Say you want to send a satellite from Earth — all the way to Mars! Now, it's got
to get there without running out of gas, malfunctioning, or otherwise causing
trouble. And if that's not enough, it's also got to sample things and send the
results back to Earth. Now, that being said, it seems obvious that you can't
just go building satellites all willy-nilly. Satellites are expensive little
things, and you need to make sure that all your plans will work before you run
out of money. This is why, before building anything, scientists and engineers
hold what looks like an endless series of meetings, phone calls, telecons,
tag-ups, and get-togethers, culminating in what's known as a design review.
Take, for example, the MAVEN spacecraft.
Now, it's a great idea for a satellite — one that studies the upper atmosphere
of Mars — but, of course, it's not good enough just to have a great idea. It
needs to be reviewed, just like anything else. At this review, a whole lot of
other smart people take a good, long look at the design, and hopefully, they
decide they like it. If all goes well, they think that everything makes sense,
the budget is in line, there isn't substantial risk involved, and now, we can
move on to the next step. And once you've finished, you'll finally be able to
get all the data you wanted...without any trouble.