ATK announce Liberty KSC test flights, reveal crew spacecraft with MLAS

[alexw]

I'm wondering how Liberty can compete, since it carries twice as much payload or more to the ISS orbit as its CCDev competitors.  That means, if fiscal realism is followed, that it should cost twice as much.
NASA does award these things to the lowest bidder, right?

~ twice the payload.
It can be competitive if 1 launch of a Liberty costs less than 2 launches of its rivals.

    Perhaps for propellant, but not so much for crew. 
            -Alex

[edkyle99]

Liberty may launch the same number of crew but they could for instance take more luggage with them.  Several tons of food, water and air in the trunk may remove the need for a separate cargo launch.

All fine and good, if a means can be provided to carry the cargo, but isn't CCDev, the contract that Liberty is aiming for, just a crew carrying mission?

 - Ed Kyle

[Lurker Steve]

Liberty may launch the same number of crew but they could for instance take more luggage with them.  Several tons of food, water and air in the trunk may remove the need for a separate cargo launch.

All fine and good, if a means can be provided to carry the cargo, but isn't CCDev, the contract that Liberty is aiming for, just a crew carrying mission?

 - Ed Kyle

If Orbital was able to mount the Cygnus propulsion module onto a full-sized MPLM, does this have the capacity to lift it to the proper orbit ?

Also, those solids in the MLAS must be pretty heavy, right ? I assume this capsule would not be able to make it off the ground on a Atlas 402 or Falcon 9, so the crew vehicle is specific to Liberty.

[A_M_Swallow]

Liberty may launch the same number of crew but they could for instance take more luggage with them.  Several tons of food, water and air in the trunk may remove the need for a separate cargo launch.

All fine and good, if a means can be provided to carry the cargo, but isn't CCDev, the contract that Liberty is aiming for, just a crew carrying mission?

 - Ed Kyle

CCDev is a development "contract", production contracts will have to be agreed.  The COTS equivalent was the Commercial Resupply Services (CRS) contracts.  SpaceX was promised 12 launches.  At 3 launches a year in ~2013 + 12/3 = ~2017 new cargo bids may be accepted.

[Kaputnik]

Can someone remind me why the Liberty upper stage is upside-down compared to the Ares I stage? I skimmed the present thread. Hope I didn't miss it.

Literally speaking the stage is not upside-down. The tankage is reversed however, when comparing the Ares-1 US to the Liberty US.
The Liberty US has the LOX tank sitting on top of the LH2 tank, separated by a common bulkhead. On the Ares-1 US the order was reversed: the LH2 tank sat on top of the LOX tank, also separated by a common bulkhead.

As to why NASA chose the Ares-1 US configuration: dunno for sure. Might have something to do with center of gravity. But my guess is that someone else on this forum might be able to answer that question for ya.

The tank with the higher density fluid should be as near to the CoG, to keep the moment of inertia as low as possible, to reduce the effort needed for piloting (balancing) of the LV. High MoI increases max thrust vector actuation angles, thus more komplex TVA kinematics, more deltaV losses due to TVA, more secondary energy storage needed for  TVA (hydraulic => more high pressure hydraulic oil storage; electric => more high current batteries), less stability of piloting loop, etc. At some point the piloting of the LV get's unfeasible.
During Ares I the fear that piloting of the stick would be impossible was a major reason for the Ares-1X-test, so I can't really believe that they are ok with the even larger MoI for Liberty with LOx-tank @ front of upper stage... Surprising...

It sounds like you know more about this than I do, but if I am understanding you correctly what you are seeing seems to go against my intuition.
I would have thought that the TVC-enabled motor should be located as far from the CG as possible. This would mean that smaller TVC movements would be required to effect a change, therefore meaning greater overall efficiency. No?

[FinalFrontier]

Great article and tons of information in it and this thread as usual, excellent work by Chris on this one. I personally had not been following anything about liberty since its original announcement (as I have not had time or interest) so it was good to get a complete picture.


Rather interested to see how using the Vulcain based upper stage works out, somehow I think that's going to be easier said then done. Also going to be interested to see if they can really start test flights as early as two years from now, that seems quite optimistic.

As far as being cost effective....well, I just don't see that ever happening with this vehicle, but who knows.


One other thing: Jim, the stick is back. 

[benjaminhigginbotham]

Well done to SVC for webcasting it.

Thanks. Thought this an important one to get. Trying my best to get as many events like this as I can.

[spacejulien]

It sounds like you know more about this than I do, but if I am understanding you correctly what you are seeing seems to go against my intuition.
I would have thought that the TVC-enabled motor should be located as far from the CG as possible. This would mean that smaller TVC movements would be required to effect a change, therefore meaning greater overall efficiency. No?

