Quote from: TrueBlueWitt on 07/26/2021 06:09 pmQuote from: LouScheffer on 07/26/2021 05:26 pmQuote from: Jim on 07/26/2021 03:18 pmQuote from: Paul451 on 07/26/2021 02:21 pmAre there any larger variants of the Star motor that were manufactured in the current century, are flight rated and not unflown research projects, and thus could reasonably be considered to be "available" to NASA for the EC mission without them having to fund NG to restart a development program that was shut down a generation ago?Pegasus motors (Orion 50s) were looked at. They may have been looked at, but ORION motors can be discarded as a possibility for direct-to-Jupiter pretty easily. From the catalog, ORION 50S XLT (high performance, air start) masses 16221 kg at start, and 1121 kg at burnout. Assuming an isp of 294 (IUS like) that's a delta V with a 6000 kg payload of 3279 m/s. So for a final C3 of 80, you need the booster to give a C3 of -2.4 to a 22.2 ton payload. But FH can only boost 16 tonnes to this C3 (LSP plot only goes to C3 = -1.7, but that's a very minor extrapolation). So it's not even close.You also need a new(heavier) payload adapter for over 10,000 Kg.Elon has said many times the easiest way to boost FH performance is to stretch the S2. He said they hadn't done it due to no previous missions needing it. Is this the one?Can you close the gap doing this? How much of a stretch would it require?For non-expendable FH and F9 this would also have a positive "knock-on" performance effect reducing S1 burnout velocity/apogee reducing residual prop required.I wondered that as I’ve seen a few people state that this mission will be flying with a stretched S2.
Quote from: LouScheffer on 07/26/2021 05:26 pmQuote from: Jim on 07/26/2021 03:18 pmQuote from: Paul451 on 07/26/2021 02:21 pmAre there any larger variants of the Star motor that were manufactured in the current century, are flight rated and not unflown research projects, and thus could reasonably be considered to be "available" to NASA for the EC mission without them having to fund NG to restart a development program that was shut down a generation ago?Pegasus motors (Orion 50s) were looked at. They may have been looked at, but ORION motors can be discarded as a possibility for direct-to-Jupiter pretty easily. From the catalog, ORION 50S XLT (high performance, air start) masses 16221 kg at start, and 1121 kg at burnout. Assuming an isp of 294 (IUS like) that's a delta V with a 6000 kg payload of 3279 m/s. So for a final C3 of 80, you need the booster to give a C3 of -2.4 to a 22.2 ton payload. But FH can only boost 16 tonnes to this C3 (LSP plot only goes to C3 = -1.7, but that's a very minor extrapolation). So it's not even close.You also need a new(heavier) payload adapter for over 10,000 Kg.Elon has said many times the easiest way to boost FH performance is to stretch the S2. He said they hadn't done it due to no previous missions needing it. Is this the one?Can you close the gap doing this? How much of a stretch would it require?For non-expendable FH and F9 this would also have a positive "knock-on" performance effect reducing S1 burnout velocity/apogee reducing residual prop required.
Quote from: Jim on 07/26/2021 03:18 pmQuote from: Paul451 on 07/26/2021 02:21 pmAre there any larger variants of the Star motor that were manufactured in the current century, are flight rated and not unflown research projects, and thus could reasonably be considered to be "available" to NASA for the EC mission without them having to fund NG to restart a development program that was shut down a generation ago?Pegasus motors (Orion 50s) were looked at. They may have been looked at, but ORION motors can be discarded as a possibility for direct-to-Jupiter pretty easily. From the catalog, ORION 50S XLT (high performance, air start) masses 16221 kg at start, and 1121 kg at burnout. Assuming an isp of 294 (IUS like) that's a delta V with a 6000 kg payload of 3279 m/s. So for a final C3 of 80, you need the booster to give a C3 of -2.4 to a 22.2 ton payload. But FH can only boost 16 tonnes to this C3 (LSP plot only goes to C3 = -1.7, but that's a very minor extrapolation). So it's not even close.
Quote from: Paul451 on 07/26/2021 02:21 pmAre there any larger variants of the Star motor that were manufactured in the current century, are flight rated and not unflown research projects, and thus could reasonably be considered to be "available" to NASA for the EC mission without them having to fund NG to restart a development program that was shut down a generation ago?Pegasus motors (Orion 50s) were looked at.
Are there any larger variants of the Star motor that were manufactured in the current century, are flight rated and not unflown research projects, and thus could reasonably be considered to be "available" to NASA for the EC mission without them having to fund NG to restart a development program that was shut down a generation ago?
A stretched S2 would be a new launch vehicle configuration.
