Author Topic: New Glenn Engine-Out for EELV Ascent Profiles?  (Read 2621 times)

Offline sdsds

  • Senior Member
  • *****
  • Posts: 5466
  • "With peace and hope for all mankind."
  • Seattle
  • Liked: 571
  • Likes Given: 664
New Glenn Engine-Out for EELV Ascent Profiles?
« on: 09/13/2016 08:27 PM »
Splintering off from the other thread:
Does anybody else see a jarring contrast between going straight from the New Shepard to a New Glenn and Bezos' motto 'Gradatim Ferociter'? - Nothing gradual about such a jump from a glorified bottle rocket to a huge LV

I suspect New Glenn is the smallest orbital vehicle design using Blue's engines that can achieve mission success even with the loss of an engine over much of its ascent profile.

SpaceX claims engine out capability (for some payloads at least) over much or all of the F9 ascent. Blue will want to compete against that claim. Redundancy will be especially important since Blue engines are more complex than Merlin. Perhaps the propellant margin required for this may explain how New Glenn is "right-sized" for EELV payloads?
-- sdsds --

Offline ncb1397

  • Full Member
  • ****
  • Posts: 627
  • Liked: 302
  • Likes Given: 1
Re: New Glenn Engine-Out for EELV Ascent Profiles?
« Reply #1 on: 09/14/2016 01:23 AM »
Splintering off from the other thread:
Does anybody else see a jarring contrast between going straight from the New Shepard to a New Glenn and Bezos' motto 'Gradatim Ferociter'? - Nothing gradual about such a jump from a glorified bottle rocket to a huge LV

I suspect New Glenn is the smallest orbital vehicle design using Blue's engines that can achieve mission success even with the loss of an engine over much of its ascent profile.

SpaceX claims engine out capability (for some payloads at least) over much or all of the F9 ascent. Blue will want to compete against that claim. Redundancy will be especially important since Blue engines are more complex than Merlin. Perhaps the propellant margin required for this may explain how New Glenn is "right-sized" for EELV payloads?

Why not fly humans with co-manifested payloads. The comsat pays the majority of the launch cost while tourists pay whatever the market will support. If you can throw up a 5 mT satellite at $60 million and 10 paying customers at $3 million each, you get 1/2 more revenue from the tourists even though they don't pay that much(compared to rates today). The capsule at the top either has a payload bay or there is cargo space between the capsule and the upper stage(like dragon's trunk or Orion's USA).

On the other hand, with many comsats being just on the edge of F9s capabilities with re-use, you have to compromise the return trajectory and the first stage gets toasted. With extra margin's for re-use, you can get the first stage back in better shape by firing the engines longer to slow down prior to re-entry.
« Last Edit: 09/14/2016 01:25 AM by ncb1397 »

Offline brickmack

  • Full Member
  • *
  • Posts: 120
  • USA
  • Liked: 27
  • Likes Given: 3
Re: New Glenn Engine-Out for EELV Ascent Profiles?
« Reply #2 on: 09/14/2016 03:14 AM »
If they were going for EELV-class, I think a rocket based around a cluster of BE-3 engines would have made more sense. 7 BE-3s would have the same engine-out capability, and would produce a fair bit more thrust than an RS-68A (and its ISP is generally thought to be better). Expendable performance of the whole rocket would probably be at least as good as Delta IV M+, which is good enough to get a decent chunk of the market. Upgraded engines (like how SpaceX has so substantially improved Merlin performance, 3x the thrust and a ~10 second ISP increase since the first version) and maybe a 3 core version would put it into F9-DIVH territory.

Bezos explicitly stated a while back anyway that they don't intend to compete for EELV launches against ULA

Offline Robotbeat

  • Senior Member
  • *****
  • Posts: 25489
  • Minnesota
  • Liked: 5651
  • Likes Given: 4241
Re: New Glenn Engine-Out for EELV Ascent Profiles?
« Reply #3 on: 09/14/2016 03:18 AM »
But that's a lot of liquid hydrogen. First stage is better if it's methane.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline sdsds

  • Senior Member
  • *****
  • Posts: 5466
  • "With peace and hope for all mankind."
  • Seattle
  • Liked: 571
  • Likes Given: 664
Re: New Glenn Engine-Out for EELV Ascent Profiles?
« Reply #4 on: 09/14/2016 04:27 AM »
Bezos explicitly stated a while back anyway that they don't intend to compete for EELV launches against ULA

