Direct GEO insertion is going to need a few refills, depending on the payload.You need ~4,200m/s to get to GEO from LEO, with the payload, then another ~1800m/s to get back to GTO, from there you can aerobrake.
Cost per launch that SX could see with BFR would be lower than the smaller launchers. So for price per launch they would meet todays market and be ready for tomorrows market at the smaller launcher price, but at a launch mass of the HLV. And that is if their price is $20M per launch ( $8M for hardware and launch + $12M profit , based on last years cost estimate for ITS and about 20% of $62M for F9 launch ). Even if the price were $40M per launch that would be hard to bet, that is if they had half as many flights of reuse per unit made. What if the per launch price was $60M per launch, for smaller payloads they could launch 2 to 4 at a time, that brings the price per payload to $15M each.They might make a small launcher later on, I've suggested this in the past. The BFR is the 747 and the small a corporate jet or 737 to compare.
You also might want to split reentry in two or more passes as well since returning from GTO is going to be similar to a lunar return and a vehicle like this probably would not survive an Apollo style reentry.
Quote from: Patchouli on 10/05/2017 06:41 amYou also might want to split reentry in two or more passes as well since returning from GTO is going to be similar to a lunar return and a vehicle like this probably would not survive an Apollo style reentry.BFS' primary purpose is to go to Mars and return. Reentry from Mars is even higher velocity than from Luna. Aerobraking passes would add time to the return, but yea, I wonder whether they will be necessary.
Quote from: TomH on 10/05/2017 07:19 amQuote from: Patchouli on 10/05/2017 06:41 amYou also might want to split reentry in two or more passes as well since returning from GTO is going to be similar to a lunar return and a vehicle like this probably would not survive an Apollo style reentry.BFS' primary purpose is to go to Mars and return. Reentry from Mars is even higher velocity than from Luna. Aerobraking passes would add time to the return, but yea, I wonder whether they will be necessary.Why should it be more difficult for BFS to shed the velocity? The command module of Apollo had 12 m^2 of heat shield and weighted around 6 mT. Thats 0.5 mT per m^2. The reentry mass of a BFS is about 150 mT (85mT dry, plus prop, plus return payload) and has a surface area of about 430 m^2. That is a bit more than 0.3 mT per m^2. So the heat shield should be less stressed than Apollo, even if the reentry path is similar to Apollo, which it will not be. Due to the delta wing, its going to be even shallower.
Many people worry that SpaceX will be taking a risk by transitioning at some point from the cash-producing Falcon 9 to the BFR. But there is one contrarian thought which I haven't read in this thread (or anywhere for that matter). Today's SpaceX is above all an organization that excels at designing and building innovative launch vehicles and spacecraft. After 16 F9 landings in a row, one can imagine a future where most flights use previously flown boosters. Today's design-and-build SpaceX is less relevant in such a future.Hence, the greatest long-term risk for SpaceX, in my view, would be if it were to stand still. And that's why I believe that the all-in transition to BFR makes perfect strategic as well as financial sense.
Quote from: Lumina on 10/05/2017 01:35 pmMany people worry that SpaceX will be taking a risk by transitioning at some point from the cash-producing Falcon 9 to the BFR. But there is one contrarian thought which I haven't read in this thread (or anywhere for that matter). Today's SpaceX is above all an organization that excels at designing and building innovative launch vehicles and spacecraft. After 16 F9 landings in a row, one can imagine a future where most flights use previously flown boosters. Today's design-and-build SpaceX is less relevant in such a future.Hence, the greatest long-term risk for SpaceX, in my view, would be if it were to stand still. And that's why I believe that the all-in transition to BFR makes perfect strategic as well as financial sense.Agreed. If they don't stay on the edge, they'll start bleeding those capable and driven employees that have made them so great.BFR in its various incarnations as well as all the necessary Mars infrastructure will keep them busy for a while.... And it'll be less enticing for SpaceX employees to join startups like Firefly if all those lesser vehicles are made obsolete by BFR... (Someone will make a rival for BFR eventually, tho)
Quote from: Robotbeat on 10/05/2017 01:41 pmQuote from: Lumina on 10/05/2017 01:35 pmMany people worry that SpaceX will be taking a risk by transitioning at some point from the cash-producing Falcon 9 to the BFR. But there is one contrarian thought which I haven't read in this thread (or anywhere for that matter). Today's SpaceX is above all an organization that excels at designing and building innovative launch vehicles and spacecraft. After 16 F9 landings in a row, one can imagine a future where most flights use previously flown boosters. Today's design-and-build SpaceX is less relevant in such a future.Hence, the greatest long-term risk for SpaceX, in my view, would be if it were to stand still. And that's why I believe that the all-in transition to BFR makes perfect strategic as well as financial sense.Agreed. If they don't stay on the edge, they'll start bleeding those capable and driven employees that have made them so great.BFR in its various incarnations as well as all the necessary Mars infrastructure will keep them busy for a while.... And it'll be less enticing for SpaceX employees to join startups like Firefly if all those lesser vehicles are made obsolete by BFR... (Someone will make a rival for BFR eventually, tho)That's not necessarily true. There will always be a place for smaller launchers, as there will always be rush payloads that are too small to economically be viable for a BFR launch. Timing a number of payloads to a single orbital inclination for one launch can and often is problematic.
