RCgothic

I think this means that the operational award of $2.6B is being increased by $900m ($300m per) to $3.5B for 3 extra flights. The total of all awards to SpaceX for commercial crew prior to this was $3.145B.

This one: Current status unknown.

Ukrainian govt says it will be rebuilt: If they can.

Confirmed destroyed:

To add to this, in pressurised water reactors like PWR and VVT the coolant and moderator consists of water. Water is also a neutron shield, so the fuel rods need to be placed close together so that the neutrons can interact before the water absorbs them. This dense placement means that there isn't space to individually seal each fuel channel. In order to refuel the core the entire top of the pressure vessel is removed whilst the reactor is inactive. So refuelling is a big job only done occasionally during so-called "outages". In graphite moderated reactors like Magnox, AGR and RMBK, a large proportion of the water is replaced by graphite. Graphite is not a neutron shield, so the fuel channels are spaced further apart and individually sealed. A specialised fuelling machine can lock onto the top of the reactor and exchange fuel rods without dismantling the core pressure vessel. In theory this means the reactors don't need to be shut down for fuel exchanges to take place and "outages" are unnecessary. It also means partially burned plutonium containing fuel can be extracted without stopping the entire reactor. The AGRs never really got this working unfortunately, as gas dynamics during the extraction process caused the fuel rods to vibrate and shatter during tests. This seriously affected their commercial viability compared to PWRs. AGRs are physically much bigger and have complicated fuel handling arrangements. If they also still have to have outages then the main tradeoff has failed. RMBKs were just a bad idea. Unlike AGR and Magnox, they were water cooled which provides what's known as a positive void coefficient. If a little water gets too hot it boils, forming voids which don't shield as much, so the reaction increases, so it gets hotter, so more voids form. And RMBKs were filled with a liquid which could explosively vaporise. AGRs and Magnox were cooked by gas. It can't explosively vaporise because it's already a vapor. And unlike PWRs, in RMBKs there's a separate graphite moderator. The moderator is what catalyses the reaction. In a PWR of the water boils the shielding is lost, but the moderator is also lost, so there's no net gain. RMBKs, AGRs and Magnox didn't operate with secondary containment. In water cooled reactors if the steel pressure vessels were breached a crack would rapidly less to complete failure. Secondary containment is required to contain and quench the steam that would rapidly boil as the pressure keeping it liquid is lost. AGRs and Magnox had concrete pressure vessels. These would just leak mildly radioactive gas if they failed. The gas can't vaporise again, and there's an emergency supply of gas to back fill any losses. The reactors would be powered down, depressurised and a repair made without a gross failure. RMBKs... Yeah, they really needed some secondary containment. Concrete primary or secondary containment is extremely sturdy. Airliners would probably bounce off without causing significant damage (although AGRs would be vulnerable if the fuelling machine above the concrete structures were damaged whilst connected to the reactor - they'd leak substantially through the damaged standpipe). Concrete containments would not stand up to bunker-busting bombs however.

I think the plant was incidental. The Chernobyl Exclusion Zone was just something that had to be captured to secure a route to Kyiv.

Glad to hear

Whilst Chernobyl units 1-3 have been defuelled, the highly radioactive graphite cores remain, and could catch fire if exposed to air and ignited, say by a bomb. Unit 4 does still have nuclear materials present. Fision is unlikely to restart, but the remains of the core would still be flammable and the result would be much more radioactive. A fire started in any of these cores by a bomb would necessarily be accompanied by a large beach of containment. This would not be good. Without a nuclear meltdown ongoing it may be easier to extinguish burning cores. In the middle of a warzone, that would make it harder. Bombing them would not be wise in any case. Russia is downwind of Ukraine. Other than decommissioned Chernobyl, there are currently 4 active nuclear plants in Ukraine. It's unclear how these would react to a prolonged grid disconnection. It would depend on the ability of the staff to start and supply the generators. The staff could flee, the generators could be damaged, fuel supplies could be hard to come by. The UK's AGRs could withstand natural convection cooling for a substantial period. PWRs generally can't. RMBKs are a denser graphite core than the AGRs. I'd lean towards "can't" if there are any of those still operating. A PWR overheating would probably go like Fukushima. An RMBK would also catch fire, but probably not explode like Chernobyl.

