Quote from: DJPledger on 02/18/2014 07:43 pmQuote from: cambrianera on 02/18/2014 07:36 pmThe drought of news from SpaceX is awful.The effects on NSF members are: loss of memory, confusion, disbelief, general uneasiness. SpaceX are getting as secretive as Blue Origin these days. We all wish SpaceX could become open again like they were in their early days. The lack of SpaceX news is definitely getting everyone on edge.They are now doing stuff that is either innovative, and thus requires ITAR and trade secrets compliance, or they not doing so well and thus nothing to talk about.
Quote from: cambrianera on 02/18/2014 07:36 pmThe drought of news from SpaceX is awful.The effects on NSF members are: loss of memory, confusion, disbelief, general uneasiness. SpaceX are getting as secretive as Blue Origin these days. We all wish SpaceX could become open again like they were in their early days. The lack of SpaceX news is definitely getting everyone on edge.
The drought of news from SpaceX is awful.The effects on NSF members are: loss of memory, confusion, disbelief, general uneasiness.
SpaceX are getting as secretive as Blue Origin these days.
Did anyone ever discover that the Merlin D nozzle diameter is?
F9 (both v1.0 and v1.1) has an interior LOX standpipe which runs from the center of the common dome down through the fuel dome and to the engine bay. You can just see it in red in the attached image (from v1.0).
Ah so it is surrounded by the kerosene then. Neat, does it help structurally as well?
Would you know why Zenit uses a toroidal tank then?
I have a question: I haven't seen any fuel lines on the outside of the vehicle to direct the propellant in the upper tank of the stage to the engine. The ariane V does this via a fuel line on the outside, the Atlas V as well, the Zenit has a toroidal kerosene tank and the oxidizer line goes through its center. What does the F9 do, does it have a toroidal tank as well?
why Zenit uses a toroidal tank then?
I think this is another example of how SpaceX designed the F9 (and the v1.1 even more so) with reusability in mind, since a clean exterior profile would be important for surviving re-entry.
Quote from: Lars_J on 02/19/2014 05:15 pmI think this is another example of how SpaceX designed the F9 (and the v1.1 even more so) with reusability in mind, since a clean exterior profile would be important for surviving re-entry.and horizontal processing.
With 17.5% more thrust (if Elon Musks 85% is believable), I am wondering if they could simply fly a sort of 8 engine configuration (a sort of hepta- web with one in the middle). That would probably save quite a bit of weight on the stage. The problem is of course that you loose symmetry (you wont have 3 engines in a line), which could be a problem for first stage recovery. But reducing the number of engines and thus shedding off weight seems like a good way to increase the amount of payload they can deliver to orbit. A 17.5% increase in thrust is unfortunately just a little short of allowing a 7 engine configuration (about 8% less thrust than the current 9 engine configuration), which would have definitely shed a lot of weight of the first stage and would also have the 3 engines in a line.
Elon mentioned 165klb vs 147klb - more like 12% than the 17% implied.
and we're only actually operating the engines at about 85% of their potential
Jeff Foust @jeff_foust · Feb 21 Reisman: hope to have F9 1st stage do a powered landing with a year. 2nd stage reuse much harder, still being studied. #spaceuphouJeff Foust @jeff_foust · Feb 21 Reisman: 39A at KSC will be for crewed missions & Falcon Heavy; 40 for other government missions; comm'l launches from new site. #spaceuphouJeff Foust @jeff_foust · Feb 21 Reisman: SpaceX plans to eventually launch 20 rockets a year, 10 Falcon 9 and 10 Falcon Heavy. #spaceuphou