Starship Integrated Flight Test 3 Analysis
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- čas přidán 15. 03. 2024
- What happened to the IFT3 Starship?
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I completely agree with your point that the loss if the vehicle is what most aerospace companies expect so we should not criticize SpaceX for attempting hard things. This reminds me so much of what Kennedy said in his famous Moon Speech "We choose to ... do the other things, not because they are easy, but because they are hard ... because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one we intend to win..."
That's right. Setting our sights low does not make us great.
The Starship was spinning, before reentry!
It was indeed.
It looked to me like their fuel transfer test had created an unstable secondary axis of rotation. This would result in the creation of the " tennis racket effect. " The ship would be virtually uncontrollably on reentry.
no. what destabilized the orbit part of it was that the payload had a significant amount of atmospheric pressure when they opened the payload door. you can see the pressure rush out breaking the door and introducing an enormous amount of roll.
@@robertoler3795 True. But it appeared that any attempt to cancel the roll caused a tendency to tumble and vice-versa. czcams.com/video/1n-HMSCDYtM/video.htmlsi=IKUYsrIB8ozd6sAq
@@robertoler3795I just watched that section back of the launch and you may be right. The light coming through the payload door did start rotating around that time. Regardless, I dont think their method of using the vents as control thrusters worked that well/at all. Maybe not powerful enough? Maybe they'll have to take the weight penalty and use proper RCS.
That's a very good point...
Interesting... can you link on the SpaceX time?
3:48 I f'ing love your analysis videos, dude! I completely forgot the base of Starship is heavier than the nose.
Thank you so much!
One of my friends was questioning the frequent crashes and "failures" of the system, and was genuinely asking me to explain how this was progressing the Starship program. I gave him the same perspective that you point out in the video: If they only ever did as well as they did in IFT-3, they'd still be as good as any expendable launcher, but with MUCH greater payload capacity.
They could, in fact, start flying low-risk payloads like fuel for a depot or even Starlink satellites, and keep trying to recover the booster and ship as a bonus (much like they did for Falcon 9 boosters). That would also help push along development of Lunar Starship, since that relies on orbital refueling, and they could use the launch of the depot and the refueling flights as development flights for recovering both stages.
Many missions to space stations require return to earth. This is still in progress.
@@yurijmikhassiak7342 Yes, but my point was that they can perfect the reusability and upper stage return as we are flying payloads that don't require that, rather than simply launching the full stack with dummy payloads over and over until they resolve reusability issues.
I would agree James. It is a successful mass to orbit vehicle now. More capable than any on Earth. They just have grander goals.
An interim 3rd stage for Starship might be the way to go for Artemis. Starship can lift around 200 metric tons to LEO when both stages are expended. Starship's 200 tons to LEO plus a 9 meter diameter leaves plenty of room for an interim luna cargo 3rd stage. When Starship is human rated, SLS should be phased out. Starship could do it for less than 1/10th of SLS and still make a very nice profit. This would also allow time and missions to work on reusability and orbital refueling. Both of which make Starship a better long-term solution.
Let's face it, Artemis is a mess right now.
I agree
I am not going to conclude the Starship isn't stable in hyper sonic re-entry until I see if actually start enter in a proper orientation. I think it was doomed early on with that constant roll. At first I thought it was rolling to settle the fuel for propellant transfer, and maybe it was, but it should have stopped before entry. Also was the boosters control system in an oscillation when the landing burn was supposed to start? Sure looked like the grid fins were reacting way late and encouraging the osculations. So does this trigger a mishap investigation? Or are they good for another launch license?
Probably doing mishap investigations first; fixes made, try again
Definitely a mishap investigation as neither stage completed the planned landing.
Yes, this flight did trigger a mishap investigation. Whenever a test flight from any company does not go how it is laid out in the license, an investigation is automatically triggered. The only way one wouldn't have been triggered in this case would be super heavy making a softish splashdown after a mock landing burn and ship making it through reentry in one piece then belly flopping in the water as the license stated.
Yes anything that deviates from the planned flight plan automatically triggers an investigation. Over time as these new issues show themselves and get fixed fewer thigns should go wrong and so will eventually stop triggering investigations.
Many modern reentry vehicles would have righted themselves and survived...
Awesome video going into technical details, good work.
Glad you enjoyed it!
I'll be following your channel from now on. Very insightful!
Thank you very much Phillipe!
@@terranspaceacademy Subscribed.
Thank you adolf.
There’s a critical flaw in your assumption that the RCS thrusters weren’t adequate for reentry maneuvering - the ship’s orientation appeared to be incorrect for the coast phase of flight as well, and as far as I can tell, we saw ZERO maneuvering of any kind (minus some flap actuation.) I don’t think orientation maneuvers of any kind occurred.
So yeah, the hot gas thrusters may be inadequate, however I don’t think they even had a chance to check.
Also the body flap idea is interesting, however (as you said) it requires the correct orientation of the ship to serve its purpose and function correctly, requiring adequately strong thrusters to do so. Once you have such thrusters, the body flap then becomes redundant anyways.
