Author Topic: Predictions for Starship IFT-4  (Read 27388 times)

Offline JohnsterSpaceProgram

Predictions for Starship IFT-4
« on: 03/16/2024 04:03 pm »
Hello again everyone! Now that it's been a few days since IFT-3 launched on March 14th, 2024, I thought I would start a predictions thread for IFT-4. Like the previous thread, you can either reply here with your predictions, or enter them on the IFT-4 predictions spreadsheet.

Also, my previous flight prediction threads can be found here...
IFT-3: https://forum.nasaspaceflight.com/index.php?topic=60003.0 (The post flight success section of the sheet has been unlocked, so anyone who hasn't put in how successful IFT-3 was to them on the sheet, should do that before submitting an IFT-4 prediction)

And you can find the predictions sheet I've created for IFT-4 here: https://docs.google.com/spreadsheets/d/19QQfI8sOaSBU0T3dqUbIkMoQk2Yfr8KiO0KRz-UrUt4/edit?usp=sharing.

With those introductions out of the way, I would like to share my predictions for the fourth integrated test flight of Starship.

Vehicles: Booster 11/Ship 29 (B11-S29)

Launch Date: May 2024

Flight Success Chance: 85% Successful

What I Would Consider As A Success: The ship surviving re-entry down to 45 KM in altitude (before presumably being lost), the booster slowing down more than it did during it's landing burn attempt on IFT-3, and at least half of the in-space demos/tests (such as a raptor relight if one is planned) being performed without any failures.

So, what are your predictions for flight 4? Also, don't forget to check out the IFT-4 launch predictions poll (https://forum.nasaspaceflight.com/index.php?topic=60544) by jongoff as well!  :)
I'm JohnsterSpaceProgram and I like watching Starship development! The first Starship orbital test flight was amazing to watch and I can't wait for future orbital flights!

Offline Metalskin

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Re: Predictions for Starship IFT-4
« Reply #1 on: 03/16/2024 08:23 pm »
This is a tough one. We have two elements:

1) Booster
 - I suspect that they will relight the booster engines for landing, but it will be a hard landing - too fast (though fingers crossed that I'm wrong)

2) Starship
 - successful vacuum relight of raptors in orbit, proving deorbit capability
 - fuel transfer - no idea
 - bay doors - incremental improvement but hard to call (I suspect a bit of engineering required here and may not happen for the next flight)
 - failure on reentry

I know I'm being pessimistic, I'm just wary as the booster landing is a lot harder than the falcon 9s, and the reentry is whole new territory and I think they have a lot to learn in this space, too many unknowns in my mind.
« Last Edit: 03/16/2024 08:25 pm by Metalskin »
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Offline meekGee

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Re: Predictions for Starship IFT-4
« Reply #2 on: 03/17/2024 05:44 pm »
Booster: all engines relight, hard impact but not at terminal velocity.

Ship: in-orbit tests successful, reentry, stable fall-down for a while, then failure during bellyflop.

Next day headlines: "SpaceX loses another rocket, how long can this chain of failures be allowed to continue".
ABCD - Always Be Counting Down

Offline alugobi

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Re: Predictions for Starship IFT-4
« Reply #3 on: 03/17/2024 05:49 pm »
Next day headlines: "SpaceX loses another rocket, how long can this chain of failures be allowed to continue".
Close...

"Elon Musk's Spacex loses another rocket, how long can this chain of failures be allowed to continue".

Offline wannamoonbase

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Re: Predictions for Starship IFT-4
« Reply #4 on: 03/17/2024 06:23 pm »
Iíll get into the spreadsheet this week.

But I think:

Booster: Repests its successes to date and nails the engine relight landing burn, grid fins better performance.

Essentially booster looks completely successful.   Maybe not accuracy on the RTLS flight or landing position, but theyíll look good and complete each step.

Ship: I havenít read this anywhere, but perhaps some full size Starlink satellite mass simulators.  Check out the dispenser but on a non orbital trajectory they donít have to worry FCC so much. 

