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Falcon 9 Delivers Dragon Into Orbit, Flubs Landing
Jeff Findley wrote on Fri, 7 Dec 2018
07:17:04 -0500: In article , says... Niklas Holsti wrote on Thu, 6 Dec 2018 19:01:58 +0200: On 18-12-06 13:06 , Jeff Findley wrote: Also, the stage managed to land very well on the ocean (as can be seen in a video posted by an observer on social media). SpaceX also released the on board camera footage from the stage which showed that once the landing burn started, the engines were able to negate the roll caused by the stuck grid fin. I thought the landing uses only one engine, therefore probably the center engine -- then how can the engine control roll? I don't understand. The same way any other single engine booster controls roll, I would think. The engine gimbals. That would be a neat trick. Or not. On Falcon 1, that version of Merlin had a gimbal on the turbo-pump exhaust for roll control. As far as I know, they deleted that feature on Merlins used for Falcon 9 since the extra complexity wasn't needed anymore. Wiki indicates that the ability to gimbal was removed as of the Merlin 1C engine. Everything else I find, including the Payload User's Guide, indicates that the Merlin 1D engines on a Falcon 9 do indeed still have the ability to gimbal and gimballing is used to control pitch, yaw, and roll for the first stage. -- "Now I'm hiding in Honduras. I'm a desperate man. Send lawyers, guns and money. The **** has hit the fan." -- "Send Lawyers, Guns, and Money", Warren Zevon |
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Falcon 9 Delivers Dragon Into Orbit, Flubs Landing
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Falcon 9 Delivers Dragon Into Orbit, Flubs Landing
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Falcon 9 Delivers Dragon Into Orbit, Flubs Landing
"Jeff Findley" wrote in message
... So, even if SpaceX wants to reuse first stages, sometimes the customer simply won't allow it (hint: GPS III satellites cost a hell of a lot more to make than a Falcon 9 first stage). Jeff As an aside, a friend of mine has been working on this project (on the GPS III sat). I'm not 100% sure of her role, but she's been quite frustrated that the delays ruined her planned Christmas week off, but she's quite happy to see it on orbit now! -- Greg D. Moore http://greenmountainsoftware.wordpress.com/ CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net IT Disaster Response - https://www.amazon.com/Disaster-Resp...dp/1484221834/ |
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Falcon 9 Delivers Dragon Into Orbit, Flubs Landing
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Falcon 9 Delivers Dragon Into Orbit, Flubs Landing
JF Mezei wrote on Fri, 28 Dec 2018
20:13:31 -0500: On 2018-12-28 08:57, Jeff Findley wrote: I'm sure the delays were frustrating everyone, but this was the first "critical" DOD flight on a Falcon 9, so best to get it right. I have to wonder how "critical" this really was for DoD. Certaintly not a secret launch, and not secret hardware or orbit. I can see that it is important to get the first of a new constellation up to test it. It was 'critical' enough that they elected to fly it on a Falcon 9 rather than wait to get the originally planned Delta IV launcher. BTW, in terms of not landing the stages. Was this on a leftover Block4 or a new Block5 ? It was a Block 5. I was told the goal was to stop poduction of Falcon9 in order to focus on BFR/BFS. If they get too many request for expendanbvle Falcon9, won't they have to review their manufacturing plan for Falcon9? I'm sure things are under constant review based on current demand. This shouldn't be a surprise to anyone. -- "Some people get lost in thought because it's such unfamiliar territory." --G. Behn |
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Falcon 9 Delivers Dragon Into Orbit, Flubs Landing
In article ,
says... On 2018-12-28 08:57, Jeff Findley wrote: I'm sure the delays were frustrating everyone, but this was the first "critical" DOD flight on a Falcon 9, so best to get it right. I have to wonder how "critical" this really was for DoD. Certaintly not a secret launch, and not secret hardware or orbit. SpaceX close out 2018 with GPS III launch written by Chris Gebhardt December 23, 2018 https://www.nasaspaceflight.com/2018...gps-iii-first- national-security-mission/ From above: first US. National Security mission and Launch of the GPS III-SV01 spacecraft marked SpaceX's first competitively awarded EELV, Evolved Expendable Launch Vehicle, contract with the US. Air Force and is the first of the new generation of GPS III satellites to launch. Prior DOD launches on Falcon 9 were not considered "National Security" launches, from every article I've read. GPS III is considered to be critical for US forces, unlike prior DOD launches on Falcon 9. I can see that it is important to get the first of a new constellation up to test it. The Air Force wanted to reserve as much propellant as possible to insure the success of the primary mission. They dictated no landing attempt, so no grid fins or landing legs on this mission. BTW, in terms of not landing the stages. Was this on a leftover Block4 or a new Block5 ? I was told the goal was to stop poduction of Falcon9 in order to focus on BFR/BFS. If they get too many request for expendanbvle Falcon9, won't they have to review their manufacturing plan for Falcon9? New Block 5. All flights going forward will be Block 5. Also, Falcon production lines are obviously not shut down as the "hopper" prototype for Starship