RCgothic

Apollo 9 was entirely in earth orbit, as would be this.

That's certainly the direction I'd go. Or maybe Starliner to throw someone other than SpaceX a bone.

Orion to starship in LEO would be a total waste of an SLS.

Factually nothing to do with IFT-3. The dismantling was noted on March 12th and IFT-3 was the 14th. https://x.com/_mgde_/status/1767547040089657675?s=20

Or these are just teething troubles as they discover what's vulnerable and better protect those bits; pad turnaround is getting faster between each flight; and they're going to have three or more pads to launch from.

There's not a shred of evidence IFT-3 was anything other than a completely nominal flight until SECO or that raptors operated anything other than exactly as intended to achieve the final trajectory.

Ablation and corrosion are types of wear - material thickness or effective thickness reducing by physical or chemical action. I've also always found it weird that "no endurance limit" is not actually a good thing.

Isn't this basically a substantial part of the reason DIVH is getting retired? The pad infrastructure is old, complicated and creaking, and DIVH doesn't fly often enough to make it worthwhile to keep everything fully tested and operational between flights. Then when they do come to launch, something has inevitably failed and needs fixing.

It's certainly theoretically possible to protect bridge piers from collisions. But in the specifics of cost/obstruction of navigation channel/river bed conditions it may not be practically possible to adequately defend every existing bridge. If I were a security agency I'd be pretty nervous about deliberate follow up attacks right about now.

It took over 3 years for Falcon 9 to get flight cadence to under 3 months from the first flight. Starship not doing badly.

IFT-1 pad destruction was likely as a result of a steam explosion from vaporised groundwater boiled by exhaust gas penetrating the cracked slab, argues a new paper: https://arxiv.org/abs/2403.10788

No, the causes of the losses of control on both booster and ship are unconfirmed.

I don't think even a cluster of 40N thrusters is going to be anything even close to powerful enough to manoeuvre a potentially 2,000,000+ kg refilled V3 ship.

"Constantly Exploding Nuke" is a very poor descriptive term. It's a nuclear reactor. We have plenty of nuclear reactors that deal with the heat produced by energy released. Nuclear saltwater rocket engines are a type of reactor where the fuel is suspended in the propellant and made to undergo a quick reaction in a chamber before the nozzle throat. The heat of the nuclear energy released is carried away in the propellant exhaust.

Scott Manley points out around 8 mins into his video recap, vapours in the payload bay, then getting vented as the payload door opens. Very cool!

I think the biggest concern is lack of attitude control. If you can't control attitude you can't control re-entry burns, and for the largest single object ever placed into space that would be a problem. I can see a repeat of IFT-3 for IFT-4. Don't want to go orbital until you can demonstrate ability to bring it down again, or it could come down anywhere. The amount of shed debris in video was also a bit concerning.

Failure of a vehicle to supply conditions condusive to raptor firings is not the fault of the raptor and it's unhelpful to insist otherwise. Distracts from the actual causes, which in these instances appear related to failures with the grid fins and tank vent RCS systems, both of which are only getting their first full up tests this flight.

Yeah, it'd lost far fewer tiles on ascent than last time.

Both booster and ship appeared to have orientation hold issues. Instability would also account for the skipped on-orbit burn. Maybe they thought there was a chance the fins could regain control on re-entry, and it almost looked like they were stable towards the end, but I'm not sure. In any case, primary mission success.

I'm not sure what they could have done to do better, but ultimately 5/7 of their Rocket 3 launches was pretty bad. Sounds trite, but if they'd been successful they'd have been successful.

My 4th year project at university was research on the subject of generating ultra-high strength magnetic field with electromagnets. Firstly, it needs a lot of windings. The more loops for a particular current, the higher the magnetic field. It doesn't seem to me that molten iron is especially condusive to compact windings. Secondly, resistance tends to go with temperature, and specifically drops to zero in certain materials at ultra-low temperatures.There's a reason super-high power magnets are generally cooled with liquid gasses. Molten iron, again, is not condusive to a low conductive resistance. Thirdly, the hoop-stress in the material is key factor. Magnets want to disassemble themselves and fly apart under extreme tension. Molten iron contributes nothing to the tensile strength of the material. The research found hoop stress was related to the thickness of the coil. Nesting multiple small coils could potentially keep the stress down. Again, Molten iron a pretty poor choice. Finally, the reason planets can generate enormous magnetic fields is because they themselves are enormous. Just having rotating iron isn't sufficient, you'd need to seed the iron with charge and/or a starting magnetic field somehow, and see above for all the reasons solid cold materials are a better choice for that. For all the power of planetary magnetic fields, they're pretty inefficient for the masses involved. The right combination of eddy currents and movements eventually create a self-sustaining feedback loop that generates steady magnetic fields. But even sunspots are only ~3000 Gauss (Jupiter is about 4 Gauss). MRI machines regularly generate 70,000 Gauss, and we can create 450,000 Gauss steady state magnets in labs.

And Astra goes private after losing 99% of its value: https://arstechnica.com/space/2024/03/after-astra-loses-99-percent-of-its-value-founders-take-rocket-firm-private/

Astra warn of imminent bankruptcy if reduced offer to take company private isn't accepted: https://arstechnica.com/space/2024/03/rocket-report-astra-warns-of-imminent-bankruptcy-falcon-heavy-launch-delay/

https://www.cnbc.com/2024/02/26/faa-closes-starship-investigation-spacex-seeks-next-launch-license.html IFT-2 investigation has been closed. Edit: Sorry, Monday's news. May have missed this being shared earlier. Only 17 corrective actions is a marked improvement on IFT-1 which required 63.

I think the idea is that ICPS is only 32 tons and FH has at least 63t of nominal payload, so looking at just those numbers would end up with a stage that's twice as powerful. Unfortunately the largest monolithic payload a Falcon mission has ever carried is 17.5t, with the rest being propellant residuals in the FUS. With a modified adaptor it might be possible to put up ICPS itself with Orion going up separately, but even ICPS doesn't actually have enough DV to send Orion to TLI from LEO (on SLS the core stage helps, but for a simple rendezvous in LEO there'd be no help). Only SpaceX knows whether they could actually fly a full 63.5t on FH as a monolithic payload. Another problem is that Orion/ESM can't capture into LLO and return by itself. The "kick stage" would also have to do LLO insertion. One option is to put up a full falcon upper stage with 63.5t of residual propellant and dock that to Orion in LEO. That would have enough power to send Orion to TLI, but not to also do the full insertion to LLO as would be needed even if the stage were to demonstrate a 3+ day endurance. EUS has way more DV than needed to do TLI and LLO insertion with just Orion (if it has the endurance), but it weighs about 140t at launch (although it has to do a partial burn to reach LEO with SLS) which takes us back to needing SLS (or starship).