Quote from: LouScheffer on 07/26/2021 05:26 pmThey may have been looked at, but ORION motors can be discarded as a possibility for direct-to-Jupiter pretty easily.It never was for direct-to-Jupiter. There was only one option for that.And staged solids was looked at.
They may have been looked at, but ORION motors can be discarded as a possibility for direct-to-Jupiter pretty easily.
Details of the FH extended fairing.https://twitter.com/spacex360/status/1429380060373524486?s=19
Are there any non-military payloads that would require that one?
Quote from: alugobi on 08/22/2021 06:42 pmAre there any non-military payloads that would require that one?The launch of PPE+HALO (the two first parts of Lunar Gateway) needs the extended fairing. It was ordered back in February, and launch is tentatively planned for 2024.
Quote from: tbellman on 08/22/2021 06:55 pmQuote from: alugobi on 08/22/2021 06:42 pmAre there any non-military payloads that would require that one?The launch of PPE+HALO (the two first parts of Lunar Gateway) needs the extended fairing. It was ordered back in February, and launch is tentatively planned for 2024.Do we know where the extended fairing is produced? Is it in Hawthorn or did they contract it out?
Quote from: yoram on 08/22/2021 06:57 pmQuote from: tbellman on 08/22/2021 06:55 pmQuote from: alugobi on 08/22/2021 06:42 pmAre there any non-military payloads that would require that one?The launch of PPE+HALO (the two first parts of Lunar Gateway) needs the extended fairing. It was ordered back in February, and launch is tentatively planned for 2024.Do we know where the extended fairing is produced? Is it in Hawthorn or did they contract it out?There was news about SpaceX simply buying the fairing from RUAG who also make them for ULA and others, but I don't have any confirmed source for what they actually went for. >
ULA claimed IP rights.https://www.reddit.com/r/spacex/comments/cpyq97/comment/ewul0ow/
Quote from: docmordrid on 08/22/2021 10:12 pmULA claimed IP rights.https://www.reddit.com/r/spacex/comments/cpyq97/comment/ewul0ow/ULA claimed IP rights to the fairing they had RUAG develop for them. Other companies can still get RUAG to design and build a fairing.
did they contract it out?
Quote from: yoram on 08/22/2021 06:57 pm did they contract it out?They didn't
...snip...There are three give-aways that the long fairing will be produced by SpaceX in-house:- shape of the fairing at the bottom is identical to that of the standard fairing (same tooling)- Curvature ratio of the top section of the fairing is identical to that of the standard fairing (same tooling)- The "dents" in the payload envelope in the curved section are the same (both size and location) for standard and long fairings. Those "dents" house the pneumatic separation pushers. So, same design feature for standard and long fairings.The only major difference between both fairings is how the seam between the fairing halves is separated. Pneumatic mechanical latches on standard fairing. Bolted frangible seam on long fairing. Those are direct indications for NO recovery and NO reuse of long fairings. Which in turn tells us that SpaceX expects the long fairings to be rarely used and thus those fairings will be expendable. The long fairing will likely be used on just a handful of specific NSS missions and one-off missions such as the PPE-HALO launch. Thus, not worth the effort to recover them intact and reuse them.EDIT: Jim just confirmed that the long fairing is indeed a SpaceX in-house product. See post immediately below.
I've read somewhere that Starlink is volume limited, not mass limited, so this might be able to help there also.
[I fail to see how a major reliability feature would be abandoned.
How are the seam separation features different? Source? I didn't see any different features in the User's Guide. As I recall, the mechanical latches were a big SpaceX differentiator , as frangible bolts can't be tested. I fail to see how a major reliability feature would be abandoned. ...
The two halves of the standard fairing are fastened by mechanical latches along the fairing vertical seam. To deploy the fairing, a high-pressure helium circuit releases the latches, and four pneumatic pushers facilitate positive-force deployment of the two halves. The use of all-pneumatic separation systems provides a benign shock environment, allows acceptance and preflight testing of the actual separation system hardware, and minimizes debris created during separation.The two halves of the extended fairing are fastened by a bolted frangible seam joint. To deploy the fairing, redundant detonators initiate a detonation cord contained inside an expanding tube assembly. The detonation causes the expanding tube to expand outwards and break the structural seam between the two fairings in a controlled and contained manner. Four pneumatic pushers facilitate positive-force deployment of the two halves. The use of a nonbolted clamshell interface between the payload fairing and the rest of the vehicle provides significant shock attenuation of the separation event, maintaining environments for the payload well within nominal payload requirements.
Quote from: markbike528cbx on 10/04/2021 06:40 pm[I fail to see how a major reliability feature would be abandoned. Mass. The standard fairing and its latches is very heavy compared to other equivalents.Also, other than the Taurus fairing issues, what other fairings had reliability uses?
