Merlin 1D uses a method called “Phase shut off”, removes most valves reducing chances of failure by removing components and removing a lot of risk of a hard start.
Retractable landing gear must be intended for use with the landing pad robot (Roomba). Otherwise, erroneous retraction of landing gear while on the ground is a bad day which happens from time to time in aviation.
QuoteAnd it’s going to have a much better landing legs that just fold up and; just drop the rocket, fold the legs, ship it, fold the legs out when it lands. Making it turn very fast;
And it’s going to have a much better landing legs that just fold up and; just drop the rocket, fold the legs, ship it, fold the legs out when it lands. Making it turn very fast;
For instance, Block 5 has reusable TPS on the bottom. I suspected as much as they're hiring carbon-carbon engineers, and that's perhaps the most obvious use for carbon-carbon (other than perhaps a nozzle extension on the upper stage?).
There were a lot of what seemed like very important, or at least highly interesting, parts that were obliterated by transmission errors. A couple of his anecdotes were getting right to the part I most wanted to hear when the audio dropped until he was finished. I suppose whatever he was saying is lost for good?
Review the Transcript Zucal posted above.
Top SpaceX employee throws shade at just about all of his competitorsThe price that government programs “charge for their rockets is just ridiculous.”by Eric Berger - May 14, 2017 1:24am BST
We actually picked the wrong propellant. It wasn’t too bad, but we picked RP-1, rocket-grade kerosene, which at the time was, you know, 8 dollars a gallon. We tried jet fuel, which is more like 2 dollars a gallon, but it just didn’t run very good. But recently, we re-negotiated the cost of the kerosene fuel and we got it close to the cost of jet fuel.
Power on Mars- fission is the way to go but will have to be solar initially.Need solar panels covering 4 football fields to make fuel for the trip home over 2 years, and keep dust off them.SpaceX is just offering a cheap ticket to Mars, it will take other companies, investors, governments to make everything else.
Tom's talk starting to get media attention:QuoteTop SpaceX employee throws shade at just about all of his competitorsThe price that government programs “charge for their rockets is just ridiculous.”by Eric Berger - May 14, 2017 1:24am BSThttps://arstechnica.com/science/2017/05/a-top-spacex-employee-throws-shade-at-just-about-all-of-his-competitors/
Given the cost goal Elon gave him for the Merlin 1D, depending on how close he got, those engines could be a whole lot cheaper than people have estimated them to be. That was a pretty seriously low price he was targeting.
I'm just glad to see that someone with so much influence in today's space development has such a huge night and day difference in attitude compared to the status quo of most of the experts on this forum.
Quote from: Daniels30 on 05/13/2017 11:34 pmMerlin 1D uses a method called “Phase shut off”, removes most valves reducing chances of failure by removing components and removing a lot of risk of a hard start.I think he means "face shutoff", meaning propellants are "shut off" at the injector face.See e.g. http://www.rocket-propulsion.info/resources/articles/TRW_PINTLE_ENGINE.pdf.
And, uh, I’ve seen that hurt us before, I’ve seen that fail, but I’ve also seen— where nobody thought it would work— it was the right decision. It was the harder way to do it, but in the end, it was the right thing. One of the things that we did with the Merlin 1D was; he kept complaining— I talked earlier about how expensive the engine was. <inaudible> [I said,] “[the] only way is to get rid of all these valves. Because that’s what’s really driving the complexity and cost.” And how can you do that? And I said, “Well, on smaller engines, we’d go phase-shutoff, but nobody’s done it on a really large engine. It’ll be really different.” And he said, “We need to do phase-shutoff. Explain how that works?” So I drew it up, did some, you know, sketches, and said “here’s what we’d do,” and he* said “That’s what we need to do.” And I advised him against it; I said it’s going to be too hard to do, and it’s not going to save that much. But he made the decision that we were going to do phase-shutoff.So we went and developed that engine; and it was hard. We blew up a lot of hardware. And we tried probably tried a hundred different combinations to make it work; but we made it work.
Quote from: FutureSpaceTourist on 05/14/2017 05:31 amTom's talk starting to get media attention:QuoteTop SpaceX employee throws shade at just about all of his competitorsThe price that government programs “charge for their rockets is just ridiculous.”by Eric Berger - May 14, 2017 1:24am BSThttps://arstechnica.com/science/2017/05/a-top-spacex-employee-throws-shade-at-just-about-all-of-his-competitors/Eric is just highliting the controversial stuff of a very interesting interview. It does not help to have more of these in the future. The foldable legs, F9 24 hour turn around in few months (as a matter of HR costs, not much on time), Tesla factory using coke manufacturing as a model (physical limits of machinery), Merlin D strategy.... are FMPOV much more interesting parts of the interview. Don't let the reality spoil a good headline.
One nugget I found interesting was when he was talking about the CommX constellation(s), he said something to the effect, 'Now imagine that you could deploy these with a rocket that can put hundreds of tons into orbit at a time...'. I guess that solidly confirms SpaceX's plans to use the ITS (as opposed to, say, FH) as the main vehicle to deploy CommX. Though that presents a bit of chicken/egg problem, as I think Musk had previously indicated that they needed CommX revenues to help pay development costs for ITS.
Quote from: GORDAP on 05/14/2017 01:09 pmOne nugget I found interesting was when he was talking about the CommX constellation(s), he said something to the effect, 'Now imagine that you could deploy these with a rocket that can put hundreds of tons into orbit at a time...'. I guess that solidly confirms SpaceX's plans to use the ITS (as opposed to, say, FH) as the main vehicle to deploy CommX. Though that presents a bit of chicken/egg problem, as I think Musk had previously indicated that they needed CommX revenues to help pay development costs for ITS.Unless constellation 2.0 will use much larger satellites, but still as many.Remember the statistics on how fast data traffic is growing, and factor in self driving cars and other upcoming developments, and constellation capability will have to grow accordingly...
There wasn't actually a lot new in here. A lot of the stuff was extrapolatable.A lot of the "new" content is simply taking stuff Musk has already said seriously.
