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Used, beaten up rockets gaining popularity !



 
 
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  #1  
Old November 6th 20, 07:26 PM posted to sci.space.policy
David Spain
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Default Used, beaten up rockets gaining popularity !

Snidely writes:

JF Mezei quipped:

I sure hope Boeing/Lockheed has some skunkworks developping re-usable
rocket ASAP.


A future Vulcan upgrade is the SMART package, for engine recovery with mid-air
snagging. See the wikiparticle.

/dps


This IS reusing the most expensive part of the rocket, however I don't
see how this competes with either at sea or RTLS landing of the entire
stage. Snagging the Vulcan engine assembly mid air will be a little more
complicated (quite doable just more complicated) and still requires
re-assembly of a new stage each time 'round. Once Starship is flying
this will also become an economic dog by comparison.

Dave
  #2  
Old November 6th 20, 07:37 PM posted to sci.space.policy
David Spain
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Default Used, beaten up rockets gaining popularity !

David Spain writes:
This IS reusing the most expensive part of the rocket, however I don't
see how this competes with either at sea or RTLS landing of the entire
stage. Snagging the Vulcan engine assembly mid air will be a little more
complicated (quite doable just more complicated)


Complicated compared to throwing the stage away I meant, not more
complicated than landing an entire stage! Sorry didn't make that too
clear.

Dave
  #3  
Old November 7th 20, 12:29 AM posted to sci.space.policy
snidely
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Default Used, beaten up rockets gaining popularity !

David Spain was thinking very hard :
Snidely writes:

JF Mezei quipped:

I sure hope Boeing/Lockheed has some skunkworks developping re-usable
rocket ASAP.


A future Vulcan upgrade is the SMART package, for engine recovery with
mid-air snagging. See the wikiparticle.

/dps


This IS reusing the most expensive part of the rocket, however I don't
see how this competes with either at sea or RTLS landing of the entire
stage. Snagging the Vulcan engine assembly mid air will be a little more
complicated (quite doable just more complicated) and still requires
re-assembly of a new stage each time 'round. Once Starship is flying
this will also become an economic dog by comparison.


Meanwhile, Rocket Lab is going to try chuting a whole first stage,
mid-November, a more definite date than anything ULA has mentioned.
First iteration is trying for a wet recovery, with helicopters
intervening on later launches.

/dps

--
"First thing in the morning, before I have coffee, I read the obits, If
I'm not in it, I'll have breakfast." -- Carl Reiner, to CBS News in
2015.
  #4  
Old November 7th 20, 02:28 PM posted to sci.space.policy
David Spain
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Posts: 2,901
Default Used, beaten up rockets gaining popularity !

JF Mezei writes:

On 2020-11-06 13:37, David Spain wrote:

Complicated compared to throwing the stage away I meant, not more
complicated than landing an entire stage! Sorry didn't make that too
clear.


How complicated would it be to make a delta IV, Arianne 5 or other
"legacy" rocket land?


Not difficult at all. Most of them already do. It's mainly a question of
velocity. :-)


Obviously, add legs, grid fins and software. But realistically, how
difficult is it to ignite main engines in flight during descent if they
don't have igniters on board?


Pretty difficult if there isn't someone on board with a match.

You'd need hypergolic propellants if you aren't using igniters.
Those present their own problems. Better off starting from scratch.
Of the legacy rockets, perhaps you could most easily retro fit a Titan
II. But the more I think about it, the more less it looks anything like
a Titan II.


If they want to catch Vulcan engines as they fall down, doesn't that
imply engine separation mechanism and likely parachutes for engines?

Wouldn't it be simpler to just have it land?


Nope. Since there's no propellant for it to combust. If it it's coming
down on chutes it's coming down fast enough to damage itself if it were
to make contact. I assume it's also not buoyant so that kinda rules out a
water landing. Sea water is notoriously bad for rockets engines anyway.
See:

https://spaceflightnow.com/2015/04/1...of-new-rocket/


Nice chart here that shows all.

