Hogwarts in space? Starfleet Academy for kids. The big-screen adaptation of Orson Scott Card’s 1985 sci-fi novel, “Ender’s Game,” is a little of both and not enough of either.

British teen actor Asa Butterfield plays Ender Wiggin. Ender, who’s 12 in the story, is singled out by Col. Hyrum Graff of Earth’s International Military as the boy most likely to defeat aliens called the Formics.

Fifty years ago, the insect-like Formics invaded Earth. They were beaten back by legendary International Fleet Commander Mazer Rackham. Since then, Earth’s military minds have been preparing for the next Formics invasion that they believe will inevitably come.

Anticipating the invasion, the military trains children to be its future warriors in space. Most importantly, the search is on for the genius who can lead Earth’s forces to victory.

Harrison Ford plays the single-minded Col. Graff in sometimes wry but usually deadly serious mode. Ford’s character is a bit confusing, a mix of loving grandfather and taskmaster who gives no quarter. Col. Graff’s constant counterpoint is Maj. Gwen Anderson, Battle School psychologist.

Harrison, despite his character’s contradictions, gives the best performance in “Ender’s Game.” Viola Davis and her fretting Maj. Anderson are overwhelmed by Harrison’s old warrior.

The lack of passion in Davis’ performance echoes throughout “Ender’s Game.” The game keeps its distance. A good-looking exercise, it contains much computer-animated hardware and battles but little heart.

Nonetheless, Butterfield (Martin Scorsese’s “Hugo”) rises to the occasion as Ender, the prodigy picked by Col. Graff to end the Formics threat. Butterfield’s Ender is convincingly smart, thoughtful and mature beyond his years. The actor also embodies seriousness that suggests Ender can carry the weight of the world on his small shoulders. And the kid commander has amazing focus.

But Ender also is small, skinny, sensitive — a natural bully target. His knack for strategy, however, a talent Col. Graff admires, often gets him off the intimidators’ hook. Despite the series of bullies Ender meets, there’s little payoff in the movie’s smart kid vs. bullies scenes.

With few adults around, on Earth or in space, the ensemble cast of largely young actors in “Ender’s Game” includes Hailee Steinfeld, the actress who earned an Oscar nomination for her role as the girl determined to bring her father’s killer to justice in 2010’s “True Grit.” Steinfeld plays Petra, Ender’s early ally in Battle School.

Another young Oscar nominee, Abigail Breslin, co-stars as Ender’s sister. And Oscar winner Ben Kingsley shows up as the curiously odd hero of the first Formics war.

“Ender’s Game,” even with its exceptional cast and big battle scenes, doesn’t engage in an emotional, suspenseful way. Rather than rouse passions, the film’s dispassionate sci-fi action and Earthly melodrama fosters a grim, cold feeling.