Documentaries about NASA are not scarce, but Discovery Channel's "When We Left Earth: The NASA Missions" (9 tonight and June 15 and 22) paints its tale on a broader canvas.

This isn't a narrow focus look at the Apollo program, it's an overview of NASA through its entire 50-year history. Taking that approach, "When We Left Earth" can't help but skim the surface of that history over its six-hour running time (two hours air each Sunday).

Although a wide array of former astronauts and NASA personnel are interviewed for "When We Left Earth," the HBO docudrama miniseries "From the Earth to the Moon" still gives the best sense of NASA culture.

But for space junkies with high definition TVs, Discovery Channel's new program will be a must-see event. Producers combed through more than 500 hours of footage and transferred more than 100 hours into HD. (Discovery will donate a copy of the HD footage back to NASA.)

Tonight's first hour, "Mercury: Ordinary Supermen," details the selection of the first astronauts and offers quick descriptions of each (John Glenn is deemed "the most level-headed"). By the end of the hour four missions have launched. Not that it needs much help with so much to cover in so little time, but pulse-pounding music with a constant sense of urgency propels the series forward.

By episode five, "The Shuttle" (9 p.m., June 22), it's 1977 and the space shuttle is having its first tests. The first shuttle commander, John Young, says, "Anybody who thinks they can statistically predict when something with 2 million moving parts is gonna fail is smoking something they shouldn't be probably."

Although clearly an ode to the men and women of NASA -- narrator Gary Sinise, one of the stars of "Apollo 13," describes NASA's history as "the story of our greatest adventure" -- "When We Left Earth" doesn't skirt the failures.

"NASA was arrogant," says journalist Jay Barbree, who has covered the space program since its inception. "They thought they couldn't do anything wrong."

The program immediately cuts to the image of doomed teacher-in-space Christa McAuliffe preparing for the disastrous Challenger flight. Much of "The Shuttle" is devoted to the Challenger tragedy and the series' final episode, "A New Space Age" (10 p.m. June 22), chronicles the Columbia breakup on re-entry.

Aside from some little-seen footage and the HD appeal, "When We Left Earth" doesn't break new ground, but it repackages the history of America's manned space program in spruced-up, easy-to-digest form.

Maudlin 'Army Wives' back for second season

Lifetime's "Army Wives" (10 tonight) returns for its second season with an episode that's equal parts maudlin platitudes and genuine, sad-tinged surprise.

It picks up where the first-season finale ended with a bang as a bar exploded with many characters inside. Tonight's premiere doesn't reveal the fates of all involved immediately and instead laces in the syrupy observations of Pamela (Brigid Brannagh) who uses her radio show to talk through her upsettedness.

"What is it about the human touch?" she asks, channeling Marin Frist (Anne Heche) from "Men in Trees." "Holding a loved one close and feeling their heartbeat."

The episode has way too much of this treacly sentimentality, although it shakes it off for a curve ball conclusion.

Roxy (Sally Pressman), always the show's most vivacious character, frets over the lack of contact with her deployed husband (Drew Fuller). Lt. Col. Joan Burton (Wendy Davis) must decide what to do about her pregnancy while her unfaithful husband (Sterling K. Brown) recovers from the bombing.

"Army Wives" has always reminded me of "The Unit," but it flips the primary and secondary stories to concentrate on the wives rather than the soldiers. It's a fine summer soap, a guilty pleasure, but nothing more than that.

Of local note: This season Pittsburgher Katelynn Pippy takes over the role of Emmalin Holden, youngest daughter of Kim Delaney's character, Claudia Joy.