I think they will come up with solutions to proper control vehicle orientation.  Even if itís a quick, heavy, inefficient fix.  Right now maintaining orientation and pointing that heat shield in the right direction throughout re-entry is the priority.  (Maybe this will be repurposing some F9 or Dragon V1 or V2 Dracoís and super Dracoís.). 

Ship will get further into re-entry and they will have control either till a landing, or breakup. 

S28ís shield looked good, from what we saw, but still plenty of things to learn and experience.  That has to be the Biggest want, more re-entry data, on IFT-4. 
Wildly optimistic prediction, Superheavy recovery on IFT-4 or IFT-5 (Welp a little early on IFT-4, but still have a shot at 5)

Online yg1968

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Re: Predictions for Starship IFT-4
« Reply #5 on: 03/18/2024 01:29 am »
I expect that SpaceX will resolve the roll issue and will be able to re-light the engines on Starship on IFT-4. The booster should be able to land successfully in the water but I don't expect the ship to survive re-entry into Earth's atmosphere.
« Last Edit: 03/18/2024 01:33 am by yg1968 »

Online InterestedEngineer

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Re: Predictions for Starship IFT-4
« Reply #6 on: 03/18/2024 01:34 am »
if SpaceX puts obviously visible higher performance RCS system in place, I give Starship 50/50 of surviving re-entry.  0% otherwise.  They didn't get data past the oscillations on reentry and didn't get deep into the heating regime (they'd only lost about 1000km/hr or so before losing data), so there's still a ton to learn even with better control mechanisms.

Booster should make it back to gentle splashdown status, aka full mission success.  My guess is the problems on IFT-3 are easily solvable (wind sheer, control loop problems, and landing relight issues), mostly because they got good data the whole time, and those are all reasonably easy problems to solve.

Offline Star-Dust

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Re: Predictions for Starship IFT-4
« Reply #7 on: 03/18/2024 08:03 am »
Spacex major problem is the heatshield, ship already landed succefully so this is not an issue.

Personnally the pace of launches is too slow we're going to be out of schedule.


Offline Yggdrasill

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Re: Predictions for Starship IFT-4
« Reply #8 on: 03/18/2024 08:12 am »
My predictions for "IFT-4" (if that is what it will be designated) are:

1. Launch in the first half of June.
2. Booster performs a successful soft landing in the gulf.
3. Starship completes insertion into the target orbit. This may include a burn at apogee.
4. Payload bay door functions correctly. If Starlink satellites or satellite dummies are carried, they are successfully deployed.
5. If a propellant transfer test is performed, it is successful.
6. A deorbit burn (actual or test) is successfully performed.
7. Starship successfully makes it through entry. (60/40 chance)
8. Starship has a controlled decent into the ocean. (55/45 chance)

Offline wannamoonbase

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Re: Predictions for Starship IFT-4
« Reply #9 on: 03/18/2024 01:37 pm »
I expect that SpaceX will resolve the roll issue and will be able to re-light the engines on Starship on IFT-4. The booster should be able to land successfully in the water but I don't expect the ship to survive re-entry into Earth's atmosphere.

I agree with you completely and you used about 10% of the words I did.  (I will try to be better, Lol)


Edit: I would not be surprised if Spacex added a ship landing burn to the flight plan to maximize learning oppurtunities.
« Last Edit: 03/18/2024 01:45 pm by wannamoonbase »
Wildly optimistic prediction, Superheavy recovery on IFT-4 or IFT-5 (Welp a little early on IFT-4, but still have a shot at 5)

Offline daveglo

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Re: Predictions for Starship IFT-4
« Reply #10 on: 03/18/2024 01:45 pm »
Artemis and Starlink remain the near-term focus for Starship.  In that light, mission priorities should be:

1. Assuming the FT-3 propellant transfer created some issues, repeat this test with updated procedures.
2. Complete engine relight demonstration.  This is critical for future flights, as it enables orbital operations.
3. Assuming the FT-3 payload bay door test had issues (sure looked like it), repeat test (assumes pre-flight modifications are completed).  I doubt we see any Starlink mass simulators, but there are Starlink sats on hand if they want to expend one in testing.  My own opinion is that no sats fly until door is well-proven.

