Buzz
A Mars mission comes with immense challenges, yet as this list demonstrates, none are beyond resolution. Decades of space exploration have proven that with ingenuity and relentless determination, our cosmic dreams can become reality.
10. The Cost Factor
The Apollo Moon Landing Program of the 1960s and ’70s cost the U.S. around $25 billion. The bulk of this spending occurred before Apollo 11, after which lunar landing challenges had been largely resolved, making later missions more affordable. A manned Mars mission, however, would demand significantly higher expenditures due to the vast cosmic distances involved—ranging from 36 million to over 250 million miles, given Mars’s highly eccentric orbit.
Beyond Earth's atmosphere, deep space is riddled with deadly threats, any of which could easily claim a human life. The Universe itself is a hostile environment, and sending a crew 250 million miles away demands meticulous preparation for every conceivable risk. Planning for each contingency comes at a steep cost, with even the most optimistic estimates starting at an improbable $1 billion. If the national and global economy continues its downturn, progress toward a manned Mars mission will remain frustratingly slow. Many of the challenges ahead are closely tied to this issue.
9. Earth-Borne Pathogens
Have you ever noticed that technicians and scientists handling spacecraft components wear sterile suits like surgeons? The reason is identical—to prevent contamination. Some microbes can endure the harsh conditions of space, with Deinococcus radiodurans ranking among the toughest. Unlike viruses, it is a bacterium capable of withstanding a staggering 5,000 grays of gamma radiation—while just 5 grays would be lethal to a human. The only reliable method to eliminate it is boiling, requiring 25 minutes, whereas botulinum succumbs in just 2 to 7 minutes.
Deinococcus is commonly found in spoiled food, sewage, and even household dust. But what if a Mars mission accidentally introduces it to the Red Planet? While we have yet to confirm the existence of Martian life, missions like Curiosity bring us closer to that answer every day. If microbial life exists on Mars, it has never encountered Earth-based organisms. While Deinococcus poses no direct threat to humans, it could spell catastrophe for any native extraterrestrial life forms.
Due to concerns like this, skeptics have raised ethical questions about setting foot on any planet that might host life. Any mission proposal must address these concerns before proceeding.
8. Propulsion Technology
So far, all human ventures into space have relied on rocket propulsion. To break free from Earth's gravity, a spacecraft must reach a staggering velocity of 11.2 km per second—about 25,000 mph. For comparison, the fastest bullets only travel around 3,132 mph. The only known way to launch an object beyond Earth's gravitational field is by placing it atop a controlled explosion—a massive bomb that we have learned to manage with precision.
The fuel needed to launch the Space Shuttle into orbit totaled 1,100,000 pounds for each of its two rocket boosters, primarily composed of ammonium perchlorate and aluminum. Despite the immense risks, catastrophic failures have been rare, with the Challenger disaster in 1986 standing as the most infamous. Yet beyond the dangers, most experts agree that chemical rocketry remains an incredibly inefficient method for transporting spacecraft beyond Earth's atmosphere.
In most science fiction stories, TV series, and films, spacecraft effortlessly leave Earth’s atmosphere using unexplained technology—likely because we have yet to fully grasp a propulsion method beyond rocketry. Nearly all vehicles, including airplanes, rely on internal combustion, which requires burning fuel. However, combustion is impossible without oxygen, which is why modern aircraft cannot exit our atmosphere—they simply stall and fall.
Scientists are actively researching alternative propulsion systems that do not depend on combustion. Many of these concepts explore anti-gravity technology. In the Star Wars films, spacecraft effortlessly lift off and soar into space—a capability that, if realized, would drastically simplify a Mars mission.
7. Psychological Strain in Space
Also known as 'cabin fever,' this phenomenon occurs when people are confined in small spaces for extended periods. Even a long road trip can cause tempers to flare—ask any highway patrol officer, and they’ll tell you that even Jesus and Gandhi would argue if stuck in a car long enough. Now imagine spending eight months crammed inside a spacecraft with limited activities. After a brief period of thrilling Martian exploration, the crew would face yet another eight months of isolation and monotony on the return journey.
