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SpaceX Vehicles and Missions => SpaceX Reusability => Topic started by: Mader Levap on 12/25/2015 09:07 pm

Title: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Mader Levap on 12/25/2015 09:07 pm
Some guy noticed something verrry interesting...

https://www.instagram.com/p/_rxv0Unse7/?taken-by=alternativeauto_2.0

Note no legs, as expected.
Title: Re: Stage transported
Post by: meekGee on 12/25/2015 09:19 pm
Some guy noticed something verrry interesting...

https://www.instagram.com/p/_rxv0Unse7/?taken-by=alternativeauto_2.0

Note no legs, as expected.

And a happy new home at 39A
Title: Re: Stage transported
Post by: brettreds2k on 12/26/2015 12:26 am
Very cool, have any pictures of the landing pad surfaced that show how that faired from the landing?
Title: Re: Stage transported
Post by: Kabloona on 12/26/2015 02:33 am
Some guy noticed something verrry interesting...

https://www.instagram.com/p/_rxv0Unse7/?taken-by=alternativeauto_2.0

Note no legs, as expected.

Thanks, and here's a comment posted on that video from an apparent SpaceXer:

Quote
[email protected]_2.0, Thanks for posting this video, I'd get canned for posting it. We are on top on the world right now and Im proud as hell of the great team I work with, but I would like for you to take a moment to consider all of the long hours, late nights, missed birthdays and disappointed loved ones went into this launch and landing. It's been a hell of a year. Go SpaceX Go Falcon9

No doubt it's been a brutal 6 months.
Title: Re: Stage transported
Post by: shuttlefan on 12/26/2015 02:43 am
What are they going to do with it at Pad A?
Title: Re: Stage transported
Post by: Kabloona on 12/26/2015 02:48 am
What are they going to do with it at Pad A?

Use it to fit check all the pad connections, and do a static fire on the pad.
Title: Re: Stage transported
Post by: Lars-J on 12/26/2015 02:48 am

What are they going to do with it at Pad A?

Fit checks and potential hot fire.
Title: Re: Stage transported
Post by: shuttlefan on 12/26/2015 03:02 am
So they plan on actually erecting it on the pad?!
Title: Re: Stage transported
Post by: macpacheco on 12/26/2015 03:12 am
So they plan on actually erecting it on the pad?!
Yes, a normal (or longer duration) static fire to perform a full shakedown of the pad.
Make sure everything is great, to perhaps do the next CRS launch on that pad. I'm assuming CRS missions will be done at LC39A to offload LC40 (it's been said that govt launches and FH launches go to LC39A).
Title: Re: Stage transported
Post by: shuttlefan on 12/26/2015 03:26 am
So they plan on actually erecting it on the pad?!
Yes, a normal (or longer duration) static fire to perform a full shakedown of the pad.
Make sure everything is great, to perhaps do the next CRS launch on that pad. I'm assuming CRS missions will be done at LC39A to offload LC40 (it's been said that govt launches and FH launches go to LC39A).

Well it says the next CRS launch is targeted Feb.7th from Pad 40 unless they plan on moving it to Pad 39-A.
Title: Re: Stage transported
Post by: macpacheco on 12/26/2015 04:07 am
So they plan on actually erecting it on the pad?!
Yes, a normal (or longer duration) static fire to perform a full shakedown of the pad.
Make sure everything is great, to perhaps do the next CRS launch on that pad. I'm assuming CRS missions will be done at LC39A to offload LC40 (it's been said that govt launches and FH launches go to LC39A).

Well it says the next CRS launch is targeted Feb.7th from Pad 40 unless they plan on moving it to Pad 39-A.

Makes sense. The static fire on LC39A might be done after Feb 7th anyway. But once the pad is operational, then I expect it will be used for CRS missions to take advantage of its own processing facilities allowing for parallel preparation of 3 launches simultaneously (LC40, LC39A and Vandy).
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Chris Bergin on 12/26/2015 01:17 pm
Thread renamed to something descriptive. Apparently it's on another thread too, but I think it deserves a standalone at least.

This will be the rolled out for a Static Fire in 2016.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: FishInferno on 12/26/2015 02:21 pm
Why no legs?
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: shuttlefan on 12/26/2015 02:24 pm
So they plan on actually erecting it on the pad?!
Yes, a normal (or longer duration) static fire to perform a full shakedown of the pad.
Make sure everything is great, to perhaps do the next CRS launch on that pad. I'm assuming CRS missions will be done at LC39A to offload LC40 (it's been said that govt launches and FH launches go to LC39A).

Well it says the next CRS launch is targeted Feb.7th from Pad 40 unless they plan on moving it to Pad 39-A.

Makes sense. The static fire on LC39A might be done after Feb 7th anyway. But once the pad is operational, then I expect it will be used for CRS missions to take advantage of its own processing facilities allowing for parallel preparation of 3 launches simultaneously (LC40, LC39A and Vandy).

Ok great thanks for the info!
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Jakusb on 12/26/2015 02:25 pm

Why no legs?
Current assumption: they have no easy way to fold them back.
Probably easier to just detach, inspect thoroughly.
Also, not needed for static fire at LC39A.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: rsdavis9 on 12/26/2015 02:40 pm
Anybody have an explanation of the soot patterns on the rocket? I can see the pattern for where the legs
 were but why does it stop right above the legs and then continues near the top?
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Dante80 on 12/26/2015 02:44 pm
Current speculation is that the lower end either uses a different paint that results in some short of ablation, or that the soot mark stops at the end of the LOX tank (which is very cold/has ice and soot does not stick there).

For reference, we saw the same exact soot pattern in the CRS-6 landing attempt.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: rsdavis9 on 12/26/2015 03:46 pm
OK oxygen tank and frost makes sense but the soot reappears near the top also where the tank still is. Unless the lox isn't sloshing that far up?
Title: Re: Stage transported
Post by: Robotbeat on 12/26/2015 03:47 pm
Very cool, have any pictures of the landing pad surfaced that show how that faired from the landing?
Here:
https://twitter.com/elonmusk/status/679145544673923072

Seems to have fared very well, actually. No damage is visible in this video, so any damage would have to be relatively minor.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: FishInferno on 12/26/2015 03:50 pm
OK oxygen tank and frost makes sense but the soot reappears near the top also where the tank still is. Unless the lox isn't sloshing that far up?

The Lox is all in the bottom of the tank, so the top will not be as cold.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: oldAtlas_Eguy on 12/26/2015 04:18 pm
Well they are already doing the first fit check. Is the turn around pad area large enough?
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Dante80 on 12/26/2015 05:07 pm
OK oxygen tank and frost makes sense but the soot reappears near the top also where the tank still is. Unless the lox isn't sloshing that far up?

That soot is probably from the second stage engine start. Which also explains the reason its not that defined...(and also the fact that only part of the lox tank area in the middle remains soot free, since at SEP a good portion of the LOX is already expended, thus not cooling the upper lox tank walls - the rest soot covered part is actually the interstage).
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Robotbeat on 12/26/2015 05:12 pm
Awesome. That stage has been to hell and back, a seasoned vehicle.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Dante80 on 12/26/2015 05:13 pm
Great photoshop skills. There is no way in hell Elon would leave the soot there though...the guy does not permit extending the SpaceX logo to the LOX tank so that it doesn't get obscured by ice, I don't think he'd ever want to launch a dirty looking rocket.  :D

Personally, I'd love to see it flying like that (IF of course soot doesn't affect performance or other attributes of the mission). It looks seasoned and meaning business. A real working vehicle, the Lada Niva of rocketry...C:
 
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: friendly3 on 12/26/2015 05:51 pm
Moved my post to a more appropriate thread.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: mme on 12/26/2015 10:07 pm
OK oxygen tank and frost makes sense but the soot reappears near the top also where the tank still is. Unless the lox isn't sloshing that far up?

