RCgothic

Flap testing in progress. Some non-definitive venting by the ditch near the tank farm. If we're still aiming for 9.54am (1594 UTC) we need to see some proper tank farm activity soon.

It's definitely going down today. Just watched the flight termination system get armed on NSF. Pad is cleared. Currently looks like we're go for Launch in 40 mins or so. RCS testing in progress.

I agree, although not all capabilities get screwed by mission changes. It would have been possible to go with a more flexible architecture better able to cope with mission changes. I think it would be hard to go wrong by optimising 2-stage to LEO with an optional 3rd stage for earth departure, for instance. But then politically if a rocket is capable of a changing mission, perhaps that would have put the lunar program at risk of cancellation yet again (although in that case at least the rocket would survive the death of the program for to its universal usefulness). I'm a little bit split on whether large rockets should yet be the domain of fixed price contacts, but certainly this plus cost contact doesn't seem to have worked very well.

The pointier nose is interesting, I had thought Elon had said it would get blunter. Maybe beginner-level Japanese is enough to get me on DearMoon?

I would love a seat, and I'd fly in 2023 given a chance. Such an incredible experience is surely worth a chance of it being ultimate. But I'm not a creative type, and not really in a position to be meaningfully supportive of the other passengers, so I'm not eligible alas.

6 of the 9 engines have their TEA/TEB igniters plumbed to the pad, they can't be air-started. The other 3 engines share an onboard reservoir. I think the centre engine must ignite for a safe landing. CofG is too low to safely land on one of the outer engines with gimbal. There *may* be some redundancy in the other 2 if there's enough propellant margin (bearing in mind a failure reduces the nominal margin) and the failure is identified really enough to swap to plan B.

The last time they had an engine out on ascent it caused them to overshoot the droneship. Less thrust means longer to orbit means further downrange. I'm surprised they could still attempt a landing at all, the engine out must have been very late in the first stage burn.

Maybe with a stubbier aspect ratio they aren't needed?

Crew-rated as well. I'm really looking forward to seeing Neutron fly! That looks like 7 engines in the first stage, so they're going to need a bigger first stage engines than Rutherford. Well it also be electric cycle, or a more traditional kerolox gas generator?

They think that a year may not be a hard limit. They'll find a way to recertify them for flight.

Slipping towards March 2022 then.

1. They have enough comms to justify having a director, communications? 2. Ah, cool, a 1st stage mockup in 3 pieces. 3. 23ft is smaller than Starship, which is technically flying. 4. Cool fairing, though I think we've seen one before. Pretty sure Atlas V has a fairing that's more than half that volume, as is FH's new fairing (It'll fly first). Less than half a Starship. 5. The TATC building is a very tall empty building. 6. The rocket garage is a very long empty building. 7. Ok, the road to space is pretty cool. 8. Human spaceflight from LC36, yes please. What capsule? 9. They really do seem to have all the facilities ready, just no rocket. Agreed Q422 means 23. 10. More of these videos please.

Economically it might not make much difference whether $ are spent on coffee, SLS, or Falcon Heavies, economic stimulus being economic stimulus, but if what you're interested in is Spaceflight Milestones Achieved then there'll be a vast difference in outcomes depending on which you spend money on.

The 38t to TLI that B1B can do is more than enough to get Orion into LLO with a stretched service module. They should have just come straight to this as the baseline version. Then send the lander on a second launch. 38t doesn't get you 4 people for an extended stay, but it might get you 2 for an extended stay. 38t to TLI is roughly 28t in LLO, nearly twice Apollo. But there's no plan to upgrade the ESM, and they couldn't build SLSs fast enough to support this anyway. "But even a long stay isn't a sustainable presence, that's why we need gateway!" they counter-argue despite gateway going to be mostly vacant and not actually anywhere interesting in itself. That's just a half-measures. Go the whole way and make a permanently inhabited surface base. Cheap frequent cargo is what enables sustainable presences. Does SLS do that? No.

Working an Apollo lander through my spreadsheet (~15t) comes up with about 64t to TLI with Orion, so yeah I agree with your figure. That'd be 155t to LEO with SLS, which isn't on their upgrade path at all. Ironically, uprated Saturn V with F1As could probably have done it, but TBH safety is one of the few things you can't really fault SLS Orion on. Saturn V was probably lucky not to lose a crew, nevermind the crew they almost lost on Apollo.

The difference between what 2 people need for a brief excursion and what 4 people need for an extended stay plus a tonne of cargo retun gets quite large, aye.

Sure, but there were other options between "do it Apollo style" and "do it SLS style", even without considering the launchers that have come along in the mean time. Capsule and lander LLO rendezvous with a cadence of 4 missions/8 launches per year should have been possible if SLS and Orion had actually be designed coherently. If SLS and the ESM were a little bigger (B1B as a base) and/or Orion was a little lighter. EOR was and remains viable, with/without Lunar rendezvous as well. Delta IV Heavy and Atlas V both could have been crew rated with a will. Then the Falcon family came along. You just look at the program and go "yes, we're going back and that's cool, but we could be doing this so much better." And despite NASAcs continuous use of the political Nov 2021 date for Artemis 1, multiple sources now hearing the realistic internal target is NET Feb 2022: Sure I've seen at least one other as well, but struggling to dig it up right now.

