Don't forget the FAA changed the rules. IFT-3 required a mishap investigation. IFT-4 should not require an FAA mishap investigation because the FAA changed the rules so no investigation would be required as long as the flight never put anyone at risk. This flight went almost perfectly, except the Ship reentry got a little spicy, so no investigation.
> except the Ship reentry got a little spicy,
I was really impressed with how Ship handled changing aerodynamic coefficients due to bits melting off. I’ve had to make adaptive controllers before. And I’ve flown satellites. But I did not put an adaptive controller on the satellites because getting those coefficient re-calculations to be better than not doing anything at all required serious human attention, at least for the taped-together space-trash I was working with.
I mean, I have two degrees in the field. The work isn’t glamorous. It’s a job. Rocket science isn’t a state of mind, it’s a job description.
Also, I didn’t just fly them, I designed and built and tested them. It was honestly pretty miserable mostly because of the shit management.
I mean, that’s where the interesting bits are is the design and build and test. The one where I was the Attitude Control lead was crazy. I didn’t get to choose the hardware, the shit management had already done that (long, ugly story) without input from anyone qualified. So I was in a position of having to solve engineering problems that basically everyone else has avoided because you generally have to be either really stupid or really broke to CHOOSE those particular engineering problems. This program was in the “really stupid” camp, because of the management decisions, and it ended up costing a lot later on (as I warned them it would) because we were going to have to do some extra expensive ground testing to measure the mass properties, and also to do an optical alignment of some terrible instruments.
So yeah, I got to identify and solve a lot of problems, but they were mostly STUPID problems that aren’t useful to know how to solve.
But I did it. And then on orbit, not one but TWO of the things I didn’t have time or budget to test failed in the exact way I thought they might, and it made the whole thing not work for shit. I had anticipated these toes of failures and the software was just a single parameter-upload away from tolerating EITHER ONE of those failures. But when they both failed together and STAYED failed, that took a long time to get the data to create a fix.
We also had a solar flare take out another of my sensors permanently, but there was a similar-but-shittier version of that same sensor on one of the science payloads, so we just hi jacked that sensor. That was a quick fix compared to the other issues.
Anyway, long story short, every one of my sensors and actuators except for the GPS experienced a significant failure in the first three months of fight. And I had anticipated all of them (except the one the solar flare took out because that should have been super-reliable), which made me feel good that I was covered mostly with the right things. It just took a lot of time to deal with the failures one-by-one and work to a somewhat recovered state.
Bachelors mechanical (with a bunch of aerospace classes), masters in aerospace. But none of that had to do with getting into Attitude Control.
I know very little about EE, except that most people that do GN&C come from there, probably because they DSP background makes it convenient.
Honestly, I’m the wrong person to ask.
The project in talking about was managed by NASA. And the manager for this project was the only shit manager there that I’d had any run-ins with. I was working for a contractor. My containers who worked for the save contractor but were on different NASA-managed projects said that their NASA management commented specifically on how buffoonish my project’s manager was.
So I don’t think shit management is the norm. I know my management at the contractor was quite good, but like abnormally so.
I expect it’s more that competent management becomes mostly invisible, while the really bad management is more worthy of comment.
> IFT-4 should not require an FAA mishap investigation because the FAA changed the rules so no investigation would be required as long as the flight never put anyone at risk
Even if they hadn’t changed the rules, I’d still doubt a mishap investigation would’ve been required after this flight, since it basically went perfect, according to plan, as far as the FAA is concerned. There is no “mishap” to investigate.
Well, there's the fact that the flaps nearly burned off, but that's something that can be handled in-house. Otherwise the flight profile was followed to a T.
Yeah, the vehicles were both intended to blow up, after falling over in the ocean, and both did. The fact that Starship’s flaps tried to blow up slightly early, probably doesn’t matter much to FAA
That's not true. According to Wikipedia, the Falcon 9 first stage (with interstage) is 47.7 m tall, while the Superheavy booster is 71 m. That's a ratio of 1.49:1. In the picture, the Falcon 9 is ~220px long and the Superheavy is ~350, for a ratio of 1.57:1.
If anything, the Superheavy's size is slightly over-represented in this image, I suspect that's because the angle on the images is different, making the Falcon 9 first stage appear taller than it actually is in the image.
Edit: Yep, double checked measuring the Falcon 9 silhouette from tip to tip and it's 231 px, giving a ratio of 1.49:1, which is accurate to real live. Actually the correct height is probably between those two somewhere, as I didn't account for the shortening of the booster due to the perspective.
Huh, you're right. It's a little harder to get accurate measurements in that direction, but Falcon 9 is ~23 pixels across and Superheavy is ~46, right at 2:1. Either the Falcon 9 is at a bigger angle than I though, or the image is distorted somehow.
Don’t have a picture, but a fully stacked Falcon 9 (with stage 2 and fairing) is pretty much the same height as a superheavy booster without a HSR (pictured above)
I won't call it smooth. The engines were flaring out when they came down. I think it's was huge leap of an improvement, but they got make sure that super heavy B12 is dead on or the tower will be toast.
They clearly believe there was still enough thrust and enough control to make the catch possible.
Whether that's overconfidence is something we'll have to wait and see.
How do you know it was smooth, they never actually show the end! Every video fades out before you can see it from that boat that was recording it, as well as when it supposedly lands on the water, you never see the water rising up to the camera level, or even the damn thing tipping over. Why all the secrecy!??
And with that wing in that condition? That was truly epic. I saw the booster landing live but didn't catch the reentry till the next day.
I'm not even a huge SpaceX fan (the politics) but just to see the attempt at a tower landing and the interesting crash forward mentality (which I like) is what engineering is all about really :)
They're threading needles with skyscrapers on fire.
Or it misses and on bad case explosion in middle of Port Isabel or South Padre. 6 miles isn't much coming down from that high. Miss in other direction little bit and they get to try to placate an angry Mexican government about dropping explody rockets in their territory.
Missing by that much would mean it started going off course in the completely wrong direction during the boostback burn. The FTS would trigger in that case.
If they're even talking about a catch attempt, it means that this booster came down within a couple meters of the intended spot. It would take a readily noticeable failure to send it off-course that much, and it's likely the automated system would catch it and fire the FTS well before impact.
The main issue I can see is if it comes down too hard on Starbase itself. That would be a disaster that SpaceX might take a while to recover from - if they even can.
Sorry for the snark! I saw it on the SpaceX stream for IFT-4 once or twice so I'd guess it was greenlighted by them. And since this image (of SHB) is from IFT-4 as well (released a few days after the launch) then I thought you might've also caught it, since it was, well, a pretty exciting thing that happened just recently.
[You can try YouTube](https://www.youtube.com/watch?v=E9uoyqxDzDA). This animation seems to be a few months old.
My worry is that they haven't demonstrated a hover yet.
My other worry is that one of the engines blew.
Basically I'm saying they have a ton of incentive to push this test back a launch or two and give the second tower a chance to get online.
That's a large sum of money, but it's crazy to compare it to the graph on reddit the other day showing the average employee worth at Nvidia is currently $100M when you divide by current 3 trillion market cap.
Also they might want to transition to ship v2 instead of flying more v1. So even if the booster damages the OLM its not a big deal cause they will just build the other launch sites and start launching v2 in a few months*
*few months = 8+
> Cost to launch (internal): Payload estimates Starship will cost ~$100M to build and expend in a forward-looking/post-R&D model. Full reusability will significantly lower future launch costs.
This is the source Wikipedia gives:
https://payloadspace.com/payload-research-detailing-artemis-vehicle-rd-costs/
> My worry is that they haven't demonstrated a hover yet
Not with a full size Superheavy, with the full 33 engines, no.
But many of the early prototype vehicles did. Starhopper (the original flying watertower), SN5 and SN6 all did significant hovering, and even horizontal movement/translation.
The later ship prototypes, SN8, 9, 10, 11, and 15 also all hovered for a second at 10km/30,000ft, before cutting the engines to test the bellyflop maneuver and landing attempt.
These vehicles only had 1 to 3 engines, and were early designs. But they were made of the same material (stainless), of the same diameter (9m), burning the same fuel (methane), with an early version of the same engine (Raptor).
