Sorry if I missed this, but which of these is SpaceX building/testing first?
2020/1 BFS hopper is constructed with no TPS to work on landing and initial airframe assurance, followed by the first BFS Second flight of BFS after a month, then once a week for a couple of months, then once a day for a month.2021 with the first BFS, after some test flights, SpaceX offers the ability for any relatively small sat to be launched to LEO, nearly any day you want, with the ability to check it out in orbit for a short period before release, and if not, land. (this would be before deployment). Starlink launches begin.2022, Starlink launches accelerate as BFR comes online, in time to launch several BFS to Mars in September.A rapid ramp of BFR cadence finishes the full Starlink constellation rather sooner than expected.The first crewed launches occur.
BFR is planned to fly hundreds of people, both to low Earth orbit, our ultimate destination is Mars, but that system is being designed also to do Earth hops. And those are some of the first tests that you’ll actually see with the Falcon spaceship.
Will be starting with a full-scale Ship doing short hops of a few hundred kilometers altitude and lateral distance. Those are fairly easy on the vehicle, as no heat shield is needed, we can have a large amount of reserve propellant and don't need the high area ratio, deep space Raptor engines.Next step will be doing orbital velocity Ship flights, which will need all of the above. Worth noting that BFS is capable of reaching orbit by itself with low payload, but having the BF Booster increases payload by more than an order of magnitude. Earth is the wrong planet for single stage to orbit. No problemo on Mars.
Quote from: maitri982 on 01/01/2018 01:08 amSorry if I missed this, but which of these is SpaceX building/testing first?There has been no absolutely unambiguous announcement.Arguments can be made for both - BFR is 'simpler', being 'just a scaled up F9', BFS is smaller, and allows testing of some components before developing BFR.In order to get to Mars in 2022, you need to launch Sep 2022, with 2 BFS, at least 1 BFR, and at least one other BFS or tanker - as an absolute minimum.Statements were made by Gwynne Shottwell at the national space council that they'd test suborbital hops first, which I take to mean that they'll be testing BFS first, in the context they were made.Everything else depends on funding, and how development goes.In the other thread, my optimistic prediction was:Quote2020/1 BFS hopper is constructed with no TPS to work on landing and initial airframe assurance, followed by the first BFS Second flight of BFS after a month, then once a week for a couple of months, then once a day for a month.2021 with the first BFS, after some test flights, SpaceX offers the ability for any relatively small sat to be launched to LEO, nearly any day you want, with the ability to check it out in orbit for a short period before release, and if not, land. (this would be before deployment). Starlink launches begin.2022, Starlink launches accelerate as BFR comes online, in time to launch several BFS to Mars in September.A rapid ramp of BFR cadence finishes the full Starlink constellation rather sooner than expected.The first crewed launches occur.On to musings more important than mine.Gwynne Shotwell testifying (speaking?) before the national space council saidQuote BFR is planned to fly hundreds of people, both to low Earth orbit, our ultimate destination is Mars, but that system is being designed also to do Earth hops. And those are some of the first tests that you’ll actually see with the Falcon spaceship. Her words seem entirely consistent with ship testing first.In the context of the question, about passenger transport, it might even imply that it can do significant passenger service-capable hops.From Elon - from reddit QuoteWill be starting with a full-scale Ship doing short hops of a few hundred kilometers altitude and lateral distance. Those are fairly easy on the vehicle, as no heat shield is needed, we can have a large amount of reserve propellant and don't need the high area ratio, deep space Raptor engines.Next step will be doing orbital velocity Ship flights, which will need all of the above. Worth noting that BFS is capable of reaching orbit by itself with low payload, but having the BF Booster increases payload by more than an order of magnitude. Earth is the wrong planet for single stage to orbit. No problemo on Mars. (bold mine).This implies to me that the payload for BFS-SSTO is >>1.5 tons, and <15 tons, or he would have said 'two orders of magnitude'.If he in fact meant it can do this and land, which is somewhat plausible with the right assumptions, or that this was a theoretical capacity which would therefore never happen before BFR development is again arguable. The first opens many interesting possibilities.
