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We need to consider the benefits of sending life out of the solar system, say researchers

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University of California, Santa Barbara professors Philip Lubin and Joel Rothman and their colleagues plan to launch small cryptobiotic life forms into interstellar space.

Our ability to explore the cosmos by direct contact has been limited to a small number of lunar and interplanetary missions. However, NASA’s Starlight program points to a way forward to send small, relativistic spacecraft away from our solar system via remote directed energy propulsion. These miniaturized spacecraft are capable of robotic exploration but can also transport seeds and organisms, marking a profound shift in our ability to both characterize and extend the known range of life. Lantin et al. explore the biological and technological challenges of interstellar space biology, focusing on radiation tolerant microorganisms capable of cryptobiosis. Image credit: University of California, Santa Barbara.

“I think it’s our fate to keep exploring,” said Professor Rothman, a researcher in the Department of Molecular, Cellular, and Developmental Biology at the University of California, Santa Barbara.

“Look at the history of the human species. We are exploring on smaller and smaller levels down to subatomic levels and we are also exploring on larger and larger scales. “

“Such a relentless drive for exploration is at the heart of who we are as a species. “

The biggest challenge of interstellar travel on a human scale is the enormous distance between Earth and the nearest stars.

NASA’s Voyager missions have proven that we can send objects the 19.3 billion km (12 billion miles) needed to break out of the bubble surrounding our solar system, the heliosphere.

But car-sized probes, traveling at speeds of over 56,000 km / h (35,000 mph), have taken 40 years to achieve and their distance from Earth is only a tiny fraction. of that of the next star. If they were heading for the nearest star, it would take them over 80,000 years to reach it.

This challenge is a major focus of the team’s work, in which they reinvent the technology it would take to reach the next solar system in human terms.

Traditional on-board chemical propulsion is out; it cannot provide enough energy to move the craft fast enough, and its weight and the current systems needed to propel the ship are not viable for the relativistic speeds the craft must achieve.

New propulsion technologies are needed – and that’s where the energy research program led by the University of California, Santa Barbara, which uses light as a “propellant” comes in.

“This has never been done before, to push macroscopic objects at speeds approaching the speed of light,” said Professor Lubin, a researcher in the physics department at the University of California at Santa Barbara.

“The mass is such a huge barrier, in fact, that it precludes any human mission for the foreseeable future.”

As a result, the team turned to robots and photonics. Small probes with on-board instrumentation that detect, collect and transmit data to Earth will be propelled at up to 20-30% of the speed of light by the light itself using a laser array stationed on Earth, or maybe on the Moon.

“We don’t leave the house with it. The main propulsion system stays “at home” while spacecraft are “fired” at relativistic speeds, “said Prof Lubin.

“The main propelling laser is on for a short time, then the next probe is ready to be fired. “

As the program evolves, the spacecraft gets bigger with improved capacity.

The core technology can also be used in a modified mode to propel much larger spacecraft through our solar system at slower speeds, potentially allowing human missions to Mars in just a month, including shutdown. It is another way of spreading life, but in our solar system.

At these relativistic speeds – around 161 million km / h (100 million mph) – the wafercraft would reach the next solar system, Proxima Centauri, in about 20 years.

Achieving this level of technology will require continuous innovation and improvement in both space wafer and photonics.

The basic project to develop a roadmap for achieving relativistic flight via directed energy propulsion is supported by NASA and private foundations such as the Starlight program and by Breakthrough Initiatives such as the Starshot program.

“When I learned that the mass of these contraptions could reach levels of grams or more, it became clear that they could accommodate live animals,” Professor Rothman said.

“We realized that Caenorhabditis elegans could be the first Earthlings to travel between the stars. These intensively studied roundworms may be small and simple, but they are experimentally accomplished creatures. “

“Research on this small animal has so far led to Nobel prizes for six researchers.”

Caenorhabditis elegans are already space travel veterans, being the subject of experiments conducted on the International Space Station and aboard the Space Shuttle, even surviving the tragic disintegration of the Columbia Shuttle.

Among their special powers, which they share with other potential interstellar travelers the authors are studying, tardigrades can be placed in suspended animation in which virtually all metabolic functions are shut down.

Thousands of these tiny creatures could be placed on a wafer, animated suspended, and stolen in this state until they reach their desired destination.

They could then be awakened in their tiny StarChip and precisely monitored for any detectable effect of interstellar travel on their biology, with the observations being relayed back to Earth via photon communication.

“We can ask them how well they remember trained behavior as they move away from their earthly origin at near light speed, and examine their metabolism, physiology, neurological function, reproduction and aging, ”said Professor Rothman.

“Most of the experiments that can be done on these animals in a lab can be done on board the StarChips as they travel through the cosmos.”

“The effects of these long odysseys on animal biology could allow scientists to extrapolate to the potential effects on humans.”

“We could start to think about designing any interstellar transporters, whatever they are, in a way that could improve the problems detected in these small animals.”

The teams paper was published in the journal Acta Astronautica.

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Stephane Lantin et al. 2022. Interstellar space biology via Project Starlight. Acta Astronautica 190: 261-272; doi: 10.1016 / j.actaastro.2021.10.009