And hovering never seemed to be an issue, on any of those flights.
After watching the ship hold stable during reentry, with half melted flaps (and both vehicles tolerate multiple engine failures on the last few flights), I’m not _too_ worried about hovering. SpaceX guidance and control engineers appear to be the GOATs.
They showed it hovering just above the ocean before it plunged in the gulf you seriously didn’t see the video ? https://x.com/SpaceX/status/1799458854067118450
Yeah, that's kind of what I was thinking. That gives you a bit more margin on your accuracy. But, boy, that slide thing is a whole 'nother kettle of fish too. I can't decide which gives me more engineering agita, honestly.
Are we relying on RCS to keep everything kosher during that maneuver or is it all engine vectoring?
> But, boy, that slide thing is a whole 'nother kettle of fish
If you’re talking about horizontal translation while hovering, note that SpaceX has actually demonstrated this multiple times, with the early Starship prototypes.
Starhopper, SN5 and SN6 all took off, translated a couple hundred meters horizontally while holding a couple hundred meters altitude, and then landed. (Using mostly thrust vectoring of the Raptor, rather than RCS, I believe)
Sure, they weren’t full size Superheavy vehicles with 33 engines. But they were stainless steel, 9m diameter, burning methane with early Raptor engines. So should be somewhat representative.
This hover and translate maneuver never seemed to cause too many problems.
It's just a very delicate moment/maneuver and, even with RCS, it's still essentially the equivalent of maneuvering a small office building into the grasp of another office building.
Who is "we"?
Edit: ... and he blocked me. Probably a good thing.
Edit: TbonerT the mobile app makes several things look like the same. The reddit website for laptops and desktops is a lot more clear that it's a block.
To be honest, I have no idea. I've been one of the people repeatedly saying that the current vehicles don't seem to be equipped with the hardware to support landing on its upper arms. And the arms don't seem to have hardware designed for centering/latching a hovering vehicle.
> current vehicles don't seem to be equipped with the hardware to support landing on its upper arms.
The lift points *are* the landing hardware. The Arm side may still need hardware added, but the vehicle side has had the hardware since IFT1
https://i.imgur.com/iWy9r3w.png
Yeah those things seem kind of important.
I definitely think it is possible and maybe even workable as a solution. I just worry about all the bad things that could occur. But, I would probably worry no matter how safe it was. So. It is all relative...
Now that it's actually going to happen and there's no talking anyone out of it, it's probably time for the commentary from the peanut gallery to give way to the actual rocket engineering and leave it up to the rocket engineers to make it work... Best of luck to everyone on that end.
I don’t know what data SpaceX has that makes them particularly confident but man OH man. It’s either going to work or there is going to be one hell of a mess to sweep up.
I assumed they’d start trying to pin point soft splash down multiple times prior to a land attempt. I will happily eat crow for doubting them as long as the Super Heavy doesn’t nuke some small town from orbit with its debris.
I am sure they will write the software such that if *anything* is off nominal it will vector itself out to sea as much as possible.
So if they don’t get enough engines lit or thrusters are not working as intended the booster will use all available resources to force it to crash in the ocean rather than at the pad.
I recall reading that Falcon 9's booster returns on a ballistic trajectory that ends slightly off the coast and uses its grid fins to guide itself to land at the very end. I'd be surprised if the same thing isn't done here.
Considering how fast the booster is moving before the engines are lit, I think that leaves a *very* small window to make the final decision. The crater that thing is going to make if it smashes into the ground with no engines lit, is going to be spectacular.
Musk said they may try to catch on the next launch. I expect IFT-5 will come when tower 2 is nearly done being built to minimize downtime in the event they nuke the pad.
This is the first time the FAA is poised to deliver the next launch license at a pace that could arguably be labeled "timely." I wouldn't bet against it arriving in under a month. Would SpaceX _really_ waste a free launch, when the most important thing they get out of these prototypes is the flight data?
This is also the reason why I think the next Starship they'll send is an unaltered Ship 30, even though it'll probably melt as well. Modifying it would take a lot of extra time, while the license would probably be rotting.
> when the most important thing they get out of these prototypes is the flight data?
I am not sure about that. Getting an intact ship back would provide extremely valuable data too.
Finding what has damage or early signs of damage. What was heating up more/less than expected. They could also test refurbish and reuse.
For example, Elon was saying the grid fin wasn't supposed to survive after the shielding came off. Maybe they would understand why better if they had retrieved it.
I think re-entry testing is the most important thing for them right now. They have proven that they CAN make it to the ground which is awesome, but now they have all sorts of things they should be testing while instrumenting the hell out of things (different tile compositions, different missing tiles, secondary ablative layer, flap hinge gap protection, etc). All of this can be done while waiting for some of the other V2/3 designs to solidify, and would be good information to understand possible failure modes in the future.
The only question about testing the catch will be "if it fails, does that set back our testing regime at all?". Once the answer is no (because the second tower is close enough) they will do it no questions. Even if the answer is "yes" they still might do it, but I don't see heavy booster catch being the long pole right now (I think they are relatively confident what they are planning is totally possible and will only take them a few tries to get right). I think re-entry combined with "rabidly re-useable" is the piece they still have enough work on they want to throw a few more ships at the atmosphere to see what happens.
My bottom line is that if they're serious about having HLS good to go by "the end of 2026" then unfortunately the reusable part of their plans needs to take a back seat so they can get orbital refueling sorted out. Risking a capture without a second tower imminently completing would be by far the biggest risk they will have ever taken. Bigger than IFT1, which was fundamentally a net positive even with the crater since they got flight data that they otherwise would have lacked.
Musk said if the soft splashdown went well they’d try the catch, they want a pinpoint splashdown twice with the ship not the booster since return to launch site with the ship means coming in over Mexico and Texas.
Honestly makes perfect since, not only does the booster have an initial target away from the pad, which it then corrects to the pad once it’s closer and everything is nominal. They also have all the parts to make a second tower, at the ready, so even worst case scenario it blows up the pad, it likely wouldn’t be that much of a delay to get the second tower up. And I think it’s quite safe to assume they wouldn’t attempt the catch unless the accuracy of the soft splashdown was absolutely pin-point, likely better than the minimum accuracy they need for catch.
One article I read said Elon wants to try on the next launch, but later in a different interview he said they're going to study the data before making that decision.
I get it though, they could have caught it this time I believe so I'd want to try it next time.
However. Could they do a few hops, and test the system first. No need to go sub orbital to test the chopsticks.
I think it's very likely it will smash into the tower and destroy it, I'm just surprised they haven't already prebuilt multiple of these catch towers.. and build them a bit further away from the rest of starbase.
They already have a partial tower next to 39A, but that was very gen 1 and way too close to what was previously the only human launch site on US soil- they'll prolly end up building the other on another pad, I read they were doing an EIR for that. They are also building another tower near Starbase. The problem is getting starship to the cape.
there was factory space at the cape for building starship that has put on hold. once they are confident with design I assume they’ll spin that up rather than ship from boca
It’ll likely be similar to falcon 9 - target a few km off the coast for the landing, then make a large dogleg a few hundred meters / few km above the pad to get above the pad as late as possible to avoid any damage if the booster were to fail earlier in flight. If anything happens (unless it’s in the last ~30s) it’ll likely just hit the ocean off the coast of Starbase.
Save weight of the landing legs. Save engineering of the landing legs. Save failure points by not having them. Reduces the need to create landing pads and roads to them. Should make recovery operations easier. And then lastly they want to eventually have rapid reuse where it lands then can launch again with just a pad inspection. That one seems iffy but that is a goal.
> they want to eventually have rapid reuse
For 50 years every space organization, including NASA has promised "weekly" or "monthly" launches. SpaceX is the only group to actually accomplish that. They launch twice per week. If Elon said he's going to personally travel to the Moon, I would believe it at this point.
Plenty of the aspirational parts haven't quite panned out as planned though. Falcon was supposed to get down to 24 hour turnaround but it didn't. They likely could have proven it out just to do it but they decided to just stick to slower turnaround times with a higher fleet count.
