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Appears that last night they did the ambient temperature nitrogen gas pressure test. Then they apparently put some unpressurized liquid nitrogen in the tanks, presumably to cryo-harden the welds. Full-on cryo pressure test is on for tonight.

Elon says, "SN4 passed ambient pressure test.

Aiming for cryo pressure test tonight."

https://twitter.com/elonmusk/status/1254431839399411718

https://en.wikipedia.org/wiki/Cryogenic_hardening

Somebody asked if SN4 will fly to 20km or just 150m, and when.

Elon says, "150m

Physically ready in a few weeks.

Approvals may take longer."

Chris Bergin of NSF comments, "Fingers and toes crossed for Starship SN4 tonight.

Elon noted the ambient pressure test received a pass mark last night. The cryo pressure test is what sent Mk.1, SN1 and SN3 Starships to Sto-vo-kor."

Elon replies, "It's a little dicey tbh. Thrust dome is being redesigned. Current one has four separate layers of steel in some places!"

Roadblocks have just gone up. Labpadre's stream showed sheriffs cars with flashing lights. There are still people and vehicles at the pad though. SpaceX told Michael Baylor that they are doing final checkouts and everything is on track, so far.



Edit:9:27 PM CDT Pad clear.

Edit: 9:50 PM CDT small quantity of vapor spotted under the launch mount. Mary reports distinctive sound of the pumps they use to move fluids around in the tank farm. Frost has started to appear on the CH4 tank.

Edit: 10:00 PM CDT More abundant venting from LOX tank relief valve. Distinct line of frost on the bottom of the LOX tank.

Edit: 10:51 PM CDT Elon posted a short video clip up SN4's skirt, showing the thrust dome/business end plus the hydraulic rams, with the words "Snowing in Texas"

https://twitter.com/elonmusk/status/1254618912785915906



Edit: 11:10 PM CDT furious venting and growing frost. Nomadd reports that the pump sounds that Mary reported earlier are constant now. Lots of venting in the tank farm too.

Edit: 11:46 PM CDT Elon says that SN4 has passed the Cryo Proof Test

https://twitter.com/elonmusk/status/1254632509863866368

(Apr 27, 2020 02:27 AM)Yazata Wrote: [ -> ]Roadblocks have just gone up. Labpadre's stream showed sheriffs cars with flashing lights. There are still people and vehicles at the pad though. SpaceX told Michael Baylor that they are doing final checkouts and everything is on track, so far.

Would be nice to see a can again that doesn't pop its top or implode.

(Apr 27, 2020 03:34 AM)C C Wrote: [ -> ]Would be nice to see a can again that doesn't pop its top or implode.

It's still standing. So I guess that we can say that they failed to blow it up like the others.

Elon admits that it was a pretty wimpy test, only up to 4.9 bar. A modest hurdle, but sufficient for flight.

This morning they disassembled the hydraulic rams at SN4's base. The plan seems to be to conduct a static fire late in the week.

Elon says that the new plan is for SN4 to only get one raptor instead of the anticipated three. SN5 will get three, and fins, and a nose, the full aerodynamic treatment. They anticipate flying SN4 with that single raptor merely on a modest little Hoppy-style hop as a systems check. That might be a month off, since while the vehicle will be ready, the necessary government approvals probably won't be.

Live view of SN4. As Dr. Frankenstein said It's alive!!

Looks like the static fire might be Friday night. Maybe Saturday or Sunday. Road closures announced for all three days and temporary flight restrictions issued.

A single raptor engine was observed being trucked down the road to the launch site. Labpadre says that it's currently sitting underneath SN4 but it doesn't appear to have been integrated with the tank yet.

Liquid methane tankers arrived today and the flare stack is lit once again, something that we haven't seen since Hoppy's flight about eight months ago.

In case we forget what this is all about, here's a very good render by Alex Delderfield (an Australian video-game developer) showing a much more mature Starship on the launch pad in a year or two. It shows a cleaner build with the nose and the flipperflappers installed. It also shows Elon's giant window in the front. I don't expect the giant window to appear for a long time (if ever) since it will only be in the manned versions and those will only appear after lots of unmanned test flights have proved the vehicle. I also expect that the window will present too many engineering challenges and will eventually be removed from the design in favor of smaller windows.

https://twitter.com/Alex_ADEdge/status/1...4355027973



And here's a Falcon that plopped itself down in front of one of Labpadre's telescopic cameras at South Padre Island (about six miles from Boca Chica). It says don't forget me! I'm gonna do something amazing on May 27!

https://twitter.com/LabPadre/status/1254955191008481281

NASA just announced selection of three entries to receive an initial NASA contract to design a manned lunar lander to transport people and cargo back and forth from NASA's planned Gateway space station in lunar orbit to the Moon's surface.

"SpaceX has been selected to develop a lunar optimized Starship to transport crew between lunar orbit and the surface of the Moon as part of NASA's Artemis program!"

https://twitter.com/SpaceX/status/1255907211533901825

https://www.nasa.gov/feature/nasa-select...an-landers

https://arstechnica.com/science/2020/04/...-starship/

The other winning entries were Jeff Bezos' less ambitious Apollo-style Blue Moon lunar lander and for Dynetics' interesting but less ambitious Alpaca lander.



Blue's getting paid $579 million for the initial funding. Dynetics is getting $253 million. And SpaceX $135 million.

Ars Technica explains the differences in contract sizes this way: "Bridenstine said the individual award amounts do not reflect a ranking or preference on the space agency's behalf. Rather, he said, the awards are based upon the amounts requested by each of the three teams and the scope of work they proposed to complete over the next 10 months. "Some people might look at the dollar amounts and think we’re playing favorites," he said. "And we’re really, really not." "

So NASA's going to look at progress in ten months and then award additional funding based on how well things are coming along. (This is where Elon's frantic pace might pay off better than creeping along at government contractor speed.

