Apr 17, 2020 05:29 PM
(This post was last modified: Apr 17, 2020 06:16 PM by Yazata.)
Mary reports that the SN4 tank section is stacked.
https://twitter.com/BocaChicaGal/status/...5283999744
In Mary's photo in the tweet above, note the nose-cone. Unclear if it will go atop SN4 or is waiting for a later prototype.
And note the top dome, sleeved in rings, that's appeared to the nose cone's left. So pieces of SN5 are starting to appear. Spaceship mass-production! SN5's common bulkhead and thrust dome are still inside the giant tents.
As to what Elon plans to do with SN4, provided that it passes the pressurization and static fire tests (not as simple as it sounds), he says that SN4 (and perhaps SN5) won't get fins, and will only hop, Hoppy-style. There are lots of things to test doing that, including running and throttling three raptor engines at once, gimballing them in unison, all the control systems involved in that (flight computer, comms etc.) and proving the untested autogeneous pressurization system that uses bleed gases from the engines to pressurize the tanks.
As for the fins, Elon says that they are being redesigned... again. (They make all this stuff up as they go and are never satisfied.) The fins that appear on SN5 or SN6 will look different than the ones we've seen, will have different actuators, and will have different aerodynamics. (The engineers are going berserk trying to guess what the changes will be.)
https://twitter.com/elonmusk/status/1250613503888519168
Meanwhile at the launch area, they are busily preparing the test stand, reinstalling the hydraulic rams that will simulate engine thrust during the tank pressure tests. The framework supporting the previous ones broke when suddenly exposed to liquid nitrogen.
Tankers have been delivering liquid nitrogen.
Still no road closures announced.
https://twitter.com/BocaChicaGal/status/...5283999744
In Mary's photo in the tweet above, note the nose-cone. Unclear if it will go atop SN4 or is waiting for a later prototype.
And note the top dome, sleeved in rings, that's appeared to the nose cone's left. So pieces of SN5 are starting to appear. Spaceship mass-production! SN5's common bulkhead and thrust dome are still inside the giant tents.
As to what Elon plans to do with SN4, provided that it passes the pressurization and static fire tests (not as simple as it sounds), he says that SN4 (and perhaps SN5) won't get fins, and will only hop, Hoppy-style. There are lots of things to test doing that, including running and throttling three raptor engines at once, gimballing them in unison, all the control systems involved in that (flight computer, comms etc.) and proving the untested autogeneous pressurization system that uses bleed gases from the engines to pressurize the tanks.
As for the fins, Elon says that they are being redesigned... again. (They make all this stuff up as they go and are never satisfied.) The fins that appear on SN5 or SN6 will look different than the ones we've seen, will have different actuators, and will have different aerodynamics. (The engineers are going berserk trying to guess what the changes will be.)
https://twitter.com/elonmusk/status/1250613503888519168
Meanwhile at the launch area, they are busily preparing the test stand, reinstalling the hydraulic rams that will simulate engine thrust during the tank pressure tests. The framework supporting the previous ones broke when suddenly exposed to liquid nitrogen.
Tankers have been delivering liquid nitrogen.
Still no road closures announced.
![[Image: EV6tzYlX0AIcfeP?format=jpg&name=4096x4096]](https://pbs.twimg.com/media/EV6tzYlX0AIcfeP?format=jpg&name=4096x4096)
![[Image: EV79hoiWkAAvtB5?format=jpg&name=small]](https://pbs.twimg.com/media/EV79hoiWkAAvtB5?format=jpg&name=small)
![[Image: EWT20B5WkAENZlh?format=jpg&name=large]](https://pbs.twimg.com/media/EWT20B5WkAENZlh?format=jpg&name=large)
![[Image: EWbw9O1WAAAUs4R?format=jpg]](https://pbs.twimg.com/media/EWbw9O1WAAAUs4R?format=jpg)