Secondary objectives include:
1. Improved booster landing performance (grid fin control and landing burn engine relight).
2. Improved Starship space flight controls (this might be a big ask, as I suspect ship thruster mods are necessary).
3. More Starship re-entry excitement (we're a long way from an intact water impact).

Offline wannamoonbase

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Re: Predictions for Starship IFT-4
« Reply #11 on: 03/18/2024 02:03 pm »
Artemis and Starlink remain the near-term focus for Starship.  In that light, mission priorities should be:

1. Assuming the FT-3 propellant transfer created some issues, repeat this test with updated procedures.
2. Complete engine relight demonstration.  This is critical for future flights, as it enables orbital operations.
3. Assuming the FT-3 payload bay door test had issues (sure looked like it), repeat test (assumes pre-flight modifications are completed).  I doubt we see any Starlink mass simulators, but there are Starlink sats on hand if they want to expend one in testing.  My own opinion is that no sats fly until door is well-proven.

Secondary objectives include:
1. Improved booster landing performance (grid fin control and landing burn engine relight).
2. Improved Starship space flight controls (this might be a big ask, as I suspect ship thruster mods are necessary).
3. More Starship re-entry excitement (we're a long way from an intact water impact).

100% agree, that more flight experience means better over all understanding on how to fly both vehicles.  Even as they learn to fly both they will learn how far they can push each and better learn how accurate they can be. 

They really need to get good at flying these accurately to make catch attempts.
Wildly optimistic prediction, Superheavy recovery on IFT-4 or IFT-5 (Welp a little early on IFT-4, but still have a shot at 5)

Offline wannamoonbase

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Re: Predictions for Starship IFT-4
« Reply #12 on: 03/18/2024 02:18 pm »
Spacex major problem is the heatshield, ship already landed succefully so this is not an issue.

Personnally the pace of launches is too slow we're going to be out of schedule.

The pace will increase, once they can make some flights without having incidents that the FAA wants to review then the pacing element could be pad turn around and vehicle production times.

Then they will be hardware constrained, but in the second half of this year the starfactory will start spooling up.

The higher flight rate is coming but its a few flights out right now.
Wildly optimistic prediction, Superheavy recovery on IFT-4 or IFT-5 (Welp a little early on IFT-4, but still have a shot at 5)

Offline SpaceTripper

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Re: Predictions for Starship IFT-4
« Reply #13 on: 03/18/2024 03:02 pm »
Next day headlines: "SpaceX loses another rocket, how long can this chain of failures be allowed to continue".
Close...

"Elon Musk's Spacex loses another rocket, how long can this chain of failures be allowed to continue".

Close...

Elon Musk's SpaceX loses another rocket, how much longer can we allow this monster to play with his deadly toys?
« Last Edit: 03/18/2024 03:03 pm by SpaceTripper »

Online DanClemmensen

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Re: Predictions for Starship IFT-4
« Reply #14 on: 03/18/2024 03:12 pm »
The pace will increase, once they can make some flights without having incidents that the FAA wants to review then the pacing element could be pad turn around and vehicle production times.
I saw no evidence that FAA paperwork delayed IFT-3 by even one day. SpaceX needed to analyze the  events that caused the formal word "mishap" to be used, and they would have needed that analysis even if FAA had not been involved at all. SpaceX needed to fix the issues that they found and would have needed to do so even if they were not formally required as formal "mitigations". They did a test flight, they observed problems, they analyzed the problems, they designed and implemented fixes. This is exactly why they do test flights.

IFT-2 was delayed by the required IFT-1 investigation, but that was because it triggered a mandatory environmental investigation. Even that extra delay was short relative to the time required to rebuild the pad. We can hope that will not happen again.

I'm not sure about the launch rate. I think we will see pad turnaround reduced to less than a week, so production becomes the rate limiter. Production rate appears to be increasing. We might even see a Depot and a Tanker launched in the same week toward the end of the year, while they are still testing and analyzing EDL for Starlink SS.

