While inventorying all my electronic parts, I stumbled across a few old forgotten parts from a fairly old project which was designed according to military standards. The ICs are JM38510/10901BPA, which are military grade 555 Timer ICs.
What many people don’t realize, most ‘regular’ parts such as ICs and microcontrollers may not be used in military, aviation and / or aerospace applications without further ado. I often see designs intended to be used in space, such as CubeSats, designed by universities which use off-the-shelf parts in their circuits and I can’t help but shake my head.
Almost every datasheet for electronic components contains a paragraph like this:
[Manufacturer]’s products are not specifically designed for Military, Aviation, Aerospace, Life-dependant Medical applications or any application requiring high reliability where component failure could result in loss of life and/or property. For applications requiring high reliability and/or presenting an extreme operating environment, written consent and authorization from [Manufacturer] Corporation is required.
Of course this is not a straight out prohibition. It is merely the manufacturers statement that they will not be liable if you chose to use off-the-shelf parts in your design anyway. But if I design a military or aerospace application I want the manufacturer of the parts to be liable in case of a catastrophic failure. Especially projects on a tight budget need this extra safety line on the liability level.
The rules for parts increases from off-the-shelf ‘standard’ parts with the least over military / avionics with medium and aerospace with the tightest specifications. Military parts have a whole catalog of extra criteria such as extended temperature range (–55°C to 125°C) and other environmental parameters. The primary difference between regular military parts and parts for aerospace is the heightened requirement for radiation tolerance. If you send your regular 4000-series CMOS up in space, there is a chance that the ionizing radiation might trigger the gates inside in an unwanted manner.
Usually, all manufacturers offer specially rated parts for military and aerospace applications. The most important step in the design phase is to ensure a certain part is available for the intended environment. For instance, it’s no problem to send a classic NE555 into outer-space as long as there is a model available which is rated for space.
If we take a look at Texas Instrument’s webpage and look for the SE555 (NE555 with extended temperature range) , we see this:
Texas instruments offers the SE555M  for military applications and the SE555-SP  for space applications. With that in mind, we can go ahead and design a NE55 based circuit and send it into space.
Parts with special ratings are of course a little bit more expensive. The regular SE555 costs about 2.35 per piece. That is an increase of about 1678 %. A different sub-type of the SE555M, the JM38510/10901BPA that I found in my boxes, costs even more – 10 000 to $ 20 000 for a CubeSat launch, please don’t start using low-budget parts in your design.