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SpaceX Vehicles and Missions => SpaceX Reusability => Topic started by: Chris Bergin on 10/03/2013 11:03 pm

Title: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Chris Bergin on 10/03/2013 11:03 pm
Super work by by Yves-A. Grondin:

http://www.nasaspaceflight.com/2013/10/musk-plans-reusability-falcon-9-rocket/

We've also released the audio and transcript out of from the post-launch presser:
http://forum.nasaspaceflight.com/index.php?topic=32719.msg1105469#msg1105469
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: AndyX on 10/03/2013 11:27 pm
Thanks for writing that article Yves!

I really hope they think about video coverage for that first attempt.  Would be amazing to see that coming back down!
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: yg1968 on 10/03/2013 11:30 pm
Thanks for writing that article Yves!

I really hope they think about video coverage for that first attempt.  Would be amazing to see that coming back down!

Thanks. They will have video of part of the descent of the Cassiope flight. They said in about a week (last Sunday) which means any day now.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Martin FL on 10/03/2013 11:56 pm
Obviously saw the raw transcript in L2, but you did a very good job creating an article out of that. I personally hope they concentrate more on making sure F9 and FH are into regular flights, but if they can do landings, great!
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: QuantumG on 10/04/2013 12:17 am
The part that really got me was that it seems SpaceX is actually considering a return to launch site attempt at KSC, in February.

Ya know, 4 months from now.

Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Rangers75 on 10/04/2013 01:06 am
He's probably going to have failures. But at least he's trying. I think we really need an Elon.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: oiorionsbelt on 10/04/2013 01:28 am
The part that really got me was that it seems SpaceX is actually considering a return to launch site attempt at KSC, in February.

Ya know, 4 months from now.


I know, it's great that they are pushing ahead post haste.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: SpaceX David on 10/04/2013 02:14 am
Very good coverage again. Have been reading here for some time. Very no nonsense coverage that is appreciated by most.

You don't really get to know what a site intends with its coverage, because media tend to look for the negatives, but this site appears to be supportive, without pandering. I like that.

And when the managing editor posts the following during the first few seconds of launch....

GO ON GET UP THERE.

You know the intent is positive.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: go4mars on 10/04/2013 02:24 am
considering a return to launch site attempt at KSC, Ya know, 4 months from now.
For the last few years people on this site have said, "Look at the manifest.  I think this next year will be a big one where they..."   Well, these have been impressive years by other metrics, but 2014 and 2015...   I have high expectations.  I feel about SpaceX today about how I felt about Tesla when I bought $17 shares.  For different reasons, but my conviction feels familiar.  Though I'm way more interested in SpaceX.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Jason A on 10/04/2013 03:21 am
Fascinating read, but is it really worth it to go for reusability of stages, when SpaceX have shown they can mass produce them?

I wonder how they balance potential customers for full use of F9 v1.1, versus dropping capability so they can get the stages back?

If it was a good idea, why have no other companies pressed on with it? Such as Arianespace, etc?
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: QuantumG on 10/04/2013 03:29 am
I think you're asking good questions, but I don't think they're relevant to SpaceX.

They want reusability, so they're pursuing it.

That's the power of owning your own company.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: joek on 10/04/2013 03:34 am
The part that really got me was that it seems SpaceX is actually considering a return to launch site attempt at KSC, in February.

Ya know, 4 months from now.

Yeah, I did a triple-take on that.  Won't bet against it, but ... ummm ... wow ... really!?  Even a return-closer-to-launch-site (e.g., a few miles off the CCAFS coast) would be a giant step forward.  In any case, congratulations and best of luck SpaceX.

Thanks QG for the transcript and to all who helped.  Great job with the article Yves.  That should provide plenty of fuel for the speculative fires during the intervening months.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: rickl on 10/04/2013 03:42 am
I'm not sure whether I should post this here or in a discussion thread, but here goes:


From what I have read, the turnaround maneuver and the three-engine retrograde burn were successful, and the first stage re-entered the atmosphere intact.  They even managed to restart the center engine for the landing, before the roll got out of hand.


That sounds like they almost pulled off a soft landing in the ocean on the very first attempt, which is nothing short of astonishing.  I pretty much expected that the vehicle would break up during the high-speed part of the flight, and it would take several attempts to get through that portion of the recovery.


But it sounds like all they have to do is figure out a way to overcome the roll, and they've got it.


That suggests that they may not even need Grasshopper 2.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: yg1968 on 10/04/2013 03:43 am
Fascinating read, but is it really worth it to go for reusability of stages, when SpaceX have shown they can mass produce them?

I wonder how they balance potential customers for full use of F9 v1.1, versus dropping capability so they can get the stages back?

If it was a good idea, why have no other companies pressed on with it? Such as Arianespace, etc?

Re-usability of the first stage is only worth it if you launch often enough. From what I recall, if you launch about once a month, it becomes worth it. Blue Origin is also pursuing re-usability and their intent is to launch once a month.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: CardBoardBoxProcessor on 10/04/2013 03:53 am
but Blue Origin is quite far behind in the game and much slower at said game. No? Though their BE-3 is pretty nice :)

I ponder is this stage ultimately crashing the same as BO's test article being terminated? Though I suppose that would only be comparable to GH2 being terminated. And the fact that they had a Mach 1 Test before GH2 means they might not be slow as the game after all no?

But anyway February for landing on land eh? pretty snazzy.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Elmar Moelzer on 10/04/2013 03:55 am
Excellent article and great news there! I really hope they pull it off. It would be fantastic to see the F9R first stage land successfully already 4 months from now!
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Kabloona on 10/04/2013 03:58 am

That suggests that they may not even need Grasshopper 2.

Just speculating, but Air Force Range Safety and/or FAA may want GH2 demo(s) of a flight-like re-entry/landing before they approve an F9R return to pad attempt. I'd be surprised if they didn't.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: yg1968 on 10/04/2013 04:27 am
but Blue Origin is quite far behind in the game and much slower at said game. No? Though their BE-3 is pretty nice :)

I ponder is this stage ultimately crashing the same as BO's test article being terminated? Though I suppose that would only be comparable to GH2 being terminated. And the fact that they had a Mach 1 Test before GH2 means they might not be slow as the game after all no?

But anyway February for landing on land eh? pretty snazzy.

Blue Origin is aiming for 2018. But I was just trying to make the point that you don't need to fly every day for reuse of the first stage to be worth it. Both Blue Origin and SpaceX seem to believe that.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: spectre9 on 10/04/2013 06:03 am
Incredible step towards reuse.

Seems like confidence with engine restarts has gone up now.

Will be interesting to see when they put the landing legs on.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: daveklingler on 10/04/2013 06:08 am
While it sounds as if their first attempt worked better than most would have dared hope, there could be years of engineering roadblocks still to be overcome. 

They haven't yet launched a first stage with the legged configuration, nor would they be likely to have a final leg design by now.  A leg configuration capable of being reliable in all phases of flight will likely require quite a bit of further refinement and testing.

Once the leg configuration is finalized, there may still be slosh (or other unforeseen) problems.

Once those problems are solved, they may run into fatigue problems with reusing a first stage that's otherwise successfully landed and appears to be ready to go.  The legs and body of the stage will have been to hell and back.  Flight recertification may turn out to be a nasty and expensive task.

I'm cautiously optimistic that SpaceX is capable of coming up with a reusable first stage.  Whether it's worth reusing may turn out to be in doubt.

Sorry, just thought I'd throw out a little doom and gloom to temper the happy optimism.  May the issues turn out to be minor ones!  :)
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: guckyfan on 10/04/2013 06:33 am
I would like to point out this part of the article and of Elons statemen.

Quote
Recovery of the first stage of the Falcon 9 involves a supersonic retro-propulsion with three engines

Supersonic retropropulsion was achieved with the Cassiope flight. That was declared as one of the long poles for propulsive landing on Mars and as a major obstacle for landing large payloads.

I am a little surprised this has not been discussed yet. I mention it here because it is in the article. Any discussion should probably get into another thread.

Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: guckyfan on 10/04/2013 06:37 am

........... I was just trying to make the point that you don't need to fly every day for reuse of the first stage to be worth it. Both Blue Origin and SpaceX seem to believe that.

The assumption of needing a very high flightrate was always based on the assumption that a reusable system would be much more expensive than a disposable one. Since that is not true for Falcon 9 less flights are needed.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Mader Levap on 10/04/2013 08:16 am
While I can believe they could try landing on land in Febuary 2014, result is not certain. And I do not believe they will reuse first stage in 2014, even without counting in usual SpaceX time factor.

I expect first few recovered stages taken apart to last screw by engineers and analyzed to death. These first few never will fly again. One will land in museum, other on SpaceX lawn. Best these can count on is being GH2 spare or something.

And I think that they will discover they need F9 v1.2 before being able to routinely reuse stages. Such is life of former internet entrepreneur that tries to make rockets Silicon Valley way. Considering current tally - six for six - it seems to work out well.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: R7 on 10/04/2013 09:01 am
Quote from: the article
SpaceX still managed to recover portions of the first stage which includes according to preliminary reports, the inter-stage, a number of the components from the engine bay, and some of the composite overwrap pressure vessels.

...

“We have all the pieces necessary to achieve a full recovery of the boost stage.”

Oh Elon you MacGyver you  ;)
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: woods170 on 10/04/2013 09:36 am
The part that really got me was that it seems SpaceX is actually considering a return to launch site attempt at KSC, in February.

Ya know, 4 months from now.


My uneducated guess is that it will be another attempt to perform a water landing.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: MP99 on 10/04/2013 09:42 am
I expect first few recovered stages taken apart to last screw by engineers and analyzed to death. These first few never will fly again. One will land in museum, other on SpaceX lawn. Best these can count on is being GH2 spare or something.

Agree.

Cheers, Martin
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Garrett on 10/04/2013 10:09 am
The part that really got me was that it seems SpaceX is actually considering a return to launch site attempt at KSC, in February.
Ya know, 4 months from now.
My uneducated guess is that it will be another attempt to perform a water landing.
We all expect that it will turn out to be a water landing. What QG is amazed at is that SpaceX appears to have a lot of work (mainly regulatory) done for a return-to-launch-site landing and are actively pursuing such an option for CRS-3. None of us expect all the pieces of the puzzle to come together by February, but it looks like they're gonna come pretty close! That, quite frankly, would be mindblowing.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: rickl on 10/04/2013 11:58 am
My uneducated guess is that it will be another attempt to perform a water landing.
We all expect that it will turn out to be a water landing.
How about a return to the vicinity of the Cape and a water landing just off the coast, where it can be viewed?
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Hop_David on 10/04/2013 12:55 pm
Even a return-closer-to-launch-site (e.g., a few miles off the CCAFS coast)

A botched vertical landing into the ocean wouldn't do too much damage.

A botched vertical landing on land is another story. A worst case scenario is the booster stage striking a populated area at terminal velocity.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: manboy on 10/04/2013 01:02 pm
Super work by by Yves-A. Grondin:

http://www.nasaspaceflight.com/2013/10/musk-plans-reusability-falcon-9-rocket/

We've also released the audio and transcript out of from the post-launch presser:
http://forum.nasaspaceflight.com/index.php?topic=32719.msg1105469#msg1105469

 :) :) :)
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: CuddlyRocket on 10/04/2013 01:21 pm
... I do not believe they will reuse first stage in 2014, even without counting in usual SpaceX time factor.

I expect first few recovered stages taken apart to last screw by engineers and analyzed to death. These first few never will fly again.

Agreed that the first one or two 1st stages recovered will be pored over by the engineers; after all it will be the first chance to do so in history! After that though, I'd simply launch the next one recovered with a dummy 2nd stage. No inspection or refurbishment; just launch-recover, launch-recover, launch-recover until something breaks! This gives you a good idea of the basic reliability of the rocket in re-use. Then I'd introduce a simple inspection regime fixing stuff that's obviously damaged or broken, and see what difference that makes. And iterate.

Not that expensive a testing program. The 1st stage is already paid for by a customer; propellant is a few $100k, and a bit more for a dummy 2nd stage; and most of the needed personnel are being paid anyway!

The first in-mission re-use of a 1st stage? My money is on the Dragon flight abort test. After all, if anything goes wrong it's a good test of the LAS! Sure, if anything did go wrong you'd have to re-do the abort test, but there'll be another recovered 1st stage available for that!
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Orbiter on 10/04/2013 01:23 pm
My uneducated guess is that it will be another attempt to perform a water landing.
We all expect that it will turn out to be a water landing.
How about a return to the vicinity of the Cape and a water landing just off the coast, where it can be viewed?

If they're really trying to return it to the eastern tip of the Cape, I'd imagine Jetty Park or Port Canaveral would be fine to watch that.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Garrett on 10/04/2013 01:23 pm
Even a return-closer-to-launch-site (e.g., a few miles off the CCAFS coast)
[snip]
A worst case scenario is the booster stage striking a populated area at terminal velocity.
That can probably be mitigated quite easily by careful calculation and positioning of the landing/debris ellipses (3-sigma) for all stages of boost back. I think Elon mentioned something along those lines in his recent statements.

Maybe I'm wrong, but I think an explosion on the pad at launch with a fully fueled rocket will probably remain the worst case scenario (population-wise).
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Garrett on 10/04/2013 01:59 pm
Just thought I'd throw this out there, though presumably something like it has already been posted elsewhere. It's a speculative, first-order, return-to-launch-site flight path of an F9R first stage. The path is roughly aligned to an ISS inclination and I think staging occurs around 70km downrange, so that's why I put a green dot at that point.
After staging, the core will continue to gain height and move further down range even during the initial boost back burn.
The eastern tip of the Cape is then the likely landing pad, going on Elon's comments.

The actual ground path will probably have more curved features and S-like bends
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Garrett on 10/04/2013 02:08 pm
In fact, it is not even necessary to return the first stage to launch site, because transporting it from landing site back to processing facility by barge or whatever is almost always cheaper than an additional 15% up-mass penalty. ;)
You can get around the safety problem by landing the booster on land, down range and on an isolated island pad. Islands are pretty easy to aim at using radar area correlation with stored digital map because its altitude should stand out when compared with an essential flat ocean surface.
What islands? You mean an artificial sea platform?
Though I tend to agree, SpaceX (i.e. Elon) has already made it pretty clear that F9R first stages will be boosted back to the launch site (or thereabouts). FH-R first stages, however, will (again according to Elon) likely do what you just said.

Also, an artificial sea platform for a F9 core will probably not be trivial to build. I'll let the experts here let us know how easy/difficult it would be.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: meekGee on 10/04/2013 02:30 pm
In fact, it is not even necessary to return the first stage to launch site, because transporting it from landing site back to processing facility by barge or whatever is almost always cheaper than an additional 15% up-mass penalty. ;)

I think that's true using current launch prices, but less so when considering a much cheaper launch.

If 15% becomes a critical mission enabler, I still say - land down range and fly back.   Or, better, use a bigger rocket.

---

I'm imagining watching a returning stage - there will be a moment where everyone is pushing their eyeballs into the binoculars, searching for the first glimpse of the (inert) free-falling rocket...   What a moment that is - because in just a few seconds, there will be either a plume or an explosion...  :)
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: go4mars on 10/04/2013 02:50 pm
Grasshopper 2 will probably still be needed.  It can demonstrate very fast turnaround and test test test...
There might also be tests related to lunar landings.

Supersonic retropropulsion has been demonstrated now, but how fast was it going?  aerocapture at Mars prior to landing?  Or direct injection?           

I sure hope Elon or Kimbal had a steady hand on their video camera when they flew out to watch!  I'm assuming they were both in there, but don't know.  I know they might wait to release the final moments for their "bloopers reel" a few years from now, but I hope we get to see everything at least up almost until the point of the splash(es). 
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: simonbp on 10/04/2013 03:03 pm
I would like to point out this part of the article and of Elons statemen.

Quote
Recovery of the first stage of the Falcon 9 involves a supersonic retro-propulsion with three engines

Supersonic retropropulsion was achieved with the Cassiope flight. That was declared as one of the long poles for propulsive landing on Mars and as a major obstacle for landing large payloads.

I am a little surprised this has not been discussed yet. I mention it here because it is in the article. Any discussion should probably get into another thread.

Yes, ditto.

I recall being at presentation at JPL where Rob Manning went on about an hour about how you could never do supersonic retropropulsion, and thus Mars landers will always need parachutes to get from Mach 3-4 to subsonic. If SpaceX got this working, then landing on Mars just became a whole lot easier.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: rst on 10/04/2013 03:07 pm
Also, an artificial sea platform for a F9 core will probably not be trivial to build. I'll let the experts here let us know how easy/difficult it would be.

I'm not sure there are experts anywhere on building seagoing landing pads for descending rocket stages.  That said, one obvious comparable technology is semi-submersible oil drilling platforms.  When deployed, the above-water structure of these rests on partially flooded hulls that wind up at rest well below the surface; this makes them more or less level whatever the surface waves are doing.

Looking around for prices on these, the cost of a new one was a bit under $400 million several years ago: http://www.scandoil.com/moxie-bm2/news/keppel-wins-us385-million-semisubmersible-rig-cont.shtml (http://www.scandoil.com/moxie-bm2/news/keppel-wins-us385-million-semisubmersible-rig-cont.shtml), though a substantial fraction of that (perhaps most?) was probably for drilling equipment.  However, Elon's style would probably be to go look for a cheap one secondhand first, if there were any available.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Kabloona on 10/04/2013 03:31 pm

I sure hope Elon or Kimbal had a steady hand on their video camera when they flew out to watch!  I'm assuming they were both in there, but don't know. 


Elon seemed to imply the video was being returned by boat, which is why it would take a week or so to get back to corporate HQ and be posted. Probably the video was shot on board one of the recovery boats.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: neviden on 10/04/2013 03:43 pm
I think that it he will try for a land in february, if he can build it by then and get FAA to say "ok". The worst it would happen is that RSO would have to destroy it in the air over the ocean or that it crashes an empty stage on a simple concrete pad in the middle of nowhere.

As far as a longterm falcon future it is VERY bright. I am quite certain that many in NASA would love nothing more then to say to Musk "please take our 15 $B and do whatever you would like to do..". Can anyone imagine what would that do to spaceflight? You know, those good ideas that we can read in dusty old pdfs? That would no longer be "it costs 500 $B and will take 30 years to complete" but someting that would be built. 200 mt reusable, cheap flights. Depos. SEP. Nautilus-X spaceships. Mars. Moon. Phobos. 2001 style spacestations. Asteroid habitats,..

