In the legal aspect there are multiple considerations to take into account, the first I’ve researched about is the PCB quality production.

[Standard Quality Assurance Requirements for Printed Circuit Boards] (https://s3vi.ndc.nasa.gov/ssri-kb/static/resources/gsfc-std-8001.pdf)

This document contains quality characteristicas required by NASA Standards.

Some characteristics are:

• IPC-6012 Space Addendum, Space and Military Avionics Applications Addendum to IPC-6012, Qualification and Performance Specification for Rigid Printed Boards
• IPC-6013, Qualification and Performance Specification for Flexible Printed Boards
• IPC-6015, Qualification and Performance Specification for Organic Multichip Module (MCM-L) Mounting and Interconnecting Structures
• IPC-6018 Space Addendum, Space and Military Avionics Applications Addendum to IPC-6018, Qualification and Performance Specification for High Frequency (Microwave) Printed Boards

Additionally there are some more requirements.

• Board Markings
  • All traceability markings of PCBs and coupons shouldbe non-conductive white epoxy base ink, low outgassing formulation (1% TML / 0.1% CVCM IAW ASTM E595).
  • Labels shall not be used to identify flight boards or coupons.
  • Solder on copper for marking is not preferred.
• Etchback
  • Negative etchback shall not be allowed unless evidence is submitted, that is reviewed and approved by the Project CSOin consultation with the MPCB CRAE, demonstratingthat residue is sufficiently controlled in the desmearing process and/or interconnect stress testing indicates that the finished boards will not contain trapped residues that limit service life.
  • When no etchback condition is specified on the drawing, criteria for smear removal shall be applied for product acceptance.
• Solderability
  • Surface and plated-through-hole solderability shall be evaluated in accordance with J-STD-003, Category 2.