sevenperforce

Would they forego the static fire? Or would they do the static fire with the payload integrated? If 24 hours is measured from T-0 to T-0, then we have the following sequence: Launch to landing: <1 hr Landing to safing and acquisition: 1 hr Return to strongback: 3 hrs Return to pad; prop load: 3 hrs Static fire and post-fire review: 1 hr Return to hanger: 1 hrs Payload integration: 4 hrs Return to pad, prop load: 3 hrs Just about 7 hours of buffer in there.

Uptick in isp is expected simply due to pressure thrust. Higher propellant flow means higher chamber pressure, which means bigger pressure drop at SL. Engines will be underexpanded even at liftoff. Another second or two of isp could be gained by adding slightly larger engine bells, but I doubt they have space for that (and it would throw a massive wrench into production). By my numbers, the Merlin 1D now has a SL TWR of 183 and a vacuum TWR of 198. If they can push it up to 10% more than before, they can hit a TWR of 201.9:1. Au contraire. The bigger grid fins allow AoA that approaches a 1:1 body-lift glide ratio, so that they essentially only have to boostback halfway and can "fly" the remaining distance. That's for RTLS. For ASDS landings with boostback, the same thing is true; better glide ratio means a smaller boostback trajectory adjustment to hit the droneship. Larger grid fins can also handle more re-entry heat, which means potentially shorter entry burns. They can decrease the total landing dV. Suppose terminal velocity for the Al-fin stage is 290 m/s and terminal velocity for the Ti-fin stage is 260 m/s. Not only is that a savings of 30 m/s on the landing burn, but that means a lighter stage, so a better glide ratio and lower entry heating and a smaller boostback burn and exponentially more propellant deliverable to the second stage at staging.

All four titanium grid fins together are probably less than a 100 kg increase over the Al ones. And the larger grid fins' ability to increase drag on landing and increase lift coefficient means they need less propellant, so they can burn more prop on ascent, which means m0/m1 increases rather than decreases.

Oh, obviously. I certainly don't suggest doubling the dry mass of the first stage. I'm saying that increases in the mass of recovery components has no significant impact to liftoff TWR.

They are about 40% heavier but that is a tiny blip compared to the dry mass of S1, let alone the wet mass. You could literally double the dry mass of the first stage and it would only reduce liftoff TWR by about 3.8%. Plus, they've already been flying titanium grid fins on Block 3 and Block 4. The bigger grid fins actually pay for themselves in terms of weight reduction because they allow the stage to glide back with higher AoA, saving fuel.

I doubt there was any appreciable increase in dry mass. Maybe 0.5-1% at most. The new legs are lighter, not heavier, and the octaweb is the same weight (it's simply bolted rather than welded now). No TPS on S2 yet. The new grid fins are probably not much heavier than the old ones; titanium is stronger than aluminum.

Obligatory: In USSR, gyroscope install you. So this is major. I was expecting a 2-4% increase in S1 thrust; 5% at most. Bumping up thrust by a whopping 8% directly cuts gravity drag by 7.5%. On a nominal GTO launch, that means up to 109 m/s more can be added to the second stage at staging, simply by virtue of higher liftoff thrust. If S2 starts with 109 m/s more, it can push a 6% larger payload to GTO, or it can push the same payload to a 22% higher (!!!!) apogee. Incidentally, this will make RTLS more challenging because the first stage will be further downrange and moving faster. @tater Perhaps that's why RTLS actually is always harder on the booster: in order to reverse direction, the S1 has to do a three-engine full-throttle boostback as soon as possible, which probably means extremely high gees and corresponding stresses. Boostback on ASDS landings, when they happen, are more like trajectory corrections than anything else and can probably be done at slightly lower throttle. Of course they are also much shorter in duration. Not too long ago, even Elon was saying they merely wanted to recover the second stage for testing. Now he is back to full reuse. That would be epic for sure. Neat that Iridium is letting them use the constellation as a relay during entry; I assume this means current vehicles have additional instrumentation added to S2. Wonder if the TPS will be external (visible on launch) or inside the fairing/interstage. I'm guessing they will not attempt S2 recovery on Dragon flights, in order to keep the man-rated vehicle design frozen. If not, then it will definitely need to be internal. "Big milestone" is putting it lightly. "Nah, we only need to build a few dozen rockets to fulfill a bigger launch manifest than all other worldwide launches combined. No biggie." ....whoa. That's huge. Huger than huge. Yeah, the subchilled performance boost and greater propellant load isn't required for ISS flights. But I still say loading astronauts first is, technically, safer. Though NASA's not exactly going to listen to me. I do believe the hype on COPV 2 being "most advanced". This is their pain point. Composites can't really be molded or changed after it's created, though. The biggest problem is that composites are technically flammable. Which is not a nice thing to have in a tank full of LOX.