That soot is probably from the second stage engine start. Which also explains the reason its not that defined...(and also the fact that only part of the lox tank area in the middle remains soot free, since at SEP a good portion of the LOX is already expended, thus not cooling the upper lox tank walls - the rest soot covered part is actually the interstage).
Yup, it definitely gets "smoked" by the second stage:
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: meekGee on 12/26/2015 10:21 pm
OK oxygen tank and frost makes sense but the soot reappears near the top also where the tank still is. Unless the lox isn't sloshing that far up?

That soot is probably from the second stage engine start. Which also explains the reason its not that defined...(and also the fact that only part of the lox tank area in the middle remains soot free, since at SEP a good portion of the LOX is already expended, thus not cooling the upper lox tank walls - the rest soot covered part is actually the interstage).
Yup, it definitely gets "smoked" by the second stage:

Is there something sticking out of the first stage on the bottom? It can't be a grid fin, can it?

EDIT: I've just replayed the stage separation sequence over and over, and it's very hard to make heads and tails from it....   Things are happening very fast, I think I see the first stage attitude jets firing, but it could just be lens flare, I definitely can't tell which parts of the first stage are exposed to the flame, or home much sooty dark flame there is prior to the plume stabilizing.   

I wonder if the soot pattern on the first stage is symmetrical all around, or whether it has a preferential side.

Even a small angle would have caused the soot deposition on the first stage to be single sided, IF its source was the upper stage burn.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: mme on 12/26/2015 10:34 pm
...
Yup, it definitely gets "smoked" by the second stage:
Is there something sticking out of the first stage on the bottom? It can't be a grid fin, can it?
I don't think so, if you watch the video all sorts of "stuff" is streaking out past the bell before and during ignition.  I think it's just some flotsam being illuminated during ignition.

Edit: Corrected "streaking," but I think the nitrogen jet makes even more sense...
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: MarsInMyLifetime on 12/26/2015 11:58 pm
There are nitrogen gas RCS thrusters on the interstage; in the landing videos, you can see them venting after the landing. In the last barge landing, one of the sideways thrusters is clearly doing all it can to keep the stage upright, and the jet is coming from very nearly the same location and tangent as this apparition.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Kabloona on 12/27/2015 12:23 am
There are nitrogen gas RCS thrusters on the interstage; in the landing videos, you can see them venting after the landing. In the last barge landing, one of the sideways thrusters is clearly doing all it can to keep the stage upright, and the jet is coming from very nearly the same location and tangent as this apparition.

Yes, it's a nitrogen thruster plume.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: meekGee on 12/27/2015 01:35 am
There are nitrogen gas RCS thrusters on the interstage; in the landing videos, you can see them venting after the landing. In the last barge landing, one of the sideways thrusters is clearly doing all it can to keep the stage upright, and the jet is coming from very nearly the same location and tangent as this apparition.

Yes, it's a nitrogen thruster plume.

That's what I thought.  So the stage is already starting to want to turn.

If it turned even a degree, half of it would be "shaded" from the high velocity plume, and if that was the source of the soot, it'd be apparent.

We have a few views of the sooty stage.  Can we tell if it's sooty all around?
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: MarsInMyLifetime on 12/27/2015 03:57 am
Considering that the staging exhaust is both rapidly expanding and also rapidly moving away from the stage, I think the likelihood is far greater that any soot we see anywhere on it was deposited during the many seconds that the stage was enveloped in exhaust while going bottom first into the reentry slipstream. LOX concentration near the drain end of its tank certainly stands out in my mind as the evident agent for the clean line on the cold end of the tank giving way to increased adhesion at the warmer end of the tank. The seaside photos of the crane-supported stage seem to show the same soot distribution we've seen in other pictures. I have a little concern for the exposed components inside the interstage that are washed by the startup exhaust from the second stage engine, but no doubt these are robustly attached and insulated.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: MarsInMyLifetime on 12/27/2015 04:05 am
The photo of the trucked stage clearly shows a flat cap over the end, to which the lifting struts are attached (not a flexible harness, it seems). This would seem to indicate a cap that can be settled onto the top and possibly latched in place remotely (yes, I'm still thinking about safety and necessity for sending workers up there, post-landing, for an operation that needs to be fast and repeatable for future workflows).
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: meekGee on 12/27/2015 05:23 am
The photo of the trucked stage clearly shows a flat cap over the end, to which the lifting struts are attached (not a flexible harness, it seems). This would seem to indicate a cap that can be settled onto the top and possibly latched in place remotely (yes, I'm still thinking about safety and necessity for sending workers up there, post-landing, for an operation that needs to be fast and repeatable for future workflows).

You'd trust the latch to lift the rocket without verifying?  Or do you think they had a remote camera or latch sensors on that lift ring?
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: ugordan on 12/27/2015 11:37 am
More from Shannon Gordon (The only one with footage it seems):

https://www.youtube.com/watch?v=08AO5N0CMKg

https://www.youtube.com/watch?v=CIiY6wC6RDY
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: dcporter on 12/27/2015 02:32 pm
These videos are like the Star Wars TV spots. Not really much new or different in each one but I'm sure gonna watch it and feel a little giddy about the whole thing
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: douglas100 on 12/27/2015 03:25 pm

You'd trust the latch to lift the rocket without verifying?  Or do you think they had a remote camera or latch sensors on that lift ring?

I would think latch sensors would we enough. But however they do it, it would have been well tested by F9R ops at McGregor.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Lee Jay on 12/27/2015 03:37 pm
The photo of the trucked stage clearly shows a flat cap over the end, to which the lifting struts are attached (not a flexible harness, it seems). This would seem to indicate a cap that can be settled onto the top and possibly latched in place remotely (yes, I'm still thinking about safety and necessity for sending workers up there, post-landing, for an operation that needs to be fast and repeatable for future workflows).

I've been up in manlifts thousands of times (literally).  Going up and attaching a lifting system is a 10 minute job, and it's pretty much perfectly safe.  It's done tens of thousands of times every day in construction.

Why make something harder than it has to be?
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: douglas100 on 12/27/2015 03:40 pm

I've been up in manlifts thousands of times (literally).  Going up and attaching a lifting system is a 10 minute job, and it's pretty much perfectly safe.  It's done tens of thousands of times every day in construction.

Thanks for that.

Quote
Why make something harder than it has to be?

Indeed.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Jakusb on 12/27/2015 04:08 pm


I've been up in manlifts thousands of times (literally).  Going up and attaching a lifting system is a 10 minute job, and it's pretty much perfectly safe.  It's done tens of thousands of times every day in construction.

Thanks for that.

Quote
Why make something harder than it has to be?

Indeed.

Maybe people are wondering how one crane can do both...?
I guess this crane has two cables and can operate one cable with man lift independently from the cable that will be attached to the stage..?
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: matthewkantar on 12/27/2015 04:29 pm
I wonder why they went with two 48 wheeled sleds instead of the over-the-road Falcon first stage  rig?

Matthew
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Jakusb on 12/27/2015 04:32 pm

I wonder why they went with two 48 wheeled sleds instead of the over-the-road Falcon first stage  rig?

Matthew
1) transporter likely is in McGreggor or Hawtorn?
2) maybe corners are too much of a challenge for transporter? The last corner for HIF seemed quite sharp.
Anyway clearly they had a good reason...
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: meekGee on 12/27/2015 04:36 pm


I've been up in manlifts thousands of times (literally).  Going up and attaching a lifting system is a 10 minute job, and it's pretty much perfectly safe.  It's done tens of thousands of times every day in construction.

Thanks for that.

Quote
Why make something harder than it has to be?

Indeed.

Maybe people are wondering how one crane can do both...?
I guess this crane has two cables and can operate one cable with man lift independently from the cable that will be attached to the stage..?
No no no...

Two independent parallel cables in close proximity is a recipe for disaster.

I played with cables and cranes a little bit, I would not recommend such a plan.

Crane from one side, man lift at 120 degrees to it, that would be my take.

Or some auto latch, but man, you'd have to make damn sure all the snaps clicked in.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Jakusb on 12/27/2015 04:39 pm



I've been up in manlifts thousands of times (literally).  Going up and attaching a lifting system is a 10 minute job, and it's pretty much perfectly safe.  It's done tens of thousands of times every day in construction.

