RD-180 relplacement

I'm confused. The program to replace the RD-180 is focused on engines
with around 400,000 lb thrust at sea level. This focuses them on the
AR-1 (kerosene/LOC) and BE-4 (methane/LOX). Why are they not looking
at the RS-25 (LH2/LOX with similar thrust) or the Raptor engine
(methane/LOX)?

Seems like we're getting a lot of different engines when it might be
more efficient to settle on just a couple.


--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw

In article ,
says...

I'm confused. The program to replace the RD-180 is focused on engines
with around 400,000 lb thrust at sea level. This focuses them on the
AR-1 (kerosene/LOC) and BE-4 (methane/LOX). Why are they not looking
at the RS-25 (LH2/LOX with similar thrust) or the Raptor engine
(methane/LOX)?

RS-25 is hella expensive and ULA already knows that LH2/LOX produces a
large, expensive, vehicle (e.g. Delta IV). So that's right out since
Delta IV is already flying (no development costs there). But do note
that ULA really wants to ax Delta IV in favor of Atlas V due to its high
cost.

Raptor (methane/LOX) isn't "fully baked" yet (BE-4 is ahead of it).

Seems like we're getting a lot of different engines when it might be
more efficient to settle on just a couple.

AR-1 is a "backup" engine at this point since it's so far behind BE-4 in
both schedule and (estimated) per unit price. But, AR-1 is about the
right size for two of them to be a "drop-in" replacement for RD-180 on
Atlas V. So, if ULA stumbles on Vulcan, an AR-1 engined Atlas V might
be a good stop-gap measure.

At any rate, Aerojet Rocketdyne is being paid good money to develop AR-
1. Even if it meets the same fate as J-2X, they're getting money now
which helps keep the company alive.

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.

Jeff Findley wrote:

In article ,
says...

I'm confused. The program to replace the RD-180 is focused on engines
with around 400,000 lb thrust at sea level. This focuses them on the
AR-1 (kerosene/LOC) and BE-4 (methane/LOX). Why are they not looking
at the RS-25 (LH2/LOX with similar thrust) or the Raptor engine
(methane/LOX)?


RS-25 is hella expensive and ULA already knows that LH2/LOX produces a
large, expensive, vehicle (e.g. Delta IV). So that's right out since
Delta IV is already flying (no development costs there). But do note
that ULA really wants to ax Delta IV in favor of Atlas V due to its high
cost.


So why aren't they using something other than RS-25 on SLS?


Raptor (methane/LOX) isn't "fully baked" yet (BE-4 is ahead of it).


That sounds wrong to me. SpaceX test fired a full up Raptor engine
(albeit a lower thrust developmental engine) at their Texas facility
last year. The BE-4 has never been test fired and they didn't even
have a full engine put together until this year.



Seems like we're getting a lot of different engines when it might be
more efficient to settle on just a couple.


AR-1 is a "backup" engine at this point since it's so far behind BE-4 in
both schedule and (estimated) per unit price. But, AR-1 is about the
right size for two of them to be a "drop-in" replacement for RD-180 on
Atlas V. So, if ULA stumbles on Vulcan, an AR-1 engined Atlas V might
be a good stop-gap measure.


Aerojet Rocketdyne says they can start delivering AR1 engines in 2019,
so the finish line isn't all that far behind BE-4. Blue Origin says
the BE-4 will cost 60% of what an AR1 costs (at $12.5 million each);
so BE-4 engines are only around $7.5 million each? The government is
paying a lot of money to develop AR1, so I'd bet on it being pushed
for use somewhere. And AR1 does have the advantage of not needing a
bunch of new infrastructure to handle fueling and such.


At any rate, Aerojet Rocketdyne is being paid good money to develop AR-
1. Even if it meets the same fate as J-2X, they're getting money now
which helps keep the company alive.


