While NASA has dedicated hundreds (if not thousands) of scientists and engineers to ensure that the future humans traveling to Mars make it back to Earth in one piece, they have paid a lot less attention to the fact of them getting homesick.
In order to help lift their spirits (and perhaps counter cabin fever) NASA is considering building a "Second Life" virtual world that would enable them to communicate with friends and family.
Suppose you're sending a "generation ark" to a remote star system. Why even bother letting the crew know? Surely they'd opt for VR decadence instead of the grinding boredom of workaday ship-board life.
For illustrative purposes, here's a brief excerpt from a story I began in 2003:
Inside, the crew stirred within their communal environmental VR, roused by an unspecific sense of incipience. Zack felt it in the air, a certain heaviness that descended over the spires and narrow, cobbled avenues. The hairs on the back of his neck prickled as he stood in front of the noisy café. As he watched, the faces of onlookers morphed into pixilated anonymity. He experienced a rush of strange nostalgia as the sky over Prague grew metallic, strewn with listing spheres and half-glimpsed workstation icons. His muscles tightened and the noise of conversation and scuttling cars blurred into the sound of electronic surf, pounding endlessly against the shores of his consciousness.
A blare of synthesized instruments. Prague had redshifted to a niggling afterimage, and he was alone in a strange green room that smelled of discreetly rotting vegetation. A barbed device, looking something like a spider as conceived by an aspiring surrealist, detached itself from his scalp, leaving a constellation of reddened impressions.
A voice: familiar, unwanted: "Welcome home, Zack."
He sagged into a mattress of gengineered lichen that buoyed his limbs and spine as if offering him up for sacrifice. His ears buzzed. He could still taste coffee. The spider-interface dangled above his head, twinkling mockingly in the glow of the room's diagnostic screens.
"Lights," he heard himself say. "Turn on the damned lights."
The room erupted in yellow light, emitted from organelles embedded in the walls and ceiling. The room was alive; in fact, it appeared to have grown more verdant in his long sensory absence. He breathed a quiet sigh of relief. There had been fear of native biota wrecking the Isis' genetic architecture, leaving the ship an undifferentiated blob of metal and biomass hovering between stars.
Elsewhere, he knew -- or, more accurately, sensed -- his crewmates awakening in dimly glowing rooms of their own. The metal spider curled its limbs into a somehow dangerous-looking sphere and drifted on a tether of fiber-optic cable. For the first time, he noticed the microgravity; the only thing keeping him from ascending was the mattress' faintly adhesive embrace. He freed his arms and watched his thin, colorless hands with the studied patience of a forensic scientist happening across some vital and mysterious piece of evidence.
He hadn't used his body in . . . 203 years, ship time? Unless something had gone wrong . . . But the voice had said "welcome home," hadn't it? A chill raced down his spine as he considered the possibility of software corruption. Two centuries of exposure to interstellar space could have plunged the AI into a lethally premature senility.