Zo was not convinced. But their deceleration brought them into the Jovian system, where she would have a chance to put Jackie’s theories to the test. The ship ran a cat’s cradle through the Galileans to slow down further, giving them close-ups of the four big moons. All four of them had ambitious terraforming plans, and had started to put them into action. The outer three, Callisto, Ganymede, and Europa, had similar initial conditions to deal with; they were all covered by water ice layers, Callisto and Ganymede to a depth of a thousand kilometers, Europa to a depth of a hundred kilometers. Water was not uncommon in the outer solar system, but it was by no means ubiquitous either, and so these water worlds had something to trade. All three moons had large amounts of rock scattered over their icy surfaces, the remnants of meteoric impact for the most part, carbonaeous chondrite rubble, a very useful building material. The settlers of the three moons had, on their arrival some thirty m-years before, rendered the chondrites and built tent frameworks of carbon nanotube similar to that used in Mars’s space elevator, tenting spaces twenty or fifty kilometers across with multilayered tent materials. Under their tents they had spread crushed rock to create a thin layer of ground— the ultimate permafrost— in some places surrounding lakes they had melted into the ice.

On Callisto the tent town built to this plan was called Lake Geneva; this was where the Martian delegation went to meet with the various leaders and policy groups of the Jovian League. As usual Zo accompanied the delegation as a minor functionary and observer, looking for opportunities to convey Jackie’s messages to people who could discreetly do something about it.

This particular meeting was part of a biannual series the Jovians held to discuss the terraforming of the Galileans, and so a good context for Jackie’s interests to be expressed. Zo sat at the back of the room next to Ann, who had decided to sit in on the meeting. The technical problems of terraforming these moons were big in scale, but simple in concept. Callisto, Ganymede and Europa were being dealt with in the same way, at least at the beginning: mobile fusion reactors were out roaming their surfaces, heating the ice and pumping gases into early hydrogen/oxygen atmospheres. Eventually they hoped to create equatorial belts where gathered rock had been crushed to create ground over the ice; atmospheric temperatures would then be kept near freezing, so that tundra ecologies could be established around a string of equatorial lakes, in a breathable oxygen/hydrogen atmosphere.