Author Topic: Falcon Heavy Post May 22/2012, Engineering Master Speculation Thread  (Read 165743 times)

Offline ArbitraryConstant

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I can recall a few speeches Musk has given saying that Heavy will be reusable, and I think I actually recall hearing Shotwell say that in person.
Yepp, me too.
They may aspire to make it reusable, and Musk may consider it a failure if it isn't eventually reusable, but it won't be reusable initially, they don't require reusability to be profitable, and the cores are not identical to each other even though there's a lot of commonality that will help with manufacturing.

Offline Lars_J

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I can recall a few speeches Musk has given saying that Heavy will be reusable, and I think I actually recall hearing Shotwell say that in person.
Yepp, me too.
They may aspire to make it reusable, and Musk may consider it a failure if it isn't eventually reusable, but it won't be reusable initially, they don't require reusability to be profitable, and the cores are not identical to each other even though there's a lot of commonality that will help with manufacturing.

Indeed. And the FH will make its debut much earlier than F9-Reusable. If that is successful, only then can you expect a FH-Reusable version.

Online Lee Jay

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But this argument cuts both ways.  If you can survive 2 engines out, then with 99% engines you get 99.75% mission success.

No.  What's going on right now proves this is faulty logic.

Falcon 9 flight 5 is currently delayed for several months because of a single engine failure. [ ... ]  this is not an acceptable outcome even if the vehicle makes it to orbit.  [ ... ] That lack of understanding will lead to shutdowns like the one we are in right now, and it will lead to customers fleeing to other providers if not understood and corrected so that it doesn't happen again.
This is true so far, but does not have to be so.  Look at airplanes - it's relatively common for flights containing paying, civilian, non-waiver signing passengers to lose half their engines.

Not 1 in every 20 flights, or the entire fleet that uses those engines would be immediately grounded.  And there have been groundings for engine failures, including the recent grounding of the A380 fleet which was despite a far better engine reliability record than 1-in-40.
« Last Edit: 12/10/2012 08:29 pm by Lee Jay »

Offline Elmar Moelzer

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Quote
They may aspire to make it reusable, and Musk may consider it a failure if it isn't eventually reusable, but it won't be reusable initially, they don't require reusability to be profitable, and the cores are not identical to each other even though there's a lot of commonality that will help with manufacturing
Yes, not initially, but I was not expecting anyone to assume that. It will be reusable eventually. I am pretty sure that he cores will be identical (for some reason I remember someone mentioning that), but you may be right about that not actually being the case due to the cross feeding equipment. I might have just remembered that wrong and it might have just been the engine block.

Offline LouScheffer

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This is true so far, but does not have to be so.  Look at airplanes - it's relatively common for flights containing paying, civilian, non-waiver signing passengers to lose half their engines.

Not 1 in every 20 flights, or the entire fleet that uses those engines would be immediately grounded.  And there have been groundings for engine failures, including the recent grounding of the A380 fleet which was despite a far better engine reliability record than 1-in-40.
Yes, but that's only since the FAA can afford to be picky since there exist perfectly good 1-in-1,000,000 alternatives. 

For rockets, the alternatives are much worse than airplanes.  Which would you rather ride on - a shuttle with a demonstrated 1 in 75 chance of killing its passengers, or a Soyuz that (from memory) needed the escape system in 2 of roughly 100 crewed launches, or a rocket with a 1 in 20 chance of losing an engine, and then a 4 in 5 chance of making it to the desired orbit anyway?

Offline beancounter

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Timeline would be for the initial flight. I recall it being stated earlier this year that the FH test flight was supposed to occur this year or early next year, although none of that was officially pinned down yet.

Still shows as 2012  on this: http://www.spacex.com/launch_manifest.php

Column heading:
Quote
Vehicle Arrival at Launch Site

cheers, Martin

Like I said or sometime in Q1 2013. And I also said, its not officially pinned down yet.

The fact that its up there is bogus, IMO, because I doubt it will even be ready to go to the pad this year. They should not have that there IMO, this going to be like similar delays in the past where they would have been better off not listing the schedule.

Perhaps I am being overly pessimistic but at this point I'd rather not see massively incorrect dates being thrown around by SpaceX anymore.
 