His examples about the Merlin have some interesting numbers:About 1000 lbs engine mass. Roughly 450 kg, which is a bit lower than the previous estimates I've seen.About 800 lbs/s propellant mass flow rate. That's about 360 kg/s, which is quite a bit higher than the 275 to 300 kg/s typically quoted for Merlin.About 10,500 ft/s exhaust velocity. He also says about Mach 10 exhaust velocity. Those are 3200 and 3400 m/s or 325/345 second ISP. These don't add up to the stated thrust of Falcon 9, which is 7606 kN. With those flow rates and velocities it would be 10000 kN or 11000 kN.But maybe Merlin is considerably more capable than we expected?
Quote from: envy887 on 05/14/2017 02:21 pmHis examples about the Merlin have some interesting numbers:About 1000 lbs engine mass. Roughly 450 kg, which is a bit lower than the previous estimates I've seen.About 800 lbs/s propellant mass flow rate. That's about 360 kg/s, which is quite a bit higher than the 275 to 300 kg/s typically quoted for Merlin.About 10,500 ft/s exhaust velocity. He also says about Mach 10 exhaust velocity. Those are 3200 and 3400 m/s or 325/345 second ISP. These don't add up to the stated thrust of Falcon 9, which is 7606 kN. With those flow rates and velocities it would be 10000 kN or 11000 kN.But maybe Merlin is considerably more capable than we expected?It seemed like he was just pulling approximate numbers off the cuff. I would not read too much into that.
Quote from: Basto on 05/14/2017 03:36 pmQuote from: envy887 on 05/14/2017 02:21 pmHis examples about the Merlin have some interesting numbers:About 1000 lbs engine mass. Roughly 450 kg, which is a bit lower than the previous estimates I've seen.About 800 lbs/s propellant mass flow rate. That's about 360 kg/s, which is quite a bit higher than the 275 to 300 kg/s typically quoted for Merlin.About 10,500 ft/s exhaust velocity. He also says about Mach 10 exhaust velocity. Those are 3200 and 3400 m/s or 325/345 second ISP. These don't add up to the stated thrust of Falcon 9, which is 7606 kN. With those flow rates and velocities it would be 10000 kN or 11000 kN.But maybe Merlin is considerably more capable than we expected?It seemed like he was just pulling approximate numbers off the cuff. I would not read too much into that.TM breathes this stuff. I'd take him literally before believing our numbers to the slightest degree.
Quote from: meekGee on 05/14/2017 01:19 pmQuote from: GORDAP on 05/14/2017 01:09 pmOne nugget I found interesting was when he was talking about the CommX constellation(s), he said something to the effect, 'Now imagine that you could deploy these with a rocket that can put hundreds of tons into orbit at a time...'. I guess that solidly confirms SpaceX's plans to use the ITS (as opposed to, say, FH) as the main vehicle to deploy CommX. Though that presents a bit of chicken/egg problem, as I think Musk had previously indicated that they needed CommX revenues to help pay development costs for ITS.Unless constellation 2.0 will use much larger satellites, but still as many.Remember the statistics on how fast data traffic is growing, and factor in self driving cars and other upcoming developments, and constellation capability will have to grow accordingly...Admittedly, it's been a while since I last looked through the FCC database, but I don't think they've even approved constellation 1.0. All the spacecraft general physical details, nominal orbital elements for each plane, RF characteristics at ground level for each altitude, etc. have to be detailed by the applicant, reviewed by the FCC (and arguably the ITU if service is being performed outside of FCC jurisdiction), and then approved before the constellation can begin operating.If SpaceX is going to massively revise the plans for their satellites, there will be a several year regulatory lag from the time they make their plans to the time the can make good on those plans ... I don't think SpaceX is the kind of organization that likes being behind that kind of curve.
Quote from: Jimmy Murdok on 05/14/2017 08:15 amQuote from: FutureSpaceTourist on 05/14/2017 05:31 amTom's talk starting to get media attention:QuoteTop SpaceX employee throws shade at just about all of his competitorsThe price that government programs “charge for their rockets is just ridiculous.”by Eric Berger - May 14, 2017 1:24am BSThttps://arstechnica.com/science/2017/05/a-top-spacex-employee-throws-shade-at-just-about-all-of-his-competitors/Eric is just highliting the controversial stuff of a very interesting interview. It does not help to have more of these in the future. The foldable legs, F9 24 hour turn around in few months (as a matter of HR costs, not much on time), Tesla factory using coke manufacturing as a model (physical limits of machinery), Merlin D strategy.... are FMPOV much more interesting parts of the interview. Don't let the reality spoil a good headline.Yes, Eric is doing a huge disservice to all of space media reporting by posting such absurd comments. He should retract such articles. He's writing hit pieces to get clicks rather than to actually inform. Shame on him.
So once we’re flying that, all other rockets will probably be obsolete. <laughs>
Quote from: Basto on 05/14/2017 03:36 pmQuote from: envy887 on 05/14/2017 02:21 pmHis examples about the Merlin have some interesting numbers:About 1000 lbs engine mass. Roughly 450 kg, which is a bit lower than the previous estimates I've seen.About 800 lbs/s propellant mass flow rate. That's about 360 kg/s, which is quite a bit higher than the 275 to 300 kg/s typically quoted for Merlin.About 10,500 ft/s exhaust velocity. He also says about Mach 10 exhaust velocity. Those are 3200 and 3400 m/s or 325/345 second ISP. These don't add up to the stated thrust of Falcon 9, which is 7606 kN. With those flow rates and velocities it would be 10000 kN or 11000 kN.But maybe Merlin is considerably more capable than we expected?It seemed like he was just pulling approximate numbers off the cuff. I would not read too much into that.He gave three significant digits for the exhaust velocity. If that was just making up numbers, I'd expect 10,000 not 10,500.
Quote from: butters on 05/14/2017 01:15 amRetractable landing gear must be intended for use with the landing pad robot (Roomba). Otherwise, erroneous retraction of landing gear while on the ground is a bad day which happens from time to time in aviation.Power fold was NOT indicated... Not my take anyway from Tom's statements... Manual unlatch and manual fold (I assume with some GSE involved) was hinted at... Key take away... is leaving the legs on to save in turn around time... Added quote from transcript...QuoteQuoteAnd it’s going to have a much better landing legs that just fold up and; just drop the rocket, fold the legs, ship it, fold the legs out when it lands. Making it turn very fast;
QuoteSo once we’re flying that, all other rockets will probably be obsolete. <laughs>I bet Rogozin doesn't laugh
The Russians are saying they’re coming up with a rocket that can beat SpaceX, which is entertaining, <laughs> which is entertaining, because they’ve been working on their Angara rocket for 22 years, and launched it once. And suddenly they’re going to be coming up with a low-cost one.