How many billion dollars of taxpayer money are we going to spend
developing engines that never get used? Around $1.5 billion for AR1.
Around $1.2 billion for RS-25 (which only gets used if SLS keeps
flying). Another $1.2 billion for J-2X. Meanwhile Merlin engines
used on Falcon 9 cost around $1.2 million each with engines in the
Raptor/BE-4 class going for $7.5 million each? Meanwhile the entire
development budget for New Glenn is around $2.5 billion and what
little public data there is puts development costs for Raptor engines
in the hundreds of millions of dollars (vice billions) and I expect
BE-4 development is similar. What that says is that private companies
developing engines mostly on their own nickel is looking to be an
order of magnitude cheaper than traditional contracted engine
development programs...


--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw

On Wednesday, May 10, 2017 at 5:30:17 AM UTC-4, Fred J. McCall wrote:
Jeff Findley wrote:

In article ,
says...

I'm confused. The program to replace the RD-180 is focused on engines
with around 400,000 lb thrust at sea level. This focuses them on the
AR-1 (kerosene/LOC) and BE-4 (methane/LOX). Why are they not looking
at the RS-25 (LH2/LOX with similar thrust) or the Raptor engine
(methane/LOX)?


RS-25 is hella expensive and ULA already knows that LH2/LOX produces a
large, expensive, vehicle (e.g. Delta IV). So that's right out since
Delta IV is already flying (no development costs there). But do note
that ULA really wants to ax Delta IV in favor of Atlas V due to its high
cost.

So why aren't they using something other than RS-25 on SLS?

Raptor (methane/LOX) isn't "fully baked" yet (BE-4 is ahead of it).

That sounds wrong to me. SpaceX test fired a full up Raptor engine
(albeit a lower thrust developmental engine) at their Texas facility
last year. The BE-4 has never been test fired and they didn't even
have a full engine put together until this year.

Seems like we're getting a lot of different engines when it might be
more efficient to settle on just a couple.

AR-1 is a "backup" engine at this point since it's so far behind BE-4 in
both schedule and (estimated) per unit price. But, AR-1 is about the
right size for two of them to be a "drop-in" replacement for RD-180 on
Atlas V. So, if ULA stumbles on Vulcan, an AR-1 engined Atlas V might
be a good stop-gap measure.


Aerojet Rocketdyne says they can start delivering AR1 engines in 2019,
so the finish line isn't all that far behind BE-4. Blue Origin says
the BE-4 will cost 60% of what an AR1 costs (at $12.5 million each);
so BE-4 engines are only around $7.5 million each? The government is
paying a lot of money to develop AR1, so I'd bet on it being pushed
for use somewhere. And AR1 does have the advantage of not needing a
bunch of new infrastructure to handle fueling and such.

Three separate heavy lift vehicles in development that
would be capable of taking men to the Moon or Mars.

I don't really understand that. Last time one vehicle was
developed and they built 16 of them and had programs in
place to use them within a reasonable period of time, that
provided economies of scale and focus to do the program.
It was a national scale program and accomplished great
things.

The current approach doesn't make sense; too many vehicle
types in development and no real focus toward building
enough of them to have an actual program.

"Scott M. Kozel" wrote:

On Wednesday, May 10, 2017 at 5:30:17 AM UTC-4, Fred J. McCall wrote:
Jeff Findley wrote:

In article ,
says...

I'm confused. The program to replace the RD-180 is focused on engines
with around 400,000 lb thrust at sea level. This focuses them on the
AR-1 (kerosene/LOC) and BE-4 (methane/LOX). Why are they not looking
at the RS-25 (LH2/LOX with similar thrust) or the Raptor engine
(methane/LOX)?


RS-25 is hella expensive and ULA already knows that LH2/LOX produces a
large, expensive, vehicle (e.g. Delta IV). So that's right out since
Delta IV is already flying (no development costs there). But do note
that ULA really wants to ax Delta IV in favor of Atlas V due to its high
cost.

So why aren't they using something other than RS-25 on SLS?

Raptor (methane/LOX) isn't "fully baked" yet (BE-4 is ahead of it).

