Quote from: nacnud on 06/10/2020 01:38 pmYou probably only need a few hundred m/s of landing propellant, if that.Is there so much friction loss because of the air? Otherwise, it's travelling >2,500 m/s forward there's some reduction necessary, especially including the gravity drag.
You probably only need a few hundred m/s of landing propellant, if that.
I think so, that's why it has wings, so it can stay lofted and slow down without needing as much ∆v as Falcon. On the down side it ends up much further downrange than Falcon. This is from memory of reading this forum not any insider knowledge so I could well be wrong.I seem to recall that New Glenn won't need an entry burn either.
But this makes my calculations more weird. Having less saved for return provides even more upward delta-v and New Glenn could go beyond 45 t to LEO...
Hi all,I did some rough calculations on the dimensions of New Glenn and I'm a bit confused:Given both New Glenn stages use a shared bulkhead, which makes sense in regard to the fuel temperature, the first stage should hold >1250 t (O/F ~ 3.3) of propellant and the upper stage about 230 t (O/F ~5.5). Adding some structural weight and the payload, we end up with a GLOW... or more like GSAW (gross stand around weight)... of ~1650 tons which is about the SL thrust the 7 BE-4s need to develop. The total size of the stages being ~49 m for the first stage excluding the interstage and ~25 for the second stage. Engine length ~5 m for the first and ~4 m for the second.Introducing on both stage 7 m of inter tank structure, it comes down to ~1050 t for the first and ~145 t for the second. With a GLOW of around 1300 t, yet only 1.3 TWR at launch. Possible but not much.Then, I included 3000 m/s of landing fuel in the first stage to be on the save side but what do you expect. Nonetheless, no shared bulkheads - does that makes sense to you?
You would really think they would be more open about their progress, freaking Boeing is better. Without this I feel like it will be harder for them to succeed long term. SpaceX is merely a household name while saying blue origin to people would seem like your talking crazy. Also both Elon and Jeff Bezos are well known people, each running a house hold company. Very disappointing to me
Quote from: Aeneas on 06/10/2020 01:07 pmHi all,I did some rough calculations on the dimensions of New Glenn and I'm a bit confused:Given both New Glenn stages use a shared bulkhead, which makes sense in regard to the fuel temperature, the first stage should hold >1250 t (O/F ~ 3.3) of propellant and the upper stage about 230 t (O/F ~5.5). Adding some structural weight and the payload, we end up with a GLOW... or more like GSAW (gross stand around weight)... of ~1650 tons which is about the SL thrust the 7 BE-4s need to develop. The total size of the stages being ~49 m for the first stage excluding the interstage and ~25 for the second stage. Engine length ~5 m for the first and ~4 m for the second.Introducing on both stage 7 m of inter tank structure, it comes down to ~1050 t for the first and ~145 t for the second. With a GLOW of around 1300 t, yet only 1.3 TWR at launch. Possible but not much.Then, I included 3000 m/s of landing fuel in the first stage to be on the save side but what do you expect. Nonetheless, no shared bulkheads - does that makes sense to you?Blue has shown cutaway graphics of New Glenn confirming that it has a common bulkhead in each stage. If you want to pixel-measure the stages to calculate the propellant mass, that would be informative.This image was posted earlier in this thread, and contains some measurements that are not info from Blue. All we officially know is the 7 m diameter and maybe the overall height.
That sounds a bit large, but New Glenn does have over 1700 tonnes of thrust. TWR of 1.25 or or even 1.20 is no problem.
Quote from: envy887 on 06/22/2020 02:37 amThat sounds a bit large, but New Glenn does have over 1700 tonnes of thrust. TWR of 1.25 or or even 1.20 is no problem.Sure, that would be possible. But if I size a rocket that would be capable to get 45 tons into orbit (incl. margins 9,400 m/s delta-v, average 330 s Isp for 1st and 450 s Isp for 2nd), with proper margins, it comes around with a TWR of ~1.45. And length of 1st stage of 40 m and 2nd at 22 m. Not 50 and 25.
Quote from: Aeneas on 06/24/2020 05:26 pmQuote from: envy887 on 06/22/2020 02:37 amThat sounds a bit large, but New Glenn does have over 1700 tonnes of thrust. TWR of 1.25 or or even 1.20 is no problem.Sure, that would be possible. But if I size a rocket that would be capable to get 45 tons into orbit (incl. margins 9,400 m/s delta-v, average 330 s Isp for 1st and 450 s Isp for 2nd), with proper margins, it comes around with a TWR of ~1.45. And length of 1st stage of 40 m and 2nd at 22 m. Not 50 and 25.New Glenn is a bit oversized for the payload mass Blue is advertising.
New Glenn has been identified as the launch vehicle selected to fly the first two modules of the Axiom station - https://www.reddit.com/r/BlueOrigin/comments/hk72xe/interview_with_the_module_manufacturer_of_the/
New GlennCapacity to GTO: 13 tonsCurrent launch date: End of 2021Confidence: LowOur estimated launch date: 3Q-4Q 2022
Eric Berger guesstimate New Glenn first launch is 3Q-4Q 2022: Sadly, none of the big rockets we hoped to see fly in 2020 actually willQuoteNew GlennCapacity to GTO: 13 tonsCurrent launch date: End of 2021Confidence: LowOur estimated launch date: 3Q-4Q 2022
New Glenn doesn't really have wings, but fins to guide in on re-entry and landing, like SpaceX uses grid fins and cold gas thrusters. It is coming back into earth's atmosphere engine first like SpaceX.
Quote from: spacenut on 06/11/2020 12:48 amNew Glenn doesn't really have wings, but fins to guide in on re-entry and landing, like SpaceX uses grid fins and cold gas thrusters. It is coming back into earth's atmosphere engine first like SpaceX. Did Blue Origin said what well be exact standard flight temperature for CH4 and LOX on New Glenn first stage. And if they plan to subcool them like SpaceX with Starship/SH ? What will be exact temperature of CH4/LOX after subcooling ?Did they also explain, why they changed their original plans with using 1 expendable BE-4 and CH4=LNG/LOX also for upper stage ?Now they want to use 2 expendable BE-3 engines flying on LH2/LOX for upper stage. Was it because they wanted better orbital insertion for big GTO comsats like Atlas V Centaur has with RL 10 engines. Can even hydrolox BE-3 offer better orbital insertion than methalox BE-4. Has it better ISP. Blue origin so far use it only for short suborbital flights. Or was sole reason they switch 2 BE-3 for 1 BE-4, that they didn't want to throw away more expansive BE-4 engine.Using hydrogen upper stage seems to look more difficult, because LH2 is much more difficult to storage and hydrogen also can not be subcooled.