They haven't sent any life detecting instruments to mars since 1975 with the two Viking missions ! NASA continues to send landers and orbiters to mars that conduct the same old redundant geological surveys and weather reports in an imagined dream that we will be sending a manned mission there some time in the near future. That's NOT going to happen any time soon for various reasons, radiation being the biggest one.
Why not build two unmanned vehicles that can do flyby's of all the planets and moons and deploy micro-landers at various locations with the capability of determining the presence of life and radioing back the data ? We have the technology and we can conduct a half decent survey of our entire solar system in this way in probably as little 20 years or so.
Beats what we're doing now !