Asymmetrical (top vs lower) flap deployment would easily be able to provide pitch authority. We saw this with ship tests. I see no reason for any sort of body flap. Plasma / hypersonic phase or not - if the body flap was functional on shuttle etc, so too would the flaps on starship.🤷🏻♂️
It's pretty obvious that something went awry with the RCS. The firing tapers off around 40 minutes on the mission clock.
I was impressed the flaps managed to nullify the roll as re-entry started, but looked to me like there was a pitch oscillation until the video feed was lost. The two ends of the ship took turns getting blasted with heat and shooting sparks everywhere then hanging in the plasma wake.
Loss of pressurization when the engines aren't running? We'll look at it today.
Outstanding information. You never disappoint!! I hope you can keep up the good work.
Thanks, will do Terry!
I think flight went Great - think tumble was caused by a leak - venting looked haphazard /random - took awhile for tumble to start after engine shutdown -
did not see any attitude thrusters fire maybe i missed seeing - flight was Exciting and video was Spectacular - Thanks
Engine blowout? It was indeed exciting though :-)
@@terranspaceacademyI think if it were engine blowout they wouldn’t have reported the spin as the reason they didn’t attempt the second burn
The super heavy booster uses the same attitude thrusters as the ship. It’s just as large and it performed admirably after the hot stage to stabilize the booster. I would not be surprised to learn that there was some type of malfunction, either with the system itself or otherwise.
A stuck valve is most likely...
I’ve been watching since 2020 and enjoy ad learn from each episode. Listening to your ask for support after this episode reminded me that if I want to keep learning from you, I should do my part to help make that possible. So I just joined your Patron support team. I would challenge others to ‘pay their way’ as I am now doing.
Keep teaching, you are very skilled in explaining space technology.
Ad Astra, Pro Terra!
Thank you so much Mike. I have dedicated a lot of time and your support is greatly appreciated to keep going. Ad Astra Pro Terra.
Another excellent reasoned and clearly explained analysis from Terran Soace Acadamy. Thank you
You are most welcome and thank you!
SpaceX is fighting the cost. SpaceX knows hypergolic thrusters are more powerful, but not good for RAPID reusability.
IFT-3 shows there is still a lot of work to do for a fully rapid reusable launch system. But, while they are chasing the 2nd stage reusability, they can soon start to launch Starlink satellites with the coming ITFs.
A huge congratulation to SpaceX for a new generation super heavy lifter, the future is super bright for them.
Very true. And having any hypergolics on board complicates things tremendously.
very informative and to the point. thank you
You are most welcome!
You are right, this was a very successful flight with progression from IFT 1 and IFT 2. SpaceX have been clear that their objective for this flight is to learn and then improve. "Completing" all of the flights' plan is a bonus and not the definition of success: progress is what they want.
It was 23 flights of Falcon 9 before SpaceX first successfully landed on a drone ship (the 20th flight was the first on land). Those prior flights included 9 tests at sea (not including the 2 parachute tests).
If SpaceX manage to land both booster and ship intact by the end of the year, that would be astonishing. But land both they will.
It's all in the perspective. I wish he would have put something in the cargo bay to go on to orbit :-)
I found your perspective. Interesting. I like the detail you put in to the explanation.
Thank you very much Christopher.
I like your delivery and flow of info. Very digestible lol. Thx!
You are most welcome.
Note: I am one of those who remembers the Vanguard and Jupiter flights. My dad as an apprentice tool and die maker made parts for Explorer one. I watched the Echo balloons floating by at night. Keep up the good work.
That is amazing! You must be very proud of him. And thank you.
Alright! This video is the reason I watch. I learned some things, thank you!
Glad it was helpful Paul!
As Always, very well done. didn't want that one to be over. lol
Thank you!
You may well be correct about the control of Starship during re-entry, but not this time. Starship was out of control long before re-entry, watching how it was spinning. Not sure when the spin started, but it was stable after meco.
Stronger RCS could fix that :-)
I generelly disagree. Assuming without any solid evidence that the thrusters are sized too small for this ship is just naiv. There are thousands of engineers working on this rocket, determination of the thrust output of the thrusters for given moments of inertia is a relatively easy thing. Ship was spinning in the whole coast phase and wasnt even lined up correctly BEFORE aerodynamics came into play and this would indicate the failure of thrusters due to icing for exmale or something like that
The shuttle had to use its OMS/RCS which was much stronger than Starship's system.
@@terranspaceacademy comparing apples with bananas. The question is you think that SpaceX didn't think of this all the way through? Obviously it's more than visually comparing them comparing specific impulses and then deciding by gut feeling " ah damn that thruster looks small in comparison, it has to be undersized! " That's bs.
I just think the RCS system wasnt functioning to begin with.
I agree about the thrusters size. Your video made me see the tons of fuel sloshing around inside the Ship, with the computer frantically adjusting winglets and firing thrusters to stop the spin and roll. The Ship needs wider rear wings to incorporate landing legs anyway. Enlarging the rear wings kills two birds with one stone.
There most likely wont be landing legs on boosters.
Should they put vertical stabilizers on the flaps :-)
I'm only 19 seconds in. Thank you for moving logo, had to stop last one because it was so large it blocked ship info.
