Planetary targets for the various Arks

Ark I - primary target: Alpha Centauri. Mission status - successful. Ark landed as designed. Viable colony established. Until they were decimated by a civil war and exterminated by the indigenous Piranha Rats.

Ark II - primary target: Tau Ceti. Mission status - ultimately successful after a delay of 14 centuries. Ark landed using atypical method (PPT tunnel punch-through). Viable colony established among already established indigenous population.

Ark III - primary target: 82 G. Eridani. Mission status - primary target had no habitable planets. Secondary target: Tau Ceti. Mission status at secondary target - partially successful. Crew compartment damaged. Able to land but several crew members killed and cargo compartment lost. Viable colony established although small subset was obliterated due to an asteroid strike.

Ark IV - primary target: Nu² Lupi. Mission status: unknown.

Ark V - primary target: Chara. Mission status - primary target had no habitable planets. Secondary target: Solar system. Mission status at secondary target - partially successful. Viable colony established and enhanced by capture and taming of indigenous population. Ultimately, untamed masses exterminated original colony.

So... what ever did happen to Ark IV? You'll find out in 2014 in the novel entitled The Milk Run.