Thanks for that.

Quote
Why make something harder than it has to be?

Indeed.

Maybe people are wondering how one crane can do both...?
I guess this crane has two cables and can operate one cable with man lift independently from the cable that will be attached to the stage..?
No no no...

Two independent parallel cables in close proximity is a recipe for disaster.

I played with cables and cranes a little bit, I would not recommend such a plan.

Crane from one side, man lift at 120 degrees to it, that would be my take.

Or some auto latch, but man, you'd have to make damn sure all the snaps clicked in.

I have seen it before. Many cranes in the Netherlands use it to lift poles to underneath the hammer block. Poles are then hammered deep into the group for foundation purposes.
As long as you do not lower both cables at the same time, you should be ok..
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Lee Jay on 12/27/2015 04:44 pm


I've been up in manlifts thousands of times (literally).  Going up and attaching a lifting system is a 10 minute job, and it's pretty much perfectly safe.  It's done tens of thousands of times every day in construction.

Thanks for that.

Quote
Why make something harder than it has to be?

Indeed.

Maybe people are wondering how one crane can do both...?

They had a manlift on the pad with the crane.

http://forum.nasaspaceflight.com/index.php?topic=38149.msg1464804#msg1464804
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Lee Jay on 12/27/2015 04:52 pm


I've been up in manlifts thousands of times (literally).  Going up and attaching a lifting system is a 10 minute job, and it's pretty much perfectly safe.  It's done tens of thousands of times every day in construction.

Thanks for that.

Quote
Why make something harder than it has to be?

Indeed.

Maybe people are wondering how one crane can do both...?
I guess this crane has two cables and can operate one cable with man lift independently from the cable that will be attached to the stage..?
No no no...

Two independent parallel cables in close proximity is a recipe for disaster.

It's done all the time.  That's why many larger cranes have a main cable and an auxiliary cable.  I've done it with boom cranes and with bridge cranes.  It's no big deal if you use a little skill.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: meekGee on 12/27/2015 05:00 pm


I've been up in manlifts thousands of times (literally).  Going up and attaching a lifting system is a 10 minute job, and it's pretty much perfectly safe.  It's done tens of thousands of times every day in construction.

Thanks for that.

Quote
Why make something harder than it has to be?

Indeed.

Maybe people are wondering how one crane can do both...?
I guess this crane has two cables and can operate one cable with man lift independently from the cable that will be attached to the stage..?
No no no...

Two independent parallel cables in close proximity is a recipe for disaster.

It's done all the time.  That's why many larger cranes have a main cable and an auxiliary cable.  I've done it with boom cranes and with bridge cranes.  It's no big deal if you use a little skill.
Maybe, but I'd rather not have a man cage and a load on the same boom and right near each other.

I'd have the manlift out-of-line of the boom, and also out-of-swing.

These things can (admittedly  rarely) go south awfully fast.

Especially here when you want both the lift hat and the man cage loose at the same time.  It takes very little for he two cables to start twisting if contact is made.  Then someone releases tension in one cable to try to fix it, and it's off to the races....

Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Dante80 on 12/27/2015 05:24 pm
I wonder why they went with two 48 wheeled sleds instead of the over-the-road Falcon first stage  rig?

Matthew

Maybe it was what they had available at the time.

Also, recovery might be a slightly different process than the way the S1 is normally transported cross-country shrouded from the factory. The distances here are minuscule in comparison.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Lee Jay on 12/27/2015 05:26 pm
Maybe, but I'd rather not have a man cage and a load on the same boom and right near each other.

You would pretty much never do that.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: ugordan on 12/27/2015 05:31 pm
I wonder why they went with two 48 wheeled sleds instead of the over-the-road Falcon first stage  rig?

They already used this before for short site-to-site transport around the Cape. Below, DSCOVR booster being transferred from one of the Hangar buildings to SLC-40.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: rnataraja on 12/27/2015 05:34 pm
Next things on stage are static fire tests and another LEO recovery?
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: AJW on 12/27/2015 05:37 pm
The main cable is pulled to the top.   The cage is raised with no other cables around it.  Once the cage is at the top, the crane moves the cage over the stage and the main cable is lowered and the person in the cage connects the cable to the top of the stage.  The crane now backs up and lowers the man cage.

No, I'm not in construction, but this doesn't appear to be rocket science.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Lee Jay on 12/27/2015 05:54 pm
The main cable is pulled to the top.   The cage is raised with no other cables around it.  Once the cage is at the top, the crane moves the cage over the stage and the main cable is lowered and the person in the cage connects the cable to the top of the stage.  The crane now backs up and lowers the man cage.

No, I'm not in construction, but this doesn't appear to be rocket science.

That's a lot harder than it sounds.  First, you need to have control over where the main cable is (because the lifting spreader bar/attachment rig needs to be over the load center) and the basket (because the humans need to be able to reach all of the attachments) separately.  Second, the lifting rig may be heavier than you might think (it includes the weight of the ball/block, the slings and the bar/rig itself) and thus may compromise the very stringent safety standards for lifting people with a crane.  By the way, those standards often include a pre-lift with the same mass (in the form of weights in the basket) to the same location, and leaving it there for minutes to many minutes, then lowering it back down, unloading the weights, and getting the humans in.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: macpacheco on 12/27/2015 06:14 pm
Next things on stage are static fire tests and another LEO recovery?
Static fire yes.

Another LEO recovery, uncertain. If you take Musk's words at face value the answer would be probably no. But I think that decision will be taken after the static fire results are analysed, if the data is picture perfect, SpaceX could go for some sort of demo mission. Read the transcripts of the conference call right after the launch.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: AJW on 12/27/2015 06:32 pm
The main cable is pulled to the top.   The cage is raised with no other cables around it.  Once the cage is at the top, the crane moves the cage over the stage and the main cable is lowered and the person in the cage connects the cable to the top of the stage.  The crane now backs up and lowers the man cage.

No, I'm not in construction, but this doesn't appear to be rocket science.

That's a lot harder than it sounds.  First, you need to have control over where the main cable is (because the lifting spreader bar/attachment rig needs to be over the load center) and the basket (because the humans need to be able to reach all of the attachments) separately.  Second, the lifting rig may be heavier than you might think (it includes the weight of the ball/block, the slings and the bar/rig itself) and thus may compromise the very stringent safety standards for lifting people with a crane.  By the way, those standards often include a pre-lift with the same mass (in the form of weights in the basket) to the same location, and leaving it there for minutes to many minutes, then lowering it back down, unloading the weights, and getting the humans in.

My uncle owned a crane operation, and while I never got to see him move a multi-million dollar first stage, I did see him move heavy equipment including full size locomotives.  Pun or not, this work is not to be taken lightly.   From your reply, we don't seem to be in disagreement on the likely process, just the level of detail provided.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: dgates on 12/27/2015 11:52 pm
3 questions:
Landed stage empty weight =.  _________
Landed stage residual fuel weight = ________
Landed stage residual LOX weight = ________

Getting rid of the leftover LOX is easy, drain it or simply let it boil off and vent it.
The extra RP1 can readily be drained into trucks.

Could empty landed stage be in the reasonable weight range to be helo lifted? (San Nicholas Island, for example...)
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Lee Jay on 12/27/2015 11:59 pm

Could empty landed stage be in the reasonable weight range to be helo lifted? (San Nicholas Island, for example...)


No way.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: dgates on 12/28/2015 12:17 am

Could empty landed stage be in the reasonable weight range to be helo lifted? (San Nicholas Island, for example...)


No way.

Defend that.  Why not? CH-53K can lift a 35,000lb external load.  How much does an empty landed stage weigh?
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: cscott on 12/28/2015 12:23 am
~25,600kg according to http://spaceflight101.com/spacerockets/falcon-9-v1-1-f9r/

That's 56,320lbs.

