Author Topic: New Glenn: Blue Origin Announcement of Orbital Rocket Plan  (Read 1105233 times)

Offline pippin

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #580 on: 03/19/2017 12:56 am »
@Lars-J: Sorry, I don't see that. SpaceX is clearly optimizing differently from BO, so I don't think this is OT.
Merlin is a kerolox gas generator engine and after all their optimizations has an extremely tweaked ISP for that and their next engine will use the most challenging cycle ever tried.
Contrast that to BE-4 which for now uses relatively low pressure and the most simple staged combustion cycle they could use.
SpaceX tweaks the mass fraction for stage 1, too, subcooled lox, common bulkhead,... there's a lot you could simplify if you didn't care about mass fraction.
Hoverslam landing minimized fuel required for landing (compare to BO, again).
And FH, which would be more alike NewGlenn WRT performance/size (oversized LV but reusing most of it) has obviously been a low priority project for years.

No, SpaceX have started exactly where BO is now in terms of attitude towards performance optimization and they have completely turned around.
Which is exactly the reason that makes me wonder what BO will do over time.

Maybe it simply makes sense to start with lots of margin when you don't have the deep experience yet but all evidence I see is that people actually flying LVs find tweaking performance more cost effective than growing simpler boosters which makes me tend towards believing performance optimization probably _is_ cost effective.
The one exception, again, is Ariane. They are not tweaked to the max and they are stepping back even more even though they do have a lot of experience.
But then it's not their own money, they get all the development effort paid for...
« Last Edit: 03/19/2017 01:02 am by pippin »

Offline TrevorMonty

The NG wasn't developed to service existing market but for a new market. Payloads direct to lunar surface, low cost HSF to LEO and maybe BLEO (DSH). Whether these new markets materialise we will have to wait and see, in mean time sell a few launches to existing market.


Offline Lars-J

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #582 on: 03/19/2017 01:50 am »
Maybe it simply makes sense to start with lots of margin when you don't have the deep experience yet but all evidence I see is that people actually flying LVs find tweaking performance more cost effective than growing simpler boosters which makes me tend towards believing performance optimization probably _is_ cost effective.

What determines how cost effective a reusable system is how cheap/fast it is to process for reflight. NOT performance tweaks, they will only have a minimal effect in comparison.

People need leave the expendable thinking behind. New Glenn is not an expendable launcher. (Except for the upper stage, which I expect will be much more typical of an upper stage)
« Last Edit: 03/19/2017 01:53 am by Lars-J »

Offline pippin

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #583 on: 03/19/2017 01:52 am »
We don't know that, yet. Nobody except SpaceX has any data.
And there's capital cost and capital at risk for large, reusable boosters, too. So many variables (read Space Ghost's post above).
Nobody knows which approach is most cost effective, there are just assumptions.
« Last Edit: 03/19/2017 01:56 am by pippin »

Offline Exastro

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #584 on: 03/19/2017 03:23 am »
SX and BO face very different incentives with regard to performance optimization.  The F9 was originally too small to address the GEO market.  SX had to increase its performance to do that.  What were their alternatives?  Add a third stage?  Develop a hydrolox engine and upper stage?  Add solid strap-ons?  Go to a whole new rocket with a larger diameter core with more engines and no ability to transport by road?  Use the triple-core Heavy configuration for everything beyond LEO?   None of those seem practical if low cost is the goal.  So they tweaked the Merlin for more thrust and used that to allow for stretched stages and bigger tanks.  I haven't seen the analysis, but it's easy to imagine that was the lowest-cost approach.

For BO and the NG it's different: going with a large, powerful core and having paid up-front the cost of putting the factory and test stand very close to the pad, they have more than enough performance out of the gate for even the most massive GEO payloads. 

So it seems likely that NG's performance won't grow anything like the way F9's did. 

