Humans have sent more spacecraft to Mars than any other world beyond Earth. Today, there are 8 missions operating on or around the planet, with 3 more due to arrive in 2021 to kick off the next generation of exploration.
The United States and Soviet Union began sending robotic probes to Mars in the 1960s. Many of those early attempts failed, until NASA’s Mariner 4 spacecraft successfully flew by Mars in 1965, revealing a barren landscape. Later missions saw Earth-like deltas and canyons suggesting that liquid water had shaped the surface.
The NASA Viking landers of the mid-1970s—the first to land on Mars successfully—tested the Martian soil to look for possible signs of life. The results showed no clear evidence for the presence of living microorganisms in soil near the landing sites.
To determine whether or not life once existed on Mars, NASA initiated the Mars Exploration Programme in the mid-1990s to systematically explore the Red Planet. In 2000, the programme adopted a goal to “follow the water.” Because liquid water is essential to life on Earth, the search for life elsewhere starts by looking in places where this key ingredient exists or used to exist.
Orbital missions to Mars study the planet’s atmosphere, map and identify major geologic features, and determine the composition of minerals and ice. Orbital missions are easier than landing on the surface, and more affordable. Orbital spacecraft can also serve as critical relay satellites for surface spacecraft and future human missions. Besides Earth, Mars is the only planet in the solar system with a global satellite communications system.
Although much can be learned about Mars from orbit, we must land on the surface. Initially, this involved stationary landers that could analyse one location. But on Earth, geologists travel widely to study the composition of different types of rock in order to reconstruct a complete picture of the planet’s past. To do this on Mars, NASA developed a series of spacecraft with wheels called rovers: Sojourner, Spirit, Opportunity, and Curiosity. Rovers have proved to be a highly efficient way to explore the surface, and of the 3 missions launched to Mars in 2020, 2 include a rover.
The Emirates Mars Mission (EMM) is the United Arab Emirates’ first mission to Mars. EMM is designed to orbit Mars and study the dynamics in the Martian atmosphere on a global scale, and on both diurnal and seasonal timescales.
The next step in Mars exploration is returning samples from the surface back to Earth. Bringing just a few small samples back to Earth will allow us to dramatically advance our understanding of Mars—including whether it may have supported life. NASA’s Perseverance rover will collect soil and rock samples and store them in small tubes for future return to Earth, but the missions that will return those samples still need to be formally approved and funded.
Sending scientists directly to Mars remains the ultimate goal for Mars exploration. A human in a spacesuit would be able to move, collect samples much more quickly than a robot being controlled from Earth, where the average round-trip time to send and receive rover signals is 25 minutes.
The National Academies of Sciences, Engineering, and Medicine laid the groundwork for planetary protection policies that balance responsibility with the desire to explore. The Planetary Society advocates for these recommendations and supports
scientifically-motivated guidelines for responsible planetary protection.
Source: The Planetary Society