There's a lot of common ground between the two plans but all the focus is, of course, on the differences. Dr Zubrin can't be happy that NASA is doing work that supports his plan, only being appointed the Space Czar will do.
- "Mars as destination" - Mars is the declared destination of both programs. That's a big deal, there's lots of other places that could be the destination. Considering that NASA has long been banned from considering Mars the destination, that's something worth celebrating.
- Nuclear Power qualified for use in space - Both plans make critical use of fission nuclear power.
- Entry, Descent and Landing in the Mars atmosphere - Landing on Mars is hard and precision landing of large payloads (double digit tons) is required for any human Mars program.
- In-situ utilization of the Mars atmosphere for a preplaced ascent stage - This is a Zubrin original idea that has been whole-heartedly adopted by NASA.
- Long stays for conjunction - Zubin famously made the case for staying on the Mars surface for long stays to reduce the duration of transit to months instead of years, again adopted by NASA as a standard.
But there are differences and, although they shouldn't be focused on they should be acknowledged.Disagreement
- Mission mode - obviously, Mars Direct is a direct mode, whereas the new plan (and most other Mars plans) leaves from LEO. The future NASA plans also call for aerobraking into Mars orbit.
- Zero-g mitigation - Mars Direct famously proposed the use of a tethered spinning habitat, a risky proposition. Whereas the future NASA plan is what I call Charlie Bolden's Magic Rocket - reducing the transit time so zero-g isn't a major issue.
- Radiation mitigation - the reduction in transit time also helps here. The Mars Direct plan has always been a combination of crew selection (all smokers, make em quit, ha ha), shielding with supplies (there's not enough and as you eat them..) and just outright denial.
But today's session will probably focus on commercial crew and asteroid missions.. in other, words, irrelevant politics.