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.