Sorry about that... Trying out new buttons. Now I know what that one does :-)
Thank you for the detailed lesson. I wish we had more like you in this world. God bless you sir…
Thank you so much!
Ah, Much Appreciated!
You are most welcome Stefan!
The unstable last phase of the booster approach looked like they copy and pasted the PID values from a F9 booster and forgot to adjust for mass and length. I'm sure that's not what happened, but I like to armchair engineer LoL
That's what it seemed like with the early versions of the heavies
Hypersonics/transsonics/subsonics. Aerodynamics is sketchy in that case. You CAN'T model everything perfectly without testing. Aerodynamics models are not precise enough in that case. Especially when there is involved both rapid change in altitude, pressure and velocity. IFT3 was first test that could point witch simulation model was closest to reality.
NASA probably would test everything in scaled models in specialised air tunnel, but that kind of test facility is simply very expensive. SpaceX approach is just model everything in virtual, then confirm models in real tests. That approach is actually cheaper, as cost of ship is relatively cheap (under 100mln per launch). Especially that some things cannot be tested on the ground. Ie reigniting raptors against near subsonic airflow, ignition of engines in vacuum, plume expansion due to low pressure etc. All of those things can be approximated in theory, and then tested in real life. Ie re-entry profile of Orion capsule was tested by launching it on board of Ares I rocket.
So while indeed SpaceX chose wrong values for PID, it wasn't because someone "forget" something. It was because simulations showed that that was most probably profile. And it was wrong. But now with telemetry they can simulate way more accurate
It did look like they were not planning to control a spin on something that big.
@@terranspaceacademy I doubt. For me it looked like they cancelled spin control as RCS was over steering. Initially, I I recall ,both on RCS and aerodynamics booster turned left, then right... And again, again.
Compared that with ship spin, now I think it was algorithm issue. It simply wasn't able to deal with changing conditions of ullage-RCS. This kind of RCS will have variable thrust as it will be dependent on overpressure in tanks. If spaceX will soon make some tests on site with ullage thrusters that will confirm my theory
Just wanted to say your channel is incredibly informative you call it just like you see it you’re not biased for her against starship or Elon or anyone else for that matter. Wish you the best with growing your channel. It’s very appreciated. I’ll share with everybody. I know that might be interested.
Thank you so much!
Thank you for summing up a 2 hour live stream
You are most welcome!
Another great video and solid reentry design modifications/enhancement suggestions!…and I just joined your Patreon team😊
Thank you! We appreciate you!
@@terranspaceacademy , Appreciate you Sir!
+1 for stats. Thx for great content.
Thank you!
Okay I didn’t have to wait at all for this haha
Hope you liked it!
Will done
So far this is the only immediate, factual analysis that addressed
The lack of control on booster and ship
Loss of heat tiles.... you can see them falling off.... way before reentry begins !
Inadequate thruster sizing
Next launch.... when !?
Trust me, the heat tiles are not the final solution for starship. They're gonna keep giving problems. My idea: An ablative thermal blanket pulled over starship like a sock with a zipper that releases the thermal sock once heating phase is over. Once caught by the tower, a mechanism can pull a new thermal sock over starship. Super fast and reliable.
@@paulmichaelfreedman8334wtf 😆
A thermal protection prophylactic!
@@terranspaceacademy Call it what you like 😆it's massively cheaper and faster than tiles!
Yes, I'm happy now, that thing in the way of the speed and altitude was very, very annoying. Thank you 😮
You are most welcome. It did not show on my screen when creating...
Video made a mistake: Soviet Shuttle did *NOT* throw away boosters. The Soviet Shuttle used 4 liquid boosters instead of 2 solids. Soviet boosters would parachute down to the steppes of Kazakhstan and airbags would cushion landing. A flatbed truck with truck crane would pick them up and carry back to launch site. Boosters were designed to be used 10 times. However, Soviet main engines were attached to their external tank so expended with the tank.
Did not know that! Thank you. I saw where the "Hurricane" design was going to fly back.
2:01 you and almost every channel are missing the whole point. And I thought you would correct it @ 2:18 !
SpaceX is not trying to make an amazing rocket, which Starship is, it is trying to make 1000 amazing rockets. And launch all of them every two years!
SpaceX decision to use steel is for that purpose, a production line. The iteration rate and reusability are based on that decision.
Single use rockets based on aluminium and carbon simply don't help Elon Musk dream to have 100.000 people traveling to and from Mars every two years.
At the end of a decade or two Elon will have produced more rockets than Airbus and Boeing have produced commercial planes.
Gosh. Don't know how I missed that... with the whole factory assembly line and all... just slow I guess.
how much do the header tanks alter the centre of mass to balance things up as surely it's a pretty easy thing to computer model margins for re entry requirements?
It should be...
Wow, great job on this. Well thought out.
Thank you!
what about the challenger , wasnt that a failed tile? i prob missed something
Covering that later today.
You didn't talk much about the booster. Was it supposed to be on one engine when it fired to slow down? It appeared to me the steering fins where making wild sweeps to try to compensate.
It should have been more. They had a relight failure and blowout. The question is, spin due to engine failure or engine failure due to spin?
