Space and Physics
PUBLISHED
A private company is aiming to launch a low-cost interstellar mission to Alpha Centauri, the nearest Sun-like stars to our own, in an attempt to tackle several key parts of the Fermi paradox.
The Fermi paradox, for those who haven't stumbled across it yet, is basically this: Given the large numbers of stars in the galaxy and universe, and the potential for life that they hold, why have we not yet detected any signs of intelligent alien life? Why the "great silence"?
While there are many proposed explanations for the Fermi paradox, varying in their levels of cosmic horror, there are a few simpler suggestions. One is that space is simply too big for interstellar travel to be feasible or desirable to intelligent species.
It is this argument that the team hopes to poke holes in, by making us become an intelligent species who desired to send a spaceship to another star system, and then doing it.
Missions to Alpha Centauri have been proposed before, including the Breakthrough Starshot mission, which aimed to head to the star system and photograph it before returning home. These mission proposals have generally focused on emerging technologies such as solar sails for propulsion, or electron beams, and are generally more long-term ideas rather than "strap in, we're going to Alpha Centauri".
With the Fermi Explorer, the team hopes to head to another star system using existing technologies, launching by 2029. In a new feasibility document outlining the mission, they explain that the spacecraft would use solar-electric thrusters expelling xenon to reach its target.
In the first stage, the spacecraft would take its time getting getting closer to our own star, reaching around 0.42 astronomical units (AU), with 1 AU being the average Earth-Sun distance. It will then take advantage of the Oberth effect, in which a spacecraft can accelerate as it is falling into a gravity well to gain kinetic energy more efficiently.
Spending around 12 years accelerating at the right time, the spacecraft will then be on course and at sufficient velocity to escape our Solar System and head to Alpha Centauri.
“Successive revolutions raise aphelion while the perihelion burns repeat, until the orbit reaches escape energy," the technical report explains.
There are of course a few trade-offs involved in such a mission, with the main one here being that it will take around 77,000 years to arrive at the destination.
It would also not have much of a scientific use, with the probe likely going out of contact with the Earth within a few years of its long journey. Any future humans capable of catching up with and recovering the probe would clearly be too advanced to need any information it could glean, anyway.
So, what is the point of the mission? Essentially, to draw a little more attention to the Fermi paradox, and challenge those key aspects of it.
If we choose to send missions to other star systems, and are capable of doing so for a low cost (the mission is currently looking to raise around $15 million for the spacecraft) then surely the cosmos should be littered with small probes, sent off on their own to explore other stellar environments?
Of course, you could argue that maybe it is filled with probes and we are not advanced enough to detect them yet. Or that while we may enjoy the novelty of sending one probe to Alpha Centauri, that's very different from an advanced species doing so on the regular, and across timescales where they could be found by other distant civilizations.
Perhaps civilizations always launch the one or two probes to a nearby star, but then get bored and move on to other projects?
Launching a spacecraft at Alpha Centauri is unlikely to rule out the "space is big" explanation of the Fermi paradox. But it would still be cool to know, no matter what happens with humanity, that we got at least one spacecraft to another star system. Even if it does take 77,000 years to get there.