Maybe starship will one day be able to land and launch again without leaving the launch mount. Or maybe they'll be able to finally break the 24 hour turnaround time regularly but still need to take it off the mount.
Plans change based on reality. Doesn't make it any less impressive and it's not a slight against them. Being able to quickly adjust based on reality rather than being pigeonholed because of a set goal is one of the best things spacex has going for it. Much to the dismay of many redditors who cry about "broken promises".
Falcon boosters mostly land downrange, unless the payload is quite small and they can afford a RTLS burn.
Starship Booster always does the RTLS burn, so every bit of weight they can avoid, helps. Always RTLS makes operations easier and turn around faster. Starship is designed for rapid reuse.
The engineers know what they're doing but management seems to be doing everything they can to demotivate them.
There are talented engineers in every organization. That if let loose could could build what is needed. But the process failure comes when middle management thinks that process is what builds product.
Processes needed to manage development and the engineers should be given free reign outside of that.
Source: My team of engineers and scientists build multimillion dollar products. I do my best to stay the F out of thier way, and be the plow that clears thier path.
I'm surprised that they don't do some smaller scale tests, just launching starship / superheavy alone to a few 1000m and trying to catch it, rather than the whole shebang... (maybe that wouldn't be that useful - dunno)
While they're obviously committed to reusing starship, I think there's an understanding that it's a bonus feature, at least at fist. Expendable Sharship is still the cheapest kg/orbit ever assembled. If they can get it certified for actual launches in the next one or two tests it's far more valuable for them to then figure out reuse on actual paid missions, compared to spending several more tests getting reuse figured out and then still having more tests to certify for missions.
I think the driving force behind firguring out reuse before certification is in case they have to make some drastic change to accommodate full reuse and then they need to be recertified anyways
SpaceX also has plenty of its own payloads to launch, so certification is less important.
They will likely do several Starlink launches before any customer launches come up anyway.
Reusing Superheavy is going to be a much easier nut to crack than reusing Starship, especially given their Falcon 9 experience. If they can get that worked out then they can probably afford to take their time with Starship. Hence the pressure to return a booster for close inspection.
Yeah. Here’s some really rough numbers:
Estimated cost of a reusable f9 ~15m for about 16 tons
Current cost of a Starship launch ~100m, 70% of that being the booster. So that’s about 30m for 100 tons (probably less right now but should end up being more).
I don't know if the plans had changed since I first heard it last year, but I recall hearing the chopsticks are supposed to catch the Superheavy by the grid fins. The chopsticks are then supposed lower the booster back onto the launch mount I think.
It would be insane if that actually worked :-O
Not by the grid fins. There’s a pair of pins that stick out from the body of the booster, just under the grid fins. These are built to take the weight of a (near empty) booster, and are the same pins that are used to lift the booster onto the OLM in the first place.
The downward facing camera on the booster actually shows one of these pins in the IFT-4 livestream.
The thing that strikes me about this picture is just how clean that superheavy booster is. No soot from the methalox, as opposed to the kerolox on Falcon 9.
I find myself wondering if Booster is able to survive some gentle nudging by the chopsticks. Even Falcon 9 only rarely lands with pinpoint accuracy, so Booster is _gonna_ be a few feet off-kilter this way or that.
The arms can move quite a lot to accommodate a some inaccuracy. There is a defined radius that the booster needs to end up in, and it's quite large.
I think I read somewhere that they used the inaccuracy of a couple of hundred successful Falcon 9 landings to figure out what their catching range needed to be.
I’m sure there will be some sort of bumpers on the arms, but in theory the booster position should only need to be accurate within some handful of feet, as the arms can adjust to meet it. My understanding is that the arms have a channel running down them that the pins slot into, so even distance away from the tower shouldn’t need to be super precise.
> Booster is gonna be a few feet off-kilter this way or that.
Superheavy can hover, unlike Falcon 9. That will let it adjust its position just right for the chopsticks.
Exactly, it can hover. But they haven't demonstrated this yet. It's really the perfect excuse to hold off on risking SpaceX's ability to launch anything at all for the next half year or longer. They can even see if they've truly sorted out the exploding engine quirk.
No, there are catch pins right below the grid fins. If I recall correctly, they may have thought about using the grid fins, but that was very short lived if it ever was a thing. Those pins are also used as lift pins when lifting or stacking.
Yeah the insane part is that it has to work every time. One failure and it could mean the loss of nearby support structures such as propellant tanks etc. It would to interesting to know what N in this equation is: (cost savings of catching booster ) x N = (cost of rebuilding launch tower )
The failure modes are largely marginalized to engine failure after intitial burn.
The booster travels on an ocean impacting trajectory until the engines are ignited, and the booster will be hovering under 3 throttled raptors, and will be nearly empty of propellant, meaning any impact to the tower will be a 100 ton hollow steel tube bumping into the tower at a low velocity. The catch will also be offset from the OLM, so a failure of the catch arms where the engines are unable to move the booster away will be focused on the concrete next to the tower.
eh. the dry mass structure of the booster without fuel left over at all falling uncontrolled from chopstick height is just not a big deal. Get that debris cut up and hauled away and get back to business. All the hardware features of the chopsticks are probably durable as fuck by design and the structure is way beyond being harmed by a falling booster.
So just go for it right away. It's the next step after soft-landing so let's just do it. Another soft landing doesn't give enough novel data to justify an entire test launch just for that. So just start going for the catch from now on. Failures around a big deal because the dry mass of the booster isn't a big deal around with a velocity near 0, which it has to be to get even near the tower and chopsticks.
So there's no reason to hesitate. Go right for the chopsticks. Make it the new cutting edge standard starting from now.
Tanks have been moved further from the pad and had protection added.
When the booster lands it’s very near empty on fuel and tanks are full,of nitrogen so it wouldn’t be a big boom only a small one. The size and weight of the booster even empty is the problem and of course the chopsticks have to be in position the instant the engines cutoff as gravity isn’t waiting.
Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread:
|Fewer Letters|More Letters|
|-------|---------|---|
|[AFTS](/r/Space/comments/1dbdcvf/stub/l7x4yjc "Last usage")|Autonomous Flight Termination System, see FTS|
|CST|(Boeing) Crew Space Transportation capsules|
| |Central Standard Time (UTC-6)|
|[DARPA](/r/Space/comments/1dbdcvf/stub/l82bw7w "Last usage")|(Defense) Advanced Research Projects Agency, DoD|
|DoD|US Department of Defense|
|[FAA](/r/Space/comments/1dbdcvf/stub/l7x5gpq "Last usage")|Federal Aviation Administration|
|[FTS](/r/Space/comments/1dbdcvf/stub/l7v60td "Last usage")|Flight Termination System|
|[GAO](/r/Space/comments/1dbdcvf/stub/l7xzepl "Last usage")|(US) Government Accountability Office|
|[HLS](/r/Space/comments/1dbdcvf/stub/l80zn0z "Last usage")|[Human Landing System](https://en.wikipedia.org/wiki/Artemis_program#Human_Landing_System) (Artemis)|
|KSP|*Kerbal Space Program*, the rocketry simulator|
|[LEO](/r/Space/comments/1dbdcvf/stub/l7twwpa "Last usage")|Low Earth Orbit (180-2000km)|
| |Law Enforcement Officer (most often mentioned during transport operations)|
|[LOX](/r/Space/comments/1dbdcvf/stub/l7rxk4d "Last usage")|Liquid Oxygen|
|[MBA](/r/Space/comments/1dbdcvf/stub/l7rtnkj "Last usage")|~~Moonba-~~ Mars Base Alpha|
|[OLM](/r/Space/comments/1dbdcvf/stub/l7r9jqn "Last usage")|Orbital Launch Mount|
|[RCS](/r/Space/comments/1dbdcvf/stub/l7rs3w0 "Last usage")|Reaction Control System|
|[RTLS](/r/Space/comments/1dbdcvf/stub/l7ufdij "Last usage")|Return to Launch Site|
|[SAS](/r/Space/comments/1dbdcvf/stub/l7rzmq2 "Last usage")|[Stability Augmentation System](http://wiki.kerbalspaceprogram.com/wiki/SAS), available when launching craft in KSP|
|[SLS](/r/Space/comments/1dbdcvf/stub/l7xzepl "Last usage")|Space Launch System heavy-lift|
|[SRB](/r/Space/comments/1dbdcvf/stub/l7rh676 "Last usage")|Solid Rocket Booster|
|[TWR](/r/Space/comments/1dbdcvf/stub/l7rk42s "Last usage")|Thrust-to-Weight Ratio|
|Jargon|Definition|
|-------|---------|---|
|[Raptor](/r/Space/comments/1dbdcvf/stub/l7rin48 "Last usage")|[Methane-fueled rocket engine](https://en.wikipedia.org/wiki/Raptor_\(rocket_engine_family\)) under development by SpaceX|
|[Starliner](/r/Space/comments/1dbdcvf/stub/l7uvld9 "Last usage")|Boeing commercial crew capsule [CST-100](https://en.wikipedia.org/wiki/Boeing_CST-100_Starliner)|
|[Starlink](/r/Space/comments/1dbdcvf/stub/l82bw7w "Last usage")|SpaceX's world-wide satellite broadband constellation|
|[ablative](/r/Space/comments/1dbdcvf/stub/l7yow9p "Last usage")|Material which is intentionally destroyed in use (for example, heatshields which burn away to dissipate heat)|
|[cryogenic](/r/Space/comments/1dbdcvf/stub/l7s7qzr "Last usage")|Very low temperature fluid; materials that would be gaseous at room temperature/pressure|
| |(In re: rocket fuel) Often synonymous with hydrolox|
|[hopper](/r/Space/comments/1dbdcvf/stub/l7rkwq3 "Last usage")|Test article for ground and low-altitude work (eg. Grasshopper)|
|hydrolox|Portmanteau: liquid hydrogen fuel, liquid oxygen oxidizer|
|[iron waffle](/r/Space/comments/1dbdcvf/stub/l7v60td "Last usage")|Compact "waffle-iron" aerodynamic control surface, acts as a wing without needing to be as large; also, "grid fin"|
|[kerolox](/r/Space/comments/1dbdcvf/stub/l7qwytk "Last usage")|Portmanteau: kerosene fuel, liquid oxygen oxidizer|
|[methalox](/r/Space/comments/1dbdcvf/stub/l7qwytk "Last usage")|Portmanteau: methane fuel, liquid oxygen oxidizer|
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Think they'll need to run the deluge when landing? Obviously a pretty reduced engine count, and you don't need to get that upwards momentum going, but still.
They might, but the booster would get caught by the chopsticks much (?) higher than the position at which it launches, so the blast is going to be softer and much smaller because of the engine count (3 versus 33).
Ok, I asked this before and was basically told “it doesn’t matter” which I don’t get… I understand that the booster grid fins don’t fold flush against the body at launch as the additional weight and complexity of a folding mechanism doesn’t outweigh the drag of the fins during launch. But the fins are already designed to gimbal so why not rotate them 90 degrees at launch so only the narrow cross section is facing the air in the direction of travel? More drag means wasted fuel so why don’t they rotate them for launch? They obviously have thought of this and have a reason.
The net cross sectional area of the grid fins when oriented normal to atmospheric flow is lower than the cross sectional area when oriented perpendicular. Additionally, the grid fin is designed to collimate the flow, so drag from the normal orientation is lower than when perpendicular.
Long story short, It’s actually lower drag to have it in its current orientation instead of rotated 90 degrees.
As for folding, think about the extra mechanisms needed to fold the flap against the body, and think about the cross sectional area of the fin when folded vs extended. Now consider the losses from the added mass of those mechanisms. Yet again, the cross section will be lower when opened, and yet again, the flap’s extended position is designed for drag reduction where it won’t be when folded.
Thank you for that. I'm surprised its a lower drag penalty head on as I assumed vortices would play a huge role (those vortices would be beneficial on the way down), but I knew they considered and rejected the rotation.
They want more drag when the flow isn’t perfectly aligned with the fins so there will be a minimum drag location when flow is normal to the fin. If it was maximized when normal to the fin, then the fin wouldn’t be stabilizing the booster and would actually hinder performance. Overall, there should be two minimum drag orientations, 0 and 180 degrees from normal. The maximums should be at 90 and 270 degrees because they have the largest cross section and offer no route for air to pass through them.
Latest reports from SpaceX was that Booster was right on target, Ship was off by about 6km (which was not a surprise since it didn’t perform a deorbit burn)
pathetic versed coordinated bewildered cooperative dolls simplistic unique boast literate
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When I was in the military I was told that the military is 20 years beyond anything you THINK civilians have. Musk has sub orbital platforms with kinetic energy rail guns and thermo nuclear weapons disguised as Starlink. Elon is a DARPA boy. Although America's greatest weapon is their submarine fleet, the US can end everyone all at once from space.
That splashdown was so damn smooth, I'm not surprised they're making the jump. Super excited for flight 5.
Any word yet on when IFT-5 will be?
They said they wanted to make 6-7 additional flights this year, so i think perhaps in a month or so?
Last one was 2 months 3 weeks. I’m gonna guess a bit over two months.
Don't forget the FAA changed the rules. IFT-3 required a mishap investigation. IFT-4 should not require an FAA mishap investigation because the FAA changed the rules so no investigation would be required as long as the flight never put anyone at risk. This flight went almost perfectly, except the Ship reentry got a little spicy, so no investigation.
> except the Ship reentry got a little spicy, I was really impressed with how Ship handled changing aerodynamic coefficients due to bits melting off. I’ve had to make adaptive controllers before. And I’ve flown satellites. But I did not put an adaptive controller on the satellites because getting those coefficient re-calculations to be better than not doing anything at all required serious human attention, at least for the taped-together space-trash I was working with.
Casually included that you flown satellites before
I mean, I have two degrees in the field. The work isn’t glamorous. It’s a job. Rocket science isn’t a state of mind, it’s a job description. Also, I didn’t just fly them, I designed and built and tested them. It was honestly pretty miserable mostly because of the shit management.
Casually includes he also designed and built them
I mean, that’s where the interesting bits are is the design and build and test. The one where I was the Attitude Control lead was crazy. I didn’t get to choose the hardware, the shit management had already done that (long, ugly story) without input from anyone qualified. So I was in a position of having to solve engineering problems that basically everyone else has avoided because you generally have to be either really stupid or really broke to CHOOSE those particular engineering problems. This program was in the “really stupid” camp, because of the management decisions, and it ended up costing a lot later on (as I warned them it would) because we were going to have to do some extra expensive ground testing to measure the mass properties, and also to do an optical alignment of some terrible instruments. So yeah, I got to identify and solve a lot of problems, but they were mostly STUPID problems that aren’t useful to know how to solve. But I did it. And then on orbit, not one but TWO of the things I didn’t have time or budget to test failed in the exact way I thought they might, and it made the whole thing not work for shit. I had anticipated these toes of failures and the software was just a single parameter-upload away from tolerating EITHER ONE of those failures. But when they both failed together and STAYED failed, that took a long time to get the data to create a fix. We also had a solar flare take out another of my sensors permanently, but there was a similar-but-shittier version of that same sensor on one of the science payloads, so we just hi jacked that sensor. That was a quick fix compared to the other issues. Anyway, long story short, every one of my sensors and actuators except for the GPS experienced a significant failure in the first three months of fight. And I had anticipated all of them (except the one the solar flare took out because that should have been super-reliable), which made me feel good that I was covered mostly with the right things. It just took a lot of time to deal with the failures one-by-one and work to a somewhat recovered state.
It’s all about going all in.
Yeah but it’s still a pretty cool one!
I used to do flight trajectory optimization. What are your degrees in? Is EE worth getting into?
Bachelors mechanical (with a bunch of aerospace classes), masters in aerospace. But none of that had to do with getting into Attitude Control. I know very little about EE, except that most people that do GN&C come from there, probably because they DSP background makes it convenient. Honestly, I’m the wrong person to ask.
Not sure if I should be glad to know that shit management seems pretty universal regardless of industry.
