's recent misfortune.)

It looks like they are moving things from Cocoa to Roberts Road (on the KSC grounds). The two circular 'M' base structures went today on flatbed truck trailers (one pink and one blue, barely visible in the photo on the tweet). The 'M' bases (it should be obvious why people call them that) are circular and at 30 feet diameter they are definitely over-sized loads and the police gave them an escort to facilitate moving them down the busy freeway leading to Cape Canaveral. (They are nothing compared to a full-size Starship, which is probably a big part of why SpaceX are changing their east coast location to be closer to the pad.

https://twitter.com/John_Winkopp/status/...8135773185

What appears to be a very recent rather low quality satellite photograph of SpaceX Roberts Road. It shows some structures, some of them probably the big metal framework tent structures that SX likes (cheaper and easier to erect and take down). Notable is the dramatic road widening visible at the lower right. Perhaps a crawler-way to facilitate moving large rockets to the pads not far away. This was probably where they planned to build their Superheavy boosters all along, and now they seem to be consolidating all of their east coast construction here.

Plans submitted (and approved I believe) show that this site is destined to grow dramatically, extending off to the left in these photos with multiple new buildings. Apparently this won't just be for Starship/Superheavy but will be where SX refurbishes Falcon 9's, prepares Crew Dragons and has its Cape Canaveral offices. Don't know the time-frame for that, but things seem to be moving fast.



Here's a better satellite shot of the same site from September, showing the changes over just the last two months. There was one structure towards the top in September, now there are three. There were just what appeared to be shipping containers in the bottom section, now there seem to be blue-topped structures there. The road widening work is already underway. Here's SpaceX's application to the water management people for the road widening, from June of this year. Here's some twitter photos by Julia Bergeron from October, showing some white tents from a distance and the road widening work.

Photos are hard to get since you can't just walk around inside Kennedy Space Center taking pictures like Mary does in Boca Chica. Access is controlled.

The plot thickens. It seems that the tank bulkhead and the two Starship 'M' bases that left Cocoa didn't end up at Roberts Road as expected. Instead, they've been loaded onto one of the SpaceX's ocean-going ships, the Go Discovery in Port Canaveral. Are these items bound for Boca Chica? If they are, it suggests that SX might be giving up the simultaneous builds idea and concentrating their efforts on building the next ("Mk3") Starship in Boca. That adds support to the space nerd faction that speculates that the Florida cylinder is simply going to be scrapped right there in Coca rather than being moved to Roberts Road.

https://twitter.com/GregScott_photo/stat...7209109504

https://twitter.com/therealjonvh/status/...2051643392

Sunday morning edit:

Mary saw (and recorded) this Tesla on Saturday. It seems to be a new arrival in Boca Chica.