as long as they can hold their breath
If a human being exposed to open space without spacesuit, due to pressure difference he cannot breathe & within minutes he will die.
It can take 2 hours to put on a space suit.
Probably about 10 seconds of useful consciousness. Not a lot of time to rescue yourself. A good reason for using the buddy system whenever possible.
The oxygen supply in a spacesuit can last for about 8 to 9 hours, depending on the level of physical activity and breathing rate of the astronaut. It is important for astronauts to monitor their oxygen levels and regulate their activities to ensure they have enough oxygen to safely complete their tasks.
Without a spacesuit, airtight building or other breathing apparatus, a human could live for about 3 minutes on Mars. With the right equipment, a human can live indefinitely on Mars.
If you go into space without a spacesuit, you would experience a rapid drop in pressure, causing your bodily fluids to boil and leading to decompression sickness. You would also be exposed to harmful levels of radiation and extreme temperatures, resulting in rapid hypothermia or hyperthermia. Ultimately, you would not survive for long due to the hostile conditions of space.
until your air runs out or forever
as long as you are wearing a spacesuit
As long as you are inside the spacecraft or inside the habitat, or on the Earth, you're probably fine. If you take off your spacesuit in space, you will die within seconds.
Indefinitely. With food water and oxygen Edited: Without gravity the human body would soon loose function of their organs and muscles. Which includes heart, liver, lungs. Only a few months without gravity the human body starts experiencing these effects. NASA has a strict exercise regiment for astronauts to prolong the unwanted effects. With exercise a human can live in a contained area with food, water, and exercise for a few years.
There is currently no specific limit to how long a human can stay in space. Astronauts have spent up to a year on the International Space Station, but long-term effects on the body are still being studied. Extended stays in space can lead to muscle atrophy, bone density loss, and other health concerns.
probably a month.