Quote from: woods170 on 09/25/2013 04:36 pmQuote from: neoforce on 09/25/2013 04:18 pm- what does "radiation shielding" mean? Heat shielding (if there is only 3 engines on F9R-1) I could understand. But radiation shielding?-Heat is just another form of radiation. That is, if you consider radiation as electromagnetic radiation. The electromagnetic spectrum holds all forms of electromagnetic radiation from below the low frequences of radio all the way up to the high frequency gamma radiation. All other forms of electromagnetic radiation, including heat (= infrared) are in between those two extremes.Shielding the bottom part of the rocket against heat is actually shielding the rocket from infrared radiation.Technically correct, but the phrase "radiation shielding" as applied to space systems usually connotes high frequency EM/particle radiation, not heat transfer. It's not typically used to describe thermal protection, which is what this appears to be.
Quote from: neoforce on 09/25/2013 04:18 pm- what does "radiation shielding" mean? Heat shielding (if there is only 3 engines on F9R-1) I could understand. But radiation shielding?-Heat is just another form of radiation. That is, if you consider radiation as electromagnetic radiation. The electromagnetic spectrum holds all forms of electromagnetic radiation from below the low frequences of radio all the way up to the high frequency gamma radiation. All other forms of electromagnetic radiation, including heat (= infrared) are in between those two extremes.Shielding the bottom part of the rocket against heat is actually shielding the rocket from infrared radiation.
- what does "radiation shielding" mean? Heat shielding (if there is only 3 engines on F9R-1) I could understand. But radiation shielding?-
Delta IV's production was also designed for 40 cores/year.BTW, they're test-firing engines nearly every day at McGregor I hear. They can test two at once.
Cool thread and article. I especially like the photos of the Grasshopper 2. Article name is great too. I wonder if the name of the rocket factory could be changed to "The Rookery".
..It's been suggested that F9R-1 will have only three engines, which would seem to jibe with the photo.
How the devil do you build, certify, test fire, & integrate 182 rocket engines a year, much less 400.
Quote from: Kabloona on 09/25/2013 04:31 pm..It's been suggested that F9R-1 will have only three engines, which would seem to jibe with the photo.Yes, agree. It looks like the centre engine is still to be installed.I thought the idea of the octaweb was that all 9 engines would be mounted on it prior to integration with the stage. This doesn't seem to be the case for F9R-1, unless they are going with only two engines, which seems unlikely, since the centre one is used for landing. But this stage is a special article so I guess its assembly sequence might be different from a standard stage.
Quote from: go4mars on 09/25/2013 05:30 pmCool thread and article. I especially like the photos of the Grasshopper 2. Article name is great too. I wonder if the name of the rocket factory could be changed to "The Rookery". Thanks! I was, however, someone would have photoshopped it by now, with the stages having baby faces, one crying, one with a dummy/pacifier, another doing that weird baby laugh face..........but that's just me
Assuming "cores" encompasses both first and second stages, and that SpaceX might eventually have three FH launches/yr: - 3xFH: 12 cores using 81 M1D and 3 M1D-Vac - 14xF9: 28 cores using 126 M1D and 14 M1D-VacTotal engine count under this would be 207 M1D + 17 M1D-Vac = 224 engines.That's not such a huge number to keep moving through a production line. It would keep MacGregor reasonably busy though if test-firing every engine - every week 4 or 5 production engines arrive for testing, as well as any development tests.
Quote from: Joffan on 09/25/2013 04:29 pmAssuming "cores" encompasses both first and second stages, and that SpaceX might eventually have three FH launches/yr: - 3xFH: 12 cores using 81 M1D and 3 M1D-Vac - 14xF9: 28 cores using 126 M1D and 14 M1D-VacTotal engine count under this would be 207 M1D + 17 M1D-Vac = 224 engines.That's not such a huge number to keep moving through a production line. It would keep MacGregor reasonably busy though if test-firing every engine - every week 4 or 5 production engines arrive for testing, as well as any development tests.I had always understood SpaceX to use the term "core" to mean something with nine engines -- a first stage of a Falcon 9 or one of the three parallel lower stages of a Falcon Heavy. I didn't think it included upper stages.So, 10 Falcon 9 plus 10 Falcon Heavy launches a year is 40 cores. And I believe 10 F9 plus 10 FH launches is what SpaceX has said before they are targeting.They've also talked about a production rate of 400 Merlin 1 engines a year, which would be just about right for 10 F9 plus 10 FH -- 380 engines for the 20 launches, plus 20 spares.
Quote from: BrianNH on 09/25/2013 04:30 pmQuoteAccording to L2 information, the only noticeable differences in the Crew Dragon weldment are that the aft cylinder is a few inches longer than on Cargo, and there are clevises machined into the edge of the forward bulkhead to receive SuperDraco thrusters.Does this mean that SuperDracos will be used only on Crewed Dragon and not Cargo Dragon?Not used on the current version of Cargo Dragon (i.e. not for CRS missions). SpaceX plan for Cargo Dragon to eventually use SuperDracos. Think 2016 timeframe.
QuoteAccording to L2 information, the only noticeable differences in the Crew Dragon weldment are that the aft cylinder is a few inches longer than on Cargo, and there are clevises machined into the edge of the forward bulkhead to receive SuperDraco thrusters.Does this mean that SuperDracos will be used only on Crewed Dragon and not Cargo Dragon?
According to L2 information, the only noticeable differences in the Crew Dragon weldment are that the aft cylinder is a few inches longer than on Cargo, and there are clevises machined into the edge of the forward bulkhead to receive SuperDraco thrusters.
This means cargo dragons could have a LAS also. Nice if transporting very valuable cargo!
Quote from: Jcc on 09/26/2013 11:05 amThis means cargo dragons could have a LAS also. Nice if transporting very valuable cargo!That would require the cargo to be able to withstand the high G-force on escape and the packing for that. I think the advantage would be more in powered landing, easy recovery of downmass and easy reuse of the Dragon.
If you're willing to give up payload in place of it.
Quote from: Mike_1179 on 09/26/2013 12:29 pmIf you're willing to give up payload in place of it.If the rocket is in the process of deflagrating I think the payload will too if you don't use the LAS.
Regardless if the the LAS is used to save cargo there may be some manufacturing and economic benefits in having as few differences between the different Dragon versions as possible.