Earth may be our beloved home planet, but Mars exudes the main character’s energy.
Earthlings have long aspired to travel to the Red Planet and check whether it harbors any form of life. In July 1976, we used a robot to start searching: the Viking 1 spacecraft landed that month, followed by Viking 2 in September. The Viking twins began sending back photos and data from experiments designed to search for life on Mars. One of the first lessons learned is that it is difficult to conduct scientific experiments at a distance of 23 million kilometers.
On the occasion of the 50th anniversary of this historic landing, a look back at the failures and successes of the exploration of Mars from Viking. Lisa Grossman, senior astronomy editor, reports the discoveries and setbacks that guided the hunt for Martian lifeincluding NASA’s revised approach of looking for habitable conditions before directly looking for evidence of life. As Grossman writes, the wealth of information we now have about the Red Planet has renewed scientists’ enthusiasm for finishing what Viking started.
The next step would be to bring samples to Earth for further study. “The technology is there or very close,” Grossman told me. “NASA has been landing things on Mars for a very long time and has become very good at it.” The Perseverance rover, for example, has been collecting rock samples since 2021 and caching them to return to Earth.
But Congress cut funding for the Mars Sample Return mission in 2024, leaving the project stalled. Most of NASA’s efforts are instead directed toward the Trump administration’s focus on returning humans to the Moon. But Grossman notes that continued study of Mars is essential to discovering whether there really is, or ever was, life there — and also to knowing what it would take to one day visit this intriguing red neighbor in person.
In this issue we also explore life in the extreme environment of Earth’s stratosphere. The big news: Not only do the microbes live 30 kilometers above sea level, but they shuttle between the surface and the sky and contain common plant pathogens. Life on Mars, if it exists, could end up being a lot more familiar than expected.