NASA seems to acknowledge that Starship is something of a stretch. It's far more risky than the other two options, but it offers vastly more upside if it succeeds. Ars Technica quotes Bridenstine:

"SpaceX is really good at flying and testing—and failing and fixing," he said. "People are going to look at this and say, 'My goodness, we just saw Starship blow up again. Why are you giving them a contract?' The answer is because SpaceX is really good at iteratively testing and fixing. This is not new to them. They have a design here that, if successful, is going to be transformational. It’s going to drive down costs and it’s going to increase access, and it’s going to enable commercial activities that historically we’ve only dreamed about. I fully believe that Elon Musk is going to be successful. He is focused like a laser on these activities."

Which at the very least outs Bridenstine as a space-geek... He personally seems to like the sexiest Sci-Fi option, with two safer options if it doesn't pan out.

And it's conceivable that SpaceX hiring Bill Gerstenmaier might be paying some dividends. Where NASA used to consider Starship to be Elon's crazy folly, now they are starting to take it seriously.

NASA describes the SpaceX plan this way, "Several Starships serve distinct purposes in enabling human landing missions, each based on the common Starship design. A propellant storage Starship will park in low-Earth orbit to be supplied by tanker Starships. The human-rated Starship will launch to the storage unit in Earth orbit, fuel up, and continue to lunar orbit."

SpaceX renders of the newly announced lunar optimized Starship



No, those aren't spotlights. They are engines, Superdraco-style rocket thrusters. The Moon's gravity is so low that it doesn't take much rocket thrust to land and take off there. The engines (three sets of three) are mounted high up to minimize kicking up lunar dust and rocks.



Blue's far less risky entry (NASA graphic)



Dynetics' Alpaca lander (NASA image)

The loudspeakers that had been attached to the bottom of Hoppy suddenly disappeared again without ever being used. (I really liked the fantasy of Elon playing Ride of the Valkyries as new rockets rolled out to the pads.)

But... Hoppy has regained its voice. Not only that, now it has eyes. In the photo below, there are several cameras apparently pointed at the launch pad. Plus a couple of loudspeakers below. Nomadd reports that they are installing more cameras, apparently pointed at the landing pad.

(Photo by NSF member and Boca Chica resident Nomadd)

https://forum.nasaspaceflight.com/assets...757443.jpg

And Hoppy spoke! Late this afternoon it was heard announcing that the pad area was being cleared for tonight's "wet dry run". LOX and liquid methane will be loaded into SN4 which will be pressurized, and (perhaps, not sure) the preburners and turbopumps will be spun up, all without lighting the Raptor engine. That ignition is coming in the middle of next week when a static fire is planned. With fuel and oxidizer in tonight's mix, instead of relatively inert liquid nitrogen, tonight's explosion hazard is multiplied.

After Hoppy told everyone at the launch area to get out, the local sheriffs put up their roadblock and closed the road. (Photo by SPadre) In the photo they are letting workers' cars out but not letting anyone go in.



And local resident Nomadd reports that the sheriffs went through Boca Chica village handing out these leaflets warning them that SpaceX will be conducting "spaceflight activities" between 3 AM and 4 AM their time (CDT) Sunday that could result in an "overpressure event" (engineering-speak for "explosion") capable of blowing in windows a mile away in the Village. So they are warned that a siren will sound 10 minutes before the explosion hazard and that they must leave their homes and go outside. At 3AM! With 10 minutes notice! Of course Mary and Nomadd will already be out there with a whole team this time streaming and photographing whatever happens.



Lab Padre's livestream is here



AND... NSF is teaming with Mary to do a livestream which will go live 10 PM CDT here



Spadre had another stream going but it was too close and got chased off by the cops. It's running again from further away here

The wet dry run didn't happen last night. Dunno why. Presumably they will try again tonight, their backup day. Streams same as last night.

There was a bit of excitement last night though. They were moving liquid methane around and the flare stack got very active. Big flames. Then it appears that liquid methane started coming out of the stack. (Not supposed to happen.) There was some concern among the spectators that a grass fire might be triggered, but the ground had been cleared and that didn't happen.

As for Hoppy's new voice, here's a short twitter clip of it ordering non-essential personnel off the launch site. Hoppy has a Texas accent, which shouldn't be surprising seeing as how it was born in Texas.

https://twitter.com/SpacePadreIsle/statu...8329249793

Twitter video clip of the flare stack shenanigans (Another Elon 'not a flamethrower'.)

https://twitter.com/NASASpaceflight/stat...8577394688

A single police car has planted itself in the road with its lights on and is turning around occasional vehicles headed for the beach. Then a parade of cars came by heading in the other direction away from the launch area. I'm guessing that they were launch area workers. Hoppy must have Spoken. But the pad still isn't clear and workers are visible on a boom lift next to the cylinder.

Edit: Pad is now clear.

Edit 2: 12:25 AM CDT Scott Manley is on the NSF stream. Nomadd reports sounds of pumps in the tank farm. Small amount of venting on the CH4 fuel tank. Perhaps some slight frosting. Condensation coming out of the bottom, so they are loading LOX too.

Edit3: Elon's watching NSF's stream. https://twitter.com/elonmusk/status/1257182201130758146 (MST3K!! )

Edit4: Tim Dodd's on the stream. LOX loading.

Elon posted this photo taken up SN4's skirt showing its private parts, including a single Raptor mounted slightly off-center. (Because the thrust dome is designed to fit three engines.)



https://twitter.com/elonmusk/status/125715219473162240

NSF's live-stream featuring beautiful clear hi-def video by Mary



LabPadre's stream



SPadre's stream