hasn't even flown once yet. So no, I doubt this impacts their manufacturing plan one iota. The plan, especially for the US Air Force, is to keep flying Falcon as long as there is demand. If a customer is paying, there will be a Falcon to launch. No sane company stops selling the previous model abruptly. There is always a transition period, often of many years. They just keep jacking up the price of the previous model (that they really don't want to support) until the customers switch to the new model. Without giving away the details, the company I work for still builds and ships an "old product" even though its "replacement product" (actually a rebranding of another product) started sales in 2002. Note that this was way back when Windows XP was still relatively "new". In the "old product", there aren't any new features added or bugs fixed, we just build it, test it, and ship it. Even when Starship starts flying, Falcon will be no different, IMHO. DOD/US Air Force especially will no doubt want to stick with the "proven" launch vehicle for several years. Jeff -- All opinions posted by me on Usenet News are mine, and mine alone. These posts do not reflect the opinions of my family, friends, employer, or any organization that I am a member of. |
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Falcon 9 Delivers Dragon Into Orbit, Flubs Landing
JF Mezei wrote on Sat, 29 Dec 2018
13:01:49 -0500: On 2018-12-29 08:23, Jeff Findley wrote: Prior DOD launches on Falcon 9 were not considered "National Security" launches, from every article I've read. GPS III is considered to be critical for US forces, unlike prior DOD launches on Falcon 9. I have to wonder what the "critical" designation is. Adding 1 satellite to existing GPS constellation simply complements an existing service. There is a lot more to GPS than you're aware of. But it is critical in that being the first of new generation, they want to test/evaluate it likely before launching the rest. No. It is 'critical' because it is a Block III bird. The Air Force wanted to reserve as much propellant as possible to insure the success of the primary mission. They dictated no landing attempt, so no grid fins or landing legs on this mission. From an actual performance point of view, would legs and fins make a noticeable dent in performance? (akaL is the dead weight worth the cost or removing them ? Since this was a new build, it is a no brainer to simply not install them during assembly, but had this been a re-used block 5, would SpaceX have bothered removing them? Since they're easily removed and designed for that, why wouldn't you? Also, Falcon production lines are obviously not shut down as the "hopper" prototype for Starship hasn't even flown once yet. So no, I doubt this impacts their manufacturing plan one iota. OK, so so far, all that has changed was the end of development for Falcon9 ? I had read here that there were plans to sut down production of Falcon9 now that block 5 could be re-used many times. You're like a two-year-old. Everything is RIGHT NOW. What you've read here is that there are plans to reduce and eventually shut down Falcon 9 production. This hasn't really changed. Once a sufficiently large stock of Falcon 9 exists I'd still expect them to shut down that production line. If DoD becomes a major customer and insists on wasting perfectly good stages, won't that force SpaceX to change its plans and continue to produce them for much longer than originally anticipated? I would currently anticipate that BFR/BFS will be ready around 2024-25. Add another 5-10 years for them to become 'routine' and demonstrated reliable. I take it that the floor/building space and tooling for Falcon9 construction isn't going to be needed for BFR/BFS and that the two can proceed at the same time ? The biggest bottleneck is skilled workers. Also, while it is mentioned that this "had" to be expendable due to performance, is that really really the case? Reading that article, especially the section about lawsuits, I get the feeling that someone wanted the SpaceX flights to be more expensive so as to not make the ULA costs look so absurd. Your 'feelings' are not evidence. This launch was to an excessively high inclination, so they still had to do a large plane change. I seriously doubt ULA costs had anything to do with it beyond Congress telling USAF that they need to get cheaper launches. GPS satellites are about halfway to geosync and not at equatotial inclination, so no need to "undo" the latitude you are launching from. Or are those satellites much heavier than what is normnally launched to geosync ? A plane change is a plane change. They had to make a large plane change to get this bird on orbit. No sane company stops selling the previous model abruptly. What I had been told here was that Musk planned to shut production of new block 5s and just keep re-using the ones that were built. Yes, ONCE THERE IS A SUFFICIENTLY LARGE EXISTING INVENTORY. Doh! BTW, once BFR is running, if the Falcon9 is truly at its performance limit for GPS satellites, won't it become cheaper to launch on BFR which will have pklenty fo spare performance to return and be re-used, thuse lowering price ? Once it has demonstrated reliability it will be cheaper to launch EVERYTHING on BFR/BFS because of the order of magnitude increase in reusability. -- "Some people get lost in thought because it's such unfamiliar territory." --G. Behn |
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Falcon 9 Delivers Dragon Into Orbit, Flubs Landing
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