The live show they said the 13 inner engines were expected to relight to bring down the speed, before a soft crash into the ocean on the 3 core engines only. As he points out, and the same was on my mind watching the live, the imbalanced shutdown would be where I look first on why it did not relight, but hard to have physical evidence to guide us when the booster "landed" in the ocean at over 1000 meters per second. I do not mind the booster dying here because as his point early on... nobody but SpaceX and a few lighter rockets use reusable boosters. Recovery is just too complex.
Loved the launch though.
I agree that the Starship needs more energetic control thrusters. The slow roll was noticeable from the outset. The booster seemed to be having problems with the grid fins. Theses controls need to be beefed up and enhanced before they will be successful. I also liked the use of Inconel alloys suggestion. Inconel has been around a LONG time, and isn't that outrageously expensive. Hard to work with and I don't know how easy it would be to fabricate into rings for stacking?
Here's the problem. Hot gas thrusters from the tank ulage works while the engines are running. When they are not pressure drops and they don't work as well.
I think the booster engines failed because they didnt have enough fuel. The remaining fuel was floating as it came down.
A longer fuel feed line with a backflow preventer would enable the engines to fire long enough to allow the fuel in the tank to compress back down against the fuel intake port.
Space X needs to implement a fuel bag and pressure system like an ordinary well water pressure tank.
That's an interesting thought...
My theory is the booster had control issues as a symptom and not a cause. Just like the booster blowing up before it hit the water was, in my mind, a syptom. I think the apparent lack of control was due to the fact the speed was too great and put it out of velocity parameters. This caused the oscillations as the computer tried to correct but couldn't. Then the engines (build up of gasses due to the failed light attempt?) caused the explosion. As for Starship, I believe it was lack of control that killed it.
The engines had a relight failure too. The question is? Spin due to engine failure or vice versa?
Perhaps high speed at low altitude led to excessive back pressure of air into engine nozzles contributing to relight failure?
@@novanights2chevy597 that's my uniformed opinion
@@terranspaceacademy spin due to failure that allowed excess speed that the control computer couldn't account for
Were the thrusters really too weak, or were they not functioning at all?
Too weak... Prolonged use drops pressure. If the engines aren't on they can't repressurize.
Thank You! Great job!
Thank you so much!
There's not been nearly enough commentary about the shedding of debris (probably parts of tiles) that occurred at the point of re-entry. There were already a couple of tiles lost on launch.
What concerns me about Starship is structural dynamics on re-entry. Starship is essentially a soda can - a thin walled steel cylinder. Those flaps impose forces at specific points and thus the entire structure is subject to buckling forces. Also, there would be vibrational modes that will interact with the turbulence in the plasma - with potential positive feedbacks. Now add tile loss and the potential for "zipper" failure (where gas gets under the edge of adjoining tiles) and you've got lots of opportunities for cascading failure.
I agree that SpaceX may have to rethink it's thermal protection. Strange thing is that the original reason given for stainless steel was that it was well suited to transpirational cooling which is what was originally proposed.
Not many tiles flew off until it flew sideways on reentry. If they can fix the spinning issue I reckon that will solve all their issuex
@@zachb1706 What that probably demonstrates is the zipper effect. Tiles being levered off because of the hypersonic stream directed at their edge. Same thing happens when a tile is missing on the underside, during a descent with the correct attitude. What fixes this is an absolutely unbreakable tile mounting scheme (probably means a lot more mass) or going back to basics and inventing a TPS that doesn't use tiles.
They came in sideways and at one point went upside down... I'm surprised it didn't tear they all off.
Excellent analysis and theories. I wish some SpaceX engineer (or even Elon) could comment on this, or maybe be interviewed by you. That would be epic 😊
It would be awesome! Technical questions only. The man's private life is not my concern :-)
As it turns out the carbon fiber route is more expensive than that of stainless steel as SpaceX has found out.
Yes but a single use would be light enough to go to the Moon :-) single launch if done right.
Wasn’t the space shuttle Columbia lost because the external tank damaged the tiles on the left wing? During recently this caused a burn through and the shuttle broke up. I recall that on subsequent flights they used powerful telescopes to check the underside of the orbiting shuttle for missing tiles.
It was a carbon-carbon wing leading edge insert... not the tiles
Wouldn’t it be better to have the reaction control thrusters on the ends of the wings? Wouldn’t that give them more leverage?
It would indeed. Like the X-15.
Starship uses cold gas thrusters, not hot gas ones. Also, I think it uses oxygen, rather than methane. But I could be wrong about that.
Um.... Maybe you should do some more research, because it does use hot gas rather than cold gas, google it! Also, it uses methane and oxygen, that's how rockets work, you have the fuel(methane) and then you have the oxidizer(oxygen). Please make sure you have done enough research before you make these uneducated comments!
Yeah. He pictured a hot gas thruster.
It uses hot gas thrusters.
@@shawngadwa269Not the one he showed. It's just tank gas, not combustion hot gas thrusters.
I believe those are hypergolic thrusters used on Starship, similar to what was used on the space shuttle, Apollo and similar to what is used on Orion and Falcon 9. Hypergolic is just two different chemicals stored separately, which spontaneously ignite when combined. A cold gas thruster just uses a pressurized gas like nitrogen, the systems are dependent on a large tank size due to decreasing pressure over a period of time.
very good video.
the conclusions are plausible and logical.