Which you can afford to do if you have money to burn.

Zero chance.

That failure will go down (see what I did there?) in history. The best part is, you can see what is wrong when you watch the launch.

It happens. But not often.

With all of Elon's talk about AI, you'd think they'd have a fast AI to provide concrete go-no-go for a team review following abort. Not ULA.

SpaceX may be ridiculously cheaper than everybody else on the market, but the delays and scrubs and dependencies...it makes them look bad.

Vapor from interstage is normal.

How long is the window?

Oh, and if we assume, reasonably, that the $1M/launch in recovery cost is more than enough to allow for more refurbishment every 10 flights, and accept Elon's claim of 100 reuses per booster, and assume they get fairing reuse sorted with an average of 20 uses per fairing, then the nominal amortized cost per flight becomes $19.7M. Elon described the payload fairing as a "pallet of $6M cash falling out of the sky" so it sounds like that's their nominal in-house cost.

I bet the "how you count it" is whether you include the static fire propellant in the total or not. Musk has said the payload fairing costs around $6M. So we finally have (rough) numbers: Payload fairing: $6M Fuel and consumables: $0.5M Launch costs, not including fuel: $5.5M Second stage: $12M Booster: $36M Total in-house cost of expendable launch: $60M If SX sells an expendable Falcon 9 launch for approximately $95M, that means they're looking at a 37% profit margin. If we guesstimate Block 5 recovery costs at $1M per flight and assume only 10 flights per booster, then nominal in-house cost per flight is $28.6M. If they continue selling recoverable launches at $62M each, that's a 53.9% profit margin. They are about to make so much bloody money..........

Bezos says each NG first stage should be capable of 100 reuses, but makes no claims as to refurbishment timeframe or sequence. My god that will be glorious.

Except for the whole working part.

They have modified Merlins so the Block 5 update can sustain 8% increase in thrust over Block 4, but they will run this Block 5 MVac at Block 4 thrust levels because they don't need the extra performance on today's mission.

Half of the fun, for me, is trying to match real-world rockets with stock parts (+/- Tweakscale) and subassemblies. Finding out what works, what doesn't, etc. is more fun than just dropping in prefab stages. Plus, this way I have more margin to play with. And I don't have RSS/RO on my game.

My own newly-updated Block 5 Falcon (WITH BONUS TEL) is also ready on the pad:

So...mature. ...Which is a metal bottle wrapped with several layers of carbon fiber or another composite, which is then filled with a pressurized gas. In SpaceX's case, this is helium, which is released into the fuel tanks as fuel is burned to take up the space to prevent the rocket from collapsing in on itself due to external pressure. The Falcon doesn't have balloon tanks, though, the above example does, which means the pressurization is giving the rocket its strength. This would not happen to Falcon on the pad, but it might in flight. Also, if you don't have head pressure in the tanks, the inlet pressure at the turbopump can get really, really low. Though this is not so much of a problem on ascent because you have gravity and acceleration helping out.

Size is a big deal. High-diameter, low-wall-thickness tubes like a Falcon 9 (or even a Falcon 1) have a really poor bending moment, especially when they are constructed from metal. The STS SRBs could survive hitting the water because they were hella strong in the first place, being the combustion chamber and all. A composite rocket stage smaller than a Falcon 1, with very dense propellants allowing small tank size, would have a pretty decent shot of surviving chuted splashdown. Especially packing a sturdy aerospike rather than a flimsy de Laval.

We know it has redesigned COPVs, and more of them. Thrust is probably uprated on the MVac. I wouldn't be surprised if configurations were adjusted to allow a little space for throwing TPS or a ballute on there.