Blue Origin thread.

[ment18]

9 minutes ago, sevenperforce said:

I am concerned about TWR and ascent profiles for when they try to man-rate this.

Can you explain this?  Lower total mass should help first stage, and more engines on the 2nd stage, depending on gimbal, could allow for some sort of engine out, maybe only later in the burn.

[sevenperforce]

10 minutes ago, ment18 said:

Can you explain this?  Lower total mass should help first stage, and more engines on the 2nd stage, depending on gimbal, could allow for some sort of engine out, maybe only later in the burn.

We won't really know until we get more specs, but chances are that with a lower TWR on the upper stage, the first stage will need to fly a more lofted trajectory. Lofted trajectories are good for recovery, but they are not great for abort. 

In an abort just before MECO-1, the capsule must separate from the upper stage and fire its abort motor. This places it in a very, very lofted trajectory, meaning it arcs far above the atmosphere and them comes in at a very steep angle. Steep angles are very high-gee, which could lead to serious injury or death for the occupants.

This, for example, is why the Boeing Starliner needs to fly on the DEC (dual-engine Centaur) rather than the SEC.

[Racescort666]

Here is my estimate for payload increase by switching to 2 BE-3U engines instead of a single BE-4:

• LEO:
  • Metholox BE-4: 45 000 kg
  • Hydrolox BE-3: 60 243 kg
• GTO:
  • Metholox BE-4: 13 000 kg
  • Hydrolox BE-3: 20 165 kg

There was some discussion about TWR with switching to 2 BE-3 engines but based on my estimates, it seems reasonable considering other launch vehicles. 

• LEO TWR:
  • Metholox BE-4: 0.71:1
  • Hydrolox BE-3: 0.29:1
• GTO TWR:
  • Metholox BE-4: 0.78:1
  • Hydrolox BE-3: 0.32:1

For reference, F9 is around 0.70:1 while Atlas V is around 0.30:1. Obviously this varies with payload but Centaur has very low thrust and Atlas V has a pretty big payload capacity.

Methodology and some discussion in the spoiler:

Spoiler

This estimate requires quite a number of assumptions since there isn't a whole lot of information out there on Blue Origin's capabilities so I tried to be on the conservative side for assumptions. Fortunately, LEO and GTO payload capacity are advertised so I had a good starting point. After beginning my investigation, my initial thoughts on New Glenn were "holy cow! this thing is a beast!" By my estimate, the upper stage carries around 345 476 kg of propellant. 

NG Upper stage: I made my initial estimates of the existing upper stage off of what little information is publicly available. I scaled the published pictures to get an upper stage length of 8.82 m. Assuming that the first blue band is where the stages separate and the engine/interstage is below that and the second stage fuel tank stops right at the edge of the fairing. We know that it is 7 m in diameter so assuming that the fuel tank wall is of negligible thickness, this is basically the volume of fuel the second stage carries. 

The mass of the fuel tank was estimated the same way I have done these estimations in the past, basically a mass per area of a cylinder. I used 20 kg/m2 to estimate the New Glenn fuel tank to weigh 5419 kg. The area weight is from the Space Shuttle ET (which is quite conservative considering the ET is structural). Centaur area weight is around 15 kg/m2.

The engines are where I had to make some big assumptions since there is almost nothing known about them besides the thrust. 

• BE-3:
  • Thrust: 490 kN (Published value, not adjusted for vacuum optimization. We know it's going to be higher and will probably affect the TWR which I used to get mass.)
  • TWR: 70:1 (TWR is kind of a shot in the dark, the J-2 has good TWR and there are a few other Hydrolox engines that have TWRs in this range but I've got no idea)
  • Mass: 714.3 kg (Based on TWR)
  • ISP: 440 s (This one was another estimate but probably a bit closer to reality. The J-2S was a tap-off cycle engine that supposedly would have had 451 s ISP. Looking at wikipedia, this ISP seems to be about in the middle of what has been built by others although it might be a bit low for how the BE-3 performs.)
  • FR: 6:1 (Common Hydrolox mix ratio, I use this value to get an average density of the propellant)
• BE-4
  • Thrust: 2400 kN (Published value, not adjusted for vacuum optimization. We know it's going to be higher and will probably affect the TWR which I used to get mass.)
  • TWR: 150:1 (Again, this is kind of a shot in the dark. The consensus seems to be that the Raptor will have a TWR of 198.5:1 or higher so I took a more conservative estimate)
  • Mass: 1632.7 kg (Again, based on TWR)
  • ISP: 365 s (Another shot in the dark, SpaceX claims the Raptor Vacuum will be 382 s so I took a slightly more conservative estimate)
  • FR: 3.8:1 (Metholox mix ratio for Raptor, there's no reason to assume that BE-4 will be significantly different)