That sounds wrong to me. SpaceX test fired a full up Raptor engine
(albeit a lower thrust developmental engine) at their Texas facility
last year. The BE-4 has never been test fired and they didn't even
have a full engine put together until this year.

Seems like we're getting a lot of different engines when it might be
more efficient to settle on just a couple.

AR-1 is a "backup" engine at this point since it's so far behind BE-4 in
both schedule and (estimated) per unit price. But, AR-1 is about the
right size for two of them to be a "drop-in" replacement for RD-180 on
Atlas V. So, if ULA stumbles on Vulcan, an AR-1 engined Atlas V might
be a good stop-gap measure.


Aerojet Rocketdyne says they can start delivering AR1 engines in 2019,
so the finish line isn't all that far behind BE-4. Blue Origin says
the BE-4 will cost 60% of what an AR1 costs (at $12.5 million each);
so BE-4 engines are only around $7.5 million each? The government is
paying a lot of money to develop AR1, so I'd bet on it being pushed
for use somewhere. And AR1 does have the advantage of not needing a
bunch of new infrastructure to handle fueling and such.


Three separate heavy lift vehicles in development that
would be capable of taking men to the Moon or Mars.


Actually only one 'program'. And two commercial efforts.


I don't really understand that. Last time one vehicle was
developed and they built 16 of them and had programs in
place to use them within a reasonable period of time, that
provided economies of scale and focus to do the program.
It was a national scale program and accomplished great
things.


Last time we had a single government program that spent money like
water, made the trip, and then had no follow-on, which is why we can't
get beyond LEO anymore.


The current approach doesn't make sense; too many vehicle
types in development and no real focus toward building
enough of them to have an actual program.


The 'government program' (how we did Apollo) is the high priced
spread. It's true that it makes no sense because it has no real goal
(it changes with every President) and is too expensive to fly. The
other two efforts are commercial efforts, make more sense, spend a lot
less money, and will be far cheaper to fly.

If we did it the old way, we would ONLY have SLS, Musk and Bezos would
keep their money, and we'd get another 'flags and footprints' mission
to somewhere at best.


--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw

On Thursday, May 11, 2017 at 8:42:25 AM UTC-4, Fred J. McCall wrote:

"Scott M. Kozel" wrote:

Three separate heavy lift vehicles in development that
would be capable of taking men to the Moon or Mars.

Actually only one 'program'. And two commercial efforts.

I don't really understand that. Last time one vehicle was
developed and they built 16 of them and had programs in
place to use them within a reasonable period of time, that
provided economies of scale and focus to do the program.
It was a national scale program and accomplished great
things.

Last time we had a single government program that spent money like
water, made the trip, and then had no follow-on, which is why we can't
get beyond LEO anymore.

The current approach doesn't make sense; too many vehicle
types in development and no real focus toward building
enough of them to have an actual program.

The 'government program' (how we did Apollo) is the high priced
spread. It's true that it makes no sense because it has no real goal
(it changes with every President) and is too expensive to fly. The
other two efforts are commercial efforts, make more sense, spend a lot
less money, and will be far cheaper to fly.

If we did it the old way, we would ONLY have SLS, Musk and Bezos would
keep their money, and we'd get another 'flags and footprints' mission
to somewhere at best.

What kind of commercial effort for such a vehicle and program
could provide the tens of billions of dollars in private capital
to fund it? What would be the business model?

The federal government could provide 60-80% of the funding, but
that would not be a private sector effort, that would be massive
subsidization by the government.

Sure Apollo was expensive, but I wonder how the private sector
could profitably fund a program like that.

In article ,
says...

Jeff Findley wrote:

In article ,
says...

I'm confused. The program to replace the RD-180 is focused on engines
with around 400,000 lb thrust at sea level. This focuses them on the
AR-1 (kerosene/LOC) and BE-4 (methane/LOX). Why are they not looking
at the RS-25 (LH2/LOX with similar thrust) or the Raptor engine
(methane/LOX)?


