An opening narration explains a panorama of a space station and attendant space craft under construction. It goes on to explain the station is used for both observation and construction of spaceships for the conquest of space.Opening sceneOn board the space station, the crew watches a transport ship approach the station. Barny Merritt (Eric Fleming) complains to his father, General Merrit (Walter Brooke) that he has been onboard the station known as the Wheel for a year without any leave, he requests he return to Earth on the approaching spacecraft. General Merrit denies the requestOn the rocket being constructed an accident occurs when Roy Cooper (William Redfield) becomes paralyzed while working with high tension cabling. The crewman is taken back to the wheel and is checked out after recovering. The doctor is satisfied he will recover in time. He confides with Capt Merritt that Cooper is suffering from space fatigue, and needs to be returned to Earth.In the rec area Cooper talks about the selection process that got them to on the Mars flight, Sgt Siegle argues that they may just be guinea pigs, and the real crew has not been selected. The six selected crewmen go to the mess hall. Their meal consists of various flavored tablets and waterAt dinner Sgt Mahoney (Mickey Shaughnessy) explains some of the history of General Merritt, and how his son is an ingrate. Suddenly the wheel is rocked by a concussion. It is reported a meteor hit the installation. Gen Merritt co-ordinates the stabilization of the wheel while damage control crews seal the leak Later, the cargo rocket arrives and begins transferring passengers including Dr George Fenton (William Hopper) The doctor meets Fenton.The space craft being assembled is a mystery. General Merritt thinks the ship is to go to the Moon, but is puzzled why it has wings. Fenton reveals the true destination of the ship is actually Mars. The general is furious about the change. He wanted to go to the Moon as a test run of the ships systems although he considers the mission dangerous, but accepts the command anyway. His son, hearing of the new mission requests his transfer be stopped. He wants to go to Mars with his father.The crew who have been building the ship are going to crew. Unfortunately their numbers have to be whittled down from the original 6 to 3. Merritt asks Siegle (Phil Foster), Imoto (Benson Fong) and Andre Fodor (Ross Martin) to seriously consider their options. The General thinks the mission is poorly thought out and doesnt hesitate to tell the potential volunteers.Imoto with an impassioned speech about the worlds need to find more resources agrees to go. Mahoney then volunteers, but is rejected by the general as being too old. Sanella and Siegle ultimately agree to go. Later the crew watch a tv broadcast from Earth, a special bulletin interrupts the show to announce the official launch of the ship to Mars. Then each of the crew receives a private message from a family member, Fodors mother speaking from Vienna wisher her son the best. Sgt Seigles girlfriend speaks next. She announcers her undying love for SeigleA few hours later the ship launches without incident and begins the year long voyage to MarsThe crew settles in, but they soon realize Mahoney has stowed aboard the ship. He is badly injured because of no acceleration chair; however he will survive his injuries. Gen Merritt expresses doubts to his son about mans role in space. As strong Christian he searches the Bible for answers, but finds little comfort in the passages he locates.Later in the flight, an external camera fails Siegle and Fodor are ordered to go outside and make repairs. While working on the camera a huge asteroid comes up on the ship from behind. The two men scramble to attach their safety lines as Merrit undertake an emergency maneuver to save the ship.Assuming the danger has passed the two men continue their work. Suddenly they see a series of flashes and pinging sounds around them. Before they realize the danger Fodor is hit by a micro meteor, screams and drifts away from the ship dead. Siegle is ordered to return to the ship leaving Fodor drifting in space.After some discussion the General decides to go outside and perform a space burial for Fodor. After reading passages from the Bible, he gently pushes the body away from the ship.As the voyage progresses the Generals actions become more erratic. During a routine report to Earth he snaps and begins screaming about the sacrilege of the voyage what an abomination the whole venture is.Capt Merritt reports that the General has been suffering very bad headaches and lack of sleep.Finally reaching Mars, the ship begins its landing. The General is piloting the ship at this stage, he suddenly has a vision, panicked he tries to abort the landing. Seeing the situation, his son overpowers him and completes the landing without incident.Safely down the crew wastes no time getting their suits on and exploring the planet. Imoto removes his glove and grabs a handful of soil. Letting it filter through his fingers he declares it good. He then produces some flower seeds and explains he was going to plant them. Behind them they hear huge amounts of fluid gushing from the ships engines.Merritt fears one of the pipes was ruptured during the landing Reaching the engine room Merrit finds his father is releasing the fluid, which turns out to be water. Gen Merrit fires at his son. A fight ensures in the cramped area and the General is shot and killed. Sgt Mahoney sees the end of the fight and thinks Capt Merritt shot his father intentionally and hopes a court marshal will be called for back on Earth.The crew buries the General and Imoto plants a seed on the grave. Because of the water lost, they face a critical shortage. Capt Merrit begins rationing immediately.The months drag on and the crew celebrates Christmas and moral is slumping due to a lack of water or contact with Earth. Mahoney dwelling on what he saw in the engine room; snaps and begins to believe the General might have been right and the planet along with the ship is cursed. Suddenly they see something outside and to everyone glee, its begun to snow. They set about collecting snow realizing their water shortage is now over.July comes, and it is time to prepare to leave. Imoto has spent his time collecting a large number of samples and remains convinced the planet can be agriculturally productive, especially after seeing one the seeds has germinated.An earthquake rocks the landing site, putting their intended launch time in jeopardy. The ship is now tilted incorrectly and needs to be straightened. By selectively firing the engines they believe they can shift the sand from under the ship and get it pointed correctly. The plan works seconds before they must take off.Excited Merrit fires the engines and the final scene shows the ship lifting into space