Author Topic: New F9 Upper Stage  (Read 14610 times)

Offline wannamoonbase

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New F9 Upper Stage
« on: 05/16/2017 06:46 pm »
Mods please delete or merge if deemed appropriate.

There seems to have been a new US on the last two launches.

Do we know anything about it? 

Does it provide more lift or just more coast and profiles?

New COPVs?
Wildly optimistic prediction, Superheavy recovery on IFT-4 or IFT-5

Offline dror

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Re: New F9 Upper Stage
« Reply #1 on: 05/16/2017 06:50 pm »

There seems to have been a new US on the last two launches.


What showed you that?
Space is hard immensely complex and high risk !

Re: New F9 Upper Stage
« Reply #2 on: 05/16/2017 07:01 pm »

There seems to have been a new US on the last two launches.


What showed you that?

https://forum.nasaspaceflight.com/index.php?topic=41560.msg1678508#msg1678508

There seems to be significant physical changes externally, and the fact that it did a long coast on the last flight indicate the upper stage has been upgraded again.

Offline macpacheco

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Re: New F9 Upper Stage
« Reply #3 on: 05/16/2017 10:14 pm »
The significant jump in expandable performance supports some upgrades to F9 too. In fact there's some L2 information about this, but I can't go into any details (hint, hint, L2 is awesome).
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Offline biosehnsucht

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Re: New F9 Upper Stage
« Reply #4 on: 05/16/2017 11:13 pm »
At least two different people have posted that they've heard from reliable sources (but of course, can't name them etc) that the last two flights were Block 4 second stages, but Block 3 first stages

edit: as docmordrid referenced below, I meant to say "...people have posted on reddit..." :P :D
« Last Edit: 05/17/2017 05:01 am by biosehnsucht »

Online docmordrid

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Re: New F9 Upper Stage
« Reply #5 on: 05/17/2017 01:03 am »
That Block 3/Block 4 mix has also been reported on Reddit.

https://www.reddit.com/r/spacex/comments/6bed12/comment/dhm1o04
« Last Edit: 05/17/2017 01:09 am by docmordrid »
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Offline envy887

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Re: New F9 Upper Stage
« Reply #6 on: 05/17/2017 01:18 am »
The booster was definitively run at higher thrust than SES-10 (which was known to be Block 1). The MVac does NOT appear to have been run at higher thrust, but it's certainly possibly that the Block 4 upper stage doesn't include any thrust upgrade.

Image from: https://forum.nasaspaceflight.com/index.php?topic=42389.0

Offline ugordan

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Re: New F9 Upper Stage
« Reply #7 on: 05/17/2017 07:50 am »
The booster was definitively run at higher thrust than SES-10 (which was known to be Block 1).

Hold on. SES-10 carried all the recovery hardware and its associated mass with it, Inmarsat was a stripped booster. Have you considered whether the booster dry mass difference is in the right ballpark to explain the hotter ascent of B1034? My gut feeling tells me it's not enough, but even BOTE numbers trump gut feelings...

How does this boost phase compare to EchoStar 23?
« Last Edit: 05/17/2017 07:52 am by ugordan »

Offline stcks

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Re: New F9 Upper Stage
« Reply #8 on: 05/17/2017 01:06 pm »
The booster was definitively run at higher thrust than SES-10 (which was known to be Block 1).

Hold on. SES-10 carried all the recovery hardware and its associated mass with it, Inmarsat was a stripped booster. Have you considered whether the booster dry mass difference is in the right ballpark to explain the hotter ascent of B1034? My gut feeling tells me it's not enough, but even BOTE numbers trump gut feelings...

How does this boost phase compare to EchoStar 23?

Yeah, the analysis needs to be done with Echostar-23 and Inmarsat-5. If you do that, you'll see that that Echostar actually accelerates faster, but Inmarsat burns for longer and reaches a higher MECO velocity of about 50 m/s more. To me, nothing to indicate higher thrust engines, but possibly some evidence for more prop load.

Offline envy887

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Re: New F9 Upper Stage
« Reply #9 on: 05/17/2017 01:29 pm »
The booster was definitively run at higher thrust than SES-10 (which was known to be Block 1).

Hold on. SES-10 carried all the recovery hardware and its associated mass with it, Inmarsat was a stripped booster. Have you considered whether the booster dry mass difference is in the right ballpark to explain the hotter ascent of B1034? My gut feeling tells me it's not enough, but even BOTE numbers trump gut feelings...