Good structure of the video and clear explanations.
no lengths in the video to waste time.
I think your thoughts can help spacex further.
the fundamental problem of flight characteristics becomes one
big problem for spacex because of the weight distribution and
the wing design is difficult to change.
It's logical, but Spacex forgot maneuvering jets,
even though they have them with the capsule.
The staggering of the starship shows that no one is thinking about it
has thought about re-entry.
Losing heat tiles is a disgrace.
at the moment when the entire geometry changes
The Starship will eventually have different flight characteristics.
Spacex currently has excellent engines though
the rest is unusable.
or to put it more simply, they come up but guaranteed
not down.
There will definitely be nothing with 6 starts this year.
Thank you so much!
You touched on a number of good points. And yes, everybody else, so far, throws away their very expensive boosters. Thing is, it is SpaceX’s stated purpose to reuse theirs. So it’s failing to ‘land’ is technically a failure. Why they chose to attempt a standard landing profile, as opposed to trying to simulate a ‘chopstick’ landing at some arbitrary altitude to see if they could meet the necessary profile is a lost opportunity (which they did repeatedly during landing attempts with early Starships).
And the Elerons play no part in orienting Starship during atmospheric entry. The atmosphere is simply too thin. Watch the speed readout and you will see that Starship had slowed very little through breakup. And I totally disagree with the proposal to add hyperbolic engines to a vehicle intended to carry people on interplanetary voyages. Hydrazine is not the kind of material you want to live with long term. Thruster and control algorithms need work. Before IFT-4? We’ll see.
I think they'll try to hover over the water at some point soon to get the control right. Once they quit spinning :-)
That new alloy is awesome. I wonder how much it would cost to produce it at scale.
It is amazing. Like GRX810. Crazy stuff will be possible soon.
I commented elsewhere if shape contributed to loss of control. It looks like thruster size is also to blame, plus the vectoring limitation as installed. I kinda wondered how much vectoring the thrusters had.
SpaceX also needs to open an close the payload door thousands of times and speeds to test for fatigue and durability. It's a curved door which complicates linkages and hinges.
Also, did you notice the stuff flying past the camera? Heat tiles?
Should have been a camera on the exposed side of the starship to watch the stainless steel melt. Fascinating! As Spock would say.
Shaped like the original CTS it would have been stable... otherwise you need some serious RCS
This was an especially appreciated video. There are many, many videos out there that are very enthusiastic about starship but give no insight into the failures described.
Thank you!
You made very good observations. Starship may need to be more asymmetrical in order to orient itself.
I think both booster and ship suffered from programming errors. The booster grid fins over-corrected, inducing oscillations. The ship flaps had the ability to control the orientation of the ship once it reached the atmosphere, but they moved it into the wrong orientation several times. This could be an easy fix.
Regarding the RCS control, I have no idea what happened, but there was a lot of venting the whole time the ship was in orbit. Maybe it ran out of cryogenics to produce the gas for the RCS, or the amount of pressure was too low to be effective. They can't be venting propellant all the way to Mars. It needs refrigeration. Anyway, using ullage gas seemed like a good idea, but it looks like it doesn't work in practice. Hypergolics would be more reliable.
Or did one get stuck? Looked a lot like that one F9 booster...
A lot of tweaking of the flight software is in order with possible larger grid fins in later iterations. Same with the Starship itself slightly larger fins may be needed. Further hardening of internal structures and possible revisions of the slosh baffle system. Cargo door needs a lot of work to ensure fast smooth operation with a solid seal on closing along with a means to pre-vent the internal volume of the cargo bay as there was visible gas flow as the door opened which may have added to the control problems of Starship. Fuel transfer should not have unbalanced the ship. flow of gases out of the open cargo door seems a primary point of disruption. along with possible failures in the thruster system possible mistiming's of firings or insufficient force. The added flap idea sounds good.
Very good points...
Regarding metal superalloys, the cancelled VentureStar SSTO was planned to have a reusable Inconel thermal protection system in order to avoid the problems of the ceramic heat shield in the Space Shuttle.
We know Starship is using basically the same ceramic heat shield as the space shuttle, because someone compared Starship and Space Shuttle heat shield tiles with a microscope.
Looks like SpaceX is optimistic they can avoid the issues NASA had with ceramic tiles. I wouldn't be too surprised if they end up trying something else.
I loved the Venture Star!!
During the aborted Lockheed Martin VentureStar program, a new thermal Protection System developed by Rohr Inc. was announced. The system utilized a nickel-based superalloy developed by Inco Alloys International. The material features a high creep resistance and high strength at high temperatures alloy. At the time, it was loudly claimed it was safer and cheaper to maintain than the ceramic protection system used on the Space Shuttle. According to Lockheed the VentureStar's metallic heat shield would have eliminated 17,000 between-flight maintenance hours typically required to satisfactorily check (and replace if needed) the thousands of heat-resistant ceramic tiles that compose the Shuttle exterior. I have heard little about it since. I had high hopes SpaceX would adopt the VentureStar TPS for Starship. There are some rumors that a derivative of it is being used on hypersonic vehicle development. If anyone knows what happened to the seemingly promising development let us all know.
