Quote from: Jim on 06/18/2010 02:26 pmQuote from: mlorrey on 06/18/2010 05:16 amGiven the stuff they've had to deal with on the FTS I'd buy that part of the increased cost is due to the interface with government bureaucracies, but also that they haven't yet demonstrated reusability of any part of their vehicles.There is a biased opinionA. The FTS was all Spacex's fault. They made a bad assumption and tried flying without an FTS. Hence their work on an FTS got a late start.B. The cost increases go way back.I think that SpaceX was somewhat justified in their assumption not to use FTS, despite the fact that it should have been discussed fully with the range prior to making that decision.Reason I say this is simply looking forward to a time where we have reusable rocket planes carrying people to and from orbit on a daily basis - they are not going to carry FTS systems. If SpaceX used Falcon 9 tech as a basis of a rocketplane designed to carry people - would they still be required to fly an FTS?I think SpaceX were thinking they could usher in this world but didn't consider the fact that their rocket in it's present form is actually no different than all of the others launching from the range!
Quote from: mlorrey on 06/18/2010 05:16 amGiven the stuff they've had to deal with on the FTS I'd buy that part of the increased cost is due to the interface with government bureaucracies, but also that they haven't yet demonstrated reusability of any part of their vehicles.There is a biased opinionA. The FTS was all Spacex's fault. They made a bad assumption and tried flying without an FTS. Hence their work on an FTS got a late start.B. The cost increases go way back.
Given the stuff they've had to deal with on the FTS I'd buy that part of the increased cost is due to the interface with government bureaucracies, but also that they haven't yet demonstrated reusability of any part of their vehicles.
Quote from: Nathan on 09/17/2010 10:17 pmReason I say this is simply looking forward to a time where we have reusable rocket planes carrying people to and from orbit on a daily basis - they are not going to carry FTS systems.How do you get a reusable rocket plane to be reliable enough not to need a LAS (and by implication an FTS)?cheers, Martin
Reason I say this is simply looking forward to a time where we have reusable rocket planes carrying people to and from orbit on a daily basis - they are not going to carry FTS systems.
Quote from: MP99 on 09/17/2010 10:29 pmQuote from: Nathan on 09/17/2010 10:17 pmReason I say this is simply looking forward to a time where we have reusable rocket planes carrying people to and from orbit on a daily basis - they are not going to carry FTS systems.How do you get a reusable rocket plane to be reliable enough not to need a LAS (and by implication an FTS)?cheers, MartinHow do yo get a regular airliner safe enough so they don't require every passenger to have a parachute? Lots of testing and flight experience.
I'm confused. Why are we discussing FTS and passengers on this thread? My understanding is that a Super Heavy lift vehicle would be much more effective if it were unmanned, and then have a smaller manned launcher (e.g. F9/Dragon) rendezvous with the Super Heavy payload in LEO. This way, you only pay for man-rating margins on the smaller launcher. In other words, my understanding is that an unmanned SHLV would carry significantly more mass to orbit.Wasn't Ares V supposed to be unmanned for this reason?Am I missing something?
Yes, I know, as soon as they have any sort of second stage recovery, they can get below 1 engine per flight, raising the capacity to LEO to several 100 mt per engine. But as long as they don't have any second stage recovery, there is that optimization-problem.
The business case for a re-usable 3 stick rocket against an expendable one stick (FHR vs F9E) is already much tougher to make than before F9 became a true EELV (as opposed to a Delta II replacement)....Moreover, this is not easy technically to do. Think of the added complexity, as well as the changes needed to the pads, the erectors, the integration facilities, the landing zones, etc etc. .....The best way to actually improve the re-usable/recoverable fraction of the vehicle vs the expendable, would be to work on stage two recovery.....
Why are people so enamored with helicopter capture?
Quote from: Dante80 on 01/10/2016 11:40 amThe business case for a re-usable 3 stick rocket against an expendable one stick (FHR vs F9E) is already much tougher to make than before F9 became a true EELV (as opposed to a Delta II replacement)....Moreover, this is not easy technically to do. Think of the added complexity, as well as the changes needed to the pads, the erectors, the integration facilities, the landing zones, etc etc. .....The best way to actually improve the re-usable/recoverable fraction of the vehicle vs the expendable, would be to work on stage two recovery.....Good points against a Super Heavy.Yes, the evolution of the F9 into it's current class is making the business case for the FH more and more difficult I think. The speculated capability to deliver near 6 tons to GTO is creeping into the sweet spot for revenue generation. SpaceX should probably be trying to figure out how to be more competitive in the remaining payloads coming up for bid in this class, ( 5-7 ton) while still optimizing re-use options. SpaceX does not seem to be in too big a rush or concerned about the schedule lag, as they don't really have ay payloads to launch.While the re-usability is important long term, the current configuration still delivers less than stellar results when all 3 cores are RTLS or barge landed. The penalties are pretty big. The really impressive LEO or beyond numbers are achieved only when the center core gets expended, or when all cores are expended. Currently the FH was stated to get 6.4 tons to GTO when all cores are returned. That is an awful lot of complex rocket sitting on the pad for the slight improvement over a single stick F9 expendable.I think an interesting option would be to consider smaller boosters than that would enhance the margin of the center core, pushing it solidly into +6ton to GTO capacity, while giving the core more margin for barge landing. Smaller boosters vs. the current FH configuration would also give S2 more weight margin, which might make the difference for reusability happening sooner, vs. waiting for a more advanced S2 engine to enable re-use.The idea of a Super Heavy doesn't make any sense for anything that is going to be launched anytime in the next decade or more, and it pretty much a non starter to think of adding more engines and width to an already complex beast. Anything "Super Heavy" from SpaceX will be based on the Raptor engine/BFR plans.It's possibly into off topic territory , but here's my concept for smaller boosters for a "F9 Medium Heavy" that would push well past 6 tons to GTO and give more margin for barge return. I'll argue that what make a rocket a "Super Heavy" is what is actually possible to build and fly. This design might be more "Super" than some of the concepts that started this thread in 2010 with +50 engines in the configuration!2 boosters, powered by 4 Merlin 1D FT engines, reducing engine count vs. current FH by 10. Mass of each booster is around 85,000 kg, and burns out in 95 seconds. The vehicle is past MaxQ when they jettison. These smaller booster should also be able to be re-used. I envision that they completely consume all their fuel, and maneuver with grid fins after separation for a parachute deployment and mid-air snag by land based helicopters. Empty booster weight should be able to be kept under 9000 kg to make this possible. No drone ships or hoverslam for the boosters, but depending on payload, the core still do as it currently does, just more margin. Here's a quick and dirty photo edit of the concept. I basically shrunk the existing side cores by 54% for a representative look at the size. Side booster are now around 30 meters tall, 2 meter core.The "Falcon Medium Heavy"
My version of a FH supper heavy is start with a FHFT add crossfeed and then a Raptor 5m diameter US of same length (ISP 385) of about same weight as the M1DVAC-FT US, which yields if the 1st stage are driven to depletion and US close to depletion:LEO - ~83mtTLI - ~30.4mtTMI- ~23mtNo need to get fancy for a significant amount of extra performance for those really big missions that might occur in next 10 years.
The "Falcon Medium Heavy"
The use of smaller boosters does not make economic sense when reuse is considered. The small cost savings in manufacture is not reflected in much of any savings in refurbishment such that a full size set of boosters is almost the same cost as that of the smaller booster ones. Further decreasing the economies of scale on each of the booster sizes may also in total increase the costs such that no savings whatsoever would be had.