HOUSTON/AUSTIN, Texas — Standing at 6 feet 2 inches (188 cm) tall and weighing 300 pounds (136 kg), Nasa's humanoid robot Valkyrie is an imposing figure. Valkyrie, named after a female figure in Norse mythology and being tested at the Johnson Space Center in Houston, Texas, is designed to operate in "degraded or damaged human-engineered environments," like areas hit by...