The comments from Mueller gives the impression that the M1D has hit all three items instead of just 2 in the cost, performance, reliability tradeoff. This is in itself very significant and also important for SpaceX. They have a very low cost engine with high performance and high reliability. Something that no one else in the US industry has even come close to. Which is why the Atlas V uses the low cost, high performance, high reliability RD-180 from Russia, the only other engine in use in the US that hits all three points.This goal of hitting all three for the Raptor is also encouraging. Using lessons learned and piling the difficulty into development to be able to make such an engine instead of compromising on operational costs to keep development costs down. Musk has it right. If your going to fly lots of them and want to lower operational costs have good or high performance and high reliability, don't push off doing the right things in development for reducing the development costs.
That rocket is going to be the real game-changer. I would say that the Falcon 9 is revolutionary, you know, a reusable rocket that greatly reduces the cost of access to space. Maybe we can achieve ten reduction in cost over, you know, like what ULA or the Russians or the Chinese are doing, with the Falcon. But we want like a hundred or more reduction in costs; and that’s what the Mars rocket’s gonna do. That’s going to be the revolutionary rocket.So once we’re flying that, all other rockets will probably be obsolete. <laughs>
Combustion efficiency is not actual energy-in (fuel chemical energy), energy-out (jet kinetic energy) efficiency. On that latter measure of efficiency, Raptor is 40-60% efficient.
These don't add up to the stated thrust of Falcon 9, which is 7606 kN. With those flow rates and velocities it would be 10000 kN or 11000 kN.But maybe Merlin is considerably more capable than we expected?
Quote from: Robotbeat on 05/14/2017 09:09 pmCombustion efficiency is not actual energy-in (fuel chemical energy), energy-out (jet kinetic energy) efficiency. On that latter measure of efficiency, Raptor is 40-60% efficient.So, what does the 99% efficiency refer to? ...fraction of hypothetical max. ISP achieved?
I get almost 61% efficiency for a 382s Isp, 3.8 oxidizer to fuel mass ratio, and 55.5MJ/kg specific energy for methane. Check my work..5*(382*9.80665m/s)^2/(55.5MJ/(4.8kg))http://tinyurl.com/kxc9so2
This interview is a gold mine of information. Not sure everybody realizes what *Tom* is presenting here. I'm working on a summary to be released shortly. This covers SpaceX, the SpaceX satellite business, Tesla and more. The whole idea that SpaceX is the "airline" to Mars and other companies will have to participate to have car rentals, hotels and other attractions is * AWESOME!*This is crazy!
The talk about nuclear thermal rockets isn't too surprising, either. We know already that SpaceX had been considering NTR at one point due to past presentations (most of them many years old, now). I feel this is a Mueller thing, as Mueller is maybe /the/ greatest propulsion engineer on the planet right now, and NTR is pretty tantalizing. I mean, we actually built them in the past and designed even better ones. (BTW, I think the conclusion is a good one: too expensive for what SpaceX wants to do now.) If you're a propulsion engineer that isn't super old, you might chafe a bit at the fact that you weren't around at the time when these things were being developed (potentially) for flight.
Quote from: gospacex on 05/14/2017 05:54 pmQuoteSo once we’re flying that, all other rockets will probably be obsolete. <laughs>I bet Rogozin doesn't laugh Especially at this part:QuoteThe Russians are saying they’re coming up with a rocket that can beat SpaceX, which is entertaining, <laughs> which is entertaining, because they’ve been working on their Angara rocket for 22 years, and launched it once. And suddenly they’re going to be coming up with a low-cost one.That would officially be considered throwing shade -- on a world leader in spaceflight.
Quote from: shuttle_buff on 05/15/2017 12:39 amThis interview is a gold mine of information. Not sure everybody realizes what *Tom* is presenting here. I'm working on a summary to be released shortly. This covers SpaceX, the SpaceX satellite business, Tesla and more. The whole idea that SpaceX is the "airline" to Mars and other companies will have to participate to have car rentals, hotels and other attractions is * AWESOME!*This is crazy!Most of the stuff in what he mentioned we already knew or already knew most of. This just re-confirms a lot of the stuff we knew our puts it in more clear terms.
I once got a nice tour at General Motors, as part of some automated assembly thing. The very notion of changing the heartbeat rate of a production line was sacrilegious...
Quote from: mlindner on 05/15/2017 01:06 amQuote from: shuttle_buff on 05/15/2017 12:39 amThis interview is a gold mine of information. Not sure everybody realizes what *Tom* is presenting here. I'm working on a summary to be released shortly. This covers SpaceX, the SpaceX satellite business, Tesla and more. The whole idea that SpaceX is the "airline" to Mars and other companies will have to participate to have car rentals, hotels and other attractions is * AWESOME!*This is crazy!Most of the stuff in what he mentioned we already knew or already knew most of. This just re-confirms a lot of the stuff we knew our puts it in more clear terms.I disagree. For example, we knew the number - "24 hours", but not the context around it. We didn't know about the valving scheme, and again - about the context around it."If a robot is not moving as fast as physically possible, someone is not doing their job..." - that's illuminating.I once got a nice tour at General Motors, as part of some automated assembly thing. The very notion of changing the heartbeat rate of a production line was sacrilegious...
Quote from: meekGee on 05/15/2017 02:45 amQuote from: mlindner on 05/15/2017 01:06 amQuote from: shuttle_buff on 05/15/2017 12:39 amThis interview is a gold mine of information. Not sure everybody realizes what *Tom* is presenting here. I'm working on a summary to be released shortly. This covers SpaceX, the SpaceX satellite business, Tesla and more. The whole idea that SpaceX is the "airline" to Mars and other companies will have to participate to have car rentals, hotels and other attractions is * AWESOME!*This is crazy!Most of the stuff in what he mentioned we already knew or already knew most of. This just re-confirms a lot of the stuff we knew our puts it in more clear terms.I disagree. For example, we knew the number - "24 hours", but not the context around it. We didn't know about the valving scheme, and again - about the context around it."If a robot is not moving as fast as physically possible, someone is not doing their job..." - that's illuminating.I once got a nice tour at General Motors, as part of some automated assembly thing. The very notion of changing the heartbeat rate of a production line was sacrilegious...If there are humans on the production line, changing the speed involves intense politics because you are probably torturing some of them. Hence eliminating all human touches first makes a lot of difference.
