Wiki Super Heavy/Starship - General Development Discussion

[ecarfan]

This is not the first photo I’ve seen of a booster aft section, but it is one of the clearest. Blows my mind every time. 33 Raptors per booster. When Starship goes to 6 Raptor Vacs, along with the 3 sea-level Raptors, total engine count on the complete vehicle will be FORTY TWO. Which is really the perfect engine count.

 

[Electroman]

My non-scientific arm chair critic says, that is one too many boosters leading to one too many possible failure points.

FH had 27 boosters, but thats different. It was three independent F9s bolted together. More or like having a 3 engine freight train.

 

[Grendal]

My non-scientific arm chair critic says, that is one too many boosters leading to one too many possible failure points.

FH had 27 boosters, but thats different. It was three independent F9s bolted together. More or like having a 3 engine freight train.

Falcon 9 has nine engines. A lot of experts said that was too many and created more chances of failure. Only two Merlin engines have had a failure in 149 launches and 630 (650 maybe) engines. Neither engine failure led to a loss of the vehicle and neither led to a failure to reach orbit. I expect that SpaceX's strategy of the possibility of losing an engine but maintaining integrity is a sound one based on its history. Starship and Super Heavy are new vehicles and their robustness and integrity has yet to fully proven though.

 

[Cosmacelf]

Falcon 9 has nine engines. A lot of experts said that was too many and created more chances of failure. Only two Merlin engines have had a failure in 149 launches and 630 (650 maybe) engines. Neither engine failure led to a loss of the vehicle and neither led to a failure to reach orbit. I expect that SpaceX's strategy of the possibility of losing an engine but maintaining integrity is a sound one based on its history. Starship and Super Heavy are new vehicles and their robustness and integrity has yet to fully proven though.

Great point. Space X probably has hardware built into their rocket engines that does an emergency shut down should it see anything unusual going on. Like before an explosion occurs. Only spaceX can do this because they have redundant engine out capability.

 

[ecarfan]

My non-scientific arm chair critic says, that is one too many boosters leading to one too many possible failure points.

FH had 27 boosters, but thats different. It was three independent F9s bolted together. More or like having a 3 engine freight train.

By “boosters” I assume you mean “engines. The “booster” is the first stage.

@Grendal has provided the data to allay your concern, I would only add that with 33 engines per Super Heavy booster if one fails on ascent it doesn’t matter, and I bet that Starship will be able to land with just two out of three sea level engines. On Mars I’m not sure if the Raptor Vacuum or the sea level engines or both will be used for landing, but again if one fails landing is likely still achievable.

With SpaceX’s track record of rocket reliability, an engine failure is a very low probability.

 

[Grendal]

Elon, Raptors, and Starhip. Oh my.

 

[ecarfan]

That is a very helpful video and goes a long way towards clarifying the many different types of rocket engines. Raptor 2 is likely to be the best methalox design for quite awhile. It was interesting to learn that there are alternative types that offer some advantages to full flow stage combustion, but they have their own disadvantages as well.

As always, one needs to pick the right tool for the job.

 

[ecarfan]

New Ship QD has been installed on the OLT. NSF video here. And a surprise has shown up at Starbase; a sculpture based on the iconic New York City steelworkers on a skyscraper having lunch photo. Very cool! Here is the sculptors website. Also, note the amusing ”FOR SALE” sign at the Rocket Garden.

 

[Electroman]

Elon, Raptors, and Starhip. Oh my.

This guy is good.. very good.

 

[HVM]

 

[ecarfan]

That video is my first exposure to Zack Golden. I enjoyed his deadpan humor (“COVID test”, “cavity search”) but there is a fair amount of speculation in that video that is seemingly stated as fact. So I’m not going to take it too seriously.

Thousands (maybe millions) of SpaceX fans are watching the company build and test rockets out in the open, which is unprecedented. This naturally leads to a great deal of interest followed by speculation by people who are not aerospace engineers.

On another topic, I’m concerned that there is still no announcement about Boca Chica from the FAA.

 

[Electroman]

On another topic, I’m concerned that there is still no announcement about Boca Chica from the FAA.

They moved the decision by another month.

 

[ecarfan]

FAA delays environmental review of SpaceX’s Starship launches from Texas for a fourth time

Sigh…

 

[Electroman]

SpaceX is not ready for a launch anyway. So these delays have not impacted them yet.

 

[ecarfan]

B7 is out of the High Bay and was moved back to the launch pad area. Which means, I assume, that the damaged downcomer has been repaired. That would be a very impressive repair job.

It’s been just over a year since the successful flight and landing of S15. A long time between Starship test flights. Elon must be very frustrated. Will Super Heavy/Starship get to orbit before SLS? I bet he would love to make that happen.

 

[Grendal]

Elon must be very frustrated. Will Super Heavy/Starship get to orbit before SLS? I bet he would love to make that happen.

JMHO but I expect Elon could care less about SLS. He is focused on his goals and a fully reusable rocket. Each step of improvement for SH/Starship leads to more improvements. All of it takes time. More time than Elon would like it to be.

 

[ecarfan]

With B7 on the OLT, S24 has been stacked in the High Bay. Note: B7 has no grid fins, just holes where they would be mounted. I assumed that on the first launch that SpaceX would try to soft land it in the ocean and that grid fins would be needed for that. Either they aren’t needed and the holes will be sealed up, or they are going to be added later, or B7 isn’t going to be the first to launch. Do we know if it has all its engines mounted yet?

 

[mongo]

With B7 on the OLT, S24 has been stacked in the High Bay. Note: B7 has no grid fins, just holes where they would be mounted. I assumed that on the first launch that SpaceX would try to soft land it in the ocean and that grid fins would be needed for that. Either they aren’t needed and the holes will be sealed up, or they are going to be added later, or B7 isn’t going to be the first to launch. Do we know if it has all its engines mounted yet?

View attachment 802213

No engines mounted .
Think they are redoing cyro post downcomer repair.

 

[ecarfan]

No engines mounted .
Think they are redoing cyro post downcomer repair.

You mean repeating the cryo testing? That would make sense.

I wonder if the new downcomer is a different design or if they are going to revise the cryo testing procedure to try to reduce the pressure differential between the downcomer and the tank.

 

[mongo]

You mean repeating the cryo testing? That would make sense.

I wonder if the new downcomer is a different design or if they are going to revise the cryo testing procedure to try to reduce the pressure differential between the downcomer and the tank.

The one I saw pictures of looked the samish, but who knows what they did inside.
Spreadsheet calcs should have covered required pressurization/ strength. Guessing it was an operations or valve failure given the seam to the tank bottom was torn.