From here, I have enough information to estimate the mass and dV of the current New Glenn second stage. The fuel, fuel tank, and engine masses for the BE-4 powered stage stays the same regardless of orbit so only the payload mass change affects the dV, LEO: 6770 m/s, GTO: 9835 m/s Thought #2: this thing packs quite the punch for dV. So to figure out the payload change, I use the same wet mass and dV in the rocket equation to figure out the new fuel mass/dry mass with the increased ISP. Fuel tank mass is a function of fuel mass (fuel mass/fuel density = volume -> area -> fuel tank mass). 

At 7 m in diameter, New Glenn is pretty volume efficient. By switching to Hydrolox, there appears to be a pretty big improvement and it doesn't look like it will have a big impact to the configuration. The fuel tank about doubles in length but there's a pretty big hit to second stage TWR. I don't really know how big the BE-3 is so I wasn't able to verify but adding more upper stage engines could probably compensate for this and still have a payload gain.

Anyway, if any of my assumptions are incorrect or if there's better information out there that I should be using, let me know and I'll update my spreadsheet. I also want to point out that I intended to look into this last Thursday, forgot, came back and tried doing it last night, got way too deep into the equations, stayed up well past midnight, then finally simplified it today. I broke my brain a bit.

 

[tater]

37 minutes ago, Racescort666 said:

Here is my estimate for payload increase by switching to 2 BE-3U engines instead of a single BE-4:

• LEO:
  • Metholox BE-4: 45 000 kg
  • Hydrolox BE-3: 60 243 kg
• GTO:
  • Metholox BE-4: 13 000 kg
  • Hydrolox BE-3: 20 165 kg

There was some discussion about TWR with switching to 2 BE-3 engines but based on my estimates, it seems reasonable considering other launch vehicles. 

• LEO TWR:
  • Metholox BE-4: 0.71:1
  • Hydrolox BE-3: 0.29:1
• GTO TWR:
  • Metholox BE-4: 0.78:1
  • Hydrolox BE-3: 0.32:1

For reference, F9 is around 0.70:1 while Atlas V is around 0.30:1. Obviously this varies with payload but Centaur has very low thrust and Atlas V has a pretty big payload capacity.

Methodology and some discussion in the spoiler:

  Reveal hidden contents

This estimate requires quite a number of assumptions since there isn't a whole lot of information out there on Blue Origin's capabilities so I tried to be on the conservative side for assumptions. Fortunately, LEO and GTO payload capacity are advertised so I had a good starting point. After beginning my investigation, my initial thoughts on New Glenn were "holy cow! this thing is a beast!" By my estimate, the upper stage carries around 345 476 kg of propellant. 

NG Upper stage: I made my initial estimates of the existing upper stage off of what little information is publicly available. I scaled the published pictures to get an upper stage length of 8.82 m. Assuming that the first blue band is where the stages separate and the engine/interstage is below that and the second stage fuel tank stops right at the edge of the fairing. We know that it is 7 m in diameter so assuming that the fuel tank wall is of negligible thickness, this is basically the volume of fuel the second stage carries. 

The mass of the fuel tank was estimated the same way I have done these estimations in the past, basically a mass per area of a cylinder. I used 20 kg/m2 to estimate the New Glenn fuel tank to weigh 5419 kg. The area weight is from the Space Shuttle ET (which is quite conservative considering the ET is structural). Centaur area weight is around 15 kg/m2.

The engines are where I had to make some big assumptions since there is almost nothing known about them besides the thrust. 