That's not necessarily true. There will always be a place for smaller launchers, as there will always be rush payloads that are too small to economically be viable for a BFR launch. Timing a number of payloads to a single orbital inclination for one launch can and often is problematic.
Quote from: JasonAW3 on 10/05/2017 01:58 pmThat's not necessarily true. There will always be a place for smaller launchers, as there will always be rush payloads that are too small to economically be viable for a BFR launch. Timing a number of payloads to a single orbital inclination for one launch can and often is problematic.That's only true if the smaller launcher is cheaper than BFR. And if BFR comes close to the Elon's promise of being cheaper to launch than the Falcon 1, than this will be a real hurdle. You could get 1000x the payload of the Electron for the same price or even cheaper.
I really think half the reason Musk has considered NTR is to just keep Mueller happy.
Quote from: john smith 19 on 10/05/2017 08:17 amWhen you resort to including some (massive) costs in one side of your argument and not including them in the other you've pretty much lost the "moral high ground" and people are likely to view your arguments with doubt. I didn't introduce the numbers. I was responding to the person who did introduce those numbers. The point remains the same even with lower numbers. STS development in today's dollars was probably around $40 billion. BFR - a larger launch vehicle - at only $4 billion development I simply do not believe. Remember that SpaceX itself did not say "$4 billion", that came from someone's on this thread. Remember also that Mr. Musk said his company spent $1 billion just to develop Falcon 9 first stage landing.But this argument is hopeless, of course, because SpaceX won't tell us how much money it is spending, how big its debt really is, etc. - Ed Kyle
When you resort to including some (massive) costs in one side of your argument and not including them in the other you've pretty much lost the "moral high ground" and people are likely to view your arguments with doubt.
...SpaceX will have to build a factory, test sites, a new launch pad or two, a couple of giant recovery ships apparently, etc. - Ed Kyle
Quote from: edkyle99 on 10/05/2017 03:43 pm...SpaceX will have to build a factory, test sites, a new launch pad or two, a couple of giant recovery ships apparently, etc. - Ed KyleWhy would they need new recovery ships? BFR is intended to RTLS, and if they do want to land downrange the current ASDS would be fine. F9's landed footprint is already well over 20 meters, there's no need for more deck space.
Surface area is one thing, total cargo - the rockets - and center of mass is a totally different consideration. Wouldn't want to land perfectly centered then have the first swell that comes along capsize your barge.But I didn't get the impression that there were any plans to land the BFR stages on mobile platforms such as the barges used for the Falcon 9 first stage.
Solve it... with thinking outside the box... Load all the worlds ready to fly small payloads onto some common rotary mounting frame yet to be invented...Launch the "SmallSat special'Use more prop as needed for orbital plane changes and different orbits as needed...Time tankers to meet the ship at intervals... to partially refuel as needed during the delivery "route"...Once all the payloads are all delivered and the last tanker has left... fly it home...Put it back in the hanger and start loading the next months delivery payloads...Once a month... 12 times a year... Fly that one BFS to clear the backlog installed...Remember... while on orbit and with tankers available on call... They could run the fuel tanks way down near empty to minimize mass needing to change orbit...It could require one last tanker 'splash' before having enough fuel to land with... no big deal...Just saying... think outside the box when considering how to solve the worlds launch needs...
Quote from: envy887 on 10/05/2017 04:01 pmQuote from: edkyle99 on 10/05/2017 03:43 pm...SpaceX will have to build a factory, test sites, a new launch pad or two, a couple of giant recovery ships apparently, etc. - Ed KyleWhy would they need new recovery ships? BFR is intended to RTLS, and if they do want to land downrange the current ASDS would be fine. F9's landed footprint is already well over 20 meters, there's no need for more deck space.Agree BFR will always RTLS. I think ASDS is irrelevant. I don't take the offshore pads as barges or even part of the short term plan.