It would be interesting, if it was one of the two other engines, which had to perform the retroboost.Does anyone have an idea how much work is required to replace an engine?If they have plenty of them due to reuse of rocketstages, they could replace damaged engines and refurbish them seperately.
Quote from: meekGee on 01/12/2016 12:31 amQuote from: Kabloona on 01/12/2016 12:27 amQuote from: meekGee on 01/11/2016 09:55 pmWell if the engines are ~$1.5M, and if the Atlas slide is correct, than the F9 does not cost $60M. So something's gotta give.It's an Atlas slide. Why would you assume F9 has identical cost breakdowns? It's a completely different vehicle.Because apart from the engines, it's a similar structure, similar fuel, similar size... It can't be THAT different. If the Merlins are 1.5 Million, then the engine stack is 15M. So the structures would have to be some 30M to get the entire rocket to 60M. That's very far from the Atlas breakdown... 2:1 instead of 1:2....Yes, it can be very different. For one simple example that jumps out from the chart, I expect the cost of avionics is very different, and seems to be a good chunk of ULA's costs, by the pie chart shown. ULA uses typical radiation resistant aerospace components and systems; SpaceX uses pretty COTS components for its systems and software, getting reliability by redundancy in the systems (many CPU's, etc), running much more modern software. Given the cost of those modern components (which are far faster than anything you can get "radiation hardened"), I don't understand how to spend the kind of money that ULA current has to spend, despite having to have that redundancy; modern semiconductor technology and Moore's law being what it has been. SpaceX gave a talk at a Linux conference a few years ago describing (to the extent that the export control laws allow) what they were doing in their systems.Sometimes, by revisiting systems from scratch, you can get to a very different (better) point that following the path of "incremental improvement". Clean sheets can be a real advantage; but you don't get them very often. SpaceX did a "clean sheet" on most everything.So don't presume the actual costs in the different rockets are "the same", unless you are comparing fundamental costs (e.g. propellants, or N kilograms of aluminum alloy)... And one of Musk's strengths is that he thinks terms of those fundamental costs, rather than what people have traditionally paid....
Quote from: Kabloona on 01/12/2016 12:27 amQuote from: meekGee on 01/11/2016 09:55 pmWell if the engines are ~$1.5M, and if the Atlas slide is correct, than the F9 does not cost $60M. So something's gotta give.It's an Atlas slide. Why would you assume F9 has identical cost breakdowns? It's a completely different vehicle.Because apart from the engines, it's a similar structure, similar fuel, similar size... It can't be THAT different. If the Merlins are 1.5 Million, then the engine stack is 15M. So the structures would have to be some 30M to get the entire rocket to 60M. That's very far from the Atlas breakdown... 2:1 instead of 1:2....
Quote from: meekGee on 01/11/2016 09:55 pmWell if the engines are ~$1.5M, and if the Atlas slide is correct, than the F9 does not cost $60M. So something's gotta give.It's an Atlas slide. Why would you assume F9 has identical cost breakdowns? It's a completely different vehicle.
Well if the engines are ~$1.5M, and if the Atlas slide is correct, than the F9 does not cost $60M. So something's gotta give.
Since the first stage doesn't go into space, does ULA, SpaceX or any other company bother to use rad-hardened electronics on the first stage? If so, then why?
Then how does a Falcon 9 first stage do RTLS without avionics?Spacex doesn't use rad hard electronics for any of their avionics, it's all off the shelf technology with error check/correction and voting redundancies handling the errors.
(you can also see the double TEA-TEB flash on this mission too)
Quote from: Dante80 on 01/16/2016 11:10 am(you can also see the double TEA-TEB flash on this mission too)My guess: it's a single TEA-TEB firing which is obscured by the very bright RP-1 burning before the engines get to full thrust.
So if debris is coming into the engines, is that likely then happening during the descent through the atmosphere?
Quote from: CuddlyRocket on 01/13/2016 11:53 pmThey may have to, but I imagine the first thing they'll try is additional redundancy. But I agree that someone within SpaceX will be working this, though I suspect the FH will be throwing stuff to Mars well within 10 years.Quite likely but I think they'll be a rad level where every processor is in the process of reboot so none is processing any workload.
They may have to, but I imagine the first thing they'll try is additional redundancy. But I agree that someone within SpaceX will be working this, though I suspect the FH will be throwing stuff to Mars well within 10 years.
Shielding would be another option, say a chunk of plastic (high H atom density)...
This image appears to show, at the base of the engine bells, what looks like a stitched material (curved, divided into relatively small squares by what looks like the stitching, darker black than most of surrounding image)? Can that be true? Either way, what is it and what are its likely eventual failure modes?
Quote from: inonepiece on 01/07/2016 08:59 pmThis image appears to show, at the base of the engine bells, what looks like a stitched material (curved, divided into relatively small squares by what looks like the stitching, darker black than most of surrounding image)? Can that be true? Either way, what is it and what are its likely eventual failure modes?The engines are wrapped in a bullet proof shroud intended to prevent cascading failures in the event that an engine has a catastrophic failure. This is what you see, I'm sure it also fulfills all the other uses mentioned earlier in the thread.