But, what probably will happen is that SpaceX will get to have 4 pads, lots of "pork free" profit from GEO, DoD, NASA and Biggelow LEO launches. Musk will then take this money, build his Falcon X, Mars missions and go to Mars just so he can take a picture of green plants on a red Mars in person. Then, he will put that on the wall and ask himself "hmm.. What should I do next?" :)
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: BrightLight on 10/04/2013 03:55 pm
Grasshopper 2 will probably still be needed.  It can demonstrate very fast turnaround and test test test...
There might also be tests related to lunar landings.

Supersonic retropropulsion has been demonstrated now, but how fast was it going?  aerocapture at Mars prior to landing?  Or direct injection?           

I sure hope Elon or Kimbal had a steady hand on their video camera when they flew out to watch!  I'm assuming they were both in there, but don't know.  I know they might wait to release the final moments for their "bloopers reel" a few years from now, but I hope we get to see everything at least up almost until the point of the splash(es).
I think a new thread should be opened on super sonic retro-propulsion, i for one would be very interested in the details - fuel consumption, deceleration rates, TPS heating rates, ablation rates etc.
Amazing stuff.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: douglas100 on 10/04/2013 03:58 pm
I would like to point out this part of the article and of Elons statemen.

Quote
Recovery of the first stage of the Falcon 9 involves a supersonic retro-propulsion with three engines

Supersonic retropropulsion was achieved with the Cassiope flight. That was declared as one of the long poles for propulsive landing on Mars and as a major obstacle for landing large payloads.

I am a little surprised this has not been discussed yet. I mention it here because it is in the article. Any discussion should probably get into another thread.

Yes, ditto.

I recall being at presentation at JPL where Rob Manning went on about an hour about how you could never do supersonic retropropulsion, and thus Mars landers will always need parachutes to get from Mach 3-4 to subsonic. If SpaceX got this working, then landing on Mars just became a whole lot easier.

I think the SpaceX maneuver may not be exactly equivalent to a Mars landing burn. It depends under what conditions the F9 engines were restarted. Did it it happen when they were still effectively in a vacuum, or was the vehicle already in the atmosphere and being subjected to a supersonic air stream? My understanding of the Mars landing maneuver was that the landing burn had to be started in the atmosphere against the supersonic flow and that was what made the whole thing difficult.

The final burn of the F9 was definitely started against the airflow, but by that time the vehicle would be subsonic.

Edit: @ Bright Light: I think you might be right.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Eric Hedman on 10/04/2013 04:15 pm
Grasshopper 2 will probably still be needed.  It can demonstrate very fast turnaround and test test test...
There might also be tests related to lunar landings.

Supersonic retropropulsion has been demonstrated now, but how fast was it going?  aerocapture at Mars prior to landing?  Or direct injection?           

I sure hope Elon or Kimbal had a steady hand on their video camera when they flew out to watch!  I'm assuming they were both in there, but don't know.  I know they might wait to release the final moments for their "bloopers reel" a few years from now, but I hope we get to see everything at least up almost until the point of the splash(es).
I think a new thread should be opened on super sonic retro-propulsion, i for one would be very interested in the details - fuel consumption, deceleration rates, TPS heating rates, ablation rates etc.
Amazing stuff.
Here is a youtube video of one of Langley's supersonic retropropulsion wind tunnel tests.

http://www.youtube.com/watch?v=i-coJg_vgxI (http://www.youtube.com/watch?v=i-coJg_vgxI)
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: douglas100 on 10/04/2013 04:16 pm
Also, an artificial sea platform for a F9 core will probably not be trivial to build. I'll let the experts here let us know how easy/difficult it would be.

I'm not sure there are experts anywhere on building seagoing landing pads for descending rocket stages...

This has been discussed over and over again on other threads. For F9 (not F9H) there is no indication that they intend to  land stages downrange operationally. The point is to keep the operational cost as low as possible at the expense of taking a payload hit of about 30%. And that means they have to spend precisely nothing on downrange recovery. They are not trying to squeeze every last drop of performance out of the system.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: dcporter on 10/04/2013 04:43 pm
Here's a link to 17 pages of downrange / ocean landing discussion. Please read it through and continue discussion there.

http://forum.nasaspaceflight.com/index.php?topic=31452.0
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Robotbeat on 10/04/2013 05:26 pm
I would like to point out this part of the article and of Elons statemen.

Quote
Recovery of the first stage of the Falcon 9 involves a supersonic retro-propulsion with three engines

Supersonic retropropulsion was achieved with the Cassiope flight. That was declared as one of the long poles for propulsive landing on Mars and as a major obstacle for landing large payloads.

I am a little surprised this has not been discussed yet. I mention it here because it is in the article. Any discussion should probably get into another thread.

Yes, ditto.

I recall being at presentation at JPL where Rob Manning went on about an hour about how you could never do supersonic retropropulsion, and thus Mars landers will always need parachutes to get from Mach 3-4 to subsonic. If SpaceX got this working, then landing on Mars just became a whole lot easier.
Where does Rob Manning say that? It sounds obviously wrong. The whole problem of supersonic retropropulsion is pretty much limited to the case of a single engine in the center of the heatshield (you're pretty much fine if you use multiple engines more towards the sides), and even there, much of the issue is just a reduction of drag once you fire up the engine.

This sounds like one of those things that people hear is sort of a problem because of some study, but then they never return to examine what the assumptions of the problem actually are before saying the whole concept is worthless. This seems to happen far more often when someone has a stake in the concept /not/ working.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: JBF on 10/04/2013 05:31 pm
The whole problem of supersonic retropropulsion is pretty much limited to the case of a single engine in the center of the heatshield (you're pretty much fine if you use multiple engines more towards the sides), and even there, much of the issue is just a reduction of drag once you fire up the engine.

Are you sure about that?  Watching Langley's supersonic retropropulsion wind tunnel tests it looks like 1 in the center is the more stable air flow.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Robotbeat on 10/04/2013 05:36 pm
The whole problem of supersonic retropropulsion is pretty much limited to the case of a single engine in the center of the heatshield (you're pretty much fine if you use multiple engines more towards the sides), and even there, much of the issue is just a reduction of drag once you fire up the engine.

Are you sure about that?  Watching Langley's supersonic retropropulsion wind tunnel tests it looks like 1 in the center is the more stable air flow.
The nozzles are still very close to the center.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: VatTas on 10/04/2013 06:17 pm
One piece of information that I'm actually missing is how close to target area was first stage when it ignited (and flamed out). But since SpaceX looks happy with results, one could speculate that it was not very far-off.

Update: ok, I read the transcript, Elon states that "We controlled the stage with a fair bit of precision to a landing point with the center engine burn".
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Jarnis on 10/04/2013 07:33 pm
One piece of information that I'm actually missing is how close to target area was first stage when it ignited (and flamed out). But since SpaceX looks happy with results, one could speculate that it was not very far-off.

Update: ok, I read the transcript, Elon states that "We controlled the stage with a fair bit of precision to a landing point with the center engine burn".

Just wish Mr. Musk would get that video uploaded to somewhere already. Been checking SpaceX youtube and vimeo accounts daily...  ;D
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: PreferToLurk on 10/04/2013 08:19 pm
One piece of information that I'm actually missing is how close to target area was first stage when it ignited (and flamed out). But since SpaceX looks happy with results, one could speculate that it was not very far-off.

Update: ok, I read the transcript, Elon states that "We controlled the stage with a fair bit of precision to a landing point with the center engine burn".

Just wish Mr. Musk would get that video uploaded to somewhere already. Been checking SpaceX youtube and vimeo accounts daily...  ;D

He has a history of over committing his PR team.  The 3D design and printing video took longer than promised also.  I have my money on next Tuesday.

But yeah, this has to be one of the most anticipated SpaceX videos since the first hoverslam!
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: mlindner on 10/05/2013 03:24 am

I sure hope Elon or Kimbal had a steady hand on their video camera when they flew out to watch!  I'm assuming they were both in there, but don't know. 


Elon seemed to imply the video was being returned by boat, which is why it would take a week or so to get back to corporate HQ and be posted. Probably the video was shot on board one of the recovery boats.

False, talked to a friend the day after launch who described the video as being awesome. He's not a high ranking engineer either so the video has been widely circulated internal to SpaceX.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: mlindner on 10/05/2013 03:30 am
Grasshopper 2 will probably still be needed.  It can demonstrate very fast turnaround and test test test...
There might also be tests related to lunar landings.

Supersonic retropropulsion has been demonstrated now, but how fast was it going?  aerocapture at Mars prior to landing?  Or direct injection?           

I sure hope Elon or Kimbal had a steady hand on their video camera when they flew out to watch!  I'm assuming they were both in there, but don't know.  I know they might wait to release the final moments for their "bloopers reel" a few years from now, but I hope we get to see everything at least up almost until the point of the splash(es).
I think a new thread should be opened on super sonic retro-propulsion, i for one would be very interested in the details - fuel consumption, deceleration rates, TPS heating rates, ablation rates etc.
Amazing stuff.

Stop posting about creating one, and create one.
Done and done. Go talk about it.

http://forum.nasaspaceflight.com/index.php?topic=33006.0
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: guckyfan on 10/05/2013 03:32 am
I understand the video is from an onboard camera and the recording was recovered from the materials salvaged, probably the interstage. I really expect awesome pictures.

Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: mlindner on 10/05/2013 03:41 am
I understand the video is from an onboard camera and the recording was recovered from the materials salvaged, probably the interstage. I really expect awesome pictures.

He saw the video before the boat got back to the dock... Nobody uses film canisters anymore. It was probably received by a telemetry boat or some other method and beamed directly back to SpaceX HQX.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: guckyfan on 10/05/2013 03:46 am

He saw the video before the boat got back to the dock... Nobody uses film canisters anymore. It was probably received by a telemetry boat or some other method and beamed directly back to SpaceX HQX.

Did he state he saw it? I don't expect a film canister. Digital recording devices are available. And I am sure it was mentioned the video comes back with the boat.

Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: mlindner on 10/05/2013 05:17 am

He saw the video before the boat got back to the dock... Nobody uses film canisters anymore. It was probably received by a telemetry boat or some other method and beamed directly back to SpaceX HQX.

Did he state he saw it? I don't expect a film canister. Digital recording devices are available. And I am sure it was mentioned the video comes back with the boat.

Yes he saw it, gave his impressions of it.

Source of knowing it comes back with the boat?
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: guckyfan on 10/05/2013 06:13 am
Yes he saw it, gave his impressions of it.

Source of knowing it comes back with the boat?

As I said from memory it was given as reason for the late release. Also saying it is a cool video does not require him to have seen it. Knowing it is from one or more onboard cameras is enough to make that statement.

But again this ia my interpretation of what was said, I don't state it as a fact.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: ugordan on 10/05/2013 01:45 pm
Anyone want to speculate on the location of the 1st stage camera?
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Kabloona on 10/05/2013 02:40 pm
Anyone want to speculate on the location of the 1st stage camera?

Looks like you nailed it. And was it you or someone else who identified the bump to the right of the words "2nd stage" as an ACS thruster cluster?

Edit: here's the other photo, from corrodednut. Presumably this is the other side of the rocket showing the thruster cluster at 180 degrees opposite:

http://forum.nasaspaceflight.com/index.php?topic=32859.msg1103849#msg1103849
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: corrodedNut on 10/07/2013 04:56 pm
Anyone want to speculate on the location of the 1st stage camera?

Seems that they moved the 2nd stage camera around to the other side, whereas before it was on the erector-side, looking down at the combo umbilical disconnect.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: ugordan on 10/07/2013 05:09 pm
My guess is that stuff spraying from the disconnect during staging had something to do with the relocation to the other side.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lobo on 10/07/2013 06:23 pm
The eastern tip of the Cape is then the likely landing pad, going on Elon's comments.


I just ran into this on Wikipedia:

http://en.wikipedia.org/wiki/Spaceport_Florida_Launch_Complex_46

"As of September 2013[update], SLC-46 is being considered by SpaceX as a landing site for the reusable first stages of their Falcon 9 rocket.[5]"

Which -is- right out on the eastern tip of the Cape.

Makes sense, Spaceport Florida gets a customer for that complex, and it's in a good location, and away from active launch complex.  And if it's coming back in off course they can just abort and ditch in the ocean.  I'd guess there might be some boat traffic restriction on launch days so an aborted Falcon core doesn't come falling out of the sky on a cruise ship or something?



Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lar on 10/07/2013 06:26 pm
The eastern tip of the Cape is then the likely landing pad, going on Elon's comments.


I just ran into this on Wikipedia:

http://en.wikipedia.org/wiki/Spaceport_Florida_Launch_Complex_46

"As of September 2013[update], SLC-46 is being considered by SpaceX as a landing site for the reusable first stages of their Falcon 9 rocket.[5]"

Did you check the reference? That tidbit is referenced back here to NSF! :) Specifically this post :
     http://forum.nasaspaceflight.com/index.php?topic=32946.msg1103282#msg1103282
which in turn has a ref back to the WP article. Snakes swallowing each others tails at its finest! :)
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lobo on 10/07/2013 06:40 pm
Did you check the reference? That tidbit is referenced back here to NSF! :)

Ha!  No I didn't.  That's funny.

Well, apparently didn't know it'd already been discussed here.  :-)

But, I was thinking LC-36 or 46 even before I ran accross that.   46 works good because it's out there farther on the Cape.
And if for some reason SpaceX can get use of pad LC-39A, then LC-36 could  be a good alternative.  Although it'd require more work.  It'd be nice and close to LC-46 too. 
Although I think they might be look at the Shiloh area as an alternate to LC-36.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lobo on 10/07/2013 07:36 pm
On a similar note.  Where would a reusable FH launching from VAFB fly back too?  Could they set something up at SLC-4W and just bring them back in right next to their launch complex?
Can they do that to dogleg trajectories to the ISS or something?  The extra performance of FH should allow F9v1.1 class payload to launch from VAFB to orbits that would traditionally use Cape Canaveral I would think?
And if they can bring all three boosters back to SLC-4 and land them, no more hardware is expended than for a normal F9R single stick reusable launch.  They just move them the short distace to the HIF and process them and join them back together.



Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: douglas100 on 10/07/2013 09:35 pm
On a similar note.  Where would a reusable FH launching from VAFB fly back too?  Could they set something up at SLC-4W and just bring them back in right next to their launch complex?

http://http://thespaceport.us/forum/uploads/monthly_06_2012/post-10859-0-32907800-1340226614_thumb.jpg
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lobo on 10/07/2013 10:49 pm
On a similar note.  Where would a reusable FH launching from VAFB fly back too?  Could they set something up at SLC-4W and just bring them back in right next to their launch complex?

http://http://thespaceport.us/forum/uploads/monthly_06_2012/post-10859-0-32907800-1340226614_thumb.jpg

Ahhh...I was right.  Cool.

Maybe they could take that Titan Tower from SLC-4W, move to to 4E, and modify it for Falcon.  The two pads were the same I think so it should fit right on the rails of the old MSS. 
But...might be easier to just build a new purpose built one.

Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: llanitedave on 10/08/2013 01:36 am
On a similar note.  Where would a reusable FH launching from VAFB fly back too?

The factory roof at Hawthorne?   8)
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lars_J on 10/08/2013 02:39 am
On a similar note.  Where would a reusable FH launching from VAFB fly back too?  Could they set something up at SLC-4W and just bring them back in right next to their launch complex?

http://http://thespaceport.us/forum/uploads/monthly_06_2012/post-10859-0-32907800-1340226614_thumb.jpg

Don't take that too literal - at least initially. The first landing pad in west coast appears to be planned mile or two from LC-40. Somewhere near the eastern tip of CCAFS if I recall right.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lobo on 10/08/2013 05:12 am
On a similar note.  Where would a reusable FH launching from VAFB fly back too?  Could they set something up at SLC-4W and just bring them back in right next to their launch complex?

http://http://thespaceport.us/forum/uploads/monthly_06_2012/post-10859-0-32907800-1340226614_thumb.jpg

Don't take that too literal - at least initially. The first landing pad in west coast appears to be planned mile or two from LC-40. Somewhere near the eastern tip of CCAFS if I recall right.

LC-46?  out on the tip of the Cape?
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lars_J on 10/08/2013 05:56 am
On a similar note.  Where would a reusable FH launching from VAFB fly back too?  Could they set something up at SLC-4W and just bring them back in right next to their launch complex?

http://http://thespaceport.us/forum/uploads/monthly_06_2012/post-10859-0-32907800-1340226614_thumb.jpg

Don't take that too literal - at least initially. The first landing pad in west coast appears to be planned mile or two from LC-40. Somewhere near the eastern tip of CCAFS if I recall right.

LC-46?  out on the tip of the Cape?

Yes, presumably near it. Here is the source, quotes from Elon at the post CASSIOPE press conference: http://shitelonsays.com/transcript/spacex-press-conference-september-29-2013-2013-09-29

Here are the relevant quotes:
Quote
For any landing area that we would have, the landing ellipse, the sort of error that the stage could encounter would be an unpopulated region. So we would aim to have a landing site that's unpopulated with a radius of a couple of miles (which can be achieved in Cape Canaveral and Vandenberg).
...
[Question about landing on land and FAA licensing for landing] We have actually been working with Air Force range safety and the FAA to identify landing locations at Cape Canaveral and we have identified a few. I don't think that we are quite ready to say what those locations are but they are kind of out on the tip of Cape Canaveral, on the eastern most tip of Cape Canaveral. It's great working with both Air Force range safety and the FAA. They have actually been quite supportive of the whole thing. You need a (FAA) license and we expect to get it
.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Zed_Noir on 10/08/2013 11:09 am
On a similar note.  Where would a reusable FH launching from VAFB fly back too?

I jokingly suggest razing SLC-4W and convert it to a landing pad previously. On reflection, it is simpler just poured some new pads closer to the beachfront.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lobo on 10/08/2013 06:55 pm
On a similar note.  Where would a reusable FH launching from VAFB fly back too?

I jokingly suggest razing SLC-4W and convert it to a landing pad previously. On reflection, it is simpler just poured some new pads closer to the beachfront.

There'll probably be some big environmental impact kerfuffle if they get too close to the water if there's not already something there.  Gotta love the times we live in.

They may not have to raze SLC-4W, just put in a big long concrete pad along in front of it (on the ocean side).  Enough so you could land 3 F9 cores if you needed to.  Or demolish the Titan MSS (or move it over to 4E) and then it looks like other than the actual 4W pad and flame trench, there's a pretty big open leveled area already.  That looks like it could be expaded back towards the 4E side to make even larger.   (Just looking at Google Maps.  Standing at the site might big a different impression of what could be done where).
That way they could have all the cranes and equipment right there to go drop the cores onto a transporter and send them right back into the HIV. 

