SpaceX (Vol. 2)

[annodomini2]

Talksteer said:

annodomini2 said:

RizzoTheRat said:

loudlashadjuster said:

Too massive, maybe. A small misalignment, an unintended torque. Bang.

Having said that, it’s not hugely heavier than the SSO.

Also, where would you put the hatch and docking mechanism?

They've done a few mockup/renders of Starship docked to the ISS, some with a node mounted hatch, presumably similar to Dragon, and some with it on the side more like the shuttle. Maximum landing weight is of the shuttle is about 100 tonnes, which I think Isn't that dissimilar to Starship, that's potentially a lot of load on the docking port if anything goes wrong. How flexible are they?

Current prototypes are about 120-130 tonnes dry, without payload.

On orbit Starship for going to ISS will have all the habitation gear for a manned flight + any other payload 50-150 tonnes

Plus de-orbit and landing fuel 50-100 tonnes

We can do a few calcs:

Max inert weight of the Starship could be 130 tones dry plus 150 tonnes payload. Though I'm sure that the 150 is probably achieved when the vessel is less than 130 tonnes dry!

We can put a ceiling on the landing fuel as it is 2 raptors for 17 seconds which is about 20 tonnes of fuel, in practice this is probably an accurate amount including margins as the Raptors will be throttled for most of that time.

Fuel estimate agreed based on current data, but that's for the empty prototype at a draggy terminal velocity, not coming from orbit.

For example most capsules without parachutes would hit their landing zone iro 250mph, roughly double what could be achieved so far with current testing.

As KE goes up with the square of speed + you have additional mass, you need roughly 4-5x the fuel, but that depends on how effective the belly flop is from orbit. So could be less.

Talksteer said:

Assuming that the Starship has the same delta v under OMS as the Shuttle (300ms-1) that would mean that it need 8% of its mass as fuel. This brings us to a max on orbit mass of 320 tonnes.

Probably less, The Shuttle had a fairly steep entry profile, but Starship will have higher fuel load on orbit.

Talksteer said:

However we could do an estimate for a more reasonable version of Starship to visit the ISS. The ISS can't accommodate hundreds to people and I doubt we are ready to risk people on rockets by the hundred either. So lets have a max crew of 20.

Current capsules mass in the range of 5-10 tonnes with all systems.

If we allow 10kg/m2 to insulate and seal the craft that adds 5000kg
If we allow 15kg per person for life support systems (see space suit) and we have a crew of 20 - 300kg
A large civil aircraft normally has about 20kg per passenger of fitting and fixtures (HVAC etc) - 400kg
1kg per person day of consumables - 200kg
Provision 250kg per person for an ejector seat (I don't like the landing), space suits, displays, life support connections- 5000kg
A caravans worth of beds, tables, decks and stters -2000kg
Solar panels, power conversion equipment and decent battery -1000kg
Crew 20 x 100kg - 2000kg

Total 15,900kg

Which is a long winded way of saying I don't think any reasonable timeframe crew vessel is going to be using a fraction of the payload volume.

If we round up the delivery to 20 tonnes to include cargo provisions for ISS that gets us to:

I'd go with that.

Talksteer said:

120,000 inert mass
20,000 cargo and crew fittings
20,000 landing fuel
13,000 OMS fuel (partially burnt by the time you get there)

173 tonnes, so not massively different to the STS

120 Dry mass without payload
20 Payload
100 Landing propellant
20 De-orbit propellant
30 Dead tank (propellant that's in the tanks but can't be used + reserve for landing)

290 ish, it's all speculation for now, but it's going to be a lot heavier than the shuttle on orbit.

Edited by annodomini2 on Wednesday 13th April 10:08

[Ayahuasca]

Just watched the Netflix thing on Space X.

Good quote from Elon - if you can have one superpower, the one you want is luck.

[fuzzyyo]

knitware said:

Anyone watched 'Return to Space' Netflix. I really enjoyed this documentary film logging the efforts of Elon and his SpaceX team, the man is quite remarkable.

The man is a but sometimes it takes a to drive things forward.

[Beati Dogu]

The next Falcon 9 flight is today, 15th April from Vandenberg, California.

Launch time is 2.41 pm UK time (1:41 pm UTC / 6.41 am local).

This is the NROL-85 national security mission and the booster is B1071-2. It's the first time a reused booster has been used for the National Reconnaissance Office. The booster also launched the NROL-87 mission back in February.

The plan is to land back at the launch site. It should be a daylight launch and hopefully it's not foggy.

[Flooble]

I thought it was tomorrow?

[Smiljan]

Flooble said:

I thought it was tomorrow?

It is tomorrow 16th

https://www.spacex.com/launches/nrol-85/

[Beati Dogu]

They moved it to Saturday at short notice - "the additional time allows teams to complete pre-launch checkouts and data reviews."

Lots of people drove up there for nothing.

UPDATE: Now Sunday.

Edited by Beati Dogu on Saturday 16th April 01:04

[Beati Dogu]

It launched & landed through the gloom OK. Their 14th launch of the year already.

There's another Starlink launch due on Thursday and the Crew 4 mission to the ISS on Saturday.

[Hill92]

Tim Dodd (EverydayAstronaut) has been spending more time with Elon MuskT Starbase.

https://twitter.com/Erdayastronaut/status/15155212...

Hopefully another set of interview videos arriving soon.

[Beati Dogu]

It’ll probably be next month some time.

[Petrus1983]

Hill92 said:

Tim Dodd (EverydayAstronaut) has been spending more time with Elon MuskT Starbase.

https://twitter.com/Erdayastronaut/status/15155212...

Hopefully another set of interview videos arriving soon.

I wonder if Elon crashes at Tim’s place in exchange.

[Beati Dogu]

Tim was at the Tesla gigafactory opening in Austin, Texas the other day. I guess it made sense to go over to Boca Chica while he was in the area.

[MartG]

Falcon 9 Starlink launch due at 16:14 BST today https://www.youtube.com/watch?v=s6yBwQSrtFY

[Beati Dogu]

That'll be Booster B1060's 12th flight.

[MartG]

Now showing as 18:45

[Stan the Bat]

MartG said:

Now showing as 18:45

Thanks for that, just caught it in time.

[Beati Dogu]

Yesterday's Starlink flight passes the Crew-4 stack in the foreground:




The Axiom-1 crew are still on the ISS though. It was supposed to be a 12 day flight, but it's two days past that already. Their departure has been delayed due to bad weather in the splashdown areas off Florida. I don't suppose they'll mind somehow.

The NASA Crew 4 launch has been put back as a consequence. It will be on Tuesday 26th at the earliest now.

[Beati Dogu]

The Axiom-1 crew are now expected to depart the ISS tonight at just before 2am UK time (00.55 UTC).

Splashdown is at ~6pm Monday UK time (17.00 UTC). The primary splashdown area is in the Atlantic (off Florida).

SpaceX undocking stream - https://www.youtube.com/watch?v=GBFZghqrI_4

[Beati Dogu]

Starship Booster 7's downcomer pipe not looking so good:



It's supposed to be tubular, but has been crimped by fuel pressure, or the lack of it. It links the top tank, through the lower tank to the engine manifold.

Booster 7 was the one expected to actually fly, but that looks unlikely now. Booster 8 is being stacked currently.

[annodomini2]

Beati Dogu said:

Starship Booster 7's downcomer pipe not looking so good:



It's supposed to be tubular, but has been crimped by fuel pressure, or the lack of it. It links the top tank, through the lower tank to the engine manifold.

Booster 7 was the one expected to actually fly, but that looks unlikely now. Booster 8 is being stacked currently.

They look to be trying to fix it.