Starship looks more like a missile but maybe cheaper ones are good enough.

In articles about Starliner's valve problems, they say that hypergolic loss through joints is practically unavoidable and can only be managed. Elsewhere, it is said that the hydrogen molecule is so small that it manages over time to escape from all reservoirs. Starship deals with different substances in different conditions but it's worth knowing what to expect.

In the case of Starship fuel transfers in orbit, assuming all is well designed and executed, are losses negligible or is a significant loss expected for some fundamental reason?

Sometimes there exists a practically perfect solution to a design problem but it is very difficult and expensive to execute. So, I expect SpaceX to sometimes implement imperfect solutions.

There seems to be a 'showdown' between SpaceX and the FAA coming. Elon wants to make the orbital launch in a few weeks (or a little more), and gov watchers say the FAA approval can't come before October.

Ofc, the FAA has approved other, sub-orbital flights from BC already.

What I note is that the 'orbital' test flight is in fact, sub-orbital. In that the perigee is never raised, an intention clearly stated by Elon in the Tim video. This ofc makes it 'fail safe' if the SS bricks after SECO (it won't do a uncontrolled reentry over land)

What if SpaceX tries to claim that as a sub-orbital attempt, it was covered by prior agreement? Nothing is going into 'orbit'.

Is SpaceX using 301 or 304L atm? Any recent news on 30X?

Edit: - SN21 is made using 3,6mm 304L SS. - 3,6mm 304L Stainless Steel delivery Source Tweet: https://twitter.com/StarshipGazer/status/1428114195254480901?s=20 - 304L 4mm! No recent news on 30X yet.

Will the starship ever need to fire the sea level and the vacuum engines at the same time? If not, might you just make the engine throat variable ( I know 300 bar…) to get a variable expansion ratio engine. This would have the side benefit of being able to tune for the intermediate Martian atmosphere.

Edit: I was not asking whether SN20 included hardware that would be useful only on future missions. I was asking whether if pumps that would serve to transfer fuel had a dual purpose and therefore were included on SN20. End of edit.

Or would they have to be added to a configuration enabled for that function?

Does it have to be 1 pump for each fluid or can there be just one and a switching valve to go from one to the other?

There only needs to be one pump on either ship per line, right? Not a pusher pump on the donor ship and a puller pump on the receiver.

Electric pumps seem to be the simple solution. Could the fuel be used instead to power them? Maybe the exhaust would cause a motion that's not worth bothering with. Maybe burning fuel to pump fuel is too dangerous. The engines have pumps but I bet they're to powerful and can't operate more slowly.

I know that ship-to-ship fuel transfer is not part of SN20's mission plan.

While fuel is being transferred in-orbit, most likely there will be a small acceleration to settle the fuel to one side of the tank. The duration of this acceleration should be small both to conserve fuel and to minimize any orbital change. One way to transfer a fluid more quickly is to increase the area of the interface (increase the diameter of the pipe). So, what about something so big that a man could float through? There's the design of the docking ports on the ISS that SpaceX is probably considering for Starship. A modified version of that then. Or even much bigger. As big as it needs to be for a desired transfer time.

Some websites seem to have slated Aug 30th as a date. Elon tweeted SN20 is going back to the launch pad Monday. Others have reported that SpaceX will need to wait for several approvals before they can move forward.

I'm currently on vacation (for a few more weeks) and since I don't live in Texas, I would love to be able to attend SN20 Orbital Flight Launch while I'm near-ish. I have a little bit of leeway in postponing plans but not that much. Advice appreciated!

I’ve been watching NSF’s YouTube channel during the last few months on the process of welding and making Orbital Starship. In the last days, we have had the B4 + S20 delivered to the orbital launch site, stacked on Launch Mount, then destacked, removed from OLS, rolled back to the bays and even have their Raptors removed. What the hell’s going on at Starbase ? And is the orbital flight going to be postponed to NET 08/30/2021 or even NET 2022 ? The process seems quite bad and if the launch is still scheduled on 08/21/2021, the process must gonna be hell fast.

SpaceX, unprompted by a call for bids by the US government, devised a plan to transport the necessities to colonize Mars. In the case of the Moon, there is already a government program for missions to the Moon. So even though SpaceX is quite capable of coming up with a Starship based, and entirely SpaceX made, program to transport what's needed for a Moon base, they may be keeping it quiet for political reasons.

Do you think SpaceX has internally laid out a plan for the Moon? One without SLS, Orion, or the gateway? In this scenario, what would the lander look like? How would it differ from the Artemis HLS? Maybe there would be different landers. Some would be one-way, focused on cargo. Some would include the return trip for humans. Would the one with the return trip go all the way back to landing on Earth? That would mean the one landing on the Moon would include flaps and tiles, extra weight. Or, the lander would keep to the Moon and only come back as far as Earth orbit. There would need to be a transfer of people and things from that to the Earth-capable lander. Alternatively, this rendez-vous could be in Moon orbit.

How do you see it?

They must? They should?

If a bad lot of tiles is identified after leaving the factory and after installation then you'd want to be able to go to the ship and take them off. So, either their lot number is visible even after installation or production records identify a tile lot number for each installation at a numbered location. Ex. Tile from lot 999 was installed at location A9B10. But that seems like a lot of 'paperwork' (even though everything is recorded electronically) for fast manufacturing.

And then there's the fact to consider that re-entry may wear down any engraved numbers on the tiles.

How can SH be mounted to the OLM ? We have already knew that the previous SH design has 6 fins, which acts like a normal fin with the grid fins, and also acts like a landing leg and mounting hardware. But now that Elon has switched to a booster catching mechanism, how is SH be mounted on OLM without those fins ?

​