Offline Alberto-Girardi

Re: Predictions for Starship IFT-4
« Reply #15 on: 03/18/2024 03:38 pm »
I will put the predictions later in the spreadsheet.

I might be a dissenting opinion, but I don't think that for now Ship reentering is the to priority. I think that demonstrating an in-flight relight and stable attitude are much more important. That is because SpaceX needs to start testing the refueling and also start deploying starlinks.

Even if the ship demonstrates a successful reentry, are the regulators going to allow them to try to land one on the second try overflying land? Where are the going to land it? The old landing pad is no more and all the currently built Ships have no legs. About tower catching, it has been years since we have heard something about that for the Ship. Also the ship has only 6 engines and is smaller than the booster, making losing one a lot less costly.



What IFT4 needs to demonstrate is the ability of Starship to be used to launch heavy payload, by showing that it can deorbit safely, thus allowing IFT5 to go into stable orbit, deploy starlink and maybe start to test refueling.
What I would look to about reentry is demonstrating that the Ship is aerodynamically stable at hypersonic speed. I don't think it would be uncontrollable (they made the Shuttle stable with 1970s technology so surely SpaceX would have been able to simulate this), but it would allow to tune the parameters for the next try.

Unfortunately booster recovery is far away (not a chance before late 2024) because of the risk to the tower, but making it work will drastically increase flight rate because soon flights will be limited by boosters. So demonstrating a soft and on target splashdown is IMO more important than a successful reentry.

Flight pairing: B11/S29 the 5th full stack couple

Timing:
Prelaunch ops: I would guess as fast if not faster than IFT3 for the booster, so I would expect a static fire ~1 month after launch, so April 15
I think S29 needs some work to its attitude control system, so I would guess for a static fire around the end of April.

From there I expect 1 week of checkouts, then stack for WDR on the second week of May and launch 1 week later.  I will give a symbolic date of May 20th, 1 year and 1 month after the first flight.

Expectation:

Flight path: same as IFT3 unless FAA gets really convinced it is safe to do a full orbit

Anything less than a perfect orbital insertion will be a big resounding failure. They have to show that at least it works as an expandable launcher.

I expect the booster to soft land. They seemed so close last time and they went from a failure to ignite the boostback burn on IFT2 to acing it. They are improving fast.

I expect S29 to mantain controll and to perform the in space burn. I think it will demonstrate a good entry initially. Problems will come with peak heating. I give it a 50/50. But if it fails, I think it is possible it would fail at peak deceleration because of damage to the structure done at peak heating.

What do you think about my predictions? Don't be afraid to critique, at the end we are just guessing.
« Last Edit: 03/18/2024 03:46 pm by Alberto-Girardi »
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Offline wannamoonbase

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Re: Predictions for Starship IFT-4
« Reply #16 on: 03/18/2024 04:24 pm »
The pace will increase, once they can make some flights without having incidents that the FAA wants to review then the pacing element could be pad turn around and vehicle production times.
I saw no evidence that FAA paperwork delayed IFT-3 by even one day. SpaceX needed to analyze the  events that caused the formal word "mishap" to be used, and they would have needed that analysis even if FAA had not been involved at all. SpaceX needed to fix the issues that they found and would have needed to do so even if they were not formally required as formal "mitigations". They did a test flight, they observed problems, they analyzed the problems, they designed and implemented fixes. This is exactly why they do test flights.

IFT-2 was delayed by the required IFT-1 investigation, but that was because it triggered a mandatory environmental investigation. Even that extra delay was short relative to the time required to rebuild the pad. We can hope that will not happen again.

I'm not sure about the launch rate. I think we will see pad turnaround reduced to less than a week, so production becomes the rate limiter. Production rate appears to be increasing. We might even see a Depot and a Tanker launched in the same week toward the end of the year, while they are still testing and analyzing EDL for Starlink SS.

I should have been more clear.  I wasn't blaming the FAA for delays, IFT-3 was clearly hardware limited until maybe the last week.  But when the vehicles fail, especially like in IFT-1 and 2 there are more extensive investigations needed, and also hardware changes.