See #3 for an effective strategy to counter what astronauts refer to as 'space dementia.' The primary method of prevention is keeping astronauts mentally engaged. One key reason why no violent crimes have occurred in space, regardless of nationality, is the relatively short duration of missions. The longest continuous stay in space was 437.7 days, achieved by Valeri Polyakov from 1994 to 1995. Though he spent 258 of those days physically alone, he remained in constant communication with Russian mission control and conducted 25 scientific experiments, ensuring his mind stayed occupied.
Polyakov’s extended mission aimed to demonstrate that maintaining psychological well-being throughout a Mars expedition is possible. Upon returning to Earth, he insisted on walking unaided to prove astronauts could do the same after a long-duration mission (see #5). However, psychological evaluations noted significant emotional strain—he appeared more withdrawn than usual and became easily frustrated by simple inquiries.
Now factor in the growing communication delay as the spacecraft journeys toward Mars. By the time it reaches Martian orbit, radio signals—traveling at the speed of light—will take up to 22 minutes for a roundtrip. Even at the closest approach, the delay would still be around 6.5 minutes. Such gaps render real-time conversations meaningless, eliminating the emotional connection that human interaction depends on. Meanwhile, crew members may tire of each other long before reaching Mars—only to then face the daunting prospect of the return trip. Space agencies rely on psychologists to select astronauts based on compatibility, but maintaining harmony for this long may be an unprecedented challenge.
6. The Spacesuit
The primary function of a spacesuit is pressurization. Without it, a human would inflate to about twice their normal size, resembling a powerlifter. While flash freezing and blood boiling would occur, neither is the primary cause of death. The real danger comes from the air-filled lungs, which would rupture like balloons. If you exhale fully rather than holding your breath, asphyxia would cause you to black out in about 15 seconds, leading to death within a minute—far before freezing or boiling becomes an issue. From Yuri Gagarin’s SK-1 to modern suits, most spacesuits have been designed to inflate and pressurize the body by expanding like balloons.
These suits have performed admirably so far, but astronauts have rarely spent extended periods in space. The suits are large, cumbersome, and restrict movement. On the Moon, astronauts adopted a loping gait—half-running, half-jumping—due to the weak gravity. Mars, with nearly two-fifths of Earth’s gravity, will allow a more Earth-like stride: astronauts will be able to bend their knees and walk forward, though they will float a few inches off the ground with each step. Recreating this gravitational effect on Earth is challenging; while water can simulate weightlessness to some extent, it also impedes movement.
For Martian exploration, a new type of spacesuit is required: a form-fitting suit, the opposite of the traditional inflated variety. Rather than pressurizing the suit, this new design would pressurize the body itself, enclosing the astronaut in a snug elastic shell that leaves only the head and throat exposed. This would result in a suit weighing just one or two pounds, compared to the 200-pound A7L worn by Neil Armstrong and Buzz Aldrin. The downside of this skintight design is the discomfort it causes, particularly around the groin area for men and the chest area for women, even with protective garments. Additionally, the suit must have built-in cooling to prevent heat exhaustion, which could strike within minutes in the absence of proper regulation.
5. Artificial Gravity
Zero gravity presents a significant challenge for long-term space missions. The human body is designed for Earth's gravity (1g), while other planets, like Jupiter, have a much stronger force (2.528g). In the weightlessness of space, astronauts face severe physical changes, most notably muscle atrophy and osteopenia (bone mass loss). To combat these effects, astronauts must work out vigorously for 4-5 hours a day, a task that can't be accomplished with free weights since they are weightless in space. Instead, spring-powered resistance, treadmills, and stationary bikes are used, but the results are still far from ideal for long-term health.
The concept of artificial gravity is most commonly demonstrated by centrifugal force. A spacecraft would need a giant spinning centrifuge, which creates adjustable force perpendicular to its axis, allowing astronauts to walk on the inner wall as if it were the floor. This idea is popular in science fiction, particularly in films like 2001: A Space Odyssey. Although no spacecraft currently features such a centrifuge (see #10), several designs are under active research.
Astronauts returning to Earth after just two months in orbit struggle to stand for more than five minutes, often needing assistance until their bodies readjust to Earth's gravity. The consequences for an astronaut who spends 8 months traveling to Mars would be even worse: they would lose about 1% of their bone mass every month. After the journey, they would face intense physical rehabilitation and scientific studies on a planet with only about two-fifths of Earth's gravity. Then, after all that, they’d have to make the return trip.