Looking at the picture below, it would seem there'd be a good deal of area there if they removed the MSS and leveled out the area around 4W and extended it to that road there between the two pads.  I can't find a good picture of Google maps of it, but from that it looks like there's a pretty big level area already.  And then could expand that more as necessary.   

I can't imagine there'd be enough launches from VAFB overall to warrant SpaceX wanting to use 4W to launch, but if they leave the actual flame trench there, they would always have that option in the future.  In case that changed some day.
And in reality, if they actually -are- able to proove out reusable first stages and reliably land them back at the launch complex with minmal processing before the next launch, they could actually launch payloads that would normally launch from the East Coast from there on a FH, non-cross-fed, with all three boosters staging at about the same time.  You have to launch with more power, but if you can recover those stages, and the 2nd stage will be expended no matter where you launch from, then why not?  Do the dog-leg ascent.  That could allow them to augment their East Coast capability by differing some payloads to Vandy.


Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: douglas100 on 10/08/2013 07:51 pm

And in reality, if they actually -are- able to prove out reusable first stages and reliably land them back at the launch complex with minimal processing before the next launch, they could actually launch payloads that would normally launch from the East Coast from there on a FH, non-cross-fed, with all three boosters staging at about the same time.  You have to launch with more power, but if you can recover those stages, and the 2nd stage will be expended no matter where you launch from, then why not?  Do the dog-leg ascent.  That could allow them to augment their East Coast capability by differing some payloads to Vandy.

I suppose it would mostly depend on cost. If you're proposing that a payload which would normally go on an F9R from Canaveral could go on an FH from Vandenberg instead, with dog-legging, it probably could (for some orbits.) But at Vandenberg you would have to recover and refurbish three cores as opposed to only one at Canaveral. That makes the Vandenberg option more expensive. How much more expensive depends on the cost of refurbishing landed cores which is unknown at the moment. If the difference were small, it might be worth doing.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lobo on 10/11/2013 12:42 am
On a similar note.  Where would a reusable FH launching from VAFB fly back too?  Could they set something up at SLC-4W and just bring them back in right next to their launch complex?

http://http://thespaceport.us/forum/uploads/monthly_06_2012/post-10859-0-32907800-1340226614_thumb.jpg

On a side note, if they do put some big concrete pads for landing F9 cores at SLC-4W or even down closer to the ocean, any reason they couldn't land Dragon there too?  That would actually then prevent any land flyover and mitigate the change of a Dragon manfunctioning and crashing down on a town or something.  I know they've shown graphics of Edwards AFB for the landing, and likely the first test ones could be there as there's lots and lots of flat ground to practice landing.  But it seems a pad right on the short on the US west coast would be a great place to bring a capsule back to.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: StephenB on 10/11/2013 01:00 am
Wouldn't dragon be coming from the west?
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: llanitedave on 10/11/2013 01:40 am
They could land at Vandenberg.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: baldusi on 10/11/2013 01:59 am
Wouldn't dragon be coming from the west?
SLC-4W is in VAFB.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lobo on 10/11/2013 03:17 am
Wouldn't dragon be coming from the west?
SLC-4W is in VAFB.

Yes I am referring to SpaceX's VAFB culex on the west coast.

Dunno that Edwards would be unsafe per se.  But if they have a facility right on the coast there that's already going to be set up to land vehicles on rocket propulsion seems like it could be actually better than Edwards. 
And they'd be coming in over water right to touchdown so ditching in the ocean is always a backup option right off the coast there.

Seems pretty attractive.  Any reason it wouldn't be I'm not thinking of?
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Garrett on 10/11/2013 08:54 am
Wouldn't dragon be coming from the west?
SLC-4W is in VAFB.
Yes I am referring to SpaceX's VAFB culex on the west coast.
Dunno that Edwards would be unsafe per se.  But if they have a facility right on the coast there that's already going to be set up to land vehicles on rocket propulsion seems like it could be actually better than Edwards. 
And they'd be coming in over water right to touchdown so ditching in the ocean is always a backup option right off the coast there.
Seems pretty attractive.  Any reason it wouldn't be I'm not thinking of?
Dragon, being a capsule, should always reenter completely intact even if all active control is lost. So it should have a very low probability of breaking up like a winged vehicle (e.g. Shuttle orbiter) and therefore have an almost nonexistent debris field. If my reasoning is valid, then a Dragon landing at Edwards would be safe-ish if the touchdown ellipse for an uncontrolled reentry was still within the base, preferably on the dry lakebed. I have no idea what the size of such an ellipse would be. Note, even if all active control is lost, the parachutes would likely still open, and the SuperDraco thrusters may even ignite, allowing for a soft touchdown.

The landing ellipse at VAFB for an uncontrolled Dragon reentry would likely include quite a few launch pads. Not good. Also, if Dragon reentry control is defective, then there'd probably be no control mechanism for "ditching in the ocean".

I've ignored a heatshield defect, which could cause Dragon to breakup.  For what it's worth, Shuttle broke up over an area about 800 miles from Florida. An equivalent distance would be in the Pacific with respect to Edwards. Though a capsule would probably have a completely different break-up profile.

This is prob OT here, and we could bring the discussion to a Dragon thread?
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: llanitedave on 10/12/2013 04:15 am
Wouldn't dragon be coming from the west?
SLC-4W is in VAFB.

Yes I am referring to SpaceX's VAFB culex on the west coast.

Dunno that Edwards would be unsafe per se.  But if they have a facility right on the coast there that's already going to be set up to land vehicles on rocket propulsion seems like it could be actually better than Edwards. 
And they'd be coming in over water right to touchdown so ditching in the ocean is always a backup option right off the coast there.

Seems pretty attractive.  Any reason it wouldn't be I'm not thinking of?

The only problem I can think of is that there are public highways between the actual coast and the VAFB.  I'm assuming they'd have to be closed both for launch and return. 
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Joffan on 10/12/2013 06:22 pm

The only problem I can think of is that there are public highways between the actual coast and the VAFB.  I'm assuming they'd have to be closed both for launch and return. 

A full risk evaluation should result in no highway closures, since the total risk of closing a highway - and the resulting  displacement of traffic onto less suitable roads - would be significantly higher than the vanishingly small risk of debris impact casualties.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: corrodedNut on 10/16/2013 09:13 pm
Anyone want to speculate on the location of the 1st stage camera?

I think this confirms it. The top of the cable tray or trunk is visible in the center, right where it should be in your photo. If the cameras are on the Earth-facing side of the rocket during flight (the 2nd stage camera stays that way), and the 1st stage flips end-over-end after stage-sep, then the 1st stage camera is on "top" of the rocket during the first braking burn. The curve of the Earth matches this orientation.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Jim on 10/16/2013 09:16 pm

The only problem I can think of is that there are public highways between the actual coast and the VAFB.  I'm assuming they'd have to be closed both for launch and return. 

No, there isn't any public roads there.  However, there is a railroad. 
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lar on 10/16/2013 09:41 pm

The only problem I can think of is that there are public highways between the actual coast and the VAFB.  I'm assuming they'd have to be closed both for launch and return. 

A full risk evaluation should result in no highway closures, since the total risk of closing a highway - and the resulting  displacement of traffic onto less suitable roads - would be significantly higher than the vanishingly small risk of debris impact casualties.

I think you might be ignoring "rubberneck" casualties... people startled by something they're not used to seeing coming down at a high rate of speed might cause them to slam on their brakes, veer off, rear end others who slammed on THEIR brakes, etc...

I expect road closures at least for a while. Till this sort of reuse is completely routine and people are blase about it. (think of the warning signs... "caution, rockets landing nearby" :)  )

(I speak of the general case, not the case at Vandy per se)
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: meekGee on 10/16/2013 10:01 pm

The only problem I can think of is that there are public highways between the actual coast and the VAFB.  I'm assuming they'd have to be closed both for launch and return. 

A full risk evaluation should result in no highway closures, since the total risk of closing a highway - and the resulting  displacement of traffic onto less suitable roads - would be significantly higher than the vanishingly small risk of debris impact casualties.

I think you might be ignoring "rubberneck" casualties... people startled by something they're not used to seeing coming down at a high rate of speed might cause them to slam on their brakes, veer off, rear end others who slammed on THEIR brakes, etc...

I expect road closures at least for a while. Till this sort of reuse is completely routine and people are blase about it. (think of the warning signs... "caution, rockets landing nearby" :)  )

(I speak of the general case, not the case at Vandy per se)

Easily solved by a "Rockets Crossing" road sign.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: GalacticIntruder on 10/16/2013 10:49 pm
Is there any reason they cannot land at Shuttle Landing Facility?
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: llanitedave on 10/17/2013 02:44 am

The only problem I can think of is that there are public highways between the actual coast and the VAFB.  I'm assuming they'd have to be closed both for launch and return. 

No, there isn't any public roads there.  However, there is a railroad.

Checking Google Earth, I see Lasalle Canyon Road paralleling the railway, and passing to the west of the Space X facilities.  I see no access control points on that road.  Boosters, however, would be returning from the south, and there appears to be at least the Coast Road as a public highway on the south coast.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: jimvela on 10/17/2013 03:00 am
Is there any reason they cannot land at Shuttle Landing Facility?

The VAFB shuttle landing facility runway is actively used by USAF, and there are a number of facilities adjacent to it (for example the ASO payload processing facility).

Returning SpaceX Falcons are unlikely to ever land there...
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: CardBoardBoxProcessor on 10/17/2013 03:56 am
Honestly the thing I am most curious about is what they plan to do once they land... It takes a TEL to raise it. how will they get them back down in a cheap, quick, rapidly reproducable, and efficent way.  :o
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Jim on 10/17/2013 04:00 am

Checking Google Earth, I see Lasalle Canyon Road paralleling the railway, and passing to the west of the Space X facilities.  I see no access control points on that road.  Boosters, however, would be returning from the south, and there appears to be at least the Coast Road as a public highway on the south coast.

1.  that is Coast road and not LaSalle Canyon road
2.  The next one is Surf road
Neither are public.  there are no access control points because the whole base is closed.  The road is closed at the Amtrak station.
3
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: guckyfan on 10/17/2013 04:05 am
Honestly the thing I am most curious about is what they plan to do once they land... It takes a TEL to raise it. how will they get them back down in a cheap, quick, rapidly reproducable, and efficent way.  :o

They handle the first stage with a crane at McGregor, putting it up on the tripod for testing. They can do that with the landed stage too, at least after residual fuel has been taken out.



Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Helodriver on 10/17/2013 04:56 am
An informed rumor at Vandenberg is pointing to this spot.

http://goo.gl/maps/U83SE (http://goo.gl/maps/U83SE)

Originally built as a parking and turning pad for trailers bearing barge delivered Space Shuttle External Fuel tanks. The concrete is in need of resurfacing currently, but it would allow returns from the south over the ocean without overflight of other critical facilities and it affords good ground handling access.

The runway, mentioned above, at this time has very little use and ample space. Scheduling conflicts could be easily managed. Inbound trajectories would involve more overflight of other infrastructure.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Linze on 10/17/2013 05:20 am
An informed rumor at Vandenberg is pointing to this spot.

http://goo.gl/maps/U83SE (http://goo.gl/maps/U83SE)

Is the port a few hundred meters to the east still active?
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Helodriver on 10/17/2013 05:48 am
Yes, ULA's Delta Mariner ship docks there to offload Delta IV and Atlas V components.

Its also a good fishing and diving spot  ;)
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: llanitedave on 10/17/2013 06:21 am

Checking Google Earth, I see Lasalle Canyon Road paralleling the railway, and passing to the west of the Space X facilities.  I see no access control points on that road.  Boosters, however, would be returning from the south, and there appears to be at least the Coast Road as a public highway on the south coast.

1.  that is Coast road and not LaSalle Canyon road
2.  The next one is Surf road
Neither are public.  there are no access control points because the whole base is closed.  The road is closed at the Amtrak station.
3

OK, I understand that Google and other maps often mislabel roads, so no reason for me to disagree here.  And I did see the Amtrak station, but I didn't see anything resembling a gate or guard station near that intersection, nor did there seem to be one on the south side of coast road.

Helodriver's pointing out of the pad south of Coast Road is pretty intriguing too.  If true, it seems like an ideal spot.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: corrodedNut on 10/17/2013 11:35 am
An informed rumor at Vandenberg is pointing to this spot.

http://goo.gl/maps/U83SE (http://goo.gl/maps/U83SE)

Originally built as a parking and turning pad for trailers bearing barge delivered Space Shuttle External Fuel tanks. The concrete is in need of resurfacing currently, but it would allow returns from the south over the ocean without overflight of other critical facilities and it affords good ground handling access.

The runway, mentioned above, at this time has very little use and ample space. Scheduling conflicts could be easily managed. Inbound trajectories would involve more overflight of other infrastructure.

By my calculations, the major area of this "landing pad" is a circle roughly 135ft/41m in diameter, not including the adjacent road surface.

For comparison, the Grasshopper pad in McGregor is 150ft/46m square.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Jim on 10/17/2013 12:25 pm

OK, I understand that Google and other maps often mislabel roads, so no reason for me to disagree here.  And I did see the Amtrak station, but I didn't see anything resembling a gate or guard station near that intersection, nor did there seem to be one on the south side of coast road.


Go to street view and you will see that road is blocked off south of the station.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Sohl on 10/17/2013 05:03 pm
Easily solved by a "Rockets Crossing" road sign.

What, like this?   ;D

Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: meekGee on 10/17/2013 06:15 pm
Easily solved by a "Rockets Crossing" road sign.

What, like this?   ;D

'sactly... :)
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lar on 10/17/2013 06:45 pm
Nice 'shop job...

I want to see a real one, some day not too far off :)
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Mongo62 on 10/17/2013 06:54 pm
An informed rumor at Vandenberg is pointing to this spot.

http://goo.gl/maps/U83SE (http://goo.gl/maps/U83SE)

Originally built as a parking and turning pad for trailers bearing barge delivered Space Shuttle External Fuel tanks. The concrete is in need of resurfacing currently, but it would allow returns from the south over the ocean without overflight of other critical facilities and it affords good ground handling access.

The runway, mentioned above, at this time has very little use and ample space. Scheduling conflicts could be easily managed. Inbound trajectories would involve more overflight of other infrastructure.

If this location is chosen, I would expect some absolutely spectacular aerial shots of returning first stages in the future. You could not ask for a more impressive setting.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lobo on 10/17/2013 07:45 pm
An informed rumor at Vandenberg is pointing to this spot.

http://goo.gl/maps/U83SE (http://goo.gl/maps/U83SE)

Originally built as a parking and turning pad for trailers bearing barge delivered Space Shuttle External Fuel tanks. The concrete is in need of resurfacing currently, but it would allow returns from the south over the ocean without overflight of other critical facilities and it affords good ground handling access.

The runway, mentioned above, at this time has very little use and ample space. Scheduling conflicts could be easily managed. Inbound trajectories would involve more overflight of other infrastructure.

If this location is chosen, I would expect some absolutely spectacular aerial shots of returning first stages in the future. You could not ask for a more impressive setting.

Cool.  That does seem like a pretty ideal location.  A water-only approach, nothing else there, no infrastructure flyovers.  And then have cranes staged nearby that can lower the cores onto trucks and truck them back to SLC-4 for refurb and remating.

They'd want to expand the concete enough to make a tarmack out of it large enough to bring in three F9R cores at once though, for a non-crossfed FH, with all cores burning out at nearly the same time.  Worse case landing scenario.  Although I'd expect to see that configuration fly a lot to be honest, because it should give enough performance to duplicate a fully expendable F9R capacity LV, and that will probably be their bread and butter payload range. Maybe enough to duplicate an F9R launching from the Cape, in which case the VAFB launching location might get a lot more use than it otherwise would have, as orbits that need the West Coast launch site aren't that frequent I don't think.
And SpaceX is still only expending the upper stage, same as a single stick F9R reusing the booster.   So why not fly the FH version, take the performance hit when you have the margin to spare, and fly payloads from FAFB that would otherwise fly from the Cape?  Like COTS missions?  I wonder how much payload a non crossfed reusable FH could put into a standard GTO or GSO orbit from VAFB on a dog-leg trajectory?  Or how much to the ISS?


Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lars_J on 10/17/2013 07:52 pm
I'm not sure ULA would appreciate the landing site being so close to SLC-6, nor its crucial part access road for the Delta IV deliveries.

This abandoned pad at the end of Spur Rd seems like a much better option. Very close to the ocean, and not so close to other active pads:
https://www.google.com/maps/preview#!data=!1m4!1m3!1d2917!2d-120.6191027!3d34.7394919!2m1!1e3&fid=7
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: meekGee on 10/17/2013 08:00 pm
The pad itself is such a trivial piece of infrastructure (in comparison with launch pads) - why not place it in any convenient location west of the coastal road?   So it's not in anyone's way, and the trip back home is quick, and causes less disruptions.

As long as it's by the water, the divert maneuver can be made sideways, so no other facilities are at risk.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Helodriver on 10/17/2013 08:19 pm
I'm not sure ULA would appreciate the landing site being so close to SLC-6, nor its crucial part access road for the Delta IV deliveries.

This abandoned pad at the end of Spur Rd seems like a much better option. Very close to the ocean, and not so close to other active pads:
https://www.google.com/maps/preview#!data=!1m4!1m3!1d2917!2d-120.6191027!3d34.7394919!2m1!1e3&fid=7


That pad, a former Atlas ICBM silo, is Site 576E, and is still the launch pad for Orbital's Taurus rocket. The pad is also closer to SLC-2W a Delta II pad that will be active until 2017, than the Tow Road site on South Base is to SLC-6.

Being further uprange, it would require more propellant to boost the cores back to there. If they turn out do be interested in landing on North Base property, I'd expect the airfield would be their choice. Ample room, already built, near zero traffic.

A dedicated hew build pad somewhere closer to SLC-4 is more likely. The Tow Road site near the Boathouse (red roofed structure to the east) has a pad built that would need upgrading, a less onerous task than new greenfield construction considering the environmental impact process the base complies with on the coast.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lars_J on 10/17/2013 08:54 pm
Ok, since virtually all SpaceX launches from VAFB would be heading south, that makes a lot of sense. Thanks, Helodriver!
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: meekGee on 10/17/2013 09:10 pm

A dedicated hew build pad somewhere closer to SLC-4 is more likely. The Tow Road site near the Boathouse (red roofed structure to the east) has a pad built that would need upgrading, a less onerous task than new greenfield construction considering the environmental impact process the base complies with on the coast.

ahh...  I always forget about that.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: llanitedave on 10/18/2013 01:15 am

OK, I understand that Google and other maps often mislabel roads, so no reason for me to disagree here.  And I did see the Amtrak station, but I didn't see anything resembling a gate or guard station near that intersection, nor did there seem to be one on the south side of coast road.


