Elon Musk’s SpaceX postponed its planned Saturday launch of a U.S. military satellite because of strong winds, marking the fourth scrapped launch in one week, according to Reuters. SpaceX officials said that the company will try launching the U.S. Air Force navigation satellite at 8:51 a.m. eastern time on Sunday. The other launches were scrapped because of weather and technical delays, Reuters reports. Musk’s rocket venture had long been trying to enter the profitable market of military space launches, which has traditionally been dominated by industry giants Boeing Co. and Lockheed. The launch would have been SpaceX’s first national security space mission, the company said. SpaceX filed a lawsuit against the Air Force in 2014 to challenge the military’s decision to award United Rocket Alliance, a partnership between Lockheed and Boeing, a multi-billion, non-compete contract for 36 rocket launches. When the Air Force agreed to allow competition in launch providers, SpaceX dropped its suit in 2015.