One possible way to simulate gravity is through magnetism, but magnetic boots would only keep the feet stuck to the surface without adding any significant weight to the body. As a result, muscle atrophy and osteopenia would continue almost unchanged.
4. Martian Pathogens
While #9 addresses “forward contamination,” this entry focuses on “reverse contamination.” If you're familiar with H.G. Wells's *The War of the Worlds*, you know that the Martians don't perish due to human military might, but rather by “the tiniest organisms that God, in his wisdom, put on this Earth.” If we reach Mars and return unscathed, we may find ourselves dealing with a backward version of Wells’s scenario.
Mars could very well be home to life, and if so, we must exercise extreme caution. The simplest life forms are often the deadliest. If Martian life is vulnerable to our pathogens, we, too, are defenseless against any Martian microbes. Having evolved without immunity to whatever life forms astronauts might bring back—on their spacesuits, spacecraft, or equipment, or even within their bodies—we could awaken organisms that have been in suspended animation for billions of years, now revived in their ideal environment.
A single Martian pathogen could trigger a global pandemic that wipes out all life on Earth. To mitigate this, Apollo 11, 12, and 14 astronauts who walked on the Moon were quarantined for 21 days until it was confirmed that the Moon had no life. However, the Moon lacks an atmosphere. Mars, on the other hand, has a thin one, with gases radically different from those of Earth. Therefore, the first astronauts to set foot on Mars will need to be quarantined for a considerable period after their return. But how can we eradicate any microbe they may bring back with them?
3. Unimpeded Cosmic Radiation
Our atmosphere and electromagnetic field are the sole reasons we’re not instantly incinerated. The Sun's ultraviolet radiation is mostly blocked by the atmosphere, while visible light, with its longer wavelengths, makes it through to the Earth's surface. However, this doesn't hold true once you're in outer space. Astronauts wear visors on their suits to protect against the Sun’s harmful rays—without them, direct sunlight would cause blisters and permanent blindness in mere seconds.
The aluminum Command Modules used in the Apollo Program easily blocked ultraviolet radiation. However, astronauts often reported brief flashes of bright blue or white light during their trips to and from the Moon. These flashes were not visible inside or outside the spacecraft, caused no pain, and didn’t interfere with the astronauts’ duties.
As more space missions encountered similar reports of these strange light flashes, scientists investigated and discovered that they were caused by 'cosmic rays.' Despite the name, cosmic rays are not actually rays, but rather subatomic particles, mainly individual protons, traveling close to the speed of light. These particles can penetrate spacecraft and create tiny holes in the material they pass through, though these holes are so small that they don’t allow for any leakage.
2. Meteoroids
Earth is hit by an estimated 1 septillion meteors, asteroids, and comets daily. Most of these are no bigger than a grain of sand, and even those as large as a van typically burn up before hitting the surface. The Moon, however, lacks an atmosphere to vaporize these objects, and despite its smaller surface area, you can easily spot the craters and debris scattered across it. Atmospheres act like incinerators, burning up much of the rock, metal, and ice, but in the vacuum of deep space, far from Earth, there’s no such protection for spacecraft or their crew.
Remember the scene in Star Wars IV when Han Solo warns Princess Leia about entering hyperspace without plotting a course, lest they fly straight into a meteor? That was one of the more scientifically accurate moments in science fiction.
What might an 8-month journey through deep space look like? Aside from the vast emptiness between Earth and Mars, there's a constant threat of debris, ranging in size, speeding through space at up to 50 times the velocity of the fastest bullet. One way to tackle this problem is to cover the spacecraft’s walls with heavy armor. But of course, that extra protection comes at the cost of added weight, making the already difficult task of breaking free from Earth’s gravity even harder.
1. The Spaceship
This entry ties closely with #10 and #5. While we already have a range of spacecraft that can reach Mars and carry out robotic tasks, adding human lives to the mix significantly increases the risks, as you might imagine. A spacecraft meant for an 8-month journey must be spacious enough to accommodate the crew’s mobility needs. It will also need to be designed with several factors from this list, including the next two considerations, in mind.
If the spacecraft is to feature a giant centrifuge for artificial gravity, it will not only need to be massive and costly but also incredibly complex in terms of engineering. Numerous NASA engineers and scientists have noted that we currently lack the technological advancements to build such a spacecraft. However, they remain optimistic, stating that we should have the necessary technology within the next few decades.