EDIT: And it should be noted that the CH-53K does not practically exist yet, and the CH-53E (the actual operational helicopter) can only lift 14,500kg.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: macpacheco on 12/28/2015 12:28 am
Defend that.  Why not? CH-53K can lift a 35,000lb external load.  How much does an empty landed stage weigh?
A simple google search suggests the empty first stage is around 20 tons.
That's 44,000lb, and it might be a little heavier including landing legs for instance.
Probably around 50k lbs.
Just some food for thought.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: dgates on 12/28/2015 01:10 am
Ok, I give!  Thanks! :).

But.... If one pulled a few engines.......
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: John Alan on 12/28/2015 01:42 am
Ok, I give!  Thanks! :).

But.... If one pulled a few engines.......

Nah...  ;)
If SpaceX decides to start air freighting S1 stages anywhere...
It will involve refueling
...and suborbital hops
 :o   ;D
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Zed_Noir on 12/28/2015 02:41 am
~25,600kg according to http://spaceflight101.com/spacerockets/falcon-9-v1-1-f9r/

That's 56,320lbs.

EDIT: And it should be noted that the CH-53K does not practically exist yet, and the CH-53E (the actual operational helicopter) can only lift 14,500kg.

Normally you couldn't used 2 helos. The F9 core is so long that you can have a helo lifted from each end. But while possible, doesn't seem very practical or cheap.

IIRC the CH-53K have the same external lift capability as the CH-53E due to using the same external cargo handling system.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: JAFO on 12/28/2015 03:45 am
Ok, I give!  Thanks! :) .

But.... If one pulled a few engines.......

What if they used unladen swallows to lift it?
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Ludus on 12/28/2015 04:15 am
Ok, I give!  Thanks! :) .

But.... If one pulled a few engines.......

What if they used unladen swallows to lift it?

...an African or a European Swallow?
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: llanitedave on 12/28/2015 05:25 am
Speaking of flyback --


once the stage is set up to use chilled fuel and subcooled oxidizer, could it do a flyback with the normal-temperature liquids, or would chilling equipment have to be available on the barge, or wherever?
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: guckyfan on 12/28/2015 06:04 am
Speaking of flyback --


once the stage is set up to use chilled fuel and subcooled oxidizer, could it do a flyback with the normal-temperature liquids, or would chilling equipment have to be available on the barge, or wherever?

I have been thinking of that, too. But I thought about the second stage. After a coast phase the LOX would no longer be subcooled, I expect. So the Merlin-vac will have to use LOX at near boiling point.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: John Alan on 12/28/2015 06:37 am
Speaking of flyback --


once the stage is set up to use chilled fuel and subcooled oxidizer, could it do a flyback with the normal-temperature liquids, or would chilling equipment have to be available on the barge, or wherever?

I have been thinking of that, too. But I thought about the second stage. After a coast phase the LOX would no longer be subcooled, I expect. So the Merlin-vac will have to use LOX at near boiling point.

IMHO... ;)
There may be max throttle % values based on RP1/LOX temps...
Subcooled can run at 100% thrust... if warmer fluids... some less value is ok...
I think the cooled RP1 is a bigger factor in letting the engine run higher thrust levels then we know...
I'm thinking this was likely researched and limits explored in Texas on the engine test stands...
Title: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Lars-J on 12/28/2015 06:49 am
Speaking of flyback --


once the stage is set up to use chilled fuel and subcooled oxidizer, could it do a flyback with the normal-temperature liquids, or would chilling equipment have to be available on the barge, or wherever?

I have been thinking of that, too. But I thought about the second stage. After a coast phase the LOX would no longer be subcooled, I expect. So the Merlin-vac will have to use LOX at near boiling point.

IMHO... ;)
There may be max throttle % values based on RP1/LOX temps...
Subcooled can run at 100% thrust... if warmer fluids... some less value is ok...
I think the cooled RP1 is a bigger factor in letting the engine run higher thrust levels then we know...
I'm thinking this was likely researched and limits explored in Texas on the engine test stands...

I doubt it. I think the subcooling is just to get more propellant in the same volume. Once it reaches the engine, it has already warmed up a bit, so the difference will be close to moot. M1D being qualified for higher thrust is likely not linked to subcooling, it just happened to be an upgrade that was available and made sense with more propellant.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Dante80 on 12/28/2015 06:56 am
Yes. Sub-cooling the propellant is done so that you carry more of it, not to get more performance.

Actually, you would need to heat the RP-1 (before loading it on the stage) instead of cooling it to enable better stage performance (per unit of propellant mass).
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: dgates on 12/28/2015 12:33 pm
Ok, I give!  Thanks! :).

But.... If one pulled a few engines.......

Turns out, not really workable.  Removing all nine engines would reduce the lift by roughly 10,000 lbs.  if we start with 50,000 lbs it still does not get into aerial lift weight ranges, or if it did it, would be right at the upper range.  I was thinking of a landed stage move that might be a few miles, say from an offshore island or a barge when the barge was needed for another landing quickly.

However, at 25 tons, a landed stage is a comparatively easy crane lift.  A crawler crane was used because of the good stability offered when doing a "lift then move" operation. 
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: CardBoardBoxProcessor on 12/28/2015 12:52 pm
DO we think eventually they will make a crane or vehicle or machine for this operation or continue to use a crane?
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: dgates on 12/28/2015 01:28 pm
DO we think eventually they will make a crane or vehicle or machine for this operation or continue to use a crane?

A on site transport erector (TE) might make sense at a high reuse / landing rate.  In any case a crane lift would be needed *somewhere*, as stages accumulate after successful landings.  I would not think SpaceX would wish to store landed stages on the TE. At current launch rates though, the practical "crane, translate to horizontal, truck over to wherever needed" works ok, seeing as how they got it done and done in less than 72 hours.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: edkyle99 on 12/28/2015 01:49 pm
DO we think eventually they will make a crane or vehicle or machine for this operation or continue to use a crane?
This question illustrates the still to be developed infrastructure that will be needed to handle returned stages if re-usability pans out.  A foremost need will be a hangar for storing/refurbishing/checking out returned stages.  Ground handling equipment will obviously be needed.  The crane setup at LZ-1 looks like an R&D arrangement rather than a long-term operational system.  If they use the barges, a completely different set of equipment will be needed.  And so on.

 - Ed Kyle
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: ugordan on 12/28/2015 01:54 pm
Crawling before walking, etc. This is only the first ever returned stage and I'd bet SpaceX can already see where the booster itself can/should be improved, let alone handling procedures/infrastructure. We're barely in the is cost-efficient reuse actually possible? phase now.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Nomadd on 12/28/2015 02:38 pm
Ok, I give!  Thanks! :).

But.... If one pulled a few engines.......

Turns out, not really workable.  Removing all nine engines would reduce the lift by roughly 10,000 lbs.  if we start with 50,000 lbs it still does not get into aerial lift weight ranges, or if it did it, would be right at the upper range.  I was thinking of a landed stage move that might be a few miles, say from an offshore island or a barge when the barge was needed for another landing quickly.

However, at 25 tons, a landed stage is a comparatively easy crane lift.  A crawler crane was used because of the good stability offered when doing a "lift then move" operation. 
An MI-26 can lift 44,000 pounds.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: cscott on 12/28/2015 03:05 pm
Normally you couldn't used 2 helos. The F9 core is so long that you can have a helo lifted from each end. But while possible, doesn't seem very practical or cheap.

The Russians tried it!
http://www.buran-energia.com/documentation/documentation-akc-air-transportation.php
Quote
The newly developed MI-26 helicopter of the weight-lifting capacity of 26 tons was offered for delivery by helicopter. According to this project, bulky cargoes of high mass (airframe and rocket bays) tied with cables had to be carried by 2 or 3 helicopters, and such ‘bundle’ had to move along the route, at the best fit height and flying speed. As the basis for such version the example of helicopters application for ‘crane’ operations was brought, but there was still no experience of flights ‘in bundles’.

Test flights with mock-up cargo having the configuration of a tank section of the rocket were carried out at LII. The tests revealed a complexity and risk of such kind of delivery. During one of the flights at a suddenly arisen weak turbulence of atmosphere, a ‘pendulous’ swing of cargo on the cables started which caused a disturbance of the helicopters flight stability, owing to what the crews were compelled to dump the cargo.