How does this boost phase compare to EchoStar 23?

The acceleration in the first 160 seconds was 12.5% higher (on average) for I5F4 than SES-10. It's relatively constant throughout the boost phase, which indicates that the dry mass of the booster (whose ratio to the total mass of the vehicle constantly changes as fuel is burned) has a fairly small effect. Which intuitively makes sense: if the recovery hardware masses 5 tonnes, that's only about 2% of the 200+ tonnes vehicle mass at 160 seconds.

I5F4 also accelerated through transonic much more aggressively than SES-10, which is interesting.

Offline Kaputnik

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Re: New F9 Upper Stage
« Reply #10 on: 05/17/2017 01:31 pm »
The booster was definitively run at higher thrust than SES-10 (which was known to be Block 1).

Hold on. SES-10 carried all the recovery hardware and its associated mass with it, Inmarsat was a stripped booster. Have you considered whether the booster dry mass difference is in the right ballpark to explain the hotter ascent of B1034? My gut feeling tells me it's not enough, but even BOTE numbers trump gut feelings...

How does this boost phase compare to EchoStar 23?

Yeah, the analysis needs to be done with Echostar-23 and Inmarsat-5. If you do that, you'll see that that Echostar actually accelerates faster, but Inmarsat burns for longer and reaches a higher MECO velocity of about 50 m/s more. To me, nothing to indicate higher thrust engines, but possibly some evidence for more prop load.

Inmarsat had a later prop load => colder prop => more prop.
"I don't care what anything was DESIGNED to do, I care about what it CAN do"- Gene Kranz

Offline abaddon

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Re: New F9 Upper Stage
« Reply #11 on: 05/17/2017 01:38 pm »
but possibly some evidence for more prop load.
It is reasonable to assume there was more prop load as they used the new fast-load procedure for the first time on this flight, so the prop should have been colder and denser than in previous flights with the longer/slower load procedure.

EDIT: Yeah what he said :)
« Last Edit: 05/17/2017 01:40 pm by abaddon »

Offline stcks

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Re: New F9 Upper Stage
« Reply #12 on: 05/17/2017 02:34 pm »
but possibly some evidence for more prop load.
It is reasonable to assume there was more prop load as they used the new fast-load procedure for the first time on this flight, so the prop should have been colder and denser than in previous flights with the longer/slower load procedure.

EDIT: Yeah what he said :)

It is definitely a reasonable assumption, but of course burn time is also affected by throttle and MECO velocity affected by trajectory. 50 m/s isn't very much for the first stage at that point in its flight. It could simply have used more prop residuals than Echostar. Bottom line - I don't want to claim it as fact since I dont know -- it could have had more prop, but other reasonable explanations also exist.

Offline acsawdey

Re: New F9 Upper Stage
« Reply #13 on: 05/17/2017 02:39 pm »
I5F4 also accelerated through transonic much more aggressively than SES-10, which is interesting.

From the comparison graph, I5F4 flew a more lofted trajectory, so maybe transonic happened at higher altitude, lower dynamic pressure?

I would assume that the reason for SES-10's flatter trajectory is to reduce re-entry heating as it was flying to ASDS not taking a one-way trip like I5F4.

Offline IntoTheVoid

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Re: New F9 Upper Stage
« Reply #14 on: 05/18/2017 01:31 am »
The booster was definitively run at higher thrust than SES-10 (which was known to be Block 1).

How / where is SES-10 known to be Block 1? From the quote below it seems that SES-10 was flown as a Block 3, which was born as a Block 2 and upgraded using some Block 1 processes. But that doesn't make it a Block 1 vehicle.

Former intern at KSC gives some very interesting details about 1021:

https://www.reddit.com/r/spacex/comments/62aqi7/rspacex_ses10_official_launch_discussion_updates/dfl9xge/

Quote
I've been waiting so long for this! I interned at LC-39A while the refurb was going on and boy did B1021 give us trouble! I'm so happy to finally see my baby fly!

Edit: since people are asking for more info, I'll give a couple fun problems we ran into.

- Trying to upgrade parts from block 2 to block 3, failing to install them three times, then giving up and trying (and succeeding with) a method from block 1
- Trying to remove parts that weren't originally intended to be removable
- Discovering parts on the booster that theoretically didn't exist before it launched

So, 1021 was a Block 2 booster that's been upgraded to Block 3, if this person is correct. More details in the thread.

