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Today's Antares launch just failed



 
 
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  #11  
Old October 30th 14, 09:37 PM posted to sci.space.station
David Spain[_4_]
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Posts: 314
Default Today's Antares launch just failed

On Wednesday, October 29, 2014 8:24:50 PM UTC-4, JF Mezei wrote:
NASA released a simgle image, aereal view of the launch pad.

http://www.nasa.gov/press/2014/octob.../#.VFF_5ee6BoU



There appears to be very little debris. Is this because NASA deliberatly
chose to release an image that has the real debris out of camera angle ?


Great picture.

I disagree. There seems to be a lot of debris, it's just that none of it is very big. Given the magnitude of the explosion, nor would I expect any of it to be. Check out the "bullet holes" in the water tower tank. (Can't really see if there was total penetration but something impacted there). They're going to be pulling fragments out of this site for awhile. You can also see what appears to be an impact crater just to the seaward side of the LC. *sigh* From the twisted metal perspective I suppose it could have been worse. Also don't forget of a fair amount of debris is no doubt hidden underwater.

Some spectacular corkscrewing in the exploding wreckage as I recall.

It's experiences like this (not scrubs) that *really* test the professionalism of your team, and put the "steely-eyed" into the missile-men and missile-women.

Pick-up, clean-up, fix, test, and try again... Ad Astra Orbital...

Dave
  #12  
Old October 30th 14, 11:59 PM posted to sci.space.station
Greg \(Strider\) Moore
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Posts: 752
Default Today's Antares launch just failed

"JF Mezei" wrote in message
eb.com...

On 14-10-29 23:03, Greg (Strider) Moore wrote:

Yeah. This is one of the lessons I think we CAN take from the shuttle
program. Reusability at the very least lets you gain experience with the
same engines and equipment.


What if disposable engines would recuperated and analysed post flight ?
Wouldn't that also give some valuable "how they behave in real life" to
help fine tune the design ?


Yes and no.

First what is a "disposable engine"? Think a bit about that before
replying. What makes an engine disposable?

Also, it won't eliminate infant mortality issues.

I believe, but don't have a cite handy, when they finally started reducing
the amount of teardowns they did on the SSMEs, reliability went up. (since
few places to introduce issues)

And also, how do you RECOVER said engine in a condition that it's fit to be
analyzed? And if you're going through that much trouble, why's it not
re-usable again?


--
Greg D. Moore http://greenmountainsoftware.wordpress.com/
CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net

  #13  
Old October 31st 14, 11:57 AM posted to sci.space.station
Greg \(Strider\) Moore
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Posts: 752
Default Today's Antares launch just failed

"JF Mezei" wrote in message
eb.com...

On 14-10-30 18:59, Greg (Strider) Moore wrote:


You completely avoided the most important question.

What defines a "disposable" engine and why?

That's a very important question.


Also, it won't eliminate infant mortality issues.


However, the "disposable" engines are tested prior to launch. NASA and
Obital repeated this many times that the particular engine on this
flight had been fully tested at Stennis prior to being accepted.

If those engines are tested properly before lauch ( and I believe test
fired at the pad too, but obviously not to full power), shouldn't that
eliminate infant mortality ?


I'm not sure about that. That's pretty rare (and as for obviously not to
full power, I don't believe the NK-33 is throttable, so that basically means
0% or 100% power nothing in between.)


Is it possible that those engines are rated for only x minutes of
operation, and testing at Stennis uses up those minutes which causes
some wear in the engine, some at launch time, the engines are already
beyond designed lifetime ?


So you're claiming the engineers can't do basic math and determine that
testing the engines exceeded their lifetime?


(Perhaps the Soviets tested them far less (or not at all) before flight,
yielding more reliable launches ?


Right, because the N-1 was such a successful launcher.

Considering that this design had never flown to space successfully before
Orbital did so on their first Antares flight, I don't think one can make
that case.



On the other hand, if after testing at Stennis, the engines are taken
apart and inspected, then all bets are off.


I believe, but don't have a cite handy, when they finally started
reducing
the amount of teardowns they did on the SSMEs, reliability went up.
(since
few places to introduce issues)


Yes, but this requires enough flights with full teardowns to obtain MTBF
numbers that then allow you know know how often you need to check
certain areas and replace certain parts due to wear.

Recovering a disposable engine after a real flight might show that the
engine was dangerously beyond wear limits so it would need to be
redesigned more robustly, or that it was well within the limits.

BTW, for rocket engines, what propells the turbopumps ? is there a
turbine just outside the combustion chamnber (like on jet engines) that
give the motor force to spin the turbopumps ? Or are they
electric/hydraulic/whatever driven ?


That varies on the engine.

With the NK-33, preburners drive the pumps (and they use LOX to cool stuff
which to the US is a bit unusual.)


