Chinese space lab Tiangong-1 (or “heavenly palace”) is set to fall back to Earth some time at the end of March or beginning of April. The catch: It’s unclear where it will fall. The 19,000-pound space lab — China’s precursor to a space station, according to NPR — was decommissioned and de-orbited in 2016, after being in use for nearly five years, Popular Mechanics reported.