The first manned expedition to Mars is decimated by an unknown life form... which stows away on the rescue ship.

This film's claim to fame is that it inspired "Alien". And you can sort of see the similarities, or at least the general plot: after landing on an alien world, explorers from Earth unknowingly pick up a deadly creature that hopes to kill them all. Beyond that, it is completely different.

The film has its level of "cheese", with people smoking on a spaceship (which seems like a bad idea, but I guess you could smoke on airplanes so maybe it made sense). The alien is obviously a man with a rubber suit. And the way they walk outside the ship in zero gravity... But I think it still ranks a cut above many (or most) of the science fiction films of its day. Even the design of the ship seems like it took a fair amount of effort.

John Carpenter claims the film was shot in six days. I am not sure how Carpenter knows this, but if it is true we could perhaps give them even more credit: this is a production above and beyond the average quickly-produced garbage.

Col. Edward Carruthers(Marshall Thompson)loses his crew to an alien monster than drains it's victims of their blood and water(even from the bone marrow and tissue)during an expedition on Mars. A second space vessel, one of rescue when the first ship crashes on Mars, picks up Carruthers who is not believed by anyone including his government back home that an alien monster killed his crew. That is until, they themselves are being killed one by one after the monster found a way into their ship on it's way off Mars to Earth. It seems almost indestructible after countless attempts by the crew to kill it with grenades and guns. Somehow the crew will have to find a way to destroy it as the monster holes them up on the bridge after getting through their first two department levels. What's even worse is that two of the crew, including leader of the rescue mission, Col Van Heusen(Kim Spalding),are attacked by the creature with a bacterial infection spreading into their bone marrow. Another crew member, Lt. James Calder(Paul Langton)is stuck in the lower engineering room with the monster after he and Carruthers attempt to electrocute it. Hiding between the Induction pumps which make the ship land properly and orbit safely, Calder keeps a blowtorch at it's eyes not allowing it to get him(..although, his leg is broken). That presents a problem in itself..if that creature were to attack the equipment in that engineering area, the space ship would not be able to land, but merely drift in space. And, to add to all this, a sick and jealous Van Heusen(he's in love with Ann, played by Shirley Patterson, who is bonding with Carruthers)unshields the reactor hoping radiation will kill the monster who is caught in the room with it after Carruthers closes the hatch to that specific room. Now, the crew, or who's left of them, will have to figure out a way to stop the creature with most of the ship full of radiation! A possible solution, regarding the monster's desperate need of oxygen due to it's huge lungs, may be the crew's only means of harming it.

Despite being dated and low-budget, this sci-fi thriller is a winner. The idea of a crew having to match wits with an almost unkillable alien beast adds a great deal to the film even if the monster is merely a man in a hideous rubber suit. I credit director Ed L Cahn and writer Jerome Bixby for creating a tense situation which is pretty much "The Thing from Another World" set in a space ship. Still, that whole "race against time" angle along with the idea of "having few places to run" just makes this little B-film a must for fans of 50's creature features. Cahn and Bixby create an intelligent flick that makes up for the budgetary constraints with taut situations where these characters have to come up with ways to combat their predator when options are limited. Highly recommended. It's clear when you watch this flick how much Ridley Scott's "Alien" was inspired by it.

The "Fun Facts" section on the back of the Midnite Movies DVD proudly exclaims that this film formed the main inspiration for Ridley Scott's film "Alien". I find this quite a remarkable little trivia detail, as "Alien" is generally – and deservedly – regarded as one of the greatest and most legendary milestones of Sci-Fi cinema and, if the premise of such a classic is inspired by a cheap and typically 1950's monster mania flick, than it means that this source of inspiration must be an underrated and overall very decent film. Of course, being the blueprint for "Alien" has to be put into perspective just slightly. I think we can all safely agree that the rudimentary plot of Scott's film is the least impressive aspect about the entire production. Hideous and invincible extraterrestrial monster gets aboard a spaceship and kills off the astronauts one by one. That's basically it and that's also all that "Alien" has in common with "It! The Terror from beyond Space". "Alien" promptly became an immortal classic thanks to the Ridley Scott's unique talent of building up claustrophobic suspense, the titular creature's nightmarish design and the flawless acting performances of the entire cast (including Sigourney Weaver, John Hurt and Ian Holm),whereas "It!" simply stayed a charming but nonetheless fairly insignificant 50's monster movie. Still, I wouldn't hesitate recommending this movie to fans of nostalgic Sci-Fi, as the action is fast-paced, the characters are likable and the guy-in-the-rubber-monster-suit is highly memorable. The story opens with a sinister voice-over intro – I love that – spoken in by Colonel Edward Carruthers; sole survivor of the very first manned mission to planet Mars. He awaits the arrival of a second spaceship that will take him back to earth AND to court marshal. Nobody believes Carruthers' story about an unconquerable Martian killing off his crew and he will have to stand trial himself. The nine-headed crew of the second mission will soon be able to defend Carruthers' story, as the unnamed monster sneaks aboard and turns the voyage back to earth into a deadly ordeal. Obviously almost every aspect of the film has dated severely by now (not just the special effects but also, for example the role of women in science) and the script is crammed with hilarious improbabilities (the monster dodges bullets and even grenades, but it's petrified of a tiny little flame?) The acting performances are way above average for that time, with particularly Marshall Thompson and Shirley Patterson shining like stars. Recommended