EDIT: to be clear (if you didn't read TFA) the Russians tried it and after trying to make it work *dismissed it as impractical*.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Lars-J on 12/28/2015 04:48 pm
Lifting the stage with a helicopter is a terrible idea, why keep bringing it up?
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Dante80 on 12/28/2015 04:57 pm
It's not a terrible idea at all, it would actually speed rapid re-usability considerably for barge landings.

It's simply impossible to do, since the helicopter to do the job doesn't exist. Thus, the whole discussion is a priori moot.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: RoboGoofers on 12/28/2015 05:25 pm
It's not a terrible idea at all, it would actually speed rapid re-usability considerably for barge landings.

It's simply impossible to do, since the helicopter to do the job doesn't exist. Thus, the whole discussion is a priori moot.

then use rigid airships!  ;)
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: uhuznaa on 12/28/2015 05:57 pm
I think streamlining all of this (post-landing processing as well as inspection/refurbishment) is low-hanging fruit when it comes to saving money by reusing stages. It's good old engineering and coming up with ideas that fit the problem, but not really rocket science. You certainly want to be able to retrieve and prepare for processing a landed stage as quickly, reliably and with as few workers as possible.

But there's no need to start doing this in any sophisticated way for the first landings.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: deltaV on 12/28/2015 06:50 pm
It's not a terrible idea at all, it would actually speed rapid re-usability considerably for barge landings.

It's simply impossible to do, since the helicopter to do the job doesn't exist. Thus, the whole discussion is a priori moot.

The largest helicopter ever built lifted 44 tonnes (https://en.wikipedia.org/wiki/Mil_V-12), which strongly suggests that it's possible to airlift a Falcon 9 first stage with an appropriately designed helicopter. It's just way too expensive to design, build and maintain a new one-of-a-kind near-record-breaking helicopter to be worth it.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: intrepidpursuit on 12/28/2015 06:53 pm
Why? Why would we use a helicopter to lift a rocket stage? A crane works just fine for now and Elon has already said that in the near future it will fly itself back from remote landing sites and land with "helicopter like precision".

Can we just drop this? They used a crane and a truck to transport the stage to 39A (you know, the topic of this thread) and NOT a helicopter.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: JamesG123 on 12/28/2015 07:07 pm
(http://www.movetransport.com/watertransport/images/Port_Canaveral.jpg)
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: macpacheco on 12/28/2015 07:11 pm
Much cheaper to just build an even bigger ASDS (the same size as LC1). Even if it takes a week to return to port.
An ASDS big enough to land a BFR first stage.

The concept of gas n' go was mostly a marketing ploy long term goal. Until 100% Raptor rockets that is. But with RTLS, a relaunch within 10 days might be very doable. The bottleneck will be having enough payloads to sustain that cycle.

Even if both stages could be reused, just build a big enough fleet to handle the transit and processing time.
Must have enough redundancy in case a booster suffers an accident (in flight or ground).
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Robotbeat on 12/28/2015 07:45 pm
Yes. Sub-cooling the propellant is done so that you carry more of it, not to get more performance.
Not true. Turbopumps can pump more of the subcooled propellant than they can of the non-subcooled propellant for the same power.

Also, I object to you defining performance as (basically) Isp. Mass fraction (which includes not just the tank mass for a certain amount of propellant but also the engine T/W ratio) is SUPER important, and often overlooked. It's /especially/ important for a boost-back VTVL first stage (and also super important for a SSTO rocket).

Propellant chilling isn't just a fancy way to avoid using longer tanks.

To illustrate:

Suppose you have a rocket with the first stage being 80% of the lift-off mass (500tons). It's built without much care for mass fraction, but still aerospace-grade mass fraction, and so has a mass of, say, 400t and a dry mass of 40 tons for a mass fraction of 10, and for the rocket equation, you have:

Exp(delta-v/Vexhaust)= 500/140 = 3.57

If you improved the mass fraction to, say, 35.7 (very difficult, but certainly possible with densification and advanced materials and manufacturing), you could keep 28.8 tons of propellant in that first stage for use for boost-back and landing, without affecting the performance of the primary stage. Your boost-back and landing available delta-v would be the same as the stage's imparted delta-v!

This is why mass fraction is actually more important for reusability than expendability: It reduces the total mass  that needs to be pushed around for the first stage after MECO. With expendability, the effect isn't as big because you're still pushing around the upper stage and the payload.


Or to help your intuition about why mass fraction is just so important for reusability (vs expendability):
...With an expendable rocket for a given payload, even an infinitesimally massive tank and rocket engine wouldn't be THAT big of a deal, you're still fighting the rocket equation on the way up. For a reusable rocket, it'd be an absolute godsend since the reuse penalty would be effectively zero (i.e. even the upper stage could just deorbit itself without consuming a significant amount of the payload).


...and the good news is that we can make HUGE strides in mass fraction, even though we've basically maxed out the exhaust velocity of chemical rockets. There are structural materials (Zylon, T1100G) with a strength-to-weight-ratio 20 times that of typical aerospace aluminum. And this is not an upper bound, we're making progress in improving strength continually (as well as improving manufacturing techniques to allow us to get the full benefit of our existing supermaterials). They have manufacturability constraints, but that's not enough to fully eliminate their utility, and this too can be improved.


Whenever anyone is introduced to rocketry, one of the first things they learn is the tyranny of the exponential rocket equation. What tends to be glossed over is the fact that it's actually easier to improve the mass fraction portion than the exhaust velocity portion.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: uhuznaa on 12/28/2015 07:51 pm
Why? Why would we use a helicopter to lift a rocket stage? A crane works just fine for now and Elon has already said that in the near future it will fly itself back from remote landing sites and land with "helicopter like precision".

Can we just drop this? They used a crane and a truck to transport the stage to 39A (you know, the topic of this thread) and NOT a helicopter.

It also would be quite pointless because then you'd have to land the stage with the helicopter somewhere and then you'd STILL need to get it down and onto wheels to move it around.

What I could imagine is a kind of universal cradle that you build a dozen of and then use to attach it to stages as soon as possible with some specialized equipment and then load this cradle with the stage onto trucks or cranes or whatever you need. Just something that takes bending loads and offers an assortment of rugged attachment points (including one over the CoG) to handle the stage whenever it needs to be moved or stored by whatever means.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Dante80 on 12/28/2015 08:12 pm
Yes. Sub-cooling the propellant is done so that you carry more of it, not to get more performance.
Not true. Turbopumps can pump more of the subcooled propellant than they can of the non-subcooled propellant for the same power.

Also, I object to you defining performance as (basically) Isp. Mass fraction (which includes not just the tank mass for a certain amount of propellant but also the engine T/W ratio) is SUPER important, and often overlooked. It's /especially/ important for a boost-back VTVL first stage (and also super important for a SSTO rocket).

Propellant chilling isn't just a fancy way to avoid using longer tanks.

To illustrate:

Suppose you have a rocket with the first stage being 80% of the lift-off mass (500tons). It's built without much care for mass fraction, but still aerospace-grade mass fraction, and so has a mass of, say, 400t and a dry mass of 40 tons for a mass fraction of 10, and for the rocket equation, you have:

Exp(delta-v/Vexhaust)= 500/140 = 3.57

If you improved the mass fraction to, say, 35.7 (very difficult, but certainly possible with densification and advanced materials and manufacturing), you could keep 28.8 tons of propellant in that first stage for use for boost-back and landing, without affecting the performance of the primary stage. Your boost-back and landing available delta-v would be the same as the stage's imparted delta-v!

This is why mass fraction is actually more important for reusability than expendability: It reduces the total mass  that needs to be pushed around for the first stage after MECO. With expendability, the effect isn't as big because you're still pushing around the upper stage and the payload.