Go to street view and you will see that road is blocked off south of the station.

Ah, thanks.  I should have thought of that.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: ChefPat on 10/18/2013 01:22 pm
An informed rumor at Vandenberg is pointing to this spot.

http://goo.gl/maps/U83SE (http://goo.gl/maps/U83SE)

Originally built as a parking and turning pad for trailers bearing barge delivered Space Shuttle External Fuel tanks. The concrete is in need of resurfacing currently, but it would allow returns from the south over the ocean without overflight of other critical facilities and it affords good ground handling access.

The runway, mentioned above, at this time has very little use and ample space. Scheduling conflicts could be easily managed. Inbound trajectories would involve more overflight of other infrastructure.
Can you show SLC 4E in relation to this site on the map?
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: corrodedNut on 10/18/2013 01:54 pm
An informed rumor at Vandenberg is pointing to this spot.

http://goo.gl/maps/U83SE (http://goo.gl/maps/U83SE)

Originally built as a parking and turning pad for trailers bearing barge delivered Space Shuttle External Fuel tanks. The concrete is in need of resurfacing currently, but it would allow returns from the south over the ocean without overflight of other critical facilities and it affords good ground handling access.

The runway, mentioned above, at this time has very little use and ample space. Scheduling conflicts could be easily managed. Inbound trajectories would involve more overflight of other infrastructure.
Can you show SLC 4E in relation to this site on the map?

Here:
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lobo on 10/19/2013 04:49 am
An informed rumor at Vandenberg is pointing to this spot.

http://goo.gl/maps/U83SE (http://goo.gl/maps/U83SE)

Originally built as a parking and turning pad for trailers bearing barge delivered Space Shuttle External Fuel tanks. The concrete is in need of resurfacing currently, but it would allow returns from the south over the ocean without overflight of other critical facilities and it affords good ground handling access.

The runway, mentioned above, at this time has very little use and ample space. Scheduling conflicts could be easily managed. Inbound trajectories would involve more overflight of other infrastructure.
Can you show SLC 4E in relation to this site on the map?

Here:

Would there be any problem of trucking the returned F9 cores along the road that goes through SLC-6?  Can ULA restrict access on that road?  Or would they if they could?  Or is it the AFB that makes those decisions?
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: ChefPat on 10/19/2013 04:50 am
An informed rumor at Vandenberg is pointing to this spot.

http://goo.gl/maps/U83SE (http://goo.gl/maps/U83SE)

Originally built as a parking and turning pad for trailers bearing barge delivered Space Shuttle External Fuel tanks. The concrete is in need of resurfacing currently, but it would allow returns from the south over the ocean without overflight of other critical facilities and it affords good ground handling access.

The runway, mentioned above, at this time has very little use and ample space. Scheduling conflicts could be easily managed. Inbound trajectories would involve more overflight of other infrastructure.
Can you show SLC 4E in relation to this site on the map?

Here:
Thanks
Looks like a great spot to me. Over a mile to SLC 8. Around 7.5 road miles back to SLC 4. Good hills to contain any blast from the surounding area.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Helodriver on 10/19/2013 05:29 am
ULA does not control the road and has no say on what is transported there. The road runs past SLC-6 but does not enter the pad boundary. Even if it did its all USAF property.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Helodriver on 10/20/2013 01:10 am
Images shot today of the notional landing pad site on South Vandenberg, shared with permission of the source.

While the site seems ideal from  azimuth, conflict, access and safety considerations, some things were noticeable.

1. The pad is asphalt, not concrete, re-pouring with concrete would be necessary. To land more than one stage at a time, the pad would need to be expanded.

2. The circular center of the pad is very close to level  but the "wings" that extend along parallel to the road slope with the road at about 2 or 3 degrees from west to east.  If the pad is expanded, some leveling and filling would need to be done.

3. There are new powerlines being run to this site and the Boathouse dock that ULA uses.

4. The 1936 coastguard Boathouse, a historic site, is some 1000 feet  east.

http://i1351.photobucket.com/albums/p783/spacecoaster1/DSC00044_zpsafa6199a.jpg
http://i1351.photobucket.com/albums/p783/spacecoaster1/DSC00045_zps82271789.jpg
http://i1351.photobucket.com/albums/p783/spacecoaster1/DSC00046_zps9f6db18b.jpg
http://i1351.photobucket.com/albums/p783/spacecoaster1/DSC00047_zps15aba1ea.jpg
http://i1351.photobucket.com/albums/p783/spacecoaster1/DSC00048_zpsfb593bbd.jpg
http://i1351.photobucket.com/albums/p783/spacecoaster1/DSC00049_zpsbca0141b.jpg
http://i1351.photobucket.com/albums/p783/spacecoaster1/DSC00051_zps75be3a8a.jpg
http://i1351.photobucket.com/albums/p783/spacecoaster1/DSC00053_zpsb82f3ad4.jpg

http://i1351.photobucket.com/albums/p783/spacecoaster1/DSC00056_zps54e0a350.jpg
http://i1351.photobucket.com/albums/p783/spacecoaster1/DSC00057_zps87012098.jpg

(ATTACH IMAGES! - Andy)
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: llanitedave on 10/20/2013 01:40 am
The site definitely needs some work, but I don't see anything particularly onerous, if SpaceX is willing to pay for it.  Still looks like an excellent candidate.  The dog will certainly have to be moved, at least during landings.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Jcc on 10/20/2013 01:35 pm
The site definitely needs some work, but I don't see anything particularly onerous, if SpaceX is willing to pay for it.  Still looks like an excellent candidate.  The dog will certainly have to be moved, at least during landings.

I don't think they will be able to land on asphalt, the exhaust heat will melt it, so they need to put in a reinforced concrete pad at least. Those buildings look awfully close, too. They should find a spot further away from buildings.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lobo on 10/21/2013 07:30 pm
The site definitely needs some work, but I don't see anything particularly onerous, if SpaceX is willing to pay for it.  Still looks like an excellent candidate.  The dog will certainly have to be moved, at least during landings.

I don't think they will be able to land on asphalt, the exhaust heat will melt it, so they need to put in a reinforced concrete pad at least. Those buildings look awfully close, too. They should find a spot further away from buildings.

If the asphalt will have to be tore out and replaced with concrete...why put it at that particular spot then?  Zoom out of that Google maps and look west on the Tow Road.  Looks like there's nothing there.  They could put the concrete pad in farther to the west to get it farther away from the boat house, and/or they could make a south spur road off the Tow Road, farther to the west, and put a big concrete pad in there?  There looks like a lot of open land there to the southwest as the Tow Road angles to the northest where it meets the Coast Road.  Take a short spur right out there, but not too close to the water to avoid any EPA hassles or whatever by being too close to the shore.  Looks like a lot of room there, and it looks like it would be a good 3/4 of a mile or so from the boathouse.  And still around 1.5 miles from SLC-6.  I'd think that's give it a pretty good buffer area around it from anything of concern.

If you have to make a new wide spot in the road anyway, why put it in the old wide spot in the road?  Put it farther to the west.

Other than that, geographically, it looks pretty appealing.  A full water approach on flyback approach from the South.  Remote, desolate (no forest to catch fire if a core craters into the ground in the wrong spot), convienient access to transport the cores back to SLC-4, no return overflight of any structures or infrastructure.

Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Joffan on 10/21/2013 07:41 pm

If you have to make a new wide spot in the road anyway, why put it in the old wide spot in the road?  Put it farther to the west.

Other than that, geographically, it looks pretty appealing.  A full water approach on flyback approach from the South.  Remote, desolate (no forest to catch fire if a core craters into the ground in the wrong spot), convienient access to transport the cores back to SLC-4, no return overflight of any structures or infrastructure.


... or a bit further south, at Point Conception, looks good too. Off the base - could be either good or bad.
https://maps.google.com/maps?ll=34.456571,-120.463672&z=15&t=h
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lar on 10/21/2013 07:44 pm
If the asphalt will have to be tore out and replaced with concrete...why put it at that particular spot then?

Because it's almost level already and it's not hard to tear up asphalt and regrade? Not sure how much of a factor that is really, that sort of work is relatively cheap I think, compared to pad work (flame trenches and plumbing runs and the like).. but that's a reason, however weak.

Not knocking your analysis of alternatives, though.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lobo on 10/21/2013 10:23 pm
If the asphalt will have to be tore out and replaced with concrete...why put it at that particular spot then?

Because it's almost level already and it's not hard to tear up asphalt and regrade? Not sure how much of a factor that is really, that sort of work is relatively cheap I think, compared to pad work (flame trenches and plumbing runs and the like).. but that's a reason, however weak.

Not knocking your analysis of alternatives, though.

No worries.  Just throwing it out there for discussion. 
I don't know the rules and regulations for plowing up new land on the based.  I wouldn't think it would be a problem unless maybe it was too close to the water.   Even then being a base could be except from some of the fecal-storm of environmental regulations they throw at shore line development.  But I don't know that.
But, if it were to be a ways back from the waterline.  Maybe half way between there and the Tow Road on a spur. 

Unless there's some onerous regulations that would inflate costs, I think the actual work would be pretty cheap.  Just some excavation as it appears to be a gentle hill slope.  So excavate that and level it, and then put a big flat concrete pad on it sufficient to hand 3 F9 cores coming in at the same time...worse case scenario.  On launch days, they can have a crane stationed at SLC-4 that would roll out there and then put them on trucks for transport back to the HIV.    They could have maybe some sort of booster recovery structure there to monitor them as they approached.  Not sure what they actually need there for all that.

Such a pad could probably be used pretty easily for Dragon recover too.

Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: rst on 10/21/2013 11:04 pm
Question for the crowd:  Coking with kerosene is often cited as a reason to switch to methane as a fuel.  But I'm not sure I've seen any numbers on it.  Is there any way to estimate how long you could run a Merlin 1D before the amount of accumulated gunk got to be a performance issue?
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Joel on 10/21/2013 11:23 pm
Question for the crowd:  Coking with kerosene is often cited as a reason to switch to methane as a fuel.  But I'm not sure I've seen any numbers on it.  Is there any way to estimate how long you could run a Merlin 1D before the amount of accumulated gunk got to be a performance issue?


Musk has explicitly said that coking is not the main reason for switching to methane.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: baldusi on 10/22/2013 06:43 pm
Question for the crowd:  Coking with kerosene is often cited as a reason to switch to methane as a fuel.  But I'm not sure I've seen any numbers on it.  Is there any way to estimate how long you could run a Merlin 1D before the amount of accumulated gunk got to be a performance issue?

Last year they got an H2 dewar from the Shuttle pad. Much was speculated about it. But I guess you could have great thermal management for LNG. The big question is if any local have seen an LNG truck around.
BTW, for the guy who asked about the CH4 (methane) advantages, the ones I remember are:
1) Cheapest and most ubiquitous fuel (and with LOX cheapest combination).
2) Better isp than RP-1/LOX (albeit at worse density).
3) Easy to handle and lots of COTS infrastructure (read as LNG).
4) Very little to no cocking (i.e. easy to reuse).
5) Easy to do fuel rich stage combustion. Given that all the metallurgy for Oxidizer Rich Stage Combustion resides with Russians and Aerojet/Rocketdyne, this is important for a company that has to design its first SC cycle. H2 is "easy" to run fuel rich, but it's very difficult to handle in general.
6) Space storable. With relatively "little" MLI, you can store CH4 and LOX indefinitely in space. RP-1 starts to separate its components eventually, and H2 will boil off. This is an important point if you expect to take your fuel and use it for landing and launching again from Mars. Ditto for a return stage for Trans Earth Injection.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: go4mars on 10/22/2013 10:45 pm
Question for the crowd:  Coking with kerosene is often cited as a reason to switch to methane as a fuel.  But I'm not sure I've seen any numbers on it.  Is there any way to estimate how long you could run a Merlin 1D before the amount of accumulated gunk got to be a performance issue?
If pure methane, forever.  If LNG, practically forever.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: RDMM2081 on 10/22/2013 10:55 pm
Question for the crowd:  Coking with kerosene is often cited as a reason to switch to methane as a fuel.  But I'm not sure I've seen any numbers on it.  Is there any way to estimate how long you could run a Merlin 1D before the amount of accumulated gunk got to be a performance issue?
If pure methane, forever.  If LNG, practically forever.

Do we know the estimated levels of coking when running the M1D on Kerolox?  I assume SpaceX has torn apart a couple from McGregor after putting a couple thousand seconds or so on them, but have they shared any of that information as it pertains to reusability/refurbishment of the engines and core stages?

(PS Please be gentle, first post)
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: QuantumG on 10/22/2013 10:58 pm
(PS Please be gentle, first post)

.. and a great one it was!

Welcome to the forum.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: go4mars on 10/23/2013 04:37 am
Do we know the estimated levels of coking when running the M1D on Kerolox?  I assume SpaceX has torn apart a couple from McGregor after putting a couple thousand seconds or so on them, but have they shared any of that information as it pertains to reusability/refurbishment of the engines and core stages?
IIRC, Shotwell said one of them did 20 full-length burns.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: MP99 on 10/23/2013 07:47 am
Unless there's some onerous regulations that would inflate costs, I think the actual work would be pretty cheap.  Just some excavation as it appears to be a gentle hill slope.  So excavate that and level it, and then put a big flat concrete pad on it sufficient to hand 3 F9 cores coming in at the same time...worse case scenario. 

Don't level it - just fit two short legs on the booster! :))

Cheers, Martin
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: baldusi on 10/23/2013 01:31 pm
Question for the crowd:  Coking with kerosene is often cited as a reason to switch to methane as a fuel.  But I'm not sure I've seen any numbers on it.  Is there any way to estimate how long you could run a Merlin 1D before the amount of accumulated gunk got to be a performance issue?
If pure methane, forever.  If LNG, practically forever.

Do we know the estimated levels of coking when running the M1D on Kerolox?  I assume SpaceX has torn apart a couple from McGregor after putting a couple thousand seconds or so on them, but have they shared any of that information as it pertains to reusability/refurbishment of the engines and core stages?

(PS Please be gentle, first post)
You could always disassemble, clean, inspect, reintegrate and re-certify. That's what happened with the Shuttle Main Engines and it cost almost as much as a new engine. In the end, the reduction in coking is about easy and cheap re-usability.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: edkyle99 on 10/23/2013 03:36 pm
Do we know the estimated levels of coking when running the M1D on Kerolox?  I assume SpaceX has torn apart a couple from McGregor after putting a couple thousand seconds or so on them, but have they shared any of that information as it pertains to reusability/refurbishment of the engines and core stages?
SpaceX must use some solvent to clean the engines after their test firings.  Past practice (Rocketdyne, etc.)  was to use large volumes of TCE to flush kerosene engines both before and after tests, but TCE is now listed as hazardous and is a big problem when it reaches groundwater.  Whatever SpaceX uses, they are responsible for ensuring that it does not escape their test site.

 - Ed Kyle
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lar on 10/23/2013 05:34 pm
Unless there's some onerous regulations that would inflate costs, I think the actual work would be pretty cheap.  Just some excavation as it appears to be a gentle hill slope.  So excavate that and level it, and then put a big flat concrete pad on it sufficient to hand 3 F9 cores coming in at the same time...worse case scenario. 

Don't level it - just fit two short legs on the booster! :))

Cheers, Martin

Ha Ha, that assumes they have the rotation problems sorted well enough to come down with the short legs facing the right way...

More seriously, when landing on a level but basically featureless pad, how much does the final orientation matter? The stage can't BE rotating at the time of landing, not appreciably, or there will be undue strain on the legs, but does it really matter which way it faces?

The device that has to mate with it to safe it, then transport it away presumably can approach from any side...   Well I can see an edge case where the stage landed quite a bit off center and rotated in a way that the device[1] can't mate with the stage without driving off the edge of the pad into presumably non optimal softer ground...

Long term they no doubt will want landings with the logo facing the tv camera optimally. :)

1 - called what, a transporter? not exactly an erector
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: AncientU on 10/23/2013 05:45 pm
How 'bout Retriever?
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: StephenB on 10/23/2013 05:49 pm
Maybe someone with an aerospace engineering background can respond. It seems to me that the shape of the legs when folded against the core was chosen quite specifically.

Care to speculate on how form is following function here? Will the notch direct airflow outwards from the core (at 90 degree increments), perhaps lending it stability?
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: FutureSpaceTourist on 10/23/2013 08:11 pm
Not sure where best to post this, but today's news (http://www.flightglobal.com/blogs/hyperbola/2013/10/reaction-engines-expands-sabre-engine-project-to-finance-full-engine/) about RE developing a SABRE engine includes Alan Bond's views on SpaceX's re usability plans:

Quote
Bond noted his admiration at the pace of their development and even of their ability to reach orbit under engine failure conditions.  “I’ve been very impressed by the excess thrust of SpaceX’s (Falcon 9) launch vehicle and their ability reach orbit with an engine out.” said Bond.  Bond however remained skeptical of their reusable arrangement using two reusable stages noting that the stage integration costs stemming from the quality and accuracy required may significantly increase overal operational costs.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Jcc on 10/24/2013 12:28 am
Maybe someone with an aerospace engineering background can respond. It seems to me that the shape of the legs when folded against the core was chosen quite specifically.

Care to speculate on how form is following function here? Will the notch direct airflow outwards from the core (at 90 degree increments), perhaps lending it stability?

The notch allows it to fit around a cylindrical core. I doubt they would need it to affect the aerodynamics going up, they probably are trying to minimize the aerodynamic effect when stowed. But also make it look good.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: meekGee on 10/24/2013 01:48 am
Not sure where best to post this, but today's news (http://www.flightglobal.com/blogs/hyperbola/2013/10/reaction-engines-expands-sabre-engine-project-to-finance-full-engine/) about RE developing a SABRE engine includes Alan Bond's views on SpaceX's re usability plans:

Quote
Bond noted his admiration at the pace of their development and even of their ability to reach orbit under engine failure conditions.  “I’ve been very impressed by the excess thrust of SpaceX’s (Falcon 9) launch vehicle and their ability reach orbit with an engine out.” said Bond.  Bond however remained skeptical of their reusable arrangement using two reusable stages noting that the stage integration costs stemming from the quality and accuracy required may significantly increase overal operational costs.

