Yes, in the landing phase. One of those non-intuitive discoveries that you only find out by doing (or try doing) the way the text books say.
My point was that refueling doesn't "enable" landing on the Moon, and perhaps Mars. It "enhances" those landings with larger payloads and/or the ability to return. For a one-way landing of small cargo (for values of "small" that include things much larger than anyone can currently land on the Moon), a single launch is sufficient.I don't think it's likely to happen, but if someone wanted to pay, just for example, $500 million to land 5 tonnes on the Moon, BFR/BFS could do it in a single launch with no refueling.
Things is if your big pitch is "much lower cost through full reusability" the flip side is much higher cost as you're going to throw away a whole vehicle designed for the economics of reuse. It'd be like flying the Shuttle as an uncrewed drone with no crew on board and minimal consumables. Possible but a massive amount of money to deliver a fairly small increase in payload.
For vehicles like F9S1, which have to take account of unpredicted winds and land on seagoing platforms.Otherwise, this is not clear.
Expect a far more stripped down version of BFR/S initially. Bare minimal features for a ship to deliver a commercial satellite to orbit and return to earth with all stages reused. ...
...I think it's fair to say that the BFS flying rolling out in 2019 or 20 will be a very minimal vehicle and a long way from the final Mars capable BFR.
Things is if your big pitch is "much lower cost through full reusability" the flip side is much higher cost as you're going to throw away a whole vehicle designed for the economics of reuse.
And I’m gonna guess they’ll be working out the bugs using the moon as a target (I know a very different EDL profile, but between moon and earth EDLs they’ll have covered a lot of development territory) and you don’t have to wait for several years between attempts...
Quote from: john smith 19 on 03/19/2018 08:45 pm...I think it's fair to say that the BFS flying rolling out in 2019 or 20 will be a very minimal vehicle and a long way from the final Mars capable BFR. ...a very minimal Nova-class vehicle.
What comforts me about the whole credo and philosophy of SpaceX is that the company is absolutely wedded to science- and engineering-based planning as well as First Principles-thinking. Whatever they are suggesting, no matter how outlandish it initially seems, it will be based on sound science and engineering. If First Principles indicate the way to go, SpaceX will take it.I find their initial planning much more convincing than the hodgepodge that is NASA. The Shuttle was a weird compromise conditioned by budgetary constraints, divvying out contracts based on regionalism and politics, military requirements, Cold War posturing, and many similar unscientific considerations. The NASA strategy post-Shuttle... Well, I don't think we need to waste time on that mess.SpaceX is, on the contrary, driven by a clear vision, centrally formulated, and with no regard for peripheral interests. They display great flexibility combined with a single-minded focus on a clear, visionary mission.I agree with others that their iterative approach is a true strength. They can start out with a bare-bones model of the BFS and develop it incrementally, adding features. I think the first "BFS" we will see will be a boilerplate outer-mold line mega-Grashopper, perhaps powered by a couple of scavenged Merlins and Falcon tankage + plumbing, doing increasingly large hops on the Texas coast.
Quote from: envy887 on 03/19/2018 08:08 pmMy point was that refueling doesn't "enable" landing on the Moon, and perhaps Mars. It "enhances" those landings with larger payloads and/or the ability to return. For a one-way landing of small cargo (for values of "small" that include things much larger than anyone can currently land on the Moon), a single launch is sufficient.I don't think it's likely to happen, but if someone wanted to pay, just for example, $500 million to land 5 tonnes on the Moon, BFR/BFS could do it in a single launch with no refueling.Things is if your big pitch is "much lower cost through full reusability" the flip side is much higher cost as you're going to throw away a whole vehicle designed for the economics of reuse. It'd be like flying the Shuttle as an uncrewed drone with no crew on board and minimal consumables. Possible but a massive amount of money to deliver a fairly small increase in payload.
Don't get hopes up for much 'hanging out'... they'll learn all they need from trips back and forth to Moon and Mars.
Quote from: Oersted on 03/20/2018 01:40 pmWhat comforts me about the whole credo and philosophy of SpaceX is that the company is absolutely wedded to science- and engineering-based planning as well as First Principles-thinking. Whatever they are suggesting, no matter how outlandish it initially seems, it will be based on sound science and engineering. If First Principles indicate the way to go, SpaceX will take it.I find their initial planning much more convincing than the hodgepodge that is NASA. The Shuttle was a weird compromise conditioned by budgetary constraints, divvying out contracts based on regionalism and politics, military requirements, Cold War posturing, and many similar unscientific considerations. The NASA strategy post-Shuttle... Well, I don't think we need to waste time on that mess.SpaceX is, on the contrary, driven by a clear vision, centrally formulated, and with no regard for peripheral interests. They display great flexibility combined with a single-minded focus on a clear, visionary mission.I agree with others that their iterative approach is a true strength. They can start out with a bare-bones model of the BFS and develop it incrementally, adding features. I think the first "BFS" we will see will be a boilerplate outer-mold line mega-Grashopper, perhaps powered by a couple of scavenged Merlins and Falcon tankage + plumbing, doing increasingly large hops on the Texas coast.Agreed until the last sentence. No need, much wasted effort and little gained by flying Merlins on the BFS boilerplate/prototype. Raptor has been in development for many years. Prototypes test fired since 2016. Given the AF contract milestones calling for methane engine program completion next month, it would surprise, no SHOCK me if the very first BFS whatchmacallit test vehicle did not use Raptors of some scale from day one.The major tech challenge for BFR is the robustness of the composite tanks and structure.Mitigated by going back to the heavier aluminum tech used today and simply sacrificing payload tonnage to LEO.IF re-useable TPS proves to be an unresolvable issue in the early years, refurbish time and costs get added on per next flights.So the answer to the topic question posed is this. Every new technical risk has a work around that lets the program continue with limitations on performance (tonnage to LEO, times of re-use, etc.) and/or increase in cost per flight. Even with these limitations, the end result would be a major advance.