Can robots really replace human astronauts?

An autonomous spacecraft flew past the sun just before Christmas, coming closer than any man-made object before. NASA's Parker Solar Probe swoops through the atmosphere on a mission to discover more about the sun, including how it affects space weather here on Earth.

It was a landmark moment for humanity, but one without any direct human involvement, as the spacecraft carried out its pre-programmed mission on its own as it flew past the sun, with absolutely no contact with Earth.

Over the past six years, robotic probes have traveled across the solar system to destinations beyond the reach of humans. During the 10-day flybythe Parker Solar Probe experienced temperatures of 1,000 degrees Celsius.

But the success of these autonomous spacecraft, coupled with the rise of new advanced artificial intelligence, raises questions about what role humans might play in future space exploration.

Some scientists question the need for human astronauts.

“Robotics are advancing rapidly and the case for sending humans is getting weaker and weaker,” said Lord Martin Rees, Astronomer Royal. “I don't think any taxpayer money should be used to send humans into space.”

He also noted the risks to humans.

“The only reason to send humans there is as an adventure, an experience for rich people, and this should be privately funded,” he argued.

Physicist Andrew Coates of University College London agrees. “For serious space exploration, I prefer robotics,” he said. “(They) went further and did more.”

They're also cheaper than humans, he believes. “As artificial intelligence advances, robots will become smarter and smarter.”

But what does this mean for future generations of budding astronauts? Sure, humans can perform certain functions in space, but robots, no matter how advanced, will never be able to?

Robotic spacecraft have visited every planet in the solar system, as well as many asteroids and comets, but humans have only visited two destinations: Earth orbit and the moon.

In total, about 700 people have been to space since 1961, when then-Soviet Yuri Gagarin became the first space explorer. Most of these are already in orbit (circling the Earth) or suborbital (short vertical jumps into space that last several minutes on vehicles such as Blue Origin's New Shepard rocket).

“Prestige will always be a reason why we put people in space,” said Dr. Kelly Weinersmith, a biologist at Rice University in Texas and co-author of “Cities on Mars.” “It seems like has been considered a good way to show that your political system works and your people are talented.”

But beyond an innate desire for exploration or prestige, humans also conduct research and experiments in Earth orbit (such as the International Space Station) and use these to advance science.

Robots can contribute to scientific research, with the ability to travel to places inhospitable to humans, where they can use instruments to study and probe the atmosphere and surfaces.

“Humans are more versatile than robots and we can do things faster than robots, but it's really difficult and expensive for us to survive in space,” Dr Weinersmith said.

Author Samantha Harvey expresses this more lyrically in her 2024 Booker Prize-winning novel Orbital: “A robot doesn’t want water, nourishment, excretion, sleep… it wants nothing. Want it and don’t ask for it.”

But there are also disadvantages. Many robots move slowly and methodically—on Mars, for example, rovers (remotely controlled motor vehicles) travel at just 0.1 mph.

“AI can beat humans at chess, but does that mean they can beat humans in an exploration environment?” asked Dr. Ian Crawford, a planetary scientist at the University of London. “I just don't think we know.”

However, he does believe that AI algorithms could potentially make the rover “more efficient.”

Technology can play a role in supplementing human space travel by freeing astronauts from certain tasks, allowing them to focus on more important research.

“(AI can be used to) automate tedious tasks,” explained Dr. Kiri Wagstaff, an American computer and planetary scientist who previously worked at NASA's Jet Propulsion Laboratory in California. “On a planetary surface, humans get tired and lose focus, but machines don't.”

The challenge is that operating systems such as Large Language Models (LLMs), which process large amounts of text data to understand and generate human language, require a lot of computing power. “We are not yet at the stage where we can run an LL.M. on a Mars rover,” Dr Wagstaff said.

“The rover's processors run at about one-tenth the speed of a smartphone” – meaning they can't handle the intense demands of running an LL.M.

Complex humanoid machines with robotic arms and limbs are another form of technology that could undertake basic tasks and functions in space, especially as they more closely mimic human physical capabilities.

