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by SJMG 20 days ago
I'm concerned about the cracking clearly visible on the heat shield tiles. It doesn't bode well for rapid reusability.
4 comments

I thought the tiles were designed for easy replacement, so not a big concern with replacing cracked ones.
The tiles ablate. The shuttle returned from every mission with missing tiles.
Shuttle's tiles not being durable as hoped is what killed it's turnaround time.

The problem was never solved and turned what was supposed to be a few days into weeks or months. Every mission the shuttle had to go back into the assembly building and have all tiles inspected and potentially replaced.

Shuttle tiles were also unique per position and starship tiles have a few base forms that are interchangeable
I would also believe that a robot could inspect and replace tiles a lot faster than humans.
Shuttle tiles were also bonded to the body, which I don't believe is the case with most of the Starship tiles.
I thought Starship has many unique tiles, they ended up needing to vary thickness to match heat patterns to save weight and have some complicated geometry near the fins.

Shuttle had more unique perimeter shapes, but starship still has a lot of variation due to tickness. I don't know if that is easier to vary in production or still needs custom molds for the variation.

Total 6 shuttles built over 35 years. SpaceX already crashed 12 over 5 or so years.

Obviously doesn’t guarantee they’ll find solution, but fast iteration will definitely help.

The tiles are not supposed to ablate - they're supposed to be ~fully reusable. That said I think it's plausible that the much higher iteration speed and lack of a need for human-rating (at least during reentry, for now) will allow for more success than the space shuttle saw with its similar approach.
The shuttle required long expensive refurbishment after each flight.
Just made me realise, this is just like the F-35.

Its turn around time is ridiculous, it has to be maintained with specialized equipment/hangers, along with external contractor assistance.

Compared to the Gripen, as an example, which can land on a freeway and be up in the air again in a few minutes.

One was designed to be used in war, in desperate scenarios, with no ability to coddle it. The other, the F-35? Is designed around milking the taxpayer as much as possible, and employing people in as many politician's states as possible.

The shuttle was like that, I think. Which is really sad.

The F-35 is designed to be able to break into and defeat modern air defense networks.

The gripen is a much less capable non expeditonary platform designed to maximize asymmetric losses if sweden is invaded. As a small country sweden has to follow a porcupine strategy to deter invasion.

Presently the actual comparable to the F-35 is attritable drones, which is why every mid-size and major power is developing them.

The Russians have been trying to use attritable drones for years to break down the Ukrainian IADS and have not yet succeeded. Meanwhile the Israeli F35 fleet with no direct American support was able to crack open Iran’s air defenses at the start of the Twelve Day War with relative ease.
Israel used long range air launched ballistic missiles (ROCKS) and cruise missiles, mostly from F15s, to degrade Iran's ancient radar network and S300s (which allegedly weren't moved around much). That was before the invasion, so Iran didn't have much long range radar coverage when the war started.
The shahed/geran is just a low cost cruise missile. The f35 comparable is a loyal wingman that does manned/unmanned teaming and carries A/A and A/G.
>Its turn around time is ridiculous, it has to be maintained with specialized equipment/hangers, along with external contractor assistance.

>Compared to the Gripen, as an example, which can land on a freeway and be up in the air again in a few minutes.

I have no idea where people got the idea that the F-35 requires a major refit after each sortie or that it needs climate controlled hangars, but there's literally no truth to any of it.

The turnaround time for an F-35 after a mission in a wartime scenario isn't going to be much different from any other older fighter jet. Refuel, rearm, get back in the air.

One of the key requirements for the F-35 programs was to minimize extra care needed for the RAM (Radar Absorbent Material). Unlike older stealth aircraft the F-35's ram is "baked in" to the aircraft skin, rather than being a coating. The F-117 and B-2 require climate controlled hangars because their coatings are old and delicate, the F-22 doesn't, but needs regular touch-ups for its coating, the F-35 is just left sitting outside most of the time regardless of where it's operating, a desert, the arctic, a jungle, the deck of a ship, you just leave it out there. The only common maintenance done on the F-35's RAM is replacing a relatively small amount of special RAM tape which is usually used around the edges of the access panels which are opened for other types of maintenance.

I think there's also some exaggerations about the differing highway landing capabilities of various aircraft. [1] is a video showing Eurofighter, F/A-18 and F-35 all landing on a highway in an exercise. Capability with stores and fuel load is another thing but I've read material that doesn't find the contemporary aircraft drastically different in that regard. Now, maintenance hours per flight hour and general operability certainly are interesting topics and there could be large differences.