It would be interesting to measure the rate of climb in the initial seconds of launch and compare it to past launches/computed acceleration predictions given the weight. One could also compare post liftoff velocity with nominal and get insight into how the ship is doing.
It seems to have been on the money, same as IFT2 but it would be good to know for sure.
Regarding the booster landing, note how fast the booster is going when they attempt to start grid fin control. I was looking back at the landing video and, per SpaceX's timeline, the booster was to go transonic at T+6:36, 10s before it was to start the landing burn but, at T+6:36 on the video, the booster was 13km high and travelling at 3630kph (Mach 3) - definitely not subsonic! The supersonic speeds as you mention require different control algorithms. They had the first engine light at T+6:54 when it was 1km altitude and it was still travelling 1322kph (Mach 1.1). The booster did go subsonic when it hit the water but that was a bit too late. I am guessing they now know that they need a reentry burn. I heard it is used on F9 to keep the booster from getting too how so they though they didn't need it because the Starship Booster can handle higher temperatures.
That is a very good point... I would agree that a reentry burn is necessary. They are probably trying to conserve for "hovering" which the Falcon 9 does not do.
I really wish you were better informed... I'll try to watch again in a few months... ever hopeful....
Never give up! But since what we don't know is always infinite a hint of what you are talking about would be nice.
@@terranspaceacademy You show great character in your engagements and knowing that we have more to learn is the best quality of character that I know of. ❤ You are clearly intelligent, motivated, educated, even clever. I mean no slight to you in any way. I think the issue that I keep having with your channel is something that I had with school in general. Presenting yourself or product as educational, I expect more. In school, I often proved the school text books wrong and this drove me away from school. Created some distrust. I think if you put almost the same video up and weren't claiming to be an academy, I would not flinch. My general suggestion would be to have patrons or a discord where you can have trusted others double check your videos before posting.
Following are a few points that I think are ill informed in the above video.
1:52 making starships from aluminum or carbon fiber. I don't want to go deep into this, but just stripping down the stainless versions would do what you are looking for. To do aluminum or carbon fiber would be a monumental task with very little benefits. Stainless has been chosen for a reason and has proven itself.
3:50 Showing RCS thrusters as an example of what is controlling the ship. It uses only venting for RCS. Using ullage gas instead of dedicated thrusters of any kind.
5:10 (might be nit-picky and context sensitive) I do understand saying that the thrust vectoring is limited in the context of RCS/re-entry, but not only does raptor have the greatest angle of thrust vectoring of any orbital rocket engine (to my knowledge, 15 degrees) but it is entirely moot in the context of re-entry.
6:45 "Starship uses hot gas thrusters". I believe hot gas means burning fuel. Cold gas is simply venting compressed gasses. Warm gas would be heating that gas before venting it. So at best, the ullage venting rcs would be considered warm gas. I believe they are simply cold gas though.
8:05 Damage to heat tiles did not cause the loss of any shuttles? um... Columbia? This may be the most egregious statement. Loss of heat tiles was the direct cause of the loss of vehicle and 7 crew. ANYONE claiming to know anything about human spaceflight should not have said this. Full Stop.
8:40 Inconel. Are you suggesting that the entire starship be made of Inconel? This would show significant ignorance of all of the reasons that stainless steel is used. Stainless steel is around $3k per ton while Inconel is more like $40k+ per ton. Also, would you suggest in this case that no TPS is used? If so, this would cause a lot of issues with boil-off, if it could even be called that at the rates that would be present with out TPS.
That is all I have with a quick review. I truly do appreciate your efforts and goals. I wish you the best and hope that your channel is as successful as you dream. Any time people are creative, they open themselves to criticism. I hope that my comments do not discourage you in any way. ❤
Also on future Starships I believe SpaceX has plans to move the flaps upward on the cylinder towards the leeward side. That would provide natural stability when re-entering.
That would have the same effect and be a good idea I think...
I think SpaceX will stick with steel until they are sure they have no other options but to switch. The benefits of using off the shelf stainless steel really shine when it comes to simple production and ease to make on-the-fly adjustments.
They probably will retrofit some improved RCS thrusters for redundancy while they sort out all the issues that come with their new hot-gas thrusters.
I'm sure they will.
Great Article again. And Spacex gained a lot of valuable information re stability and heat tiles. I think that Spacex will not go for hypergolic Superdraco because of their philosophy of simplicity and because it will require more cleanup and turnaround time every launch. I think they should go for more flaps and larger control surfaces, maybe even small wings to increase drag and control orientation. The heat tiles have been a disappointment, I'm sure I saw dozens come loose in the video of the launch. If you added small wings, they could be actively cooled and maybe do away with the heat tiles altogether.
I agree. They'll use methane/Lox to better effect maybe.
I believe that the Falcon 9 tests were engineered with main focus on the boosters landing. And they succeeded in the entire test. I believe they need to work on delegating purpose and intent. Everything matters. Starship is massively complex. Focusing on getting equipment back to earth is much more paramount than reaching orbital altitude when you're still in the haphazard stages of testing. I'm spit-balling but I support my case.
That sounds plausible to me.