Or to help your intuition about why mass fraction is just so important for reusability (vs expendability):
...With an expendable rocket for a given payload, even an infinitesimally massive tank and rocket engine wouldn't be THAT big of a deal, you're still fighting the rocket equation on the way up. For a reusable rocket, it'd be an absolute godsend since the reuse penalty would be effectively zero (i.e. even the upper stage could just deorbit itself without consuming a significant amount of the payload).


...and the good news is that we can make HUGE strides in mass fraction, even though we've basically maxed out the exhaust velocity of chemical rockets. There are structural materials (Zylon, T1100G) with a strength-to-weight-ratio 20 times that of typical aerospace aluminum. And this is not an upper bound, we're making progress in improving strength continually (as well as improving manufacturing techniques to allow us to get the full benefit of our existing supermaterials). They have manufacturability constraints, but that's not enough to fully eliminate their utility, and this too can be improved.


Whenever anyone is introduced to rocketry, one of the first things they learn is the tyranny of the exponential rocket equation. What tends to be glossed over is the fact that it's actually easier to improve the mass fraction portion than the exhaust velocity portion.

Thanks for the detailed answer. From what I understand, heating the propellant introduces more energy to the system per unit of propellant mass. I tried to make that clear in the post I made. That was the reason (for example), that kerosene in DeltaII was heated before loading into the rocket just prior to launch.

From what we know publicly, one of the main reasons that SpaceX decided to go for propellant densification was the fact that the F9 first stage was already approaching a limit where a further increase in height was considered counter-productive. Coupled with the fact that SpaceX wanted to keep the diameter the same for transportation reasons, led to the assertion that the way to bring more propellant to the rocket without changing the external dimensions was to...make it denser. 

Your input on mass fraction is welcome.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Comga on 12/28/2015 08:22 pm
Why? Why would we use a helicopter to lift a rocket stage? A crane works just fine for now and Elon has already said that in the near future it will fly itself back from remote landing sites and land with "helicopter like precision".

Can we just drop this? They used a crane and a truck to transport the stage to 39A (you know, the topic of this thread) and NOT a helicopter.

Please?
Can we put these "advanced" concepts in some discussion specifically for people who think they can out-engineer Musk?
Can we keep this one on the OG2 first stage?
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: John Alan on 12/28/2015 10:04 pm
Yes. Sub-cooling the propellant is done so that you carry more of it, not to get more performance.
Not true. Turbopumps can pump more of the subcooled propellant than they can of the non-subcooled propellant for the same power.

Also, I object to you defining performance as (basically) Isp. Mass fraction (which includes not just the tank mass for a certain amount of propellant but also the engine T/W ratio) is SUPER important, and often overlooked. It's /especially/ important for a boost-back VTVL first stage (and also super important for a SSTO rocket).

Propellant chilling isn't just a fancy way to avoid using longer tanks.

To illustrate:

Suppose you have a rocket with the first stage being 80% of the lift-off mass (500tons). It's built without much care for mass fraction, but still aerospace-grade mass fraction, and so has a mass of, say, 400t and a dry mass of 40 tons for a mass fraction of 10, and for the rocket equation, you have:

Exp(delta-v/Vexhaust)= 500/140 = 3.57

If you improved the mass fraction to, say, 35.7 (very difficult, but certainly possible with densification and advanced materials and manufacturing), you could keep 28.8 tons of propellant in that first stage for use for boost-back and landing, without affecting the performance of the primary stage. Your boost-back and landing available delta-v would be the same as the stage's imparted delta-v!

This is why mass fraction is actually more important for reusability than expendability: It reduces the total mass  that needs to be pushed around for the first stage after MECO. With expendability, the effect isn't as big because you're still pushing around the upper stage and the payload.


Or to help your intuition about why mass fraction is just so important for reusability (vs expendability):
...With an expendable rocket for a given payload, even an infinitesimally massive tank and rocket engine wouldn't be THAT big of a deal, you're still fighting the rocket equation on the way up. For a reusable rocket, it'd be an absolute godsend since the reuse penalty would be effectively zero (i.e. even the upper stage could just deorbit itself without consuming a significant amount of the payload).


...and the good news is that we can make HUGE strides in mass fraction, even though we've basically maxed out the exhaust velocity of chemical rockets. There are structural materials (Zylon, T1100G) with a strength-to-weight-ratio 20 times that of typical aerospace aluminum. And this is not an upper bound, we're making progress in improving strength continually (as well as improving manufacturing techniques to allow us to get the full benefit of our existing supermaterials). They have manufacturability constraints, but that's not enough to fully eliminate their utility, and this too can be improved.


Whenever anyone is introduced to rocketry, one of the first things they learn is the tyranny of the exponential rocket equation. What tends to be glossed over is the fact that it's actually easier to improve the mass fraction portion than the exhaust velocity portion.

Thanks for the detailed answer. From what I understand, heating the propellant introduces more energy to the system per unit of propellant mass. I tried to make that clear in the post I made. That was the reason (for example), that kerosene in DeltaII was heated before loading into the rocket just prior to launch.

From what we know publicly, one of the main reasons that SpaceX decided to go for propellant densification was the fact that the F9 first stage was already approaching a limit where a further increase in height was considered counter-productive. Coupled with the fact that SpaceX wanted to keep the diameter the same for transportation reasons, led to the assertion that the way to bring more propellant to the rocket without changing the external dimensions was to...make it denser. 

Your input on mass fraction is welcome.

And my point was the M1D is kept from melting using RP1 as a throat and chamber wall coolant...

The question was... what happens if the RP1/LOX is not subcooled...
(as in say a partial fill and sub orbital re-positioning hop)
Or as also mentioned a long S2 coast event...

I was implying that if you attempt to run thrust up to the new 100% with warm fluids...
It may RUD...  :o
Or it may suffer damage enough to not be reusable...  :-\
But... It may still run fine up to the old 85% thrust limit...
SpaceX knows if all this is either true or false...  :-X
My opinion is it may be true...  ;)

I get the mass fraction stuff... always did...  ;)
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: fast on 12/29/2015 12:04 pm
Yes. Sub-cooling the propellant is done so that you carry more of it, not to get more performance.
Not true. Turbopumps can pump more of the subcooled propellant than they can of the non-subcooled propellant for the same power.

Also, I object to you defining performance as (basically) Isp. Mass fraction (which includes not just the tank mass for a certain amount of propellant but also the engine T/W ratio) is SUPER important, and often overlooked. It's /especially/ important for a boost-back VTVL first stage (and also super important for a SSTO rocket).

Propellant chilling isn't just a fancy way to avoid using longer tanks.

To illustrate:

Suppose you have a rocket with the first stage being 80% of the lift-off mass (500tons). It's built without much care for mass fraction, but still aerospace-grade mass fraction, and so has a mass of, say, 400t and a dry mass of 40 tons for a mass fraction of 10, and for the rocket equation, you have:

Exp(delta-v/Vexhaust)= 500/140 = 3.57

If you improved the mass fraction to, say, 35.7 (very difficult, but certainly possible with densification and advanced materials and manufacturing), you could keep 28.8 tons of propellant in that first stage for use for boost-back and landing, without affecting the performance of the primary stage. Your boost-back and landing available delta-v would be the same as the stage's imparted delta-v!

This is why mass fraction is actually more important for reusability than expendability: It reduces the total mass  that needs to be pushed around for the first stage after MECO. With expendability, the effect isn't as big because you're still pushing around the upper stage and the payload.


Or to help your intuition about why mass fraction is just so important for reusability (vs expendability):
...With an expendable rocket for a given payload, even an infinitesimally massive tank and rocket engine wouldn't be THAT big of a deal, you're still fighting the rocket equation on the way up. For a reusable rocket, it'd be an absolute godsend since the reuse penalty would be effectively zero (i.e. even the upper stage could just deorbit itself without consuming a significant amount of the payload).


...and the good news is that we can make HUGE strides in mass fraction, even though we've basically maxed out the exhaust velocity of chemical rockets. There are structural materials (Zylon, T1100G) with a strength-to-weight-ratio 20 times that of typical aerospace aluminum. And this is not an upper bound, we're making progress in improving strength continually (as well as improving manufacturing techniques to allow us to get the full benefit of our existing supermaterials). They have manufacturability constraints, but that's not enough to fully eliminate their utility, and this too can be improved.