Offline envy887

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Re: New F9 Upper Stage
« Reply #15 on: 05/18/2017 01:20 pm »
The booster was definitively run at higher thrust than SES-10 (which was known to be Block 1).

How / where is SES-10 known to be Block 1? From the quote below it seems that SES-10 was flown as a Block 3, which was born as a Block 2 and upgraded using some Block 1 processes. But that doesn't make it a Block 1 vehicle.

Former intern at KSC gives some very interesting details about 1021:

https://www.reddit.com/r/spacex/comments/62aqi7/rspacex_ses10_official_launch_discussion_updates/dfl9xge/

Quote
I've been waiting so long for this! I interned at LC-39A while the refurb was going on and boy did B1021 give us trouble! I'm so happy to finally see my baby fly!

Edit: since people are asking for more info, I'll give a couple fun problems we ran into.

- Trying to upgrade parts from block 2 to block 3, failing to install them three times, then giving up and trying (and succeeding with) a method from block 1
- Trying to remove parts that weren't originally intended to be removable
- Discovering parts on the booster that theoretically didn't exist before it launched

So, 1021 was a Block 2 booster that's been upgraded to Block 3, if this person is correct. More details in the thread.

See:

I haven't seen any evidence showing that they aren't aligned.

I have, there's plenty.

Quote from: Spiiice (employee)
I... I actually don't know how the blocks line up with the version numbers. Version numbers are pretty much strictly used outside the company and by Elon.

Quote from: Foximus05 (ex-employee)
Correction. [SES-10] was a block 1 (crs8) and wont fly again. Block 3 boosters could have multiple flights before being retired.

...

Former coworkers of mine that still work there referred to the CRS8 core as a block 1 when we were talking about it last weekend.

Quote from:  DSBromeister (ex-intern)
Trying to upgrade parts [on B1021] from block 2 to block 3, failing to install them three times, then giving up and trying (and succeeding with) a method from block 1

Quote from: skiboysteve (employee)
The impression [in SpaceX fan communities] of what the blocks are has never been verified as true. But everyone here acts like its a fact. It's just been repeated enough times...

Offline macpacheco

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Re: New F9 Upper Stage
« Reply #16 on: 05/18/2017 04:39 pm »
I though the understanding was:
- F9 Block 1 was the first generation F9 with M1C
- F9 Block 2 was the first F9 with M1D, octaweb, must higher thrust levels vs M1C
- F9 Block 3 was the resized F9 after chilled RP1 / deep cryo LOX permitted resizing of RP1/LOX tanks and a substantial increase in propellant capacity, modest thrust upgrade, just enough to allow for the heavier Block 3 to launch with similar acceleration as Block 2, but more prop gave this configuration a good increase in GTO and LEO performance
- F9 Block 4 has perhaps already partially flown or is about to be entered into service. A little more thrust apparently without more prop
- F9 Block 5 is the fullest performance, apparently the maximum M1D thrust SpaceX is comfortable for launches

No block 1s were recovered.
Successful recovery began with Block 2.

Can somebody set the record straight ? What I am missing in the block versions ?

Was there any Block 2 boosters reflown or planned to be reflown ?

Edit: Its now clear that my view is wrong, and Block I starts with the first deep cryo LOX / chilled RP1 booster. That actually explains Block Is being refurbed into Block IIs and IIIs.
« Last Edit: 05/18/2017 06:56 pm by macpacheco »
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Offline rockets4life97

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Re: New F9 Upper Stage
« Reply #17 on: 05/18/2017 04:49 pm »
Can somebody set the record straight ? What I am missing in the block versions ?

Was there any Block 2 boosters reflown or planned to be reflown ?

The conventional wisdom as you repeated is wrong -- see envy889's post above quoting old_sellsword for examples.

My current understanding (which could be wrong) is below.

There are 3 major versions of F9: 1.0, 1.1, and 1.2.
Version 1.2 will have 5 blocks: 1.2 block I, 1.2 block II, 1.2 block III, 1.2 block IV, and 1.2 block V.

This would make sense of the quote from Elon saying block IV is like version 2.5 (e.g. 1.25 if you keep the 1).

There are major changes between the 3 major versions (e.g. switch to octoweb, stage stretches). Although the jump from 1.0 to 1.1 appears to be bigger than 1.1 to 1.2. The block changes on the other hand are small revisions, some noticeable on the outside, and much probably not.

