Author Topic: Q&A: Pegasus Designer Dr. Antonio Elias  (Read 149984 times)

Offline antonioe

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Re: Q&A: Pegasus Designer Dr. Antonio Elias
« Reply #380 on: 10/26/2007 03:07 AM »
O.K., O.K. white flag... I give up... how about "Taurus II XL - superAS"????
ARS LONGA, VITA BREVIS...

Offline simonbp

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Re: Q&A: Pegasus Designer Dr. Antonio Elias
« Reply #381 on: 10/27/2007 02:07 AM »
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Skyrocket - 25/10/2007  3:51 PM

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aero313 - 25/10/2007  11:31 PM
Ask your new Lockmart friends why every Martin Marietta launch vehicle was named "Titan".  

Just nitpicking: this launch vehicle must be a "Titan-2AS" (take a look at the company name)

It still applies; Atlas II was basically a completely new rocket, but they kept the same name they'd been using since 1951...

Simon ;)

Offline Jim

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Re: Q&A: Pegasus Designer Dr. Antonio Elias
« Reply #382 on: 10/27/2007 02:31 PM »
Not really.   It was Atlas III and V

Offline tnphysics

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Re: Q&A: Pegasus Designer Dr. Antonio Elias
« Reply #383 on: 10/27/2007 05:33 PM »
Could Cygnus have a flyback first stage? Will the third stage be used for all missions, or for high energy missions only?

Offline antonioe

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Re: Q&A: Pegasus Designer Dr. Antonio Elias
« Reply #384 on: 10/27/2007 06:36 PM »

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tnphysics - 27/10/2007 12:33 PM Could Cygnus have a flyback first stage? Will the third stage be used for all missions, or for high energy missions only?

No, no reuseability of any kind.  As I mentioned in previous pontifications, reuseability only pays off at a launch rate of 50-60 a year (for full reuseability).  We are talking 2 to 5 flights a year here, with luck!

No, expendables win hands down in this case...

There isn't a real "third stage" - the second stage has a big solid that gets separated, then a bipropellant low-thrust system takes over for orbital maneuvering, but it has way way less than 1/3 of the total ΔV capability of the stack (a "true" third stage would have about 1/3 of the total ΔV - on Cygnus, the combination of the solid and the biprop has about 1/2 of the total ΔV, so together they form kind of a second stage, except you DO stage the solid... sometimes the realities of what is available makes you do things different from "normal" designs...)

For missions where the accuracy of the final velocity of the orbital injection does not matter so much because "something else" (such as the the satellite's propulsion system) takes care of the precision, you can eliminate the biprop altogether.  A good example would be an escape (C3 >= 0) mission where a Star 48 replaces the biprop for an added "kick" to a much smaller payload.

For example, Cygnus is now showing a LEO payload in excess of 5,000 Kg, but only 1,000 Kg payload to C3=10 Km2/sec2, and this requires replacing the biprop with a Star 48.  Now, in THIS case the Star 48 DOES behave like a third stage (its ΔV is closer to being 1/3 of the total).

"Stagehood is in the eye of the bedesigner"

ARS LONGA, VITA BREVIS...

Offline tnphysics

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Re: Q&A: Pegasus Designer Dr. Antonio Elias
« Reply #385 on: 10/27/2007 07:14 PM »

Why not use the biprop for a large part of the delta-V? It has better performance than the solid.

The first stage providing half of the delta-V makes sense because it has the highest Isp.

What fraction of the delta-V does stage 3 currently provide?

Which hypergolic propellants are used by stage 3?

Funny line you created.  :laugh:


Offline tnphysics

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Re: Q&A: Pegasus Designer Dr. Antonio Elias
« Reply #386 on: 10/27/2007 07:25 PM »
What if you started to run out of NK-33 engines?

What is/will be the name of the stage engine? Is it new or not?

What is/will be the name of the stage 2 motor. Is it new?

Offline antonioe

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Re: Q&A: Pegasus Designer Dr. Antonio Elias
« Reply #387 on: 10/28/2007 01:23 PM »
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tnphysics - 27/10/2007 2:14 PM

Why not use the biprop for a large part of the delta-V? It has better performance than the solid.

We can't find a biprop with the thrust and duration needed to do that.

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The first stage providing half of the delta-V makes sense because it has the highest Isp.

The rule of thumb that sez "give the stage with the highest Isp most of the ΔV" works only for "rubber components", i.e., where you can arbitrarily specify the thrust, thrust duration, etc. of the propulsive units.  If you have to work with what's available, you have to break the rules of thumb.

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What fraction of the delta-V does stage 3 currently provide?

As I said before, we don't really have a true "Stage 3".  But if you are asking "what fraction of the ΔV does the biprop subsystem provide", the answer is: for low-altitude, high-payload missions, probably about 10%.  For higher-altitude, low-payload missions, more.