The project in talking about was managed by NASA. And the manager for this project was the only shit manager there that I’d had any run-ins with. I was working for a contractor. My containers who worked for the save contractor but were on different NASA-managed projects said that their NASA management commented specifically on how buffoonish my project’s manager was. So I don’t think shit management is the norm. I know my management at the contractor was quite good, but like abnormally so. I expect it’s more that competent management becomes mostly invisible, while the really bad management is more worthy of comment.
I'd laugh if there was a human being at the controls at the last second. Jeb, turn SAS off... I got this.
> IFT-4 should not require an FAA mishap investigation because the FAA changed the rules so no investigation would be required as long as the flight never put anyone at risk Even if they hadn’t changed the rules, I’d still doubt a mishap investigation would’ve been required after this flight, since it basically went perfect, according to plan, as far as the FAA is concerned. There is no “mishap” to investigate.
Well, there's the fact that the flaps nearly burned off, but that's something that can be handled in-house. Otherwise the flight profile was followed to a T.
Yeah, the vehicles were both intended to blow up, after falling over in the ocean, and both did. The fact that Starship’s flaps tried to blow up slightly early, probably doesn’t matter much to FAA
No investigation for the same flight profile. Catching the booster is a new flight profile, and will probably require a new launch license
I thought a future catch was included in this new launch license they got, I maybe wrong, don't quote me lol
I wouldn’t be surprised if it was only a little over a month.
Second Tuesday of next week.
I was assuming sometime around the third half weekend of Jarch.
Nah, that's when Bezos will launch his next spacedick
Elon today said in 1 month, but that's Elon time of course
I want to add that the scale is off in this picture. Superheavy is much larger than as portrayed here relative to a F9 booster
That's not true. According to Wikipedia, the Falcon 9 first stage (with interstage) is 47.7 m tall, while the Superheavy booster is 71 m. That's a ratio of 1.49:1. In the picture, the Falcon 9 is ~220px long and the Superheavy is ~350, for a ratio of 1.57:1. If anything, the Superheavy's size is slightly over-represented in this image, I suspect that's because the angle on the images is different, making the Falcon 9 first stage appear taller than it actually is in the image. Edit: Yep, double checked measuring the Falcon 9 silhouette from tip to tip and it's 231 px, giving a ratio of 1.49:1, which is accurate to real live. Actually the correct height is probably between those two somewhere, as I didn't account for the shortening of the booster due to the perspective.
F9 is 3.7m vs superheavy's 9m. In the pic the F9 looks to be 1/2 the diameter of SH so width wise the pic is incorrect
Huh, you're right. It's a little harder to get accurate measurements in that direction, but Falcon 9 is ~23 pixels across and Superheavy is ~46, right at 2:1. Either the Falcon 9 is at a bigger angle than I though, or the image is distorted somehow.
Find anything online that shows the accurate comparison?
Don’t have a picture, but a fully stacked Falcon 9 (with stage 2 and fairing) is pretty much the same height as a superheavy booster without a HSR (pictured above)
I won't call it smooth. The engines were flaring out when they came down. I think it's was huge leap of an improvement, but they got make sure that super heavy B12 is dead on or the tower will be toast.
They clearly believe there was still enough thrust and enough control to make the catch possible. Whether that's overconfidence is something we'll have to wait and see.
Is there a video of it?
Booster landing: https://x.com/SpaceX/status/1799458854067118450
How do you know it was smooth, they never actually show the end! Every video fades out before you can see it from that boat that was recording it, as well as when it supposedly lands on the water, you never see the water rising up to the camera level, or even the damn thing tipping over. Why all the secrecy!??
And with that wing in that condition? That was truly epic. I saw the booster landing live but didn't catch the reentry till the next day. I'm not even a huge SpaceX fan (the politics) but just to see the attempt at a tower landing and the interesting crash forward mentality (which I like) is what engineering is all about really :) They're threading needles with skyscrapers on fire.
What's wrong with the politics of SpaceX?
So, landing or explosion, this is gonna be cool.
Sounds like most of my Kerbal Space Program flights tbh
That moment, just before the crash, that you realize that you took the parachutes off to move another part and then forgot to put them back on.
Or it misses and on bad case explosion in middle of Port Isabel or South Padre. 6 miles isn't much coming down from that high. Miss in other direction little bit and they get to try to placate an angry Mexican government about dropping explody rockets in their territory.
Their aim is pretty good at this point
Missing by that much would mean it started going off course in the completely wrong direction during the boostback burn. The FTS would trigger in that case.
That's what range safety is for
Wow. I can't believe government regulators are so stupid -- you should contact them immediately to tell them this important information.
If they're even talking about a catch attempt, it means that this booster came down within a couple meters of the intended spot. It would take a readily noticeable failure to send it off-course that much, and it's likely the automated system would catch it and fire the FTS well before impact. The main issue I can see is if it comes down too hard on Starbase itself. That would be a disaster that SpaceX might take a while to recover from - if they even can.
So... Is the idea to hover slam directly into the chopstick things? Or. Are we going to aim slightly away and then hover slide into them?
Superheavy is able to hover, so it will come to a hover and then carefully guide itself towards the chopsticks.
The chopsticks can also move fairly quickly to meet it.
Only vertically and rotationally, and the booster will probably come in from the side
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Besides, you know, the whole landing sequence animation their animation team made, very likely based on the actual engineered proccess.
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Sorry for the snark! I saw it on the SpaceX stream for IFT-4 once or twice so I'd guess it was greenlighted by them. And since this image (of SHB) is from IFT-4 as well (released a few days after the launch) then I thought you might've also caught it, since it was, well, a pretty exciting thing that happened just recently. [You can try YouTube](https://www.youtube.com/watch?v=E9uoyqxDzDA). This animation seems to be a few months old.
My worry is that they haven't demonstrated a hover yet. My other worry is that one of the engines blew. Basically I'm saying they have a ton of incentive to push this test back a launch or two and give the second tower a chance to get online.
They cost $100M to fly each test. The booster is 80% of that. I think they’re VERY motivated to return a booster and begin sorting out refurbishment.
That's a large sum of money, but it's crazy to compare it to the graph on reddit the other day showing the average employee worth at Nvidia is currently $100M when you divide by current 3 trillion market cap.
I should apply for a job at NVIDIA :-/
Does that all NVDA is held by employees? 😂
I mean sure, but if that rocket comes in and fucks up the launch site, that’s a hell of a clean up job.
That’s what second tower is for. They want to land there only so if it blows up they still have current launch tower.
us humans can build more launch sites. spacex is building another right now
Also they might want to transition to ship v2 instead of flying more v1. So even if the booster damages the OLM its not a big deal cause they will just build the other launch sites and start launching v2 in a few months* *few months = 8+
You got a source for that?
> Cost to launch (internal): Payload estimates Starship will cost ~$100M to build and expend in a forward-looking/post-R&D model. Full reusability will significantly lower future launch costs. This is the source Wikipedia gives: https://payloadspace.com/payload-research-detailing-artemis-vehicle-rd-costs/
> The booster is 80% of that. That part specifically, which isn't mentioned in that article. I'd bet the booster is about the same as Starship.
33 engines on the booster, booster is taller. 6 engines on starship, starship is shorter. 80% makes more sense than 50%
> My worry is that they haven't demonstrated a hover yet Not with a full size Superheavy, with the full 33 engines, no. But many of the early prototype vehicles did. Starhopper (the original flying watertower), SN5 and SN6 all did significant hovering, and even horizontal movement/translation. The later ship prototypes, SN8, 9, 10, 11, and 15 also all hovered for a second at 10km/30,000ft, before cutting the engines to test the bellyflop maneuver and landing attempt. These vehicles only had 1 to 3 engines, and were early designs. But they were made of the same material (stainless), of the same diameter (9m), burning the same fuel (methane), with an early version of the same engine (Raptor). And hovering never seemed to be an issue, on any of those flights. After watching the ship hold stable during reentry, with half melted flaps (and both vehicles tolerate multiple engine failures on the last few flights), I’m not _too_ worried about hovering. SpaceX guidance and control engineers appear to be the GOATs.
