Author Topic: Taurus II vs Atlas V for manned launch vehicle  (Read 36398 times)

Offline hop

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Re: Taurus II vs Atlas V for manned launch vehicle
« Reply #20 on: 07/28/2010 10:00 PM »
1) Can NK-33/AJ-26 be built in the US rather than the Ukraine? Even if it is still a foreign design, construction, testing and integration in the US will make a lot of people happier.
Aerojet has the rights to US production, but it's unlikely the economic case would close compared to restarting production in Russia. (As Ed says, it is not and never was Ukrainian. It also hasn't been produced since the Soviets canceled the N1 in the 70s)

If the government were going to pay for US production of a Russian engine, it might be better to bite the bullet and do the RD-180 (for which US production rights also exists.)

Online ugordan

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Re: Taurus II vs Atlas V for manned launch vehicle
« Reply #21 on: 07/28/2010 10:02 PM »
But it seems that the Russian high-pressure kerolox staged combusion, in multiple thrust classes (and even staged-combustion hypergolics) are not so bad after all. Kerosene -- of all substances! -- is apparently coming back, partly because cost is now more important than performance, and because we can leverage past Russian and Soviet investments.

For commercial purposes - LEO and GTO it might be most cost-effective. For really high energy missions I probably wouldn't count LH2 out just yet.

Offline Downix

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Re: Taurus II vs Atlas V for manned launch vehicle
« Reply #22 on: 07/28/2010 10:23 PM »
1) Can NK-33/AJ-26 be built in the US rather than the Ukraine? Even if it is still a foreign design, construction, testing and integration in the US will make a lot of people happier.
Aerojet has the rights to US production, but it's unlikely the economic case would close compared to restarting production in Russia. (As Ed says, it is not and never was Ukrainian. It also hasn't been produced since the Soviets canceled the N1 in the 70s)

If the government were going to pay for US production of a Russian engine, it might be better to bite the bullet and do the RD-180 (for which US production rights also exists.)
Not necessarily.  The NK-33 has some advantages over the RD-180, such as being more versitile in fuel uses, better T/W ratio, and I understand that it is cheaper to produce.
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Online ugordan

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Re: Taurus II vs Atlas V for manned launch vehicle
« Reply #23 on: 07/28/2010 10:27 PM »
2 NK-33s also have a disadvantage: two turbopump sets instead of one. Which wouldn't be bad in itself except vehicle controllability depends on both engines running. All other things equal (not that they likely *are*), that would increase chances of a LOM.

Offline Downix

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Re: Taurus II vs Atlas V for manned launch vehicle
« Reply #24 on: 07/28/2010 10:58 PM »
2 NK-33s also have a disadvantage: two turbopump sets instead of one. Which wouldn't be bad in itself except vehicle controllability depends on both engines running. All other things equal (not that they likely *are*), that would increase chances of a LOM.
But not all turbopumps are created the same.  The NK-33's, IIRC, use a much simpler turbopump system, for less points of failure, than the RD-180.  If someone knows better, of course, feel free to correct me.

I'd trust two NK-33's more than a single RD-180, and I'd still trust my first borns life to the RD-180, so that's saying something.  8)
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Offline zaitcev

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Re: Taurus II vs Atlas V for manned launch vehicle
« Reply #25 on: 07/29/2010 12:17 AM »
They still haven't got an RL-10 -- how primitive!
You are gravely mistaken. KBKhA officially acquired the RL-10 know-how (in the process of collaboration with P&WR) and produced a "Red RL-10" called RD-0146. It sports some improvements and RW&R is marketing it outside of Russia. It is also baselined in the SPKG "Rus-M" (or was until RKKE's Zenit-based alternative was submitted last month). So, although it haven't taken the flight, they've got an RL-10 all right.
-- Pete

Online Salo

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Re: Taurus II vs Atlas V for manned launch vehicle
« Reply #26 on: 07/29/2010 11:46 AM »
Russia produce staged combustion cryogenic engine KVD-1 for GSLV upper stage.

