The UK head branch of the 'Students for the Exploration and Development of Space' (SEDS) has announced the '
Lunar Rover Design Competition' for this year! An absolutely awesome challenge to take, our University SEDS branch has now started their entry.
Unsurprisingly my fellow blog masters and I ended up in a team dealing with communications (and an obvious wink wink that we may be about to take over electronics, power and control as well).
So, what are the problems facing your lovely electronics if they were lucky enough to go to space, and the moon in particular:
1. This is the biggest: RADIATION. Down here on lovely Earth we have a nice blanket called the atmosphere blocking out all the horrible energy the sun (and space in general) likes to throw around in the form of radiation, both EM and particulate. In space these have a nasty habit of interacting with our electronics, changing logic states, causing voltage levels to fluctuate and so on. There are a whole bunch of fancy names for this, the big ones are 'Single Event Effects' where a single element of radiation causes unpredicted behaviour in our system (like changing a logic value), and the alternative measured with the 'Total Ionising Dose' which refers to transistors becoming unusable after their oxide layers are saturated with radiation induced holes over time. I think this is a really cool area to look at so I will no doubt talk about it at length later.
2.Getting there. So even if we let someone else do the whole rocket/launcher bit, we still have to deal with the environment experienced during launch. This is so important that they are actually making the rovers undergo a vibration test for the competition. The effects of this are fairly intuitive, any dodgy solder joints or loose connections will just wobble loose and ruin our day.
3. Temperature. The other lovely thing about our atmosphere is that it keeps everything at about the same temperature (although during winter it doesn't feel like it). To put it into perspective the maximum temperature range at Kew in London (record high to record low) is around 29°C. On the moon this is
290°C. Additionally, once we are in the vacuum there is no lovely air convection to take your heat away. This all adds up to produce concerns which we really don't have to worry about on the ground such as conductance changes and material fatigue (due to heat expensions and contractions.
4. They are a long way away. If your electronics/electrical systems fail terminally then you can't go and kick them (or the equivalent) until they restart, the
Hubble Space Telescope being a notable exception. Failures in space need to be dealt with before they happen usually by exhaustive analysis and sneaky design.
5. Dust. Moon dust is pointy, with only solar radiation to break it down grains, unlike the many weathering effects we have down here, they retain sharp edges which can be really rather problematic when those edges start to point at your electro mechanical components.
I have not even scratched the surface here, I imagine that rewriting this article in 8 months time would be an amusing exercise after actually facing these problems.
