As a lot of space geeks I am a big fan of Andy Weirs book the Martian. In an interview he explained how the idea for the book came from attempting to imagine all the things which could go wrong for an astronaut on Mars.
So that is exactly what I am going to do for Venus, going through the various accidents and problems that the astronaut Mark Watney faces in the Martian.
Mark Watney is abandoned on Mars amidst a Martian sandstorm which forces the crew to leave the planet. This is I believe the only major plot point in the book which Weir admits wasn’t realistic. Martian storms down blow with much force at all and could never threaten a Mars base.
I have not actually been able to find any definite answer to this, but what we do know is that Venus has very powerful vortexes at its poles and a thick atmosphere unlike Mars, which allows for some serious weather. At the cloud tops which would be most realistic for Venus colonization and exploration by astronauts, wind speeds can reach up to 355 km/h. If you go a bit below the cloud tops it can get up to 700 km/h.
Those numbers might not mean anything to you, so to get a sense of how strong those winds are, lets compare to storms on Earth. A thunderstorm on earth with wind speeds of 93 km/h is considered severe. Normally storms would start at 35 km/h. Strongest winds ever recorded on the earth was tropical cyclone, Olivia which reached 408 km/h.
In addition Venus has been proven to have lighting storms as powerful and frequent as those on earth, while this seems less common on Mars.
Venus also has major magnetic storms, both which could severely influence radio communications and electronics of any airship or spacecraft in the Venus atmosphere.
So it is more realistic that a storm could force Venus astronauts to have to leave and that it could cause significant damage to equipment. Assuming Venus cloud top colonization and exploration as I’ve described earlier, our Venus hero can’t be left in ditch, like Mark Watney.
Instead we could imagine he gets left behind in an airship or module which is blown away by strong winds, making the other astronauts lose contact as they board their Venus Ascent Vehicle (VAV), in non-geek-speak, the rocket which will take them into Venus orbit to rendezvous with an orbiting space ship which can take them back to earth.
Magnetic storms or lighting could knock out communications making it impossible for the others to contact the Venus equivalent of Mark Watney.
Mark Watney in the Martian doesn’t have enough food supplies to last until somebody can come back pick him up. His solution is to grow potatoes in Martian soil. Our Venus hero wont have that option, but would have to rely on a hydroponic solution instead, as described in my article on food production on Venus. As in the martian poop will have to be utilized for nutrition, except it will have to be processed, since it needs to be added to water rather than soil. The whole process will also be more complicated as our Venus hero will have to build a system of plastic tubes and water pumps. On the positive side, he will have four times as much sunlight to utilize.
Getting enough water could be solved in similar fashion as in the Martian by burning some form of rocket fuel. Alternatively he could utilize a large thin film to collect water through condensation from the Venus atmosphere.
Mark Watney has to travel quite far using a Martian Rover to locate a Mars rover as well as reaching the location of another Mars Ascent Vehicle (rocket) to take him off the planet.
This aspect is pretty hard to imagine exactly how would work out on Venus. Since everything has to happen at the cloud tops there are strong winds, nothing dropped in the Venus atmosphere will ever stay in a fixed location. It will just continuously get blown around the planet. A full circulation is done in about 50 hours on average.
I can imagine several possible scenarios for how successive Venus missions would rendezvous with modules left behind from previous missions.
- Satellites similar to GPS satellites are left in Venus orbit to keep track of locations of existing equipment or broadcast current position.
- Dropped modules attempt to maintain a pre-agreed upon fixed travel trajectory on Venus. They could maintain positions using a combination of star cameras, observing the sun, known features on the Venus surface using e.g. radar or lasers.
Our Venus hero would then have to calculate relative differences in position between himself and the VAV. With respect to getting there he we have more options than in the Martian.
- The habitat itself is like a large airship which could be moved to the destination. However doing so could potentially require more time or energy than he has available.
- Helicopters, quadcopter, airplanes or mini-Zeppelins are all possible choices for travel.
- The strong Venus winds blow in different directions depending on what layer you are in. So by simply changing altitude you can move in different directions. Hence you can potentially get to a desired location simply by using well timed altitude changes.
Hab Airlock Tearing
In the Martian the airlock gets blown out and the habitat loses pressure. On Venus there won’t be any pressure difference, so a blown airlock is unlikely.
However leaks or tears are possible, but they wont be as violent or abrupt. A tear in the balloon keeping the habitat floating could make it gradually drop down if not fixed. However this will be a slow process, as air will seep out rather than blow out.
Depending on the construction of the aerostat habitat, repairing a leak could require a difficult and dangerous extra vehicular activity, or could be a repair operation which could be performed inside the base.
Reaching too low altitudes before repair could cause various problems:
- Pressure increases, threatening the structural integrity of the habitat.
- Increase in sulfuric acid concentrations, which could corrode and damage exterior of habitat.
- Need for more lifting gas. A leak could cause loss of too much lifting gas, which can not be easily replenished. This could require some chemistry to figure out replacements. NH₃ normally used as fertilizer could be used as lifting gas. Hydrogen and Nitrogen would also work. Even Oxygen to some limited extent.
This is actually all I can remember by heart. There was quite a lot of details science problems Mark Watney had to solve. Many of the problems wont be relevant to Venus while there are other unique problems unique to Venus I could write about.
My strategy would be to look at what sorts of accidents have befallen airships in the past, anybody relying on oxygen tanks. People doing EVAs on Venus wont wear pressurized suits, and they will weigh the same as on earth, so the challenges will be much more similar to those of a smoke diver or diver. So we’ll have to look at common problems and accidents these people experience.