1. Gwynne and Elon have both hinted that the ship will be developed first. And according to Elon it can reach orbit by itself with a small payload.
Quote from: FutureMartian97 on 01/01/2018 02:01 am1. Gwynne and Elon have both hinted that the ship will be developed first. And according to Elon it can reach orbit by itself with a small payload. No, Elon has not said that for sure BFS can reach orbit with a small payload.He has said something along the line that it might reach some orbit with a small payload.And that orbit might not be a usable orbit for any commercial/institutional payload.
It seems reasonable to note here that the upper stages of the Saturn 5 were developed first. There were reasons for this, some of which might be common to the BFR/BFS development. One commonality is that the upper stages of the Apollo moon rocket were capable of reaching orbit without the first stage booster.A second commonality is that the Apollo capsule and service module were more challenging (longer time) to develop than the booster as is the BFS more challenging than the BFR.
So,Elon has stated that BFS will fly/be tested first before BFRElon's schedule chart in his IAC presentations shows BFS first.There should be no question at this time that BFS flies first, pending future contradicting statements or events.Why BFS first?1. BFS has more new, unproven tech, e.g. BOTH types of Raptor engines, TPS, flight path, etc. so de-risk the program before the rest is set in stone.2. BFS can start test flights with only the 3 sea level Raptors, thereby proving the full thrust Raptor engines and getting Raptor ECO design modifications into the factory before scads of Raptors get built and need to be modified at expense.3. BFS also allows Rvac testing, not available on BFR.4. BFS with its legs can be used serendipitously to pre-qualify the landing software at a precision needed for BFR cradle landings.5. Likely Musk & his Musketeer engineering staff have additional good reasons for BFS first.I think the first BFR test flights will fly with less than 31 engines but that is only an opinion, likely to be wrong.
The big thing for BFR is the launch cradle.
I think the Big Falcon Rocket (BFR) will be tested first before the Big Falcon Spaceship (BFS).Don't why, but it's my personal opinion. You don't have to agree if you think differently.
Quote from: Robotbeat on 01/02/2018 12:46 pmThe big thing for BFR is the launch cradle.I don't think cradle landing is strictly required. If it can't be made to work, SpaceX can fall back to landing legs. This would make relaunch a little bit more expensive, but I don't think it would be a show stopper.
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.
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.
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.
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.
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.
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.
Quote from: JamesH65 on 01/03/2018 06:12 pmPrototypes launched, some failures, not yet ready to take over from F9/H. So what kind of failures do you see happening?
if we get lucky, be able to do short hop flights with the spaceship part of BFR maybe next year. By hopper tests I mean kind-of-like the grasshopper program for falcon 9, where we just had the rocket take take off and land in Texas at our Texas test site so we'd either do that at our South Texas launch site, near Brownsville or or do ship-to-ship. We're not sure yet whether ship-to-ship or Brownsville, but most likely it's gonna happen in our Brownsville location because got a lot of land with nobody around and so if it blows up, it's cool.By hopper test I mean it'll go up several miles then come down. The ship is capable of single stage to orbit if you fully load the tanks. So we'll do flights of increasing complexity. We really want to test the heatshield material so, like you know fly out turn around accelerate back real hard and come in hot to test the heat shield, because we want to have a highly reusable heat shield that's capable of absorbing heat from interplanetary entry velocities. So it's really tricky.The ship part is by far the hardest because that's going to come in from super-orbital velocities. Mars transfer velocities these are way harder than coming in from low-earth orbit. There's some of the heating things that scale to the eighth power. I diddn't think there's anything that scales to eight power but turns out on reentry certain elements of reentry heating scale to the 8th so just testing that ship out is the real tricky part.The booster I think we understand reasonable boosters. Reusable spaceships that can land propulsively that's that's harder, so we're starting with the hard part first.I think it's conceivable that we do our first full-up orbital test flight in 3-4 years including the booster. inaudible question on moon/mars We'd go to low earth orbit first but it would be capable of going to the moon very shortly thereafter it's designed to do that.