RS-25 is hella expensive and ULA already knows that LH2/LOX produces a
large, expensive, vehicle (e.g. Delta IV). So that's right out since
Delta IV is already flying (no development costs there). But do note
that ULA really wants to ax Delta IV in favor of Atlas V due to its high
cost.


So why aren't they using something other than RS-25 on SLS?

Because the cheaper RS-68, used on Delta IV, isn't regeneratively cooled
and can't handle the heating environment at the base of the core stage
caused by both the main engines and the SRBs. This was discovered early
on in Ares V development, which planned on using the much cheaper RS-68.

In general, Ares V/SLS is a giant cluster *&^# of a program. If it ever
does fly it will be the biggest, most expensive, lowest flight rate
launch vehicle in history.


Raptor (methane/LOX) isn't "fully baked" yet (BE-4 is ahead of it).


That sounds wrong to me. SpaceX test fired a full up Raptor engine
(albeit a lower thrust developmental engine) at their Texas facility
last year. The BE-4 has never been test fired and they didn't even
have a full engine put together until this year.

I should say it's my opinion that Raptor is behind BE-4. Since both
companies are private and somewhat secretive, good information is hard
to come by. But from what's been reported in the press, Blue Origin has
a full size complete BE-4 development engine built and is getting ready
to test fire it. SpaceX could be at that point too but all I've heard
so far is that they've fired a lower thrust development engine, which
indicates they're not quite ready for full scale testing. Blue Origin,
on the other hand, thinks BE-4 is ready for "full scale" testing.

But the proof will be on the test stand, will it not?


Seems like we're getting a lot of different engines when it might be
more efficient to settle on just a couple.


AR-1 is a "backup" engine at this point since it's so far behind BE-4 in
both schedule and (estimated) per unit price. But, AR-1 is about the
right size for two of them to be a "drop-in" replacement for RD-180 on
Atlas V. So, if ULA stumbles on Vulcan, an AR-1 engined Atlas V might
be a good stop-gap measure.


Aerojet Rocketdyne says they can start delivering AR1 engines in 2019,
so the finish line isn't all that far behind BE-4. Blue Origin says
the BE-4 will cost 60% of what an AR1 costs (at $12.5 million each);
so BE-4 engines are only around $7.5 million each? The government is
paying a lot of money to develop AR1, so I'd bet on it being pushed
for use somewhere. And AR1 does have the advantage of not needing a
bunch of new infrastructure to handle fueling and such.

ULA is more worried about the per flight cost down the road. If they
have to install liquid methane tanks and plumbing, they'll do it to
lower costs. SpaceX is already undercutting *everyone* on launch costs
and that's without taking reuse into account. ULA is desperate to stay
alive at this point with SpaceX eating into its DOD launches that it
used to have a monopoly on.


At any rate, Aerojet Rocketdyne is being paid good money to develop AR-
1. Even if it meets the same fate as J-2X, they're getting money now
which helps keep the company alive.


How many billion dollars of taxpayer money are we going to spend
developing engines that never get used? Around $1.5 billion for AR1.
Around $1.2 billion for RS-25 (which only gets used if SLS keeps
flying). Another $1.2 billion for J-2X. Meanwhile Merlin engines
used on Falcon 9 cost around $1.2 million each with engines in the
Raptor/BE-4 class going for $7.5 million each? Meanwhile the entire
development budget for New Glenn is around $2.5 billion and what
little public data there is puts development costs for Raptor engines
in the hundreds of millions of dollars (vice billions) and I expect
BE-4 development is similar. What that says is that private companies
developing engines mostly on their own nickel is looking to be an
order of magnitude cheaper than traditional contracted engine
development programs...



Maybe the US Government should get out of the game of funding
development of engines and launch vehicles. SpaceX and Blue Origin have
both proven that private industry can do this themselves, with
sufficient funding.

