NASA is researching the effects of reduced gravity on bone healthy. Why are astronauts losing bone mineral density while in space? Can it be prevented? What are the implications for long duration space flight missions? Explore this challenge of human space flight in this NASA episode of Spark 101. Access the Lesson Plan, Student Worksheets, and Templates associated with this video in the Materials section and on the Educators Resources section of the Spark101 website. For an algebra lesson related to this video, please see the Materials section.