When is this 'ere the next flight?
I call six weeks.
Actually pretty hopeful; Nothing inherently wrong with the design other than certain inadequacies which just need augmentation, in ways that ought to be rather easy to accomplish.
I've seen the control surface you suggest referred to as a "beaver tail" on other ships - e.g. the B2 "Spirit".
That's right!
The rotation started in space - I think the RCS outright failed.
Or couldn't handle a real roll once it started, which is the same thing really.
We need to wait and see how much data they where able to harvest from this flight before redesign StarShip. I know I’m probably wrong but it kinda look like the Super heavy booster might have been running part of Falcons 9 re-entry program and it wasn’t able to compensate for the increase in size very well.
If Draco Where ever added it seems to me that fuel management issues would be the reason, like fuel slosh and initiating fuel transfer, but a better choice would be a very simple reliable small rocket engine that runs on the same fuel, the process would Similar to the way very large construction vehicles engines are started by small engine.
That's an interesting thought...
They were spnning before reentry. Maybe something was wrong with the RCS. If not, they need to upgrade like you said.
It's possible they had a stuck valve...
If a part needs to have superior strength and corrosion resistance at high temperatures, Inconel alloys are best. Inconel 625 in particular has good high strength properties at temperatures up to around 1000 deg. F and is weldable. You will find Inconel used in internal jet engine parts. I think the reason SpaceX uses 304L SS is due to cost and workability. Inconel is very expensive and difficult to machine. 304L also has better ductility which makes it tougher and more fatigue resistant.
It appears to me that SpaceX needs bigger more reliable thruster control jets and possibly larger aero control surfaces at the back end.
Indeed. Making this thing out of Inconel would be a nightmare... and a double hull would have a lot of mass.
I've been thinking about the booster. I wonder if the fall was enough to allow entrainment of gasses inside the fuel in the fuel tank. I was thinking why it was different from Falcon, and the only thing I could come up with is, weight doesn't matter when falling, everything falls at the same rate, neglecting air resistance. But when in the atmosphere, you have to factor in air resistance and atmospheric exposure cross section. Maybe Falcon's cross section to weight ratio is light enough to allow the fuel to stay settled while Starship's isn't. This is just idle speculation since I don't have the flight data to reference, so take it with a grain of salt.
Edit: I found video of the booster landing and I was wrong. It was slowing down before the engines fired
That's a good point! I'll do the math :-)
I wonder if bringing back the third fin would be of benefit?
That's a very good question...
When I think of faulty tiles, I think of what happened to Columbia. I wish they would develop a spray foam aerogel that could coat the ship. Or, a giant vat they could dip the entire ship underside in at once. Heat up the Starbrick material and dip it in and out. No chance of peeling heat tiles then.
Yeah, it's crazy, but it would be better to land on Mars with a full shield than have to program Robby the robot to scale up to the nose cone for a repair job.
That would leave nowhere for thermal expansion to go other than shatter the shield. The liles don't touch for a reason...
@@owensparks5013actually aerogel has a bajillion pours of air when it's put in a vacuum and cured.
Columbia failed from a frozen piece of foam hitting the carbon-carbon leading edge... no tile involved. Maybe Inconel would have survived.
Single use, putting the booster in orbit as space station building material is brilliant. build an orbital ship yard to re-use the engines...
We think so! :-)
I really want to see plans for a wet workshop.
The logo was in the way!
But I fixed it :-(
8:05 I am pretty sure the Columbia loss would be considered a thermal tile issue leading to a loss.
It was not my friend. It was due to damage to a leading edge carbon-carbon insert. Not at tile.
Wouldn't Starships's RCS be considered cold gas? I thought hot gas was when referring to a combustion/reaction process and thus more thrust. Starship was going to use hot gas, but they ditched it for simplicity.
That's an interesting question. The methane gas in the ullage is heated so the gas is how and gives better Isp than cold. At the same time there's no combustion so....
8:00 Yes, space shuttle heat tiles have caused an accident. Colombia burnt up in the atmosphere because it lost too many tiles during launch, killing everyone aboard.
It wasn't the tiles. A carbon-carbon insert was punctured.
Tiles will plague this system just like Shuttle. Rutan entry is the smart move. And yes he had a fully orbital system designed.
Rutan was a genius... both of them.
How about focusing on the Booster recovery to the point of a Falcon Heavy's accuracy. Once you've mastered this you can launch a proven craft configuration like say the Shuttle. A new improved Shuttle with the Tech available now would be a game changer.
Going back to the Shuttle would be a mistake I think. LEO only and low mass to orbit.
@@terranspaceacademy Did I say use the original Shuttles? If the Starship s Booster can become fully reusable it would replace three devices that doomed two Shuttles. Two Boosters side by side will get massive modern Shuttle past Hubble or the Moon.
There's some ridicule of Starship because it's not a "real" Moon rocket, as SLS is considered to be. However this may not be a fair comparison, because the SLS side boosters function as a third stage. I'm wondering whether the following change would be equal to or better than SLS. I.E, shorten the Starship booster to about 60% of normal. Then stack two of the shortened boosters, with the Starship providing the third stage.