Offline alexw

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Re: Taurus II vs Atlas V for manned launch vehicle
« Reply #27 on: 08/01/2010 05:44 AM »
They still haven't got an RL-10 -- how primitive!
You are gravely mistaken. KBKhA officially acquired the RL-10 know-how (in the process of collaboration with P&WR) and produced a "Red RL-10" called RD-0146. It sports some improvements and RW&R is marketing it outside of Russia. It is also baselined in the SPKG "Rus-M" (or was until RKKE's Zenit-based alternative was submitted last month). So, although it haven't taken the flight, they've got an RL-10 all right.
   
    I apologize since I realize that my sarcasm may have been rather opaque, especially to any nonnative (Russian?) speakers.

    As for RD-0146, it hasn't flown yet. How would KBKhA ``officially'' acquire the RL-10 technology in light of ITAR?

    If I understand correctly, Russia has never placed into operation a hydrolox upper stage, certainly nothing with both the thrust and isp of RL-10B-2. In that sense, Russian rockets seem "primitive", technologically, compared to the conspicuous US investment in liquid hydrogen. Yet e.g. Proton still has very good performance and low cost, and for non-escape-velocity missions, the Russian choices in kerosene seem to have led to better value across most of the rocket spectrum. SpaceX (and Orbital) seem to be validating that proposition.
    -Alex

Offline alexw

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Re: Taurus II vs Atlas V for manned launch vehicle
« Reply #28 on: 08/01/2010 05:45 AM »
Russia produce staged combustion cryogenic engine KVD-1 for GSLV upper stage.
     Is RD-56 really staged combustion?
        -Alex

Online Salo

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Re: Taurus II vs Atlas V for manned launch vehicle
« Reply #29 on: 08/01/2010 08:50 PM »
Yes it is.

Offline alexw

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Re: Taurus II vs Atlas V for manned launch vehicle
« Reply #30 on: 08/01/2010 10:47 PM »
Yes it is.
   Wow. Is this among the smallest staged-combustion engine built? Did they choose not to use the expander cycle deliberately for performance? Its isp is no better than RL-10B-2, but it's a lot better than early RL-10's of comparable thrust. Impressive.
    -Alex

Offline hop

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Re: Taurus II vs Atlas V for manned launch vehicle
« Reply #31 on: 08/01/2010 11:02 PM »
Its isp is no better than RL-10B-2, but it's a lot better than early RL-10's of comparable thrust. Impressive.
    -Alex
Keep in mind it was originally developed in the 60s as an upgrade for the N1 program.  In the intervening years, there were numerous proposals and some development efforts for various LH2 upper stages. Which gets back to your original point... The Soviets developed LH2 technology quite early on, but for whatever reason never flew it (except for Energia)

Offline Patchouli

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Re: Taurus II vs Atlas V for manned launch vehicle
« Reply #32 on: 08/02/2010 01:04 AM »

AJ-10 doesn't develop enough thrust.  It is also a pressure fed engine, which would result in a heavier, less capable upper stage.

For this application, the only reasonable U.S. option would have been RL-10, but that would have added the expense of hydrogen fuel infrastructure. 

 - Ed Kyle

The AJ10-137 used as the SPS on Apollo might have enough thrust at 21,919lbs thrust but it's still a pressure fed engine.
http://www.astronautix.com/engines/aj10.htm
« Last Edit: 08/02/2010 01:09 AM by Patchouli »

Offline Antares

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Re: Taurus II vs Atlas V for manned launch vehicle
« Reply #33 on: 08/02/2010 01:56 PM »
Did they choose not to use the expander cycle deliberately for performance? Its isp is no better than RL-10B-2, but it's a lot better than early RL-10's of comparable thrust.