--
Greg D. Moore http://greenmountainsoftware.wordpress.com/
CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net

  #14  
Old October 31st 14, 05:30 PM posted to sci.space.station
Greg \(Strider\) Moore
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Posts: 752
Default Today's Antares launch just failed

"JF Mezei" wrote in message
eb.com...

On 14-10-31 06:57, Greg (Strider) Moore wrote:

What defines a "disposable" engine and why?


One that they don't even bother recovering after flight (let alone re-use).


You've defined DISPOSED engines, not disposable.

The point I'm trying to get is that designing an engine to be disposable is
somewhat stupid.

You need to build an engine with a certain level of margins. You want to be
able to do a test-fire, perhaps a pad abort.

At some point the smart engineer will realize that making a disposable, but
reliable engine doesn’t save you much in times of design costs or usage
costs.

We've got to stop thinking about "disposable" engines.




I'm not sure about that. That's pretty rare (and as for obviously not to
full power, I don't believe the NK-33 is throttable, so that basically
means
0% or 100% power nothing in between.)


During launch, I heard 108% just before the failure. Is it possible the
Orbital modifications to all the control systems on those engines allow
for throttling ?


Possible, but unlikely. In general for a multi-stage rocket you don't gain
much with the additional complexity. The SSME had it because it went from
sea-level to orbit.

Off the top of my head, the only other throttlable main stage engine I can
think of is Merlin and that's only because they want to land the thing
again.

So you're claiming the engineers can't do basic math and determine that
testing the engines exceeded their lifetime?


Depends on how the lifetime is defined. Also, NASA may require the
engines to spend X minutes running at Stennis, so Orbital signed the
papers to qualify the engines for those X minutes + launch.


And again, I'm sure OSC did the math on this.


Do they **really** know what those engines were rated for when the
Soviets built them ?


I'm sure OSC knows what they've been told. And what the testing suggests.




--
Greg D. Moore http://greenmountainsoftware.wordpress.com/
CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net

  #15  
Old October 31st 14, 10:41 PM posted to sci.space.station
Greg \(Strider\) Moore
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Posts: 752
Default Today's Antares launch just failed

"JF Mezei" wrote in message
eb.com...

On 14-10-31 12:30, Greg (Strider) Moore wrote:

At some point the smart engineer will realize that making a disposable,
but
reliable engine doesn’t save you much in times of design costs or usage
costs.


For the engines, you are probably correct. At the powers/thrust
involved, any imperfection yields wear and tear that is fatal.


Ah, but one would argue that any imperfections that are fatal will be so
very early on in the program.

However,
the cost of recovering the engines may make the economics less
attractive when you consider you can only re-use the engine a certain
number of times, unless you get to something like an aircraft engine.


And that's exactly the point. We have to start thinking about them like
aircraft engines with extended meantimes between failure.

Design for success, not failure.


Anytime a launch is done near ocean, it means SALT WATER is involved in
recovering the engines for first or second stage. And SALT WATER is bad!


That is probably really ultimately the biggest single issue with recovery,
not the design itself.


At the end of the day, the Shuttle wasn't all that bad despite all the
criticism.


The Shuttle got a lot wrong, enough that it tends to overshadow what it got
right.

Frank Culbertson said that the failure costed them about $200 million
bucks. I am pretty sure that if the SHuttle had been operated
"commercially" instead of "by pork", they could have lowered the launch
costs to about 300 million.


Ultimately, two things killed the shuttle:
Massive overhead
Few flights

And both drove each other. The per cost flight of a shuttle was about $300M.
When you figure the price per pound, that's actually pretty damn good.
BUT, the overhead costs were damn high. They made the mistake (well it
wasn't a mistake, they knew what they were doing and had little choice given
the state of the art and the budget) of not designing it from the start for
the lowest possible turnaround.

Examples: LFBB, would have almost certainly ended up cheaper than SRBs (if
only to eliminate the requirement for two ships off-shore to recover the
booster) but would have cost a LOT more to develop.

Or work platforms and designing the orbiter itself for far easier
serviceability. Planned early on, but cost and mass limited it. Of course
they were huge on "mass to orbit overall". Musk is making the choice of
"cost to orbit". If you can only fly 1/2 the payload but costs you .49 as
much, you come out ahead.

Or replace the OMS/RCS pods with a non-hypergolic. Cheaper to service, cost
more up front, etc.

So yes, we already know from what was built it could have been cheaper to
fly.

Fortunately, Musk and others are learning the right lessons (perhaps the
most important one being design for cost up front).




--
Greg D. Moore http://greenmountainsoftware.wordpress.com/
CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net

  #16  
Old November 1st 14, 04:30 PM posted to sci.space.station
Jeff Findley[_6_]
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Posts: 2,307
Default Today's Antares launch just failed

In article om,
says...

On 14-10-30 18:59, Greg (Strider) Moore wrote:

Also, it won't eliminate infant mortality issues.


