CRIRES model-based computer-generated impression of the Plutonian surface, with atmospheric haze, and Charon and the Sun in the sky. Pluto’s atmosphere consists of a thin envelope of nitrogen, methane, and carbon monoxide gases, which are derived from the ices of these substances on its surface.
The Pluto–Charon system is noteworthy for being one of the Solar System’s few binary systems, defined as those whose barycenter lies above the primary’s surface (617 Patroclus is a smaller example, the Sun and Jupiter the only larger one). This and the large size of Charon relative to Pluto has led some astronomers to call it a dwarf double planet. The system is also unusual among planetary systems in that each is tidally locked to the other: Charon always presents the same face to Pluto, and Pluto always presents the same face to Charon: from any position on either body, the other is always at the same position in the sky, or always obscured.
Researchers in the UK, USA, Italy and the Netherlands are working on a “living spaceship” to launch in 100 years. The self-sustaining spacecraft will rely on biotechnologies to carry people beyond our Solar System. Organic matter, algae, artificial soil, production of biofuel and sustainable foods are all part of the plan.
The project, dubbed Project Persephone, is part of Icarus Interstellar, a nonprofit foundation aiming to achieve interstellar flight by 2100. Other projects include Icarus (an unmanned fusion-powered interstellar probe), Helius (an investigation of laser-initiated pulse propulsion), Tin Tin (a nanosat mission to Alpha Centauri) and Forward (a beamed energy/sails initiative for interstellar propulsion).
Image: The Daedalus, another Icarus Interstellar concept (artist’s impression). Credit: David A Hardy