They state that Calvin was a carbon-based organism. That means that Calvin should have burned up when Rory Adams (Ryan Reynolds) tried to use a 'flame thrower' on Calvin.
As demonstrated by the fires on Apollo 1 and the Mir space stations, open flames are so dangerous they would NEVER be used inside the space station - for any reason.
Rory tries to kill "Calvin" with a handheld flamethrower. In a micro-gravity environment such as the International Space Station, and without any sort of anchor or tether having been attached, each time he fires a burst, Rory should be thrust backward, directly opposite his weapon's aim.
Given the concern about firewalls, it's unlike the CO2 system would 1) have outlets that needed to be closed one at a time, and 2) be interconnected to the main space station.
After Calvin crushes Dr. Derry's hand it just hangs limply to show that it has been severely broken. Since they are in a "zero G" environment his hand should actually float along like the rest of his body.
Officials back on earth are obviously very concerned about aliens returning to earth and would have procedures in place to destroy the lifeboats before they landed.
In the opening scene, the view of outer space from the International Space Station shows twinkling stars. Stars do not actually twinkle in the way we see them, but the twinkling is an optical illusion of the light from stars being refracted by the earth's atmosphere.
David's pod couldn't have survived re-entry on its own as earlier Miranda has disabled the David's pod automatic flight plan back to earth thus giving him manual control. Re-entry is a complex maneuver that requires computer assistance and control along with complex calculations and specific set of re-entry angle. Just using a joystick to control the pod wouldn't work on re-entry as slight deviations will cause the pod to breakup or simply bounce back up to space.
Given the concerns about isolating the lab from the main space station, it's probable that they would have protocols in place that specifically required them to leave injured or "contaminated" astronauts in the lab in case of containment breaches.
Much like in 'Gravity' everything is moving around as if it had little or no mass. Navigating a human body in micro gravity is a difficult task and must be done with great care. In this movie (as in others) these guys a flitting around like squirrels stopping their motion and changing direction effortlessly. In real life moving at those speeds would cause serious injury. A few times they even stop without grabbing anything. A related annoyance is the way the doors manually open and close effortlessly in no time at all as if they are made from nothing. Still, they manage to keep the creature out.
When they are attempting to revive the man, they get a pulse back and someone says, "we have a pulse. Sinus brady, 98bpm." Brady is short for bradycardia which always indicates a heart rate of <60bpm (beats per minute). So if their bpm is 98, it would not be sinus brady, it would be Normal sinus rythm.
Despite moderate quantities of blood floating around following deaths, none of it splashes onto surfaces.
Some of the labels in Russian are incorrect. Miranda North's shield is literally translated into Russian as "Miranda Sever" (of course, in Cyrillic variant of this spelling). However surnames are not translated, and the shield in Russian should be either "Miranda Nors" or "Miranda Nort" (depending on the tradition of spelling English "th"). Also "Celsius" on temperature detectors was translated as "Celsiyu" (in Cyrillic; that means "by Celcius"); the real detector would be labeled as just "ºC".
At one point the space stations orbit is degrading and the thrusters are fired to put it back into a stable orbit. To accomplish this the thrusters seem to fire down or towards the earth, this is incorrect, to gain altitude they would need to orbit faster so the thrust would be from the back accelerating them into a higher more stable orbit.
The pod in which the Calvin is entrapped has the oxygen vented from it so that it is a vacuum inside the module. Assuming Sho Murakami could even have opened the door, the explosive force of the oxygen entering the module should have blasted him across the room and either killed him or severely injured him when he struck the other end of the module.
The ISS is sealed. Unless someone opens a hatch, there is no way for Calvin to enter. It doesn't matter if they are out of fuel, the organism isn't going to go in through the thrusters, through the empty fuel tank, and into the habitation areas. It would need to open a hatch, or rip through something.
As in many science fiction and horror films, the catastrophic depressurization of the International Space Station is vastly, unrealistically drawn out for dramatic effect. In a real situation, such implosive decompression would occur within a few seconds, not a minute or even more.
