That’s a meaningless yardstick here. People at NASA definitely thought hitting that target was achievable before the speech.
> Landing on Mars
Landing isn’t the issue. Get people there alive and having enough deltaV to get back is.
It was a mission they dedicated themselves to, and humans have this way of making things happen when we actually set our minds to tasks. A reality that's often been lost in modern times as we have mostly moved away from pursuing, let alone achieving, great things in the real world. One of the many reasons to get humans on Mars.
[1] - https://ntrs.nasa.gov/api/citations/20190002249/downloads/20...
The Apollo missions got unbelievably lucky in that none catastrophically failed despite multiple close calls. However, if you’re willing to try multiple times the odds any mission being successful is much better than every mission being successful.
IE: Six missions landed on the moon. If they each had independent 50% odds then six heads is a long way from impossible ~1.6%, but at least 1 head is quite likely ~98.4%. I doubt we would have tried for a 6th mission after 5 failures in a row, but the point is definitions of success matter a great deal here.
Similarly failures improve odds of success in the future because you learn from mistakes and success means the system is functional eliminating some risks.
On that specific launch, which is another way of saying they believed the project had a very good chance of having someone walking on the moon. Failure there wouldn’t even mean people died, just that they didn’t walk on the moon and then safely get back on that mission.
Had the Apollo missions failed you would obviously be arguing, using the exact same data, that they 'knew they never had a chance.'
No, an earlier post argued that 6 successes doesn’t mean the odds of success on every mission was high. “Got unbelievably lucky” https://news.ycombinator.com/item?id=43130343
The exact opposite position after 6 failures would be that the odds were good that at least 1 mission would have succeeded.
Obviously, things aren’t actually completely independent, but 6 lunar landings could have successfully been completed with a huge range of different odds. 50% odds of success on the first launch isn’t inconsistent with 6 successful launches or 6 failures, it’s just not enough data to really narrow things down.
Again, I’m addressing the point “getting them there alive”. Unquestionably, we know how to get crew to Mars alive, and even for the full mission duration, radiation isn’t even in the top 10 of the hazards that could actually kill them during the mission. (It’s a long term hazard, comparable to lung cancer if you’re a cigarette smoker.)
Note that the magnetic field only deflects lower energy galactic cosmic rays which have a lower gyro radius than the real whoppers. The magnetic field is less important to overall radiation shielding than the earth’s atmosphere.
On a long-stay Mars mission, that adds up to 12-18 times the accumulated GCR exposure compared to a six-month ISS increment.
In fact, look at Table 2. It shows that at ISS, the dose from the SAA is about the same as the GCR dose, so by ignoring trapped radiation, you’re manipulating the result by a factor of 2.
It’s possible people spending significant time on the surface of mars would recover, but that’s more speculation than proven.
Going beyond that is not really meaningful since that's far longer than any normal transit to or from Mars, which is the immediate target.
Living on mars at 38% earths gravity is believed to make things worse over time, so no you can’t just consider transit times independently. On arrival they would likely be fine inside a habitat. But trying to walk around in an Apollo 11 era 180 lb pressure suit in 38% gravity would be nearly as strenuous as walking around on earth and we’d like them to be able to work not just take a few steps and sit down. It’s possible to reduce that weight, but needing to carry oxygen tanks means there’s quickly a tradeoff between lighter weight and less time outside.
Now, for an extremely brief touch Mars and come back while burning a huge amount of fuel to make a shorter trip sure they’ll survive. But start talking a 3 year mission and things don’t look good.
Back on Mars they'll be able to quickly regain their motor skills coordination, as well as strength/bone density. So it will be effectively equivalent to Earth in this regard - actually it will be even better than Earth because the reduced gravity will probably send the overall adjustment time down from a couple of days to a couple of hours, especially with a normal duration transit.
> stuck on the ISS for going on 9 months now
Stick right next to earth and all the medical care they would want on landing. That’s the difference they don’t need to be functional on earth.
> regain motor skills and coordinate
Meaning they’re nearly helpless for a significant period on landing. That’s a massive safety concern and limitation on mission profile.
> as well as strength/bone density
There’s serious concern around retaining let along regaining bone density on Mars. 38% g isn’t a well studied environment here but it’s a long way from earth and likely to result in significant bone loss up to a point. Meaning their trip back is now significantly more risky.