Commercial and US Government Launch Vehicles > ULA - Delta, Atlas, Vulcan

ULA Innovation: Integrated Vehicle Fluids (IVF)

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Robotbeat:
Much better to just stretch the upper stage and use it as a tanker.

Kabloona:

--- Quote from: sdsds on 04/10/2015 05:12 am ---
--- Quote from: Designvis on 04/07/2015 03:39 pm ---IVF works beautifully in concert with fuel cells and solar electric systems.  You let those systems handle long-duration low-level power demands and turn IVF on when you need to do heavy lifting. This enables them to be compact and light since they don't have to handle peak loads.  You can even eliminate dedicated controllers and power processing units which are major elements in the cost of those systems. The mission transition time is dependent on tank thermo, power level and other stuff but its usually after many days. 

--- End quote ---

I didn't understand this bit about "mission transition time." What exactly happens "after many days?"

Thanks!

--- End quote ---

Sounds like maybe transition to solar power only, after the cryos have boiled off.

jongoff:

--- Quote from: Kabloona on 04/11/2015 02:07 pm ---
--- Quote from: sdsds on 04/10/2015 05:12 am ---
--- Quote from: Designvis on 04/07/2015 03:39 pm ---IVF works beautifully in concert with fuel cells and solar electric systems.  You let those systems handle long-duration low-level power demands and turn IVF on when you need to do heavy lifting. This enables them to be compact and light since they don't have to handle peak loads.  You can even eliminate dedicated controllers and power processing units which are major elements in the cost of those systems. The mission transition time is dependent on tank thermo, power level and other stuff but its usually after many days. 

--- End quote ---

I didn't understand this bit about "mission transition time." What exactly happens "after many days?"

Thanks!

--- End quote ---

Sounds like maybe transition to solar power only, after the cryos have boiled off.

--- End quote ---

My guess is that he's saying that solar arrays only start being a net win after "many days", and that before that threshold it's lighter and cheaper to just use the boiled off propellant. This might change for missions in deep space where the natural boiloff rate is a lot lower.

~Jon

sdsds:

--- Quote from: jongoff on 04/11/2015 05:59 pm ---
--- Quote from: Kabloona on 04/11/2015 02:07 pm ---
--- Quote from: sdsds on 04/10/2015 05:12 am ---What exactly happens "after many days?"

--- End quote ---

Sounds like maybe transition to solar power only, after the cryos have boiled off.

--- End quote ---

My guess is that he's saying that solar arrays only start being a net win after "many days"

--- End quote ---

Thanks, these both seem like reasonable interpretations. (I favor the second principally because I don't understand how a stage with absolutely no propellant helps a mission at all, even if it has electric power.)


--- Quote from: jongoff on 04/11/2015 05:59 pm ---This might change for missions in deep space where the natural boiloff rate is a lot lower.

--- End quote ---

Indeed! I'm wondering if they envision being able to retain propellant long enough that the IVF thrusters could provide propulsion for missions with trajectories like that of LADEE? How about GRAIL?

TrevorMonty:
ULA long term plans are for a ACES upper stage with better insulation and fuel life measured in weeks and maybe months in some versions. A IVF Centuar is a means of testing the technology and reducing costs, improving stages life from hours to weeks is just a bonus.

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