Gwynne Shotwell Interview - June 22, 2017 on The Space Show

[cscott]

Just "putting raptor on falcon for purposes of testing" would still require big changes to the GSE to support the additional propellant. It's not a cheap test.

[Lobo]

Just "putting raptor on falcon for purposes of testing" would still require big changes to the GSE to support the additional propellant. It's not a cheap test.

You are correct, it wouldn't.  But it might be "cheaper" than testing a new engine on a new booster and upper stage...especially given how large scale those new stages would be.  Might be good to have some flight history on the engine first perhaps?

Just speculating a way that Shotwell's comments could be accurate without meaning turning over the whole Falcon fleet to methalox, and the issues of then what do you do with all of those kerolox boosters which have a lot of service life left in them, and having a mixed fleet.

And if the experimental F9-Raptor were a good performer and reliable, they may then consider start transitioning new cores to that design, and then slowly start upgrading pads to methalox and basing the new boosters there while flying the older boosters out of the kerolox pads.  And slowing upgrading pads and retiring kerolox boosters as they get to the end of their service life.  And slowly turn over the fleet over time.

But once they get their kerolox boosters all certified for flying government payloads, they may not want to mess with that design too much, depending on how it could impact their certifications.

[ThereIWas3]

But didn't she say that a Raptor has already been tested multiple times?  So they already have delivery and storage facilities in place to handle the propellant.  The engine can be tested quite a lot without being connected to a rocket body.   Eventually, yes, the test stand that holds Falcon rockets would need some plumbing modifications.

[RocketmanUS]

Just "putting raptor on falcon for purposes of testing" would still require big changes to the GSE to support the additional propellant. It's not a cheap test.

You are correct, it wouldn't.  But it might be "cheaper" than testing a new engine on a new booster and upper stage...especially given how large scale those new stages would be.  Might be good to have some flight history on the engine first perhaps?

Just speculating a way that Shotwell's comments could be accurate without meaning turning over the whole Falcon fleet to methalox, and the issues of then what do you do with all of those kerolox boosters which have a lot of service life left in them, and having a mixed fleet.

And if the experimental F9-Raptor were a good performer and reliable, they may then consider start transitioning new cores to that design, and then slowly start upgrading pads to methalox and basing the new boosters there while flying the older boosters out of the kerolox pads.  And slowing upgrading pads and retiring kerolox boosters as they get to the end of their service life.  And slowly turn over the fleet over time.

But once they get their kerolox boosters all certified for flying government payloads, they may not want to mess with that design too much, depending on how it could impact their certifications.

US only, might be for Texas launch site, at least to start with.
I don't think the engine could throttle down enough for landing if the engines were on the first stage.

Edit:
Raptor on US would allow testing of Raptor vav.
Test out self pressurization for propellants.
Later could test in-space propellant transfer. No need for added helium for pressurant. Also would test out the propellants that would be used on ITS.

Use a F9 that has flown already to lower test cost. Could be a dummy payload or a reused Dragon for Dragon Lab mission for low cost.

[Chalmer]

"Looking at the utility of it [Raptor] on Falcon"

If old space "common sense" had prevailed at SpaceX there would be no Falcon 9 but a Falcon 3 at best. There would not have been any Grasshopper, let alone a reusable first stage. And there most decidedly would not have been ITS. And Dragon probably would not exist either given the old space mantra that launch service providers provide launches, not spacecraft.

It's undeniably a good thing that SpaceX is around. They are shaking things up. Disruptive. An industry that has been stuck in the same old patterns for the better part of 4 decades is finally beginning to move into a new direction.

It is "old school" NASA that financed CRS resulting in F9 and Dragon. Without which SpaceX may never have built F9.

Even a blind chicken sometimes finds a corn. 

And you mean COTS, CRS is the service contract.

[Negan]

Nothing she said pointed to just a RUS.  A mixed vehicle is not the Spacex way.

I don't think the engine could throttle down enough for landing if the engines were on the first stage.

If RocketmanUS is correct how could she not be referring to a RUS?

