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Listen to my immediate reaction of the new report with @BBCAmos
👉https://tv.prime-intra.net/tv/cu/2023/03/27/336ca35d1c7bebffcd75ea0cfb1a45d0e3dbacba6fe1ef04a1d2ba105701ae7b943d41fcc3b9f4d9e01b5175100e37dc7910e47b71fd052b2349e1dda67dc4df_1679894694000_1.mp4
I want to know YOUR thoughts on #RevolutionSpace. Is this what you, as a European citizen, want for Europe? Comment below.
Full report can be found here: https://esa.int/Science_Exploration/Human_and_Robotic_Exploration/Independent_advisory_group_presents_report_on_European_space_revolution_to_ESA
Falcon 9 closes in on the port this morning
Starship (nee MCT) previously had a base-first jumbo-capsule design, with supersonic retropropulsion with canted engines added to reduce heatshield thermal loading. The switch mas made to the sidefirst entry to further reduce heatshield loading whilst eliminating the need for retropropulsion (and the propellant needed for it) during entry. SpaceX are also not using Hydrogen, so an actively cooled heatshield is not a viable option - it would need a separate coolant fluid to be recirculated, or an extreme Methane flow volume to keep temperatures low enough to avoid coking (well below the temperatures the heatshield would actually need to be cooled to for structural reasons).Difficult to imagine how the mass of the strengthening they need to add to the second stage could be higher than the mass of the entire first stage, which is almost what you'd be adding if you go single-stage.This might be Zack's best deep dive yet.
Wow, what a great video. A few things come to mind:
Starship is paying a large mass penalty for staging, being long and skinny, reentering sideways, the mode switch at landing, and needing to cover the base of the first stage in engines. To the point where I'd be surprised if a Bono-style single stage vehicle built around a Raptor that meets specs wouldn't actually have a lower payload fraction than the two-stage Starship. You're paying such a high price for the shape and concept of operation, maybe those propellant consumption efficiency arguments aren't so strong.
However, man oh man is stainless steel an advantage in terms of debugging. And wow, what a team!
Imagine how awful Skylon's structural problems would be!
And appreciate how good Stoke's configuration is!
I think all we are seeing is the SpaceX iterative design & development process at work. They start by making it as light as possible, then test it, and add strength as required to address issues found during testing.
When they initially add that strengthening to existing vehicles it is quick and dirty, but it also goes back to the design team and they end up with a much more elegant implementation, probably with a lower mass penalty, several vehicle iterations down the line.
Yeah, that may have been a little enthusiastic. However, the video was very good and I recommend it to people. It was, as you say, fantastic to see the iterative process in action.
It did make clear that Starship is paying a heavy price, in mass and time, for problems that it didn’t really have to solve unless there is some secret compelling reason for the high-lift high-crossrange reentry style. It would not surprise me to find they are doubling the mass of the second stage relative to what a Stoke-like configuration would require, assuming you did a Stoke-like configuration with methane and not hydrogen. That isn’t the mass of the first stage, but that’s not really how the math works anyway.
This belongs in another thread so I'll leave it at this comment, but it occurred to me on watching that video that Stoke is introducing a problem that will need to be solved by adding mass in interfacing a long and skinny first stage to the middle of the heat shield on the second stage. Maybe they’d be better off with the first stage shaped roughly like the second stage, or at least fatter, such that it could transfer its loads where the second stage engines are and there are already hard points.
Heck, they could go all in, and buy the launch vehicle and satellites from those folks - it would be much quicker and cheaper. But that logic ends with them just buying Starlink bandwidth, which would probably by far the cheapest option even if Vulcan didn’t fail.<snip>There is always the last option with the folks from Hawthorne.
For Amazon, if Vulcan fails, they're realistically out of options for Kuiper. Buying ULA won't change that.
Not on https://www.fly.faa.gov/adv/adv_spt.jsp 27th March
Does this suggest a slip or is it not a concern for some reason?
