In what way do planetary protection provisions affect Mars lander missions (such as Pathfinder) and Mars orbiter missions (such as Global Surveyor)?
The major impact of the planetary protection requirements on Pathfinder is that we must carefully clean the spacecraft before launch in order to keep from contaminating Mars. Although scientists now believe that it would be difficult to sustain and cultivate life on Mars, they would prefer that we not take any chances. They have developed a system for rating different missions by the potential impact that they could have. The most stringent missions are those which will be returning samples from Mars or are performing life detection experiments there. In both cases, complete sterilization is required. In our case (and MGS), we are allocated a specific number of biologic spores which are deemed acceptable. We have to clean the spacecraft (or perform mission design tricks – I write about below) to reduce the number of spores below this level (I am glad to say that we are well below the acceptable number). The only parts of the spacecraft which we actually need to clean is the part that w