That's a very sensible statement.  However - I think stage integration can be simplified a lot once there's enough motivation for it.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: beancounter on 10/24/2013 05:00 am
Not sure where best to post this, but today's news (http://www.flightglobal.com/blogs/hyperbola/2013/10/reaction-engines-expands-sabre-engine-project-to-finance-full-engine/) about RE developing a SABRE engine includes Alan Bond's views on SpaceX's re usability plans:

Quote
Bond noted his admiration at the pace of their development and even of their ability to reach orbit under engine failure conditions.  “I’ve been very impressed by the excess thrust of SpaceX’s (Falcon 9) launch vehicle and their ability reach orbit with an engine out.” said Bond.  Bond however remained skeptical of their reusable arrangement using two reusable stages noting that the stage integration costs stemming from the quality and accuracy required may significantly increase overal operational costs.

That's a very sensible statement.  However - I think stage integration can be simplified a lot once there's enough motivation for it.

Wouldn't surprise me if SpaceX are aiming for 'plug and play' integration.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: ugordan on 10/24/2013 07:48 am
Anyone want to speculate on the location of the 1st stage camera?

Looks like you nailed it. And was it you or someone else who identified the bump to the right of the words "2nd stage" as an ACS thruster cluster?

Edit: here's the other photo, from corrodednut. Presumably this is the other side of the rocket showing the thruster cluster at 180 degrees opposite:

http://forum.nasaspaceflight.com/index.php?topic=32859.msg1103849#msg1103849

The image posted in this thread (http://forum.nasaspaceflight.com/index.php?topic=32783.msg1112017#msg1112017) confirms that is a thruster cluster.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lars_J on 10/24/2013 08:01 am
Anyone want to speculate on the location of the 1st stage camera?

Looks like you nailed it. And was it you or someone else who identified the bump to the right of the words "2nd stage" as an ACS thruster cluster?

Edit: here's the other photo, from corrodednut. Presumably this is the other side of the rocket showing the thruster cluster at 180 degrees opposite:

http://forum.nasaspaceflight.com/index.php?topic=32859.msg1103849#msg1103849

The image posted in this thread (http://forum.nasaspaceflight.com/index.php?topic=32783.msg1112017#msg1112017) confirms that is a thruster cluster.

Good find! But what are the two visible metal boxes attached to the outside of the interstate? I don't recall seeing similar on the last vehicle.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: ugordan on 10/24/2013 08:07 am
But what are the two visible metal boxes attached to the outside of the interstate?

Temporary covers for antennas?
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: TrevorMonty on 10/24/2013 09:23 am
In regards to recovering of F9R stages, I think it may depend on mission. 13mt to LEO may be a one way trip, while  eg<10mt first stage is recoverable and eg <6mt 2nd stage is recoverable.This may explain  $70-125m price range for the F9H I've seen some where. $125m for 53mt as it is one way trip for everything. $70m for eg 30mt as two boosters are recoverable.  I've made up these figures so please don't quote them.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Nomadd on 10/24/2013 11:26 am
In regards to recovering of F9R stages, I think it may depend on mission. 13mt to LEO may be a one way trip, while  eg<10mt first stage is recoverable and eg <6mt 2nd stage is recoverable.This may explain  $70-125m price range for the F9H I've seen some where. $125m for 53mt as it is one way trip for everything. $70m for eg 30mt as two boosters are recoverable.  I've made up these figures so please don't quote them.
You have to figure engine out numbers too. Absolute maximum payloads would lose that capability.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: StephenB on 10/24/2013 06:41 pm
Maybe someone with an aerospace engineering background can respond. It seems to me that the shape of the legs when folded against the core was chosen quite specifically.

Care to speculate on how form is following function here? Will the notch direct airflow outwards from the core (at 90 degree increments), perhaps lending it stability?

The notch allows it to fit around a cylindrical core. I doubt they would need it to affect the aerodynamics going up, they probably are trying to minimize the aerodynamic effect when stowed. But also make it look good.

I was thinking about the aerodynamic effect of the undeployed legs on the stage going down. My assumption is that the legs are only deployed near the final burn.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Kabloona on 10/24/2013 07:27 pm
Maybe someone with an aerospace engineering background can respond. It seems to me that the shape of the legs when folded against the core was chosen quite specifically.

Care to speculate on how form is following function here? Will the notch direct airflow outwards from the core (at 90 degree increments), perhaps lending it stability?

The notch allows it to fit around a cylindrical core. I doubt they would need it to affect the aerodynamics going up, they probably are trying to minimize the aerodynamic effect when stowed. But also make it look good.

I was thinking about the aerodynamic effect of the undeployed legs on the stage going down. My assumption is that the legs are only deployed near the final burn.

Stability on the way down with legs stowed depends primarily on the axial distance between the center of pressure and the center of gravity. As long as the CP is far enough forward of the CG, the stage should stay upright on the way down, without tumbling, and the farther apart those two points are, the more stable it will be. The addition of the legs will move the CG slightly aft, but not much since they're far outweighed by engines and structure. While stowed may not affect CP much at all since their profile area will be small compared to the profile of the entire stage.

The other important aero effect on the way down is asymmetric roll torque, as demonstrated in the previous flight. It's conceivable that in certain attitudes the stowed legs might generate some roll torque, but presumbly SpaceX has done the analysis either to convince themselves that won't happen.

The stowed legs will add some drag on the way down, but otherwise probably won't have much aero effect until deployed. That's when they become much more significant, aerodynamically speaking, and likely shift the CP significantly aft, but hopefully not enough to cause the stage to tumble.

Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: aero on 10/24/2013 07:35 pm
A question. The fuel in S1 Cassiope centrifuged, and we assume it was due to aerodynamic roll imposed on S1 during high speed descent. I wonder if S1 shaking could have contributed to the fuel reaction?

I mean shaking something like what happens to the water in a 2 liter soft drink bottle when you put a cup (250 ml) of water in it and shake it around.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Joffan on 10/24/2013 09:06 pm
Maybe someone with an aerospace engineering background can respond. It seems to me that the shape of the legs when folded against the core was chosen quite specifically.

Care to speculate on how form is following function here? Will the notch direct airflow outwards from the core (at 90 degree increments), perhaps lending it stability?

The notch allows it to fit around a cylindrical core. I doubt they would need it to affect the aerodynamics going up, they probably are trying to minimize the aerodynamic effect when stowed. But also make it look good.

I was thinking about the aerodynamic effect of the undeployed legs on the stage going down. My assumption is that the legs are only deployed near the final burn.

The intention as I have understood the various remarks from SpaceX is that the legs will be deployed either immediately before or immediately after the reentry slowdown burn. They will be in fully-deployed position on the main atmospheric traverse ("fall").
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Jcc on 10/25/2013 01:26 am
The question of when the legs get deployed was discussed a few months ago, before we knew what they look like. I still think the stage will be allowed to follow a ballistic trajectory for the first part of the descent with the legs stowed, because it will be supersonic and the drag with the legs stowed will still be enough to bring it subsonic. Then deploy the legs and bring it down to a lower terminal velocity. If they need the legs for stability, that may affect when they are deployed, but I doubt deploying them while supersonic will help with stability.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: AncientU on 10/25/2013 01:44 am
Before they hit top of atmosphere, there will be no control issue if the legs deploy at different rates.  Seems that having them deployed during reentry burn would subject them to direct radiative heating.  So best to deploy them between burn and top of atmosphere IMO.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: aero on 10/25/2013 04:12 pm
If the legs are deployed prior to hitting the atmosphere then isn't there a risk of them being "aerodynamically removed?"
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Joffan on 10/25/2013 05:33 pm
If the legs are deployed prior to hitting the atmosphere then isn't there a risk of them being "aerodynamically removed?"

Sure there's a risk. They will have been designed to take the loads expected, but nothing beats actual testing. Whenever they are deployed, they will be subject to significant stresses.

If you're frightened of risks, don't bother with spaceflight. If you're aware of multiple risks and seeking to engineer the best overall trade-off between them - welcome.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Elmar Moelzer on 10/25/2013 06:00 pm
Judging from the RLV video that SpaceX released a while ago, which may or may not be accurate in this regard, the legs seem to be deployed pretty late. The LV seems to be much within the atmosphere at that point.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Joffan on 10/25/2013 07:07 pm
Yeah, this video (http://www.youtube.com/watch?v=kJrFwxE3lzI) - notice the first stage is already in its final burn, which is infeasibly late for leg deployment. Don't take that too seriously.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: cambrianera on 10/25/2013 07:10 pm
Pro/con of deployment of the legs in various phases:
1) brake/boostback burn
pro -big deceleration, opening of legs facilitated
con -legs must stand supersonic reentry speed (overengineered for landing)
      -legs works as air brakes also during the return to lauch site, requiring longer boostback firing

2) immediately after brake/boostback burn
pro -?
con -legs must stand supersonic reentry speed (overengineered for landing)
      -legs works as air brakes also during the return to lauch site, requiring longer boostback firing

3) in atmosphere, (about 10 km)
pro -ligther legs, engineered only for landing
con -opening of legs must overcome airflow

4) on final burn
pro -big deceleration, opening of legs facilitated
      -ligther legs, engineered only for landing
con -legs not really working as air brakes  (higher terminal velocity, more propellant for final burn)



Any comment?
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Joffan on 10/25/2013 07:21 pm
I think there are three burns, cambrianera:
1) boostback - above atmosphere, setting trajectory for near landing pad
2) braking - at atmosphere reentry, tweaking trajectory, slowing for safe re-entry
3) landing - retargetting to pad, stopping at ground.

I like leg deployment immediately after burn 2). This gives atmospheric braking and (with suitable aero profile) some resistance to roll. There's no implication for the boostback burn on this scenario, and it reduces the landing burn because of the lower terminal velocity.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: cambrianera on 10/25/2013 07:33 pm
I think there are three burns, cambrianera:
1) boostback - above atmosphere, setting trajectory for near landing pad
2) braking - at atmosphere reentry, tweaking trajectory, slowing for safe re-entry
3) landing - retargetting to pad, stopping at ground.

I like leg deployment immediately after burn 2). This gives atmospheric braking and (with suitable aero profile) some resistance to roll. There's no implication for the boostback burn on this scenario, and it reduces the landing burn because of the lower terminal velocity.

Three burns requires more propellant, you slow down a velocity earned with the boostback burn.
Anyway that's a possibility, easing the deployment of legs.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Joffan on 10/25/2013 07:40 pm
I don't really see how to avoid three burns. You have to kill the downrange velocity and start going uprange, and you aren't going to be able to get your uprange displacement inside the atmosphere.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Elmar Moelzer on 10/25/2013 07:42 pm
I don't really see how to avoid three burns. You have to kill the downrange velocity and start going uprange, and you aren't going to be able to get your uprange displacement inside the atmosphere.
They had only two on the last mission. That one did not return to the pad, but I do not quite see the difference there.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: meekGee on 10/25/2013 07:46 pm
I don't know for sure, but I think they only executed burns #2 and #3.

Burn #1 is just a trajectory change, there are no aerodynamic unknowns about it.

I think there's a theoretical possibility of eliminating burn #2 - you can achieve most of its objectives with a proper #1 burn - but at least from the comments on this board, I don't think that's the plan.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: cambrianera on 10/25/2013 07:51 pm
I don't really see how to avoid three burns. You have to kill the downrange velocity and start going uprange, and you aren't going to be able to get your uprange displacement inside the atmosphere.

Then? Something like 500 m/s (horizontal) could be enough to return to the launch site and also a survivable reentry speed.
Not a showstopper (at least for F9 first stage and FH boosters).
This doesn't mean SpaceX is going with two burns, only that two could be feasible and uses less propellant (that means more payload)
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: meekGee on 10/25/2013 08:02 pm
It's a bit counterintuitive, but you can kill the vertical speed already at burn $#1.

In vacuum, vertically, the speed you're going up is also the speed you're going to be coming down (through the same altitude).

So if in addition to the horizontal course reversal, you burn to reduce you upwards velocity, this will also reduce your downward velocity at the reentry interface as it occurs a few minutes later, pretty much 1:1 (assuming deep suborbital velocities here).

You "lose" any velocity reduction that was a result of drag in the intervening time period.  You also don't have engine control during the entry interface, which I think might be important.   I don't know for sure, but I think SpaceX might be executing burn #2 not before the entry interface, but actually during it, as a means of both slowing down and of controlling the stage against tumbling.  It depends on how long such a control burn has to be.   If that's their secret ingredient, then definitely you need 3 burns, since you don't want to "waste" that delta-v before you enter that controlled phase.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Joffan on 10/25/2013 08:06 pm
I don't really see how to avoid three burns. You have to kill the downrange velocity and start going uprange, and you aren't going to be able to get your uprange displacement inside the atmosphere.

Then? Something like 500 m/s (horizontal) could be enough to return to the launch site and also a survivable reentry speed.
Not a showstopper (at least for F9 first stage and FH boosters).
This doesn't mean SpaceX is going with two burns, only that two could be feasible and uses less propellant (that means more payload)

Getting adequate velocity for an in-atmosphere uprange traverse might actually need more propellant than the 3-burn solution, as well as risking higher atmospheric velocities. But if SpaceX take this option - if it is feasible, which I am not convinced of - then you are right that early leg deployment would need a bigger braking/boostback burn.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: cambrianera on 10/25/2013 08:14 pm
Getting adequate velocity for an in-atmosphere uprange traverse might actually need more propellant than the 3-burn solution, as well as risking higher atmospheric velocities. But if SpaceX take this option - if it is feasible, which I am not convinced of - then you are right that early leg deployment would need a bigger braking/boostback burn.
Why in-atmosphere uprange traverse? Biggest part of RTLS travel could be outside the atmosphere during a ballistic boostback.
That's why killing your upward velocity in burn #1 is a nonsense (@meekGee).
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Elmar Moelzer on 10/25/2013 08:24 pm
I am also confused by the idea of killing the upwards velocity. I thought you want to keep coasting up as long as possible, so you have more time to slow down horizontally and then fly back to the landing site.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Joffan on 10/25/2013 08:34 pm
Getting adequate velocity for an in-atmosphere uprange traverse might actually need more propellant than the 3-burn solution, as well as risking higher atmospheric velocities. But if SpaceX take this option - if it is feasible, which I am not convinced of - then you are right that early leg deployment would need a bigger braking/boostback burn.
Why in-atmosphere uprange traverse? Biggest part of RTLS travel could be outside the atmosphere during a ballistic boostback.

Well, that's the 3-burn solution that I've been talking about. It's the two-burn solution that needs in-atmosphere traverse.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: cambrianera on 10/25/2013 08:35 pm
I am also confused by the idea of killing the upwards velocity. I thought you want to keep coasting up as long as possible, so you have more time to slow down horizontally and then fly back to the landing site.

You want to keep coasting up because this gains you more time to return to launch site; more time, less boostback speed needed.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: cambrianera on 10/25/2013 08:40 pm
Getting adequate velocity for an in-atmosphere uprange traverse might actually need more propellant than the 3-burn solution, as well as risking higher atmospheric velocities. But if SpaceX take this option - if it is feasible, which I am not convinced of - then you are right that early leg deployment would need a bigger braking/boostback burn.
Why in-atmosphere uprange traverse? Biggest part of RTLS travel could be outside the atmosphere during a ballistic boostback.

Well, that's the 3-burn solution that I've been talking about. It's the two-burn solution that needs in-atmosphere traverse.
What's that?
First burn is outside the atmosphere, killing horizontal speed and gaining boostback horizontal speed (1500 to -500 m/s), second and final burn is for landing.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: meekGee on 10/25/2013 08:49 pm
Getting adequate velocity for an in-atmosphere uprange traverse might actually need more propellant than the 3-burn solution, as well as risking higher atmospheric velocities. But if SpaceX take this option - if it is feasible, which I am not convinced of - then you are right that early leg deployment would need a bigger braking/boostback burn.
Why in-atmosphere uprange traverse? Biggest part of RTLS travel could be outside the atmosphere during a ballistic boostback.
That's why killing your upward velocity in burn #1 is a nonsense (@meekGee).

Clearly you don't kill all of it - you keep enough to get back, but nobody said you had to eliminate it in order to re-enter successfully.

If you have a certain amount of upwards velocity, then it gives you a certain amount of "dwell time".  During this time, you need to get back, so this dictates your horizontal velocity going back.  The more dwell time you have, the slower you need to go.  However, since you also have to zero out your forward velocity, it's a case of diminishing returns. 

However, as I said, I think they will work with 3 burns since a) it's more efficient, b) they WANT to do burn #2 for purposes of control, and because of that, they'd rather kill as much velocity as LATE as possible.  c) in that case, they might get some velocity reduction via drag, and that's obviously free dV.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: meekGee on 10/25/2013 08:50 pm
Getting adequate velocity for an in-atmosphere uprange traverse might actually need more propellant than the 3-burn solution, as well as risking higher atmospheric velocities. But if SpaceX take this option - if it is feasible, which I am not convinced of - then you are right that early leg deployment would need a bigger braking/boostback burn.
Why in-atmosphere uprange traverse? Biggest part of RTLS travel could be outside the atmosphere during a ballistic boostback.
That's why killing your upward velocity in burn #1 is a nonsense (@meekGee).

Clearly you don't kill all of it - you keep enough to get back, but nobody said you had to eliminate it in order to re-enter successfully.

If you have a certain amount of upwards velocity, then it gives you a certain amount of "dwell time".  During this time, you need to get back, so this dictates your horizontal velocity going back.  The more dwell time you have, the slower you need to go.  However, since you also have to zero out your forward velocity, it's a case of diminishing returns. 

However, as I said, I think they will work with 3 burns since a) it's more efficient, b) they WANT to do burn #2 for purposes of control, and because of that, they'd rather kill as much velocity as LATE as possible.  c) in that case, they might get some velocity reduction via drag, and that's obviously free dV.

So to clarify - someone asked why 3 burns, and I said "theoretically, you can do it with 2, but here are the reasons why 3 is preferable"
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: cambrianera on 10/25/2013 08:53 pm
So to clarify - someone asked why 3 burns, and I said "theoretically, you can do it with 2, but here are the reasons why 3 is preferable"
That's ok, and some good reasons also.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lars_J on 10/25/2013 09:01 pm
Getting adequate velocity for an in-atmosphere uprange traverse might actually need more propellant than the 3-burn solution, as well as risking higher atmospheric velocities. But if SpaceX take this option - if it is feasible, which I am not convinced of - then you are right that early leg deployment would need a bigger braking/boostback burn.
Why in-atmosphere uprange traverse? Biggest part of RTLS travel could be outside the atmosphere during a ballistic boostback.
That's why killing your upward velocity in burn #1 is a nonsense (@meekGee).

Clearly you don't kill all of it - you keep enough to get back, but nobody said you had to eliminate it in order to re-enter successfully.

