Mars is a dusty planet. Here is some info on the dust: Nasa dust

As part of the instrument package, it would be good to have a dust sensor to measure the actual amount of dust suspended in the air. Dust is bad for mechanical sensors and could play havoc on solar power generation as well.

To measure dust, I selected the Sparkfun Optical Dust Sensor – GP2Y1010AU0F. Here is the vendor link: sensor

As of 3/1/2017 I have not connected this sensor due to cabling and time issues.

Here is the datasheet: sparkfun dust sensor gp2y1010au_e

The features of this device include:

• power consumption (20mA max, 11mA typical)
• powered with up to 7VDC
• output of the sensor is an analog voltage proportional to the measured dust density
• sensitivity of 0.5V/0.1mg/m³
• 6-pin, 1.5mm pitch connector

When/if you buy one of these, make sure you buy the special connector for the cable. Also, buy enough of the little clips for the pins. I only bought one and so cannot connect at this time using their connector. I may just carefully solder wires onto the board and make my own cable.

The potential downsides to this device include the cable, fairly large power requirements (it uses an IR led when operating), and the large size of the unit. It needs to be connected to an analog input port and may need some discretes to make it work.  It may also need some calibration.