LPLV_Question_and_Answers_Final.pdf

EUROPA LOW PRESSURE LATCH VALVE

Request for Proposal (RFP) Solicitation No. 80GSFC18R0004

QUESTIONS & ANSWERS

Documents Referenced:

EUROPA-PROP-SPEC-0006, Revision - , EUROPA Clipper Propulsion, Code 597, Low

Pressure Latch Valve Specification

EUROPA-PROP-SOW-0006, Revision - EUROPA Clipper Propulsion, Code 597, Low Pressure

Latch Valve (LPLV), Statement of Work

Q1:

Specification paragraph 3.2.6, Filtration:

Would use of the 42-micron filter be acceptable in place of the 25-micron filter required as specified in 3.2.6?

A1:

Reference Section 3.2.6 “Filtration” in the Specs which states: “The latch valve shall have an inlet filter with a filtration rating greater than or equal to 25 microns absolute.”

Q2:

Specification paragraph 6.1.7, Assembly Outgassing: If the standard outgassing data were not sufficient, would NASA be willing to perform this assessment on a flight unit? If an outage exists, could this be covered on a MUA or waiver?

A2: Heritage outgassing assessment can be assumed for this test requirement. Vendor shall provide material data. NASA will evaluate material outgassing total. Response should be noted in compliance matrix and may be accepted as an exception with COR approval.

Q3: Specification paragraph 6.1, Surface Contamination & Planetary Protection, and SOW paragraph 5.4, Planetary Protection: Are planetary protection requirements truly required at component level or can this be accomplished by NASA at a higher level?

A3: Planetary protection is required at a component level and cannot be accomplished at a higher level. Parameters are provided in a table 2 “HMR Times & Temperatures “in the statement of work. The vendor is to choose one of these, based on the limits of the hardware that the vendor may know from material compatibility.

Q4:

Specification, multiple references to an “opening and closing coil”: The heritage Latch Valve design utilizes redundant motor coils (4 windings; 2 opening, 2 closing) to provide electrical redundancy for increased reliability. Does this application require single opening and closing coils or redundant opening and closing coils?

A4:

Single or redundant opening and closing coils both meet requirements.

Q5:

Specification paragraph 4.3.2 Fastener Accessibility: Is it acceptable that the mounting holes are obscured from the top of the valve, but sufficient clearance is given to allow fastener mounting?

A5: Vendor is encouraged to respond to requirements as written, but include cost and schedule impacts, if applicable.

Q6: SOW paragraph 5.1.1 Materials Selection Requirements: Is it acceptable for the valve to use magnetic materials?

A6:

Magnetic materials will require an MUA to be approved by the NASA COR. Magnetic materials for valves have been approved and accepted by past NASA missions, however, blanket approval cannot be given.

Q7: SOW paragraph 7.4.1 Workmanship Requirements: J-STD-001ES (Space Addendum) requires special provisions for wire handling (requirements pertaining to a Red Plague Control

Plan for shipping, storage, assembly).

Is there an option for a waiver for this requirement for the wires that are soldered to the microswitch and connector?

A7:

Red Plague requirements apply to silver plated wire, for example, 22759 stranded. This would include wire that is soldered to the microswitch and connector. The requirement to have a plan applies only to the vendor that hooks up the switches and connectors, not the coil supplier.

Q8:

SOW paragraph 5.2 EEE Parts Requirements:

•Does this section mean that all outgassing, flammability and qualification test data for all parts used in the coil assembly must be compliant?

•Wire derating: Does this requirement apply to the valve, since the required test parameters in the spec will result in currents greater than what is listed in Table 4 of section W1 of EEE-INST-

002?

A8:

The standard qualification processes of the vendor are acceptable for the magnetic assembly of the valve and coil, and for any components not covered by the applicable sections of EEE-INST-

002. Component testing is required for any components covered by applicable sections of EEE-

INST-002 (including switches, connectors, and wire) before they become part of the assembly.

Waivers may be granted by the COR for pulsed currents in excess of Table 4A of Section W1 of

EEE-INST-002. Such waivers should be backed by thermal analysis that shows comfortable margin between the worst case predicted, instantaneous temperatures and the ratings of the wire and insulation.

Q9:

3.6.2 Soft Seat Material

What information can NASA provide the FEP and PFA materials with respect to past use in space propulsion applications, especially with respect to swell and life after contact with fuel and oxidizer?

A9:

NASA has determined acceptability of FEP and PFA materials but cannot provide data at this time. Rationale for the radiation requirement is provided in the 3.6.1 Radiation Dosage of the specification. The material needs to meet radiation and capability combined effects. See

RADIATION EFFECTS DESIGN HANDBOOK Section 3. Electrical Insulating Materials and

Capacitors by C. L. Hunks and D. J. Hunzmun