Those Isp and thrust results are as expected.  There's no physical reason for Isp to be higher on staged combustion vs expander of the same mixture ratio.  Expander is not good for a high thrust application, due to vehicle mass, but staged is.
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Online edkyle99

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Re: Taurus II vs Atlas V for manned launch vehicle
« Reply #34 on: 08/02/2010 02:16 PM »
    If I understand correctly, Russia has never placed into operation a hydrolox upper stage, certainly nothing with both the thrust and isp of RL-10B-2. In that sense, Russian rockets seem "primitive", technologically, compared to the conspicuous US investment in liquid hydrogen. Yet e.g. Proton still has very good performance and low cost, and for non-escape-velocity missions, the Russian choices in kerosene seem to have led to better value across most of the rocket spectrum. SpaceX (and Orbital) seem to be validating that proposition.
    -Alex

Taurus 2E would show what a "modern" Russo-Ukrainian rocket would look like.  Note that it would, with only two stages and three engines, do what Soyuz 2 does with 6-7 propulsion units and 6-7 engines. 

Kinda funny that the "U.S." "Russian" rockets (Atlas 5 and Taurus 2) are more "advanced" than Russia's "Russian" rockets.  That, IMO, is because the old Soviet launch systems work so well it is hard to let them go.

 - Ed Kyle
« Last Edit: 08/02/2010 06:12 PM by edkyle99 »

Offline strangequark

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Re: Taurus II vs Atlas V for manned launch vehicle
« Reply #35 on: 08/02/2010 07:13 PM »

Those Isp and thrust results are as expected.  There's no physical reason for Isp to be higher on staged combustion vs expander of the same mixture ratio.  Expander is not good for a high thrust application, due to vehicle mass, but staged is.

You could derive an Isp benefit for staged upper-stage versus expander, couldn't you?:

Higher chamber pressure -> Smaller throat for same thrust -> Larger expansion ratio for same overall engine size -> Higher Isp within same nozzle length constraint.

They just went with a very conservative chamber pressure on the RD-56.
« Last Edit: 08/02/2010 07:15 PM by strangequark »

Online Salo

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Re: Taurus II vs Atlas V for manned launch vehicle
« Reply #36 on: 08/02/2010 08:58 PM »
Wow. Is this among the smallest staged-combustion engine built?

    -Alex
The smallest staged-combustion flown engine is 11D33 with trust 66.7 KN. But several developed russian engines will have a trust for about 50 KN (11D58MF)  and even 20 KN  (RD-161, S5.88, S5.149). 

Offline Dmitry_V_home

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Re: Taurus II vs Atlas V for manned launch vehicle
« Reply #37 on: 08/08/2010 05:48 PM »
Orbital spaceship ( + 2nd stage with RD-0124) :
« Last Edit: 08/08/2010 05:55 PM by Dmitry_V_home »

Offline Downix

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Re: Taurus II vs Atlas V for manned launch vehicle
« Reply #38 on: 08/08/2010 08:16 PM »
Orbital spaceship ( + 2nd stage with RD-0124) :

Here is Orbitals own proposal for Orion, so a likely starting point:

http://www.astronautix.com/craft/cevbital.htm

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Offline antonioe

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Re: Taurus II vs Atlas V for manned launch vehicle
« Reply #39 on: 08/14/2010 05:47 PM »
There's no physical reason for Isp to be higher on staged combustion vs expander of the same mixture ratio.  Expander is not good for a high thrust application, due to vehicle mass, but staged is.

Well.... there is no FIRST-ORDER effect of the cycle type on Isp, but there are some small, second-order effects that can add up to 1-2% improvements in Isp.  Expander cycle designs have to cope with the additional design constraint of both starting and maintaining steady-state thermal balance between the enthalpy going INTO the fluid due to expansion and the enthalpy going OUT OF the fluid due to the work in the turbine.

A consequence of this balance is a constrained fluid inlet temperature than then translates into a combustion chamber temperature which in turn affects C* (the total energy produced by combustion of a unit mass of fuel+oxidizer mixture) and (I'm speculating here, those of you that know better please correct me) a higher Carnot efficiency due to the higher "high" cycle temperature (the effective "low" temperature depending on how well-matched the expansion through the nozzle is with the ambient pressure).

A reminder... 2% of 330 seconds is 6.5 seconds!!!
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