Quote from: pippin on 01/04/2016 03:37 amRight now a significant number of their payloads need to use the margin they have for landing the stage so it can't be reused.Shotwell has cited the main benefit of the F9FT is allowing a barge landing on flights that wouldn't have been able to in the past (GTO). It has yet to be established just how heavy a payload the F9FT can throw to GTO and still carry legs and reserve propellant for a downrange landing. A barge landing is estimated to require a ~15% performance margin. I am guessing we won't really know for sure immediately as the next GTO payload (SES-9) is quite heavy.According to Wiki the heaviest bird F9 has thrown to GTO was TurkmenAlem52E/MonacoSAT: https://en.wikipedia.org/wiki/TurkmenAlem52E/MonacoSAT at 4707kg. According to Gunter's, SES-9 is 5330kg, so it will be the heaviest payload to GTO for F9 to date.I threw together a quick table of upcoming flights and masses to get an idea of how many recovery flights might be possible over the next year or so. I didn't spend a ton of time vetting these so some flights might have been delayed/canceled/whatever. Masses are from Gunter's and I note when I am estimating based on a similar bird. I categorized payload recovery as Yes, Probably, Possibly, and Unlikely based on mass and past history, and taking into account the ~33% payload increase to GTO that F9FT is supposed to provide.Payload Mass Dest Recovery Possible?~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~Jason-3 533kg LEO YesCRS-8 ?kg LEO YesCRS-9 ?kg LEO YesSES-9 5330kg GTO Possibly (based on evidence that a barge landing will be attempted)SES-10 5300kg GTO PossiblyThaicom 8 3100kg GTO YesABS 2A, Eutelsat 117 West B ~4000kg? GTO Possibly (based on ABS-3A, Eutelsat 115 West B mass)JCSAT-14 ~3400kg? GTO Probably (based on JCSAT-15 mass)BulgariaSat-1 ~3400kg? GTO Probably (based on JCSAT-15 mass, same SSL-1300 bus)JCSAT-16 ~3400kg? GTO Probably (based on JCSAT-15 mass)KoreaSat-5 4465kg GTO PossiblyEs'hail-2 ~3000kg GTO ProbablyCRS-11 ?kg LEO YesCRS-12 ?kg LEO YesFormosat-5 525kg SSO YesIridium NEXT 1 ~8000kg? LEO Yes (800kg x 9 + estimated adapter mass)Iridium NEXT 2 ~8000kg? LEO Yes (800kg x 9 + estimated adapter mass)Iridium NEXT 3 ~8000kg? LEO Yes (800kg x 9 + estimated adapter mass)Iridium NEXT 4 ~8000kg? LEO Yes (800kg x 9 + estimated adapter mass)Iridium NEXT 5 ~8000kg? LEO Yes (800kg x 9 + estimated adapter mass)Based on this I count 15 likely recovery flights out of 20. That's a far cry from "only a few flights" being possible for recovery. And that's arguably conservative, as F9FT should have enough margin to recover anything that has previously flown on an F91.1 (up to 4707kg).Corrections welcome, I am sure there is some stuff that will likely need to be fixed here.Update: I've updated SES-9 and 10 to "possibly" based on news that an application for barge landing has been filed. That means that, theoretically, all of the upcoming launches will allow for recovery.
Right now a significant number of their payloads need to use the margin they have for landing the stage so it can't be reused.
Quote from: watermod on 01/16/2016 04:02 pmSince the first stage doesn't go into space, does ULA, SpaceX or any other company bother to use rad-hardened electronics on the first stage? If so, then why?2. Unlike almost all other space companies, SpaceX does not use radiation hardened electronics - instead they go for "radiation tolerant". Rad hardened electronics mean chips with a structure size that was state of the art in the 1980's. That means their performance is sub par by roughly 30 years and they are also extremely expensive and in some cases very hard to get to.
Quote from: CorvusCorax on 01/17/2016 04:15 pmQuote from: watermod on 01/16/2016 04:02 pmSince the first stage doesn't go into space, does ULA, SpaceX or any other company bother to use rad-hardened electronics on the first stage? If so, then why?2. Unlike almost all other space companies, SpaceX does not use radiation hardened electronics - instead they go for "radiation tolerant". Rad hardened electronics mean chips with a structure size that was state of the art in the 1980's. That means their performance is sub par by roughly 30 years and they are also extremely expensive and in some cases very hard to get to.I'd say that 15 to 20 years is more accurate.By the way, it is possible to use more recent mainstream semiconductor process technology to build relativelyradiation hardened processors and ASICs using specific techniques in circuit design, logic design, and layout.This is done in mission critical computers (mainframes and high end Unix servers) where the goal is to makethe chance of an undetected error under normal terrestrial background radiation extremely close to zero overthe operating life of the machine (a decade or more).The problem is the market volumes for rad hard are so small it is hard to justify the extra design effort (whichwould also makes the devices somewhat larger, slower, and more power hungry than straight commercialproducts) or going the usual way, the expense of keeping a true rad hard process in production and portingover an obsolete commercial processor design under license.