[spacenut]

Liquid natural gas (methane) is not that hard to do.  I worked with a natural gas company.  We liquified it, transported in via tractor trailer, etc.  The same equipment for LOX can be converted to liquid methane.  It is not a show stopper.  People are making a bigger issue out of this than necessary.  It is going to have to be done for Raptor anyway at some point.  Why not earlier than sooner and test the Raptor Vacuum, improve performance of FH and F9. 

I do not see the first stage changing, kerolox is probably the best heavy lifting first stage there is.  That is why it was chosen for Saturn V.  Upper stages are different, they need higher ISP for higher orbits and deep space probes. 

[calapine]

so Jim, do you think it would be worth the pain to switch Falcon to all methane?

New first stage, New upper stage, new tanks due to different density of Methan vs RP1, plus I suspect new tooling due to different diameter...

That would be an entire new launcher project.

[rsdavis9]

so Jim, do you think it would be worth the pain to switch Falcon to all methane?

New first stage, New upper stage, new tanks due to different density of Methan vs RP1, plus I suspect new tooling due to different diameter...

That would be an entire new launcher project.

That's why I think they should do something easy which doesn't get thrown away at the end.
S1 BFR, full methalox raptor.
Put S2 on top and stage higher with bigger payloads.

Conversely you could do S1 with Al-Li first.
Also could use subscale raptor.
Would result in a stage that eventually you will retire for the full one later.

[Lobo]

Use a F9 that has flown already to lower test cost. Could be a dummy payload or a reused Dragon for Dragon Lab mission for low cost.

The modifications might be extensive enough that they may wan to build a new one in Hawthorne, rather than chop up a flown booster that could be flying and generating revenue for them.

[Jim]

Liquid natural gas (methane) is not that hard to do.  I worked with a natural gas company.  We liquified it, transported in via tractor trailer, etc.  The same equipment for LOX can be converted to liquid methane.  It is not a show stopper.  People are making a bigger issue out of this than necessary. 

No, it is people that don't understand rocket science that are making an issue of the non existent methane upper stage.

This has nothing to do on handling methane.  The issue is adding to the F9 system.  It is disruptive.

[RocketmanUS]

Use a F9 that has flown already to lower test cost. Could be a dummy payload or a reused Dragon for Dragon Lab mission for low cost.

The modifications might be extensive enough that they may wan to build a new one in Hawthorne, rather than chop up a flown booster that could be flying and generating revenue for them.

Same F9 1st stage as is , just a new Raptor US.
So this is just speculating on some of what has been said.
Less disruptive if done at Texas launch site ?

[rakaydos]

Liquid natural gas (methane) is not that hard to do.  I worked with a natural gas company.  We liquified it, transported in via tractor trailer, etc.  The same equipment for LOX can be converted to liquid methane.  It is not a show stopper.  People are making a bigger issue out of this than necessary. 

No, it is people that don't understand rocket science that are making an issue of the non existent methane upper stage.

This has nothing to do on handling methane.  The issue is adding to the F9 system.  It is disruptive.

To be fair, everyone's heard of Saturn 5, which was a mixed kerlox/hydrolox rocket. What did apollo do differently that made mixed fuels a good idea?

[Jim]

To be fair, everyone's heard of Saturn 5, which was a mixed kerlox/hydrolox rocket. What did apollo do differently that made mixed fuels a good idea?

It was for performance and not cost.

[JasonAW3]

To be fair, everyone's heard of Saturn 5, which was a mixed kerlox/hydrolox rocket. What did apollo do differently that made mixed fuels a good idea?

It was for performance and not cost.

Jim,

      Wasn't there some discussion early on during Apollo about switching over to a LH/LO fuel mix?

[envy887]

I do not see the first stage changing, kerolox is probably the best heavy lifting first stage there is.  That is why it was chosen for Saturn V.  Upper stages are different, they need higher ISP for higher orbits and deep space probes.

If they hit Raptor's performance goals or anything close it will blow Merlin and every other engine away. They won't need kerolox. Moving forward with Raptor is obviously desirable. The only question is what impact that will have on the rest of their operations.

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[Eerie]

      Wasn't there some discussion early on during Apollo about switching over to a LH/LO fuel mix?

I can't imagine anyone sane agreeing to fly on that.

[RoboGoofers]

She would have to say that they're "looking into it" because that's what the Air Force paid them to do.