I don't know exactly what he has said. I do believe there is a subtle distinction between "EELV launches" and launches on a launcher that is the right size for EELV payloads. The first centers around a particular Defense Department funding mechanism which could draw to a close some day. The second reflects the on-going need for launches of what were called EELV Medium+ payloads. The difficult (for me at least) question is whether New Glenn, were it to lose propulsion from one engine during ascent, could nonetheless deliver a Medium+ payload to its intended orbit.
-- sdsds --

Offline ZachF

  • Full Member
  • *
  • Posts: 155
  • Park City, UT, USA, Earth
  • Liked: 65
  • Likes Given: 7
Re: New Glenn Engine-Out for EELV Ascent Profiles?
« Reply #5 on: 09/15/2016 01:28 AM »
But that's a lot of liquid hydrogen. First stage is better if it's methane.

Plus if you want re-usability, Hydrogen does some pretty nasty things to whatever it's stored in after a while...

Offline leaflion

  • Full Member
  • *
  • Posts: 102
  • United States
  • Liked: 50
  • Likes Given: 17
Re: New Glenn Engine-Out for EELV Ascent Profiles?
« Reply #6 on: 09/15/2016 06:31 AM »
New Shepard begs to differ...

Online AncientU

  • Senior Member
  • *****
  • Posts: 3429
  • Liked: 1984
  • Likes Given: 2763
Re: New Glenn Engine-Out for EELV Ascent Profiles?
« Reply #7 on: 09/15/2016 11:13 AM »
New Shepard begs to differ...

New Shepard is running the experiment to prove (or disprove) super-cryogen cycling limits.  She can beg to differ once empirical data is in hand.  So far, it's looking good... total cycles might be 10-20 at max? Probably need 100 to put this issue behind them.
"If we shared everything [we are working on] people would think we are insane!"
-- SpaceX friend of mlindner

Offline ZachF

  • Full Member
  • *
  • Posts: 155
  • Park City, UT, USA, Earth
  • Liked: 65
  • Likes Given: 7
Re: New Glenn Engine-Out for EELV Ascent Profiles?
« Reply #8 on: 09/15/2016 04:09 PM »
New Shepard begs to differ...

New Shepard is running the experiment to prove (or disprove) super-cryogen cycling limits.  She can beg to differ once empirical data is in hand.  So far, it's looking good... total cycles might be 10-20 at max? Probably need 100 to put this issue behind them.

Could be part of the reason why they chose Methalox for the first re-usable stage....

Offline Lars-J

  • Senior Member
  • *****
  • Posts: 2571
  • California
  • Liked: 2024
  • Likes Given: 1134
Re: New Glenn Engine-Out for EELV Ascent Profiles?
« Reply #9 on: 09/15/2016 04:59 PM »
But that's a lot of liquid hydrogen. First stage is better if it's methane.

Plus if you want re-usability, Hydrogen does some pretty nasty things to whatever it's stored in after a while...

New Shepard begs to differ...

Yes, New Shepard isn't exactly flying very often, is it? Only Blue knows exactly what kind of processing it needs between each flight to deal with any potential hydrogen issues.
« Last Edit: 09/15/2016 05:01 PM by Lars-J »

Offline hkultala

  • Full Member
  • ****
  • Posts: 452
  • Liked: 92
  • Likes Given: 16
Re: New Glenn Engine-Out for EELV Ascent Profiles?
« Reply #10 on: 09/15/2016 05:25 PM »
If they were going for EELV-class, I think a rocket based around a cluster of BE-3 engines would have made more sense. 7 BE-3s would have the same engine-out capability, and would produce a fair bit more thrust than an RS-68A (and its ISP is generally thought to be better). Expendable performance of the whole rocket would probably be at least as good as Delta IV M+,

No, only better than Delta IV Medium without solids.

And engine-out capasity is not only about having suitable amount of engines, it's also about having the margins to be able to take the increased gravity losses and still make it to orbit.

Quote
which is good enough to get a decent chunk of the market.

Which market?
Most GTO launches seem to be about 5.5 tonnes now, and it's not sure if 7- BE-3 first stage would be enough for that.

