Images of breathtaking natural landscapes transition into the dramatic launch of a space rocket. Onboard are three brave astronauts: Jim Pruett, Clayton Stone, and Buzz Lloyd. Meanwhile, back at mission control, Charles Keith grapples with the daunting question of whether they can execute even the simplest tasks after eight months in the vastness of space.
Once aloft, the astronauts remove their helmets, a sign of a troubling development as their backup systems mysteriously fail. Realizing the severity of the situation, Keith makes the crucial decision to abort the mission. A journalist, Vincent Van Lynn, sheds light on the intricacies of retro-fire and their expected return. The Mission Director, played by George Gaynes, asserts the urgency of employing their primary thrust due to the damage sustained by their secondary system. The communications officer, Tom Stewart, relays this critical message to the astronauts who are now facing an impending crisis.
As a tropical storm threatens to complicate their situation, the weather specialist, George Smith, warns that conditions are deteriorating. Faced with dwindling oxygen supplies, Keith reluctantly declares a 48-hour countdown for a rescue attempt, despite knowing only an untested aircraft and an inexperienced crew are available. He sternly advises against any reckless actions, particularly in attempting unauthorized repairs on the spacecraft.
In a moment of tension, the astronauts resort to taking sleeping pills, hoping that reduced movement can help conserve their precious oxygen reserves. Meanwhile, the wives of the astronauts arrive for an emotional farewell. Celia Pruett](/actor/lee-grant) struggles to express her love for Jim amidst the weight of practicality, focusing instead on insurance and their home. Teresa Stone conveys her support for Clayton's mission and hints at future aspirations, while Betty Lloyd tries to comfort the increasingly panicked Buzz as he spirals into a fit of hysteria, breaking down as he reads a letter intended for the President.
As bad weather hinders the launch of the rescue mission, Keith faces the media, dismissing inquiries about alternative plans. However, a new strategy begins to take shape as a computer technician, Bruce Rhodewalt, tirelessly works on a solution. Meanwhile, the astronauts fight dizziness as their situation becomes increasingly dire.
The XRV, the mission's last hope, is launched, igniting darker speculations about survival that hint at the unthinkable—sacrificing one to save two. Before any drastic measures can materialize, an attempt is made to fix the engine, but tragedy strikes when Jim’s suit sustains damage, leading to his untimely demise. Keith, burdened with the responsibility of delivering the dreadful news to Celia, feels the weight of their loss deeply.
As tension escalates, a nervous VIP, George R. Robertson, awaits updates. With rescue finally on the horizon, Buzz and Clayton make a desperate bid to open the hatch, despite Huston’s objections. In a pulse-pounding moment, Clayton pushes Buzz towards the escaping horizon, but in the chaos, he loses his grip and falls back into the rocket.
However, hope flickers as Ted Dougherty succeeds in rescuing Buzz, while another astronaut provides oxygen to the recovering Clayton. Against all odds, both men emerge from the harrowing experience alive as the story unfolds in a gripping tale of courage, sacrifice, and emotional endurance.
