NASA's Planned Venus Mission Would Have Put Astronauts In A Fuel Tank

Venus has never been really high on us Earth-people’s priority list for exploration or colonization, mostly because as a species we tend to be big candy-asses when it comes to sulfuric acid rain. But that doesn’t mean it’s not worth exploring, and plans have been made to do so — even ones that would stick astronauts in the fuel tank for the trip.

Of course, I’m being a little provocative by describing it that way, but, really, that’s what the plan was — and it’s actually a fantastic idea. The basic concept is known as the wet workshop, and it’s essentially the idea that a rocket’s fuel tank, once drained of fuel, would actually make a pretty fantastic habitation module — and it’s already where it needs to be, with nothing extra or new to haul into space.


See, for liquid-fueled rockets, most of the actual volume of the rocket is taken up by massive fuel and oxidizer tanks. Instead of just sending these tank sections of the rocket tumbling to their destruction in the atmosphere, why not just vent the remaining fuel from them and then move in life support and other equipment — and maybe some throw pillows — and turn these massive volumes into usable, habitable space?

It’s a really compelling idea, and it’s been considered many times, but never yet actually tried, due to several issues. First, there’s the difficulty of actually outfitting the tanks, which isn’t as easy as you’d think — you have to have some small module to get the equipment up there (or another vehicle to transport it and dock to the module), you need hatches to get into the module to outfit it — none of these are insurmountable at all, but they do need to be considered.

The idea is so incredibly appealing and efficient it just won’t go away. Skylab, the first American space station, was almost to be done this way, but a last minute change of launcher from the Saturn IB to the Saturn V meant that a whole fuel tank section wouldn’t need fuel, anyway, so Skylab became a simple dry workshop — similar idea of re-purposing a former fuel tank section, but no need to actually fuel it up.


One of the best ways to see how this would have worked is to look at the cancelled manned Venus orbital mission NASA was planning in the 1960s, as a follow-up to the Apollo moon landings and using already-developed Apollo hardware.


See, back when the Apollo missions were just being planned, before we’d landed on the moon and then eventually became, incredibly, jaded to the idea that we could, you know, land on the fucking moon, all manner of follow-up missions to the Apollo moon landing were planned. These follow-up missions used variations of the Apollo hardware developed for the moon landings, reconfigured in some very clever ways.

The Venus mission, officially known as the Manned Venus Flyby, is one of the most interesting re-workings of Apollo hardware of all the Apollo Application Program (AAP, what these after-Apollo missions were called) missions.


Using the same Saturn 5 rocket to launch as the moon landings, the Venus-specific spacecraft also used the same basic Apollo command module (the conical return capsule). The Apollo service module was modified to include two motors from the original lunar lander instead of the larger Apollo service module motor, both to save space and provide some redundancy.

In place of the Lunar Module used on the lunar landing missions, there was a module called the Environmental Service Module (ESM) that contained the life support equipment and other cargo needed to outfit the final rocket stage as a habitation module — that wet workshop we talked about earlier. Once that final rocket stage sent the spacecraft en route to Venus — a trip that would take 123 days — the leftover fuel was vented and the astronauts could move in.


The living equipment in the habitation module was also pretty revolutionary, which makes sense, given the long duration of the mission:

To keep them occupied otherwise their habitation capsule would have been outfitted with a small movie screen (to show 2 kilograms of movies allowed), and a “viscous damper exercycle/g-conditioner”. The crew would also be allowed 1.5 kilograms of recorded music, 1 kilogram of games, and 9 kilograms of reading material.


I’m pretty sure that’s the first instance ever of a spaceship movie theater, as well. Also, measuring movies in kilograms is a pretty mind-bending concept on its own.

Part of the wet workshop module would have been a ‘hangar’ for an impressive collection of probes to send to Venus, as well:

▪ Six atmospheric probes, which would enter the atmosphere at six locations: the planet’s solar and anti-solar points, its terminator and equator, and the middle of the light and dark sides. They would drop in ballistically and try to determine how Venus’ atmosphere increased in density the closer one got to the surface.

▪ Four meteorological balloon probes. They would float in the atmosphere and try to learn how the Venusian atmosphere circulated as well as study smaller-scale winds.

▪ Two “crash-landing” probes that would try to photograph the surface on the way down, much like Rangers 7, 8, and 9 did with the Moon.

▪ Two soft-landers that would take surface photographs, examine the soil, and measure Venusian weather.


The physics of the mission only allowed for a Venus flyby as opposed to remaining in orbit, but the spacecraft would still come within 6200 km of the planet on March 3, 1974. All that travel for just one day close to Venus, but it would be a hell of a day, with probes dropping and side-scan radar mapping as much of the planet as possible. After that big day, it would take 273 days to get back to Earth, for a grand total of 396 days. That’s a hell of a mission.


The mission, as we know, never happened, for a variety of reasons. The most obvious one to most of you reading this now is that the mission is a hell of a lot of travel time for not much time at Venus, and if most of the real science would be handled by the probes, what do we need the astronauts for at all? It’s a hard point to refute, at least in this context.

Also, and more tragically, the entire Apollo Applications Program was cancelled, which effectively stalled all the momentum NASA had made in developing the Apollo program.


On the brighter side, it may be good that the mission was cancelled, because, really, there’s still a lot we didn’t know about the sun:

On July 5-6, 1974 the Earth was hit by a big coronal mass ejection (CME), a storm of electrons and protons thrown off of the Sun. People down on Earth were protected by the planet’s magnetic field, as usual, but the astronauts coming back from Venus wouldn’t have been so lucky. Their line to the Sun was several degrees off from the Earth’s (at the time they would have actually looped out past Earth as their trajectory slowly took them back home), but CMEs can cover quite a bit of space. Had the mission actually flown, the astronauts on-board may well have died of radiation sickness after being hit with more (and more energetic) solar protons than their spacecraft was built to handle.


Yeah, that could have been a tragedy and a PR nightmare, our triumphant Venusian astronauts dying en route back home.

Looking back at these missions is still fascinating, because it really does show just how much could have been done with the hardware and technology we had back in the 1960s and 1970s — and a bothersome reminder of how little we’re actually doing now.


But I’m still hopeful; if nothing else, we can now cram a hell of a lot more movies into 2 kg than we could back then.

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