SpaceX Falcon 9 - EchoStar 23 - March 16, 2017 - DISCUSSION

[mme]

IMO not only loss of performance due to loading procedures, but also from reduced LOX volume in S2 (it has one more COPV, so less LOX).
I can't do the math on how much less is 1 COPV worth of LOX volume in dV, but I think it might have more impact than the overall slightly warmer LOX.

(Layman's thinking here..)

I think they got a 15% increase when they moved to densified LOX including the move from 4 COPVs to 3 COPVs.  That performance increase is spread across both stages so my guess is that the densification itself is the major factor.  Both for the total mass of propellent and from the mass/second of propellent they can run through the turbo-pumps.  But I don't have the numbers or knowledge to back it up.  (shrug)

[Zed_Noir]

Breaks your heart, doesn't it... 

I don't think so, I think it's a great opportunity to see what this bird can do.  Stripping the reusability weight and maybe run to depletion.  Give the bird a good ride.

Agreed, this would be a good flight for a bird that's already flown once.

Like watching an airplane take off and the discard it's landing gear, "to see what it can really do".
....

Ahem. Need I remind you of the first manned rocket interceptor. The Messerschmitt Me 163 Komet, which eject the landing gear after takeoff. Supposedly also the first aircraft to go supersonic.

[yg1968]

https://twitter.com/elonmusk/status/822926184719609856

Looks like it's going to be expendable

edit/gongora: 
Question on Twitter: "@elonmusk Next SpaceX flight (Echostar) has v heavy GTO payload (5500kg) Will Falcon fly expendable, or try low-margin droneship landing?"
Elon's Answer: "@gdoehne Expendable. Future flights will go on Falcon Heavy or the upgraded Falcon 9."

Here is an article on this:
http://arstechnica.com/science/2017/01/spacex-may-be-about-to-launch-its-final-expendable-rocket/

[CameronD]

Ahem. Need I remind you of the first manned rocket interceptor. The Messerschmitt Me 163 Komet, which eject the landing gear after takeoff. Supposedly also the first aircraft to go supersonic.

Not according to: https://en.wikipedia.org/wiki/Sound_barrier

The Luftwaffe test pilot Lothar Sieber (April 7, 1922 – March 1, 1945) may have inadvertently become the first man to break the sound barrier on 1 March 1945. This occurred while he was piloting a Bachem Ba 349 "Natter" for the first manned vertical takeoff of a rocket in history. In 55 seconds, he traveled a total of 14 km (8.7 miles). The aircraft crashed and he perished violently in this endeavour.

(..not that that it's at all relevant to the topic of discussion here - but it does make interesting reading from the couch whilst we wait for lift-off..)
 

[Orbiter]

https://twitter.com/elonmusk/status/822926184719609856

Looks like it's going to be expendable

edit/gongora: 
Question on Twitter: "@elonmusk Next SpaceX flight (Echostar) has v heavy GTO payload (5500kg) Will Falcon fly expendable, or try low-margin droneship landing?"
Elon's Answer: "@gdoehne Expendable. Future flights will go on Falcon Heavy or the upgraded Falcon 9."

Here is an article on this:
http://arstechnica.com/science/2017/01/spacex-may-be-about-to-launch-its-final-expendable-rocket/

I'm willing to be it's not the last expendable mission. BulgariaSat-1 apparently has a similar mass to EchoStar-23 per the NSF SpaceX Manifiest.

[gongora]

I'm willing to be it's not the last expendable mission. BulgariaSat-1 apparently has a similar mass to EchoStar-23 per the NSF SpaceX Manifiest.

BulgariaSat-1 may be lighter than that, it's hard to find a good mass estimate on that one.  Inmarsat 5 F4 and Intelsat 35e should both be much heaver (6-6.1mt).

[manoweb]

I'm willing to be it's not the last expendable mission. BulgariaSat-1 apparently has a similar mass to EchoStar-23 per the NSF SpaceX Manifiest.

Did not Mr. E. Musk say future flights will go on an upgraded version of the F9, that might have performance and re-usability upgrades?

[mme]

I'm willing to be it's not the last expendable mission. BulgariaSat-1 apparently has a similar mass to EchoStar-23 per the NSF SpaceX Manifiest.

Did not Mr. E. Musk say future flights will go on an upgraded version of the F9, that might have performance and re-usability upgrades?

When Block 5 and FH are flying.  But that's not going to be for awhile (end of year according to the article linked above.)  Until then, the largest payloads will be expendable.

[MATTBLAK]

Since the landed stages are not the Block 5 configuration; are they the most likely to be used for expendable missions?

[psionedge]

Well to some extent this expendable launch would have been a good candidate for a reused booster

It's an expensive payload so it's probably best to be conservative.

IMO not only loss of performance due to loading procedures, but also from reduced LOX volume in S2 (it has one more COPV, so less LOX).
I can't do the math on how much less is 1 COPV worth of LOX volume in dV, but I think it might have more impact than the overall slightly warmer LOX.

(Layman's thinking here..)

Also the mass increase of the extra COPV in S2 which would directly impact the payload.
When you think about that both stages in F9 have an ISP less then 350 it's pretty impressive they can do GTO payloads that size at all without resorting to adding a third stage.