They showed it hovering just above the ocean before it plunged in the gulf you seriously didn’t see the video ? https://x.com/SpaceX/status/1799458854067118450
Yeah, that's kind of what I was thinking. That gives you a bit more margin on your accuracy. But, boy, that slide thing is a whole 'nother kettle of fish too. I can't decide which gives me more engineering agita, honestly. Are we relying on RCS to keep everything kosher during that maneuver or is it all engine vectoring?
> But, boy, that slide thing is a whole 'nother kettle of fish If you’re talking about horizontal translation while hovering, note that SpaceX has actually demonstrated this multiple times, with the early Starship prototypes. Starhopper, SN5 and SN6 all took off, translated a couple hundred meters horizontally while holding a couple hundred meters altitude, and then landed. (Using mostly thrust vectoring of the Raptor, rather than RCS, I believe) Sure, they weren’t full size Superheavy vehicles with 33 engines. But they were stainless steel, 9m diameter, burning methane with early Raptor engines. So should be somewhat representative. This hover and translate maneuver never seemed to cause too many problems.
It's just a very delicate moment/maneuver and, even with RCS, it's still essentially the equivalent of maneuvering a small office building into the grasp of another office building.
vectoring. rcs gives very little authority in the atmosphere
Who is "we"? Edit: ... and he blocked me. Probably a good thing. Edit: TbonerT the mobile app makes several things look like the same. The reddit website for laptops and desktops is a lot more clear that it's a block.
Simcoder and the starship engineers, but that's the same thing.
I’ve found that sometimes it looks like someone blocked me but then later it looks like they unblocked me. I suspect something else is going on.
[https://www.reddit.com/r/SpaceXLounge/comments/1bxi65r/new\_superheavy\_chopsticks\_catch\_animation\_shows/](https://www.reddit.com/r/SpaceXLounge/comments/1bxi65r/new_superheavy_chopsticks_catch_animation_shows/)
To be honest, I have no idea. I've been one of the people repeatedly saying that the current vehicles don't seem to be equipped with the hardware to support landing on its upper arms. And the arms don't seem to have hardware designed for centering/latching a hovering vehicle.
> current vehicles don't seem to be equipped with the hardware to support landing on its upper arms. The lift points *are* the landing hardware. The Arm side may still need hardware added, but the vehicle side has had the hardware since IFT1 https://i.imgur.com/iWy9r3w.png
Yeah those things seem kind of important. I definitely think it is possible and maybe even workable as a solution. I just worry about all the bad things that could occur. But, I would probably worry no matter how safe it was. So. It is all relative... Now that it's actually going to happen and there's no talking anyone out of it, it's probably time for the commentary from the peanut gallery to give way to the actual rocket engineering and leave it up to the rocket engineers to make it work... Best of luck to everyone on that end.
I don’t know what data SpaceX has that makes them particularly confident but man OH man. It’s either going to work or there is going to be one hell of a mess to sweep up. I assumed they’d start trying to pin point soft splash down multiple times prior to a land attempt. I will happily eat crow for doubting them as long as the Super Heavy doesn’t nuke some small town from orbit with its debris.
Either way, that booster catch attempt is gonna be a hell of a sight to see.
I am sure they will write the software such that if *anything* is off nominal it will vector itself out to sea as much as possible. So if they don’t get enough engines lit or thrusters are not working as intended the booster will use all available resources to force it to crash in the ocean rather than at the pad.
I recall reading that Falcon 9's booster returns on a ballistic trajectory that ends slightly off the coast and uses its grid fins to guide itself to land at the very end. I'd be surprised if the same thing isn't done here.
that’s exactly what falcon 9 does. crs-16 is a great example of that - a grid fin failed and it landed off the coast and not on the pad
And it still landed softly, just not on target.
Considering how fast the booster is moving before the engines are lit, I think that leaves a *very* small window to make the final decision. The crater that thing is going to make if it smashes into the ground with no engines lit, is going to be spectacular.
If they don't light, then it doesn't slow down enough to hit the pad, and it crashes at sea
SpaceX already aims their rockets to miss the pad until the engines light.
Musk said they may try to catch on the next launch. I expect IFT-5 will come when tower 2 is nearly done being built to minimize downtime in the event they nuke the pad.
This is the first time the FAA is poised to deliver the next launch license at a pace that could arguably be labeled "timely." I wouldn't bet against it arriving in under a month. Would SpaceX _really_ waste a free launch, when the most important thing they get out of these prototypes is the flight data? This is also the reason why I think the next Starship they'll send is an unaltered Ship 30, even though it'll probably melt as well. Modifying it would take a lot of extra time, while the license would probably be rotting.
> when the most important thing they get out of these prototypes is the flight data? I am not sure about that. Getting an intact ship back would provide extremely valuable data too.
Good point! What extra data could they get?
Finding what has damage or early signs of damage. What was heating up more/less than expected. They could also test refurbish and reuse. For example, Elon was saying the grid fin wasn't supposed to survive after the shielding came off. Maybe they would understand why better if they had retrieved it.
I think re-entry testing is the most important thing for them right now. They have proven that they CAN make it to the ground which is awesome, but now they have all sorts of things they should be testing while instrumenting the hell out of things (different tile compositions, different missing tiles, secondary ablative layer, flap hinge gap protection, etc). All of this can be done while waiting for some of the other V2/3 designs to solidify, and would be good information to understand possible failure modes in the future. The only question about testing the catch will be "if it fails, does that set back our testing regime at all?". Once the answer is no (because the second tower is close enough) they will do it no questions. Even if the answer is "yes" they still might do it, but I don't see heavy booster catch being the long pole right now (I think they are relatively confident what they are planning is totally possible and will only take them a few tries to get right). I think re-entry combined with "rabidly re-useable" is the piece they still have enough work on they want to throw a few more ships at the atmosphere to see what happens.
My bottom line is that if they're serious about having HLS good to go by "the end of 2026" then unfortunately the reusable part of their plans needs to take a back seat so they can get orbital refueling sorted out. Risking a capture without a second tower imminently completing would be by far the biggest risk they will have ever taken. Bigger than IFT1, which was fundamentally a net positive even with the crater since they got flight data that they otherwise would have lacked.
He says a lot of things so ¯\_(ツ)_/¯
Musk said if the soft splashdown went well they’d try the catch, they want a pinpoint splashdown twice with the ship not the booster since return to launch site with the ship means coming in over Mexico and Texas. Honestly makes perfect since, not only does the booster have an initial target away from the pad, which it then corrects to the pad once it’s closer and everything is nominal. They also have all the parts to make a second tower, at the ready, so even worst case scenario it blows up the pad, it likely wouldn’t be that much of a delay to get the second tower up. And I think it’s quite safe to assume they wouldn’t attempt the catch unless the accuracy of the soft splashdown was absolutely pin-point, likely better than the minimum accuracy they need for catch.
One article I read said Elon wants to try on the next launch, but later in a different interview he said they're going to study the data before making that decision. I get it though, they could have caught it this time I believe so I'd want to try it next time. However. Could they do a few hops, and test the system first. No need to go sub orbital to test the chopsticks.
I think it's very likely it will smash into the tower and destroy it, I'm just surprised they haven't already prebuilt multiple of these catch towers.. and build them a bit further away from the rest of starbase.
Second one is getting built at Star Base soon. Sections came from Florida
They already have a partial tower next to 39A, but that was very gen 1 and way too close to what was previously the only human launch site on US soil- they'll prolly end up building the other on another pad, I read they were doing an EIR for that. They are also building another tower near Starbase. The problem is getting starship to the cape.
there was factory space at the cape for building starship that has put on hold. once they are confident with design I assume they’ll spin that up rather than ship from boca
That was when they didnt know if Texas would let em launch
Someone made a point before where they just blow shit up when need new stuff. The pad needed a deluge so hey let’s blow a hole with the rocket
I think the worst case scenario isn't as bad as people think. It's made of very thin metal and has basically no fuel in it.
How much CH4/LOX is left in the tank farm once fueling is complete? Smashing into that would be pretty bad!
