SpaceX (general discussion)

The eventual goal is to gas the thing up *at* *sea* and launch it back to Canaveral, so the barge could remain at sea. I'd think, in that case, it might be better to replace the small barge with a larger one built atop something like a second-hand container ship. Larger, more stable; with the ability to take a whole lot of payload, it could be heavily armored so it could shrug off a direct hit from an errant rocket. Onboard RP storage.
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I think I'd want my propellant on a separate craft from the pad at sea. The pad just needs a stable deck space and a crane.

I'm also curious about the numbers that make keeping the pad at sea replenished with rocket fuel, refueling the rocket, and burning the fuel for a return flight cheaper than putting the rocket on ship and sailing it back to the cape. Especially since one could almost immediately out it on a ship for a return trip and do all your diagnostic stuffs and minor repair en route to the cape. And refuel on terra firma.
 
sferrin said:
https://youtu.be/TGXUW_n8-TM

That little slide there at the end could have been disastrous. I wonder if there's a way to improve "grip". On second thought maybe that slide reduces the chances of it tipping over.
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It didn't slide - it bounced. Important distinction, imho. Partly because from the legs, but mostly because of residual thrust. OG2 did the same.
 
flanker said:
sferrin said:
https://youtu.be/TGXUW_n8-TM

That little slide there at the end could have been disastrous. I wonder if there's a way to improve "grip". On second thought maybe that slide reduces the chances of it tipping over.
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It didn't slide - it bounced. Important distinction, imho. Partly because from the legs, but mostly because of residual thrust. OG2 did the same.
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I know it bounced. They landed a giant spring. "Laterial translation after initial touchdown" then if you like that better. The net result is the same.

HD version of the landing. (Can't wait until they do a Heavy. A pair coming back to the Cape and one at sea would be quite a show.)

https://www.youtube.com/watch?v=3QeG8mc21VE
 
sferrin said:
Moose said:
Heh, there's a lot more hurdles to anyone buying Big E than just a pricetag. But it will certainly be interesting to see what direction the drone ships evolve in.
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Those big container ships are relatively inexpensive. Maybe they could customize one of those. Or do like Sea Launch with the advantage that they could land near the ship (I don't think you'd want to land ON the ship just in case there was a problem).
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Borrowing the idea of using a mobile rig from SeaLaunch is what I expect; especially if the idea is to land cores at sea, refuel them, and fly them back to land a more stable/commodious but less mobile rig would be the logical approach. SeaLand?
 
sferrin said:
Moose said:
Heh, there's a lot more hurdles to anyone buying Big E than just a pricetag. But it will certainly be interesting to see what direction the drone ships evolve in.
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Those big container ships are relatively inexpensive. Maybe they could customize one of those. Or do like Sea Launch with the advantage that they could land near the ship (I don't think you'd want to land ON the ship just in case there was a problem).
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The new ones aren't cheap...
There has been a competition the last 10 years to bring down costs per container by upping size and efficiency.
But that pushes up the price by boat way up.
Furthermore, container ships are not that roll free, they need speed to limit it, the ballasting is limited, so is available power etc...
Not forgetting that they are just a massive floating hollowed out log: no "deck" that could carry much of anything.

However,
If one was to use an older oil tanker in the 150/200m tange - then we are talking:
- Clean er' up to Marpol standards, coat the cargo tanks with antifouling.
- Site all O2 / Fuel tanks deep in the rear bottom of the unused clean/dirty slop tank
- remove deck piping, leaving only filling and emptying (no more transfers, recycling, heaters, gas pipes, steam pipes etc).
- Reinforce deck 80/100m away from superstructure at the front of vessel.
Ops
- Light ship to launch zone.
- Fill up cargo tanks with sea water heading 2/3knts into waves: more stable than a Swiss Bank.
- Erect Falcon/launch
Etc.

