F9 Block 5 is turning into quite a capable machine...QuoteIn terms of trends, Shotwell sees a trend of a bifurcation in the market. She says there are a couple of satellite providers making their satellites bigger. “Some of that is basically putting a giant satellite on Falcon 9 with a lot of propellant, which would normally be a very heavy satellite, even potentially hard for Falcon 9 to throw. But when you put so much propellant on that satellite, they can get themselves to orbit even from a sub-synch. A couple of manufacturers are doing that … [sending] an over 7-ton satellite on Falcon 9 to GTO. We are seeing a number of satellite manufacturers come around and do that just because of the value proposition presented by Falcon 9.”http://interactive.satellitetoday.com/via/april-2017/shotwell-ambitious-targets-achievable-this-year/
In terms of trends, Shotwell sees a trend of a bifurcation in the market. She says there are a couple of satellite providers making their satellites bigger. “Some of that is basically putting a giant satellite on Falcon 9 with a lot of propellant, which would normally be a very heavy satellite, even potentially hard for Falcon 9 to throw. But when you put so much propellant on that satellite, they can get themselves to orbit even from a sub-synch. A couple of manufacturers are doing that … [sending] an over 7-ton satellite on Falcon 9 to GTO. We are seeing a number of satellite manufacturers come around and do that just because of the value proposition presented by Falcon 9.”
Basically you are saying that it makes sense to develop a kick stage (small third stage) for F9.
B5 will absolutely add performance. Block 5 figures are on the website now, and SpaceX has not approached those, yet. Thrust increases for certain.
Quote from: Robotbeat on 05/08/2017 12:57 pmB5 will absolutely add performance. Block 5 figures are on the website now, and SpaceX has not approached those, yet. Thrust increases for certain.Website thrust figures are still 171,000lbf -- Block 5 was 190,000lbf, right?
Website thrust figures are still 171,000lbf -- Block 5 was 190,000lbf, right?
- Parts that are easier to produce or easier to assemble- Production and asaembly optimizations
Quote from: ChrML on 05/08/2017 12:51 pm- Parts that are easier to produce or easier to assemble- Production and asaembly optimizationsActually, reuse makes these factors less important than for an expendable. Expendable rockets need to be produced as cheaply as possible, as they can only be sold once. A reusable rocket can be harder to assemble with parts that are more difficult/expensive to make. Because that cost is amortized over many launches.For example the new titanium grid fins are probably harder to make than the aluminum ones. But since they won't slag on reentry, it's worth it.
Quote from: Norm38 on 05/10/2017 04:18 pmQuote from: ChrML on 05/08/2017 12:51 pm- Parts that are easier to produce or easier to assemble- Production and asaembly optimizationsActually, reuse makes these factors less important than for an expendable. Expendable rockets need to be produced as cheaply as possible, as they can only be sold once. A reusable rocket can be harder to assemble with parts that are more difficult/expensive to make. Because that cost is amortized over many launches.For example the new titanium grid fins are probably harder to make than the aluminum ones. But since they won't slag on reentry, it's worth it.Especially if they save time during post-launch turnaround. Inspecting grid fins and determining if they needed to be replaced each launch adds time... as does replacing them. Forged titanium could be an install once and forget item.
My burning question ...
My burning question about refurbished boosters is along the lines of "once it is refurbished once, does it require the same level of refurbishment again for its third flight?". My completely uninformed speculation is that refurbishing a block 3 makes it into something else entirely, not block 3 anymore, and not block 4, and I don't want to muddy the waters any further so I'll leave it at that, "something else". Once it is a "something else" version, could it be that the refurb is now down near the fabled "gas-n-go" levels? I think they will still not be there until the first block 5.3 (the .3 is intended to indicate the third flight of a true block 5-off-the-assembly-line booster, not a revision within the block), but that we may be seeing the first hints of that in the reflown boosters. I will be watching 1029.2/BulgariaSat with great interest, 1029.3 could be very informative. It's almost a shame that 1021.2/SES-10 got to retire (visiting this core wherever it ends up is now officially on my bucket list, however). I also think that the FH side boosters are intended to fly several times in their current configs ("something else"), and I suspect that we will see some very fast turnaround times on those, and higher flight counts than the other reflown block 3 cores.To keep this all more closely related to the block 5 OP, one thing I haven't heard much about is that block 5 could be the lightest core yet. They have launched enough times, and assumingly kept the stages heavily instrumented, and overbuilt in some ways. Wouldn't block 5 be the perfect time to finally strip out some of the excess and cut down to "fighting weight" so to speak? The data has been gathered, the results are in, the design is more or less "locked" in block 5 right? I'm not proposing drastic cuts to structural margins, but there must be something they can trim to eke a little more pmf rather than just relying on thrust increases or prop densification.I think what I'm proposing here is that similar to Intel, block 4 may be a "tick" cycle (increase performance/capability) and block 5 may be the "tock" (refinement/streamline) cycle. Did we already see this with 1.1 -> 1.2 and didn't realize it? Or were there simply too many changes all at once to put labels like that on those revisions?
Isn't that what we do here?