11:20 UTC (6:20 AM Eastern). You can always find the latest launch dates w/ times here once they're published: Upcoming Launches | SpaceX Stats
-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
11:20 UTC (6:20 AM Eastern). You can always find the latest launch dates w/ times here once they're published: Upcoming Launches | SpaceX Stats
So that's what that was! Thanks, I didn't know.
But why do they have a camera inside that tank? Just because the images look cool? I doubt it. Is visually monitoring the liquid O2 important?
chickensevil
Active Member
The internal camera was added a few launches back. I think it helps them see how much excess fuel they left on the second stage. Just a guess? I don't recall why Ben said he added it. But it sure is cool
Also, technically is isn't a true zero g. You should look up how gravity affects the ISS since they aren't actually in zero g. It just seems that way. What is actually happening is that they are going around the earth so fast that it keeps them floating. You don't hit true zero g affects until you get farther away from the earth. Sorry its a semantics thing.
Free fall is free fall ('zero gravity' is not zero in the ISS orbit coz atmospheric drag -> not real free fall). Also gravity is infinite force, you can't escape it. It's only 'zero' between two gravity wells and that is, thanks to Einstein, exactly same as free fall...
Last edited:
The internal camera was added a few launches back. I think it helps them see how much excess fuel they left on the second stage. Just a guess? I don't recall why Ben said he added it. But it sure is cool
Shots of the inside view of the second stage tank (from the top looking down to the fuel extraction point at the base of the tank) are at:
25:18 - 25:26 (you can see the fuel stop draining from the tank and start to shift around at 25:22 at Stage Cut Off)
26:11 - 27:48
29:26 - 29:38
31:27 - 31:38
https://www.youtube.com/watch?v=p7x-SumbynI
I'm guessing they continued watching/recording the behaviour of the fuel inside the tank all the way down to stage breakup. I guess they need to understand how they can get the remaining fuel to the right part of the tank in order to restart the main engine which will be a key part of Second Stage recovery. (See 1:19 on https://www.youtube.com/watch?v=sSF81yjVbJE )
Stopping and restarting an engine is part of a GTO launch so I imagine that bit isn't a problem. But for GTO you don't have to flip the rocket over to get it to point the other way.
How did the Shuttle do it?
Last edited:
rolosrevenge
Dr. EVS
While I don't know exactly how Shuttle did it, there are essentially 2 ways to do it:
* use membranes (not so easy with cryogenic fuels, but used for Kerosine/peroxide, etc.) with pressurized volume on the other side. Notice that the membrane doesn't have to be elastic, just flexible.
* use the gravity/inertia to locate the fuel around the collection points.
The latter is used for most of the fuels/oxidizers. Positioning of the liquids in the low gravity can be done by either starting a small engine or by slowly extracting some amount of fuel/LOX into a small pressurized volume (electric-driven pump is enough) and starting the engine using this collected fuel. This stage is usually called "pressurizing" and we can hear pressurization reports/calls on some footages. Then the started engine pushes the rocket one way, the fuel moves the other way, and this is where the collector will take it from. This moment is critical, since the fuel tends to slosh around a lot when Gs change quickly. So, you'll see lots of buffles or other interesting geometry usually around collector ports.
How can the electric pumps collect fuel/LOX, one might ask? Surface tension. Over time (and it's pretty short period of time), when blobs of fuel/LOX stops flying around in zero Gs, they merge and/or hit the walls of the tank. Then they cover the walls in a pretty even layer of liquid. Notice that the fuel blobs are all over the place and the collector port is essentially dry at 26:11, but they're fewer of them and the collector port is covered with liquid at 31:27. That's surface tension. It allows the pumps to extract enough to start the engine and push the rest to the collection port.
chickensevil
Active Member
Given recent comments I don't know that they are going to focus on second stage recovery. The last I heard was that the cost savings on the second stage wasn't nearly as great as the first stage so it wouldn't necessarily be worth the effort and they would look to move on toward the bigger projects (like mars). Not to mention they would need a considerable amount of extra fuel to turn the second stage around push it back to earth and slow down against the gravity that it would seriously compromise the payload amount. It is possible, sure... But it might not be worth it. ROI on the R&D cost didn't seem to pan out I suppose.
That being said I'm sure they haven't totally ruled it out... But yeah... Not really expecting it.
That being said I'm sure they haven't totally ruled it out... But yeah... Not really expecting it.
It is easy to overlook everything that goes on with Dragon after it berths and before it returns. Interesting read
CRS-5: Dextre grabs CATS from the belly of a Dragon
"Canada’s multi-tasking robot, Dextre, successfully removed the CATS (Cloud-Aerosol Transport System) payload from the unpressurised trunk of the CRS-5/SpX-5 Dragon on Thursday morning. The payload was handed over to the Japanese Experiment Module, Kibo, marking the first “handover” between the Canadian robot and the JAXA arm."....
http://www.nasaspaceflight.com/2015/01/crs-5-dextre-grabs-cats-belly-dragon/
CRS-5: Dextre grabs CATS from the belly of a Dragon
"Canada’s multi-tasking robot, Dextre, successfully removed the CATS (Cloud-Aerosol Transport System) payload from the unpressurised trunk of the CRS-5/SpX-5 Dragon on Thursday morning. The payload was handed over to the Japanese Experiment Module, Kibo, marking the first “handover” between the Canadian robot and the JAXA arm."....
http://www.nasaspaceflight.com/2015/01/crs-5-dextre-grabs-cats-belly-dragon/
The Dragon capsule was recovered successfully. Another successful resupply run completed by SpaceX.
I'd like to point out how incredible this is for a company that had its first successful flight only six years ago. They are on the verge of landing a booster rocket and creating reusability. Unbelievable.
I'd like to point out how incredible this is for a company that had its first successful flight only six years ago. They are on the verge of landing a booster rocket and creating reusability. Unbelievable.
Similar threads
