I sometimes wonder who TV execs think their audiences are, especially when it comes to sci-fi. By its very nature, it should mainly appeal to intelligent people who are interested in the bigger picture; in science and the direction society is heading. To a certain extent, the same could be said for fantasy, but it is sci-fi that usually addresses society's faults and its dreams by looking at potential future scenarios.

A lot of people, as in hardcore sci-fi fans, believe that Star Wars was the worst thing that happened to the genre, bringing it to a mass market that was more interested in action than concepts. OK, the whole Force thing had some mystic overtones, but this was of little interest to the majority that were infatuated with light sabres and slave Leia. As a result, film and TV studios wanted to replicate Lucas's success by sticking to a similar formula.

In recent years we have seen many smart sci-fi shows for grown ups cancelled, often at a crucial part of the story, or even before a season finishes. For most people Firefly is the most memorable of the shows cancelled mid season, but there were others such as Odyssey 5 and Threshold that suffered the same fate. Then there was Stargate Universe (probably the best of that franchise) that only managed two seasons before being axed. The list goes on and on.

There is a new entry to that list, Defying Gravity, which first aired in 2009. Only 13 episodes were made of this gripping space drama, from the producers of Grey's Anatomy. The series revolves around the eight astronauts and the ground crew of the Antares and their six-year mission, which includes landing on Venus. However, the complete details of the mission are not revealed to the crew, and when they start to hallucinate they begin to demand answers, giving a flavour of Solaris and Event Horizon.

It's a slow burner, and flips back and forth through different time periods to develop the characters' back stories as well as that of the mission. It's a good six episodes before the drama starts to ramp up, but it is worth the wait. The cast is full of familiar faces who bring the characters to life, so that you care about all their foibles.

The story doesn't get resolved but the journey is a good one and well worth going along for the ride, as it addresses many interesting cosmological questions.

Defying Gravity is out on DVD from February 25.