The I.S.S. is pressurized to an internal rating of about 760 Torr, or the same as the average at sea level upon the Earth. In Low-Earth Orbit, the I.S.S. is subjected to an external vacuum (negative pressure) of around 10^-7 Torr. The pressure differential therefore equates to 7.6 million times more atmosphere inside the I.S.S. than outside.
Even the smallest micrometeorite strike penetrating the hull of the I.S.S., or the failure of one of its panels, joints or valves would cause complete atmosphere evacuation before the crew would even realize what had happened, let alone be able to respond to the event and rectify the problem.
At the beginning of the film, Ryan Reynolds goes outside to manually capture the probe returning from Mars. Given the actual speed of the probe is greater than the speed of the Space station, it would have been impossible for him to see let alone capture the probe.
The astronaut "North" has her name in Russian below her English name. It is shown translated as the Russian word "Sever" which means the direction North. A name would surely be translated phonetically into Cyrillic, not fully translated into its Russian equivalent. This would look more like "HOPO" (with a vertical line through the last "O" to give the character for "F" (closest to "th" in Cyrillic).
Right after Rory tells Hugh 'you are gonna be a father', Hugh leans back and his hands are NOT inside the gloves he is using to get Calvin to react.
At the beginning of the film, sounds can be heard when the Pilgrim capsule is hit by debris, and other sounds can be heard in other scenes in the Space. In the Space, there's no air and so sound waves cannot propagate.
Soyuz spacecraft take at least six hours to reach the International Space Station, rather the hour or so shown in the movie.
The movie shows "Calvin" being attracted to and consuming oxygen from the lures they used to get it to the lifeboat as well as stating many times that since it is carbon-based, it needs it the way humans do. "Calvin" is from Mars where the atmosphere is 98% carbon dioxide. While there wouldn't be enough oxygen on modern Mars for the survival of the creature, it's explained throughout the film that it had been hibernating for possibly millions of years, since a period in which Mars had higher oxygen levels.
Venting oxygen would create thrust that would change the station's orbital trajectory.
The film has the astronauts screw up the trajectory while playing with the thrusters - but ignores the thrust created by the venting.
In early scenes, Sho's wedding band is very thin. When he is trapped in the sleeping pod, it is noticeably wider and thicker.
The crew spend much of the second half of the film trying to trap the alien and vent the atmosphere from around it to kill it / suffocate it as the repeatedly state it is dependent on oxygen. This ignores the fact the alien spent much time outside of the space station earlier in the movie with no ill effects.
The crew attempts to kill Calvin by venting all oxygen to space. While the creature does survive for a few minutes outside the ship, it's explained that it needs oxygen for longer periods and would have eventually died outside the station.
When David takes manual control of the life boat to steer it towards deep space, the display already shows the trajectory for the override before he touches the joystick.
Early in the film Dr. Jordan (Gyllenhaal) is depicted floating weightlessly through the space station carrying his electronic tablet/device in his hand. At one point, when he sets his tablet down on a nearby workstation, the way the corner of his tablet drops from his hand reveals that he is obviously in a gravity environment where the tablet actually has weight.
Ekaterina (Kat) sacrifices herself to stop the creature getting inside. But she misses the obvious option of pushing herself and the creature into space while it is attached to her.
"Calvin" is shown to possess a remarkable ability to move quickly, efficiently and accurately throughout the International Space Station, a near-zero "micro-gravity" environment. Even though Calvin's home planet of Mars has only 38% of Earth's gravity, it would still be impossible for an indigenous organism to adapt so quickly to such foreign environs.
Kalvin feels so much cold at habitable for humans, cold environment (arround freezing point), that it sticks to the torches. However, in space the temperature is -270 °C (0 K or -450 °F) and it spent there quite a lot of time, while it was "running" outside the space ship. At that temperature nearly all molecular motion ceases.
It would be elementary to have the 'quarantine lab' physically detached from the rest of the ISS. (Spoiling the plot, of course.)
For that matter, why not have an entirely separate laboratory? One not in danger of orbital decay.
The experiments done on the ISS could easily have been done by the Mars Lander that collected the samples. Experiments to find life on Mars were in fact done by Viking 1 in 1976, and viewed as negative.