Quote from: meekGee on 05/15/2017 02:45 amQuote from: mlindner on 05/15/2017 01:06 amQuote from: shuttle_buff on 05/15/2017 12:39 amThis interview is a gold mine of information. Not sure everybody realizes what *Tom* is presenting here. I'm working on a summary to be released shortly. This covers SpaceX, the SpaceX satellite business, Tesla and more. The whole idea that SpaceX is the "airline" to Mars and other companies will have to participate to have car rentals, hotels and other attractions is * AWESOME!*This is crazy!Most of the stuff in what he mentioned we already knew or already knew most of. This just re-confirms a lot of the stuff we knew our puts it in more clear terms.I disagree. For example, we knew the number - "24 hours", but not the context around it. We didn't know about the valving scheme, and again - about the context around it."If a robot is not moving as fast as physically possible, someone is not doing their job..." - that's illuminating.I once got a nice tour at General Motors, as part of some automated assembly thing. The very notion of changing the heartbeat rate of a production line was sacrilegious...I love watching videos of incredibly fast machines. My faves are pick and place machines (chip shooters can place up to 30 parts PER SECOND and look a lot like a Gatling gun) and Power Looms, achieving also 30 picks or weft insertions per second.And this one going twice as fast as the previous one (2015rpm or 33 per second), but not as detailed:It's insane. But it makes sense. They are essentially encoding near raw materials (yarn on spools and canisters of components) into very detailed designs at an incredibly fast and efficient rate, with very large economic driving functions. Power looms have been getting better for over 200 years, and chip shooters for decades. They're near physical limits for single components at a time. The only things faster are things that operate using a one or two dimensional array, like photolithography (PCBs, computer chips) and printing.
If there are humans on the production line, changing the speed involves intense politics because you are probably torturing some of them. Hence eliminating all human touches first makes a lot of difference.
Quote from: LucR on 05/14/2017 12:59 amQuote from: Daniels30 on 05/13/2017 11:34 pmMerlin 1D uses a method called “Phase shut off”, removes most valves reducing chances of failure by removing components and removing a lot of risk of a hard start.I think he means "face shutoff", meaning propellants are "shut off" at the injector face.See e.g. http://www.rocket-propulsion.info/resources/articles/TRW_PINTLE_ENGINE.pdf.The interesting bit...QuoteAnd, uh, I’ve seen that hurt us before, I’ve seen that fail, but I’ve also seen— where nobody thought it would work— it was the right decision. It was the harder way to do it, but in the end, it was the right thing. One of the things that we did with the Merlin 1D was; he kept complaining— I talked earlier about how expensive the engine was. <inaudible> [I said,] “[the] only way is to get rid of all these valves. Because that’s what’s really driving the complexity and cost.” And how can you do that? And I said, “Well, on smaller engines, we’d go phase-shutoff, but nobody’s done it on a really large engine. It’ll be really different.” And he said, “We need to do phase-shutoff. Explain how that works?” So I drew it up, did some, you know, sketches, and said “here’s what we’d do,” and he* said “That’s what we need to do.” And I advised him against it; I said it’s going to be too hard to do, and it’s not going to save that much. But he made the decision that we were going to do phase-shutoff.So we went and developed that engine; and it was hard. We blew up a lot of hardware. And we tried probably tried a hundred different combinations to make it work; but we made it work. * love the speed of that trade
I don't think any of them worked on a 90 second cycle, except perhaps the guy that drives it off the line. (How does he get back to drive the next one out ?!)
Quote from: oldAtlas_Eguy on 05/14/2017 07:31 pmThe comments from Mueller gives the impression that the M1D has hit all three items instead of just 2 in the cost, performance, reliability tradeoff. This is in itself very significant and also important for SpaceX. They have a very low cost engine with high performance and high reliability. Something that no one else in the US industry has even come close to. Which is why the Atlas V uses the low cost, high performance, high reliability RD-180 from Russia, the only other engine in use in the US that hits all three points.This goal of hitting all three for the Raptor is also encouraging. Using lessons learned and piling the difficulty into development to be able to make such an engine instead of compromising on operational costs to keep development costs down. Musk has it right. If your going to fly lots of them and want to lower operational costs have good or high performance and high reliability, don't push off doing the right things in development for reducing the development costs.I think hitting all three is the baseline standard...
Musk convinced Mueller of using this method despite Mueller explaining what it is and how it increases complexity of R&D and increased costs due to blowing lots of hardware up before mastering the method.
Quote from: AncientU on 05/14/2017 08:47 pmQuote from: oldAtlas_Eguy on 05/14/2017 07:31 pmThe comments from Mueller gives the impression that the M1D has hit all three items instead of just 2 in the cost, performance, reliability tradeoff. This is in itself very significant and also important for SpaceX. They have a very low cost engine with high performance and high reliability. Something that no one else in the US industry has even come close to. Which is why the Atlas V uses the low cost, high performance, high reliability RD-180 from Russia, the only other engine in use in the US that hits all three points.This goal of hitting all three for the Raptor is also encouraging. Using lessons learned and piling the difficulty into development to be able to make such an engine instead of compromising on operational costs to keep development costs down. Musk has it right. If your going to fly lots of them and want to lower operational costs have good or high performance and high reliability, don't push off doing the right things in development for reducing the development costs.I think hitting all three is the baseline standard...What? The conventional approach is "cost, performance, reliability: pick two". Hitting all 3 is rare indeed. Also, while the marginal cost per engine may be low, you have to amortize the development cost, and I get the impression the quoted low cost doesn't take that into account. This quote suggests development cost will have been high: QuoteMusk convinced Mueller of using this method despite Mueller explaining what it is and how it increases complexity of R&D and increased costs due to blowing lots of hardware up before mastering the method.