1: https://www.youtube.com/watch?v=kKbgtixpfIc

Landing is the trivial part, though the USAF traditions of "FOD walk" do seem funny to air forces where donations you found out the aircraft spent whole day flying with maintenance toolkit left in intake.

The maintenance is the real difference - US specifically USAF gear is designed for nice air conditioned hangars to do regular maintenance, Gripen, MiG-29, and to way lower effect F-18 (when compared with F-16) - the first two assume forward bases without ability to do major maintenance, and even the latter (and other carrier adapted ones) promote things like quick swap engines because that's no space for hangar queen to have deep engine maintenance just so engine vendor can claim long time between overhauls

The main reason the Mig29s have a reputation for easy maintenance is because they don't replace parts, they just throw away the whole airframe. The structural and engine service life is like 1/10th that of western fighters.
The Gripen is a light multirole aircraft like the F-16. The F-35 is a stealth strike fighter. It requires another level of special care to maintain its stealth performance. If you want mass-produced stealth aircraft, that's what's required. Stealth aircraft up to this point have been in extremely limited numbers at astronomical costs.
The f35 has been produced in sufficient numbers that its purchase price is lower than that of 4th Gen fighters. The maintenance cost is higher though.
True, its really the first mass produced stealth plane. Everything before it has been in pretty limited numbers (even the F-22 didn't break 200). We definitely could build a new non-stealth fighter that's cheap to build and maintain but that's like saying we should design a new incandescent lightbulb, the money spent on development just isn't worth it over just building more F-35s.
Gripen will not be able to fly higher than tree lines in zones with active anti-air. Russia can't really use any of it's air power in Ukraine war, for example.

F35 can actually do something in such scenarios, as detecting them in the first place is hard.

Russia can and did start the war with using airpower but stopped due to losses. Currently Russia is using its airpower to lob guided bombs which is effective due to the limited range of ukraines missiles. They have nothing comparable to the R33.
Agreed and specifically in the case of the Gripen the “test condition” was “Needs to be serviceable by a few conscripts working under the direction of one person who knows what they are doing”.

It’s an extremely different design goal, the US doesn’t mind exotic weapons that require exquisite (and expensive) methods of servicing, they have the budget and the assumption that a well equipped air field will be immaculately maintained.

Meanwhile the Mig-29 designers assumed it’d operate from damaged/poorly maintained fields, so on the ground you can shut the primary air intakes and it uses ones on top of the plane to get air, drastically reducing the FOD risk on taxi/takeoff.

I do wonder how well the F-35 would fare in an actual shooting war against near peers when all the peacetime assumptions breakdown.

That's a reason the Mig-29 is no longer in production. Point defense fights are obsolete.

The F-35 was just in a war, in Iran. It performed as expected and was able to roll back Iran's air defense network in days.

>It performed as expected and was able to roll back Iran's air defense network in days.

"Rolling back" Iran's air defense seems like very fuzzy phrasing. Certainly, Iran was not able to close its own airspace, nor prevent ongoing airstrikes on many American and Israeli targets. At the same time, my armchair observation is that a great many US and Israeli airstrikes were accomplished using stand-off weapons [1], which would not have been needed if the United States and Israel had achieved 'air supremacy'[2] as has been the case in America's conflicts in recent history.

The observed trend in USAF readiness has been downward for some time [3][4]. Air war is more than single sorties. If you have anything resembling an accurate summary of sorties flown, targets successfully hit, and number of combat-ready aircraft throughout the (currently on hold) war, and so on, please share. Absent such detailed information, all we have are various degrees of speculation.

1. https://news.meaww.com/us-used-tomahawks-himars-standoff-wea...

2. https://en.wikipedia.org/wiki/Air_supremacy

3. https://www.airandspaceforces.com/air-force-mission-capable-...

4. https://havokjournal.com/culture/military/the-hidden-erosion...

    > an actual shooting war against near peers
Who could this be? I can only think of Russia or China.
Well, every mission that it returned from it had missing tiles. That is not the same thing as returning from every mission.
Starship’s tiles are not designed to ablate. They are intended to last multiple flights.
That wasn’t cracking.
I mean ... step 1 is probably fixing the part where it lands in the ocean, falls over and explodes. Once they've done that and can get their hands on the tiles I'm guessing they can continue to iterate there until they get a more easily reusable design.
That part was intentional
Dang, a random HN user solving all the world's problems yet again, what would humanity do without you random HN guy?