As reported by engadget,
Taking off from Boca Chica, Texas, SpaceX plans to launch its 160-foot tall prototype Starship spacecraft to a height of 12.5km (41,000 feet) above the surface and safely return to its launch pad. The company has set a launch window beginning at 5:30pm ET and you can see it live via SpaceX’s YouTube channel.
Plans have been in place to conduct this test for several months. Originally slated to fly as high as 60,000 feet, that mark was reduced to 50,000 feet in September and has since been lowered again. However, following a successful static engine test in late November, SpaceX CEO Elon Musk announced via Twitter that the company was pressing ahead with the high altitude test and would conduct it “imminently.” Turns out that meant today.