Yes SpaceX are really tardy unlike other companies or say NASA? Bad SpaceX   ;)
Beancounter from DownUnder

Offline PCSTEL

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I want to believe, but I am still having trouble buying into the 27 engine thing.
Why?  Given their demonstrated reliability, they should only lose about 2 every 3 missions.
Exactly.  There's the "why".
But this argument cuts both ways.  If you can survive 2 engines out, then with 99% engines you get 99.75% mission success.

No.

What's going on right now proves this is faulty logic.

Falcon 9 flight 5 is currently delayed for several months because of a single engine failure despite the fact that the vehicle continued on to orbit.

The business can't tolerate this sort of thing.  If they want to be on a launch cadence of 1 a month or so, they have to have zero engines fail on the flights.  My sarcasm of 2 failures every 3 flights seems to have been a little understated - this is not an acceptable outcome even if the vehicle makes it to orbit.  The engines aren't designed to fail, and if they do that means you don't understand something about the design, the manufacturing, the environment or something else that led to an unexpected failure.  That lack of understanding will lead to shutdowns like the one we are in right now, and it will lead to customers fleeing to other providers if not understood and corrected so that it doesn't happen again.
Speaking of customers fleeing. 

I noticed in Salo's last US launcher update that both the Orbcomm 2G launch and the Thaicom 6 launch have now been noted as (or 2014).

I believe this only leaves CRS2 and CRS3 now (October 15th) and SES-8 and the Falcon 9v1.1 / 5 meter faring/ Vandenberg qualification MDA flight still solid on the SpaceX 2013 manifest.  If SES-8 goes to Ariane 5, SES CEO stated a decision was to be made in November/Decemer, then Space X could end up with only 3 scheduled launches in 2013.

Offline mlindner

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I want to believe, but I am still having trouble buying into the 27 engine thing.
Why?  Given their demonstrated reliability, they should only lose about 2 every 3 missions.
Exactly.  There's the "why".
But this argument cuts both ways.  If you can survive 2 engines out, then with 99% engines you get 99.75% mission success.

No.

What's going on right now proves this is faulty logic.

Falcon 9 flight 5 is currently delayed for several months because of a single engine failure despite the fact that the vehicle continued on to orbit.

The business can't tolerate this sort of thing.  If they want to be on a launch cadence of 1 a month or so, they have to have zero engines fail on the flights.  My sarcasm of 2 failures every 3 flights seems to have been a little understated - this is not an acceptable outcome even if the vehicle makes it to orbit.  The engines aren't designed to fail, and if they do that means you don't understand something about the design, the manufacturing, the environment or something else that led to an unexpected failure.  That lack of understanding will lead to shutdowns like the one we are in right now, and it will lead to customers fleeing to other providers if not understood and corrected so that it doesn't happen again.
Speaking of customers fleeing. 

I noticed in Salo's last US launcher update that both the Orbcomm 2G launch and the Thaicom 6 launch have now been noted as (or 2014).

I believe this only leaves CRS2 and CRS3 now (October 15th) and SES-8 and the Falcon 9v1.1 / 5 meter faring/ Vandenberg qualification MDA flight still solid on the SpaceX 2013 manifest.  If SES-8 goes to Ariane 5, SES CEO stated a decision was to be made in November/Decemer, then Space X could end up with only 3 scheduled launches in 2013.
Those are backup in case SpaceX fails. This is normal practice, this is not a doubt at SpaceX specifically, but launch vehicles in general.

Offline modemeagle

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Falcon Heavy from Boca Chica and having SI boost forward to the Florida Keys for recovery.

EDIT: ADDED AXIS TITLES PER REQUEST
« Last Edit: 01/06/2013 07:44 pm by modemeagle »

Offline newspacer

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Quote

Yes SpaceX are really tardy unlike other companies or say NASA? Bad SpaceX   ;)

SpaceX is very optimistic when it comes to schedules. It is a wonder they ever meet any of the deadlines they set.
« Last Edit: 01/05/2013 02:27 am by newspacer »

Offline Robotbeat

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While I agree SpaceX is pretty optimistic at times (I voted for just 3 launches in 2013), keep in mind:
A) NET is not a deadline. It stands for "No /Earlier/ Than."
B) "arrival at launch site"
and, of course, they really aren't too different from other new launch vehicles. See Antares, for instance. And that's based on a basically existing upper stage and a lower stage based on Zenit work.
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Offline joek

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I believe this only leaves CRS2 and CRS3 now (October 15th) ...
SpaceX CRS-3 launch was moved forward to 30-Sep-2013 a couple weeks ago.

