RCgothic

No new block upgrades are planned for F9 or Merlin to the best of my knowledge. F9 will fly until it's no longer economical for SpaceX to maintain production. There'll come a critical point where enough of F9's customers fly on Starship and they'll shut F9 production down. Yes, starship burns more fuel, but you also have to consider the energy and time expenses of always having to manufacture and throw away new upper stages. Starship should also be a lot easier to build and refurbish between flights.

I asked Jonathan McDowell about this. He disagreed. DART is definitely F9's highest energy launch so far, beaten only by FH Demo which as pointed out they didn't get paid for.

One to bookmark:

Good catch. The launch was into a 200km x 270000km supersynchronous orbit, so that's slightly less than TLI, but indeed higher than GTO.

This was only SpaceX's 3rd mission to deep space higher than supersynchronous, after DSCOVR (Earth-sun L1) all the way back in Feb 2015 and Falcon Heavy Demo in Feb 2018. They're rare!

Generally it's weighed with a suitable load cell. If it's too large for a single load cell, you can use multiple lift points with a load cell on each (or a representative leg if the load is reasonably symmetrical or has load equalisers). Or you can apply a known perpendicular load and measure the angle of the dangle. If it's extremely big or awkward, you weigh the pieces and the assembled mass is calculated. Finally, for spacecraft in freefall, you can also calculate the mass from the response to a calibrated input, such as a gyro or thruster.

Yeah, I really enjoyed a couple of articles on that blog. Long reads, but really good analysis.

When I visited KSC as a trek-obsessed teen I was not happy when the tour guide had no idea Enterprise existed.

LEO Labs are now speculating effectively that the ASAT interceptor hit the target from behind at greater than orbital velocity, hence the bias of debris into higher apogees rather than lower perigees. This would mean it wasn't a hypervelocity collision, which has implications for the size and distribution of the pieces. This would be unusual for interceptors, which usually just get in the way of the target. This would mean the ASAT would need to be going at greater than orbital velocity, which seems like a lot of effort to go to for not much benefit to the interceptor. It needs a much larger launcher. There are plusses and minuses. The pieces are likely to be a lot larger and fewer of them, which means we can track a lot more of them as a percentage. This makes avoidance manoeuvres more feasible. On the negative, the higher apogees and larger individual masses means the debris is likely to hang around for longer.

The MoD release is incorrect. According to LEOLab's Gabbard chart, at least 11 items with perigees below the altitude of the ISS (~410km) have already been detected. They estimate 5-10x more smaller objects than this, which because smaller objects can be imparted with more retrograde velocity, many of those will also have low perigees. So there are already probably a hundred new debris items crossing the ISS's orbit. Furthermore, orbital decay will eventually bring all of these ~1500-2500 objects down through the ISS's orbit. Almost all of these will be untrackable, and because the target was in a polar orbit orbital precession will eventually shape the debris field into a complete sphere. So there will be no advance warning of hazards, no possibility of manoeuvring to avoid the debris field, and no specific times in the ISS's orbit where additional precautions can be taken. It's just a risk the station (and any others soon to launch) just have to live with from now on. A spectacularly reckless and ill-conceived test.

Sevenperforce already knows this. What they're saying is that Raptor as a FFSC engine with independent fuel and oxidiser pumps and preburners should already be capable of utilising variable fuel to oxidiser ratios to some degree. Running the main combustion chamber over onto the oxygen-rich side of stoichiometric may indeed require a different construction. And switching between fuel rich and Oxygen rich may indeed not be healthy within a firing unless the changeover is swift.

The hypocrisy is running attack ads "This is ridiculously complex and unsafe!" whilst proposing simultaneously behind closed legal proceedings to do exactly the same thing.

Detailed analysis by LEO. This shouldn't have happened, and even less to a target in a polar orbit. Hard to have more utter contempt for this outcome.

Roasted. Also, what the heck!?

I thought the most interesting details: -Raptor2's a 240mt engine. -Superheavy with 33 engines is 2.2-2.3x more powerful than Saturn V. -Depot isn't just a loitering tanker, it's heavily insulated to reduce boiloff. -Orbital launch Jan/Feb. -A dozen orbital launches next year potentially! -Proper payloads from 2023. I thought he could have done better on suggesting potential payloads however. This blog has some pretty good suggestions (it's a long read from a former member of JPL): https://caseyhandmer.wordpress.com/2021/11/17/science-upside-for-starship/ https://caseyhandmer.wordpress.com/2021/10/28/starship-is-still-not-understood/

Changing engine is not easily done. Basically the whole rocket is designed around the engine choice.

Just for clarity, this is the pre-litigation-delay schedule. "Orbital Flight Test" therefore most likely refers to flight test of the HLS LSS. Assuming everything has been delayed around 6-9 months, and perhaps allowing for SpaceX's schedule being a little bit generous anyway, we can probably expect an Orbital Flight Test of the HLS LSS around Q4 of FY22, maybe into Q2 FY23. The 4/20 first orbital flight test of *Starship* is separate, and will likely be early 2022. The propellant Transfer Test may not be significantly delayed as that would likely occur between regular Starships/Starship Tankers.

ASAT weapons should be considered as WMDs IMO.

Woohoo! January Launch? Fingers crossed! Also this is just twisting the knife, lol.

So were some of the Apollo CSMs I quoted, so fair's fair.

Be fair, let's include a DIVH and Orion for OFT-1. Still. $93B for 4 missions. Reminder that Apollo cost $284B in today's money for 10 Saturn I missions, 9 Saturn 1B missions, 13 Saturn V missions, and 2 Surplus Saturn Vs. #Cheaper #Sustainable #Sarcasm

They'd also have to shorten the bell or lengthen the skirt if the engines were moved inboard as they're mounted on the bottom of the tank dome.

Yes, gimballing only works when the main engines are on. RCS is for control at speeds where aero surfaces are ineffective (e.g. slow on landing) or where there's no atmosphere at all. They're also used to "quench" the gyroscopes when they get close to their limits.

Yes, all 6 at stage sep. It's necessary for the TWR, though they may throttle some SL engines off as TWR improves to improve ISP.

6 Raptors is much more thrust than 4 RS25s, just saying.