Developing ecospheres on transiently habitable planets: the genesis project

Abstract

It is often presumed, that life evolves relatively fast on planets with clement conditions, at least in its basic forms, and that extended periods of habitability are subsequently needed for the evolution of higher life forms. Many planets are however expected to be only transiently habitable. On a large set of otherwise suitable planets life will therefore just not have the time to develop on its own to a complexity level as it did arise on earth with the cambrian explosion. The equivalent of a cambrian explosion may however have the chance to unfold on transiently habitable planets if it would be possible to fast forward evolution by 3-4 billion years (with respect to terrestrial timescales). We argue here, that this is indeed possible when seeding the candidate planet with the microbial lifeforms, bacteria and unicellular eukaryotes alike, characterizing earth before the cambrian explosion. An interstellar mission of this kind, denoted the 'Genesis project', could be carried out by a relatively low-cost robotic microcraft equipped with a on-board gene laboratory for the in situ synthesis of the microbes.We review here our current understanding of the processes determining the timescales shaping the geo-evolution of an earth-like planet, the prospect of finding Genesis candidate planets and selected issues regarding the mission layout. Discussing the ethical aspects connected with a Genesis mission, which would be expressively not for human benefit, we will also touch the risk that a biosphere incompatibility may arise in the wake of an eventual manned exploration of a second earth.

Universal scaling relation for magnetic sails: momentum braking in the limit of dilute interstellar media

“…The launch requirements of such a craft would be furthermore compatible with the specifications [27] of the directed energy launch system envisioned by the Breakthrough Starshot project [11] for Centauri flybys, which could hence see dual use. The extended cruising time of the order 10 4 years implies however that slow cruising trajectories are only an option for mission, such as for life-carrying Genesis crafts [12], not expected to yield near-term results in terms of a tangible scientific return. as the inner magnetic field strength and the working-regime current I wr from (16).…”

“…For the first two options momentum is transferred to charged particles, with the difference being that the particle density of stellar winds is somewhat higher than that of the interstellar space. Passive deceleration of interstellar crafts is both suitable and necessary for interstellar missions for which the overall duration is irrelevant [12], such as missions aiming to offer life alternative evolutionary pathways [17][18][19].…”

“…The possibility to explicitly optimize the performance of the sail, i.e. the effective reflection area (8), has allowed us on the other hand to show that interstellar missions not limited by time constraints [12] are feasible. Passive deceleration using magnetic sails is in this case possible with low-mass crafts.…”

“…The ever longer list of known exoplanets [8] includes by now nearby potentially habitable planets [9,10]. The number of promising interstellar mission concepts is likewise increasing, ranging presently from high speed Proxima Centauri flybys [11] to slow cruising Genesis missions aiming to establish autonomously developing biospheres of unicellular organisms on transiently habitable exoplanets [12]. These developments warrants hence to reexamine the options available to decelerate the interstellar probe passively on arrival.…”

Why planetary and exoplanetary protection differ: The case of long duration genesis missions to habitable but sterile M-dwarf oxygen planets

“…Operationally, instead of landing, the Genesis probe would carry out the seeding process from orbit via the retrograde expulsion of micro-sized drop capsules. The goal would be in the end to lay the foundations for a self-developing ecosphere of initially unicellular organisms [35].…”