Re: "I've seen that hurt us before, I've seen that fail".Would it be churlish to imagine a conversation starting along the lines of: "What's the problem with immersing carbon fibre in liquid oxygen, where's the ignition source going to come from?".
Quote from: Hobbes-22 on 05/15/2017 02:08 pmQuote from: AncientU on 05/14/2017 08:47 pmQuote from: oldAtlas_Eguy on 05/14/2017 07:31 pmThe comments from Mueller gives the impression that the M1D has hit all three items instead of just 2 in the cost, performance, reliability tradeoff. This is in itself very significant and also important for SpaceX. They have a very low cost engine with high performance and high reliability. Something that no one else in the US industry has even come close to. Which is why the Atlas V uses the low cost, high performance, high reliability RD-180 from Russia, the only other engine in use in the US that hits all three points.This goal of hitting all three for the Raptor is also encouraging. Using lessons learned and piling the difficulty into development to be able to make such an engine instead of compromising on operational costs to keep development costs down. Musk has it right. If your going to fly lots of them and want to lower operational costs have good or high performance and high reliability, don't push off doing the right things in development for reducing the development costs.I think hitting all three is the baseline standard...What? The conventional approach is "cost, performance, reliability: pick two". Hitting all 3 is rare indeed. Also, while the marginal cost per engine may be low, you have to amortize the development cost, and I get the impression the quoted low cost doesn't take that into account. This quote suggests development cost will have been high: QuoteMusk convinced Mueller of using this method despite Mueller explaining what it is and how it increases complexity of R&D and increased costs due to blowing lots of hardware up before mastering the method.Cost of R&D per engine is related to number of engines manufactured. If the number was going to be only a few hundred then yes but the number of engines produced will be in the thousands. They have flown about 300 M!D already. By end of year they have flown another 150. Next year another 250. Then 300 Then 350. By EOY 2020 if all goes well they will have flown 1350 engines. $1B R&Dcost (It didn't cost that much or even close) is $.75M/engine. Development cost of $500M is $.37M/engine. If the extra cost is $200M over the normal development $500M vs $300M then the increase in cost per engine due to R&D is $.15M. But the decrease in cost per engine due to using the lower parts count is probably a lot more than that.
Quote from: LucR on 05/14/2017 12:59 amQuote from: Daniels30 on 05/13/2017 11:34 pmMerlin 1D uses a method called “Phase shut off”, removes most valves reducing chances of failure by removing components and removing a lot of risk of a hard start.I think he means "face shutoff", meaning propellants are "shut off" at the injector face.See e.g. http://www.rocket-propulsion.info/resources/articles/TRW_PINTLE_ENGINE.pdf.So SpaceX went from an injector plate, with separate propellant injection orifices to a single injector "sprinkler"? Please corret me if wrong but that seems like a major redesign of the engine.
Cost of R&D per engine is related to number of engines manufactured. If the number was going to be only a few hundred then yes but the number of engines produced will be in the thousands. They have flown about 300 M!D already. By end of year they have flown another 150. Next year another 250. Then 300 Then 350. By EOY 2020 if all goes well they will have flown 1350 engines. $1B R&Dcost (It didn't cost that much or even close) is $.75M/engine. Development cost of $500M is $.37M/engine. If the extra cost is $200M over the normal development $500M vs $300M then the increase in cost per engine due to R&D is $.15M. But the decrease in cost per engine due to using the lower parts count is probably a lot more than that.
Quote from: oldAtlas_Eguy on 05/15/2017 02:36 pmCost of R&D per engine is related to number of engines manufactured. If the number was going to be only a few hundred then yes but the number of engines produced will be in the thousands. They have flown about 300 M!D already. By end of year they have flown another 150. Next year another 250. Then 300 Then 350. By EOY 2020 if all goes well they will have flown 1350 engines. $1B R&Dcost (It didn't cost that much or even close) is $.75M/engine. Development cost of $500M is $.37M/engine. If the extra cost is $200M over the normal development $500M vs $300M then the increase in cost per engine due to R&D is $.15M. But the decrease in cost per engine due to using the lower parts count is probably a lot more than that.That sounds more like number of flights than number of engines built. If they've built 3-400 engines with a lot of reflights, that makes the R&D more expensive than production costs. Cheers, Martin
SpaceX's New Mini-Falcon 9, the Block 5, Will Re-Fly in a Day - Inversehttps://apple.news/AVU1upgaoQXK_bQSG9C-8Yg
If they've built 3-400 engines with a lot of reflights, that makes the R&D more expensive than production costs.
Q: Have any other production engines done "face shutoff"?
Mueller also criticizes the excessive price of NASA’s currently under construction Space Launch System, which is going to cost billions of dollars but not be reusable.“If your rocket costs a billion dollars, even if you use it 100 times, it’s still going to be very expensive to use. So we set out to build low-cost rockets from the very beginning.”
With regards to the mixture ratio range of 3.6 - 3.8. A mixture ratio of 3.6 has ~10% excess fuel where as 3.8 has ~5%. Where it ends up will depend on combustion efficiency trends. It is easier to get high combustion efficiency with a larger excess of fuel, harder with lower excess, and really hard at stoichiometric. They may even allow for tuning between these mixture ratios for different uses. For example, the Mars burn will favor ISP over density*ISP, which the booster will favor.
This is ridiculous reading between the lines. One of those political hits from the competitors. I don't see that it has anything to do with SLS.QuoteMueller also criticizes the excessive price of NASA’s currently under construction Space Launch System, which is going to cost billions of dollars but not be reusable.“If your rocket costs a billion dollars, even if you use it 100 times, it’s still going to be very expensive to use. So we set out to build low-cost rockets from the very beginning.”Source http://www.inquisitr.com/4219361/spacex-employee-ridicules-completion-from-europe-ula-and-russia-but-spares-blue-origin/
Didn't F1-3 fail because of all the fuel between the valve and the injector bleeding out after the valve closed, which would have been prevented by FSO?
What other rocket costs a billion dollars?
Quote from: ArbitraryConstant on 05/15/2017 05:04 pmWhat other rocket costs a billion dollars?ITS. Musk said it would cost 10 billion to develop.
