# Mass calcuations in space

• nuby
In summary, determining the mass of an object in outer space can be done by attaching it to a spring with a known spring constant and measuring simple harmonic motion. This method was used to measure the mass of astronauts on Skylab. Another option is to calculate the mass from the moment of inertia of a body with known geometry. Further information can be found on the NASA website regarding the device used for mass measurements on Skylab.

#### nuby

Mass calculations in space

If an astronaut wanted to determine the mass of an object in outer space (0g), what is the procedure?

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Could you though? I would think you would only be able to calculate the moment of inertia, not the actual mass.

You could attach it to a spring with a known spring constant and use simple harmonic motion.

Kazza_765 said:
Could you though? I would think you would only be able to calculate the moment of inertia, not the actual mass.
One could calculate the mass of a body of known geometry from it's moment of inertia.
Kazza_765 said:
You could attach it to a spring with a known spring constant and use simple harmonic motion.
However, I do think this would be the better option.

Oscillating the inertial mass on a spring was the principle used to measure the mass of astronauts on Skylab.

As I'm new here I can't post urls in my messages yet, but search for "Mass Measurements Aboard Space Station Skylab" with your favourite search engine and you should get a hit from the NASA website which describes the device used to measure the astronauts' mass.

Thanks... a few more posts and I'll have the power to give URLs.

## 1. How is mass calculated in space?

Mass in space is calculated using Newton's Law of Gravitation, which states that the force of gravity between two objects is directly proportional to their masses and inversely proportional to the square of the distance between them. By measuring the gravitational force between two objects, scientists can calculate their masses.

## 2. Do objects have the same mass in space as they do on Earth?

No, objects have the same mass regardless of their location in space. However, their weight may vary due to the differences in gravitational pull on different planets or in different regions of space.

## 3. How is the mass of a planet or star determined?

The mass of a planet or star can be determined by observing the orbital motion of other objects around it. Using Kepler's Laws of Planetary Motion, scientists can calculate the mass of the central object based on the orbital period and distance of the orbiting objects.

## 4. Can mass be created or destroyed in space?

No, according to the Law of Conservation of Mass, mass cannot be created or destroyed, only transformed from one form to another. This applies to all objects in space as well.

## 5. How does the mass of an object affect its motion in space?

The mass of an object affects its motion in space through its inertia, which is the tendency of an object to resist changes in its motion. Objects with larger masses have greater inertia and therefore require more force to accelerate or change direction compared to objects with smaller masses.