AJR sat on its ass for how long after RD-180 was picked for Atlas?
They've known for *decades* that the US needed a high thrust
LOX/kerosene engine to remain competitive in the global launch market
and they literally sat on their hands waiting for a government handout
to start development. AJR deserves to go under at this point. It's
management is wholly dependent on old style cost-plus contracts. They
don't know how to innovate. They don't know how to compete on cost.

NASA and DOD need to switch their space support back to the same style
of support that NACA used to give to aircraft and (jet) engine
manufacturers in the US. NACA didn't design and build commercial
engines or aircraft. And NACA certainly didn't operate its own
airlines. It's well past time for the US Government to get the hell out
of the launch business and let good old fashioned capitalism and market
based competition sort out the cheapest way to orbit.

This is the kind of **** that the "crazy" people on the old sci.space
argued for back in the early 1990s when they were pushing CATS (cheap
access to space). It's now been over 30 years since then, and SpaceX
has proven them right. The government needs to get the *&%# out of the
way and support the commercial providers rather than building yet
another Government Luanch System which will be a drain on NASA's budget
for decades to come.

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.

Jeff Findley wrote:

In article ,
says...

Jeff Findley wrote:

In article ,
says...

I'm confused. The program to replace the RD-180 is focused on engines
with around 400,000 lb thrust at sea level. This focuses them on the
AR-1 (kerosene/LOC) and BE-4 (methane/LOX). Why are they not looking
at the RS-25 (LH2/LOX with similar thrust) or the Raptor engine
(methane/LOX)?


RS-25 is hella expensive and ULA already knows that LH2/LOX produces a
large, expensive, vehicle (e.g. Delta IV). So that's right out since
Delta IV is already flying (no development costs there). But do note
that ULA really wants to ax Delta IV in favor of Atlas V due to its high
cost.


So why aren't they using something other than RS-25 on SLS?


Because the cheaper RS-68, used on Delta IV, isn't regeneratively cooled
and can't handle the heating environment at the base of the core stage
caused by both the main engines and the SRBs. This was discovered early
on in Ares V development, which planned on using the much cheaper RS-68.

In general, Ares V/SLS is a giant cluster *&^# of a program. If it ever
does fly it will be the biggest, most expensive, lowest flight rate
launch vehicle in history.


I'm inclined to say that RS-25 'won' the studies because it got extra
points for being 'Shuttle-derived', which was a stupid requirement in
the first place.


Raptor (methane/LOX) isn't "fully baked" yet (BE-4 is ahead of it).


That sounds wrong to me. SpaceX test fired a full up Raptor engine
(albeit a lower thrust developmental engine) at their Texas facility
last year. The BE-4 has never been test fired and they didn't even
have a full engine put together until this year.


I should say it's my opinion that Raptor is behind BE-4. Since both
companies are private and somewhat secretive, good information is hard
to come by. But from what's been reported in the press, Blue Origin has
a full size complete BE-4 development engine built and is getting ready
to test fire it. SpaceX could be at that point too but all I've heard
so far is that they've fired a lower thrust development engine, which
indicates they're not quite ready for full scale testing. Blue Origin,
on the other hand, thinks BE-4 is ready for "full scale" testing.

But the proof will be on the test stand, will it not?


Blue Origin says BE-4 will be ready for delivery this year (or they
did; not sure if that's still their story now). Blue Origin has more
schedule pressure for this class engine than SpaceX does, since they
want it picked up by ULA for the engine for Vulcan (2020-2021 launch
dates) and the big thing they're touting is that it will be available
sooner than AR-1, which is the alternative engine. That being said,
BE-4 has apparently moved right at least some number of months, since
originally the full up engine tests were supposed to start last year
but they've only just got complete engines built. Meanwhile, SpaceX
has no real schedule driver for Raptor other than internal (ITS 2024
or so, which could easily move right) and their real priority
development right now is Falcon Heavy.


Seems like we're getting a lot of different engines when it might be
more efficient to settle on just a couple.


AR-1 is a "backup" engine at this point since it's so far behind BE-4 in
both schedule and (estimated) per unit price. But, AR-1 is about the
right size for two of them to be a "drop-in" replacement for RD-180 on
Atlas V. So, if ULA stumbles on Vulcan, an AR-1 engined Atlas V might
be a good stop-gap measure.


Aerojet Rocketdyne says they can start delivering AR1 engines in 2019,
so the finish line isn't all that far behind BE-4. Blue Origin says
the BE-4 will cost 60% of what an AR1 costs (at $12.5 million each);
so BE-4 engines are only around $7.5 million each? The government is
paying a lot of money to develop AR1, so I'd bet on it being pushed
for use somewhere. And AR1 does have the advantage of not needing a
bunch of new infrastructure to handle fueling and such.

ULA is more worried about the per flight cost down the road. If they
have to install liquid methane tanks and plumbing, they'll do it to
lower costs. SpaceX is already undercutting *everyone* on launch costs
and that's without taking reuse into account. ULA is desperate to stay
alive at this point with SpaceX eating into its DOD launches that it
used to have a monopoly on.


ULA is saying that base Raptor (with no solids) will cost around $100
million per launch. That gets you around 10 tonnes to LEO. Current
Falcon 9 has double the payload and is only 2/3 the cost, which makes
it about 1/3 the cost per pound. So ULA's new best effort at economy
still costs 3x what the competition costs.


At any rate, Aerojet Rocketdyne is being paid good money to develop AR-
1. Even if it meets the same fate as J-2X, they're getting money now
which helps keep the company alive.


How many billion dollars of taxpayer money are we going to spend
developing engines that never get used? Around $1.5 billion for AR1.
Around $1.2 billion for RS-25 (which only gets used if SLS keeps
flying). Another $1.2 billion for J-2X. Meanwhile Merlin engines
used on Falcon 9 cost around $1.2 million each with engines in the
Raptor/BE-4 class going for $7.5 million each? Meanwhile the entire
development budget for New Glenn is around $2.5 billion and what
little public data there is puts development costs for Raptor engines
in the hundreds of millions of dollars (vice billions) and I expect
BE-4 development is similar. What that says is that private companies
developing engines mostly on their own nickel is looking to be an
order of magnitude cheaper than traditional contracted engine
development programs...


Maybe the US Government should get out of the game of funding
development of engines and launch vehicles. SpaceX and Blue Origin have
both proven that private industry can do this themselves, with
sufficient funding.


USAF has (mostly) gone this direction. NASA hasn't. What NASA needs
to do is put together performance requirements specs for what they
want and then be flexible about trading away requirements for schedule
and dollars to commercial vendors. Along the lines of "You want X, Y,
and Z. We can give you X and Y in A years for B money, but Z will
double the cost and schedule. How badly do you need Z?"


AJR sat on its ass for how long after RD-180 was picked for Atlas?
They've known for *decades* that the US needed a high thrust
LOX/kerosene engine to remain competitive in the global launch market
and they literally sat on their hands waiting for a government handout
to start development. AJR deserves to go under at this point. It's
management is wholly dependent on old style cost-plus contracts. They
don't know how to innovate. They don't know how to compete on cost.


Yep. But they've been burned before on developing engines and not
being able to sell them after, so I can kind of understand why they
would risk a billion of their own money. Since they don't make
vehicles, engine development is riskier for them.


NASA and DOD need to switch their space support back to the same style
of support that NACA used to give to aircraft and (jet) engine
manufacturers in the US. NACA didn't design and build commercial
engines or aircraft. And NACA certainly didn't operate its own
airlines. It's well past time for the US Government to get the hell out
of the launch business and let good old fashioned capitalism and market
based competition sort out the cheapest way to orbit.


Yep, it's past time for this change. For what they're spending on
SLS/Orion development NASA could have pretty much funded the total
development of both ITS from SpaceX and New Glenn from Blue Origin and
had change left.


