Mark Vande Hei, a retired Army colonel, trains on the advanced resistive exercise device, which astronauts use to stop muscle loss while being weightless in space, at Johnson Space Center in Houston, March 1, 2017. Astronauts can simulate free-weight exercises in normal gravity by using the device's adjustable resistance piston-driven vacuum cylinders to get a load of up to 600 pounds. DoD photo by Sean Kimmons