Pressure in space is typically extremely low, close to a perfect vacuum. The vacuum of space is due to the extremely low density of matter in space. The density of matter in the interstellar medium, the space between stars, is typically less than one atom per cubic centimeter. In comparison, the density of air at sea level on Earth is approximately 2.5 x 10^19 molecules per cubic centimeter.

However, it's important to note that even though space is considered a vacuum, it's not completely empty. There are still some particles, such as hydrogen and helium atoms, as well as cosmic dust and radiation, present in space. These particles contribute to a very low level of pressure, known as the interstellar pressure.

The pressure in space can vary depending on the location. For example, the pressure in the solar wind, the stream of charged particles emitted from the Sun, is higher than the pressure in the interstellar medium. The pressure in planetary atmospheres can also vary depending on the composition and temperature of the atmosphere.