chemicals. By selecting and mixing them together in various proportions, different levels of thrust are attainable from the RX-M's engines. The crew ladder ends at a round pressure hatch in the middle of a bulkhead floor that leads to the crew's upper living and control compartment. Instruments and technical equipment were supplied by Allied Aircraft Company of North Hollywood. Historical and factual accuracy The five Mars explorers wear U.S. military surplus clothing, including overalls and aviator's leather jackets. It has been noted in other film reviews that the explorers are wearing gas masks, but gas masks would include goggles to protect the eyes. Due to the thin Martian atmosphere, the explorers are actually wearing military "Oxygen Breathing Apparatuses" (OBA) like those used by military firefighters. Various scientific curiosities and errors are seen during the film: With less than 15 minutes to go until launch, the RX-M's crew are still in the midst of a leisurely press conference being held at a base building. From its launch pad, the RX-M blasts straight up, and once it leaves the Earth's atmosphere, the ship makes a hard 90-degree turn to place the RX-M into Earth orbit. Its speed at an altitude of 360 miles is stated to be ; in fact at that height orbital velocity is (though escape velocity is approximately correctly stated to be ). Simultaneously with that turn, the crew cabin rotates within the RX-M's hull, around its lateral axis, so the ship's cabin deck is always facing "down", orienting the audience. Though objects are purposely shown to float free to demonstrate a lack of gravity, none of the five crew members float, apparently unaffected by weightlessness. The RX-M's jettisoned first stage, with its engine still firing, and a later meteoroid storm (inaccurately referred to in dialog as meteorites) both make audible roaring sounds in the soundless vacuum of space that can be heard inside the crew compartment. The clusters of those fast moving meteoroids appear identical in shape and detail (actually, the same prop meteoroids were shot from different angles and positions, then optically printed in tandem, at different sizes, on the film's master negative). A point is made in dialog that the RX-M is carrying more than "double" the amount of rocket fuel and oxygen needed to make a successful round trip and landing on the Moon; while impractical for various reasons, this detail becomes a convenient, then