If you have a certain amount of upwards velocity, then it gives you a certain amount of "dwell time".  During this time, you need to get back, so this dictates your horizontal velocity going back.  The more dwell time you have, the slower you need to go.  However, since you also have to zero out your forward velocity, it's a case of diminishing returns. 

However, as I said, I think they will work with 3 burns since a) it's more efficient, b) they WANT to do burn #2 for purposes of control, and because of that, they'd rather kill as much velocity as LATE as possible.  c) in that case, they might get some velocity reduction via drag, and that's obviously free dV.

Yep, I think you are right. I'll attach this oldie but goodie example of boost-back profile. Note that at stage separation, the stage is still on an upward trajectory, and the purpose of that first burn is simply to reverse the horizontal component.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: meekGee on 10/25/2013 09:29 pm
That's the picture I had in mind.

Does anyone know if burn #2 is a single or a triple engine burn?  In the last flight, the combined #1-2 burn seems to have been a 3-engine burn.  The animated video IIRC, only showed two burns (#1 and #3)

Burn #2 is the secret ingredient of course.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: douglas100 on 10/25/2013 10:47 pm

...Burn #2 is the secret ingredient of course.

Yep, that's what allows the stage to survive entry (won't guess how many engines are used.) The other unknown was the aerodynamics of flight after entry. I imagine they got useful data from the last flight, but obviously they still have stuff to learn. It will be interesting to see how quickly they can master atmospheric flight and landing accuracy. Deploying the legs would seem to be the next step.

EDIT: and my guess re the previous discussion about time of leg deployment is, after entry when the stage is subsonic, but early enough to help with braking and stability.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Jcc on 10/25/2013 11:53 pm
I think burn #2 is 3 engines, also. They want to kill velocity pretty quickly, because it will be executed during initial reentry where there is some atmosphere already. Two reasons why I say that, first, because if they are already experience some drag, it helps reduce the fuel requirement. Second, because that is what they just did on the first reentry attempt: supersonic retro propulsion, the video shows the exhaust being blasted back by the atmosphere.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: meekGee on 10/26/2013 01:24 am
I think burn #2 is 3 engines, also. They want to kill velocity pretty quickly, because it will be executed during initial reentry where there is some atmosphere already. Two reasons why I say that, first, because if they are already experience some drag, it helps reduce the fuel requirement. Second, because that is what they just did on the first reentry attempt: supersonic retro propulsion, the video shows the exhaust being blasted back by the atmosphere.

Counterpoint:

If they burn with one engine, I think they have enough control to keep the stage from tumbling (much more than the RCS gives them).   If they do, then the longer the burn, the more aerobraking they get.  Is it significant?  That depends on when (how high) the burn occurs, and that's a secret no doubt.

Why did they use three engines?  Because they had a lot of propellant, and the idea is to first succeed, and then creep the parameters towards failure, rather than the other way around.

Just a guess though.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Jcc on 10/26/2013 02:10 am
I think burn #2 is 3 engines, also. They want to kill velocity pretty quickly, because it will be executed during initial reentry where there is some atmosphere already. Two reasons why I say that, first, because if they are already experience some drag, it helps reduce the fuel requirement. Second, because that is what they just did on the first reentry attempt: supersonic retro propulsion, the video shows the exhaust being blasted back by the atmosphere.

Counterpoint:

If they burn with one engine, I think they have enough control to keep the stage from tumbling (much more than the RCS gives them).   If they do, then the longer the burn, the more aerobraking they get.  Is it significant?  That depends on when (how high) the burn occurs, and that's a secret no doubt.

Why did they use three engines?  Because they had a lot of propellant, and the idea is to first succeed, and then creep the parameters towards failure, rather than the other way around.

Just a guess though.

You have a point there too. They had to do a 3 engine burn because they were killing Mach 6 velocity, that won't be the case after boost back.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Elmar Moelzer on 10/27/2013 03:50 pm
I am also confused by the idea of killing the upwards velocity. I thought you want to keep coasting up as long as possible, so you have more time to slow down horizontally and then fly back to the landing site.

You want to keep coasting up because this gains you more time to return to launch site; more time, less boostback speed needed.
Which is what I said. So why did someone suggest that they would want to kill the upwards velocity?
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: PreferToLurk on 10/27/2013 05:38 pm
I am also confused by the idea of killing the upwards velocity. I thought you want to keep coasting up as long as possible, so you have more time to slow down horizontally and then fly back to the landing site.

You want to keep coasting up because this gains you more time to return to launch site; more time, less boostback speed needed.
Which is what I said. So why did someone suggest that they would want to kill the upwards velocity?
It wasn't me, but just to play devils advocate for a bit:  There will be somewhat of a tradeoff. you dont necessarily want the absolute maximum amount of coast time. the longer you coast, the higher you go, the higher you go, the more breaking burn you will need.

Given that, I think the OP was merely inquiring about the parameters of that trade. -- Is it possible that the boostback burn attempts to kill any vertical velocity?  If the trade is going the other way, will the boost back actively try to loft the stage even higher? 

These are all questions that we will probably never have good answers for -- likely part of SpaceX's secret sauce.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: aero on 10/27/2013 05:54 pm
Re. killing the upward component of velocity with boost back. I don't think so. The upward velocity is not that great compared to the horizontal velocity at staging. For Cassiopi I calculated roughly 1.4 km/s vertical and about 2.4 km/s horizontal. This results from the gravity turn being done long before staging and the high acceleration resulting from fuel burn off comes after the gravity turn.

It seems to me that the most fuel efficient boost back would be a ballistic trajectory targeted at the landing pad, (with aero drag considered) and making use of the existing vertical velocity component. This trajectory will be a little more flat than most of the drawings I've seen. JMO
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: MP99 on 10/27/2013 06:19 pm
Anyone care to speculate whether the reentry burn provides any heat shielding for the stage, IE diverting the incoming airflow from impinging on the engines and tank walls?

Cheers, Martin
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Jcc on 10/27/2013 07:23 pm
Anyone care to speculate whether the reentry burn provides any heat shielding for the stage, IE diverting the incoming airflow from impinging on the engines and tank walls?

Cheers, Martin

Good question. It also provides some heat, which apparently gets blown back to and around the stage, so it could be an even trade.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: meekGee on 10/27/2013 08:07 pm
I am also confused by the idea of killing the upwards velocity. I thought you want to keep coasting up as long as possible, so you have more time to slow down horizontally and then fly back to the landing site.

You want to keep coasting up because this gains you more time to return to launch site; more time, less boostback speed needed.
Which is what I said. So why did someone suggest that they would want to kill the upwards velocity?

Elmar - it was me, and I was responding to this question from you:

I don't really see how to avoid three burns. You have to kill the downrange velocity and start going uprange, and you aren't going to be able to get your uprange displacement inside the atmosphere.
They had only two on the last mission. That one did not return to the pad, but I do not quite see the difference there.

I said that while it is possible to do only two burns (and showed how) it is not optimal, and three is preferred - and gave 3-4 reasons why.

We then agreed that burn #2 is the magic burn, I was arguing that perhaps it's best done with a single engine, and we discussed why in the last flight they used 3 for the combined 1-2 burn.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Avron on 10/27/2013 08:14 pm
Anyone care to speculate whether the reentry burn provides any heat shielding for the stage, IE diverting the incoming airflow from impinging on the engines and tank walls?

Cheers, Martin

Good question. It also provides some heat, which apparently gets blown back to and around the stage, so it could be an even trade.

I was wondering the same, however, I think the burn is more about reducing velocity at interface to the thicker atmosphere, with two aims, one to ensure the stage (vehicle) is orientated correctly  and the aero-forces don't rip the stage apart.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: smoliarm on 10/28/2013 08:31 am
Anyone care to speculate whether the reentry burn provides any heat shielding for the stage, IE diverting the incoming airflow from impinging on the engines and tank walls?

Cheers, Martin

Good question. It also provides some heat, which apparently gets blown back to and around the stage, so it could be an even trade.

I was wondering the same, however, I think the burn is more about reducing velocity at interface to the thicker atmosphere, with two aims, one to ensure the stage (vehicle) is orientated correctly  and the aero-forces don't rip the stage apart.

>>Anyone care to speculate whether the reentry burn provides any heat shielding for the stage
Yes. It reduces the heating at reentry, which is quantitatively:
*** Amount of heat is approximately proportional to reentry speed squared ***
So, it the reentry burn reduces V to zero, there will be almost no heating during reentry, and one can say it acts as a heat shield, but it's just a figure of speech.

>>It also provides some heat, which apparently gets blown back to and around the stage...
Not really, the reentry burn happens actually in space vacuum, there is no gas pressure for "blow back".
By the same reason it does not divert "the incoming airflow", at 100 km altitude there is no air to flow ;)
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lars_J on 10/28/2013 03:35 pm
>>It also provides some heat, which apparently gets blown back to and around the stage...
Not really, the reentry burn happens actually in space vacuum, there is no gas pressure for "blow back".
By the same reason it does not divert "the incoming airflow", at 100 km altitude there is no air to flow ;)

Not correct... at least for the last mission. If you look at the video (at 2:40), the 3 engine restart appears to be happening as the stage has encountered the top of the atmosphere. (it looks turbulent and not at all like a vacuum restart, also the video states that it occurred at 63km altitude)

https://www.youtube.com/watch?v=RtDbDMRG3q8
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: cambrianera on 10/28/2013 04:22 pm
Density of atmosphere at 40 km is 3,6 x 10-3 (0,0036) that of sea level.
At 60 km is 2,4 x 10-4 (0,00024).

Graph from wikipedia.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: meekGee on 10/28/2013 04:23 pm
Density of atmosphere at 40 km is 3,6 x 10-3 (0,0036) that of sea level.
At 60 km is 2,4 x 10-4 (0,00024).

Graph from wikipedia.

This is why they invented log scale...
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: smoliarm on 10/28/2013 05:03 pm
>>It also provides some heat, which apparently gets blown back to and around the stage...
Not really, the reentry burn happens actually in space vacuum, there is no gas pressure for "blow back".
By the same reason it does not divert "the incoming airflow", at 100 km altitude there is no air to flow ;)

Not correct... at least for the last mission. If you look at the video (at 2:40)...


Sorry, Lars, can't agree, even after looking at the video.
(Although, Californian sky is a miracle, for sure)

I do not know at which altitude the relight of the 1st stage took place (btw, does anybody has a reference ?), I assume it was at approx. 100 km (from some past mission profile, which I admit, may be not relevant to this flight).
But I do know that everything above 80 km in essentially a vacuum, from common laboratory viewpoint.

Do you remember that classic high school science demo with lead bullet and feather dropped side by side and falling - side by side - in a glass tube ? Typically, the vacuum in this demo is maintained with a simple rotary oil pump and the *vacuum* in the tube is only about 5*10-4 atm. You can check in wiki to which altitude it corresponds, I'm lazy, on the top of my head it's something like 40 to 60 km.

With respect to the video you referred - "it looks turbulent" - I'm sorry, I have no idea how laminar should look there :) I'm not a rocket scientist.
I just work with vacuum all my life and I know that at pressures of 10-4 atm one should use term "air flow" with caution. To feel this "flow" you need A LOT of speed.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lars_J on 10/28/2013 05:09 pm
>>It also provides some heat, which apparently gets blown back to and around the stage...
Not really, the reentry burn happens actually in space vacuum, there is no gas pressure for "blow back".
By the same reason it does not divert "the incoming airflow", at 100 km altitude there is no air to flow ;)

Not correct... at least for the last mission. If you look at the video (at 2:40)...


Sorry, Lars, can't agree, even after looking at the video.
(Although, Californian sky is a miracle, for sure)

I do not know at which altitude the relight of the 1st stage took place (btw, does anybody has a reference ?), I assume it was at approx. 100 km (from some past mission profile, which I admit, may be not relevant to this flight).
But I do know that everything above 80 km in essentially a vacuum, from common laboratory viewpoint.

If you read my entire post, you would see that according to the video, the burn started at 63 km.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: kch on 10/28/2013 05:20 pm
>>It also provides some heat, which apparently gets blown back to and around the stage...
Not really, the reentry burn happens actually in space vacuum, there is no gas pressure for "blow back".
By the same reason it does not divert "the incoming airflow", at 100 km altitude there is no air to flow ;)

Not correct... at least for the last mission. If you look at the video (at 2:40)...


Sorry, Lars, can't agree, even after looking at the video.
(Although, Californian sky is a miracle, for sure)

I do not know at which altitude the relight of the 1st stage took place (btw, does anybody has a reference ?), I assume it was at approx. 100 km (from some past mission profile, which I admit, may be not relevant to this flight).
But I do know that everything above 80 km in essentially a vacuum, from common laboratory viewpoint.

If you read my entire post, you would see that according to the video, the burn started at 63 km.

"What is this 'read' thing you speak of?"   ;)

(it *is* also in the video -- stage relight announced verbally & altitude shown at the left side of the screen)
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: MP99 on 10/28/2013 05:58 pm
I do not know at which altitude the relight of the 1st stage took place (btw, does anybody has a reference ?), I assume it was at approx. 100 km (from some past mission profile, which I admit, may be not relevant to this flight).
But I do know that everything above 80 km in essentially a vacuum, from common laboratory viewpoint.

Got down to 52 km while burn was progressing, according to this screenshot. (Edit: and was nearly 2km/s at the start of the burn at ~63km.)

Also, Shuttle (yes, travelling *much* faster!), hit entry interface around 120 km.

cheers, Martin

PS I presume there must be *some* effect from atmosphere above this (at F9's speeds), as PLF is retained until over 100 km altitude.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: smoliarm on 10/28/2013 06:03 pm
...
If you read my entire post, you would see that according to the video, the burn started at 63 km.

Sorry, my bad, did not notice the number.

OK, now we have everything to check my point quantitatively:
Altitude = 63.5 km;
Air density at 60 km is 2,4 x 10-4 that of sea level. (Thanks, cambrianera :) )
And velocity = 6814 km/hr

I would suggest you calculate dynamic pressure per sq.cm at these conditions and then -- calculate velocity which gives the same dynamic pressure at sea level.
I'm afraid it's going to be on the order of 1 km/hr -- not much of an airflow.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: deltaV on 10/28/2013 06:17 pm
6814 * sqrt[2.4*10^-4] = 106, which is the equivalent sea level airspeed in km/hr.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: AncientU on 10/28/2013 07:38 pm
6814 * sqrt[2.4*10^-4] = 106, which is the equivalent sea level airspeed in km/hr.
In other words, nearly hurricane force winds
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Joffan on 10/28/2013 08:22 pm
We need cameras just above the inactive engines for a clear view on the way down - avoid some/all of the soot blow-back from the retrofire.

Make it so, Elon!
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: cambrianera on 12/05/2013 10:51 am
Bumping this thread to discuss the reentry of first stage during SES-8 mission.

SpaceX did improvement on the reentry of v1.1 (versus v1.0) at least on two main issues:
- lower staging speed (6 vs 10 mach);
- stronger base (minimal lateral fairings, small and stiff base fairings).

On SES-8 they decided to avoid the braking burn (to get more performance from the first stage) but kept the orientation of the first stage to verify the reentry conditions (amazing video at http://forum.nasaspaceflight.com/index.php?topic=24469.msg1128767#msg1128767).

The results of this test could be an answer if three reentry burns are needed:
1) boostback - above atmosphere, setting trajectory for near landing pad;
2) braking - at atmosphere reentry, tweaking trajectory, slowing for safe re-entry;
3) landing - retargetting to pad, stopping at ground;
(thanks Joffan, copied from your post http://forum.nasaspaceflight.com/index.php?topic=32998.msg1112643#msg1112643)
or two are enough:
1) boostback - above atmosphere, starting ballistic return to landing pad;
2) landing - final correction to pad, stopping at ground;

I'm anxiously waiting to learn something more on this.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: MP99 on 12/05/2013 11:09 am
oooh - we seem to have a 0-index/1-index communication issue here  :)

I counted the burns excluding the initial launch.  So what I meant was:

Launch is burn 0.
Fly-back is burn 1.
Slow-down is burn 2. (magic sauce, unknown dV, hopefully minimal, so really only "keep straight")
Hover-slam is burn 3.

Are you a software guy, meekGee?
Only a software guy would start counting at zero, or discuss "index" on something as physical as burns. ;)

Other than that, we might be in violent agreement. :P

Launch is burn 1, I reckon.

But fly-back is restart 1.  :)

cheers, Martin
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: neoforce on 12/05/2013 01:17 pm
Bumping this thread to discuss the reentry of first stage during SES-8 mission.

SpaceX did improvement on the reentry of v1.1 (versus v1.0) at least on two main issues:
- lower staging speed (6 vs 10 mach);
- stronger base (minimal lateral fairings, small and stiff base fairings).

On SES-8 they decided to avoid the braking burn (to get more performance from the first stage) but kept the orientation of the first stage to verify the reentry conditions (amazing video at http://forum.nasaspaceflight.com/index.php?topic=24469.msg1128767#msg1128767).

The results of this test could be an answer if three reentry burns are needed:
1) boostback - above atmosphere, setting trajectory for near landing pad;
2) braking - at atmosphere reentry, tweaking trajectory, slowing for safe re-entry;
3) landing - retargetting to pad, stopping at ground;
(thanks Joffan, copied from your post http://forum.nasaspaceflight.com/index.php?topic=32998.msg1112643#msg1112643)
or two are enough:
1) boostback - above atmosphere, starting ballistic return to landing pad;
2) landing - final correction to pad, stopping at ground;

I'm anxiously waiting to learn something more on this.

I posted on the SES discussion thread and then saw you bumped this one.  Its relevant so I'll repost here.  My main question is are we seeing them just "keeping the orientation of the first stage"  or did we see a relight immediately after stage separation?

Here is what I posted on the other thread:

Clearly, even without recovery plans, SpaceX used the first stage on this flight to continue testing various elements of the recovery envelope.  We all hope SpaceX tells us officially what they tested with SES.  Until they do, it is all speculation. 

I'd like to add a thought I don't think I haven't seen on these boards yet.  Maybe I'm missing the obvious, but does everyone agree that we are seeing the first stage is lit?  The fact that we see the fairing is a reflection of a perfect angle of the sun.  But for the first stage, do we all think Merlin(s) are lit and its not just a reflection?  It looks that way to my untrained eye.

If so, the most recent video seems to show the relight of the first stage within about 10-15 seconds of Second Stage Start.  During Cassiope the only timestamp reference I found is from the web cast when at around 8:00 on the mission clock there is audio about first stage relight. 

