Joel S. Levine: NASA plans to send humans on a scientific tour to Mars possibly as early as 2035. The journey will take approximately six to seven months (one way) and will cover up to 250 million miles (402 million kilometers) each way. The astronauts can spend up to 500 days on the Earth’s surface before returning to Earth.
NASA’s Artemis program plans to return humans to the moon this decade to train and prepare for a Mars mission as early as the 2030s. While NASA has several reasons for pursuing such an ambitious mission, the greatest is scientific exploration and discovery.
I am an atmospheric scientist and former NASA researcher involved in defining the scientific questions a Mars mission would investigate. There are many mysteries to explore on the red planet, including why Mars looks like it does today and whether life has ever existed there, in the past or present.
The geology of Mars
Mars is an intriguing planet from a geological and atmospheric perspective. It formed along with the rest of the solar system about 4.6 billion years ago. About 3.8 billion years ago, at the same time that life was forming on Earth, early Mars was very similar to Earth. It had an abundance of liquid water on its surface in the form of oceans, lakes and rivers and possessed a denser atmosphere.
Although the surface of Mars is completely devoid of liquid water today, scientists have found evidence of those lakes, rivers, and even an ocean coastline on its surface. The north and south poles are covered in frozen water, covered with a thin layer of frozen carbon dioxide. At the South Pole, the carbon dioxide veneer disappears during the summer, leaving the frozen water visible.
Today, Mars’ atmosphere is very thin and consists of about 95% carbon dioxide. It is filled with atmospheric dust from the surface, giving Mars’ atmosphere its characteristic reddish color.
Scientists know quite a bit about the planet’s surface thanks to sending robotic missions, but there are still many interesting geological features to investigate further. These features could tell researchers more about the formation of the solar system.
The northern and southern hemispheres of Mars look very different. About a third of Mars’ surface – mostly in the Northern Hemisphere – lies 2 to 4 miles (3.2 to 6.4 kilometers) lower, called the northern lowlands. The northern lowlands have some large craters, but are relatively smooth. The southern two-thirds of the planet, called the Southern Highlands, has many very old craters.
Mars also has the largest volcanoes that scientists have observed in the solar system. The surface is riddled with deep craters from asteroid and meteor impacts that occurred during Mars’ early history. Sending astronauts to study these features can help researchers understand how and when major events occurred during Mars’ early history.
Ask the right questions
NASA formed a panel called the Human Exploration of Mars Science Analysis Group to plan the future mission. I co-chaired the panel with NASA scientist James B. Garvin to develop and review key scientific questions about Mars. We wanted to find out which research questions required a human mission, instead of cheaper robot missions.
The panel came up with recommendations for several important scientific questions for human research on Mars.
One question is whether there is life on the planet today. Recall that life on Earth emerged about 3.8 billion years ago, when Earth and Mars were similar-looking planets that both had abundant liquid water and Mars had a denser atmosphere.
Another question is what kind of environmental changes have caused Mars to lose the widespread, abundant liquid water on its surface and part of its atmosphere.
These questions, along with other recommendations from the panel, are included in NASA’s architectural plan to send humans to Mars.
How do you get to Mars?
To send humans to Mars and return them safely to Earth, NASA has developed a new, very powerful launch vehicle, the Space Launch System, and a new human spacecraft called Orion.
To prepare and train astronauts for living on and exploring Mars, NASA has created a new program to return humans to the moon called the Artemis program.
In mythology, Artemis was the twin sister of Apollo. The Artemis astronauts will live and work on the moon for months to prepare for living and working on Mars.
The Space Launch System and Orion successfully launched on November 16, 2022, as part of the Artemis I mission. It made the Artemis program’s first unmanned flight to the moon, and once there, Orion orbited the moon for six days, reaching as high as 80 miles (129 kilometers) above the surface.
Artemis I returned to Earth on December 11, 2022, after its maiden voyage of 2.2 million kilometers.
Artemis III, the first mission to return humans to the lunar surface, is scheduled for 2026. The Artemis astronauts will land at the moon’s south pole, where scientists believe there may be large amounts of underground water in the form of ice that astronauts could mine, smelt, purify and drink.
The Artemis astronauts will set up habitats on the lunar surface and explore the lunar surface for several months.
Because the moon is only 386,000 km from Earth, it will act as a training ground for future human exploration of Mars. Although a Mars mission is still many years away, the Artemis program will help NASA develop the capabilities needed to explore the red planet.
Joel S. Levine, Research Professor, Department of Applied Sciences, William & Mary
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