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Which hypergolic propellants are used by stage 3?

We are stealing that system from StarBus, so - N2O4 and Hydrazine;  that's what everybody tries to use these days...

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Funny line you created. :laugh:

Uh? Which one?  I try to create as many funny lines as I can (keeping mental sanity and all that, you know...)

ARS LONGA, VITA BREVIS...

Offline antonioe

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Re: Q&A: Pegasus Designer Dr. Antonio Elias
« Reply #388 on: 10/28/2007 01:38 PM »

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tnphysics - 27/10/2007 2:25 PM What if you started to run out of NK-33 engines

The question is not IF, but WHEN.  The answer is we start building them here in the good 'ol USA.  But we have a few years to get ready for that - if the 60 units or so run out in less than 10 years, we will be swimming in cash.  Reality is, it will take more than 10 years to go through 60 units (30 flights...) so we have plenty of time to get ready.

It may take as much money to qualify the US-built NK-33's as to develop Taurus II (not because qualifying US-build NK-33's costs a lot, but because we are developing Taurus II with very, VERY little money... about $150M)

So, in the spirit of "fund a little - develop a little (and wait for customers to buy a little)", we are waiting until we burn about 50% of the NK-33 inventory before funding THAT part. 

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 What is/will be the name of the stage engine? which stage? Is it new or not?

Which stage?  You mean the biprop?  It's a Japanese (IHI) unit... we use IHI biprops on all our StarBuses as the Apogee propulsion unit...

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What is/will be the name of the stage 2 motor. Is it new?

Yes, but it's being developed by somebody else, so I can't talk about it until the other party agrees we can do so...

ARS LONGA, VITA BREVIS...

Offline antonioe

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Re: Q&A: Pegasus Designer Dr. Antonio Elias
« Reply #389 on: 10/28/2007 02:08 PM »

Did I mention that Dan Tani, who is going to be "up there" for a while, worked several years at Orbital?  He worked on the Transfer Orbit Stage (TOS) and was our Test Conductor during the Mars Observer launch on Sep 25, 1992 (a day I remember very well - I was the Orbital senior at our control room at the Cape - I ate a whole jar of Planter's shelled peanuts while on-console and gained 5 lbs - aero313 was the Chief Engineer, if I remember correctly... Joe?).

The Titan 34D carrying M.O. atop our TOS was the FIRST launch from the newly-refurbished LC-40, sporting the world's heaviest structure to move on land (the Titan-IV sized, 6,000 tons Service Structure!!)  The service structure was so heavy, as a matter of fact, that its motion disturbed the alignement of the TOS IMU, almost causing a scrub!  Also, the Service Structure interfered with the umbilical tower, so the Martin-Marietta guys used a HYDRAULIC JACK to deform the unbilical tower in place!!!  The Titan 34D barely reached two-thirds of the way up...

That great behemoth is no more.  LC-40 was designed to launch a Titan "every 15 to 19 days"... today, with the great structure gone, LC-40 is a wasteland.

ARS LONGA, VITA BREVIS...

Offline Seer

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Re: Q&A: Pegasus Designer Dr. Antonio Elias
« Reply #390 on: 10/28/2007 07:12 PM »
Antonio, on a completely unrelated question ...do you think a leo broadband system, like Teledesic, will ever be deployed?
 Or have geo based systems won the day? (I would've thought that globalization would boost the case for leo systems.)


Also, would Orbital ever get into that business again - operating a constellation, like they did with Orbcomm?


Offline antonioe

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Re: Q&A: Pegasus Designer Dr. Antonio Elias
« Reply #391 on: 10/29/2007 02:45 AM »

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Seer - 28/10/2007 3:12 PM Antonio, on a completely unrelated question ...do you think a leo broadband system, like Teledesic, will ever be deployed? Or have geo based systems won the day? (I would've thought that globalization would boost the case for leo systems.)

Well, recent technical developments include dramatic lowering of the cost of extremely-high-frequency components (thank you, cell phones and WiFi), which could enable much tighter spot beams from "Up high", tilting the playing field towards Geos.  One of the arguments for, say, ORBCOMM was that LEOs allowed the use of smaller, lower frequency, lower power and cheaper user units.  That may not be valid any more (for example, the size of the ANTENNA now becomes a big factor!)

I think Thuraya is an example on how that thinking has changed.

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Also, would Orbital ever get into that business again - operating a constellation, like they did with Orbcomm?

I don't think so... I can see some Orbital people (even DWT!) leaving Orbital and starting a "spinoff" to do that, but not within the current financial structure... Wall Street abandoned our "dot com" image eight years ago (and rightly so!) so now we are, mostly "the pure play aerospace company that has the highest growth potential".

I can see, however, Orbital operating a constellation for somebody else!

ARS LONGA, VITA BREVIS...

