Should We Send Humans to Mars?

Fifty years ago this month, humans last set foot on the moon. Now the United States and other countries are gearing up to send people back again. This time, however, the moon is a stepping stone toward a bigger goal: putting humans on Mars.

Why Mars? As one of our closest planetary neighbors, Mars is within reach. Also, its surface seems to have once been similar to Earth’s, so scientists want to learn more about how Mars evolved—and whether life once existed there.

NASA, the U.S. space agency, has teamed up with the Canadian, European, and Japanese space agencies to get humans to the moon by 2025. As part of the Artemis program, they plan to set up a lunar base camp, putting people one step closer to Mars. Meanwhile, private companies are developing technology for Mars missions. The hope is to land humans on Mars in the 2030s.

People who favor sending humans to the Red Planet say astronauts would be able to explore and analyze samples more efficiently than rovers and other remote devices.

Other people, however, say putting humans on Mars is not worth the health risks that astronauts would face traveling to and exploring that planet. They say we should focus on other space destinations instead.

Should we send humans to Mars? Two space scientists weigh in.

It is important to explore Mars, and humans play a valuable role in that research. Though robotic devices can do a lot, they lack the critical firsthand experience only humans can capture. But sending people to Mars for long periods would be extremely unsafe, and we shouldn’t do it.

For one thing, space radiation is very dangerous for humans. One kind, galactic cosmic rays (GCRs), consists of high-energy particles that come into our solar system from faraway exploding stars. GCRs can cause cancer and even brain damage. Earth’s thick atmosphere protects us from them. But the longer astronauts are in space, traveling to Mars and spending time on its surface, the more they’d be exposed to those rays and the more harm they’d experience.

Luckily, there’s a safer destination: Titan, one of Saturn’s moons. It has a thick atmosphere that provides protection from dangerous radiation.

Although Titan is much farther from us than Mars, it has many Earth-like qualities that could help us learn more about our home planet. For instance, Titan has lakes and seas. It also has wind, weather, and seasons similar to Earth’s, and many resources we could use to build a self-sustaining settlement.

Though human exploration of Titan is likely to be far in the future, the idea of it could inspire upcoming generations of scientists and engineers to reach for distant locations in our solar system and beyond—and help us better understand Earth.

—Amanda R. Hendrix
Senior Scientist, Planetary Science Institute