Of course below a certain distance between gimbal and CoG you would end up non-steerable, too. But that is not really the design driver.
Have a look at Atlas, Delta or any other cryogenic upper stage, all have the LOx tank at the stage rear, allthough it isn't optimal for upper stage piloting.
But in first stage flight esp. when going through MaxQ and zones of high altitude winds the CoG of the complete vehicle usually anyhow is far enough away to be steerable.
So, when designing the launch vehicle you trade whether to have the that distance a bit increased by putting the upper stage LOx tank in front of the upper stage LH2 tank or to put the two LOx tanks of first and upper stage as close together as possible to reduce the moment of inertia of the vehicle. Imagine the wind imparting an involuntary rotation on the vehicle. By gimballing the engine that has to be stopped and a counter-rotation is required to right up the vehicle again and then that has to be stopped, too. That's an awful lot of gimballing and the moment of inertia rises with the square of the distance of the main masses from their common CoG. So the reduction of MoI usually wins in such overall trade. For proof see the designs of the upper stages mentioned and their heritage incl. Saturn S-II and S-IVB.

[Patchouli]

The Vulcain 2 had most of the air-start issues addressed awhile ago, actually.  it is not a major effort to deliver.

The SSME required head pressure to start up but from what I can tell from test videos Vulcain seems to use a start cartridge.
Note the black smoke from the turbo pump exhaust.
<a href="http://www.youtube.com/v/gHN4xeR_C30&rel=1" target="_blank">http://www.youtube.com/v/gHN4xeR_C30&rel=1</a>

The this means the engine probably could not restart unless modified so any payloads would have to make the second orbital insertion burn themselves which also answers why the vehicle has a service module.

[edkyle99]

Of course below a certain distance between gimbal and CoG you would end up non-steerable, too. But that is not really the design driver.
Have a look at Atlas, Delta or any other cryogenic upper stage, all have the LOx tank at the stage rear, allthough it isn't optimal for upper stage piloting.
But in first stage flight esp. when going through MaxQ and zones of high altitude winds the CoG of the complete vehicle usually anyhow is far enough away to be steerable.
So, when designing the launch vehicle you trade whether to have the that distance a bit increased by putting the upper stage LOx tank in front of the upper stage LH2 tank or to put the two LOx tanks of first and upper stage as close together as possible to reduce the moment of inertia of the vehicle. Imagine the wind imparting an involuntary rotation on the vehicle. By gimballing the engine that has to be stopped and a counter-rotation is required to right up the vehicle again and then that has to be stopped, too. That's an awful lot of gimballing and the moment of inertia rises with the square of the distance of the main masses from their common CoG. So the reduction of MoI usually wins in such overall trade. For proof see the designs of the upper stages mentioned and their heritage incl. Saturn S-II and S-IVB.

The EPC is topped by the VEB, which has a clusters of 400N roll - pitch thrusters.  Perhaps their location, on top of the stage, aids in control of this particular configuration, compared with Centaur, for example, which has thrusters near the rear.
http://cs.astrium.eads.net/sp/spacecraft-propulsion/showcase/ariane5-attitude-control-system.html

My guess is that VEB would  fly on Liberty too.

 - Ed Kyle

[Kaputnik]

It sounds like you know more about this than I do, but if I am understanding you correctly what you are seeing seems to go against my intuition.
I would have thought that the TVC-enabled motor should be located as far from the CG as possible. This would mean that smaller TVC movements would be required to effect a change, therefore meaning greater overall efficiency. No?

Of course below a certain distance between gimbal and CoG you would end up non-steerable, too. But that is not really the design driver.
Have a look at Atlas, Delta or any other cryogenic upper stage, all have the LOx tank at the stage rear, allthough it isn't optimal for upper stage piloting.
But in first stage flight esp. when going through MaxQ and zones of high altitude winds the CoG of the complete vehicle usually anyhow is far enough away to be steerable.
So, when designing the launch vehicle you trade whether to have the that distance a bit increased by putting the upper stage LOx tank in front of the upper stage LH2 tank or to put the two LOx tanks of first and upper stage as close together as possible to reduce the moment of inertia of the vehicle. Imagine the wind imparting an involuntary rotation on the vehicle. By gimballing the engine that has to be stopped and a counter-rotation is required to right up the vehicle again and then that has to be stopped, too. That's an awful lot of gimballing and the moment of inertia rises with the square of the distance of the main masses from their common CoG. So the reduction of MoI usually wins in such overall trade. For proof see the designs of the upper stages mentioned and their heritage incl. Saturn S-II and S-IVB.

I've got it now- thanks!
It's a bit like why in boat design you try to avoid putting too much mass at either end- better to concentrate it all in the middle. Same for rockets it would seem.