Quote from: king1999 on 05/15/2017 04:47 pmThis is ridiculous reading between the lines. One of those political hits from the competitors. I don't see that it has anything to do with SLS.QuoteMueller also criticizes the excessive price of NASA’s currently under construction Space Launch System, which is going to cost billions of dollars but not be reusable.“If your rocket costs a billion dollars, even if you use it 100 times, it’s still going to be very expensive to use. So we set out to build low-cost rockets from the very beginning.”Source http://www.inquisitr.com/4219361/spacex-employee-ridicules-completion-from-europe-ula-and-russia-but-spares-blue-origin/What other rocket costs a billion dollars?
Science reporting gone wrong:QuoteSpaceX's New Mini-Falcon 9, the Block 5, Will Re-Fly in a Day - Inversehttps://apple.news/AVU1upgaoQXK_bQSG9C-8YgThis interview is now hitting more press sites, but this article gets almost every detail wrong. A Merlin burning methane and a mini F9 with a single one of them? FH is the big brother rocket headed to Mars? Wow, there's wrong, dead wrong and then there's this.
Quote from: rockets4life97 on 05/15/2017 05:07 pmQuote from: ArbitraryConstant on 05/15/2017 05:04 pmWhat other rocket costs a billion dollars?ITS. Musk said it would cost 10 billion to develop.Talking about unit cost for a launch, not cost to develop.
Yes, many. Small engines, nothing on the scale of Merlin IIRC. To lower costs and increase reliability.Not a problem with them, because to change the design isn't so difficult, so you get a rapid ROI by doing so.
Does it reduce any weight?
...* 800 lbs is 340-385 kg.
Quote from: Space Ghost 1962 on 05/15/2017 09:48 pmAneutronic fusion has a much higher Coulumb barrier.There's also Bremsstrahlung losses, which AIUI is an even bigger problem. The energy comes out as kinetic energy in charged nuclei from each fusion. Because they're charged they emit x-rays as they interact with the rest of the plasma, and the plasma is optically thin to x-rays. This makes it hard to reach Q=1 (breakeven), especially with magnetic confinement.
Aneutronic fusion has a much higher Coulumb barrier.
One other thing that was interesting which mueller mentioned which fits into NSF spacex constellation thread...He was talking about 70% of your webbrowser is accessed via cache... which made me wonder... is one of the reasons the spx satellites is so big (400-100kg from memory) is that they're including massive cache-end storage systems? (similiar to what google/akamai/etc already co-locate in a large #s of isps)I have zero knowledge about the power/mass requirements of satellites for a given coverage area but I thought this was insightful as to their intentions. Searched the threads for speculation from more informed folks but nada as yet. Apologize if I missed it.
As to power/volume/other, look to SSD technology to get the basics on the amount one could fit in. Likely a few terabytes per each.
One benefit of being a LEO constellation is that like the ISS, one is under the inner Van Allen belts unlike geosats, so radiation isn't as much a consideration.
Quote from: Hobbes-22 on 05/15/2017 02:08 pmQuote from: AncientU on 05/14/2017 08:47 pmQuote from: oldAtlas_Eguy on 05/14/2017 07:31 pmThe comments from Mueller gives the impression that the M1D has hit all three items instead of just 2 in the cost, performance, reliability tradeoff. This is in itself very significant and also important for SpaceX. They have a very low cost engine with high performance and high reliability. Something that no one else in the US industry has even come close to. Which is why the Atlas V uses the low cost, high performance, high reliability RD-180 from Russia, the only other engine in use in the US that hits all three points.This goal of hitting all three for the Raptor is also encouraging. Using lessons learned and piling the difficulty into development to be able to make such an engine instead of compromising on operational costs to keep development costs down. Musk has it right. If your going to fly lots of them and want to lower operational costs have good or high performance and high reliability, don't push off doing the right things in development for reducing the development costs.I think hitting all three is the baseline standard...What? The conventional approach is "cost, performance, reliability: pick two". Hitting all 3 is rare indeed. Also, while the marginal cost per engine may be low, you have to amortize the development cost, and I get the impression the quoted low cost doesn't take that into account. This quote suggests development cost will have been high: QuoteMusk convinced Mueller of using this method despite Mueller explaining what it is and how it increases complexity of R&D and increased costs due to blowing lots of hardware up before mastering the method.What is conventional about EM's approach to problem solving?Falcon design effort didn't settle for two, nor did Tesla... path chosen reduces to a value judgement of the person driving a development program. Those that are driven by a committee usually settle for much less.Hitting all three is only rare because most designers/manufacturers/committees don't try.Note: The cliche is "Faster, Better, Cheaper -- pick two"
the vast and electron-thirsty computer-server farms that make up the backbone of what we call “the cloud.” In his report, Mills estimates that the ICT system now uses 1,500 terawatt-hours of power per year. That’s about 10% of the world’s total electricity generation
Tom Mueller specifically talked about the backbone. That is the communication between the data storage centers, not the storage it self.
"So why the heck does it cost some fraction of a million dollars to build a Merlin engine?"Uh... it costs less than a million dollars? That's pretty amazing. That means the recovered stage 1 must be worth less than something like $10m.
Quote from: IainMcClatchie on 05/16/2017 03:38 am"So why the heck does it cost some fraction of a million dollars to build a Merlin engine?"Uh... it costs less than a million dollars? That's pretty amazing. That means the recovered stage 1 must be worth less than something like $10m.There is a lot more cost in a stage than just the marginal cost to produce the engines.