NASA's Valkyrie robot was built at Johnson Space Center for use in the 2013 Robotics Challenge. Weighing 300 pounds and standing 6 feet 2 inches tall, it looks not unlike a Star Wars stormtrooper, but it's one of a growing number of humanoid machines with superhuman abilities.

Long before Valkyrie was born, NASA Robot astronaut It is the first humanoid robot designed for use in space, capable of undertaking tasks originally performed by humans.

Its specially designed hands mean it can use the same tools as astronauts and perform complex, delicate tasks, such as grabbing objects or flicking switches, that would be too challenging for other robotic systems.

The latest model of Robonaut flew aboard the space shuttle Discovery in 2011 to the International Space Station, where it helped with maintenance and assembly.

“If we need to replace a component or clean a solar panel, we can do it with a robot,” said Dr. Sean Azimi, leader of the Dexterous Robotics Team at NASA's Johnson Space Center in Texas. “We see robots as a way to protect these habitats when humans are no longer around.”

He thinks robots could be useful, not to replace human explorers but to work alongside them.

Some robots are already working on other planets without humans, sometimes even making decisions on their own. For example, NASA's Curiosity Mars rover explore A region on Mars called Gale Crater allows some scientific research to be conducted autonomously without human input.

“You can direct the rover to take pictures of a scene, look for rocks that might meet the mission's scientific priorities, and then automatically fire a laser at that target,” Dr Wagstaff said.

“It can take readings from specific rocks and send them back to Earth while humans are still sleeping.”

But the capabilities of rovers like Curiosity are limited by their slow speeds. There are also things they can't compete with. That said, humans have the added benefit of motivating people to return to Earth in a way that machines cannot.

“Inspiration is an intangible thing,” Professor Coates said.

Retired NASA astronaut Leroy Chiao, who flew three space flights aboard NASA's space shuttles in the 1990s and 2000s and traveled to the International Space Station, agrees. “When people are doing something, people connect.

“The public is excited about robotic missions. But I expect the first human on Mars to be bigger than the first moon landing.”

Humans have not left Earth orbit since the last Apollo mission visited the moon in December 1972. NASA hopes to bring humans back there within a decade through its Artemis program.

this The next manned mission Four astronauts will orbit the moon in 2026. Another mission planned for 2027 will land NASA astronauts on the lunar surface.

At the same time, the China Space Administration also hopes to send astronauts to the moon.

On the other hand, Elon Musk, CEO of the American company SpaceX, also has his own space-related plans. He has said his long-term plan is to establish a colony on Mars where humans can land.

His idea is to use Starship, a massive new vehicle his company is developing, to transport up to 100 people at a time, with the goal of There will be 1 million people on Mars in 20 years.

“Musk believes we need to move to Mars because Mars can be a fallback base for humans if a disaster occurs on Earth,” Dr. Weinersmith explained. “If you believe this argument, then sending humans into space is necessary. “

However, there are still many unknowns about life on Mars, including countless technological challenges that she said have yet to be solved.

“Maybe babies can't develop in that environment,” she said. “There are ethical questions (like this) that we don’t have answers to.

“I think we should slow down.”

Lord Rees has his own vision, though, in which human and robotic exploration might merge, making humans themselves cyborgs to cope with extreme environments. “I can imagine they're going to use genetic modifications, robotic add-ons, all that stuff to deal with very harsh environments,” he said.

“We might have a new species that would be happy to live on Mars.”

Until then, however, humanity will likely continue to take small steps into the cosmos, following the path long trodden by robotic explorers before it.

Top image credit: NASA

BBC in-depth report is the new home of websites and apps delivering the best analysis and expertise from our top journalists. Under a unique new brand, we'll bring you fresh perspectives that challenge assumptions and in-depth coverage of the biggest issues to help you make sense of a complex world. We'll also be showcasing thought-provoking content from BBC Sounds and iPlayer. We start small but think big, and we want to know what you think – you can send us your feedback by clicking the button below.