PC: Mars flyby instead of Lunar Landing?

OTL NASA did develop plans for Mars and Venus flybys using Apollo hardware, scheduled to be launched in the mid to late 1970s.

So, perhaps instead of pledging to land a man on the moon and return him safely to Earth by the end of the decade, Kennedy pledges to send astronausts on a flyby mission to Mars by, say, America's bicentenniel.

Is such a program plausible, and, if so, could these eaarly flybys lead to further manned exploration of Mars?
 
A flyby with a mission duration of months as a primary goal has a serious issue when they're only just progressing beyond single-man missions with durations measured in hours. To even prove it's physiologically possible, they'd need to do a series of station flights beforehand--so now we're talking about a series of station flights beforehand, something a lot more complicated to explain and less immediate. I think it'd be doable by 1976--but now Kennedy's making a pledge about something 15 years in the future. That really limits it as a political gesture to respond to the Soviet's apparent advantages in space.
 
Not really plausible, unless you want the guys to come back dead or dying of radiation poisoning, and that's if you can get a ship built that would keep going for that long.
 
Why? For one landing on the Moon was logical step from orbital flights. Going for Mars/Venus flybys is taking things so far forward it makes little sense. For two planetary flyby simply doesn't have the visual impact and hence propaganda value as sending man on the Moon, showing him jump around and come back to tell about it.

Only way US would think about it would be if SU got man on the Moon first and US had to do something of good propaganda value. And even then US would first send man on the Moon with a twist that they did something better than SU, like how NASA pointed out their first man in space did three orbits and had more control over his craft than Gagarin.
 
OTL NASA did develop plans for Mars and Venus flybys using Apollo hardware, scheduled to be launched in the mid to late 1970s.

So, perhaps instead of pledging to land a man on the moon and return him safely to Earth by the end of the decade, Kennedy pledges to send astronausts on a flyby mission to Mars by, say, America's bicentenniel.

Is such a program plausible, and, if so, could these eaarly flybys lead to further manned exploration of Mars?

As others have said they had no experience of deep space flight (and still don't). They would be dead from radiation from solar flares as well as normal deep space radiation. In addition missions to Mars didn't have a good track record even with unmanned spacecraft and the prospect of dead astronauts floating for all eternity around Mars would cause too much embarrassment.

Also IMO Kennedy isn't going to pledge to a mission that would take place long after he's gone. Also they wouldn't have anything to show the world except fly a long way in a big circle. No flags, no footprints no pictures of astronauts on the surface of the moon. Just some guys floating in a space capsulse with a view of Mars from the window.
 
I was under the impression that one of the goals of Skylab missions was to see if people could stay in space for the sort of prolonged periods that a Mars mission would need, both the people themselves and the sort of spacecraft they'd need. This was in the same vien as the Gemini missions proving the sorts off things the moon mission would require: orbital maneauvre, docking, EVA, prolonged (at the time) spaceflight.

As such you can't have a Mars flyby without some sort of long duration flight in the vien of Skylab and more.
 
Not really plausible, unless you want the guys to come back dead or dying of radiation poisoning, and that's if you can get a ship built that would keep going for that long.

The risks from radiation were known by 1965 and protectives measures like protecting the core of the spacecraft would be easy to implement.

Weightlessness can be prevented if the spacecraft rotate along its central axis or if it is propelled.
 
What spacecraft was plausible in about 1970 that could be rotated around it's central axis to create gravity? The only experiment I know of in that period was a Gemini and agenda linked by a tether which managed to register a smidgin of gravity for a tiny amount of time.
 
What spacecraft was plausible in about 1970 that could be rotated around it's central axis to create gravity? The only experiment I know of in that period was a Gemini and agenda linked by a tether which managed to register a smidgin of gravity for a tiny amount of time.

Unfortunately, it looks like the JAG Flyby mission spacecraft does not rotate.:( This is especially bad since the crew would be spending 661 days in space. The longest anyone has currently been in space is 438 days, so I don't know what kind of effects that would have on the crew.
 
What spacecraft was plausible in about 1970 that could be rotated around it's central axis to create gravity? The only experiment I know of in that period was a Gemini and agenda linked by a tether which managed to register a smidgin of gravity for a tiny amount of time.
Part of the issue is that even today we don't know the minimum amount of gravity required to mitigate the medical risks (bone loss like hyperosteoporosis, muscular degeneration, deformation of the eyes, all kinds of strange stuff), nor do we really have a solid idea of the upper limit to human's tolerance of spin rates for a habitat.* These two characteristics would directly define the size of the spin habitat. Is it 1G and 3 RPM? Then you need a radius of 100 meters. Is it 0.16 G (~lunar) and 6 RPM? In that case, you only need an 8 meter radius. We have exactly two data points: "zero gravity is kinda sucky over periods measured in months to years" and "full gravity eventually causes back problems and arthritis." Proposing a Mars flyby without much better data is incredibly risky.

*I consider the grounding of the Centrifuge Accomadations Module, an ISS lab that would have featured a 2.5m diameter rotor one of the major failings of the station's construction--it was being built, but was cancelled after Columbia to save funds and compress the "completion" timeline.
 
The risks from radiation were known by 1965 and protectives measures like protecting the core of the spacecraft would be easy to implement.
Except that the stuff that best protects agains gamma radiation is terrible at protecting against bremsstrahlung radiation. Amorphous carbon would seem a decent go-between in this case but the problem is lifting a sufficiently big mass to shield all the habitable areas of a spacecraft.
 
Except that the stuff that best protects agains gamma radiation is terrible at protecting against bremsstrahlung radiation. Amorphous carbon would seem a decent go-between in this case but the problem is lifting a sufficiently big mass to shield all the habitable areas of a spacecraft.

Quite. Increasing the wall thickness slightly INCREASES the total radiation dose as high energy particles generate gamma in the walls, the bremsstrahlug matt mention.

Putting the habitable areas INSIDE fuel tanks is one theoretical possibility, but ,,easy to implement,, is just plain wrong.
 
Quite. Increasing the wall thickness slightly INCREASES the total radiation dose as high energy particles generate gamma in the walls, the bremsstrahlug matt mention.

Putting the habitable areas INSIDE fuel tanks is one theoretical possibility, but ,,easy to implement,, is just plain wrong.

Easy to implement if you just throw mass at the problem (seriously, throw enough mass at anything in aerospace and you can generally take care of any issues). Of course...the problem is the correspondingly enormous mass of propellant you'll need and the beyond correspondingly absurd budget you'll need just to launch all of your radiation shielding, to say nothing of the ship...

Mars flyby instead of lunar landing? No, it's just way too much of a jump from Earth orbit activity. If we were on a moon orbiting a big gas giant, and "Mars" was another moon, then it might make sense (we wouldn't have a moon in that case anyways), but that's mostly because all the real challenges associated with deep-space flights would be gone.

And more so, while now most people would consider such a flight physiologically possible, if risky, back then there were some who seriously questioned the ability of humans to survive much shorter flights...after Biosatellite 3 failed, there were some who questioned the practicality of Skylab!
 
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