Dave
  #5  
Old November 8th 20, 08:08 AM posted to sci.space.policy
snidely
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Default Used, beaten up rockets gaining popularity !

With a quizzical look, JF Mezei observed:
On 2020-11-07 08:28, David Spain wrote:

Pretty difficult if there isn't someone on board with a match.


Question remains: how difficult is it to put an igniter in an engine?
Since turbopump no not near the engine bells, igniting that "engine"
requires a spark generator that is already in there, doesn't it?

Do these rockets really requite sparks that are created by GSE? If so,
what it is mean when T reaches 0? The rocket sends command to ground
equipment to generate the sparks? What is so difficult about igniting
the engine from within?

Nope. Since there's no propellant for it to combust.


Surely, they can do like SpaceX, and return launchers where there is
spare fuel, and expand the ones that push the limits and have no fuel left?

What is so different with Falcon9 that allows it to ingnite its own
engines that nobody else can do?


Designed for restarts from the beginning. Most second stage engines
are also so designed, plus the shuttle main engines. I don't know if
SLS has retained that capability, but Wikipedia suggests that the RS-25
has it still ... dual-redundant spark igniters in the injectors of the
preburners.

Merlins start with a canister of ugly goops (TEA and TEB) that go
bezerk when mixed. Raptors use spark plugs to light torches that then
light the preburner and the main chamber.

Vulcan will use BE-4 engines, which are supposed to be restartable
during flight. Head pressure restarts the turbopumps, but WP doesn't
explain what igniters are used.

Blue Origin's demonstration of powered landings with the BE-3 engine
may have been too late in the Vulcan design cycle to give ULA
confidence in the approach. The BE-3U variant is going into the
Vulcan, though, as the upper stage. New Glenn will use the same
combination as Vulcan, it seems.

/dps

--
"That's a good sort of hectic, innit?"

" Very much so, and I'd recommend the haggis wontons."
-njm
  #6  
Old November 9th 20, 05:32 AM posted to sci.space.policy
Greg \(Strider\) Moore
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Posts: 752
Default Used, beaten up rockets gaining popularity !

"Snidely" wrote in message news:mn.3d6c7e4b28a58571.127094@snitoo...

With a quizzical look, JF Mezei observed:


What is so different with Falcon9 that allows it to ingnite its own
engines that nobody else can do?


Designed for restarts from the beginning. Most second stage engines are
also so designed, plus the shuttle main engines. I don't know if SLS has
retained that capability, but Wikipedia suggests that the RS-25 has it
still ... dual-redundant spark igniters in the injectors of the preburners.


The SSME were not designed to have relight capability. I don't know the
details, but a pad abort for example required them to do servicing.
Since there was no real reason for inflight reignition ability, my
understanding is they never put it in.

--
Greg D. Moore http://greenmountainsoftware.wordpress.com/
CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net
IT Disaster Response -
https://www.amazon.com/Disaster-Resp...dp/1484221834/

  #7  
Old November 9th 20, 08:40 AM posted to sci.space.policy
snidely
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Posts: 1,303
Default Used, beaten up rockets gaining popularity !

Lo, on the 11/8/2020, Greg (Strider) Moore did proclaim ...
"Snidely" wrote in message news:mn.3d6c7e4b28a58571.127094@snitoo...

With a quizzical look, JF Mezei observed:


What is so different with Falcon9 that allows it to ingnite its own
engines that nobody else can do?


Designed for restarts from the beginning. Most second stage engines are
also so designed, plus the shuttle main engines. I don't know if SLS has
retained that capability, but Wikipedia suggests that the RS-25 has it
still ... dual-redundant spark igniters in the injectors of the preburners.


The SSME were not designed to have relight capability. I don't know the
details, but a pad abort for example required them to do servicing.
Since there was no real reason for inflight reignition ability, my
understanding is they never put it in.


Ooops. Or OMS.

