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Do you know these time saving aspects, regarding Space Requirements and test criteria?

Written by: Craig Haywood, 
Senior Technical Advisor

Plan ahead for material availability, know your spec release requirements and look into what test criteria your add-ons demand. Read the advice from our Senior Technical Advisor Craig Haywood, an expert on Space Requirements and production.

We are in unsettled times. Copper and component shortages, Covid disruption and now laminate lead times being extended for various reasons.
What can we do to minimise disruption in the PCB design/ordering phase in the Space sector including release requirements to ECSS-Q-ST-70-60C or IPC 6012(ES)?
Plan ahead as much as possible to allow time for material availability/delivery options and know your spec release requirements so time for lab tests/coupon verification is considered for the lead time.  

Less stringent Space Rules
With the Newspace/Cubesat pcbs a lot of boards can be made to less stringent space rules i.e. no compliance required to ECSS, so smaller tracks/gaps/finishes are allowed. We then see requests for manufacture to IPC standards but with add ons – e.g. high resistance test to ECSS-Q-ST-70-60C or MRR approval even though these don’t fall within IPC criteria. Sometimes this is dictated by the end customer requirements but even they may not know what the full spec release requires. 

Bear in mind that spec release + add-ons is invariably going to lead to an increase in cost and lead times. 

More relevant is knowing what test criteria you require when you specify these add-ons. As an example, it’s ok saying we want IST coupon test sampling with this order but do you know the test parameters – are ECSS-Q-ST-70-60C requirements ok or do you need to set a higher/lower number of cycles for pass rate? The more info that can be supplied in the data file documentation or received at quote will aid the smooth flow of the RFQ process. 

Below are some guidelines for additional test requirements.

ECSS-Q-ST-70-60 C  – IST coupon testing is mandatory for the following aspects of design. *

  1. Any PCB with ≥ 0.3 mm in Z-direction as-designed insulation distance of no-flow prepreg or 85NT; this is related to the total thickness in the stack up and not just in 1 area of the stack. Given that prepregs have to be 2ply minimum and the thinnest combination of this is 0.15mm you can read this as any Rigid flex will require IST testing.
  2. Epoxy PCB with ≥ 12 copper layers; 
  3. Rigid-flex PCB with one or more of the following aspects: (a) ≥ 12 copper layers, or (b) ≥ 2 flex laminates, or (c) asymmetric build-up or asymmetric lamination; As above – all rigid flex will require IST testing
  4. HDI PCB with microvias or with aspect ratio > 7

Time saving aspects to remember
At the start of the tooling process the coupons will have to be created which is a sub- contract process so allow up to 2 weeks for this.
If the design is ready in advance of the quote it is possible to obtain the coupons directly from PWB – if the coupons are ready and supplied with the pcb data set it will save time in the tooling process. 

If it’s an ECSS-Q-70-60C order, allow 10-15 days for MRR/tooling completion. Board acceptance is based on successful test results at the end of pcb manufacturing – typically you will need up to 4 weeks test time. There is no deviation requirement to this unless approved by ESA and then a waiver will be produced as this will be classed as an exception to the standards. 

IPC 6012ES – D coupons are required for this aspect of the spec, the requirement can be waived with customer authorisation but this needs to be discussed at RFQ stage. D coupons are similar to IST in that the testing is currently a subcontract process. Unlike IST, D coupons can be created by the manufacturers during the tooling stage but have additional costs and lead times – these will be confirmed at quote stage. 

If you have additional requirements to your spec release, please try to find out as much information as possible and then speak to us regarding these so we can advise capabilities. This also applies to material lead times where we can try and source the best options available to meet your product demands.

PCBs for Space might not be Rocket Science. However knowledge of the specific demands for ESA approved PCBs, reliability of materials and technologies offer a huge advantage. We have “been” to space for years, give us a call when you are planning your next space product.

*IST test requirements, credit ESA requirements.

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Grensen 12, N-0159 Oslo
Norway (Google maps)

Phone: +47 22 09 87 00
Fax: +47 22 22 03 25
inbox@elmatica.com

Org.nr.: 921 513 240 /
DUNS nr. 519297139

Grensen 12, N-0159 Oslo
Norway (Google maps)

Phone: +47 22 09 87 00
Fax: +47 22 22 03 25
inbox@elmatica.com

Org.nr.: 921 513 240 /
DUNS nr. 519297139

Part of NCAB Group

Grensen 12, N-0159 Oslo
Norway (Google maps)

Phone: +47 22 09 87 00
Fax: +47 22 22 03 25
inbox@elmatica.com

Org.nr.: 921 513 240 /
DUNS nr. 519297139

Grensen 12, N-0159 Oslo
Norway (Google maps)

Phone: +47 22 09 87 00
Fax: +47 22 22 03 25
inbox@elmatica.com

Org.nr.: 921 513 240 /
DUNS nr. 519297139

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