This is the kind of **** that the "crazy" people on the old sci.space
argued for back in the early 1990s when they were pushing CATS (cheap
access to space). It's now been over 30 years since then, and SpaceX
has proven them right. The government needs to get the *&%# out of the
way and support the commercial providers rather than building yet
another Government Luanch System which will be a drain on NASA's budget
for decades to come.


Yep, I remember that. Even back then people were saying 'performance
uber alles' was the wrong approach and proposing things like 'big dumb
boosters' and accepting the addition weight of using swaged steel
rather than aluminum because of the cost advantage. But it kind of
took Elon Musk to find the right path to cheaper launches.


--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw

In article ,
says...

This is the kind of **** that the "crazy" people on the old sci.space
argued for back in the early 1990s when they were pushing CATS (cheap
access to space). It's now been over 30 years since then, and SpaceX
has proven them right. The government needs to get the *&%# out of the
way and support the commercial providers rather than building yet
another Government Luanch System which will be a drain on NASA's budget
for decades to come.


Yep, I remember that. Even back then people were saying 'performance
uber alles' was the wrong approach and proposing things like 'big dumb
boosters' and accepting the addition weight of using swaged steel
rather than aluminum because of the cost advantage. But it kind of
took Elon Musk to find the right path to cheaper launches.


There was the "big dumb booster" crowd, but there was also the reusable
SSTO crowd and the reusable TSTO crowd. And there were also out of the
box ideas like POGO which would have been a reusable turbojet powered
first stage for a reusable near SSTO. There were even people who pushed
"modular" rockets like OTRAG since the modules could be mass produced
which would lower costs.

Lots and lots of ideas, but precious little funding in a world where
NASA had all the "experts" and many of the "experts" didn't think anyone
but NASA could innovate. It was also a time when DOD was funding two
EELVs and you'd have to compete with those as well. The bottom line was
that private investors were largely scared away because they didn't want
to compete with the US Government.

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.

To know the kind of engine you need, you need to know the vehicle it will be used for.

To know the kind of vehicle you need, you need to know where it is going and what the vehicle is used for.

To know where you are going and what you are doing, you have to have a long-term plan.

Is anyone doing this?

NASA is not - not officially.

China is - officially.

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Chinese Engines

YF-77 (165,000 lbf)
http://aviationweek.com/awin/chinese...xceed-saturn-v


Chinese Vehicles

Long-March 11 (140,000 lb LEO)
http://www.americaspace.com/2012/07/...g-new-rockets/

Chinese Missions

Mars
http://en.people.cn/200705/22/eng20070522_376754.html

Solar Power Satellite
http://news.xinhuanet.com/english/20..._134109115.htm

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A 140,000 lb payload to orbit, built with a common core and two outboard stages - all to the same design. Five Y-77 engines on each.

So, three modules each the same size and weight is about 1/2 the size of a Space Shuttle External Tank, with FIVE Y-77 engines at the base of each.

Each module;

316 tonnes module weight

36 tonnes structure weight Structure
43 tonnes LH2
237 tonnes LOX
77 Y-77 Engine Thrust
5 Number of Engines
1.218 Gees at lift off.

So, theres a core, and two outboard tanks, equipped with cross feeding, drain the two outboard tanks first and blast off with 15 Y-77 engines. When the two outboard tanks are drained they are dropped and fly back to the launch centre after boosting the system to 2.2 km/sec.

The central core adds another 5.8 km/sec to attain orbit with 63.6 tonnes payload. The central core re-enters, and returns to the launch centre.

* * *

Reaching for 400,000 lbs.

Expanding to 7 common core boosters with five Y-77 engines - raises the weight higher.

A seven element launcher puts up 182.0 tonnes payload (400,000 lbs) with four elements dropping off and flying back to the launch centre after adding 1.5 km/sec. The three element system continues as the second stage. The two elements dropping off after taking the vehicle up to 4.3 km/sec. Then finally the core element takes 182 metric tons to LEO. All fly back to be reused.

