LET “Blast!” be a warning about the perils of nepotism.

In the documentary, director Paul Devlin follows his brother, Mark, as he and a team of fellow scientists try to launch a telescope on a high-altitude NASA balloon, the better to learn the secrets of the universe.

An interesting idea, to be sure, and, presumably, full of drama. Unfortunately, “Blast!” is dry and flat, and conveys none of that drama, or much of anything else.

If you really have a need to see “Blast!” wait for it to find its rightful place on cable.

Running time: 74 minutes. Not rated (could put you to sleep). At Cinema Village, 12th Street, east of Fifith Avenue.