• BE-3:
  • Thrust: 490 kN (Published value, not adjusted for vacuum optimization. We know it's going to be higher and will probably affect the TWR which I used to get mass.)
  • TWR: 70:1 (TWR is kind of a shot in the dark, the J-2 has good TWR and there are a few other Hydrolox engines that have TWRs in this range but I've got no idea)
  • Mass: 714.3 kg (Based on TWR)
  • ISP: 440 s (This one was another estimate but probably a bit closer to reality. The J-2S was a tap-off cycle engine that supposedly would have had 451 s ISP. Looking at wikipedia, this ISP seems to be about in the middle of what has been built by others although it might be a bit low for how the BE-3 performs.)
  • FR: 6:1 (Common Hydrolox mix ratio, I use this value to get an average density of the propellant)
• BE-4
  • Thrust: 2400 kN (Published value, not adjusted for vacuum optimization. We know it's going to be higher and will probably affect the TWR which I used to get mass.)
  • TWR: 150:1 (Again, this is kind of a shot in the dark. The consensus seems to be that the Raptor will have a TWR of 198.5:1 or higher so I took a more conservative estimate)
  • Mass: 1632.7 kg (Again, based on TWR)
  • ISP: 365 s (Another shot in the dark, SpaceX claims the Raptor Vacuum will be 382 s so I took a slightly more conservative estimate)
  • FR: 3.8:1 (Metholox mix ratio for Raptor, there's no reason to assume that BE-4 will be significantly different)

From here, I have enough information to estimate the mass and dV of the current New Glenn second stage. The fuel, fuel tank, and engine masses for the BE-4 powered stage stays the same regardless of orbit so only the payload mass change affects the dV, LEO: 6770 m/s, GTO: 9835 m/s Thought #2: this thing packs quite the punch for dV. So to figure out the payload change, I use the same wet mass and dV in the rocket equation to figure out the new fuel mass/dry mass with the increased ISP. Fuel tank mass is a function of fuel mass (fuel mass/fuel density = volume -> area -> fuel tank mass). 

At 7 m in diameter, New Glenn is pretty volume efficient. By switching to Hydrolox, there appears to be a pretty big improvement and it doesn't look like it will have a big impact to the configuration. The fuel tank about doubles in length but there's a pretty big hit to second stage TWR. I don't really know how big the BE-3 is so I wasn't able to verify but adding more upper stage engines could probably compensate for this and still have a payload gain.

Anyway, if any of my assumptions are incorrect or if there's better information out there that I should be using, let me know and I'll update my spreadsheet. I also want to point out that I intended to look into this last Thursday, forgot, came back and tried doing it last night, got way too deep into the equations, stayed up well past midnight, then finally simplified it today. I broke my brain a bit.

 

Wow. ULA should be afraid. So should SpaceX, frankly. And SLS.

Bezos is not screwing around. 45 tons was already a lot, given the huge fairing. 60 means that you can literally put something Centaur like on top (stage 3 of NG), AND Orion, if they ant to play the political game. Assuming reuse, and competitive prices (ie: aimed at FH), NG can loft more than SLS in 2 launches, and the stuff it can fly can be the same size (worst cae they make a bigger fairing, on the off chance there are some 8.4m cargoes designed for the nonexistent cargo version).

I honestly think that Musk's Mars focus has accidentally helped him at least in the next decade or so. ITS, now BFR/BFS is the next gen vehicle they actually need to compete with BO.

Interesting times.

BTW, I have seen much higher vacuum thrust values suggested for Be-3U than 450 kN. Over 600. RL-10 is 110, BTW (right?).

 

Edited April 3, 2018 by tater

[tater]

Duh, they can put ACES on top... with a be-3u.

[sevenperforce]

1 hour ago, tater said:

Wow. ULA should be afraid. So should SpaceX, frankly. And SLS.

Bezos is not screwing around. 45 tons was already a lot, given the huge fairing. 60 means that you can literally put something Centaur like on top (stage 3 of NG), AND Orion, if they ant to play the political game. Assuming reuse, and competitive prices (ie: aimed at FH), NG can loft more than SLS in 2 launches, and the stuff it can fly can be the same size (worst cae they make a bigger fairing, on the off chance there are some 8.4m cargoes designed for the nonexistent cargo version).

I honestly think that Musk's Mars focus has accidentally helped him at least in the next decade or so. ITS, now BFR/BFS is the next gen vehicle they actually need to compete with BO.

Interesting times.

BTW, I have seen much higher vacuum thrust values suggested for Be-3U than 450 kN. Over 600. RL-10 is 110, BTW (right?).

An SSME's thrust grew by 23% from SL to vacuum, and you're going to see a much bigger jump with a vacuum-optimized bell. 600 kN should be no problem. 

[Racescort666]

1 hour ago, tater said:

BTW, I have seen much higher vacuum thrust values suggested for Be-3U than 450 kN. Over 600. RL-10 is 110, BTW (right?).