Whenever anyone is introduced to rocketry, one of the first things they learn is the tyranny of the exponential rocket equation. What tends to be glossed over is the fact that it's actually easier to improve the mass fraction portion than the exhaust velocity portion.

Thanks for the detailed answer. From what I understand, heating the propellant introduces more energy to the system per unit of propellant mass. I tried to make that clear in the post I made. That was the reason (for example), that kerosene in DeltaII was heated before loading into the rocket just prior to launch.

From what we know publicly, one of the main reasons that SpaceX decided to go for propellant densification was the fact that the F9 first stage was already approaching a limit where a further increase in height was considered counter-productive. Coupled with the fact that SpaceX wanted to keep the diameter the same for transportation reasons, led to the assertion that the way to bring more propellant to the rocket without changing the external dimensions was to...make it denser. 

Your input on mass fraction is welcome.

And my point was the M1D is kept from melting using RP1 as a throat and chamber wall coolant...

The question was... what happens if the RP1/LOX is not subcooled...
(as in say a partial fill and sub orbital re-positioning hop)
Or as also mentioned a long S2 coast event...

I was implying that if you attempt to run thrust up to the new 100% with warm fluids...
It may RUD...  :o
Or it may suffer damage enough to not be reusable...  :-\
But... It may still run fine up to the old 85% thrust limit...
SpaceX knows if all this is either true or false...  :-X
My opinion is it may be true...  ;)

I get the mass fraction stuff... always did...  ;)

RP-1 and LOX inside first stage getting warmer all the time before and during launch, and especially during reentry burn when stage with little amount of LOX and RP-1 flying through its exhaust plume.
So if the question is if M1D is able to work normally on not sub cooled PR-1 and LOX, it is reasonable to assume it can.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: the_other_Doug on 12/29/2015 04:30 pm
And, really, how much less efficient is it to cool a thousands-of-degrees-hot combustion chamber with 70-degree-F RP1 than with 20-degree-F RP1?  Think of the difference in temperatures between the chamber and the coolant -- the change in that difference caused by warm vs. deep-cooled RP1 would seem insignificant.

I mean, let's say the chamber runs at about 3,000 degrees F.  (I'm pulling that number out of the air, but it doesn't seem unreasonable, and is for illustration purposes only.)  Deep-cooled RP1 at 20 degrees F would be 2,980 degrees cooler than the chamber as it enters the cooling tubes around the chamber.  Warm 70-degree-F RP1 would be 2,930 degrees cooler than the chamber.

Are we really worried that this difference would make a significant change to the RP1's capability to keep the combustion chamber from melting?

Really?
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: science_business on 12/29/2015 04:38 pm
Please move these posts to appropriate thread.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: servicepack1 on 01/01/2016 04:15 am
Not sure if anyone has seen Elon's instagram pic or not.

https://www.instagram.com/p/_-d28bQEc9/ (https://www.instagram.com/p/_-d28bQEc9/)
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: dcporter on 01/01/2016 04:31 am
Not sure if anyone has seen Elon's instagram pic or not.

https://www.instagram.com/p/_-d28bQEc9/ (https://www.instagram.com/p/_-d28bQEc9/)

Numerous people on numerous threads, but this one seems like a sensible cross-post. 👍🏻
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: slaven0 on 01/04/2016 03:22 pm
just seen this comment on ArsTechnica (http://arstechnica.com/science/2016/01/new-photos-of-spacex-booster-show-sooty-but-undamaged-rocket/?comments=1).
Where to put returned stage?

Quote
If I was Musk,

I'd place it down somewhere near HQ, build a bar around it and call it "THE Club"

 ;D
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: tleski on 01/04/2016 03:27 pm
just seen this comment on ArsTechnica  (http://"http://arstechnica.com/science/2016/01/new-photos-of-spacex-booster-show-sooty-but-undamaged-rocket/?comments=1").
Where to put returned stage?

Quote
If I was Musk,

I'd place it down somewhere near HQ, build a bar around it and call it "THE Club"

 ;D

Your link doesn't work.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Swoopert on 01/04/2016 03:39 pm
just seen this comment on ArsTechnica (http://arstechnica.com/science/2016/01/new-photos-of-spacex-booster-show-sooty-but-undamaged-rocket/?comments=1).
Where to put returned stage?

Quote
If I was Musk,

I'd place it down somewhere near HQ, build a bar around it and call it "THE Club"

 ;D

Your link doesn't work.

Fixed...ArsTechnica (http://arstechnica.com/science/2016/01/new-photos-of-spacex-booster-show-sooty-but-undamaged-rocket/?comments=1).
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: oldAtlas_Eguy on 01/04/2016 06:00 pm
A general comment about post landing processing.

It took them only 3 days to safe the vehicle, install lift rings, lift the stage and remove the legs, place it on a transporter and then get to and inside LC39A. Only using existing normal transport equipment and general purpose cranes. It was also the first time they ever did this.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Dante80 on 01/04/2016 06:39 pm
Some more are out.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: woods170 on 01/04/2016 06:49 pm
Some more are out.
Heh. The Falcon logo on the other side fared better than the one from Elon's previous tweet.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: CorvusCorax on 01/06/2016 12:12 am
Attached image with closeups of the interstage image from flickr.

That looks to me like at least the interstage would need more than just a bit of cleaning to refly.

The paint-job is definitely a goner. The paint is blistered all over and in places has peeled away down to the foundation or even completely. Might as well sand blast it away altogether.

Also these screw-heads stand out a bit too far for my liking (I can't really imagine the stage launching like this) and those cracks in the paint layer around them suggest quite significant bending has occurred. If the interstage is carbon-fibre-alomunium honeycomb like the fairing, this doesn't bode well for its structure.
Also are those actual cracks around the screw-heads themselves?

If so, then the interstage like this would never fly a second time. It would be cheaper to throw it and maybe keep the grid fins and internal modules for parts than to repair that kind of damage.

Of course this particular rocket isn't gonna fly anyway and for a static fire the interstage can likely stay. But for actual re-use they'd have to look into that.

Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: starhawk92 on 08/03/2016 05:20 pm
Is it possible to rename this thread in line with the other S1 core tracking thread?

"Hysterical Porpoises" thanks you in advance!
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: dodo on 08/26/2016 09:50 am
*bump*

First stage in exhibition:

https://twitter.com/ShuttleCDRKelly/status/768609419168997377

https://twitter.com/astro_g_dogg/status/768983913318404096
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: DAZ on 08/26/2016 09:56 pm
If they had to repaint the interstage than they should have repainted it plaid. ;D
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: CyndyC on 08/27/2016 09:02 pm
*bump*

First stage in exhibition:

https://twitter.com/ShuttleCDRKelly/status/768609419168997377

https://twitter.com/astro_g_dogg/status/768983913318404096

Nice touch that they reopened the grid fins, like a freeze frame of precisely when the stage landed, not after it came to rest and the fins were closed.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: rpapo on 08/27/2016 09:23 pm
Nice touch that they reopened the grid fins, like a freeze frame of precisely when the stage landed, not after it came to rest and the fins were closed.
But it's clean!
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: JebK on 08/27/2016 09:32 pm
Nice touch that they reopened the grid fins, like a freeze frame of precisely when the stage landed, not after it came to rest and the fins were closed.
But it's clean!

And not on fire.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: CyndyC on 08/27/2016 11:31 pm
Nice touch that they reopened the grid fins, like a freeze frame of precisely when the stage landed, not after it came to rest and the fins were closed.
But it's clean!

And not on fire.