Offline MP99

Falcon Heavy from Boca Chica and having SI boost forward to the Florida Keys for recovery.

Superb, many thanks for that, and all the work you put in.

18t to 30t is a hell of a leap in performance for a reusable, and seems to me to justify SpaceX's interest in Boca Chica. Basically, a 40% drop in cost-per-pound-to-LEO, and I presume a substantial jump in GTO as the main customers for this sort of performance. Could easily justify the hassle of trucking S1 back for a follow-on mission - I'm assuming they'll at least go back to McGreggor for checkout anyway.



You also have to remember a lofted trajectory is going to go higher and the entry is then going to be higher in drag during entry, increasing stress on the stage.  The stress on my SI simulation may have to be optimized more as the stage is going to get 14g acceleration at entry; it spends ~20 seconds over 6g acceleration.

As a bonus, looks like the S0s only see ~4.5g during re-entry, and S1 ~5.5g. If the stages can be orientated not to hit side-on, those sound pretty survivable.

cheers, Martin

Edit: added m/e quote re 14g.
« Last Edit: 01/05/2013 11:59 am by MP99 »

Offline MikeAtkinson

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You also have to remember a lofted trajectory is going to go higher and the entry is then going to be higher in drag during entry, increasing stress on the stage.  The stress on my SI simulation may have to be optimized more as the stage is going to get 14g acceleration at entry; it spends ~20 seconds over 6g acceleration.

On ascent S1 has to carry a full SII + payload + some of its own propellants (mass Mx) at almost 4g acceleration (= 50 Mx force). I would think it would be strong enough to withstand 14g (= 150 My force) when it is almost empty (just landing propellant remaining), mass My on descent.

It looks like Mx/My > 3 so descent accelerations should not be a problem. The distribution of forces will be different however, and only SpaceX can model a stage in sufficient detail to determine whether extra strengthening may be needed.

Offline mlindner

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Falcon Heavy from Boca Chica and having SI boost forward to the Florida Keys for recovery.

Could you label your axes? It is hard to someone relatively uninformed with these types of graphs to read them.

Offline modemeagle

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Online Chris Bergin

This thread diverted into 60+ posts worth of CRS-1 Engine 1, when we have a thread for that discussion. Split and merged.

Do not drag threads off topic.

If the SpaceX sections become too hard to keep on top of, it'll be regular members read only (L2 members can post).
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Online Norm38

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How is this (FH Transporter/Erector) suppose to be simpler than other methods?

Because they didn't have to build a 33 story building, on wheels, in an earthquake zone?  What I see on Page 63 of the update thread looks a lot simpler than this:
http://www.launchphotography.com/Delta_4-Heavy_NRO_L-26_MST.html
« Last Edit: 02/12/2013 04:43 pm by Norm38 »

Offline Robotbeat

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How is this (FH Transporter/Erector) suppose to be simpler than other methods?

Because they didn't have to build a 33 story building, on wheels, in an earthquake zone?  What I see on Page 63 of the update thread looks a lot simpler than this:
http://www.launchphotography.com/Delta_4-Heavy_NRO_L-26_MST.html
How are you going to integrate the payload? You need some sort of tall structure anyway.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline JBF

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Just like they do with Pegasus but larger.

How is this (FH Transporter/Erector) suppose to be simpler than other methods?

Because they didn't have to build a 33 story building, on wheels, in an earthquake zone?  What I see on Page 63 of the update thread looks a lot simpler than this:
http://www.launchphotography.com/Delta_4-Heavy_NRO_L-26_MST.html
How are you going to integrate the payload? You need some sort of tall structure anyway.

Ok if someone could edit that so it only shows a thumbnail I'd appreciate it.
« Last Edit: 02/12/2013 08:27 pm by JBF »
"In principle, rocket engines are simple, but thatís the last place rocket engines are ever simple." Jeff Bezos

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