[Downix]

It sounds like you know more about this than I do, but if I am understanding you correctly what you are seeing seems to go against my intuition.
I would have thought that the TVC-enabled motor should be located as far from the CG as possible. This would mean that smaller TVC movements would be required to effect a change, therefore meaning greater overall efficiency. No?

Of course below a certain distance between gimbal and CoG you would end up non-steerable, too. But that is not really the design driver.
Have a look at Atlas, Delta or any other cryogenic upper stage, all have the LOx tank at the stage rear, allthough it isn't optimal for upper stage piloting.
But in first stage flight esp. when going through MaxQ and zones of high altitude winds the CoG of the complete vehicle usually anyhow is far enough away to be steerable.
So, when designing the launch vehicle you trade whether to have the that distance a bit increased by putting the upper stage LOx tank in front of the upper stage LH2 tank or to put the two LOx tanks of first and upper stage as close together as possible to reduce the moment of inertia of the vehicle. Imagine the wind imparting an involuntary rotation on the vehicle. By gimballing the engine that has to be stopped and a counter-rotation is required to right up the vehicle again and then that has to be stopped, too. That's an awful lot of gimballing and the moment of inertia rises with the square of the distance of the main masses from their common CoG. So the reduction of MoI usually wins in such overall trade. For proof see the designs of the upper stages mentioned and their heritage incl. Saturn S-II and S-IVB.

I've got it now- thanks!
It's a bit like why in boat design you try to avoid putting too much mass at either end- better to concentrate it all in the middle. Same for rockets it would seem.

Right, *except* you'll always have a heavy weight in front, either the upper stage *or* the payload.  This is one of the reasons why AJAX was getting better performance, it was a parallel stage, not serial, allowing for better center of pressure.

[spacejulien]

The EPC is topped by the VEB, which has a clusters of 400N roll - pitch thrusters.  Perhaps their location, on top of the stage, aids in control of this particular configuration, compared with Centaur, for example, which has thrusters near the rear.
http://cs.astrium.eads.net/sp/spacecraft-propulsion/showcase/ariane5-attitude-control-system.html

My guess is that VEB would  fly on Liberty too.

 - Ed Kyle

No, this has nothing to do with pilotability, just imagine Ariane 5 is 750+ mT of liftoff weight, the engine produces 135 mT of vacuum thrust, that's 1350000 N, little attitude control thrusters of 400 N is 0.03% of that... Waaaaaaay to weak to give a contribution.

And it isn't designed like that, pilotability by gimballing the Vulcain is fine.

EPC has LOx @ top of stage, ESC upper stage has LOx @ rear of stage, this is "industry standard", compare Atlas, Delta, Falcon, japanese H2A & -B, Soyuz, etc...

But with the EPC as second stage only Liberty would differ from this "industry standard".

[yg1968]

I was re-reading the CCDev-2 selection statement: ATK (Green for Technical and Green for Business) came in third behind SpaceX (Green and Blue) and Boeing (Blue and Green). They came ahead of Blue Origin (White and Green), ULA (White and White) and SNC (White and Green). They weren't selected because NASA decided to select spacecrafts over LVs. Although the evaluation could be different for CCiCap, it does indicate that ATK could be one of the front runners once more.
http://procurement.ksc.nasa.gov/documents/SelectionStatement-Final_Signed.pdf

[yg1968]

One thing that I am wondering about is how ATK and LM will manage to deal with (or circumvent) subsection 403(6) of the 2010 NASA Authorization bill which states the following (bold are mine):

15 (6) COMMERCIAL CREW RESCUE CAPABILI
16 TIES.—The provision of a commercial capability to
17 provide ISS crew services shall include crew rescue
18 requirements, and shall be undertaken through the
19 procurement process initiated in conformance with
20 this section. In the event such development is initi
21 ated, the Administrator shall make available any rel
22 evant government-owned intellectual property deriv
23 ing from the development of a multi-purpose crew
24 vehicle authorized by this Act to commercial entities
25 involved with such crew rescue capability develop

1 ment which shall be relevant to the design of a crew
2 rescue capability. In addition, the Administrator
3 shall seek to ensure that contracts for development
4 of the multi-purpose crew vehicle contain provisions
5 for the licensing of relevant intellectual property to
6 participating commercial providers of any crew res
7 cue capability development undertaken pursuant to
8 this section. If one or more contractors involved with
9 development of the multi-purpose crew vehicle seek
10 to compete in development of a commercial crew
11 service with crew rescue capability, separate legisla
12 tive authority must be enacted to enable the Admin
13 istrator to provide funding for any modifications of
14 the multi-purpose crew vehicle necessary to fulfill
15 the ISS crew rescue function.