Quote from: AncientU on 05/15/2017 05:15 pmQuote from: Hobbes-22 on 05/15/2017 02:08 pmQuote from: AncientU on 05/14/2017 08:47 pmQuote from: oldAtlas_Eguy on 05/14/2017 07:31 pmThe comments from Mueller gives the impression that the M1D has hit all three items instead of just 2 in the cost, performance, reliability tradeoff. This is in itself very significant and also important for SpaceX. They have a very low cost engine with high performance and high reliability. Something that no one else in the US industry has even come close to. Which is why the Atlas V uses the low cost, high performance, high reliability RD-180 from Russia, the only other engine in use in the US that hits all three points.This goal of hitting all three for the Raptor is also encouraging. Using lessons learned and piling the difficulty into development to be able to make such an engine instead of compromising on operational costs to keep development costs down. Musk has it right. If your going to fly lots of them and want to lower operational costs have good or high performance and high reliability, don't push off doing the right things in development for reducing the development costs.I think hitting all three is the baseline standard...What? The conventional approach is "cost, performance, reliability: pick two". Hitting all 3 is rare indeed. Also, while the marginal cost per engine may be low, you have to amortize the development cost, and I get the impression the quoted low cost doesn't take that into account. This quote suggests development cost will have been high: QuoteMusk convinced Mueller of using this method despite Mueller explaining what it is and how it increases complexity of R&D and increased costs due to blowing lots of hardware up before mastering the method.What is conventional about EM's approach to problem solving?Falcon design effort didn't settle for two, nor did Tesla... path chosen reduces to a value judgement of the person driving a development program. Those that are driven by a committee usually settle for much less.Hitting all three is only rare because most designers/manufacturers/committees don't try.Note: The cliche is "Faster, Better, Cheaper -- pick two"People don't try because hitting all 3 is generally seen as impossible. And it remains to be seen if SpaceX has done it. If they had to invest $1B to drive the marginal cost down to $30k, it'll take years for that savings to pay off. SpaceX and Tesla aren't infallible, Tesla is finding out they're missing the "reliability" part of the triangle with the Model X, and Falcon 9 reliability is not above average for the industry.
Impossible (to some definition) in the first round/deadline. Once you have two out of three, you can start working to get the third. Takes longer, meanwhile you have product up and working. Cost reduction is very common place in the mobile handset business for example, once the product has been out for a while. Seems to be the approach taken by SpaceX. Got it working, now working on getting it cheaper.
Nothing has been said yet about data cache as a function of the constellation. Could be a potential new line of business for serving the ConnX and similar networks, since there is ... a great heat sink.
Huh? Vacuum is an amazing insulator.
Quote from: AncientU on 05/16/2017 12:26 pmNothing has been said yet about data cache as a function of the constellation. Could be a potential new line of business for serving the ConnX and similar networks, since there is ... a great heat sink. Huh? Vacuum is an amazing insulator. Multi-megawatt data centers on the ground can use the oceans and the atmosphere as a heat sink, using evaporative cooling, dumping heat directly into cold sea water, or other techniques. Compared with the heat exchangers you can use on the ground, you'll need much larger radiators in orbit to sink megawatts into vacuum.
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The amount of storage and power needed to cache movies and video is fairly minor. 10 TB of storage should do it.
The latency for SpaceX satellites will be low. No need for server farms in orbit. It's a terrible environment for data storage and pretty hard for the hardware techs to access. Without being able to swap out failed components, capacity will rapidly drop. Just keep data storage on the ground.
(The first hard drive I ever maintained was 14MB and the size of a dishwasher) Used on a system with core memory)
I believe he said marginal cost for a Model S. That means, given their existing physical plant, etc, what is the cost for Tesla to make a Model S vs not making one. That should be much lower than the sale price, as it only includes marginal labor, materials, and maybe wear and tear on production equipment.
Too much specific that belongs on the SpaceX a sat vendor topic for this thread.Although I find it interesting much of this has been discussed in great detail on that other thread as much as a year ago.
What part of not talking about fusion on this thread were we having trouble with? thanks.
Quote from: RonM on 05/16/2017 08:44 pmThe latency for SpaceX satellites will be low. No need for server farms in orbit. It's a terrible environment for data storage and pretty hard for the hardware techs to access. Without being able to swap out failed components, capacity will rapidly drop. Just keep data storage on the ground.Also key to caching is locality. You cache Bollywood movies in India, but not in Siberia. And vice-versa, whatever that may be.Cache nearby, and use the constellation for distribution, since "nearby" in practical terms can still be thousands of miles.
Yeah, the idea that you could build a gas generator cycle rocket for less than $10M was once unbelievable. Any day now someone will produce one in their garage, although electric pumps have essentially taken that scale in a different direction.
Quote from: Space Ghost 1962 on 05/16/2017 03:24 amOne benefit of being a LEO constellation is that like the ISS, one is under the inner Van Allen belts unlike geosats, so radiation isn't as much a consideration.Isn't the constellation going to be just in the lower reaches of the belt at 1100 km?
>Am also not sure how high SX LEO communication sat constellation might really be. They might intentionally have the first ones low, intending them to be short lived, knowing that a second generation would be on the heels of the first.
Quote from: Nomadd on 05/16/2017 10:07 pm (The first hard drive I ever maintained was 14MB and the size of a dishwasher) Used on a system with core memory)Good old Memorex 660...
Quote from: rpapo on 05/16/2017 10:34 pmQuote from: Nomadd on 05/16/2017 10:07 pm (The first hard drive I ever maintained was 14MB and the size of a dishwasher) Used on a system with core memory)Good old Memorex 660...Back in 1976 the hard drive on the computer in the Pychoacoustic Lab at SUNY Binghamton was either 5 or 10 MB. Not really the good old days.
Quote from: DOCinCT on 05/17/2017 07:34 pmQuote from: rpapo on 05/16/2017 10:34 pmQuote from: Nomadd on 05/16/2017 10:07 pm (The first hard drive I ever maintained was 14MB and the size of a dishwasher) Used on a system with core memory)Good old Memorex 660...Back in 1976 the hard drive on the computer in the Pychoacoustic Lab at SUNY Binghamton was either 5 or 10 MB. Not really the good old days.Likely an DEC PDP-11 RK-05 "pizza platter". Often had "head crashes". add:I bought my first disk drive for a start-up company I was doing. It was an ATASI 40MB 5.25" hard drive with a ST-506 interface to a Western Digital WD-1002 controller. About $5,000.
Quote from: QuantumG on 05/16/2017 03:53 amYeah, the idea that you could build a gas generator cycle rocket for less than $10M was once unbelievable. Any day now someone will produce one in their garage, although electric pumps have essentially taken that scale in a different direction.I once saw a comment that rl10 (not a GG, of course), could be built for about the same as a helicopter engine ($40k?) after a lot of re-engineering.
