RCgothic

Cybertruck is definitely an acquired taste. I doubt it will even be road legal in Europe.

I retract some previous statements. My maths was wrong. >.< But the FUS's mass fraction *is* incredible.

Edit: retracted due to maths error. *Embarrassed*

That does look better! Less like a garden gas tank.

Sure is busy at the Cape! At first I thought this was a retest of yesterday, but no, different mission.

Not needed for the current plan, anyway. Just a fantasy plan in which Orion SLS isn't required.

A fair point, but I don't think adding a crew access tower to SLC-40 would be that big a deal.

Yes, but not thanks to Centaur or DCSS being better than FUS. Centaur and DCSS light higher and faster than F9US so they don't have to do as much work. That's thanks to DIVH and AtlasV. F9US has at least 4.4km/s more DV than DCSS and Centaur for any mass of payload between 0t and 16t. F9US does more work than the second stage of any other operational rocket. SpaceX don't have any reason to do hydrolox. Would their first stage be improved by hydrolox? No. It couldn't get off the pad without boosters. Would the second stage be improved? No. The extra insulation would reduce the mass fraction more than the ISP gains.

I would have thought it must have improved on last time, as it failed in a different place? But yup, no confirmation there yet either.

SpaceX haven't tweeted out confirmation of a successful static fire, which is worrying for today's mission. It's usually done quite quickly after the test.

RS25 only makes sense as a recoverable reused engine. That's the only possible justification for an engine with a marginal cost of $100m. Amortise the cost with multiple reuses. But it's also pretty hard to recover a sustainer engine. To be completely fair to the HLSs, Orion passed CDR 1.5 years ago and will fly with crew in 1.5ish years, and the hold up in its first flight isn't Orion but SLS. Plus it's, you know, Boeing. So that 3 years can probably be shortened with an aggressive schedule. But yes, it's a big ask to get from development contracts to flight in 5 years. The only actual hardware we can see is Starship. At a push second stage reuse doesn't absolutely need to work out before the lunar lander mission. It'd probably still be more economical and schedule friendly not expend a load of tankers than launch a lander on SLS. But in-flight refuelling absolutely has to work.

I love how the high bay is suddenly being called the mid bay because there's a higher bay under construction!

Falcon's upper stage isn't a weakness. FUS is an incredible stage. It develops more DV than even Centaur for any mass of payload. It's arguably the best upper stage ever developed bar none due to its amazing mass fraction. If Falcon 9 has a weakness it's that the first stage stages low and slow which means the second stage is starting from a handicapped position. FUS really needs a larger 1st stage. But it's staging low and slow that enables its killer capability of reuse, so it's not easy to fix without losing that. The partially expendable and expendable FH modes do largely fix that, you're right, at the cost of losing the core stage.

Too little over 15y too late. The competitor isn't F9. The target is Starship.

Falcon 9 and Falcon Heavy could send Dragon2 to *LLO* and return without crew-rating FH. SLS does not have the capability to do the same with Orion. Four flights of proven boosters that have flown is not necessarily more risky than 3 flights including a booster that hasn't and continues to be plagued by delays. And risk isn't just about safety or mission success rate, it's also about schedule. Will SLS Orion be ready to deliver astronauts to a moon landing in 2024? Probably not. Could F9/FH be ready to deliver astronauts to a moon landing in 2024? I think they have a higher state of current readiness and an agility and development pace that place them well to deliver.

*Gestures at current Artemis plans.*

Sending the lander piecewise via FH, NG or Vulcan is literally 2 of the 3 options Artemis is pursuing. Falcon Heavy can probably push 30te to TLI with EOR which translates to a 22te lander by the time you get to LLO. In two launches. 4 launches all up. And if you feel like it, send the ascent and descent stages separately. Now you've got a 44te lander to LLO. In 6 launches all up. At less booster cost than the *engines* of a single SLS. 82te total to TLI. Twice Saturn V. Just 5 cores expended.

Falcon Heavy isn't crew rated, which means Moon!Dragon is going up on Falcon9, limiting it to 15.8te max (reusable, although 15.8te is the heaviest monolithic payload we've ever seen F9 launch). The article suggested four SpaceX launches total, so let's see if we can make that work. Falcon Heavy semi-expendable can put 90% of 63.8te in LEO. That's 57.4te (of which 4.5t is F9US, conservatively counted as payload to LEO). Plus 15.8te Moon!Dragon is 73.2te. To push that through TLI takes about 50t of propellant which leaves 7.5te payload on the FH launch. (27.5te to TLI) The Falcon Heavy launch payload is a drop tank with an APAS adaptor to mate to Moon!Dragon. 6.5te propellant with 0.3te APAS and 90% propellant fraction. 23.3wet, 16.8drop tank exhaustion, 960m/s enough for LOI and lunar manoeuvres. Meanwhile Moon!Dragon's drop in service module needs 3t of propellant in addition to Dragon's onboard supply. That leaves 3t for crew, extended life support, comms, and rear APAS. 15.8te wet, 11.5te dry, 935m/s. This could be limited by how much load a F9US can support, which is unknown.

With a large proportion of its payload given over to extended hypergolic tanks in the trunk Dragon can push over 1200m/s with its Draco thrusters.

So Starship/Superheavy can launch 150t to LEO with RTLS. What could it do landing downrange on one of the super-platforms being considered? Over 200t?

Pretty sure Mars return requires aerobraking as there isn't enough DV to do SSFMTLEO. That requires functioning aero surfaces, so you don't eliminate the main point of failure of a crewed landing that way.

Superheavy pad is under construction. I think they may be doing a raised pad because the ground is too soft for an underground flame diverter.

Hah

What I take from this is Virgin to get Spaceship used as a suborbital astronaut trainer for other orbital astronaut launch services.

True. There was an assertion up-thread that Starship could fly often enough to demonstrate its reliability empirically. But more than 270 flights would be required in that instance. The number of flights required to demonstrate the reliability would almost certainly get into "expected failures" territory, in which case you need even more flights or even better reliability. To fly 1500 flights and expect to complete that test program with only 0.1 expected failure, you need LOV to be better than 1 in 15000 flights. Getting into early airliner territory there!