On the Threshold of Space is a drama that pays special emphasis to historical accuracy, honoring the men behind America’s first ventures into space. With input and assistance from the U.S. Air Force, the film follows an Air Force doctor as he conducts rigorous tests to determine how the human body will respond to the challenges of space travel. These include experiments such as ejection in a space capsule from 45,000 feet, rocket sled rides at 1,000 miles per hour, and ascents to 100,000 feet in a balloon. Throughout, the doctor's devoted wife stands by him, even when he risks his own well-being as a test subject. Cast: - Guy Madison as Capt. Jim Hollenbeck - Virginia Leith as Pat Lange (Mrs. Hollenbeck) - John Hodiak as Maj. Ward Thomas - Dean Jagger as Dr. Hugh Thornton - Warren Stevens as Capt. Mike Bentley - Martin Milner as Lt. Morton Glenn - King Calder as Lee Welch - Walter Coy as Lt. Col. Richard 'Dick' Masters - Ken Clark as Sgt. Ike Forbes - Donald Murphy as Sgt. Zack Deming - Barry Coe as Communications Officer - Dan C. Ogle as Himself - Prologue (as Major General Dan C. Ogle) Runtime: 98 minutes.