Quote from: rakaydos on 05/04/2017 08:38 amITS cant use the falcon pads anyway, so there's no reason to shut down the falcon pads to add methlox.The current plan for ITS is launching from 39A, which just happens to be a Falcon pad. At least acknowledge the clearly stated plan before speculating the complete opposite.
ITS cant use the falcon pads anyway, so there's no reason to shut down the falcon pads to add methlox.
If you take a few days to understand the business side of things, you'll see that this whole raptor upper stage endeavour could make a lot of sense technically, but makes ZERO sense when you consider $$$.
Elon Musk has said several times, that he doesn't care too much about profit, but that if his companies don't at least nearly break even, he can't justify them to investors and the whole effort become a house of cards.Remember Musk has two degrees, Physics and Economics. He seems to use both skills very wisely.
Quote from: envy887 on 05/04/2017 12:42 pmQuote from: rakaydos on 05/04/2017 08:38 amITS cant use the falcon pads anyway, so there's no reason to shut down the falcon pads to add methlox.The current plan for ITS is launching from 39A, which just happens to be a Falcon pad. At least acknowledge the clearly stated plan before speculating the complete opposite.That's a concept. It can't be "the plan" because LC-39A can't handle the thrust a BFR would produce. 39A would have to be stripped down, dug out, and completely rebuilt to fly the BFR. It would be cheaper and easier to build a new pad.
Quote from: whitelancer64 on 05/04/2017 08:49 pmQuote from: envy887 on 05/04/2017 12:42 pmQuote from: rakaydos on 05/04/2017 08:38 amITS cant use the falcon pads anyway, so there's no reason to shut down the falcon pads to add methlox.The current plan for ITS is launching from 39A, which just happens to be a Falcon pad. At least acknowledge the clearly stated plan before speculating the complete opposite.That's a concept. It can't be "the plan" because LC-39A can't handle the thrust a BFR would produce. 39A would have to be stripped down, dug out, and completely rebuilt to fly the BFR. It would be cheaper and easier to build a new pad.I've seen this repeated many times, but never with any kind of actual data to support it. Surely that data or a way to calculate it exists somewhere. Can you provide a reference?
Quote from: envy887 on 05/04/2017 09:10 pm...I've seen this repeated many times, but never with any kind of actual data to support it. Surely that data or a way to calculate it exists somewhere. Can you provide a reference?Doesn't exactly say either way, but here's an interesting quote from an NSF article:"The rocket is shown to be launching from SpaceX’s 39A launch site, which was in doubt based on its thrust margins. However, the rocket is close to the limitations of the pad’s 28 million pound parameter and is likely to be provided with a level of pad engineering mitigation to allow ITS to launch from this site."https://www.nasaspaceflight.com/2016/09/spacex-reveals-mars-game-changer-colonization-plan/
...I've seen this repeated many times, but never with any kind of actual data to support it. Surely that data or a way to calculate it exists somewhere. Can you provide a reference?
Quote from: rakaydos on 05/03/2017 09:18 pmIt does provide some benifit, before ITS comes online. But once ITS comes online it's entirely obsolite, which puts a cap on how much it can earn for SpaceX over what the Mvac stage can. And it's pretty clear that how much it can earn is less than how much it would cost to develop and build that stage, rebuild a launch site for mixed propellants (displacing normal paying flights, which counts as a cost), and other expences of such a program.How much it can earn? That's spoken like someone who hasn't heard that SpaceX would very much like to orbit 10K+ satellites.Who cares about their paying flights, when to launch 4400 LEO sats they themselves will need almost 90 Falcon Heavy launches at 50 sats per FH launch? That's three times the number of current *F9* flights and almost as many as the current number of Atlas V and Delta 4 flights combined. Double that or more if they're restricted to launching them on F9s due to lack of fairing volume (a topic for another thread).And then there's also another 7000-odd VLEO sats, so double or triple the 90 FH or 180 F9 flights.At this point, SpaceX's commercial *paying* flights are a somewhat rough rounding error.A Raptor S2 doesn't need to earn SpaceX a thing when at $10M per Merlin S2, 200 or 300 launches represents a couple or three billion of capital just in Merlin S2s -- and never mind the CommX payloads. It's possible SpaceX could save a good portion of that by developing a fully reusable upper stage. A billion saved is a billion earned -- isn't that how the saying goes?And a Raptor stage won't eat performance margins for lunch like the relatively low ISP Merlin upper stage will -- a 20-30% performance penalty to the current S2 would, at flight rates of 200-300 launches, mean 40 on the low end and 90 on the high end more launches. Even assuming a heavily discounted $30M per FH launch, 40 launches is again over $1 billion in additional costs. At a discounted $20M per F9, 90 launches is almost $2B.Quote from: rakaydos on 05/04/2017 08:38 amThe problem is that the "things it does that falcon cant" isnt big enough to cover even "Doesnt cost that much," especially since infrastructure changes (fuel lines on the erector, ect) actually would -reduce- the number of paying flights compared to a kerlox-only falcon family.Unfortunately, "things Falcon can't" currently include launching 10K+ sats in as economical a manner as SpaceX likely needs if Elon wants to maintain control of the company.Compared to current flight rates, a few hundred million to design and build a Raptor upper stage (hopefully with integrated sat dispenser, which, indeed, may look like a mini-ITS) and a couple hundred more to modify the GSE is blinking expensive.Compared to what SpaceX plans, however, it's practically peanuts. You need to keep in mind that, if you're trying to suss out what SpaceX is going to do, SpaceX will act based on the requirements of their own dreams and schemes -- which most certainly include the CommX constellation.And those plans present SpaceX with a stark choice: a fully reusable Raptor upper stage, a reusable Merlin upper stage that adds 40 or 60 or 80 launches to a manifest that already strains credulity, or an expendable Merlin that results in $2-3 billion of SpaceX cash burned up on re-entry.If after all's said and done, it costs SpaceX $1 billion to field a Raptor upper stage, well, even to a billionaire like Musk saving another billion in costs isn't chump change.
It does provide some benifit, before ITS comes online. But once ITS comes online it's entirely obsolite, which puts a cap on how much it can earn for SpaceX over what the Mvac stage can. And it's pretty clear that how much it can earn is less than how much it would cost to develop and build that stage, rebuild a launch site for mixed propellants (displacing normal paying flights, which counts as a cost), and other expences of such a program.
The problem is that the "things it does that falcon cant" isnt big enough to cover even "Doesnt cost that much," especially since infrastructure changes (fuel lines on the erector, ect) actually would -reduce- the number of paying flights compared to a kerlox-only falcon family.
I think they used Pad 39A in the video because it's iconic. My issue with using 39A is simply why would they take their FH and crew pad out of service to repurpose it? Why not just build a new pad? Otherwise they need to upgrade LC40 for FH, add a crew access tower and arm. It makes no sense to me.
Quote from: macpacheco on 05/04/2017 11:07 amhave ZERO problems raising capital for either SpaceX or Tesla.Capital for things investors hope to profit from. Like the Internet constellation.If you have evidence of SpaceX receiving funding from philanthropic billionaires, I'd really like to hear about it.
have ZERO problems raising capital for either SpaceX or Tesla.
Quote from: mme on 05/04/2017 09:59 pmI think they used Pad 39A in the video because it's iconic. My issue with using 39A is simply why would they take their FH and crew pad out of service to repurpose it? Why not just build a new pad? Otherwise they need to upgrade LC40 for FH, add a crew access tower and arm. It makes no sense to me.The revenue lost could be less than the cost of building a new pad.
I think raptor upper stage is off the table....until there is money in producing such a thing....
Quote from: corneliussulla on 05/05/2017 06:58 amI think raptor upper stage is off the table....until there is money in producing such a thing....With the upcoming satellite constellation there is a lot of money in a reusable upper stage that does not reduce present capability of the Falcon family.
Quote from: guckyfan on 05/05/2017 07:09 amQuote from: corneliussulla on 05/05/2017 06:58 amI think raptor upper stage is off the table....until there is money in producing such a thing....With the upcoming satellite constellation there is a lot of money in a reusable upper stage that does not reduce present capability of the Falcon family.LEO communications satellites are very light, and the payload capasity is often not the bottleneck; the bottleneck might be different destination orbits required and/or fairing volume.Then can recover merlin 1d-based second stage while still launching MANY satellites per launch, and methane-based upper stage might just make price/satellite more expensive due more complex launch site needed.For big GTO/BEO payloads, methane-based second stage would help.
Negan, Pad 39A's thrust limit is 12 million lbs. (Originally designed for a Nova Class rocket, with 8 F-1 engines). ITS proposed 28 million will not launch from 39A. It will require a new launch pad. This is why all the talk of a Raptor upper stage. With FH coming on line, and a proposed reusable upper stage late this year, there is speculation of a Raptor based upper stage, giving FH about 10 tons extra payload to LEO. This would put it in the lower range of the SLS which was to be 70-130 tons to LEO with upgrades. A Raptor upper stage might be a little too large for F9, but not for FH. If it is a Raptor upper stage, it would need to be reusable, and test various components for future ITS.