**[Request For Information (RFI) - NASA Advanced Propulsion System
Development]{.underline}**

**[on Composite Overwrapped Pressure Vessels (COPVs) for Cryogenic
Propellants]{.underline}**

**Purpose**

The purpose of this Request for Information (RFI) is to obtain a
response from vendors for Composite Overwrapped Pressure Vessels (COPV)
regarding the costs and delivery times required to design, analyze, and
build COPVs per the requested specifications. Information is requested
for vessels that will represent flight materials and processes.
Information is being requested for capabilities of COPV vendors
regarding performance of large vessels storing fluids at cryogenic
conditions and if there is previous experience and/or research and
development efforts that have been conducted for the use of such vessels
for space flight systems and flight certified carbon fibers such as
Toray T-1000. It is preferred that information be given for vessels used
to establish an A-basis allowable per ANSI/AIAA S-081A-2006. NASA's
immediate need for this capability is to perform development tests on
propulsion system designs that use cryogenic propellants. Current
options for fuel and oxidizer combinations include liquid methane (LCH4)
and liquid oxygen (LOX). Consequently, the goal of this RFI is to survey
industry interest in accommodating the delivery and testing of small
scale carbon wrapped COPVs at relatively low costs for propulsion
systems with cryogenic propellants to buy down the risk for full scale
vessel design and development. A schematic of the LOX/LCH4 propulsion
system is shown in Figure 1, which is a pressurized system using gaseous
Helium (GHe) to move the fuel and oxidizer to the engine inlet valves.
The application for which this is being evaluated would be a Service
Module or a lunar lander vehicle. This is in support of NASA's
Exploration Technology Development Program (ETDP) in addressing
technology needs for these vehicles.

![](media/image1.wmf){width="6.745833333333334in"
height="4.5055555555555555in"}

**Figure 1: Cryogenic Oxygen and Methane Propulsion System Schematic**

It must be noted that the responses for this RFI will be used in the
future to generate a detailed Statement of Work for the procurement of
test articles.

**Requested Specifications**

[Shape:]{.underline}

Sphere, Cylinder, Oblate Spheroid or other shape that has been
fabricated and wrapped for previous programs to accommodate the storage
of large volumes of liquid for space applications.

[Fill Ports:]{.underline}

2 boss ports with AS5202 thread form

[Structural Supports:]{.underline}

Carbon fiber skirt on girth for spheres, carbon fiber skirt on dome to
barrel on cylinder. Supports shall be sized to support the entire weight
load of the vessel and stored fluid media. The weight load is based on
the volume of the vessel and the properties of the stored fluids which
are: LOX and LCH4.

[MOP:]{.underline}

The Maximum Operating Pressure for the vessels is 375 psia.

[Liner:]{.underline}

The liner material shall be compatible with LOX and LCH4. A quantity of
2 liners shall be subjected to thermal cycles with each fluid to
determine expansion and contraction versus temperature. Burst tests with
LN2 shall be performed to determine the load carrying capacity and the
strain levels versus pressure.

[Liner Thickness:]{.underline}

Weight savings is a primary design parameter for space flight propulsion
systems. Information is requested on how thin the liner can be
fabricated and still accommodate welding and wrapping procedures.

[Fiber:]{.underline}

The requested fiber is Toray T-1000. A response can be provided with
other fibers that have similar properties to T-1000. The main objective
is to get cost and delivery for vessels based on the availability of
Toray T-1000.

[Volume Fiber Ratio:]{.underline}

0.65 +/- 0.05

[Minimum Burst Pressure:]{.underline}

The minimum burst pressure for the COPV shall be 563 psia, which is 1.5
X MOP.

[Proof Pressure:]{.underline}

The proof pressure is 469 psia, which is 1.25 X MOP.

[Minimum Inside Diameter:]{.underline}

The minimum inside diameter shall be 36.0 in.

[Minimum Volume:]{.underline}

The minimum volume shall be 24,430 cu. in., which is the volume of a
sphere with a 36" Inside Diameter. Information is also requested on the
capabilities and cost to fabricate COPVs with diameters that could
provide volumes as large as 100,000 cu. in.

[Helical/Hoop Design Stress Ratio:]{.underline}

75% (typical for flight design of cylinders)

[Liner/Overwrap Interface:]{.underline}

The liner to overwrap interface shall be a non-bonded interface such
that the liner will expand and contract independently of the overwrap at
cryogenic temperatures to prevent buckling of the liner based on the
difference of coefficient of thermal expansion of the liner versus the
overwrap.

[Thermal Cycles:]{.underline}

Each vessel shall be subjected to 5 thermal cycles with LN2 at 14.7
psia. Inspections of the liner shall be performed after each thermal
cycle to verify the non-bonded interface.

[Pressure Cycles:]{.underline}

Each vessel shall be subjected to 100 pressure cycles from 14.7 to 375
psia with LN2.

[Burst Tests:]{.underline}

Burst tests shall be performed on 2 vessels to determine the
variability. The target minimum pressure increase rate for the burst
tests is 50psi/sec. The target range for burst factors is 1.6 to 1.9.

[Deliverables:]{.underline}

A total of 2 liners shall be fabricated, thermal cycled and burst. A
total of 2 COPVs shall be fabricated, thermal cycled, pressure cycled
and burst and a total of 1 COPV shall be thermal cycled and delivered to
NASA Johnson Space Center.

**RFI Response Content Instructions**

At a minimum, the RFI response should include the following:

1.  A statement indicating your company's interest in the fabrication
    and delivery of Composite Overwrapped Pressure Vessels for cryogenic
    propellant storage.

2.  A list of tasks that your company believes it will need to perform
    to accommodate the delivery of the proposed COPVs per the requested
    specifications. The primary tasks need to include but not be limited
    to: design, analysis, fabrication and testing.

3.  A cost and delivery estimate for performing the full list of tasks
    and a payment milestone profile.

4.  A summary of relevant experiences and history of your company
    related to the development of hardware for space applications at
    cryogenic conditions.

5.  The capabilities of your test facilities related to performing and
    collecting data for the specified tests using cryogenic fluids.

6.  The size of you company.

7.  All other information that your company considers to be pertinent to
    this activity.