Laser-marker on top of the base
(http://img710.imageshack.us/img710/2381/mcclaser.jpg)
As an amateur-astronomer I often use a green 25 mW Laser to point a star at a night sky. It's very helpful.
Her's an easy Idea - let's put a laser on top of the base comm.tower.
Why?
It's an easy way for navigation, when navigation systems are off-line, during night and during dust-storms. It uses very little power. It's soo bright that you can see it during night or day! On earth, a simple hand-laser (green 25 mW) is visible....from 7 km!
On martian conditions (0.01% of the air on Earth) a little stronger laser can theoretically cover the distance of.....70 km!
That means that the laser will be seen long before you will gain eye-contact with the base itself.
Her's another cool-thing about spotter-lasers...the more dust in the air, the more bright they are (they cover less distance, but increase thei'r intensity).
All those positive aspects:
-low energy consumption
-easy and small
-wide distance covered
-work's during dust storms
make's it perfect for usage in a backup-navigation systems.
Whenever an astronaut get's lost/has no communication etc. he just look's up in the sky and notice a green-laser, and hed's toward it.
Easy, cheap and a safe idea.
(http://upload.wikimedia.org/wikipedia/commons/thumb/6/6e/Keck_laser_at_night.png/400px-Keck_laser_at_night.png) (http://scoutmaster.typepad.com/my_weblog/images/2007/03/14/green_laser.png)
http://laserpointerforums.com/attachments/f52/30220d1288634693-jetlasers-pl-c-250mw-532nm-handheld-laser-review-w-pix-6.jpg (http://laserpointerforums.com/attachments/f52/30220d1288634693-jetlasers-pl-c-250mw-532nm-handheld-laser-review-w-pix-6.jpg)