Swarming Proxima Centauri: Coherent pico spacecraft swarms across interstellar distances – Astrobiology

Swarming Proxima Centauri: Coherent Picospacecraft Swarms Over Interstellar Distances
Swarming Proxima Centauri: Coherent picospacecraft swarming across interstellar distances

Graphical representation of the swarming Proxima Centauri: coherent picospacecraft swarming across interstellar distances Thomas Eubanks

Small gram-scale interstellar probes powered by laser light will likely be the only technology that can reach a new star this century. We imagine that by mid-century there will be available a laser beamer powerful enough (~100 GW) to boost a few grams to a relativistic speed, laser sails robust enough to survive launch, and terrestrial light buckets (~ 1 square kilometer) that are large enough to survive the launch. capture our optical signals. Next, our proposed representative mission, around the third quarter of this century, is to fly past our nearest neighbor, the potentially habitable world Proxima b, with a large autonomous swarm of thousands of small probes.

Given the extreme constraints on launch mass (grams), onboard power (milliwatts), and communications aperture (centimeters to meters), our team has determined in our work over the past three years that only a large swarm of many probes working in harmony produce an optical signal strong enough to travel the immense distance back to Earth. The eight-year delay during the round trip eliminates any practical control by Earth. Therefore, for example, the swarm must have an extraordinary degree of autonomy to determine what data is sent back to Earth. The reader will thus see that coordinating the swarm of individuals into an effective whole is the dominant challenge for our representative mission to Proxima Centauri b. The coordination, in turn, relies on establishing a mesh network over low-power optical links and synchronizing onboard probes’ clocks with Earth and each other to support precise position-navigation (PNT) timing.

Our representative mission begins with a long series of probes launched one by one down to ~0.2c. After launch, the drive laser is used for signaling and clock synchronization, providing a continuous time signal like a metronome. The initial boost is modulated so that the tail of the string catches up with the head (“time on target”). By taking advantage of the drag of the interstellar medium (“velocity on target”) during the 20-year cruise, the group stays together once assembled. An initial sequence 100 to 1000 s AU long dynamically coalesces over time into a lens-shaped mesh network #100,000 km wide, sufficient to account for ephemeris errors at Proxima, allowing at least some probes close to pass the target.

A swarm whose members are in known spatial positions relative to each other, with state-of-the-art micro-miniaturized clocks to stay in sync, can use the entire population to communicate with Earth, periodically building up a single short but extremely bright simultaneous laser pulse. of them all. Operational coherence means that each probe transmits the same data, but adjusts its emission time according to its relative position, so that all pulses arrive simultaneously at the receiving arrays on Earth. This effectively multiplies the power of each probe by the number N probes in the swarm, yielding an order of magnitude greater data yield.

A swarm would tolerate significant attrition along the way, reducing the risk of “putting all your eggs in one basket” and closely observing Proxima b from multiple vantage points. Fortunately, we don’t have to wait until mid-century to make practical progress; we can now explore and test swarming techniques in a simulated environment, which we propose in this work. We expect that our innovations will have a profound effect on space exploration, complementing existing techniques and enabling entirely new types of missions, for example pico spacecraft swarms covering the entire cislunar space, or instrumenting an entire planetary magnetosphere. Well before mid-century, we anticipate a number of such missions, starting in Earth or lunar orbit but over time extending deep into the outer solar system. Such a swarm could, for example, explore the rapidly receding interstellar object 1I/’Oumuamua or the Sun’s gravitational lens. These would both be the precursors to the ultimate interstellar mission, but would also be scientifically valuable in their own right.

—Thomas Eubanks Space Initiatives, Inc.:

2024 NIAC Phase I Selection, NASA

Astrobiology, Interstellar,

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