Offline stcks

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Re: New F9 Upper Stage
« Reply #18 on: 05/18/2017 04:55 pm »
Can somebody set the record straight ? What I am missing in the block versions ?

Block versions have been confusing. Unfortunately they are not as simple as you would like and there have been different uses of "Block" throughout the Falcon 9 history.

Consider the following: http://i.imgur.com/4fXmQYR.png. From this table you can see that F9 v1.0 was referred to at some point as Block 1 and F9 v1.1 as Block 2.

However, from the employee comments cited in the posts above, it appears that F9 v1.2 has also had a Block 1, 2, 3 and now (presumably) 4 and in the future a Block 5.

I wish it were clear and concise, but alas it is not.

Was there any Block 2 boosters reflown or planned to be reflown ?

We simply do not know which boosters are from v1.2 block 2, we can only guess. It is possible that B1023 or B1025 could have been from block 2 and thus would be reflown on a FH flight, but we don't know.

Offline Johnnyhinbos

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Re: New F9 Upper Stage
« Reply #19 on: 05/19/2017 02:10 am »
Man, I think people try too hard to ascribe logical, meaningful understanding to some of the stuff Elon says. The Old Testament had the same problem. Elon is flippant. He's sarcastic and off the cuff. He even sometimes has fun with people at their expense. He's Elon.

Don't kill yourself trying to ascribe characteristics and attributes to his VX.Y series and try to fit that into the Block (I-V) series. Just let it roll. When they launch crew to the ISS, we'll then - there you have a proper Block V.

What if he threw out "42"? I think it very might well cause actual seizures...
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Offline AncientU

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Re: New F9 Upper Stage
« Reply #20 on: 05/19/2017 09:52 am »
He did throw out 42*.
Engine number on ITS...

* and chuckled
« Last Edit: 05/19/2017 09:53 am by AncientU »
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Offline tdperk

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Re: New F9 Upper Stage
« Reply #21 on: 05/19/2017 11:21 am »
What if he threw out "42"? I think it very might well cause actual seizures...

If he says it while having a towel thrown over his shoulder and a bag of herring in his pocket, I will be deeply worried...

...about how to get past the leopard.

Offline MP99

Re: New F9 Upper Stage
« Reply #22 on: 05/20/2017 05:24 pm »
I5F4 also accelerated through transonic much more aggressively than SES-10, which is interesting.

From the comparison graph, I5F4 flew a more lofted trajectory, so maybe transonic happened at higher altitude, lower dynamic pressure?

I would assume that the reason for SES-10's flatter trajectory is to reduce re-entry heating as it was flying to ASDS not taking a one-way trip like I5F4.

From the earlier posts, if extreme subcooling allowed for a greater prop load, the increased GLOW would have reduced acceleration. If it's correct that acceleration was greater on this flight, then that would (also?) imply greater thrust?

If acceleration was notably greater on this flight, then perhaps a more lofted trajectory was necessary to avoid very high maxQ aero loads.

Cheers, Martin

Offline orulz

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Re: New F9 Upper Stage
« Reply #23 on: 06/14/2017 01:01 am »
The maximum flow rate of the turbopumps is measured in terms of volume of propellant, not mass, right? The same volume of denser, colder propellant flowing through the pumps would mean more propellant mass which would by definition mean more thrust, right?

Offline envy887

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Re: New F9 Upper Stage
« Reply #24 on: 06/14/2017 02:14 am »
The maximum flow rate of the turbopumps is measured in terms of volume of propellant, not mass, right? The same volume of denser, colder propellant flowing through the pumps would mean more propellant mass which would by definition mean more thrust, right?
Pushing more mass through a sonically choked nozzle requires more pressure. Pumping more mass into a chamber​ operating at higher pressure requires a lot more power, which has to come from the gas generator turbine. Getting more power from a turbine means running it at higher temp, pressure, speed, or all three... The turbine durability is probably the limiting factor here.

Online Robotbeat

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Re: New F9 Upper Stage
« Reply #25 on: 06/14/2017 02:24 am »
The maximum flow rate of the turbopumps is measured in terms of volume of propellant, not mass, right? The same volume of denser, colder propellant flowing through the pumps would mean more propellant mass which would by definition mean more thrust, right?
Correct to first order.
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