There is a lot power available that is normally used for loading/discharging, heating cargo and all that jazz.
This comes either in mechanical, steam or electric form, leaving lots of design options.
 
sferrin said:
https://youtu.be/TGXUW_n8-TM

That little slide there at the end could have been disastrous. I wonder if there's a way to improve "grip". On second thought maybe that slide reduces the chances of it tipping over.
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Thank you very much for the video - didn't heard of it before. Very nice.
 
http://motherboard.vice.com/en_uk/read/meet-the-truthers-who-believe-spacex-faked-its-rocket-landing

I didn't know this was a thing. Perhaps it's not surprising considering some 6% of Americans believe the moon landings were faked, and a whopping 25% of Brits do too
 
skyblue said:
http://motherboard.vice.com/en_uk/read/meet-the-truthers-who-believe-spacex-faked-its-rocket-landing

I didn't know this was a thing. Perhaps it's not surprising considering some 6% of Americans believe the moon landings were faked, and a whopping 25% of Brits do too
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Well I'd expect as much given today's youth.
 
Without wishing to stray too far OT, I'd take that "25%" with a massive pinch of salt. Never [personally] heard anyone express that opinion on this side of the Atlantic.
 
Answering here because we dont need more off topic in the BO thread.

Moose said:
I may not be recalling this exactly right, but i beleive the word over at NSF around the time that the chutes were dropped was that they figured the stages would still need a breaking burn in order to survive so why not just get rid of the chutes and concentrate on maturing the propulsive recovery idea.
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They were aware of that for a long time, before they got rid of parachutes. Here is Elon talking about doing propulsive landings back in very early 2009;

https://www.nasaspaceflight.com/2009/01/musk-ambition-spacex-aim-for-fully-reusable-falcon-9/

TomS said:
In a sense, they already do. SpaceX does static fire tests of its rockets a week or so before each launch.

Falcn 1 is no longer offered. Payloads in that size can piggyback on a Falcon 9 main payload.
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They do static full duration fire for every engine, then static full (almost) duration fire of a core, then they ship the core to launch site and do a WDR + short static fire. They do this for every core.
 
https://www.youtube.com/watch?v=mDoyWcLtBC4

https://www.youtube.com/watch?v=YCv31VFk1Lg
 
Am I seeing things or did the upper structure (between upper LOX tank bulkhead and base of second-stage) buckle? It looks like the radial seam at the base of this structure has bulged out and popped some rivets.

Those waffle stabilizers exert a lot of torque and sheer loads on that portion of the vehicle. What's up?

Naw! ... I got it wrong. Looking at the last part of the video showing the pre-launch arrangement I see that bulge -- it's an artifact of the design.

Never mind! Spoke too soon.

David
 
flanker said:
Answering here because we dont need more off topic in the BO thread.

Moose said:
I may not be recalling this exactly right, but i beleive the word over at NSF around the time that the chutes were dropped was that they figured the stages would still need a breaking burn in order to survive so why not just get rid of the chutes and concentrate on maturing the propulsive recovery idea.
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They were aware of that for a long time, before they got rid of parachutes. Here is Elon talking about doing propulsive landings back in very early 2009;

https://www.nasaspaceflight.com/2009/01/musk-ambition-spacex-aim-for-fully-reusable-falcon-9/

TomS said:
In a sense, they already do. SpaceX does static fire tests of its rockets a week or so before each launch.

Falcn 1 is no longer offered. Payloads in that size can piggyback on a Falcon 9 main payload.
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They do static full duration fire for every engine, then static full (almost) duration fire of a core, then they ship the core to launch site and do a WDR + short static fire. They do this for every core.
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Thanks for that...

cheers,
Robin.
 
fredymac said:
Another launch coming up. Hot fire scheduled for today. If schedules don't slip, earliest launch would be Thursday and another barge landing is planned. 2 more flights soon after with more barge landings likely. The landing will be tougher than last time due to the launch trajectory.


http://spaceflightnow.com/2016/04/29/commercial-falcon-9-rocket-launch-scheduled-for-next-week/
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Wow! that is a quick turn around from the last launch. Any idea that they will be using the same launcher as the last time?
 
FighterJock said:
fredymac said:
Another launch coming up. Hot fire scheduled for today. If schedules don't slip, earliest launch would be Thursday and another barge landing is planned. 2 more flights soon after with more barge landings likely. The landing will be tougher than last time due to the launch trajectory.


http://spaceflightnow.com/2016/04/29/commercial-falcon-9-rocket-launch-scheduled-for-next-week/
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Wow! that is a quick turn around from the last launch. Any idea that they will be using the same launcher as the last time?
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It isn't; I've forgotten the timeline, but each first stage takes a month or two to be inspected, tested and readied for launch. They intend to cut that down once they have trend data, etc, but either way they'll need to have a few rockets in rotation.
 
