In our quest to explore the Moon and Mars, our journey will require both humans and hardware to function in a variety of gravity environments. The Earth, Moon, Mars and outer space all differ in their gravitational characteristics. We are all familiar with the force of gravity here on Earth. Scientists refer to this as one earth gravity, or 1g. Since the moon has less mass than the Earth, it has a smaller gravitational effect. The gravity on the Moon is only one sixth that of Earth, or 0.17g. Even though humans have never set foot on Mars, we know from remote experiments that the gravitational force on Mars is equivalent to about 38% of Earth’s gravity, or 0.38g.

How much would you weigh on the Moon and Mars? See here.

To get to either one of these destinations, astronauts will need to travel through space, from a few days to get to the Moon to six months to get to Mars. During this time, they will experience the “microgravity” of outer space, which is very close to 0g. The freefall you experience on many amusement park rides gives a brief feel for the environment the astronauts will be living in during this time. Research is currently being performed on the International Space Station which will enable humans to safely live and work in this environment. Research is also being done on the ground in drop towers, such as the 2.2-Second Drop Tower at NASA Glenn Research Center which provides 2.2 seconds of freefall, and on aircraft which fly a parabolic trajectory to produce approximately 25 seconds of freefall. Video of research performed on a DC-9 aircraft can be found here.