The lessons and changes from IFT-3 to IFT-4 look like they should be shorter, maybe more software than hardware and likely some hardware changes already implemented between models. 

I could see there being a push toward a ship to ship propellant transfer by the end of this year.  Whether a proper tanker or just another ship to receive propellant, we will see.

I have been following space closely for more than 3 decades and this program since 2016, finally it's flying and getting exciting.  The pace only increases from here.
Wildly optimistic prediction, Superheavy recovery on IFT-4 or IFT-5 (Welp a little early on IFT-4, but still have a shot at 5)

Online yg1968

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Re: Predictions for Starship IFT-4
« Reply #17 on: 03/18/2024 05:13 pm »
I might be a dissenting opinion, but I don't think that for now Ship reentering is the to priority. I think that demonstrating an in-flight relight and stable attitude are much more important. That is because SpaceX needs to start testing the refueling and also start deploying starlinks.

I don't think that you are in the dissent on the importance of making Starship work at least as an expendable LV for now. Having said that, I think that SpaceX would also like like to test re-entry as quickly as possible in order to see if changes to Startship's heatshield are necessary.
« Last Edit: 03/18/2024 06:16 pm by yg1968 »

Online DanClemmensen

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Re: Predictions for Starship IFT-4
« Reply #18 on: 03/18/2024 05:22 pm »
I might be a dissenting opinion, but I don't think that for now Ship reentering is the to priority. I think that demonstrating an in-flight relight and stable attitude are much more important. That is because SpaceX needs to start testing the refueling and also start deploying starlinks.

I don't think that you are in the dissent on the importance of making Starship works at least as an expendable LV for now. Having said that, I think that SpaceX would also like like to test re-entry as quickly as possible in order to see if changes to Startship's heatshield are necessary.
It all goes together. It is critical to test and solve the attitude control problem. But to do that they must fly a test mission. If attitude control succeeds on that mission, then they can test in-flight relight. If relight succeeds on that mission, then they can test re-entry. If re-entry succeeds then can test controlled descent. If controlled descent works, then they can test (pseudo) landing. But the very first and most fundamental test is attitude control.

Offline Framryk

Re: Predictions for Starship IFT-4
« Reply #19 on: 03/18/2024 05:59 pm »
I might be a dissenting opinion, but I don't think that for now Ship reentering is the to priority. I think that demonstrating an in-flight relight and stable attitude are much more important. That is because SpaceX needs to start testing the refueling and also start deploying starlinks.

I don't think that you are in the dissent on the importance of making Starship works at least as an expendable LV for now. Having said that, I think that SpaceX would also like like to test re-entry as quickly as possible in order to see if changes to Startship's heatshield are necessary.
It all goes together. It is critical to test and solve the attitude control problem. But to do that they must fly a test mission. If attitude control succeeds on that mission, then they can test in-flight relight. If relight succeeds on that mission, then they can test re-entry. If re-entry succeeds then can test controlled descent. If controlled descent works, then they can test (pseudo) landing. But the very first and most fundamental test is attitude control.

I'm really hoping for repetition / consistency from IFT-3 to IFT-4 with the Booster 33 engines, hot staging and Ship full set of engine Raptor performance. Consistency on doing the same thing well each time is important to build confidence at the launch phase.

I'm assuming that until they solve attitude control they can't solve Raptor relight, and without Raptor relight they are limited to quasi-orbital tests i.e. no full orbits and gainful deployment of Starlinks. So this has to be the major focus of IFT-4.

I've predicted better Booster performance with more relights but not enough for a soft splashdown; Ship performance is good and the Pez dispenser is tested with a mass simulator (with cameras please!) that will also burn up; attitude control lasts for a Raptor relight but then goes wonky and the re-entry suffers, so the Ship doesn't make a belly-flop water splashdown.

I predict trying to solve the attitude control issue will take the majority of the time to IFT-4, I'm being pessimistic with a stab at June 19th (but would love it to be early, ideally May the Fourth).


 

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