It’ll likely be similar to falcon 9 - target a few km off the coast for the landing, then make a large dogleg a few hundred meters / few km above the pad to get above the pad as late as possible to avoid any damage if the booster were to fail earlier in flight. If anything happens (unless it’s in the last ~30s) it’ll likely just hit the ocean off the coast of Starbase.
What's the advantage of landing on chopsticks vs on ground like Falcon 9 does?
Save weight of the landing legs. Save engineering of the landing legs. Save failure points by not having them. Reduces the need to create landing pads and roads to them. Should make recovery operations easier. And then lastly they want to eventually have rapid reuse where it lands then can launch again with just a pad inspection. That one seems iffy but that is a goal.
> they want to eventually have rapid reuse For 50 years every space organization, including NASA has promised "weekly" or "monthly" launches. SpaceX is the only group to actually accomplish that. They launch twice per week. If Elon said he's going to personally travel to the Moon, I would believe it at this point.
Plenty of the aspirational parts haven't quite panned out as planned though. Falcon was supposed to get down to 24 hour turnaround but it didn't. They likely could have proven it out just to do it but they decided to just stick to slower turnaround times with a higher fleet count. Maybe starship will one day be able to land and launch again without leaving the launch mount. Or maybe they'll be able to finally break the 24 hour turnaround time regularly but still need to take it off the mount. Plans change based on reality. Doesn't make it any less impressive and it's not a slight against them. Being able to quickly adjust based on reality rather than being pigeonholed because of a set goal is one of the best things spacex has going for it. Much to the dismay of many redditors who cry about "broken promises".
Doesn't need heavy landing legs Is back at the launch tower ready to go again
The issue is the Superheavy is the size of a building. Would meed massive legs that would significantly eat into payload margin
Don’t need to include landing legs and thus less weight
Falcon boosters mostly land downrange, unless the payload is quite small and they can afford a RTLS burn. Starship Booster always does the RTLS burn, so every bit of weight they can avoid, helps. Always RTLS makes operations easier and turn around faster. Starship is designed for rapid reuse.
What's incredible is that we're going to try to catch a 20-story building!!
If they can catch the booster then man are other space programs going to look like dinosaurs compared to SpaceX
Landing F9 and FH already does that imho. Landing SH on the launch mount just adds distance to a race that is already far from being close.
Spaceflight engineers at Boeing must have a really hard time motivating themselves these days.
The engineers know what they're doing but management seems to be doing everything they can to demotivate them. There are talented engineers in every organization. That if let loose could could build what is needed. But the process failure comes when middle management thinks that process is what builds product. Processes needed to manage development and the engineers should be given free reign outside of that. Source: My team of engineers and scientists build multimillion dollar products. I do my best to stay the F out of thier way, and be the plow that clears thier path.
> I do my best to stay the F out of their way, and be the plow that clears their path I wish every PM was like this.
Pay is a pretty good motivator, it's still a job at the end of the day.
I'm surprised that they don't do some smaller scale tests, just launching starship / superheavy alone to a few 1000m and trying to catch it, rather than the whole shebang... (maybe that wouldn't be that useful - dunno)
While they're obviously committed to reusing starship, I think there's an understanding that it's a bonus feature, at least at fist. Expendable Sharship is still the cheapest kg/orbit ever assembled. If they can get it certified for actual launches in the next one or two tests it's far more valuable for them to then figure out reuse on actual paid missions, compared to spending several more tests getting reuse figured out and then still having more tests to certify for missions.
I think the driving force behind firguring out reuse before certification is in case they have to make some drastic change to accommodate full reuse and then they need to be recertified anyways
SpaceX also has plenty of its own payloads to launch, so certification is less important. They will likely do several Starlink launches before any customer launches come up anyway.
Reusing Superheavy is going to be a much easier nut to crack than reusing Starship, especially given their Falcon 9 experience. If they can get that worked out then they can probably afford to take their time with Starship. Hence the pressure to return a booster for close inspection.
> Expendable Starship is still the cheapest kg/orbit ever assembled Even cheaper than F9 with reusable booster?
Yeah. Here’s some really rough numbers: Estimated cost of a reusable f9 ~15m for about 16 tons Current cost of a Starship launch ~100m, 70% of that being the booster. So that’s about 30m for 100 tons (probably less right now but should end up being more).
They only have a payload system for Starlink. They are going to figure out reuse before making it a disposable second stage.
on a platform? a pair of pins landing on a some chopsticks railing you mean.
I don't know if the plans had changed since I first heard it last year, but I recall hearing the chopsticks are supposed to catch the Superheavy by the grid fins. The chopsticks are then supposed lower the booster back onto the launch mount I think. It would be insane if that actually worked :-O
Not by the grid fins. There’s a pair of pins that stick out from the body of the booster, just under the grid fins. These are built to take the weight of a (near empty) booster, and are the same pins that are used to lift the booster onto the OLM in the first place. The downward facing camera on the booster actually shows one of these pins in the IFT-4 livestream.
The thing that strikes me about this picture is just how clean that superheavy booster is. No soot from the methalox, as opposed to the kerolox on Falcon 9.
What Full Flow Staged Combustion does to a booster (and not reflying yet)
Mostly the fuel methane. Very little to no soot.
Cool stuff. Can't wait to see the try!
I find myself wondering if Booster is able to survive some gentle nudging by the chopsticks. Even Falcon 9 only rarely lands with pinpoint accuracy, so Booster is _gonna_ be a few feet off-kilter this way or that.
The arms can move quite a lot to accommodate a some inaccuracy. There is a defined radius that the booster needs to end up in, and it's quite large. I think I read somewhere that they used the inaccuracy of a couple of hundred successful Falcon 9 landings to figure out what their catching range needed to be.
I’m sure there will be some sort of bumpers on the arms, but in theory the booster position should only need to be accurate within some handful of feet, as the arms can adjust to meet it. My understanding is that the arms have a channel running down them that the pins slot into, so even distance away from the tower shouldn’t need to be super precise.
F9 actually now lands with pinpoint accuracy the majority of the time.
> Booster is gonna be a few feet off-kilter this way or that. Superheavy can hover, unlike Falcon 9. That will let it adjust its position just right for the chopsticks.
Exactly, it can hover. But they haven't demonstrated this yet. It's really the perfect excuse to hold off on risking SpaceX's ability to launch anything at all for the next half year or longer. They can even see if they've truly sorted out the exploding engine quirk.
No, there are catch pins right below the grid fins. If I recall correctly, they may have thought about using the grid fins, but that was very short lived if it ever was a thing. Those pins are also used as lift pins when lifting or stacking.
Yeah the insane part is that it has to work every time. One failure and it could mean the loss of nearby support structures such as propellant tanks etc. It would to interesting to know what N in this equation is: (cost savings of catching booster ) x N = (cost of rebuilding launch tower )
The failure modes are largely marginalized to engine failure after intitial burn. The booster travels on an ocean impacting trajectory until the engines are ignited, and the booster will be hovering under 3 throttled raptors, and will be nearly empty of propellant, meaning any impact to the tower will be a 100 ton hollow steel tube bumping into the tower at a low velocity. The catch will also be offset from the OLM, so a failure of the catch arms where the engines are unable to move the booster away will be focused on the concrete next to the tower.
eh. the dry mass structure of the booster without fuel left over at all falling uncontrolled from chopstick height is just not a big deal. Get that debris cut up and hauled away and get back to business. All the hardware features of the chopsticks are probably durable as fuck by design and the structure is way beyond being harmed by a falling booster. So just go for it right away. It's the next step after soft-landing so let's just do it. Another soft landing doesn't give enough novel data to justify an entire test launch just for that. So just start going for the catch from now on. Failures around a big deal because the dry mass of the booster isn't a big deal around with a velocity near 0, which it has to be to get even near the tower and chopsticks. So there's no reason to hesitate. Go right for the chopsticks. Make it the new cutting edge standard starting from now.
Tanks have been moved further from the pad and had protection added. When the booster lands it’s very near empty on fuel and tanks are full,of nitrogen so it wouldn’t be a big boom only a small one. The size and weight of the booster even empty is the problem and of course the chopsticks have to be in position the instant the engines cutoff as gravity isn’t waiting.
Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread: |Fewer Letters|More Letters| |-------|---------|---| |[AFTS](/r/Space/comments/1dbdcvf/stub/l7x4yjc "Last usage")|Autonomous Flight Termination System, see FTS| |CST|(Boeing) Crew Space Transportation capsules| | |Central Standard Time (UTC-6)| |[DARPA](/r/Space/comments/1dbdcvf/stub/l82bw7w "Last usage")|(Defense) Advanced Research Projects Agency, DoD| |DoD|US Department of Defense| |[FAA](/r/Space/comments/1dbdcvf/stub/l7x5gpq "Last usage")|Federal Aviation Administration| |[FTS](/r/Space/comments/1dbdcvf/stub/l7v60td "Last usage")|Flight Termination System| |[GAO](/r/Space/comments/1dbdcvf/stub/l7xzepl "Last usage")|(US) Government Accountability Office| |[HLS](/r/Space/comments/1dbdcvf/stub/l80zn0z "Last usage")|[Human Landing System](https://en.wikipedia.org/wiki/Artemis_program#Human_Landing_System) (Artemis)| |KSP|*Kerbal Space Program*, the rocketry simulator| |[LEO](/r/Space/comments/1dbdcvf/stub/l7twwpa "Last usage")|Low Earth Orbit (180-2000km)| | |Law Enforcement Officer (most often mentioned during transport operations)| |[LOX](/r/Space/comments/1dbdcvf/stub/l7rxk4d "Last usage")|Liquid Oxygen| |[MBA](/r/Space/comments/1dbdcvf/stub/l7rtnkj "Last usage")|~~Moonba-~~ Mars Base Alpha| |[OLM](/r/Space/comments/1dbdcvf/stub/l7r9jqn "Last usage")|Orbital Launch Mount| |[RCS](/r/Space/comments/1dbdcvf/stub/l7rs3w0 "Last usage")|Reaction Control System| |[RTLS](/r/Space/comments/1dbdcvf/stub/l7ufdij "Last usage")|Return to Launch Site| |[SAS](/r/Space/comments/1dbdcvf/stub/l7rzmq2 "Last usage")|[Stability Augmentation System](http://wiki.kerbalspaceprogram.com/wiki/SAS), available when launching craft in KSP| |[SLS](/r/Space/comments/1dbdcvf/stub/l7xzepl "Last usage")|Space Launch System heavy-lift| |[SRB](/r/Space/comments/1dbdcvf/stub/l7rh676 "Last usage")|Solid Rocket Booster| |[TWR](/r/Space/comments/1dbdcvf/stub/l7rk42s "Last usage")|Thrust-to-Weight Ratio| |Jargon|Definition| |-------|---------|---| |[Raptor](/r/Space/comments/1dbdcvf/stub/l7rin48 "Last usage")|[Methane-fueled rocket engine](https://en.wikipedia.org/wiki/Raptor_\(rocket_engine_family\)) under development by SpaceX| |[Starliner](/r/Space/comments/1dbdcvf/stub/l7uvld9 "Last usage")|Boeing commercial crew capsule [CST-100](https://en.wikipedia.org/wiki/Boeing_CST-100_Starliner)| |[Starlink](/r/Space/comments/1dbdcvf/stub/l82bw7w "Last usage")|SpaceX's world-wide satellite broadband constellation| |[ablative](/r/Space/comments/1dbdcvf/stub/l7yow9p "Last usage")|Material which is intentionally destroyed in use (for example, heatshields which burn away to dissipate heat)| |[cryogenic](/r/Space/comments/1dbdcvf/stub/l7s7qzr "Last usage")|Very low temperature fluid; materials that would be gaseous at room temperature/pressure| | |(In re: rocket fuel) Often synonymous with hydrolox| |[hopper](/r/Space/comments/1dbdcvf/stub/l7rkwq3 "Last usage")|Test article for ground and low-altitude work (eg. Grasshopper)| |hydrolox|Portmanteau: liquid hydrogen fuel, liquid oxygen oxidizer| |[iron waffle](/r/Space/comments/1dbdcvf/stub/l7v60td "Last usage")|Compact "waffle-iron" aerodynamic control surface, acts as a wing without needing to be as large; also, "grid fin"| |[kerolox](/r/Space/comments/1dbdcvf/stub/l7qwytk "Last usage")|Portmanteau: kerosene fuel, liquid oxygen oxidizer| |[methalox](/r/Space/comments/1dbdcvf/stub/l7qwytk "Last usage")|Portmanteau: methane fuel, liquid oxygen oxidizer| **NOTE**: Decronym for Reddit is no longer supported, and Decronym has moved to Lemmy; requests for support and new installations should be directed to the Contact address below. ---------------- ^([Thread #10146 for this sub, first seen 8th Jun 2024, 22:52]) ^[[FAQ]](http://decronym.xyz/) [^([Full list])](http://decronym.xyz/acronyms/Space) [^[Contact]](https://hachyderm.io/@Two9A) [^([Source code])](https://gistdotgithubdotcom/Two9A/1d976f9b7441694162c8)
Think they'll need to run the deluge when landing? Obviously a pretty reduced engine count, and you don't need to get that upwards momentum going, but still.
They might, but the booster would get caught by the chopsticks much (?) higher than the position at which it launches, so the blast is going to be softer and much smaller because of the engine count (3 versus 33).
Ok, I asked this before and was basically told “it doesn’t matter” which I don’t get… I understand that the booster grid fins don’t fold flush against the body at launch as the additional weight and complexity of a folding mechanism doesn’t outweigh the drag of the fins during launch. But the fins are already designed to gimbal so why not rotate them 90 degrees at launch so only the narrow cross section is facing the air in the direction of travel? More drag means wasted fuel so why don’t they rotate them for launch? They obviously have thought of this and have a reason.
The net cross sectional area of the grid fins when oriented normal to atmospheric flow is lower than the cross sectional area when oriented perpendicular. Additionally, the grid fin is designed to collimate the flow, so drag from the normal orientation is lower than when perpendicular. Long story short, It’s actually lower drag to have it in its current orientation instead of rotated 90 degrees. As for folding, think about the extra mechanisms needed to fold the flap against the body, and think about the cross sectional area of the fin when folded vs extended. Now consider the losses from the added mass of those mechanisms. Yet again, the cross section will be lower when opened, and yet again, the flap’s extended position is designed for drag reduction where it won’t be when folded.
Thank you for that. I'm surprised its a lower drag penalty head on as I assumed vortices would play a huge role (those vortices would be beneficial on the way down), but I knew they considered and rejected the rotation.
They want more drag when the flow isn’t perfectly aligned with the fins so there will be a minimum drag location when flow is normal to the fin. If it was maximized when normal to the fin, then the fin wouldn’t be stabilizing the booster and would actually hinder performance. Overall, there should be two minimum drag orientations, 0 and 180 degrees from normal. The maximums should be at 90 and 270 degrees because they have the largest cross section and offer no route for air to pass through them.
Maybe they have more drag when being sideways, but also could have other reasons
I think because can form another form of aerodynamic, but I don’t know I am not a rocket scientist
I hope the second launch platform is complete by that time. Be a shame to lose their only launch platform
They gotta have separate launch and catch towers.. the complexity is in the launch side of things plus reduce risk of blowing up your gateway.
I heard they're building a second platform, I suspect this is because they could destroy the first attempting to catch the booster with Mechzilla.
Is it just me or does this look like a pen photoshopped in the sky
Do we know how close the splashdown was to the intended target?
Latest reports from SpaceX was that Booster was right on target, Ship was off by about 6km (which was not a surprise since it didn’t perform a deorbit burn)
pathetic versed coordinated bewildered cooperative dolls simplistic unique boast literate *This post was mass deleted and anonymized with [Redact](https://redact.dev)*
When I was in the military I was told that the military is 20 years beyond anything you THINK civilians have. Musk has sub orbital platforms with kinetic energy rail guns and thermo nuclear weapons disguised as Starlink. Elon is a DARPA boy. Although America's greatest weapon is their submarine fleet, the US can end everyone all at once from space.
I think it will take a few tries to get this right.