I was able to confirm Lowther worked for Zubrin. Assuming his accusations are true it indicates Zubrin either has a poor safety attitude or lacks chemical engineering expertise. Neither one equates directly with his engineering calculations on Mars Direct which are based on standard aerospace engineering formulas and his own unique application of them. It is clear in Mars Direct that he considers NASA overly conservative on safety. The prime relevance of Lowther's comments would be to call into question whether safety margins Zubrin would consider adequate would be considered adequate by most people or more importantly the astronauts willing to undertake the mission. To judge that fairly - once again we need to look at real numbers.

NASA adressed the difference of opinion on margins of safety by evolving Mars Direct into the NASA Mars Reference Missions. My own take is that Mars Direct can not be made to satisfy NASA's safety criterion, but a lot of private adventurers have faced higher risk levels and would undertake a Mars Direct type mission if launch costs were low enough. It is a testimate to the engineering expertise of Zubrin and his small band of coworkers that they were able to provide a basis for designing affordable missions to Mars as opposed to the 90 day plan derived by many more NASA engineers.

I was not able to dig deeper than confirming Lowther worked for Zubrin last weekend. Hope to do it this one, but have worked long hours this week and can't gaurantee it.

Regards,
Mark