That's interesting... So 40m each? Put a centaur third stage on it and it can do much more than SLS
The issues with reentry had nothing to do with the aerodynamics of the ship, it was tumbling well before it hit atmo
That's true. But a lot of capsules would have righted themselves.
@@terranspaceacademy only if they were close enough to the correct orientation or only rotating slowly. If they were already tumbling they would likely burn up before stabilizing. That's a lot of mass with a lot of inertia, and very little atmosphere for the control surfaces to correct it with no matter how you look at it
I agree. More robust RCS could compensate until the air is denser.
I’m almost sure that one of the shuttles that totally burned up did so because of the tiles under the wings falling off at some point or being damaged and the heat went through and everyone on board was burned up going over Texas
Not tiles though. Leading edge hit by frozen foam damaging the carbon-carbon insert. Real Engineering has a great episode on it.
@@terranspaceacademy but that was still a part of the thermal protection system. To differentiate it from a tile in this context is disingenuous.
@@warpedfusion no it's not. A tile falling off doesn't create a hole in the wing like the broken leading edge did, which exposed the internal structure to extreme heat. Also the Shuttle was an aluminum frame so it couldn't handle the heat as well as Starship which is stainless steel.
Given the current design, I wonder how they are going to protect the elevator channels they plan to install? That heat is going to wreck havoc on them, plus it's a weak point on the ship.
Perhaps SpaceX should take a few lessons from sci-fi on landing cargo ships. The ramp and/or doors are going to need thousands of openings and closings to test for fatigue and durability.
That's a good question.
Great job with the logo. And amazing intro!
How about more Starship-themed intro for the next one?🤩
The intro is a stock CZcams provided element.
@@dr4d1sI still want more Starship-themed intro for the next one, CZcams🚀
Will do :-)
I guess they don't want to use hypergaulic thrusters because they would make rapid reuseablilty harder.
That's right. They could use methylox ones though.
Original design for Starship wasn't a pointed cylinder but a blunt nosed, rounded triangular section,semi-lifiting body design with a trailing "belly" surface, and larger fins. Elon changed to the "pointy" round design because it "looked cool!" In spacecraft/aerodynamic design, functionality drives design... NOT what "looks cool". Maybe he should use some of the designers from Tesla Motors to design Starship. They couldn't possibly do a worse job. IMHO
And it should have stayed that way in my opinion :-)
Nah, cylinders are cheaper than triangular bodies, and he has to *pay* for thousands of these things (instead of just billing The Feds), so it matters - these prototypes are just proving out the giant factory. The "Make it Pointier!" thing was Elon riffing on a joke in SBC's movie "The DIctator".
@@dancingdog2790 Just to make sure, you are aware that *he* is billing 'The Feds' 3 billion for these prototypes that he ends up throwing in the ocean, right?
0:53 What are you talking about N1? The Soviet ship tried to fly 4 times and never went up more than half a kilometer!
What does it mean «the booster is lost»? On the street? In the forest? Where and how?
Booster go by by in the atmosphere burning up or into the drink. N1 failed but the design was solid. Just the control systems were faulty.
@@terranspaceacademy
No my friend, it's exactly the N1 design that is guilty!
*First Korolev’s error was the rocket’s frame!* Instead of using a perfect lightweight design when the rocket shell is the fuel tank, Korolev creates the external frame like a pyramid or the christmas tree. Inside he put spheric fuel tanks. A heavy rocket like that almost cannot fly!
*Second error was the engine.* All four flytes ended with the engine explosion and not because of the fault of control systems. The engine pump rotor turners so quickly and must be so precise, that soviet industry was not able to make it.
How SpaceX booster can burn in the atmosphere? It has no enough velocity to take fire as the ship does.
I Invision a future where heat tiles are a thing of the past, with new AI generated alloys and 3D printed shapes with channels for cooling. I hope this makes sense as I'm not wearing my glasses and typing on my phone with my thumb. LOL...
GRCop42 would work fine if we had active cooling.
All nuts and bolts all the time!
Indeed!
If you look at the old IPTS they had a flap.
I remember...
@@terranspaceacademy It’s more for the audience. I know that’s like saying water is wet to you. Lol.
IS IT EXPECTED to have SPEED DROP on hotstaging?
The booster yes... Starship not so much... There will be some but less than a full coast and pause.
I thought this was an analysis?
You didn't hear me pontificating about RCS issues? Anything further is guesswork at this point.
🙀
:-)
Transferring the cooling solution from Stoke to starship wouldn't be that simple, hydrogen have the most higher specific heat capacity from all substances (14j/g/°K)but the methane hc is only 2,2j/g/°K, so you need to take to orbit and back 6,3 more methane than hydrogen for the same effect.
Excellent point! But I still think it's a viable method :-)
@@terranspaceacademy probably it is, but the Stoke regenerative heatshild is a part of the propulsion system, for starship you need to add that only for re-entering, a pasive heatshild probably would weigh less and would be more reliable , if you don't like ceramic tiles heatshilds you can consider a radiative heatshield made from a metallic alloy, like the one that is planned for the New Glenn reusable upper stage.
There is merit to their design...
Watching the launch of Starship 3 filled me with hope that the world would be better place
Indeed. We need a safety valve for humanity.