Adding a propulsion system and navigation gear to the International Space Station (ISS) could turn the $156 billion orbiting laboratory complex into an interplanetary spaceship, a writer on space issues argues.

With 15,000 cubic feet of space, the ISS would have more room than the next-generation U.S. spaceship, the space capsule Orion, Michael Benson argues in The Washington Post.

Orion is being developed in the Constellation Program, along with the Ares rocket that will lift Orion into space.

At first, Orion would head to the moon, where a lander named Altair would touch down.

Orion won’t have a manned mission until 2015, or 2014 at the earliest, even if development work proceeds on schedule. A moon mission wouldn’t come until around 2020. A permanent encampment on the moon would come later still. And sometime in the distant future, perhaps in the 2030s, the United States finally might (with other nations helping to foot the bill) send a manned mission to Mars.

Benson wrote that that is a very long time to wait, when the ISS will be fully built in 2010, already there in space.

To be sure, he doesn’t propose killing the Constellation Program. Rather, he sees using Orion as a navigation and orientation asset for the ISS on an interplanetary voyage, with the Ares V heavy lift rocket bringing up the immense amount of supplies that the ISS would need for a voyage lasting the better part of two years.

Benson notes that the ISS isn’t shaped like a sleek rocket or space capsule.

But then, neither was the fictional Starship Enterprise.