Wonder how many of these development decisions TM discusses like face-shutoff and their associated challenges/costs are included in the $1B investment in reusable rockets SpaceX now advertises. Could be most everything past Falcon 9 v1.0 with M1-Cs. Lots of benefits have accrued to the company before considering reusability, so they could be 'double-booking' these development costs. $1B always seemed high to me...
Quote from: AncientU on 05/17/2017 11:21 pmWonder how many of these development decisions TM discusses like face-shutoff and their associated challenges/costs are included in the $1B investment in reusable rockets SpaceX now advertises. Could be most everything past Falcon 9 v1.0 with M1-Cs. Lots of benefits have accrued to the company before considering reusability, so they could be 'double-booking' these development costs. $1B always seemed high to me...I would bet it is included. Any kind of reusability with propulsive landing scheme is extremely reliant on a reliable engine that *will* start... And to my knowledge, the M1D has never failed a restart in flight. (The M1DVac did once, but has since operated flawlessly as far as we know)
The insistence on reusability “drives the engineers insane,” says Vozoff. “We could’ve had Falcon 1 in orbit two years earlier than we did if Elon had just given up on first stage reusability. The qualification for the Merlin engine was far outside of what was necessary, unless you plan to recover it and reuse it. And so the engineers are frustrated because this isn’t the quickest means to the end. But Elon has this bigger picture in mind. And he forces them to do what’s hard. And I admire that about him.”
48 minute mark: "We want to exploration first before we do colonization."
Quote from: QuantumG on 05/19/2017 01:01 am48 minute mark: "We want to exploration first before we do colonization."Sure, that are the RedDragon missions.
Quote from: guckyfan on 05/19/2017 05:55 amQuote from: QuantumG on 05/19/2017 01:01 am48 minute mark: "We want to exploration first before we do colonization."Sure, that are the RedDragon missions.There's going to be more exploration than that. The first few ITS landings will be for small exploration outposts at first... They are not going to start colonization with the first flights.
Quote from: Lars-J on 05/19/2017 05:58 amQuote from: guckyfan on 05/19/2017 05:55 amQuote from: QuantumG on 05/19/2017 01:01 am48 minute mark: "We want to exploration first before we do colonization."Sure, that are the RedDragon missions.There's going to be more exploration than that. The first few ITS landings will be for small exploration outposts at first... They are not going to start colonization with the first flights.In my understanding they do. It will be a permanent base with the clear intention to expand it into a settlement. Sure they will look into the surrounding area. Probably supported by NASA who will send their scientist astronauts.
by going face-shutoff, we got rid of the main valves
In the interview, Tom Mueller said:Quoteby going face-shutoff, we got rid of the main valvesMakes sense, but then why does the launch sequence still talk about pre-chilling the engines? If there are no main values, then I'd think that as soon as they loaded the tank, the fuel/LOX would flow down through the engine until it encountered the shutoff at the injector face. So the engine would already be chilled, just sitting there.Perhaps they are pre-chilling the gas generator, which *is* on the other side of some valves? Perhaps there is another valve (but not a "main" valve) in the way? Anyone have any idea?
First constellation table in image. LEO & VLEO technical PDF's attached.
Quote from: docmordrid on 05/17/2017 07:07 pmFirst constellation table in image. LEO & VLEO technical PDF's attached.Hm... Edmonton is 53.5 N, which is the northernmost major city in NA.
Quote from: guckyfan on 05/19/2017 06:11 amQuote from: Lars-J on 05/19/2017 05:58 amQuote from: guckyfan on 05/19/2017 05:55 amQuote from: QuantumG on 05/19/2017 01:01 am48 minute mark: "We want to exploration first before we do colonization."Sure, that are the RedDragon missions.There's going to be more exploration than that. The first few ITS landings will be for small exploration outposts at first... They are not going to start colonization with the first flights.In my understanding they do. It will be a permanent base with the clear intention to expand it into a settlement. Sure they will look into the surrounding area. Probably supported by NASA who will send their scientist astronauts.Then we are arguing semantics about what 'colonization' means. An exploration outpost is not a colony in my mind, but I realize that there will be a fuzzy transition period if that outpost eventually becomes a starting point for a colonization effort.
Quote from: LouScheffer on 05/19/2017 02:24 pmIn the interview, Tom Mueller said:Quoteby going face-shutoff, we got rid of the main valvesMakes sense, but then why does the launch sequence still talk about pre-chilling the engines? If there are no main values, then I'd think that as soon as they loaded the tank, the fuel/LOX would flow down through the engine until it encountered the shutoff at the injector face. So the engine would already be chilled, just sitting there.I bet they don't want any of their LOX boiling into gas as it "just sits there" in the lines.
In the interview, Tom Mueller said:Quoteby going face-shutoff, we got rid of the main valvesMakes sense, but then why does the launch sequence still talk about pre-chilling the engines? If there are no main values, then I'd think that as soon as they loaded the tank, the fuel/LOX would flow down through the engine until it encountered the shutoff at the injector face. So the engine would already be chilled, just sitting there.
There have to be valves on the inlets to the turbine or they'd never be able to shut off or throttle the engine. LOX sitting in the engine doesn't necessarily cool the turbine and the turbopumps.
This LOX is going to be boiling during prelaunch. All those bubbles are going up. If the LOX plumbing has any high spots, there's going to be a big gas bubble in those spots. As anyone who's turned on a faucet after partially draining and then repressurizing their house plumbing knows, when that gas bubble gets to the injector face the mass flow rate is going to rapidly vary by way over an order of manitude. Sounds like a hard start to me.
If I recall correctly there's sometimes a surprisingly largish fireball blown out of the flame trench at start-up that's probably caused by a large pool of cold GOX accumulating from the chill venting. Don't remember which launches/hotfires it was, But somebody did notice it a couple of times.
Quote from: Chris_Pi on 05/23/2017 06:31 amIf I recall correctly there's sometimes a surprisingly largish fireball blown out of the flame trench at start-up that's probably caused by a large pool of cold GOX accumulating from the chill venting. Don't remember which launches/hotfires it was, But somebody did notice it a couple of times.Maybe you could reduce the startup fireball effect by spraying liquid nitrogen into the flame trench just before Falcon 9 ignition.
