Why We Are Not Ready for Mars
There is a lot of buzz about going to Mars, but in truth we are very far from sending humans. We need a dose of reality before we get too carried away with this fantasy.
Our success rate for sending robotic probes to Mars is about 50%. A human expedition to Mars will be vastly more complicated and dangerous.
The fact is that we do not even have a design for a Mars mission. In the near future we could possibly send a crew to do a fly-by of Mars with no landing. This would involve enormous risks and costs. Even such a limited mission would require a minimum of 18 months in space.
What we cannot do is to land a crew on Mars. And even if we could, we have no way of getting the crew off of Mars and returning it to Earth.
The Mars base will need to sustain the crew for up to two years on the surface. This would require a very large and complicated setup. We will need advanced life support systems including radiation shielding, oxygen production, air recycling, water extraction and/or recycling, and electrical generation. We will also need space suits and vehicles for exploration, and laboratory space and equipment for research. And finally we will need maintenance and repair systems and spare parts to keep it all running. We will also need a medical facility. Eventually we will want to grow our own food as well.
I would envision the proposed Mars base would be as large and complex as the International Space Station. While the existence of the ISS proves that we can build such a structure, the problem comes when we try to land it on Mars. Even if the Mars base is to be built in modules, as was the ISS, there is still a lot of weight to land on the surface. As the Mars atmosphere is less than 1% as dense as Earth’s parachutes are of extremely limited use. It has been a struggle even to land small, robotic crafts on the surface. But a human mission to Mars will require modules that are much larger and heavier than anything we have sent thus far. The only way we know to accomplish such landings is to use descent engines requiring massive amounts of rocket fuel. This fuel would be very heavy and would need to be sent from Earth.
Lifting off from Mars creates its own problems. We might assume that there will be an ascent ship carrying the astronauts to an Earth return vehicle parked in Mars orbit. But the details of this part of the mission have yet to be worked out. Here again there is a fuel issue. Where is the fuel for the ascent vehicle and the Earth return vehicle going to come from? Either we need to haul it from Earth, or else we need to manufacture it on Mars. A fueling station on Mars would add even more to the cost, complexity, and weight of the Mars base. The fueling station would extract water from the Martian environment, split it into oxygen and hydrogen gasses using electricity, and then both gasses would be loaded into the fuel tanks of the rockets. The same fuel might also be used to power the rovers on the surface as an alternative to solar power.
There is no way to cost out a human expedition to Mars at this point. The mission design is still unknown. Preliminary estimates from NASA have suggested a cost of $500 Billion (one-half trillion) for one crewed mission. It would be safe to assume that we could send a thousand robotic missions to Mars for far less than the cost of one crewed mission. And, when it comes right down to it, there is very little that a crewed mission could accomplish that could not be done with robotic missions except for the flag planting photo opportunity.
We live in a time when cruise missiles have largely replaced manned bombers, and drones are replacing fighter jets. When we remove the human factor from the cockpit we greatly improve the aircraft and its performance. A cruise missile or drone has no need for life support, windows, or complicated safety equipment such as ejection seats, fire extinguishers, or life rafts. A drone is far more maneuverable than a fighter jet and can perform high-speed turns at g-forces that would kill a human pilot. Removing the human element, and the requisite life support and safety gear, creates a vehicle with a greatly reduced size and weight, and a higher power-to-weight ratio. In the same way that a motorcycle can out maneuver and outperform a car, a drone can out maneuver and outperform a piloted aircraft. And most importantly, a drone can be flown from a control room in Oklahoma instead of risking a pilot’s life in a combat zone.
Our robotic technology is increasing geometrically. Soon self-driving cars will become commonplace. So why not self-driving rovers on Mars?
Almost all of our actual science in space has been done by robotic means, from the Voyager spacecraft to the Hubbell Space Telescope to the New Horizons mission to Pluto. The Mars orbiters and rovers have yielded some great science and continue to do so even after years of activity.
And then there are the human factors to consider in a crewed mission to Mars. Just the trip out and back will be difficult for the crew. Imagine sharing a recreational vehicle with three to five other people, except in this case the trip will last about three years and all of the doors and windows will be welded shut. There will be no chance of getting away from the constant pressures and tensions that might be created from such close contact. And what happens if there are problems back home such as a seriously ill child or the loss of a loved one?
The human body is not meant for life in outer space. Extended periods of zero gravity cause a breakdown of bone and muscle mass. Even extensive exercise requiring hours each day do not fully compensate for this deterioration. Imaging an astronaut stepping onto the surface of Mars and breaking her leg due to atrophy caused by months of zero gravity.
The astronauts on the Mars mission will also be subjected to all of the diseases and conditions that affect all humans. Additionally there can and will be accidents. What can be done about appendicitis, breast cancer, heart attacks, burns, puncture wounds, and all of the other situations requiring emergency medical care when an astronaut is in deep space and several years from Earth?
Away from the Earth and its protective atmosphere and radiation belts, astronauts could be fried by radiation caused by a solar flare or a coronal mass ejection. Even cosmic background radiation could impair the crew and its mission. Micro meteors could puncture the hull or damage essential equipment.
One thing is certain. Beyond near-Earth orbit, any form of rescue is out of the question. Apollo XIII managed to limp back from a catastrophic explosion on the way the moon. But Apollo XIII was only a few days from Earth.
Three things from the world of science fiction are needed right now before we can be truly prepared for long duration space missions:
- Advanced propulsion systems that can get us to Mars and back in weeks instead of years.
- Shields or force fields to protect us from radiation and impacts with space debris.
- Artificial gravity to prevent muscle and bone loss.
With these technologies in place a crewed mission to Mars begins to look like a possibility.