Philip Lubin writes:
“There has been a game change in directed energy technology whose consequences are profound for many applications including photon driven propulsion.” From .
The key technical developments he is talking about are phased array lasers (of interest for communications weapons) and wafer scale photonic spacecraft.
The envisioned design is a giant laser (on Earth or near Earth space), which accelerates small spacecraft (a few mm^2) with a small laser sail (~1 m). The spacecraft could possibly return data at Mbs, depending on the design.
His paper is filled with details of the physics of these materials and systems, demonstrating that it is technically feasible (if difficult) to launch and accelerate small spacecraft to a significant fraction of light speed (~0.2 c), such that they could reach nearby stars in a few decades. (These probes have no ability to stop or return, so the missions will be flybys.)
Building such a large laser is challenging, but at least believable. The power consumption would be huge, though it only needs to operate a few minutes for each launch. So it could be used to launch a spray of thousands of probes, assuming power is available.
The tiny 1 gram spacecraft are a challenge, but prototypes exist today. Of course, they must survive huge acceleration and years of travel through harsh conditions, and operate completely autonomously–and then know to wake up and collect data for an hour or two once at the target. All on a tiny, single board. They also will need enough power to keep going and a lot of power to send back data.
Still and all, the point is that it is starting to be “thinkable”. And Lubin wants to start thinking very seriously.
While this is yet another Internet billionaire private space program, this one makes a heck of a lot more sense than low orbit shuttles or humans to Mars. This one could actually work!
- Philip Lubin, A Roadmap to Interstellar Flight. submitted Journal British Interplanetary Society, 2016. http://arxiv.org/abs/1604.01356