Or strap on a solid rocket booster or two. Still don't get why SpaceX won't do that. They can spend a little more in the expendable column (currently just fuel) to easily enable recovery of something like 80% of the launch cost.

[Jet Black]

That would be a whole new production pipeline that would be obsolete when the FH is up and running.

[hkultala]

Or strap on a solid rocket booster or two. Still don't get why SpaceX won't do that. They can spend a little more in the expendable column (currently just fuel) to easily enable recovery of something like 80% of the launch cost.

Many reasons:

1) SpaceX does not manufacture SRBs.
2) SpaceX rocket cores do not have attachment points for SRBs.
3) SpaceX pads don't have flame trench points fro SRB's
4) Additional staging events increase risk
5) SRB's are typically integrated on the rocket while the rocket is vertical. SpaceX does it's integration horizontally, and horizontal integration is MUCH cheaper



So, create totally new rocket integration facility, change all the integration procedures, craeate a new launch pad, strengthen the rocket to hav all the loads paths and attachment points, increase risk to payload, buy some expensive bosters from elsewhere.

And do this all just to be able to recover first stage on one launch?

No, absolutely no sense at all.

[meekGee]

Breaks your heart, doesn't it... 

I don't think so, I think it's a great opportunity to see what this bird can do.  Stripping the reusability weight and maybe run to depletion.  Give the bird a good ride.

Agreed, this would be a good flight for a bird that's already flown once.

Like watching an airplane take off and the discard it's landing gear, "to see what it can really do".
....

Ahem. Need I remind you of the first manned rocket interceptor. The Messerschmitt Me 163 Komet, which eject the landing gear after takeoff. Supposedly also the first aircraft to go supersonic.

Neat, but it had landing skids...

If a plane is modified in such a way it can't land in order to achieve some performance metric, then great, by nobody would claim that this is what the plane can really do.

Landing is considered part of the flight profile.

[starhawk92]

So GTO from Florida is OCISLY for <= 5300kg (SES-9) and non-return for >= 5500kg until late 2017?

[kevin-rf]

Neat, but it had landing skids...

If a plane is modified in such a way it can't land in order to achieve some performance metric, then great, by nobody would claim that this is what the plane can really do.

Landing is considered part of the flight profile.

Well if you want the first reuse after a vertical flight and landing, I guess the winner would be Mercury-Redstone 1 with it's four inch flight.

[whitelancer64]

Neat, but it had landing skids...

If a plane is modified in such a way it can't land in order to achieve some performance metric, then great, by nobody would claim that this is what the plane can really do.

Landing is considered part of the flight profile.

Well if you want the first reuse after a vertical flight and landing, I guess the winner would be Mercury-Redstone 1 with it's four inch flight.

MR-1 was never used for another flight after its return to Huntsville. It was eventually put on display at the Space Orientation Center of Marshall Space Flight Center.

[RonM]

Neat, but it had landing skids...

If a plane is modified in such a way it can't land in order to achieve some performance metric, then great, by nobody would claim that this is what the plane can really do.

Landing is considered part of the flight profile.

Well if you want the first reuse after a vertical flight and landing, I guess the winner would be Mercury-Redstone 1 with it's four inch flight.

MR-1 was never used for another flight after its return to Huntsville. It was eventually put on display at the Space Orientation Center of Marshall Space Flight Center.

Yes. This kind of confusion occurs when the rocket designation and the flight designation are the same. Same problem with keeping track of which F9 first stage is being used on a F9 launch.

[old_sellsword]

Neat, but it had landing skids...

If a plane is modified in such a way it can't land in order to achieve some performance metric, then great, by nobody would claim that this is what the plane can really do.

Landing is considered part of the flight profile.

Well if you want the first reuse after a vertical flight and landing, I guess the winner would be Mercury-Redstone 1 with it's four inch flight.

MR-1 was never used for another flight after its return to Huntsville. It was eventually put on display at the Space Orientation Center of Marshall Space Flight Center.

Yes. This kind of confusion occurs when the rocket designation and the flight designation are the same. Same problem with keeping track of which F9 first stage is being used on a F9 launch.

SpaceX has different flight and rocket designations.

[cscott]

Since the landed stages are not the Block 5 configuration; are they the most likely to be used for expendable missions?

It's not clear how extensive the changes for block 5 are going to be, and how much refurbishment SpaceX is willing to do.  The legs already have to be removed from a landed stage for transport.  It may be that some recovered "block 4" stages are refurbished into block 5 falcons.  Or it may be that launch pace is too important and/or the cost of properly refurbishing a block 4 is so high that they will throw the block 4s away.  But I expect they'd still try to land any missions which are capable of it; I think they are still learning useful data from each attempt.  They might try more higher-risk triple-engine landing burns on block 4 falcons, for instance.

[old_sellsword]

It may be that some recovered "block 4" stages are refurbished into block 5 falcons.  Or it may be that launch pace is too important and/or the cost of properly refurbishing a block 4 is so high that they will throw the block 4s away. 

According to an employee, there's no cost effective way to retrofit a stage from one Block to another.