Reports are coming in that Yozhnoye Design Office in Ukraine has been destroyed. This is where the Antares 1st stage was made. Embargoed RD181s are now the least of NG's problems.

I agree that reuse is the absolute best application of Starship. The context of this little analysis was a thread on r/SpaceLaunchSystem that one again suggested SLS was the only vehicle capable of lofting it and co-manifesting cargo. My thought process went: 1) Well doesn't Starship have comparable TLI throw? You could put Orion on top of an expendable variant and comanifest roughly the same payload. 2) The LAS would cover the abort mode everyone always complains about. Probably massively oversized for a liquid booster anyway. 3) Oh wait, Starships's had an upgrade (Starship Launch System Block 2?). Huh, that's a lot of payload. 4) Forgot to trim the dry mass. Wow. 5) Haha with expendable Superheavy payload goes lol. 6) Wait, that would cost how much? (Not much). I agree 10% payload fraction would be unprecedented. But all the ingredients are there to surpass Shuttle. The squared cube law is beneficial to large vehicles and Starship Superheavy is 2.5x as massive as Shuttle at liftoff. The tank faction goes down just by benefit of being larger. Then take away the heavy insulation of the external tank, the poor staging strategy that lugs that tank all the way to orbit, the poor TWR in the middle portion of flight and the draggy cross-section. Also recall that 2/3rds of Shuttle's propellant is solid propellant burned at over 100s less ISP than Raptor. The fact that Starship is revolutionary on so many levels is just so exciting!

That 200te payload to reference orbit figure is ridiculous. At 80te dry and 35t reserved propellant that's 315te mass to LEO. Now expend Superheavy for the ~40% payload boost. 525te to the reference orbit. Strip down Starship to just what's needed to acheive orbit. 50te. No reserved propellant. 475te pure payload to the reference orbit. Ridiculous. Swap out some of that payload for 305te of propellant. Gets 170te through 3200m/s to TLI with 375s ISP. In a single launch. Truly ridiculous. And the long-term goal is to reduce raptor 2 to under $1000 per ton of thrust, so that's under $250k per engine. Call it $500k each by the time we're launching the mission just suggested. That's $21 for engines. Plus some pretty cheap stainless steel hull, but let's be conservative and add the engine cost again. $42m for engines and hull. Plus avionics. Let's vastly overestimate and add the entire internal cost of an F9, +$15m. That's $57m. And just to be absolutely sure all launch services are provided, even though we don't have F9's recovery expenses, let's double that again and round up. $120m dollars. For a booster that can put Orion, *plus* nearly 3 times SLS block 2's TLI throw on a mission to the moon in a single launch. That's an SLS block 1 plus 3x SLS block 2s. In a single launch. For ~$120m dollars. Instead of ~$12B. Truly, truly ridiculous. And by ridiculous I mean utterly awesome. (I initially typed incredible, but the most incredible thing about Starship is that by now it really isn't. And all this without reuse.)

This is not the case. There's just been little incentive to have an independent crewed capability beyond putting work towards strategic industries. With Russia behaving in a hostile manner in other matters that may provide enough incentive to develop a separate capability. Or it may not. In any case I don't think buying Russian vehicles would addresses the independence issue.

I like it!

And staff willing to work at wages commensurate with that price point, apparently.

ULA is not a happy company:

I reckon it's because Atlas isn't available and Vulcan isn't accredited.

Probably best to disambiguate by saying "highest exclusively earth-centric orbit for a crewed mission".

No sense in risking the ship.

There could be an inflatable airlock in place of the Cupola. I lean towards an entire depressurisation, but having the entire crew in EVA suits for the duration of the EVA seems kind of unweildy.

Well the highest exclusively earth-centric crewed mission was Gemini XI with an orbit of 1368km x 298km altitude. I believe the highest circular crewed mission was STS-31 at 615x613km (briefly 621km).

Wow!

150t with full reuse is *vastly* more than 68t expendable.

Also if you don't get the rocket back to analyse, your ability to update is limited to what you can assess from telemetry.