However, the "disposable" engines are tested prior to launch. NASA and
Obital repeated this many times that the particular engine on this
flight had been fully tested at Stennis prior to being accepted.

If those engines are tested properly before lauch ( and I believe test
fired at the pad too, but obviously not to full power), shouldn't that
eliminate infant mortality ?


Not really since the engine was never tested on an actual flight of the
launch vehicle. Every flight of an expendable is the vehicle's first
flight. Would you fly on a brand new passenger airliner who's brand new
engines were only tested one at a time on a test stand?


I believe, but don't have a cite handy, when they finally started reducing
the amount of teardowns they did on the SSMEs, reliability went up. (since
few places to introduce issues)


Yes, but this requires enough flights with full teardowns to obtain MTBF
numbers that then allow you know know how often you need to check
certain areas and replace certain parts due to wear.


Certainly. The more data, the better.

Recovering a disposable engine after a real flight might show that the
engine was dangerously beyond wear limits so it would need to be
redesigned more robustly, or that it was well within the limits.


Might, but if you recover them completely intact, what is stopping you
from reusing them? If they're not intact, how do you discern the
difference between damage caused by running the engine from damage
caused by shoddy recovery of an "expendable" engine?

BTW, for rocket engines, what propells the turbopumps ? is there a
turbine just outside the combustion chamnber (like on jet engines) that
give the motor force to spin the turbopumps ? Or are they
electric/hydraulic/whatever driven ?


You need to read up on this. It's not that hard. What you're asking
for is akin to asking how an internal combustion engine works in a car.

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer
  #17  
Old November 1st 14, 04:46 PM posted to sci.space.station
Jeff Findley[_6_]
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Posts: 2,307
Default Today's Antares launch just failed

In article ,
says...

Right, because the N-1 was such a successful launcher.

Considering that this design had never flown to space successfully before
Orbital did so on their first Antares flight, I don't think one can make
that case.


I've come to learn that one NK-33 was used successfully on the first
stage of the Soyuz "light" test flight a few years ago. But, Russia has
a plan to replace it with a more modern design derived from the RD-171,
which itself has its roots all the way back to the NK-33 and the NK-15
(the engine used on the failed N-1 test flights).

Soyuz 2-1v launches on Maiden Flight after long Road to the Launch
Pad, December 28, 2013
http://www.spaceflight101.com/soyuz-...st-launch.html

But Soyuz 2-1v flew later in 2013 than the Antares test flight, so
Orbital Sciences was indeed the first to use the NK-33 on a launch
vehicle successfully.

Antares Rocket Aces First Test Flight, APR 21, 2013
http://news.discovery.com/space/priv...ntares-rocket-
aces-first-test-flight-130421.htm

I'd not kept up with the Soyuz "light" launcher because it always seemed
it would never happen. The Russians seemed quite satisfied flying the
more familiar Soyuz first stage that dates all the way back to the
original Sputnik satellite launch.

Still, Soyuz "light" has only been test flown once so far. Rumor has it
that Orbital will switch to the same "modern" engine to be used on the
Soyuz "light" for its Antares first stage. In my mind, that's the right
way to go. The thought that they'd use large solids for a first stage
does not sit well with me.

I'd really like to see an end to large solids all together. They are
quite unsuitable for any sort of reusable launch vehicle, so it is my
feeling their days are numbered in the launch vehicle industry.

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer
  #18  
Old November 1st 14, 04:55 PM posted to sci.space.station
Jeff Findley[_6_]
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Posts: 2,307
Default Today's Antares launch just failed

In article om,
says...

On 14-10-31 06:57, Greg (Strider) Moore wrote:

What defines a "disposable" engine and why?


One that they don't even bother recovering after flight (let alone re-use).


Give that man a prize!

Liquid fueled rocket engines are, by their very nature, reusable.
Evidence of this is the "test firings" of even "disposable" liquid
fueled rocket engines. If you can fire one on a test stand then use it
on a launch vehicle, there is nothing fundamental which prevents you
from using it for multiple flights of a launch vehicle. Inspect them,
replace any "single use" items, and you can repeatedly use them until
key components start to wear out.

I'm not sure about that. That's pretty rare (and as for obviously not to
full power, I don't believe the NK-33 is throttable, so that basically means
0% or 100% power nothing in between.)


During launch, I heard 108% just before the failure. Is it possible the
Orbital modifications to all the control systems on those engines allow
for throttling ?


100% is typically the original design thrust. Any upgrades to the
engines which result in more thrust are later expressed as a percentage
that is greater than 100%. But, that does not necessarily mean an
engine is capable of throttling during flight. It was a p.i.t.a. to do
this with the staged combustion SSMEs, so I'd expect similar pain if one
was to do so with a staged combustion LOX/kerosene engine like the NK-
33.