I have been using 99.2 kN since most of my comparisons have been to Centaur which uses RL10A-4-2. I believe the DCSS has slightly more thrust at 110 kN with the RL10B-2. I assume this is because RL10B has the extendable engine bell, weighs more, and has better ISP. 

29 minutes ago, sevenperforce said:

600 kN should be no problem.

As for BE-3U, it appears to be a really solid choice. At 600 kN (I really wish I had a better mass estimate), the new payload is still around 60t (59 922 kg, GTO is 19 844 kg) and the engine mass jumps 160 kg since it's based on TWR. Second Stage TWR is LEO: 0.35:1 and GTO 0.39:1 both are pretty reasonable while a 3 or 4 engine version gets you back in the neighborhood of the original TWR. 

Edited April 3, 2018 by Racescort666
added GTO payload w/ new thrust

[tater]

NG. 3rd stage, with a tapering interstage (like Saturn V). CST-100 on top. Inside interstage? BA330. Upper stage still has around 30 tons.

[tater]

Second NG lofts a 60 ton ACES. You can now push the thing someplace.

This could very much be like the ula/Bigelow vid that shows BA330 in LEO for testing, then Vulcan launches an ACES, then a second one which refills the first, then it flies the hab tonlinar orbit. This does the same, but lofts a full ACES.

[Ultimate Steve]

Any word on projected cost? That is the one remaining thing that needs to be seen to make NG competitive with FH. NG's capabilities are ahead of FH (unless you upgrade FH's payload adapter, and count the fact that FH is flying), but it will only seriously threaten the stability of the FH system if it costs significantly less than 150M per flight.

Although, there is another positive to this... It gives SpaceX a reason to get their next generation vehicle up sooner!

[tater]

It will be competitive. Then we’ll have 2 companies saying that they don’t know how to make an X hundred million $ plus rocket that you throw away...

 

[MaverickSawyer]

On 3/22/2018 at 2:15 PM, CatastrophicFailure said:

The old blockhouse looks pretty clean, wonder if they’re keeping it?

They have to. Historical structure.

 

On 3/29/2018 at 10:10 AM, tater said:

If AJ isn't afraid, they should be.

Aerojet Rockedyne is, quite frankly, not even remotely concerned with making new products anymore. They're making money hand over fist by selling off their Rancho Cordova, CA, facility for being turned into housing developments, and they're unwilling to invest the capital they need to in order to turn AR-1 from a paper engine into hardware. Trust me, used to live in the area and still have family friends who work for them. The stories coming out of the Rancho plant... *shudders* It's classic Corporate Nightmare now...

Besides, they're pretty much out of the running for Vulcan, anyhow. ULA has designed the tankage for metholox, so they'd have a fairly hefty delay to shift back to kerolox tankage.

 

As for NG... I have heard from some folks in the know that it's meant to be an "orbital pickup truck" more than anything else. Jeff has stated he wants to create the infrastructure needed to do significant amounts of upmass. And that's why NG will be the smallest of the Blue Origin orbital launchers.

[sh1pman]

4 hours ago, MaverickSawyer said:

As for NG... I have heard from some folks in the know that it's meant to be an "orbital pickup truck" more than anything else. Jeff has stated he wants to create the infrastructure needed to do significant amounts of upmass. And that's why NG will be the smallest of the Blue Origin orbital launchers.

Blue Origin's smallest pickup truck:

(sorry)

[CatastrophicFailure]

8 hours ago, MaverickSawyer said:

They have to. Historical structure.

Irony of having a historical structure within the immediate blast radius of a really big rocket... 

3 hours ago, sh1pman said:

Blue Origin's smallest pickup truck:

Elon: “hold my nonalcoholic malt beverage...”

competition is good. If these guys teamed up they could probably rule the galaxy. 

[sh1pman]

4 minutes ago, CatastrophicFailure said:

Irony of having a historical structure within the immediate blast radius of a really big rocket... 

Elon: “hold my nonalcoholic malt beverage...”

competition is good. If these guys teamed up they could probably rule the galaxy. 

New Armstrong: Sup!

[monophonic]

17 minutes ago, CatastrophicFailure said:

If these guys teamed up they could probably rule the galaxy. 

Always two there are.

[sevenperforce]

1 hour ago, sh1pman said:

New Armstrong: Sup!

Bigger Falcon Rocket: "Oh, I didn't see you there."

Edited April 4, 2018 by sevenperforce

[Snark]

Folks, I'm sure we can all enjoy a funny joke as much as the next person, but this is the Blue Origin thread, not the Funny Dueling Internet Images thread, and it's kinda getting derailed here.