Offline pippin

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #585 on: 03/19/2017 03:29 am »
Sure, that's the approach.
What we don't know yet, though, is whether NG will be cost competitive with the highly optimized F9/FH or other LVs. Only time will tell, that's the point.

I understand what BO is trying to do but none of us and probably not even BO themselves know at this point what the actual costs will be, there's still a lot of uncertainty in there.
One big topic will be reliability. We've seen with SpaceX and others that failures often happen in places you didn't expect them to so being conservative in your design doesn't necessarily prevent them.

Offline Chasm

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #586 on: 03/19/2017 05:17 am »
The nice thing about everyone using different approaches is that we'll find out how well they work, or rather for what.


Why get rockets much more complex and optimized over time? I'd say it's always a similar story.
The rocket has to launch soon and needs to work from the beginning, delivering a given payload.
Relatively recent is that we are talking about a commercial vendor with lots of competition, so let's also try for the low end of a given price range. The only really new thing is this one: The first stage must be reusable and actually will be reused in the real world. This reshuffles the optimizations a lot.
"Good enough" choices are safer and faster but still leave room for future improvements. Cutting edge technology is a risk. Time to market is money and unscheduled fireworks bad for customer confidence.


Then there are external influences. That the BE-4 apparently gained ~1/3 more thrust to meed ULAs requirements, that must have changed the NG design quite a bit. Same with the requirement to build their own launch site, that removed some constraints but added others.


I fully expect that NG will change over time. Or in other words, I doubt that just two NG first stages get build and then (re)launched for the next decade or so.

Offline hkultala

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #587 on: 03/19/2017 05:22 am »
One big topic will be reliability. We've seen with SpaceX and others that failures often happen in places you didn't expect them to so being conservative in your design doesn't necessarily prevent them.

The reality does not meet your beliefs here.

AMOS 6 failure was directly related to
1) using new materials(carbon fiber) in the helium tanks
2) using subcooled propellant.

Neither of these two things are conservative.

Conservative design is a design which MINIMIZES those unexpected places.
« Last Edit: 03/19/2017 05:24 am by hkultala »

Offline hkultala

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #588 on: 03/19/2017 05:29 am »
No, SpaceX have started exactly where BO is now in terms of attitude towards performance optimization and they have completely turned around.

wrong. SpaceX started practically without ANY performance optimizations, they started with a very weak very low-isp gg engine that was just cheap. And they originally selected the simples possible upper stage engine, going to pressure-fed, only using gg upper stage engine in their second rocket.

BO selecting to use staged combustion means they are MUCH HIGHER LEVEL of performance optimizations.

Offline TrevorMonty

One big topic will be reliability. We've seen with SpaceX and others that failures often happen in places you didn't expect them to so being conservative in your design doesn't necessarily prevent them.

The reality does not meet your beliefs here.

AMOS 6 failure was directly related to
1) using new materials(carbon fiber) in the helium tanks
2) using subcooled propellant.

Neither of these two things are conservative.

Conservative design is a design which MINIMIZES those unexpected places.
NG will use autogenous for pressurisation, so exploding He tanks shouldn't be issue.

Offline FutureSpaceTourist

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #590 on: 03/19/2017 07:10 am »
The nice thing about everyone using different approaches is that we'll find out how well they work, or rather for what.

Trouble is it can be very hard to distinguish between the inherent potential of an approach from how well a particular organisation executes it. SpaceX have at least had years and dozens of launches to iterate on theirs. Could be a decade before Blue Origin have had similar time and experience.

Having said that, I've been impressed with how well the NS flight tests have gone. Yes it's 'only' suborbital but I think it's still a good indicator of their technical prowess and bodes well for NG. I do t think they'll be worrying about running out of funds for a while either!

Offline guckyfan

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #591 on: 03/19/2017 09:04 am »

Trouble is it can be very hard to distinguish between the inherent potential of an approach from how well a particular organisation executes it. SpaceX have at least had years and dozens of launches to iterate on theirs. Could be a decade before Blue Origin have had similar time and experience.