And Blue origin does not want to make expendable rockets. reusability costs payload.

Quote
Upgraded engines (like how SpaceX has so substantially improved Merlin performance, 3x the thrust and a ~10 second ISP increase since the first version)

There is no magic "upgraded engine" feature. SpaceX has managed to upgrade it's engines multiple times because originally it was so low-thrust and low-tech engine with huge margins. BE-3 is not Merlin 1C.

Quote
and maybe a 3 core version would put it into F9-DIVH territory.

Multiple cores is complicated and expensive, that's soemthing one really wants to avoid.



Price per thrust is just so bad in hydrogen engines that there is no sense in using them for first/booster stages. (yes, Delta IV uses them, but it has proved to be an uncompetitive rocket, way too expensive to survive real competition).


BE-4 gives about 5 times more thrust than BE-3 while only being something like 2x more expensive.


Offline hkultala

  • Full Member
  • ****
  • Posts: 452
  • Liked: 92
  • Likes Given: 16
Re: New Glenn Engine-Out for EELV Ascent Profiles?
« Reply #11 on: 09/15/2016 05:28 PM »

Why not fly humans with co-manifested payloads. The comsat pays the majority of the launch cost while tourists pay whatever the market will support. If you can throw up a 5 mT satellite at $60 million and 10 paying customers at $3 million each, you get 1/2 more revenue from the tourists even though they don't pay that much(compared to rates today). The capsule at the top either has a payload bay or there is cargo space between the capsule and the upper stage(like dragon's trunk or Orion's USA).


Humans to GTO to go through the van allen's belt multiple times?

That just makes no sense at all.

Resonable destinations to humans are either
1) LEO
2) space station on LEO
3) space station somewhere else than LEO
4) other space bodies(moon, mars etc)


but NOT GTO.

« Last Edit: 09/15/2016 05:29 PM by hkultala »

Online envy887

  • Full Member
  • ****
  • Posts: 1333
  • Liked: 551
  • Likes Given: 288
Re: New Glenn Engine-Out for EELV Ascent Profiles?
« Reply #12 on: 09/15/2016 08:53 PM »

Why not fly humans with co-manifested payloads. The comsat pays the majority of the launch cost while tourists pay whatever the market will support. If you can throw up a 5 mT satellite at $60 million and 10 paying customers at $3 million each, you get 1/2 more revenue from the tourists even though they don't pay that much(compared to rates today). The capsule at the top either has a payload bay or there is cargo space between the capsule and the upper stage(like dragon's trunk or Orion's USA).


Humans to GTO to go through the van allen's belt multiple times?

That just makes no sense at all.

Resonable destinations to humans are either
1) LEO
2) space station on LEO
3) space station somewhere else than LEO
4) other space bodies(moon, mars etc)


but NOT GTO.

LEO or low-medium orbits are probably a lot more interesting to tourists anyway, plus the capsule would have to sit on top for viable launch abort. In that situation, the capsule could separate during coast before the GTO burn, stay in LEO, and return in a few hours (instead of 16+ hours to the GSO ring and back).

A dragon trunk style PLF could support the capsule and protect the satcomm during launch, and then sep with the capsule at coast leaving the bare payload still attached to the upper stage to go on to GTO. The "trunk" could support cooling and power like Dragon's does, and detach before rentry.

Offline sdsds

  • Senior Member
  • *****
  • Posts: 5466
  • "With peace and hope for all mankind."
  • Seattle
  • Liked: 571
  • Likes Given: 664
Re: New Glenn Engine-Out for EELV Ascent Profiles?
« Reply #13 on: 09/17/2016 07:40 PM »
And engine-out capasity is not only about having suitable amount of engines, it's also about having the margins to be able to take the increased gravity losses and still make it to orbit.

Yes. I tried to make guesstimates to come up with a sense of how much margin is required in the case where the first stage loses one of seven engines. It doesn't look that bad. If the nominal ascent would have lost 1400 m/s to gravity drag, the off-nominal ascent might only lose 1600 m/s or so? And maybe the ascent to stage separation takes an additional minute or two?

That's assuming they don't have the option of running the remaining six engines in a contingency, 117% thrust level. If they had (and utilized) that option, the ascent profile could remain essentially unchanged, I think.
-- sdsds --

Tags: