Specs.pdf

PART 1: GENERAL

1.01 DESCRIPTION

Development of higher power electric propulsion (EP) thrusters is driving facility requirements to maintain relevant space-like test environments.

Glenn Research Center (GRC) is the Agency EP competency lead responsible to define and advocate for world-class test capability and Vacuum Facility No. 5 (VF-5) is most utilized large EP chamber at GRC.

There are several requirements to support high-fidelity EP testing. These can vary in magnitude depending upon: EP thruster technology selection and its inherent sensitivity to test environments; selection of specific impulse (at equivalent power levels); and selection of input power levels.

A ‘general’ and over-arching requirement is the need for high pumping speed to maintain high vacuum while running EP thrusters in the facility. This is accomplished with pumping cryopanels that use gaseous helium to cryopump the exhaust gases (typically xenon). The view factor from the helium panels are obscured by liquid nitrogen cooled panels that provide both thermal shielding and act to remove thermal energy from the incoming gases.

The cryopanels in VF-5 were built in the 1980s. Some of them have experienced thermal fatigue failures. In order to increase the reliability of VF-5, we intend to replace the most problematic cryopanels with new, more robust panels that will function similarly but are less susceptible to leak when chilled or warmed quickly.

The end result will be an increased reliability for electric propulsion testing within the simulated space environment of the VF-5 chamber located at the Electric Propulsion Laboratory (EPL) – GRC Building 301.

1.02 SCOPE

NASA is purchasing two cryopanels to replace the NTG panels installed in VF-5.

1.03 GOVERNMENT FURNISHED INFORMATION (GFI)

1. Drawing of the current NTG cryopanels

2. Cryopanel P&ID

3. Piping sketch

4. VF-5 panel support structure assembly

5. Instrumentation list

6. Instrumentation interface sketch

7. Mechanical interface list

8. Mechanical interface sketch

9. Design Parameters

a. Maximum Allowable Working Pressure (MAWP)

b. Design Temperatures

1.04 TRAVEL AND INSPECTION

NASA reserves the right to inspect the fabrication and testing of the cryopanels and associated equipment at the vendor location.

PART 2: QUOTATION

2.01 COST AND SCHEDULE

The contractor shall provide a cost and schedule estimate in response to this solicitation for the products described in Part 3.

PART 3: PRODUCTS

3.01 DRAWINGS

Drawings shall be provided that indicate the external dimensions of the cryopanels and all mechanical and electrical interfaces.

3.02 DESIGN REPORT

A design report shall be provided that, at a minimum, contains the following items.

• Special studies

• Back-up data

• Design Calculations o Thermal analysis o Pumping speed o MAWP at design temperature o Weight o Structural

• Manuals

• Catalog cuts

• Results of pressure leak test

• Results of helium leak test

• Material list, mill test reports, and material certifications/specifications

• Welder's Qualification Documentation (WPS, PQR, and WPQ)

• Non-Destructive Examination Reports (Visual, Radiography)

3.03 CRYOPANELS

The contractor shall provide two (2) cryopanel assemblies

Cryopanel Design Requirements

Design cryopanels for installation within the existing vacuum chamber. Cryopanels as defined by this project are cryogenic pumping surface(s) which are configured by shape, quantity, and use to meet the technical requirements. Salient features of this element are as follows.

i. The combined leak rate for both cryopanels shall be less than 5×10-8 standard cc/s, air.

Rationale: Standard achievable leak rates for vacuum equipment and hardware.

ii. Cryopanel pumping speed estimate, consistent with American Vacuum Society standards and practices.

Rationale: This will aid in the determination, by NASA, of the effective pumping speed as installed.

iii. Cryopanels shall have ease of maintenance, easily replaceable piece parts and designed for ease of inspection.

Rationale: Individual removable cryopanels makes maintenance easier to perform. Each entire panel assembly should be removable as a unit utilizing the existing chamber rail system.

iv. Cryopanel design shall implement inlet, outlet, and fin temperature instrumentation ports for both liquid nitrogen and gaseous helium for each cryopanel. Instrumentation shall be redundant. The cryopanel design shall accommodate instrumentation maintenance and replacement.

Rationale: Proper instrumentation is needed to monitor facility health and operation. Redundancy, maintenance, and replacement are requested to minimize potential facility downtime due to instrumentation failure.

v. MLI (minimum four layers) shall be used to minimize the thermal radiation from liquid nitrogen cooled surfaces that are not pass-throughs to the helium cooled surface (e.g. cryopanel edges, fluid supply and return lines, etc.).

Rationale: Best practices recommended for thermal isolation.

vi. Surface finishes, coatings, and augmentations shall be consistent with the use of the cryopanels as high vacuum pumping surfaces.

Rationale: Best practices for cryopump design.

vii. The basis for design, fabrication, examination, and testing for process system piping and components shall be ASME B31.3 Process Piping Code for Normal Fluid Service unless otherwise approved by NASA.

Rationale: Consistent with the standards applied at NASA GRC.

viii. The Cryopanels shall have a design pressure (MAWP) of 100 psig @ -320 to 100

°F for the liquid nitrogen panels and 100 psig @ -450 to 100 °F for the gaseous helium panels.

Rationale: This conforms to the liquid nitrogen and gaseous helium systems in place at VF-5.

ix. The cryopanels shall conform to all existing mechanical and electronic interfaces.

Rationale: These cryopanels are intended to be drop-in replacements for the existing NTG panels in VF-5. This will simplify the installation process.

x. The cryopanels shall be of similar outer dimensions to the NTG panels they are replacing.

Rationale: These cryopanels are intended to be drop-in replacements for the existing NTG panels in VF-5. This will simplify the installation process.

The cryopanels shall be shipped to the following.

NASA Glenn Research Center Building 301 21000 Brookpark Road Cleveland, Ohio 44135

Interfaces:

- LN2 supply: 2 ¾” Conflat

- Helium supply: 1.33” Conflat (to be confirmed)

- LN2 return: 4.5” Conflat

- Helium return: 1.33” Conflat – 2 per panel (to be confirmed)

35” 35”

Top view of bottom header of NTG’s:

LN2 supply location

North of chamber South of chamber

Type Description type T TC LN2 fin temp type T TC LN2 fin temp redundant type T TC LN2 inlet temp type T TC LN2 inlet temp redundant type T TC LN2 outlet temp type T TC LN2 outlet temp redundant type DT-670 silicon diode helium fin temp type DT-670 silicon diode helium fin temp redundant type DT-670 silicon diode helium inlet temp type DT-670 silicon diode helium inlet temp redundant type DT-670 silicon diode helium outlet temp type DT-670 silicon diode helium outlet temp redundant

1 23,4 5,6

¾ inch metal flex hose

(LN2 supply)

1-½ inch metal flex hose (LN2 supply)

½ inch OD stainless steel tube (6 helium supply and 6 helium return)

¾ inch OD stainless tube

(LN2 supply)

2 inch sch

10 stainless pipe (GN2 vent)