If BO pulls it off at all it can get only better with experience. Please don't take my wording as doubt they can. It may not work on first try but they will get there.

Offline AncientU

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #592 on: 03/19/2017 12:14 pm »
One big topic will be reliability. We've seen with SpaceX and others that failures often happen in places you didn't expect them to so being conservative in your design doesn't necessarily prevent them.

The reality does not meet your beliefs here.

AMOS 6 failure was directly related to
1) using new materials(carbon fiber) in the helium tanks
2) using subcooled propellant.

Neither of these two things are conservative.

Conservative design is a design which MINIMIZES those unexpected places.

There is nothing conservative about building a company's first orbital rocket using seven oxygen-rich staged combustion engines and a seven meter core... with landing legs and a ship under full steam cruising down range. 

Plenty room for 'unexpected places' in this approach.
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Offline woods170

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #593 on: 03/19/2017 12:25 pm »
It seems strange that BO would consider ignoring SX's hypersonic retro-propulsion experience in even the short term; while not quite being a classic 1960s plug nozzle solution, it seems like a good - and cheap - engineering compromise. Also, I see no hint of SX attempting to patent their gradual, though ferocious, approach.
... Because blue origin has been stuck with sub orbital Rockets for so long they don't truly understand the importance of mass fraction. Maybe. I dunno.
You really should know better than that. Blue is hiring/has hired real professionals in the field of rocketry. They very much understand the importance of mass fraction.
That is an unfair reading of my post. Someone offered a conundrum, and I posited a /possible/ answer. And it's not that they don't understand what mass fraction is. I think the overall industry (well, Boeing and NASA) underestimates the importance of mass fraction, IMHO.

SpaceX has an almost obsessive grasp on mass fraction when compared to the rest of the industry. I think they're basically right. While adding more dry mass can reduce delta-V needed for things, you're just better off with very high mass fractions.

This is not saying that Blue Origin is stupid, just that I think their prior experience could tend to bias them toward heavier designs. JMHO.

Fair enough. Thanks for clearing up what you were getting at.

Offline AncientU

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #594 on: 03/19/2017 12:42 pm »
Been reading these posts and am not sure if Jim's comments were understood.

Nor the basic differences BO/SX that involve them. Here's a try to get the point across.

Most effective use of a LV's delta-v will be in staging chosen for the desired trajectory orbit uncompromised.

You could lift the vehicle extending its downrange still further. The benefit is to have a longer, stretched out, coast where a large drag coefficient of a larger vehicle passively dissipates kinetic energy. Also, the EI is more gradual, and the structural/thermal design can be differently used in reuse. For different "heating damage".

As opposed to a smaller, lighter vehicle limited to a lofted trajectory that buffers a more abrupt EI by use of retropropulsion. With different structural/thermal design and "heating damage" mitigation. Consistent with alternative use as an efficient ELV. Also, since the lofted trajectory doesn't go as far down range, selective RTLS reuse is just another added cost to minimize CONOPs complexity.

Both vehicles are competently designed, just chose differently. NG's mass additions are for recovery and to insure stage integrity over reuse, and props/trajectory are to achieve vehicle performance with least given to recovery. F9's mass additions are for recovery, while props/trajectory are limited in addition for vehicle integrity / recovery / downrange.
...

Thanks for the helpful narrative.

The questions still remain, though, concerning the amount of skin temperature rise (reentry energy absorbed) and the heat transfer mechanisms available to reject that energy.  A less abrupt entry interface slows the heat rate, but not the net energy absorbed, right?  Only if there is a reasonably efficient heat rejection mechanism can a temperature excursion in the skin be avoided.  Assuming an aluminum alloy skin, not much heat can be absorbed before structural integrity is compromised.  Going to titanium or an ablative coating might be required...
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Offline pippin

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #595 on: 03/19/2017 12:50 pm »
Well, given the size of the vehicle they could probably evaporate and vent some lox and fuel as a heat sink

Offline Robotbeat

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #596 on: 03/19/2017 01:00 pm »
No, SpaceX have started exactly where BO is now in terms of attitude towards performance optimization and they have completely turned around.

wrong. SpaceX started practically without ANY performance optimizations, they started with a very weak very low-isp gg engine that was just cheap. And they originally selected the simples possible upper stage engine, going to pressure-fed, only using gg upper stage engine in their second rocket.