Offline CFE

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Re: Q&A: Pegasus Designer Dr. Antonio Elias
« Reply #392 on: 10/30/2007 11:34 PM »
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antonioe - 28/10/2007  9:08 AM

That great behemoth is no more.  LC-40 was designed to launch a Titan "every 15 to 19 days"... today, with the great structure gone, LC-40 is a wasteland.

Now that SpaceX has the site, I hope they can have better luck.  They obviously requested it because it would be beefy enough to handle an F9 Heavy.

As far as Taurus-2 development costs are concerned, you can count me as being very impressed with the fiscal discipline being practiced at Orbital.  I saw a similar statement in Space News and thought that you guys had to be on to something if you've gone this far down the Taurus-2 development path.  Hopefully the "Taurus-2" moniker will die by this December if the program goes ahead.
"Black Zones" never stopped NASA from flying the shuttle.

Offline vt_hokie

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Re: Q&A: Pegasus Designer Dr. Antonio Elias
« Reply #393 on: 10/30/2007 11:46 PM »
While neither LEO nor GEO, Globalstar is apparently still chugging along and renewing its fleet.  I haven't followed it closely, and I certainly don't know where the money is coming from, but I guess there must be demand from somebody!

Offline antonioe

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Re: Q&A: Pegasus Designer Dr. Antonio Elias
« Reply #394 on: 10/31/2007 12:52 AM »

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CFE - 30/10/2007 7:34 PM

Hopefully the "Taurus-2" moniker will die by this December if the program goes ahead.

Amen, brother!!!  Problem is, it's starting to solidify faster than anybody thought...

ARS LONGA, VITA BREVIS...

Offline antonioe

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Re: Q&A: Pegasus Designer Dr. Antonio Elias
« Reply #395 on: 10/31/2007 12:55 AM »

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vt_hokie - 30/10/2007 7:46 PM While neither LEO nor GEO, Globalstar is apparently still chugging along and renewing its fleet. I haven't followed it closely, and I certainly don't know where the money is coming from, but I guess there must be demand from somebody!

Yeah... exactly what we are wondering... we're keeping an eye on Globalstar and even good 'ol Orbcomm, but it's hard to compete with the Ukranians... not to mention the up-and-coming Indians...

Indeed, I'm willing to bet a chocolate milkshake (G. David Low's favorite bet) that India will emerge as the leading low-cost international supplier of commercial launches.  They are technologically sophisticated, and their labor costs are low.  Can't beat that!

ARS LONGA, VITA BREVIS...

Offline antonioe

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Re: Q&A: Pegasus Designer Dr. Antonio Elias
« Reply #396 on: 10/31/2007 01:00 AM »

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CFE - 30/10/2007 7:34 PM As far as Taurus-2 development costs are concerned, you can count me as being very impressed with the fiscal discipline being practiced at Orbital. I saw a similar statement in Space News and thought that you guys had to be on to something if you've gone this far down the Taurus-2 development path.

Thanks for the kudos... the team will be pleased to know that somebody out there appreciates their efforts.  If we only had the RocketPlane Kistler money...

ARS LONGA, VITA BREVIS...

Offline CFE

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Re: Q&A: Pegasus Designer Dr. Antonio Elias
« Reply #397 on: 10/31/2007 01:22 AM »
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antonioe - 30/10/2007  7:52 PM

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CFE - 30/10/2007 7:34 PM

Hopefully the "Taurus-2" moniker will die by this December if the program goes ahead.

Amen, brother!!!  Problem is, it's starting to solidify faster than anybody thought...


Perhaps that could be fixed if somebody from Orbital gave an exclusive interview to "Space News" and used "Cygnus" instead.
"Black Zones" never stopped NASA from flying the shuttle.

Offline vt_hokie

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Re: Q&A: Pegasus Designer Dr. Antonio Elias
« Reply #398 on: 10/31/2007 02:22 AM »
Perhaps I misspoke - I guess Globalstar is considered "Low Earth Orbit" rather than "Medium Earth Orbit" at roughly 1400 km.


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antonioe - 30/10/2007  9:55 PM

Indeed, I'm willing to bet a chocolate milkshake (G. David Low's favorite bet) that India will emerge as the leading low-cost international supplier of commercial launches.  They are technologically sophisticated, and their labor costs are low.  Can't beat that!


Hard to argue, though I'd love to see the United States remain competitive in the commercial launch business! (Or should I say become competitive once again!)


Offline simonbp

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Re: Q&A: Pegasus Designer Dr. Antonio Elias
« Reply #399 on: 10/31/2007 03:00 AM »
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antonioe - 28/10/2007  7:38 AM

Yes, but it's {the second stage} being developed by somebody else, so I can't talk about it until the other party agrees we can do so...

For reference, is it in the similar total impulse range as a 48B, or larger?

Also, ~1000 kg to C3 means about ~350 kg to the lunar surface; should be enough for a Google rover... :)

Simon ;)

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