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Taurus II vs Atlas V for manned launch vehicle
by
dbooker
on 23 Jul, 2010 18:49
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I keep hearing that people are pushing for using Taurus II as a potential launch vehicle for commercial crew. Can someone explain how using a Russian built first stage for Taurus II is acceptable while it is not acceptable to use an Atlas V because it has a Russian built engine for it's first stage? Or is this just Congressional logic, meaning it depends on who gives the biggest contributions.
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#1
by
kevin-rf
on 23 Jul, 2010 23:00
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I thought it was Ukrainian built tanks and pre-Soviet collapse built engines... In other words, no "Russian" parts. Though when aerojet runs out of AJ-26's it is a different story comrade
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#2
by
Antares
on 24 Jul, 2010 00:05
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No one is pushing for Taurus II. It was Frank Culbertson playing to the crowd at a lunch lecture to a Florida space club near the Cape. I don't see this class of vehicle being able to lift an adequately sized capsule.
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#3
by
Downix
on 24 Jul, 2010 00:37
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No one is pushing for Taurus II. It was Frank Culbertson playing to the crowd at a lunch lecture to a Florida space club near the Cape. I don't see this class of vehicle being able to lift an adequately sized capsule.
The Taurus II first stage is as capable as the Atlas V first stage, it's the upper stage which is the lynch pin. Substitute a suitable upper stage, it would be more than suitable.
And they have already stated that the AJ26 supply is not a concern, that they can start up production if the need arises.
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#4
by
ugordan
on 24 Jul, 2010 01:59
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The Taurus II first stage is as capable as the Atlas V first stage
T-II has roughly 3/4 of Atlas V liftoff thrust and Atlas is pretty much maxed out in terms of T/W so it is not as capable. That 3/4 in fact very roughly translates to their stated max LEO performance ratio.
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#5
by
zaitcev
on 24 Jul, 2010 22:44
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I keep hearing that people are pushing for using Taurus II as a potential launch vehicle for commercial crew. Can someone explain how using a Russian built first stage for Taurus II is acceptable while it is not acceptable to use an Atlas V because it has a Russian built engine for it's first stage? Or is this just Congressional logic, meaning it depends on who gives the biggest contributions.
Your question is predicated on badly confused geography and geopolitics. Taurus II first stage is designed and built in Ukraine, which is not Russia. Ukraine does not have any designs for geopolitical parity with U.S. Ukraine and Lybia are the only two countries that voluntarily gave up nuclear weapons. Meanwhile Russia just put a new ICBM RS-24 on combat alert.
-- Pete
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#6
by
Downix
on 26 Jul, 2010 04:48
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The Taurus II first stage is as capable as the Atlas V first stage
T-II has roughly 3/4 of Atlas V liftoff thrust and Atlas is pretty much maxed out in terms of T/W so it is not as capable. That 3/4 in fact very roughly translates to their stated max LEO performance ratio.
No. Check again:
Atlas V has 3.850 MN on takeoff
Taurus II has 3.265 MN on takeoff.
This means the Taurus II has 85% of the thrust of the Atlas V. Now, let us look at the weight:
Atlas V first stage: 306,914 kg
Taurus II first stage: 261,187 kg
And as you can see, the first stage is also only 85% of the weight. So my original argument, a better upper stage could bring it to within the same range, fine for crewed operation.
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#7
by
aquanaut99
on 26 Jul, 2010 05:25
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Ukraine and Lybia are the only two countries that voluntarily gave up nuclear weapons.
There's also South Africa, Kazakstan and Belarus. And Lybia never actually had nukes, only a development program they decided not to pursue any further. Several other countries have done the same in the past; Brazil, Argentina, Sweden and Switzerland come to mind...
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#8
by
edkyle99
on 26 Jul, 2010 14:03
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The Taurus II first stage is as capable as the Atlas V first stage
T-II has roughly 3/4 of Atlas V liftoff thrust and Atlas is pretty much maxed out in terms of T/W so it is not as capable. That 3/4 in fact very roughly translates to their stated max LEO performance ratio.
No. Check again:
Atlas V has 3.850 MN on takeoff
Taurus II has 3.265 MN on takeoff.
This means the Taurus II has 85% of the thrust of the Atlas V. Now, let us look at the weight:
Atlas V first stage: 306,914 kg
Taurus II first stage: 261,187 kg
And as you can see, the first stage is also only 85% of the weight. So my original argument, a better upper stage could bring it to within the same range, fine for crewed operation.
I would be interested to know where you got the Taurus 2 first stage mass and thrust. Both numbers seem high. Other published data gives 3.0199 MN sea level thrust. A 261 tonne first stage would be too heavy to lift with that thrust.
Orbital's user guide says that the first stage burn will last for 235 seconds, but also says that max G-loading will be 6.0. That implies throttling, which means that propellant load can't be estimated by full mass rate times 235 seconds. I'm guessing that the first stage weighs something like 235 tonnes loaded.
- Ed Kyle
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#9
by
Salo
on 26 Jul, 2010 14:35
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NK-33 had sea-level trust 1.6316 MN during first test firing on March, 6th, 2010 in Samara.
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#10
by
Downix
on 26 Jul, 2010 16:08
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The Taurus II first stage is as capable as the Atlas V first stage
T-II has roughly 3/4 of Atlas V liftoff thrust and Atlas is pretty much maxed out in terms of T/W so it is not as capable. That 3/4 in fact very roughly translates to their stated max LEO performance ratio.
No. Check again:
Atlas V has 3.850 MN on takeoff
Taurus II has 3.265 MN on takeoff.