BO selecting to use staged combustion means they are MUCH HIGHER LEVEL of performance optimizations.
Blue Origin used Isp to get the performance needed instead of mass fraction. An interesting point: for a single-engine suborbital rocket, that means you need much less throttling capability since your rocket's mass changes a lot less during flight. Biases you toward higher dry mass, since aerodynamic flaps don't change mass during flight (but using just more propellant to do the same thing DOES change your mass).
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Offline AncientU

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #597 on: 03/19/2017 01:38 pm »
Well, given the size of the vehicle they could probably evaporate and vent some lox and fuel as a heat sink

Right.  I've considered active cooling, too, but that is a quite complex thermodynamic process (cryogenic liquid on room temperature metal doesn't even wet the surface -- a vapor film 'protects' the liquid from absorbing heat except by radiative heat transfer, thus the heat transfer coefficient drops drastically below sub-cooled nucleate boiling or bulk boiling.  To get good radiative heat transfer, the heated element (skin in this case) has to undergo a significant temperature rise (radiative heat transfer goes at the 4th power of temperature.)  Physical systems to implement it add complexity and mass.  It was considered for X-15, and Shuttle too, I believe, but was abandoned as too difficult.
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Offline pippin

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #598 on: 03/19/2017 01:53 pm »
Yea. Plus it's a bit of a conflict since before and during launch you want the skin to rather be somewhat insulating.
It always boils down to "space is hard".

Offline AncientU

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #599 on: 03/19/2017 02:14 pm »
Here is an article on the X-15 which might be a reasonable analog of the skin conditions to be expected.  It was fabricated of Inconel-X and still had a range of issues, even though the skin could withstand over 1000F temperatures.

Quote
The basic (X-15) structure is a conventional monocoque design, in which the primary loads are carried in the external skin of the fuselage and wing. The fuselage skin also forms the outer shell of the propellant tanks. Thus, it must withstand the stresses from propellant weight as well as from internal tank pressurization. To absorb heat input, skin thicknesses on the forward fuselage are about three times those near the tail section. Fifteen feet aft from the nose, skin thickness is sized by load, rather than by heating, and is comparable to that of aluminum structure.

An important feature of the structural design is that only a small amount of the heat absorbed by the external skin is conducted, or radiated, to the internal structure. Consequently, much of the internal structure of the fuselage is of titanium and aluminum. Extensive use is made of corrugations and beading, to allow for uneven thermal expansion between external skin and internal structure.

Quote
A new element was also added to structural design, for with the heat-sink concept, the time of exposure became the critical parameter that established the amount of heat flow into the external structure when exposed to a 2500° F airflow. In areas that carry only small aerodynamic loads, Inconel X can withstand considerably more than 1200° F, perhaps 1600° F. The sharp leading edge on the vertical fin has withstood 1500° F, and one non-load-carrying section of the wing skin has successfully endured 1325° F. These temperatures are experienced for only brief periods of time, however. Prolonged exposure would eventually cause these temperatures to be conducted to load-carrying members, and thus impair the structural integrity of the X-15.

The structural design requires a careful balancing between the amount of material required to carry the load and that needed to absorb the heat flow. On a typical flight, the structure near the nose experiences 20 times as much heat input as the aft end. In regions of high heat input -fuselage nose, wing leading edge, tail leading edge- solid bars of Inconel X are required to absorb the heat energy.
https://history.nasa.gov/SP-60/ch-6.html
« Last Edit: 03/19/2017 02:19 pm by AncientU »
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