So you're claiming the engineers can't do basic math and determine that
testing the engines exceeded their lifetime?


Depends on how the lifetime is defined. Also, NASA may require the
engines to spend X minutes running at Stennis, so Orbital signed the
papers to qualify the engines for those X minutes + launch.


NASA has little to do with any of this. The "commercial cargo" and
"commercial crew" programs have NASA doing some oversight, but it is the
contract winners who are calling all of the shots in terms of overall
design and implementation.

Do they **really** know what those engines were rated for when the
Soviets built them ?


Only insofar as the Russians have shared their data with Aerojet
Rockedyne, which is the subcontractor who refurbished and test fired the
NK-33 engines and gave them an "AJ" (Aerojet) designation. NASA has
little to do with this. Note these engines were originally going to be
used by Kistler Aerospace, but when that company folded, Aerojet
Rocketdyne had already done some modifications and several test firings.
So, they offered them up to Orbital as a relatively inexpensive way to
get Antares flying quickly.

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer
  #19  
Old November 1st 14, 05:06 PM posted to sci.space.station
Jeff Findley[_6_]
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Posts: 2,307
Default Today's Antares launch just failed

In article om,
says...

On 14-10-31 12:30, Greg (Strider) Moore wrote:

At some point the smart engineer will realize that making a disposable, but
reliable engine doesn?t save you much in times of design costs or usage
costs.


For the engines, you are probably correct. At the powers/thrust
involved, any imperfection yields wear and tear that is fatal. However,
the cost of recovering the engines may make the economics less
attractive when you consider you can only re-use the engine a certain
number of times, unless you get to something like an aircraft engine.


I'll bet the propulsion engineers at Orbital would rather have reused a
proven engine than playing Russian Roulette with "new" NK-33 engines on
each flight.

Anytime a launch is done near ocean, it means SALT WATER is
involved in recovering the engines for first or second stage.
And SALT WATER is bad!


So don't dunk your stage in salt water. There are solutions to the
problem which do just that.

At the end of the day, the Shuttle wasn't all that bad despite all the
criticism.


The major criticism was the abysmally low flight rate which led to
hideously high fixed costs per flight. This was because the design
required much refurbishment between flights. It wasn't a "gas and go"
design. But, we must give NASA some credit in that it did fly and did
so without completely blowing its development budget. It was the
operational costs that were the problem. They were so high, it
prevented full funding of a replacement until after the program was
terminated resulting in the current "gap" in US manned spaceflight that
has yet to be closed either by "commercial crew" (running on a quite
limited budget) or by SLS/Orion (running on what many would consider an
obscenely high billions of dollars per year budget).

Frank Culbertson said that the failure costed them about $200 million
bucks. I am pretty sure that if the SHuttle had been operated
"commercially" instead of "by pork", they could have lowered the launch
costs to about 300 million.


Bull****. The fixed costs were far too high. The flight rate would
have to be well into the dozens per year to obtain a cost that low.
That was never going to happen.

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer
  #20  
Old November 2nd 14, 07:22 PM posted to sci.space.station
Jeff Findley[_6_]
external usenet poster
 
Posts: 2,307
Default Today's Antares launch just failed

In article om,
says...

On 14-11-01 11:55, Jeff Findley wrote:

100% is typically the original design thrust. Any upgrades to the
engines which result in more thrust are later expressed as a percentage
that is greater than 100%. But, that does not necessarily mean an
engine is capable of throttling during flight.


So it means that at launch, the engine goes from 0 to full thrust (108%)
in no time at all ? Isn't that a huge amount of stress ?


I said no such thing. And yes, startup is often a delicate thing.
Because of this, some of the hardware to start the SSMEs was left on the
ground. This is one reason why "air starting" an SSME is an idea that
comes around periodically, but never pans out.

NASA has little to do with any of this. The "commercial cargo" and
"commercial crew" programs have NASA doing some oversight, but it is the
contract winners who are calling all of the shots in terms of overall
design and implementation.


But doesn't NASA set standards ? Since the craft takes off from a NASA
facility and docks to a NASA facility and carries cargo for NASA, I
suspect MASA has a lot of say in how everything is done.


Certainly there is oversight, but in "commercial cargo" and "commercial
crew", NASA doesn't necessarily dictate design decisions. The devil is
in the details, and they've generally left the details up to the
"commercial" half of the equation.

Only insofar as the Russians have shared their data with Aerojet
Rockedyne, which is the subcontractor who refurbished and test fired the
NK-33 engines and gave them an "AJ" (Aerojet) designation.


How many such engines did they get ? How many can they destructivelty
test to measure their tolerances ? I have to assume that since those
engines are from Soviet era, nobody would really trust the specs ?


Google is your friend. There is currently much talk about this in the
media, but you could start with the NK-33 wikipedia page and follow the
links from there.

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer
 




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