Wednesday, June 17, 2015

500 Word Response: Why Does the Aerospace Industry Use Old Stuff?

This is the first of what I'd like to make a new feature on this blog a "500 Word Response" (in reality maybe a little more or little less) to a question I hear asked about aerospace all the time. Today: why does the aerospace industry use old stuff? If you have a question you want answered, please leave a comment!

In pop culture, new 'high-tech' systems, with a vast number of bells-and-whistles, are often regarded as good and 'advanced' technology. Every time I see a Science Fiction movie it showcases all sorts of (CGI'd) aerospace tech with light-up touch screens and advanced robotics and networking. While this is fun to watch it is a solidly fantasy version of aerospace and bears no resemblance to what a real aerospace engineer will look for in a good system. Instead of looking for the most complicated possible design, a good aerospace engineer will choose the simplest, most reliable design which satisfies the requirements, typically given by the customer. If the customer wants the moon they'll get it, typically for a big price tag (F-35 anyone?) but otherwise 'extra features' and additional complexity are often and rightly seen as hindrances. The space industry takes this to the furthest extreme since you can't exactly go up and fix a malfunctioning spacecraft! So it is to be understood that any design decisions are going to be based on maximizing reliability and minimizing complexity.

So why all the old stuff? The answer is simple: heritage. How do you know, beyond any shadow of a doubt,that your systems is going to be reliable when it is flown on an actual mission? Because it has already proven itself! So long as the old system meets the requirements the argument from heritage will often (if not always) outweigh any concerns along the lines of 'but this is 1980s technology!' As with simplicity and reliability, the space industry makes this the biggest priority. That's why whenever I see someone making fun of an aerospace system which uses heritage components I know for a fact they have no real knowledge of what their talking about—heritage, i.e. old tech, is a blessing not a curse. Of course old tech is more limited than modern tech. Your smartphone could probably outperform many spacecraft computers, but can you guarantee your smartphone will work in space? Can you guarantee it will be reliable in the radiation environment? Can you guarantee there wont be some silly software or hardware error because of the unnecessary complexity? Probably not. As an aside there actually was a 'phonesat' movement a few years ago, but this came out of a new paradigm in the space industry called 'microspace', and would require a lot more words to adequately explain, and they experienced all the problems listed above.

Finally, the obvious question is how do aerospace systems improve if they only fly old tech. Again the answer is simple: new requirements are given which rule out the use of the old tech. Ultimately in any design it is the simplest system which meets all of the requirements. There is no such thing as skimping on demanded performance for the sake of simplicity—otherwise all spacecraft would be like Sputnik, a radio beacon with primary cells. Once the new tech is designed and successfully flown to meet more exacting requirements it too gains flight heritage and enters the pantheon of TRL 9 aerospace systems. 

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