Enough is enough.  Can we try to stick at least reasonably close to the topic, please?  Thank you. 

[tater]

So how big do you think the bell of a Be-3U will be? They have 7m of stage 2 diameter to play with, and are using 2xBe-3U. That leaves room for a couple sea level engines should they ever mess with recovery.

[sevenperforce]

6 minutes ago, tater said:

So how big do you think the bell of a Be-3U will be? They have 7m of stage 2 diameter to play with, and are using 2xBe-3U. That leaves room for a couple sea level engines should they ever mess with recovery.

Depends more than anything else on the chamber pressure of a SL BE-3. BE-3 is the first combustion-tapoff turbopump engine to ever fly, so there is no good way to estimate its chamber pressure. But given its high SL throttleability, I'm guessing they have a pretty high chamber pressure, which means a somewhat smaller engine bell than a lower-chamber-pressure solution.

[tater]

I have to assume that Blue wants upper stage reuse as well. The 2 options of course are returning stage 2 (BFS), or perhaps leaving stage 2 in space. The latter works for some stages, but without refilling it's sort of pointless, and you end up wasting more stages than you reuse. I suppose there is a third option, reusing them as habitable volume. This presents the same issues as making a tug out of stage 2, in that all your stages are in different orbits, making them effectively useless.

[Elthy]

40 minutes ago, sevenperforce said:

which means a somewhat smaller engine bell than a lower-chamber-pressure solution.

Isnt it the other way around? Lavalnozzles try to expand to ambient pressure, a higher chamber pressure means you need a bigger bell to get most of the efficency out of your engine...

[tater]

I wonder if ULA bails on Be-4... How can being wed to BO be to their advantage, when NG is going to stomp Vulcan? Think about it. They will now have a cryo upper stage. Centaur is the best thing about ULA, frankly, and BO is going to build one that could not possibly cost more than Centaur (given that RL-10 engines cost as much as a first stage in some cases). heck, a 7m cryo stage starts looking like an EUS replacement, if they are looking for a stage without 100-150 M$ worth of engines on it.

Edited April 4, 2018 by tater

[sevenperforce]

53 minutes ago, Elthy said:

Isnt it the other way around? Lavalnozzles try to expand to ambient pressure, a higher chamber pressure means you need a bigger bell to get most of the efficency out of your engine...

Well, yes, but I was speaking in comparison to the SL-expanded engine. Sorry for not making that clear.

Nozzle area ratio is a function of pressure drop ratio. Given an engine that comes in a SL-expanded variant and a vacuum-expanded variant, the difference in nozzle area ratios (and, correspondingly, the sizes of the nozzles) is going to decrease as the pressure increases.

An engine with relatively low chamber pressure has a moderate pressure drop at SL and a significantly greater pressure drop in vacuum, so its vacuum variant is going to need to be much much larger than its SL variant in order to take advantage. An engine with a much higher chamber pressure has less of a pressure drop between SL and vacuum, and so the nozzles will be closer in size.

All that to say: if the BE-3 was a low-chamber-pressure engine, then we would expect to see a very large vacuum nozzle in comparison to the SL nozzle. But since the BE-3 is deeply throttleable, which means it is high-chamber-pressure, then the vacuum nozzle will not be quite so gigantic, since most of the expansion has already happened in a SL-sized nozzle.

20 minutes ago, tater said:

I wonder if ULA bails on Be-4... How can being wed to BO be to their advantage, when NG is going to stomp Vulcan? Think about it. They will not have a cryo upper stage. Centaur is the best thing about ULA, frankly, and BO is going to build one that could not possibly cost more than Centaur (given that RL-10 engines cost as much as a first stage in some cases). heck, a 7m cryo stage starts looking like an EUS replacement, if they are looking for a stage without 100-150 M$ worth of engines on it.

Since when is Vulcan not going to have a Centaur upper stage?

ULA needs Vulcan to remain competitive at all.

Edited April 4, 2018 by sevenperforce

[tater]

37 minutes ago, sevenperforce said:

Since when is Vulcan not going to have a Centaur upper stage?

Sorry, a typo of noT for noW. BO will NOW have a cryo upper stage.

 

37 minutes ago, sevenperforce said:

ULA needs Vulcan to remain competitive at all.

Yeah, I am wondering if they go with AJ just to not be tied to BO.