/dps

--
"This is all very fine, but let us not be carried away be excitement,
but ask calmly, how does this person feel about in in his cooler
moments next day, with six or seven thousand feet of snow and stuff on
top of him?"
_Roughing It_, Mark Twain.
  #8  
Old November 9th 20, 01:03 PM posted to sci.space.policy
Greg \(Strider\) Moore
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Posts: 752
Default Used, beaten up rockets gaining popularity !

"Snidely" wrote in message news:mn.458c7e4b01aa0c02.127094@snitoo...

Lo, on the 11/8/2020, Greg (Strider) Moore did proclaim ...
"Snidely" wrote in message news:mn.3d6c7e4b28a58571.127094@snitoo...

With a quizzical look, JF Mezei observed:


What is so different with Falcon9 that allows it to ingnite its own
engines that nobody else can do?

Designed for restarts from the beginning. Most second stage engines are
also so designed, plus the shuttle main engines. I don't know if SLS has
retained that capability, but Wikipedia suggests that the RS-25 has it
still ... dual-redundant spark igniters in the injectors of the
preburners.


The SSME were not designed to have relight capability. I don't know the
details, but a pad abort for example required them to do servicing.
Since there was no real reason for inflight reignition ability, my
understanding is they never put it in.


Ooops. Or OMS.


:-)



/dps


--
Greg D. Moore http://greenmountainsoftware.wordpress.com/
CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net
IT Disaster Response -
https://www.amazon.com/Disaster-Resp...dp/1484221834/

  #9  
Old November 9th 20, 03:44 PM posted to sci.space.policy
David Spain
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Posts: 2,901
Default Used, beaten up rockets gaining popularity !

JF Mezei writes:

On 2020-11-08 23:32, Greg (Strider) Moore wrote:

The SSME were not designed to have relight capability. I don't know the
details, but a pad abort for example required them to do servicing.
Since there was no real reason for inflight reignition ability, my
understanding is they never put it in.



In a previous message, it was alluded that some nasty chemicals used to
ignite engiunes (I assume hydrazyne, right?). Isn't it just a question
to grow the tank and have the pump disperse finite amount such that theu
can ignite 3 or 4 times during a flight?

It was TEA (tri-ethyl aluminum) and TEB (tri-ethyl boron).

https://en.wikipedia.org/wiki/Triethylborane


According to the Wikipedia page above this is used as an igniter for
both first and second stage for the SpaceX Falcon 9. But it is running
very different fuel from the Space Shuttle. I'm not sure you can just
inject this material into any old place on a LH2/LOX engine without it
going ka-boom. The shuttle igniters (on the ground) shot sparks into the
fuel flow POST mix at low rate. All key factors I'm sure.

Do they need heat to get fuel/oxydizez to has to ignite? Or can they
ignite either cold liquid H2 or Kerosene with liquid O2 with sparks?


I don't believe for SSME they are strictly liquid phase post
combination. My visual says a mostly a gaseous mixture at that point. So
the answer to your question is yes, at least partially.

If they need to pre-heat, how long are we talking about? less than a
second, a couple seconds? 1 minute ?


I'd guess it takes a second or so just based on the fuel flow, but
that's just speculation on my part.

Dave

  #10  
Old November 10th 20, 01:47 AM posted to sci.space.policy
David Spain
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Posts: 2,901
Default Used, beaten up rockets gaining popularity !

David Spain writes:

JF Mezei writes:

On 2020-11-08 23:32, Greg (Strider) Moore wrote:

The SSME were not designed to have relight capability. I don't know the
details, but a pad abort for example required them to do servicing.
Since there was no real reason for inflight reignition ability, my
understanding is they never put it in.



In a previous message, it was alluded that some nasty chemicals used to
ignite engiunes (I assume hydrazyne, right?). Isn't it just a question
to grow the tank and have the pump disperse finite amount such that theu
can ignite 3 or 4 times during a flight?


If you are interested in re-igniting a LH2/LOX engine go do a web search
on the Saturn V third stage. It had to light both for Earth orbital
injection as well as for Trans Lunar Injection.

https://en.wikipedia.org/wiki/Rocketdyne_J-2

The above answers the question: to wit: spark plugs, ullage and pre-chill.

Dave
 




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