This means the Taurus II has 85% of the thrust of the Atlas V. Now, let us look at the weight:
Atlas V first stage: 306,914 kg
Taurus II first stage: 261,187 kg
And as you can see, the first stage is also only 85% of the weight. So my original argument, a better upper stage could bring it to within the same range, fine for crewed operation.
I would be interested to know where you got the Taurus 2 first stage mass and thrust. Both numbers seem high. Other published data gives 3.0199 MN sea level thrust. A 261 tonne first stage would be too heavy to lift with that thrust.
Orbital's user guide says that the first stage burn will last for 235 seconds, but also says that max G-loading will be 6.0. That implies throttling, which means that propellant load can't be estimated by full mass rate times 235 seconds. I'm guessing that the first stage weighs something like 235 tonnes loaded.
- Ed Kyle
The COTS documentation on NASAs website has the Taurus II weight, I even found it broken down per-stage and even per-load. 65000 kg of LOX, for instance.
The thrust is also in Orbitals documentation. Aerojet found that the NK-33 was never pushed to its limits, and could actually support more thrust. The AJ26 can now throttle to 108%.
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#11
by
Antares
on 27 Jul, 2010 00:22
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Dang it! I was about to argue, but a bigger tragedy has befallen us. lpre.de seems to be gone. Time for the Wayback Machine....which links to
http://www.novosti-kosmonavtiki.ru/content/numbers/240/25.shtml which shows a graph that the engine was tested by the Russians at ~126%. And, inductively, no, this work could not have been done by Aerojet and then published by the Russians because eye-tar would preclude it.
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#12
by
edkyle99
on 27 Jul, 2010 00:38
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The COTS documentation on NASAs website has the Taurus II weight, I even found it broken down per-stage and even per-load. 65000 kg of LOX, for instance.
The thrust is also in Orbitals documentation. Aerojet found that the NK-33 was never pushed to its limits, and could actually support more thrust. The AJ26 can now throttle to 108%.
Super. Thanks!
Use of RD-0124 as the second stage engine seems to point toward some first stage propellant offloading, unless the NK-33 thrust is increased even more than 108%. 114% (tested in the 1990s) would get Taurus 2e back up to full first stage propellant loading, and easily to the claimed 8.7 tonnes to LEO (perhaps 9 tonnes) from Cape Canaveral.
- Ed Kyle
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#13
by
Downix
on 27 Jul, 2010 17:35
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The COTS documentation on NASAs website has the Taurus II weight, I even found it broken down per-stage and even per-load. 65000 kg of LOX, for instance.
The thrust is also in Orbitals documentation. Aerojet found that the NK-33 was never pushed to its limits, and could actually support more thrust. The AJ26 can now throttle to 108%.
Super. Thanks!
Use of RD-0124 as the second stage engine seems to point toward some first stage propellant offloading, unless the NK-33 thrust is increased even more than 108%. 114% (tested in the 1990s) would get Taurus 2e back up to full first stage propellant loading, and easily to the claimed 8.7 tonnes to LEO (perhaps 9 tonnes) from Cape Canaveral.
- Ed Kyle
You are reading my mind. Pity Orbital or Aerojet are not hiring anything I'm qualified for...
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#14
by
edkyle99
on 27 Jul, 2010 18:17
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Use of RD-0124 as the second stage engine seems to point toward some first stage propellant offloading, unless the NK-33 thrust is increased even more than 108%. 114% (tested in the 1990s) would get Taurus 2e back up to full first stage propellant loading, and easily to the claimed 8.7 tonnes to LEO (perhaps 9 tonnes) from Cape Canaveral.
- Ed Kyle
You are reading my mind. Pity Orbital or Aerojet are not hiring anything I'm qualified for...
Notice that Taurus 2 does what Soyuz 2 can do, but with only two stages and three engines rather than six propulsion modules/engines. But here's the kicker. Being able to restart that second stage RD-0124 would allow the rocket to duplicate Soyuz 2-1b/Fregat capabilities - also with only two stages. (Of course a restartable RD-0124 could provide the same stage-reducing benefit for Soyuz).
- Ed Kyle
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#15
by
bad_astra
on 28 Jul, 2010 14:29
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Why buy Russian vehicles to put passengers on. We can just buy seats on Soyuz, at that point.
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#16
by
Downix
on 28 Jul, 2010 15:39
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Why buy Russian vehicles to put passengers on. We can just buy seats on Soyuz, at that point.
Only 5 Soyuz per year, don't forget. More options is always good.
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#17
by
Ben the Space Brit
on 28 Jul, 2010 21:17
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Two questions that you know that the politicians will ask:
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.
2) Is there a US upper stage alternative?
IMHO at least, for (2), I think that the AJ-10 is an obvious answer.
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#18
by
edkyle99
on 28 Jul, 2010 21:25
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Two questions that you know that the politicians will ask:
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.
NK-33 is a Russian, not Ukrainian, engine. The first stage itself is Ukrainian, based on Zenit 2/3 tooling, tankage, and structures. I doubt very much that we will ever see this engine manufactured in the U.S..
2) Is there a US upper stage alternative?
IMHO at least, for (2), I think that the AJ-10 is an obvious answer.
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
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#19
by
alexw
on 28 Jul, 2010 21:48
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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.
It all seems a bit ironic. The US led the way with "Taming liquid hydrogen" -- RL-10, J-2, Centaur all seemed so much more advanced than the Russian multiple-upper-stage kerolox and hypergolic approach, not to mention the deranged magnificence of SSME. Europe was a little better with HM7, but still gas-generator. Russia leaped to catch up with RD-0120, then lost it. They
still haven't got an RL-10 -- how
primitive! 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. The price of both is that you lose domestic vertical integration.
What does the internal worldview from Pratt and Aerojet look like?
-Alex