So it seems to me that instead of using the SES flight to test just the re-entry part of the flight profile (like they did on Cassiope), might they have also been testing part of the boost back phase?  (Clearly in Cassiope they did not worry about boost back at all)  I doubt they tested full boost back, due to range security concerns, but maybe they did something like cancel forward velocity to zero to get another data point?

Again, all speculation at this point.  I hope we hear details from SpaceX.


===

An interesting aside.  There are three videos on youtube of Cassiope.  People who recorded the live webcast, SpaceX edited release of that webcast, then Spacex release of mission highlights. There are problems with all three.  The spaceX ones are edited, the live webcast had audio drop out every time the downlink was lost.  As for the relight information, here is what I found in those three videos:

- 8:00 mark on mission clock shown in webcast, a voice says "first stage is burning.. uh relighting at this time"
- 8:00 mark on mission clock shown in space X release of webcast has NO audio at all.
- Mission overview video has the voice saying "first stage is relighting at this time" but doesn't show a mission clock.

These differences are probably not sinister, its just editing and audio track anomalies.  But it shows that the information I found about when the relights were for Cassiope is really not complete.  So I really can't be sure when the first relight was during Cassiope.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: dcporter on 12/05/2013 01:57 pm
They're not heading back to the launchpad on CRS3, right? My understanding was that they'd be trying for a point farther south with no people nearby.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: cambrianera on 12/05/2013 02:05 pm
@neoforce,
I answered on SES-8 discussion thread but repeating here.
No relight of first stage engines happened.
What you see is first stage in full sunlight against a dimming evening sky; if you have still doubts, please review the video and consider you can't see merlins' first stage plumes, while thrusters' plumes are easily visible.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: meekGee on 12/05/2013 02:24 pm
They're not heading back to the launchpad on CRS3, right? My understanding was that they'd be trying for a point farther south with no people nearby.

Musk said they are trying to get approval to get back to shore, full landing.  He mentioned it only once.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: mlindner on 12/05/2013 02:24 pm
No relight of first stage engines happened.

I really suggest you take a look at L2.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: dcporter on 12/05/2013 02:28 pm
They're not heading back to the launchpad on CRS3, right? My understanding was that they'd be trying for a point farther south with no people nearby.

Musk said they are trying to get approval to get back to shore, full landing.  He mentioned it only once.

Yes, but back to shore at a point further south with no people. I don't recall where I read or heard it, but I believe the quote was directly from Musk after the CASSIOPE launch.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: meekGee on 12/05/2013 02:32 pm
They're not heading back to the launchpad on CRS3, right? My understanding was that they'd be trying for a point farther south with no people nearby.

Musk said they are trying to get approval to get back to shore, full landing.  He mentioned it only once.

Yes, but back to shore at a point further south with no people. I don't recall where I read or heard it, but I believe the quote was directly from Musk after the CASSIOPE launch.

Yes, definitely not to the pad.  If I were to go, I'd look for a vantage point to the landing, not the launch.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Elmar Moelzer on 12/05/2013 02:50 pm

Maybe that's why nobody can ever follow my driving directions...  (Take the zeroth driveway on your left) 

Otherwise, it's complicated.  (Studied EE, ended up doing some CE, mostly ME)  But I'm C Native, so zero's it.

ANYWAY.

The launch was not a "burn" in my mind.  It was, you know, THE LAUNCH.
I got you, but then I am a software guy too ;)
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Jim on 12/05/2013 03:03 pm

Yes, definitely not to the pad.  If I were to go, I'd look for a vantage point to the landing, not the launch.

There isn't any for either coast
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: cambrianera on 12/05/2013 03:04 pm
No relight of first stage engines happened.

I really suggest you take a look at L2.

Responding to neoforce's doubts, I was referring to the video: the light is not due to first stage engines relighting.
I don't know what happened later (not L2 member).

Anyway, I apologize if I wrote something to be seen as misleading.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Norm38 on 12/05/2013 04:04 pm
SpaceX hopes to launch another commercial satellite from the Cape before the year is out, for Thaicom.
Musk said SpaceX might try to recover that rocket's first stage from the ocean, depending in part on data collected during the SES-8 mission.
Link : http://www.usatoday.com/story/tech/2013/12/04/spacex-launch-successful/3866655/

What we were told prevented the soft landing of the Cassiope 1st stage was the stage spinning up, that exceeded RCS roll authority.  And the fix SpaceX mentioned was placing the landing legs, to provide extra drag for the roll.

To talk of recovering the Thaicom stage, doesn't that imply the roll issue has been fixed?  How?  There's been no talk of legs being on this flight, only on CRS-3.

Also, the "better than required" performance on SES-8 indicates that have extra margin. Maybe.
Would that extra margin be enough to put legs on the Thaicom flight?

I wonder if anything new was learned about the roll from the SES-8 stage re-entry?  Doubtful right?  Since without the braking burn it never followed the flight envelope to the point where roll developed.
Anyway, another interesting thing to keep track of.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: TrevorMonty on 12/05/2013 04:05 pm
If they are going land it at a remote location. It will need to have good road access so they can truck it out.
Spacex may need to demo a few successful landings before being allowed to land at pad.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Kabloona on 12/05/2013 04:21 pm


To talk of recovering the Thaicom stage, doesn't that imply the roll issue has been fixed?  How?  There's been no talk of legs being on this flight, only on CRS-3.



Since SpaceX apparently believes the roll was aero-induced, they may already have done some aerodynamic tweaks on the SES vehicle, or somehow added more control authority, to experiment with nulling that roll torque. One way to improve control authority would be to up the GN2 pressure, assuming the thrusters, tanks and plumbing weren't already operating at their limits, and maybe swap in higher-pressure components if necessary.

 And since we saw in video that S1 did its post-sep ACS thrusting, I'd be surprised if SpaceX didn't go ahead and actually attempt a relight with residuals.

If so, they may have been able to get enough data before stage breakup to verify a fix to the roll issue.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: kevin-rf on 12/05/2013 05:30 pm
If they are going land it at a remote location. It will need to have good road access so they can truck it out.
Spacex may need to demo a few successful landings before being allowed to land at pad.

One can assume it will not be landing to far inland, so all they need is a good hovercraft ;)
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: douglas100 on 12/05/2013 10:25 pm

Since SpaceX apparently believes the roll was aero-induced, they may already have done some aerodynamic tweaks on the SES vehicle, or somehow added more control authority, to experiment with nulling that roll torque. One way to improve control authority would be to up the GN2 pressure, assuming the thrusters, tanks and plumbing weren't already operating at their limits, and maybe swap in higher-pressure components if necessary.

 And since we saw in video that S1 did its post-sep ACS thrusting, I'd be surprised if SpaceX didn't go ahead and actually attempt a relight with residuals.

If so, they may have been able to get enough data before stage breakup to verify a fix to the roll issue.

Quite possibly. There was a comment about information on L2 about what was done post staging on this flight. (Don't have L2 myself.) But as Musk's remarks were reported, there was no mention of legs being fitted on the next flight. It's not clear that the legs are even ready. SpaceX might be waiting for F9R to fly to test them first.

I think they might want to repeat what they did on the CASSIOPE flight with the next launch and attempt to recover the stage from the sea. I also think that getting Thaicom 6 off before the end of the year is possible, but I think it's more likely it will slip to early January. But a slip of a week or two isn't a big deal: performing another successful flight is.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Antares on 12/06/2013 04:02 am
I'd think from the Cape Canaveral jetty to Complex 46 would be a pretty easy sightline.  Might not be able to see touchdown, but the stage would be visible above the treeline.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Jakusb on 12/06/2013 07:08 am

No relight of first stage engines happened.

I really suggest you take a look at L2.
Hi, I am a L2 member, but no clue to what you refer to. Can you please post a link?
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: cosmicvoid on 12/06/2013 07:15 am

No relight of first stage engines happened.

I really suggest you take a look at L2.
Hi, I am a L2 member, but no clue to what you refer to. Can you please post a link?
http://forum.nasaspaceflight.com/index.php?topic=33397.msg1128213#msg1128213
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: macpacheco on 12/09/2013 05:05 pm
Going one step at a time... I would rather have them do a water landing at least half a mile from shore, in the shallowest spot they can find (but far away from people and any wild life reserve). If it lands intact, easy peasy to recover, if something goes wrong and it breaks up, they can recover every single piece with divers (if its shallow enough, just a sea crane could get everything).

This way they can prove to NASA they have terminal control, that they're able land very precisely outside Grasshopper tests, and if it goes well, they could land in a somewhat remote area with just concrete on away from the active areas of the Cape (for the CRS launch).

Even with seawater, they could refurbish everything that got wet for a relative bargain and use it as GH2 !

I wouldn't believe NASA would like to see a crash inland (even a small risk), so I don't think this speculation of a surface landing for Thaicom-6 launch will pan out (even if legs are ready and Thaicom contract gives them enough fuel reserves for landing).

Finally Falcon 9 quoted performance for standard GTO launch is 4850Kg payload, a 30% hit leaves 3395Kg payload capability, very little margin over Thaicom-6 3300Kg (i've seen quotes for both 3,2 and 3,3 tons). If the launch is super sync GTO, then 15% hit for at sea recovery might be the only choice anyways. I know Elon said F9R performed better than expected, but we don't know how much better !
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: savuporo on 12/09/2013 06:43 pm
so I don't think this speculation of a surface landing for Thaicom-6 launch will pan out (even if legs are ready and Thaicom contract gives them enough fuel reserves for landing).

Finally Falcon 9 quoted performance for standard GTO launch is 4850Kg payload, a 30% hit leaves 3395Kg payload capability, very little margin over Thaicom-6 3300Kg (i've seen quotes for both 3,2 and 3,3 tons). If the launch is super sync GTO, then 15% hit for at sea recovery might be the only choice anyways. I know Elon said F9R performed better than expected, but we don't know how much better !
Thaicom 6 is exact same bus as SES-8 was and is quoted to be 125kg heavier.
http://www.orbital.com/NewsInfo/Publications/Thaicom6_Factsheet.pdf
http://www.orbital.com/newsinfo/publications/SES-8_Fact.pdf
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Wetmelon on 12/09/2013 07:12 pm
I know Elon said F9R performed better than expected, but we don't know how much better !

He quoted the engines running at about 85% capacity.  Not sure how exactly that translates to fuel efficiency though.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lourens on 12/09/2013 08:10 pm
If they are going land it at a remote location. It will need to have good road access so they can truck it out.
Spacex may need to demo a few successful landings before being allowed to land at pad.

One can assume it will not be landing to far inland, so all they need is a good hovercraft ;)
I've been thinking that a cargo airship (http://www.aerospace-technology.com/projects/cargolifter/) would be ideal for retrieving stages that land downwind. Launch from Boca Chica, then put the first stage down somewhere on an islet at the very southern tip of Florida. Float in with your airship, attach some kind of bridle, and winch it right up into the air, then fly back to the launch point.

Unfortunately, it appears that this particular project is dead, and that there's not a lot of development in this area at the moment. But it would be a neat way to do the logistics associated with reusability...
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: IRobot on 12/09/2013 08:30 pm
I know Elon said F9R performed better than expected, but we don't know how much better !

He quoted the engines running at about 85% capacity.  Not sure how exactly that translates to fuel efficiency though.
Less thrust, more gravity losses.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Wetmelon on 12/09/2013 08:36 pm
I know Elon said F9R performed better than expected, but we don't know how much better !

He quoted the engines running at about 85% capacity.  Not sure how exactly that translates to fuel efficiency though.
Less thrust, more gravity losses.

Due to what, the increased fuel mass at each point in the profile?
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Joffan on 12/09/2013 09:15 pm
I know Elon said F9R performed better than expected, but we don't know how much better !

He quoted the engines running at about 85% capacity.  Not sure how exactly that translates to fuel efficiency though.
Less thrust, more gravity losses.

Due to what, the increased fuel mass at each point in the profile?

Essentially, higher thrust reduces gravity losses because of quicker ascent. More time spent fighting gravity means more propellant used just to "hold the rocket up".
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: TrevorMonty on 12/09/2013 10:15 pm
Does anybody know how much of a fuel saving the +15% increase in thrust would result in.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: macpacheco on 12/10/2013 04:32 am
I know Elon said F9R performed better than expected, but we don't know how much better !

He quoted the engines running at about 85% capacity.  Not sure how exactly that translates to fuel efficiency though.

85% capacity in which point ?
Most rockets (I believe F9R included) must throttle down around Maximum Dynamic pressure, and afterwards can throttle back up again.

Did his statement pointed to SES-8 launch using only 85% or less of available thrust all the way through the launch ? Given the resulting 80000x300 Km orbit, this would be nothing short of astonishing.

If the engines were limited at 85% all the way, increasing to 100% should reduce fuel utilization by more than 15%, given a significant reduction in time spent at lower speeds (consider how much fuel is "wasted" just holding the rocket against gravity from clearing the tower and accelerating to Mach 2 when rockets begin to perform very efficiently), I'm no rocket scientist/engineer, but it's entirely possible the fuel savings at least 20% given the profile is cumulative (speed is integral of acceleration, simplifying to a linear acceleration and 85% to 100% thrust resulting in the same proportional acceleration the extra fuel spent over time is compensated by a squared gain in distance over time, and total time for the same distance is also less). Even with the throttle limitation around MaxQ, still over 20% gains possible (given the F9R is very slender, it probably requires less throttle down than other rockets, less cross section exposed to the wind).

Sorry for the convoluted through process, 20 years since I took Physics and Calculus, explaining the through process might be useful for others, and I'm unsure of lots of aspects.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: cleonard on 12/10/2013 04:47 am
Rocket engines are designed for a specific thrust.  It's generally known as 100%.  Now after they are actually built, tested, and flown it is often found that they have some extra reserve preformance.  The Space Shuttle main engines were this way.  Later in the program they would run at 104% with the abort option of 109%. 

Elon's comment indicates that SpaceX thinks that the Merlin 1D can run up to 115%.   To make maximum use the rocket would need to grow by that same 15%.   Without changing the rocket it only gets you a little extra performance.   You get a little less gravity losses because the rocket can climb out faster and burn out sooner.  It also helps a lot with an engine out.   Since 9 engines at 100% is actailly slightly less than 8 at 115% you have great engine out capability.

A oversimplified first order approximation would be the stage burns out 15% sooner.  If I remember correctly the first stage runs for about 180 seconds.  At 115% fuel use it would be 154 seconds.  That cuts 9.8 * 27 seconds or 264 m/s of gravity loss.  It's actually less since the first stage throttles some at the end.  Maybe 250 m/s.  That's not insignificant.  A good use might be adding some more fuel to the second stage and reducing the staging velocity to make recovery easier..
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: QuantumG on 12/10/2013 05:11 am
To reiterate what he actually said:

Quote from: Elon Musk
I'm really happy with this rocket design. It's an incredibly capable vehicle. It's actually one of the biggest rockets in the world, it's worth noting, at about 1.3 million pounds of thrust, and we're only actually operating the engines at about 85% of their potential. Down the road, in future missions, we anticipate being able to crank them up to their full thrust capability, which would give about 165,000 pounds of sea-level thrust per engine. Anyway, it really is something that is, I think, going to serve really well for the commercial launch market, for government satellites and for Dragon, both crew and cargo.  I believe its inherent reliability potential is better than any other rocket in the world. It will be up to us to show that it lives up to that reliability potential.

http://shitelonsays.com/transcript/spacex-ses-8-pre-launch-conference-2013-11-24

I'm not sure why there's any need to "interpret" what he said.. he did use numbers.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: beancounter on 12/10/2013 07:01 am
To reiterate what he actually said:

Quote from: Elon Musk
I'm really happy with this rocket design. It's an incredibly capable vehicle. It's actually one of the biggest rockets in the world, it's worth noting, at about 1.3 million pounds of thrust, and we're only actually operating the engines at about 85% of their potential. Down the road, in future missions, we anticipate being able to crank them up to their full thrust capability, which would give about 165,000 pounds of sea-level thrust per engine. Anyway, it really is something that is, I think, going to serve really well for the commercial launch market, for government satellites and for Dragon, both crew and cargo.  I believe its inherent reliability potential is better than any other rocket in the world. It will be up to us to show that it lives up to that reliability potential.

http://shitelonsays.com/transcript/spacex-ses-8-pre-launch-conference-2013-11-24

I'm not sure why there's any need to "interpret" what he said.. he did use numbers.

I like the last sentence.  "It will be up to us ...",   and earlier concerning a force for change in their competitors, that already seems to be happening, not entirely due to SpaceX but EADS has released a restructuring program cutting costs (and jobs of course) by significant numbers. 
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: RigelFive on 12/10/2013 07:16 am
To reiterate what he actually said:

Quote from: Elon Musk
I'm really happy with this rocket design. It's an incredibly capable vehicle. It's actually one of the biggest rockets in the world, it's worth noting, at about 1.3 million pounds of thrust, and we're only actually operating the engines at about 85% of their potential. Down the road, in future missions, we anticipate being able to crank them up to their full thrust capability, which would give about 165,000 pounds of sea-level thrust per engine. Anyway, it really is something that is, I think, going to serve really well for the commercial launch market, for government satellites and for Dragon, both crew and cargo.  I believe its inherent reliability potential is better than any other rocket in the world. It will be up to us to show that it lives up to that reliability potential.

http://shitelonsays.com/transcript/spacex-ses-8-pre-launch-conference-2013-11-24

I'm not sure why there's any need to "interpret" what he said.. he did use numbers.
;D
Ohhh man my ribs hurt.  That is a really funny/awesome website!!!
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: macpacheco on 12/10/2013 10:01 am
Rocket engines are designed for a specific thrust.  It's generally known as 100%.  Now after they are actually built, tested, and flown it is often found that they have some extra reserve preformance.  The Space Shuttle main engines were this way.  Later in the program they would run at 104% with the abort option of 109%. 

Elon's comment indicates that SpaceX thinks that the Merlin 1D can run up to 115%.   To make maximum use the rocket would need to grow by that same 15%.   Without changing the rocket it only gets you a little extra performance.   You get a little less gravity losses because the rocket can climb out faster and burn out sooner.  It also helps a lot with an engine out.   Since 9 engines at 100% is actailly slightly less than 8 at 115% you have great engine out capability.

A oversimplified first order approximation would be the stage burns out 15% sooner.  If I remember correctly the first stage runs for about 180 seconds.  At 115% fuel use it would be 154 seconds.  That cuts 9.8 * 27 seconds or 264 m/s of gravity loss.  It's actually less since the first stage throttles some at the end.  Maybe 250 m/s.  That's not insignificant.  A good use might be adding some more fuel to the second stage and reducing the staging velocity to make recovery easier..

