II-VI Marlow Space Qualiﬁcation Process For Thermoelectric Coolers

II-VI Marlow has developed processes and procedures for 35+ years that have been used to design, fabricate

and test thermoelectric coolers (TECs) for space applications. The Space Qualiﬁcation Procedure consists of

the following elements:

• TEC design and documentation

• TE material processing

• TEC assembly

• TEC testing

The output of these processes is TECs that fall into three categories:

1. Engineering Units: Used by the customer to validate thermal performance, develop assembly

processes, and conﬁrm ﬁt. Additional testing for space applications is not performed.

2. Flight Units: These are Engineering Units that have gone thru additional non-destructive testing

agreed to by the customer, commonly referred to as Acceptance Testing. These TECs are suitable

for flight.

3. Qualiﬁcation Units: These are Flight Units that go thru additional life testing that is considered to

be destructive testing. The data generated is shared with the customer. The TECs can be delivered

to the customer if desired for archival purposes.

TE DESIGN AND DOCUMENTATION

For all space applications, the design parameters and boundary conditions are carefully discussed with the

customer. II-VI Marlow then assists in the preparation of the speciﬁcations and the Statement of Work. After

II-VI Marlow is placed under contract, the design and documentation are ﬁnalized. Design reviews are

conducted to conﬁrm that the customer agrees with the ﬁnal design according to their expectations.

Space qualiﬁed TEC applications can use Commercial Off-The-Shelf (COTS) TECs. For these applications, the

customer requirements are evaluated and a COTS recommendation will be made, if appropriate. The COTS

parts can go through the same testing as custom designs to become space qualiﬁed.

Frequently, custom designs will be required to meet the speciﬁc requirements. A custom design will be

dedicated to a speciﬁc customer and will be ‘owned’ by the customer. The custom design will be built in our

U.S. based facility, and will then go through the testing required to become space qualiﬁed.

TE MATERIAL PROCESSING

For Space Applications, II-VI Marlow has developed TE material processing procedures with additional

inspection steps and a higher level of documentation control as compared to our standard procedures. This

documentation system assures tighter control on the processing standards and additional testing on

individual lots of materials.

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