New video shows tiny spacecraft ‘swarming’ Proxima Centauri

Earlier this year, NASA selected a very interesting proposal for Phase I development as part of the NASA Innovative Advanced Concepts (NIAC) program. Known as Swarming Proxima Centauri, it is a collaboration between Space Initiative and the Initiative for Interstellar Studies (i4is), led by Space Initiative Chief Scientist Marshall Eubanks.

The concept was recently selected for Phase I development as part of the NASA Innovative Advanced Concepts (NIAC) program this year.

Like other proposals involving gram-scale spacecraft and light sails, the “swarming” concept involves accelerating a small spacecraft equipped with a laser array to up to 20% of the speed of light. Last week, on the final day of the 2024 NASA Innovative Advanced Concepts (NIAC) Symposium, Eubanks and his colleagues presented an animation showing what this mission might look like.

The video and presentation give tantalizing clues about what scientists expect to find in the closest star system to our planet, which includes Proxima b, a rocky planet orbiting within the circumheliohabitable zone (CHZ) of its parent star.

As mentioned in a previous article, the concept of swarming Proxima Centauri has evolved significantly over the last few years. The concept first emerged in 2017 as a proposal for Project Lyra by i4is, which aimed to send small spacecraft to catch up with the interstellar object (ISO) Oumuamua.

But that has since evolved into a collaboration between i4is and Space Initiatives Inc., a Florida-based aerospace parts manufacturer that specializes in developing “femto spacecraft,” which are even smaller than nano spacecraft and measure in grams.

Just recently, Eubanks and his colleagues published a research paper tackling some of the big questions about interstellar exploration, including communication and what we can learn from a flyby of Proxima b.

At the 2024 NIAC Symposium, held September 10-12 in Pasadena, California, Eubanks and his colleagues had the opportunity to present their latest findings. As the video shows, the spacecraft swarm they envision would consist of 1,000 “pico spacecraft,” which they call “coracles” (small, rounded, lightweight ships), falling somewhere between nano and femto.

The probes are sturdy, armored on one side and covered with an optical ring (reflective material) on the other, about 2 centimeters (0.8 inches) thick, 4 meters (about 13 feet) in diameter, and weigh no more than a few grams each.

These would be accelerated by a roughly 100 gigawatt (GW) laser array that is expected to be available by the middle of this century, according to NIAC’s proposal. The spacecraft would also be equipped with lasers on its sides to facilitate communication with mission controllers on Earth.

As Eubanks said in his presentation, the animation actually features 1,000 probes, creating an artistically accurate depiction of the Proxima Centauri system. As the probes approach Proxima b, the red dwarf star stands out, while Alpha Centauri AB appears in the distant background. As the probes pass the planet, it also accurately depicts many of the celestial objects scientists hope to discover.

“This is in real time. This is pretty much what you would see if you predicted the redshift, blueshift, and redshift. And we had an artist draw this planet as a ‘eyeball planet,’ with a warm central area surrounded by cooler regions because we think this planet is probably rotationally locked.”

As Eubanks further explained, their collaboration has already produced two Coracle spacecraft prototypes, one of which was recently shown at the World Science Fiction Convention in Glasgow, and another one is currently on display in Pasadena.

Outlining the designs of the individual spacecraft, Eubanks emphasized the importance of consistency and how the configuration of the spacecraft fleet fosters communication and cohesion.

“Operational consistency is essential to the success of this mission. Operational consistency means that the whole spacecraft operates as one unit. Now, we realised that this doesn’t mean photon phase consistency – that’s not achievable. But if we have high enough accuracy clocks and laser distance measurements, we can determine where we are to within a few centimetres. We can determine whether the relative clocks are at roughly the same level, and (they) can function as one.”

“And the key part of that is, we can do that with a lot of things, like taking pictures of the planet. But the key part of it is what we call the light wall. The light wall is having all the probes send one coherent set of photons back to Earth, so that we can receive them collectively. We think we can send back a data rate of one kilobit per second. So we could send something like four gigabytes of data a year back to Earth. And that’s enough to get good data and really understand the system.”

Although the Swarming Proxima Centauri concept did not receive Phase II or III funding from NIAC this year, it remains a project worthy of study and further development. Like Breakthrough Starshot and other light sail proposals, this project shows what interstellar missions may look like in the coming decades. In that respect, ideas like this one show that we are at a point in history where exploration of our nearest star system is no longer a far-future idea that will require serious technological innovation first.