Ok, now we're talking. Considering reusability, running at 115% could have thermal stress issues and other things, 100% to 115% very different than 85% to 100% ! So it might only be use to use that in engine out situation (perhaps for 2nd stage, since no plans to reuse for now).

Thanks for the important clarification.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Nomadd on 12/10/2013 11:34 am
I don't think that the term "potential" means they can just step on the gas pedal harder with existing engines, but that they have the potential to be upgraded to 165,000.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: IRobot on 12/10/2013 01:01 pm
To reiterate what he actually said:

Quote from: Elon Musk
I'm really happy with this rocket design. It's an incredibly capable vehicle. It's actually one of the biggest rockets in the world, it's worth noting, at about 1.3 million pounds of thrust, and we're only actually operating the engines at about 85% of their potential. Down the road, in future missions, we anticipate being able to crank them up to their full thrust capability, which would give about 165,000 pounds of sea-level thrust per engine. Anyway, it really is something that is, I think, going to serve really well for the commercial launch market, for government satellites and for Dragon, both crew and cargo.  I believe its inherent reliability potential is better than any other rocket in the world. It will be up to us to show that it lives up to that reliability potential.

http://shitelonsays.com/transcript/spacex-ses-8-pre-launch-conference-2013-11-24

I'm not sure why there's any need to "interpret" what he said.. he did use numbers.
I think Elon likes to play with us by given incomplete information :)

When he talks about 85% and "full thrust capability" is he using the design requirement as the 100% reference?

Looking at their site, they advertise 147,000 lbf per engine at sea level. That is 89%, close to the 85% mark.

So the current F9 at 147,000 lbf seems to be the 100% rated and the future upgrades will enable a jump to 112%.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Garrett on 12/10/2013 04:06 pm
Bringing this over from the Grasshopper thread as it would have been off-topic:
If 2 out of 3 launches uses a recovered 1st stage, they only need to build 7 stages a year to support a 21 core a year launch rate which should be with in their current manufacturing capablities. No need to build another factory which is another big saving.
Their current factory capability is already being ramped up to 40 v1.1 cores per year.
Elon expects "without any miracles" a launch rate of 20 per year (10 F9 and 10 FH), which works out at 40 cores per year.

Recovery, if they succeed, may allow them to continue to sell flights on F9 and FH, while developing and building another more capable rocket using their current factory.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: kirghizstan on 12/10/2013 05:05 pm
Not to be too technical but...

85/100% is not the same as 100/115%. 

While it is close there is a difference so if Elon is saying 85/100% then can we agree to use his numbers going forward. 

even if they were designed to the 85% number but it turned out that they did the 100% number these are the numbers SpaceX is using. 

Math Nazi signing off
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: cleonard on 12/10/2013 06:05 pm
When engineering says that we should be able to get another 15%, management hears "we were only running at 85%."
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Owlon on 12/10/2013 06:11 pm
When engineering says that we should be able to get another 15%, management hears "we were only running at 85%."

To a large degree, Elon is both engineering and management. Its a pretty safe bet that he knows the difference between 85/100 and 100/115.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: oldAtlas_Eguy on 12/10/2013 06:12 pm
I think Elon is thinking way ahead of us about the needs to do US reusable. By going to 165klbf and stretching the US tank size the payload loss for making the US and 1st stage can be mitigated. Allowing for F9R (full reusable) to have a 10+mt payload, enough capability to meet all current customers requirements even SpaceX's Dragon and DragonRider.

BTW a 15% increase can mean for a non reusable FHwCF(with Cross-Feed) with stretched US tanks a 60mt max payload.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: macpacheco on 12/10/2013 06:57 pm
To reiterate what he actually said:

Quote from: Elon Musk
I'm really happy with this rocket design. It's an incredibly capable vehicle. It's actually one of the biggest rockets in the world, it's worth noting, at about 1.3 million pounds of thrust, and we're only actually operating the engines at about 85% of their potential. Down the road, in future missions, we anticipate being able to crank them up to their full thrust capability, which would give about 165,000 pounds of sea-level thrust per engine. Anyway, it really is something that is, I think, going to serve really well for the commercial launch market, for government satellites and for Dragon, both crew and cargo.  I believe its inherent reliability potential is better than any other rocket in the world. It will be up to us to show that it lives up to that reliability potential.

http://shitelonsays.com/transcript/spacex-ses-8-pre-launch-conference-2013-11-24

I'm not sure why there's any need to "interpret" what he said.. he did use numbers.
I think Elon likes to play with us by given incomplete information :)

When he talks about 85% and "full thrust capability" is he using the design requirement as the 100% reference?

Looking at their site, they advertise 147,000 lbf per engine at sea level. That is 89%, close to the 85% mark.

So the current F9 at 147,000 lbf seems to be the 100% rated and the future upgrades will enable a jump to 112%.

1 - This might not be a firm thing (remember hunt for the red october, 110% of the reactor possible but not recomendable) ! This extra thrust might be exploited a little bit at a time
2 - Elon needs to contend with ITAR and competitive issues, so some obfuscation might be by design instead of by a sadistic feelings
3 - I learnt with a very successful Brazilian software developer, always under promise and over deliver ! Leave yourself room for breathing. The only reason to promise with no safety margin is if you'll loose a very important deal in consequence, SpaceX right now has performance to spare, having a spotless 2014 would put them on par safety wise with ULA (about 20 launches failing only a single secondary payload).
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: TrevorMonty on 12/10/2013 10:03 pm
Wording is important. Would you buy an engine that runs at 85% of its tested rating or an engine that runs at 100% of its tested rating but can give 115% if need be.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: cuddihy on 12/11/2013 01:34 am
That assumes a fixed market for launches. In reality if a re-useable launch profile costs 1/4 as much as max performance (for only 30% less payload), payload size trend will move that direction rapidly.

There's only so fast it can move.  Customers launching clusters of satellites per launch (like Iridium) could just launch fewer per shot.  But if the customer is launching a single large satellite (like, say, the SES-8 and upcoming Thaicom launches), cutting 30% off the weight isn't something that can be reasonably done very far into the design process --- and the lead times for that are pretty long.

Lead times for their manifest are currently much longer than satellite build time. They've said they're going to ramp up rapidly...they've been saying that for nearly 5 years now...
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: macpacheco on 12/11/2013 03:47 pm
Critical point in the process right now is building space to integrate at least 2 payloads + their F9R's in the Cape (3 ideal) simultaneously.

Now that the Rocket design is 99% frozen (still have the legs, any further tweaks must be such that they can be undone say for DoD launches, even removing the legs if they customer pays more for a fully expendable launch), they might not need to fully analyze data from prior launches before the next, so 10 days to refurbish the pad, static fire, 5 days, launch, that's two launches per month with a single pad, considering the west coast facilities are scheduled to launch fairly few times, I'd say they can easily do 24 launches/year (with the west coast facilities just compensating for delays in the cape + any idle time due to no customers with payload ready before the next scheduled launch, hurricane season, ...), ideally create a pipeline of rockets + payloads, launching as soon as the pad is ready.

Once the static fire is shown to be unnecessary (today it's still important), could they simply add a few more seconds of hold before release and kill the static fire (speculate this will happen in 2014).
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lar on 12/11/2013 03:52 pm
Critical point in the process right now is building space to integrate at least 2 payloads + their F9R's in the Cape (3 ideal) simultaneously.

Now that the Rocket design is 99% frozen (still have the legs, any further tweaks must be such that they can be undone say for DoD launches, even removing the legs if they customer pays more for a fully expendable launch), they might not need to fully analyze data from prior launches before the next, so 10 days to refurbish the pad, static fire, 5 days, launch, that's two launches per month with a single pad, considering the west coast facilities are scheduled to launch fairly few times, I'd say they can easily do 24 launches/year (with the west coast facilities just compensating for delays in the cape + any idle time due to no customers with payload ready before the next scheduled launch, hurricane season, ...), ideally create a pipeline of rockets + payloads, launching as soon as the pad is ready.

Once the static fire is shown to be unnecessary (today it's still important), could they simply add a few more seconds of hold before release and kill the static fire (speculate this will happen in 2014).

What are the pad tasks that drive 10 day refurbishment cycles? I would expect that if manifest density increases there will be work to shorten that time. Either by speeding up tasks or by eliminating them (for example eliminate umbilical replacement by changing to flame resistant umbilicals or what have you). 

I would also expect to see more flexible ordering/sequencing, that is, if a particular vehicle has an issue, it gets bumped behind the next one so as not to delay the whole manifest.... that DEFINITELY requires lots of workspace though!
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Jim on 12/11/2013 04:57 pm

1.  Now that the Rocket design is 99% frozen

2.   that's two launches per month with a single pad

3.  Once the static fire is shown to be unnecessary (today it's still important), could they simply add a few more seconds of hold before release and kill the static fire (speculate this will happen in 2014).

1. Based on what?

2.  Not doable, it takes more to assemble the vehicle and payload

3. No, they would not extend hold down, if static fire is eliminated.  That makes no sense
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lar on 12/11/2013 05:20 pm
2.  Not doable, it takes more to assemble the vehicle and payload

Jim.. suppose you were charged with increasing the flight rate per pad.

What would you change? Assume unlimited budget for the sake of argument, then assume something reasonable...

Would you change the vehicle? the pad itself? add more staging areas so multiple vehicles could be in integration at the same time? what?
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Jim on 12/11/2013 05:31 pm
add more staging areas so multiple vehicles could be in integration at the same time? what?

That
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Jim on 12/11/2013 05:33 pm
they might not need to fully analyze data from prior launches before the next,

That is not going to happen
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lar on 12/11/2013 05:51 pm
Jim I think your quotes are garbled a bit...

I'll ask again, assume you have a clean sheet and unlimited budget, how would you get the flow up? What would you do differently? You know so much and we know so little, indulge us with some speculation instead of just saying no...
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: dcporter on 12/11/2013 06:41 pm
add more staging areas so multiple vehicles could be in integration at the same time? what?

That

Jim would do that.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lar on 12/11/2013 06:57 pm
add more staging areas so multiple vehicles could be in integration at the same time? what?

That

Jim would do that.

ah, and here I thought it was garbled... it was just terseness! :)
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Tass on 12/11/2013 10:09 pm
I'll just point out that the post Jim shot down actually suggested exactly what Jim said he'd do to increase flight rate.

Critical point in the process right now is building space to integrate at least 2 payloads + their F9R's in the Cape (3 ideal) simultaneously.

Not doable, it takes more [time] to assemble the vehicle and payload
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: beancounter on 12/12/2013 12:35 am
add more staging areas so multiple vehicles could be in integration at the same time? what?

That

Jim would do that.

ah, and here I thought it was garbled... it was just terseness! :)

No, Jim was being concise.  He generally doens't waste words.  :)
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lars_J on 12/12/2013 12:39 am
We need to start a collection for Jim so he can afford a better internet service provider. His current one apparently charges per word uploaded. ;D
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lar on 12/12/2013 01:08 am
We need to start a collection for Jim so he can afford a better internet service provider. His current one apparently charges per word uploaded. ;D
I already tried to buy some stuff from him on eBay but whenever I check there's not anything I'm keen on.

Back to the topic, I think multiple processing areas helps. But what else can be done? Jim, how would you reduce dwell time on the pad itself?
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Garrett on 12/12/2013 01:25 pm
Back to the topic, I think multiple processing areas helps. But what else can be done? Jim, how would you reduce dwell time on the pad itself?
Trying to follow the conversation, but not easy to understand the last question without specifics.
 1. How would you define pad "dwell time" ?
 2. What is the current order of magnitude for Falcon dwell times? in comparison with Atlas, Delta?
 3. Is dwell time (however it's defined) actually relevant at the moment? (i.e. remind me/us what launch rate is being hoped for here and for when).

Cheers!
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: oldAtlas_Eguy on 12/12/2013 02:53 pm
Jim is correct that increasing square footage for the HIF to be able to process 2 or more F9's or F9R's in about 2 week or less intervals can easily get the launch rate to about 2 or more a month. From previous flows the payload was not mated until the last 2 weeks of the flow after the F9 was fully processed which takes about 2 weeks. So by doubling the HIF floor space size and almost doubling the manpower without changing any of the process tasks or even not eliminating any, can easily double your launch rate on a single pad.

The problem is that a launch or launch attempt stops work on the follow-on vehicle during the launch day. So you lose a few days of processing the next F9/F9R if the next F9/F9R is close to the pad as in the current HIF arrangement. A facility farther away that does not have to be evacuated during launch ops where a fully assembled F9/F9R is then transported to the closer HIF after the launch. The work interruption would then be reduced to a matter of hours instead of several days.

Why do you think the VAB was designed with four assembly bays?
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Garrett on 12/12/2013 03:37 pm
So, if I dare use an airplane analogy :
 - multiple prep areas like the multiple gates of an airport terminal
 - pads located away from prep areas, similar to flight paths never going over the airport itself
 - efficient pad access, like an efficient airport taxiway
 - a queue system where the first come is the first served*

* my naive idea. I'll stop at that. No more air travel analogies, I promise.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Lar on 12/12/2013 03:39 pm
Back to the topic, I think multiple processing areas helps. But what else can be done? Jim, how would you reduce dwell time on the pad itself?
Trying to follow the conversation, but not easy to understand the last question without specifics.
 1. How would you define pad "dwell time" ?
 2. What is the current order of magnitude for Falcon dwell times? in comparison with Atlas, Delta?
 3. Is dwell time (however it's defined) actually relevant at the moment? (i.e. remind me/us what launch rate is being hoped for here and for when).

Cheers!
1. the total time the pad is not available to a different vehicle
2. it appears to be around a week to 10 days per other posts in this thread and others
3. to get to 2 a month per pad, it's not relevant. To get to once a day per pad it would be hugely relevant. I think even once a week per pad would require shaving that 7-10 days down to more like 3-5

I think your airport analogy is apt... I think we will someday see queue systems where launches bump each other based on who is ready to go.. .airports now have a precedence order for takeoff that is partly schedule driven and partly driven by which planes are ready and which are still at the gate.  (if you use flighttracker sites like I do you can see the predicted takeoff times shift with slippage in gate departures even hours ahead of the inbound flight arrival that will be the aircraft for the outbound)
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: Elmar Moelzer on 12/12/2013 03:45 pm
1. the total time the pad is not available to a different vehicle
2. it appears to be around a week to 10 days per other posts in this thread and others
3. to get to 2 a month per pad, it's not relevant. To get to once a day per pad it would be hugely relevant. I think even once a week per pad would require shaving that 7-10 days down to more like 3-5
I think that processing times and pad dwelling times will be reduced as experience of the crew with the launch vehicle increases and the initial quirks with it are resolved. After all, the F91.1 has only seen two launches so far. It is hard to deduce the future from so little data. Once things become more routine, pad times will go down. Of course they will go up again once they start reusing stages until that becomes routine as well. This will take a couple of years, I guess.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: macpacheco on 12/13/2013 12:39 am
I'll just point out that the post Jim shot down actually suggested exactly what Jim said he'd do to increase flight rate.

Critical point in the process right now is building space to integrate at least 2 payloads + their F9R's in the Cape (3 ideal) simultaneously.

Not doable, it takes more [time] to assemble the vehicle and payload

With the extra info Jim gave, it looks like the only bottleneck is one extra building, no extra launch pads needed.
With another processing facility, as long as rocket/payload arrives right after the previous launch holding that building (pipeline kept full), launch rates could be doubled. And that's not including any streamlining that becomes doable on each launch.

My assertion F9R design is 99% frozen is based on lack of anything suggesting there are any major changes worth doing that would change the manufacturing process much. Landing legs is already planned in the design (we could say the design allows for F9R with and without the legs), plus some minor changes to increase control attitude during re-entry. Of course, only insiders really know what's on Elon's mind. I'm not an insider in any measure.

Thanks for the expert information Jim.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: joek on 12/14/2013 09:24 pm
Jim is correct that increasing square footage for the HIF to be able to process 2 or more F9's or F9R's in about 2 week or less intervals can easily get the launch rate to about 2 or more a month. From previous flows the payload was not mated until the last 2 weeks of the flow after the F9 was fully processed which takes about 2 weeks. So by doubling the HIF floor space size and almost doubling the manpower without changing any of the process tasks or even not eliminating any, can easily double your launch rate on a single pad.

The problem is that a launch or launch attempt stops work on the follow-on vehicle during the launch day. So you lose a few days of processing the next F9/F9R if the next F9/F9R is close to the pad as in the current HIF arrangement. A facility farther away that does not have to be evacuated during launch ops where a fully assembled F9/F9R is then transported to the closer HIF after the launch. The work interruption would then be reduced to a matter of hours instead of several days.

Why do you think the VAB was designed with four assembly bays?

Good points, and I'd agree that a much higher launch rate seems a reasonable goal based on the evidence (assuming manufacturing and test or pad R&R are not the limiting factors).

Note that the SES-8 static fire test without payload was Nov 21; the first launch attempt with payload was Nov 25.  I've no idea of the time breakdown, but that suggests final payload integration, checkout, and rollout is on the order of a few days (?).

Also, additional facilities should not only be farther away from LC-40, but far enough that other range activities do not unduly interrupt or delay LV or payload processing.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: TrevorMonty on 12/17/2013 06:03 am
With renewed discussions on the lunar ice threads I was wondering if a reusable 2nd stage (LOX-LH2 fueled version) for FH could deliver a Dragon to L1 or a lunar orbit, partially refuel and return to earth.  Trip scenario would be
1) Earth to L1, passenger or cargo transfer to lunar lander.
2) 2nd stage with Dragon still attached would partially refuel using lunar supplied fuel.
3) Return passengers would transfer from lander to Dragon
4) Dragon would separate from 2nd stage just before earth re entry. 2nd stage may have to do a burn to slow its re entry speed.

This may be OT but can't find a home for it else where.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: TrevorMonty on 12/18/2013 06:41 pm
I was more interested in whether a reusable 2nd stage would be technically possible for this mission.
There 's a few lunar ice threads available for ISRU discussions.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: KelvinZero on 12/19/2013 07:09 am
Oops sorry, I probably misread your post. Thought you were suggesting SpaceX change to hydrogen to allow ISRU. I wasn't trying to turn the conversation to ISRU, but pointing out there is more CO there than water.

... I meant to just say we could keep talking about a methane/hydrocarbon fueled stage and didn't need to hypothesize a change to hydrogen.
Title: Re: Musk lays out plans for reusability of the Falcon 9 rocket
Post by: TrevorMonty on 12/19/2013 07:38 am
No problem KelvinZero