Now that you bring that up, an eternal flame underneath might be another nice touch. Wikip says eternal flames are found all over the world, but in the long list they appear to commemorate only victims of war & violence, whereas at SpaceX one could symbolize new beginnings, a much more appealing sentiment. Sorry the same can't be said for putting soot back on the stage though, rpapo :).
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: rpapo on 08/28/2016 10:34 am
Sorry the same can't be said for putting soot back on the stage though, rpapo :).
What little I said could be taken many ways, and I was actually referring to the grid fins looking downright plastic in their clean-ness.  There's new clean, there's used clean, and there's substitution.  I doubt those grid fins are the real thing: they're too white and look lighter (more flimsy) than the real units.  The real units were possibly removed for reuse, as some have speculated here.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Kabloona on 08/28/2016 01:17 pm
Sorry the same can't be said for putting soot back on the stage though, rpapo :).
What little I said could be taken many ways, and I was actually referring to the grid fins looking downright plastic in their clean-ness.  There's new clean, there's used clean, and there's substitution.  I doubt those grid fins are the real thing: they're too white and look lighter (more flimsy) than the real units.  The real units were possibly removed for reuse, as some have speculated here.

Here's a closeup. It looks like they're just new (metal) fins without the SPAM coating, only painted, with new anti-pigeon technology.  ;)  Second photo for comparison from a different returned stage.

First photo credit: Gene Blevins/LA Daily News
Second photo credit: John Kraus

(BTW, John's website says he's a mere lad 16 years young, with some impressive space launch shots. Check it out: http://johnkrausphotos.com)
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: cuddihy on 08/28/2016 03:17 pm
I'd bet those are Aluminum vice Titanium as the flight ones are.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Lar on 08/28/2016 03:40 pm
Why add extra cost by using different materials or different fab techniques? I could see using a prototype SpaceX had already but I can't see SpaceX doing custom design work just for a display which is a one off.

These are either prototypes, rejects from the production line or just regular production line items.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: wannamoonbase on 08/28/2016 03:54 pm
I understand the appeal of having this stage back in Hawthorne.  However, being outside in the elements is disappointing.

I'd rather see it fly again or be in the Smithsonian than slowly decaying outside.

They could have used one of the abused GTO boosters as a lawn ornament.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: matthewkantar on 08/28/2016 08:29 pm
I believe all of the grid fins to date are aluminum. If someone has a good citation showing them to be of titanium, I'd like to see it.

Matthew
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: guckyfan on 08/28/2016 08:38 pm

They could have used one of the abused GTO boosters as a lawn ornament.

This is the first, no replacement for it.

Edit: They are all capable of reflight.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Kabloona on 08/28/2016 09:25 pm
I believe all of the grid fins to date are aluminum. If someone has a good citation showing them to be of titanium, I'd like to see it.

Matthew

Yes, I doubt we would have seen the occasional (assumed) melting of grid fin cell walls with titanium.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: yokem55 on 08/29/2016 03:27 am
I understand the appeal of having this stage back in Hawthorne.  However, being outside in the elements is disappointing.

I'd rather see it fly again or be in the Smithsonian than slowly decaying outside.

They could have used one of the abused GTO boosters as a lawn ornament.
The elements in Hawthorne are relatively benign. The climate is generally hot and dry most of the time (less than 13"/year of precip). Air pollution might eventually cause issues, but rust probably won't the one of them in the near term.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: CuddlyRocket on 08/29/2016 04:15 am
I understand the appeal of having this stage back in Hawthorne.  However, being outside in the elements is disappointing.

I'd rather see it fly again or be in the Smithsonian than slowly decaying outside.

I'm sure the Smithsonian and plenty of others would agree with you. However, presumably SpaceX thinks there's some advantage to them of having it where it is. It certainly makes a statement!
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Coastal Ron on 08/29/2016 04:25 am
I understand the appeal of having this stage back in Hawthorne.  However, being outside in the elements is disappointing.

I'd rather see it fly again or be in the Smithsonian than slowly decaying outside.

They could have used one of the abused GTO boosters as a lawn ornament.
The elements in Hawthorne are relatively benign. The climate is generally hot and dry most of the time (less than 13"/year of precip). Air pollution might eventually cause issues, but rust probably won't the one of them in the near term.

There are lots of rocket parts on display in outside conditions around southern California, some having been there for decades.  And since Hawthorne is 7 miles from the Pacific ocean the air doesn't get too dry, but could be a little salty depending on the fog.

I'm sure SpaceX knows the conditions this museum piece will be in, and I wouldn't be surprised if this is just a temporary installation (i.e. years, not decades) until it moves to it's final resting point.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: david1971 on 08/29/2016 06:03 am
I understand the appeal of having this stage back in Hawthorne.  However, being outside in the elements is disappointing.

I'd rather see it fly again or be in the Smithsonian than slowly decaying outside.

They could have used one of the abused GTO boosters as a lawn ornament.
The elements in Hawthorne are relatively benign. The climate is generally hot and dry most of the time (less than 13"/year of precip). Air pollution might eventually cause issues, but rust probably won't the one of them in the near term.

There are lots of rocket parts on display in outside conditions around southern California, some having been there for decades.  And since Hawthorne is 7 miles from the Pacific ocean the air doesn't get too dry, but could be a little salty depending on the fog.

I'm sure SpaceX knows the conditions this museum piece will be in, and I wouldn't be surprised if this is just a temporary installation (i.e. years, not decades) until it moves to it's final resting point.

I visited Palmdale last year, and was pleasantly reminded that there's an SCA up there (spare parts for SOFIA, I think).  There were also a pair of SR-71s and a U2, amongst several other planes, just sitting out in the open.  Sure, I'd rather have all of these in nice climate-controlled environments, but they seem to be holding up OK in their current environment.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: woods170 on 08/29/2016 08:24 am
I understand the appeal of having this stage back in Hawthorne.  However, being outside in the elements is disappointing.

I'd rather see it fly again or be in the Smithsonian than slowly decaying outside.

They could have used one of the abused GTO boosters as a lawn ornament.
The elements in Hawthorne are relatively benign. The climate is generally hot and dry most of the time (less than 13"/year of precip). Air pollution might eventually cause issues, but rust probably won't the one of them in the near term.

There are lots of rocket parts on display in outside conditions around southern California, some having been there for decades.  And since Hawthorne is 7 miles from the Pacific ocean the air doesn't get too dry, but could be a little salty depending on the fog.

I'm sure SpaceX knows the conditions this museum piece will be in, and I wouldn't be surprised if this is just a temporary installation (i.e. years, not decades) until it moves to it's final resting point.
Minor nit. It's not a museum piece. It's a display piece. Small, but significant difference.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: Zed_Noir on 08/29/2016 10:50 am
I understand the appeal of having this stage back in Hawthorne.  However, being outside in the elements is disappointing.

I'd rather see it fly again or be in the Smithsonian than slowly decaying outside.

They could have used one of the abused GTO boosters as a lawn ornament.
The elements in Hawthorne are relatively benign. The climate is generally hot and dry most of the time (less than 13"/year of precip). Air pollution might eventually cause issues, but rust probably won't the one of them in the near term.
...
I'm sure SpaceX knows the conditions this museum piece will be in, and I wouldn't be surprised if this is just a temporary installation (i.e. years, not decades) until it moves to it's final resting point.

Think both the COT-1 Dragon ceiling mobile and the OG2 Falcon 9 booster stage totem pole will be pass on to the Smithsonian once there is something to take their places. Like the 1st crew Dragon capsule and the 1st reused Falcon 9 booster stage after several flights.

Also give the Smithsonian some time to figure out how to display a 15 storeys tall exhibit.
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: docmordrid on 08/29/2016 03:09 pm
Hmmmm...is there room there for the first retired BFS? Maybe have to take down another small building though....
Title: Re: Returned Falcon 9 OG2 First Stage Transported to 39A HIF
Post by: FutureSpaceTourist on 12/19/2016 08:09 pm
How's this for an early Xmas present:

Quote
So awesome to get a piece of the first orbital-class rocket that landed on earth!  (landed a year ago this week!)

https://twitter.com/spacextrip/status/810947104906428416 (https://twitter.com/spacextrip/status/810947104906428416)

Trip's twitter profile says he's the SpaceX manager of Falcon launch fleet operations.