FighterJock said:
Wow! that is a quick turn around from the last launch. Any idea that they will be using the same launcher as the last time?
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Musk twitter that that landed stage will be reuse in june/july this year

This could be CRS-9 or Iridium NEXT flight 1
 
https://gcaptain.com/watch-incredible-360-degree-video-of-spacexs-historic-rocket-landing/
 
And they stick the landing! Looks almost dead center.

edit: Hmmmm. . . fire doesn't seem to want to go out. :eek:
 
It's starting to look routine. A couple more and it may start to become boring.
 
The significance of this time around is they re-entered with twice the velocity (2km/s; due to launching JCSAT-14 into a geostationary orbit) and experienced eight times the heating of their last attempt. This also represents a key milestone desired / required for launching Falcon Heavy later this year.
 

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Anybody know what was up with those flames that didn't want to go out? (Or that spray nozzle that couldn't seem to get the water aimed toward the rocket?)
 
fredymac said:
It's starting to look routine. A couple more and it may start to become boring.
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High speed reentry to a landing on a postage stamp out to sea in the middle of the night. I'll bet ULA doesn't think it's boring. ;)
 
sferrin said:
Anybody know what was up with those flames that didn't want to go out? (Or that spray nozzle that couldn't seem to get the water aimed toward the rocket?)
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Just excess leaking fuel; it's not uncommon and will put itself out soon enough.
 
I hope they're able to get the Heavy launched this year. If they managed to land all three cores that would blow some minds.

https://www.youtube.com/watch?v=4Ca6x4QbpoM
 
https://www.youtube.com/watch?v=b6Fkx7fAy_Q
 
According to Spacex Twitter this landing used 3 engines rather than just 1. I am impressed they make changes like this without the agonizing navel gazing Nasa goes through. They probably ran simulations and verified software functionality but no Grasshopper tests.
 
Due to the extreme thrust-to-weight ratio of those engines, you can't really do a Grasshopper-style test. The original Grasshopper is also scattered over Texas.
 
Yes, they used 3 engines rather than 1 with 6s burn vs the normal one engine 30s burn. Much more efficient this way. They did the same with SES-9, but then they punched a hole through the poor ASDS. :D Amazing they managed to nail this super difficult mission smoothly like that just on a second try. The fire isnt a worry, seen stuff like that before, even during OG2 launch attempt.

The Grasshopper is alive and well. The scattered frame is F9R Dev 1, which is not the grasshopper.
 
Landed the rocket again? At this rate, it is starting to look awfully routine...
 
DrRansom said:
Landed the rocket again? At this rate, it is starting to look awfully routine...
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For SpaceX anyway. Still waiting for ULA to bring back a rocket. ;D
 
Landing video without the flare washout. Calm seas so no skipping after touchdown this time (or at least too little to matter).

https://www.youtube.com/watch?v=LHqLz9ni0Bo
 
fredymac said:
Landing video without the flare washout. Calm seas so no skipping after touchdown this time (or at least too little to matter).

https://www.youtube.com/watch?v=LHqLz9ni0Bo
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It actually slides several feet. Go to 0:42, put your eye on the "pole" in the foreground, and then watch the vehicle slide several feet to the left. Maybe that's not a bad thing though (all things considered). The mass wants to move and if it couldn't slide maybe it would "trip" and tip over. Watching the nose there at 1:09 and on the vehicle is oscillating noticeably. Whether from residual vibration from the landing, wave motion from the water, or both, I don't know.
 
I missed that. It seems odd to have moved like that. I get the impression it is related to that spurt of thrust you see after the landing. I wonder if they vent/purge any leftover fuel that is already reaching the engines and with 3 engines they got more lift than anticipated.
 
fredymac said:
I missed that. It seems odd to have moved like that. I get the impression it is related to that spurt of thrust you see after the landing. I wonder if they vent/purge any leftover fuel that is already reaching the engines and with 3 engines they got more lift than anticipated.
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My W.A.G. is that there is still a combination of horizontal and vertical oscillation within the rocket itself briefly making it "light on it's feet". Combined with the movement of the barge (stabilization ain't perfect) and you get a bit of sliding.
 

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