Ouch, basically. Let's assume a lunar module. Apollo Ascent was roughly 2.4t dry for 2 people, so let's assume double that for 4, plus 100% again for an extended stay and a bit more comfort. Roughly 7t. Plus return with 1t of samples. To get back to LLO (1730m/s) takes 7 more tons of propellant at 310 ISP to give a bit of margin for rendezvous (1910m/s) so the ascent stage will weigh 14t landed, 15t on launch, and 8t back in LLO. To land the ascent stage (14t) from LLO plus 1t of cargo might be 21t landed, assuming 6t for the stage dry (again, a little under 3x Apollo). To get there from LLO (1730m/s) including a decent landing margin (2110m/s) is 21t of propellant at 310 ISP, so 42t total for the lunar lander system. Then we need to know how much is needed to return to earth. Orion weighs 10.4t and the ESM weighs about 4.9t dry for its original 8.6t of propellant. It'll need a bit more propellant to shift Orion and 42t of LM into LLO, so it'll need to be stretched a bit. It'll work out at about 7t dry with larger tanks (see later). Plus we've taken 1t of samples from the surface, so that's 10.4+7+1= 18.4t dry. To send that back to earth (820m/s)with some margin (880m/s) requires 6t of residual propellant in the tanks at 319s ISP. So! Now we know how much has to be braked into LLO by the ESM. 42t of lander (inc 1t landed cargo). 10.4t Orion. 7t ESM. And 6t propellant to get home. 65.4t "dry", although in this case dry just means mass at end of burn because there'll be residual propellant in the ESM. To drop that into LLO from TLI (820m/s) would take 24t of propellant, plus some margin for rendezvous/ orbital manoeuvres/station keeping/ (980m/s). So we need to send 65.4t payload plus 24t fuel is 89.4t to the moon from LEO not counting Earth Departure Stage. (Note that the total fuel for the ESM is therefore 30t, or 21.4t extra. At 10% tank fraction for hypergolic tanks that's an extra 2.1t on the original 4.9 gives the new dry weight of 7t I've been using.) To send 90t near enough to TLI from LEO (plus ~5t of payload attach fittings) takes 115t of hydrogen and 12t of earth departure stage. SLS would therefore have had to be designed to put around 220t into LEO. That's more than twice its block 1 configuration and even 90,t more than Block 2. But is there a rocket in development that can do it? At 370s ISP, a Starship Derived Stage would need to put roughly 380t into LEO to send 95t of payload/PAF and 61t of stripped down Starship to TLI. 225t propellant required. That sounds implausible, but I'll run some numbers anyway. Starship can put ~100t of payload into LEO in its reusable configuration. That's not counting ~30t of landing fuel, or the ~80t dry mass, 210t all inc. Extraneous weight like flaps, fairing and heat shield can be deleted. Include the landing fuel for departure instead and take more fuel instead of the unnecessary bits and an expendable version could be 61t for the stage (5% of 1220t propellant -assuming Stainless isn't quite as good as F9US's 3.5% despite Starship's square/cube advantage) and 95t for payload and PAF, leaving 54t of fuel (210t total in LEO). That's still 174t short of TLI. So we look at Superheavy. How much margin is wasted on an RTLS landing Vs expendable? It's hard to be sure. It's thought that F9 takes a roughly 40% payload penalty when going RTLS, so let's go with that. If 210t to LEO is 60% of Superheavy's expendable capability, it might be able to manage ~350t to LEO fully expendable. So no. Not even fully expendable Starship/Superheavy could do that in a single launch. However! That assumes the starship derived rocket is lugging an entire starship to TLI, which is carrying oversized tanks for 1200t of propellant because it's also doing the job of an upper stage. That isn't a disadvantage I put on the hydrogen powered equivalent, so let's look at a raptor derived 3rd stage, which would be much lighter! With 150t of propellant, a Raptor 3rd stage could weigh 7.5t. Plus 94.5t of payload is 250t to LEO. That should be well within the capabilities of an expendable Starship/Superheavy!

At least it wasn't one of the flight leaders.

They'll need to actually put a pathfinder on the launch facilities to make sure everything fits. I'd be amazed if the first vehicle out of the factory is a flight article.

Yup.

Found it:

Probably just a pathfinder.

Btw, I'd expect a fully expendable starship to have a substantially lighter dry weight. No fins, no heatshield, no header tanks and disposable fairing. At 5% dry mass, disposable starship would be ~62.5t. F9US is 3.9%. Expendable Starship could even be better because of the way square cube works. Expendable Starship may be a fairly niche application for distant destinations once they get orbital refuelling worked out. They absolutely do not want to be expending these things. But it kind of makes sense as an easily acheivable early milestone. Personally if I were Elon I'd like to do it just to smash the "double Saturn V to LEO" marker.