![Request for Information – Potential [Placeholder for Prize]](https://assets.science.nasa.gov/dynamicimage/assets/science/psd/solar/2023/09/s/solarsystem_0.jpg?w=1024)
APOD
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
To Fly Free in Space
Explanation: What would it be like to fly free in space? At about 100 meters from the cargo bay of the space shuttle Challenger , Bruce McCandless II was living the dream -- floating farther out than anyone had ever been before. Guided by a Manned Maneuvering Unit (MMU), astronaut McCandless, pictured , was floating free in space. McCandless and fellow NASA astronaut Robert Stewart were the first to experience such an “un tether ed space walk ” during Space Shuttle mission 41-B in 1984 . The MMU worked by shooting jets of nitrogen and was used to help deploy and retrieve satellites . With a mass over 140 kilograms, an MMU is heavy on Earth , but, like everything, is weightless when drifting in orbit. The MMU was replaced with the SAFER backpack propulsion unit.
Memorial: Astronaut Bruce McCandless II Dies at 80
| Date | December 31, 2017 |
|---|---|
| Credit | Image Credit: STS-41B , NASA |
| Authors & editors: | Robert Nemiroff (MTU) & Jerry Bonnell (UMCP) |
| A service of: |
ASD at NASA / GSFC, NASA Science Activation & Michigan Tech. U. |