* * *

What to do when you get to orbit -

Interplanetary Stages - Nuclear thermal stage -

One interesting detail is the development of ceramic coated pellets of uranium that contain liquid uranium under supreme heating achieving 1600 sec Isp (15.68 km/sec Ve) using liquid hydrogen. This is an old idea, going back to the 1960s;

https://books.google.co.nz/books?id=...XGA9cQ6AEIJTAA

A 4000 MW thermal nuclear rocket the size of NERVA, operating at this level, produces 52.0 metric tons of thrust. The advantage of this system 182 metric ton payload can deliver a lot more across the solar system than chemical rockets!

https://www.lanl.gov/science/NSS/iss...ory4full.shtml

Nuclear Electric Stage

The nuclear thermal source is also used as a power supply using a closed Brayton cycle process. This produces 2000 MW electrical, from a 4000 MW thermal source which when used in an advanced ion engine that produces 54 km/sec exhaust speed (5500 sec Isp) produces 7.5 tonnes of thrust providing even greater payload fractions to Mars and beyond, and mass only 1.5 tonnes.

On board Nuclear Electric & Nuclear Electric on Mars

A nuclear thermal source will be used as a power supply to power the ship, the same way the nuclear power plant on a nuclear sub is used. The nuclear thermal source will be used as a power supply after landing. To power a lunar or mars or other planetary city. Including industrial processes that produce chemical fuels on Mars for boosters.

http://emits.sso.esa.int/emits-doc/E...33-SoW-RD1.pdf

For all these reasons, anyone serous about deep space manned travel will develop nuclear rocketry.

The PR angle

The technology is different enough from existing power plant designs, that they can be incorporated in advanced high temperature reactors on Earth, and the high profile nature of the successful missions they enable, are sufficient to promote their high technology, high reliability and high safety. A definite coup. Something the Chinese would exploit mid 21st century to sell compact high efficiency flexible power plants to cities and nations around the world struggling in a post oil future.

https://www.gen-4.org/gif/jcms/c_9362/vhtr

The radiation angle

What about radiation? Well, Cosmic Background Radiation and Solar radiation outside vanAllen belts of Earth, are definite safety hazards as well. The shielding required of a nuclear source could also shield astronauts aboard ship. A shadow shield has long been promoted as a 'safe haven' or 'storm shelter' or even a 'sun shield' for manned interplanetary missions. Another is to use powerful electro magnet and surplus electrical power to make a mini-magnetic shield around the ship.

https://home.cern/about/updates/2015...eld-astronauts

* * *

It takes 3.6 km/sec to exit LEO and head for Mars along a Hohmann Transfer Orbit. So, propellant fractions are;

Chemical
u = 1 - 1/exp(3.6/4.3) = 0.557 -- 39,930 lbs useful of 140,000 lbs, 114,100 lbs useful of 400,000 lbs

Nuclear Thermal
u = 1 - 1/exp(3.6/15.68) = 0.200 -- 98,970 lbs useful of 140,000 lbs, 282,770 lbs useful of 400,000 lbs

Nuclear Electric
u = 1 - 1/exp(3.6/54) = 0.063 -- 118.190 lbs useful of 140,000 lbs, 337,700 lbs useful of 400,000 lbs


A nuclear thermal rocket powered stage delivers 2.48x what a chemical stage delivers.
A nuclear electric rocket powered stage delivers 2.96x what a chemical stage delivers.

Now, a nuclear electric power source has a lot of other uses as well! So, a nuclear electric source, built around a nuclear thermal rocket, is a reasonable add-on to a nuclear thermal rocket programme.

If you're going to send large numbers of payloads across the solar system, you can do it more cheaply with the right engines, and nuclear rockets are the right engines.

* * *

Now this uses 1950s era technologies, updated slightly for today. Something the Chinese would feel comfortable doing as part of an integrated programme.

https://www.google.co.nz/url?sa=t&rc...e4ZL10FXWssogw

So, despite the small size of the Chinese Space Budget about 1/10th the size of NASA, in combination with support from the Chinese nuclear weapons and power programmes, a credible effort is being sustained along the lines described here.