NASA studies an interstellar mission for 2069

Voyager-1 is the ship that has farthest reached space. It took off in 1977 and took 37 years to leave the Solar System. At its current dizzying speed - 17 kilometers per second - it will take another 70,000 years to reach the nearest star. If humans are so hard to agree on a plan to mitigate climate change 100 years from now, how to think of a mission to reach another star and its planets in a reasonable time?

This is what Anthony Freeman of the Jet Propulsion Laboratory, the epicenter of NASA's robotic missions (JPL), has done. Along with Leon Alkalai, head of the strategic planning office, the engineer has just presented the first concept for an interstellar mission that would be launched in 2069, when 100 years of the arrival of man on the moon is fulfilled.

"NASA began contemplating interstellar missions 30 years ago," Freeman explains on the phone from his office. "So the focus was on how to make communication between the ship and the Earth possible. Then we have reviewed these ideas more or less every decade, "he explains.
The new project - even without a name - "is at a very early stage as a mission concept", warns Freeman, but coincides with the recent start of similar projects promoted by private organizations and with the approval in the US Congress of a document promoted by the Republican John Culberson that expressly asks NASA to start financing this project already.

The destination of the future mission would be Próxima Centauri, where a habitable planet the size of the Earth has been discovered. Freeman's proposal includes a ship capable of traveling at 10% of the speed of light, which would reach Proxima in 40 years. The first images taken from there would reach Earth some four years later, in 2113, almost a century from now. This means that the engineers and scientists who analyzed those images would not even have been born when the ship was launched, and probably most of its original designers would be dead by then. No space mission has faced such horizons and this is one of its biggest challenges, admits Freeman. "Now the space missions are done with a very conservative approach. If we really want to send a mission to another star we can not do that, we have to be a little more crazy, "he acknowledges.
When the ship reaches its destination, the technology of the moment will have surpassed it completely. The Freeman concept explores a probe capable of being updated, reprogrammed and transformed without the need to send all the instructions from the ground, for example using 3D printers and artificial intelligence systems capable of creating new software programs. The concept developed by Freeman and Alkalai also suggests a support mission, whose objective would be to travel 550 astronomical units (each equivalent to the distance between Earth and the Sun) in the opposite direction to Proxima Centauri. His objective was to take images taking advantage of the phenomenon of gravitational lenses, which uses the gravity of celestial bodies like the Sun as if it were a magnifying glass to enlarge the image of the star that we wish to observe.

The long-term approach would allow the complex technologies to be developed gradually and tested with closer and more affordable targets, such as the Oort cloud or Planet X, says Freeman, who presented his concept a few weeks ago during the Union Congress. Geophysics of the United States
For now there are no new forms of propulsion for an interstellar trip. Neither the chemical fuel of the rockets, nor the solar panels, nor the nuclear energy serve to cover the distances of more than 40 billion kilometers to the nearest stars in an affordable time. Some alternative ideas are nuclear fusion or explosions of matter and antimatter, which have not yet been developed.

Another option is the "directed energy" proposed by Phillip Lubin, a physicist at the University of California at Santa Barbara (USA). The system is based on ships with solar sails powered by laser light emitted from Earth or space. The smaller the probe, the faster it can be, up to a limit that can reach 20% of the speed of light, says Lubin. In this case, the necessary technology does exist already and the physicist expects it to experience an exponential development similar to electronics. Since 2015, the Deep-In project has received two rounds of funding from NASA for a total of more than half a million euros. "With an adequate budget, the technology we are developing may be ready for an interstellar mission before the 100th anniversary of the Apollo landing [11]," says Lubin.
The same year that the planet was discovered in Proxima, Stephen Hawking sponsored the new project to search for life with a swarm of tiny laser-powered spacecraft capable of reaching that star in 20 years. Behind the initiative was Yuri Milner, a Russian billionaire who has become one of the greatest patrons of world science and who put 100 million dollars in the project. The propulsion system of these ships, which made their first trip to space in 2017, is based on Lubin's. "We are excited that NASA has started working on interstellar missions," says Pete Worden, former director of the Ames Center at the US space agency and current executive director of Breakthrough Starshot, Milner's project. The organization is negotiating with NASA to cooperate in several fields, including interstellar travel, and they hope to announce the details in a few months, he says.

Other experts working in current and future missions doubt that these projects are viable. Mar Vaquero, flight engineer at JPL, believes that the proposal of her colleagues is too "crazy and theoretical", although she adds that "there is no doubt that such a concept invites reflection". In addition, there is no shortage of parallels with recent successful missions. "The Cassini primary route was not fully planned at the time of launch, it was during the cruise phase when it was designed, something similar can happen with this concept, and we will meet with challenges in different fields, such as propulsion, navigation, or the same protection of the ship and its systems during so many years of interstellar travel, but I have no doubt that we can solve them, "he says.