Quote from: Robotbeat on 01/02/2018 12:46 pmThe big thing for BFR is the launch cradle.Yes.By contrast, for BFS, they would just need some flat concrete to launch and land it, someplace where they'll allow it, and somewhere near an ocean port, something like Landing Zone 1.
The big thing for BFR is the launch cradle.
Quote from: Patchouli on 01/02/2018 04:23 pmThe cradle not working out would not be a deal killer in fact I think it's kinda a bad idea as it increases the risk of a mishap destroying the launch facilities.A botched landing of BFR with a separate landing site you only loose the vehicle but a botch landing with the cradle you damage the launch facilities.Inclined to agree. SpaceX /could/ design a level of resilience for a shared launch+landing mount. Perhaps a modular cradle, ready to be swapped out in the event of an unexpectedly crunchy landing. But still, if a tipsy booster bumps the tower then your launch campaign is well and screwed.Returning to a dedicated landing pad risks so much less, and costs... well, what? 1) a means of transport back to the launch pad, 2) a second booster, for optimal launch cadence. It seems likely SpaceX will already have both of those.And a separate landing pad does not necessitate the addition of legs to the booster. It's just another cradle, located safely apart from the tower and GSE. Win-win.
The cradle not working out would not be a deal killer in fact I think it's kinda a bad idea as it increases the risk of a mishap destroying the launch facilities.A botched landing of BFR with a separate landing site you only loose the vehicle but a botch landing with the cradle you damage the launch facilities.
I'm expecting the first BFR to have legs, as grasshopper did, until they get its landing accuracy good enough. Seems like a big ask to get the whole cradle thing working right from the initial prototype stage.
Hmm maybe too much cost to bother. But could a BFS be put up into orbit under it's own power and then a FH send up landing propellent? Im thinking cost of developing the tank might make it a non starter but throwing it out there.
Alot of people here seem to have trouble with the basic concept of BFR/BFS. It is much cheaper to fly this huge rocket then to fly ANYTHING else. They will not use falcon/falcon heavy to support BFS. Doing so would cost millions of dollars more then using another BFR/BFS for support.
Alot of people here seem to have trouble with the basic concept of BFR/BFS. It is much cheaper to fly this huge rocket then to fly ANYTHING else. They will not use falcon/falcon heavy to support BFS. Doing so would cost millions of dollars more then using another BFR/BFS for support. Every Falcon launch still throws millions of dollars of hardware into the ocean. Second stage, interstage and fairings are all lost. BFR loses nothing! Everything is recovered! No lost hardware! Dumping money into falcon or heavy is just wasted.Spacex is moving on from Falcon. Just accept that fact.Steve
Quote from: Steve D on 01/03/2018 04:18 pmAlot of people here seem to have trouble with the basic concept of BFR/BFS. It is much cheaper to fly this huge rocket then to fly ANYTHING else. They will not use falcon/falcon heavy to support BFS. Doing so would cost millions of dollars more then using another BFR/BFS for support. Every Falcon launch still throws millions of dollars of hardware into the ocean. Second stage, interstage and fairings are all lost. BFR loses nothing! Everything is recovered! No lost hardware! Dumping money into falcon or heavy is just wasted.Spacex is moving on from Falcon. Just accept that fact.SteveReally? I not seeing that in the conversation above. AFAICT, most people here are fully versed in the proposed cheapness of the BFR/BFS combination compared with Falcon.However, what I also see is huge optimism that the BFx combination will be fully working and operational within a 5 year timescale. That is a very short amount of time to develop something like this.
They will not use falcon/falcon heavy to support BFS. Doing so would cost millions of dollars more then using another BFR/BFS for support. Every Falcon launch still throws millions of dollars of hardware into the ocean.
Second stage, interstage and fairings are all lost.
So where do you think they'll be in development in 5 years?
Prototypes launched, some failures, not yet ready to take over from F9/H.
<snip - of F9H-refuelling>So only the second stage is lost.
Minor question, instead of BFS for the spacecraft and BFR for the booster, why not use orbiter for the former and booster for the latter? That way it distinguishes the booster from the overall system, BFR.
The rocket that they are working on is referred to internally by the code name BFR. And it doesn't stand for some arcane, smarty-pants science term. It stands for Big frakking Rocket.I ask Musk whether he really calls it that; his answer is both delightfully nerdy, and not."Well, there's two parts of it—there's a booster rocket and there's a spaceship... So, technically, it would be the BFR and the BFS." As in "Big frakking Spaceship."
And then the ship, which is the hardest part, just by far the hardest part of the vehicle, of the BFR system, or interplanetary transport system. Because the ship has to have a heatshield that's capable of re-entering from very high velocities. From velocities way higher than... Basically interplanetary velocities, as opposed to orbital velocities. It's got to control itself through a wide regime, from everything from vacuum, to rarefied gas. Everything from thin atmosphere to thick atmosphere. Hypersonic, supersonic, transonic, subsonic. Different types of atmosphere, from different planets. And then land on unimproved terrain, and be able to take off from unimproved terrain. That's a pretty ridiculous set of requirements for the ship. That's why we're focusing on the ship first, because it's kind of the hard part.
So our focus is on the ship, and we expect to hopefully do short flights on the ship, with the ship next year. You know, aspirational.
Personally I see BFR landing on the launch pad as the weakest link. This landing concept is the one thing I would remove from the architecture and return to the proven F9 concept.Even if you achieve a 95% perfect landing rate (to be demonstrated) then you are going to destroy or severely damage the pad one out 20 launches, the required launch rate would make this a real risk considering they have one pad usable for this.This is why BFR should be first, to retire this risk.