'Adjust your location quickly' — How China warns residents before rockets crash down from space

China successfully launched satellites to space last week but a shower of rocket debris after the launch crushed buildings in the Sichuan province, captured in a video shared widely on social media.

Before the government launched a Long March 3B rocket from the Xichang Satellite Launch Center on Friday evening, it warned residents with a notice that read “If you see any flying objects falling from the sky, please adjust your location quickly to avoid any harm.”

China conducts many of its orbital launches from Xichang each year. Additionally, the majority of those rockets are the Long March 3B variation, which is comparable in size and power to U.S. rockets such as the SpaceX Falcon 9 or United Launch Alliance Atlas V.

But unlike U.S. launch pads, which are typically located along coastlines, Xichang is deep inland, which means the rocket flies directly over villages in rural China. As these rockets climb, they shed the “boosters” that make up the lower portion of the rocket. While U.S. rocket boosters typically fall back to the ocean, the Chinese rockets launched from Xichang fall over land, threatening local communities.

Social media in China has been awash with photos and videos of fallen rocket pieces after previous launches from Xichang, with multiple reported incidents in the past two years. Last year a booster was even caught on video, falling and exploding near a village after a launch. Officials intend for debris to fall in marked areas of the forest near the launchpad. But there are at least 14 villages in the path of potential debris from Xichang launches, according to a recent evacuation notice obtained by CNBC.

While there have not been any reported injuries or deaths following Friday’s launch, tragedy has struck in the past. In 1996, the first Long March 3B launch veered off course shortly after launch and struck a nearby village, killing at least six people and injuring 57 according to state officials.

The local government distributed evacuation notices to residents a few days ahead of the most recent launch, which warn people to take shelter just before the launch and run away from any falling rocket debris.

“At that time, please cut off your power at home 20 minutes prior and hide at a safe area. If you see any flying objects falling from the sky, please adjust your location quickly to avoid any harm. If you discover any debris, please don’t get close or pick them up because they could be harmful to human bodies due to the chemicals,” a notice obtained by CNBC said.

Here is a translation of the full warning to residents:

China National Space Administration (CNSA) did not immediately respond to CNBC’s request for comment on the video and warning. CNSA is China’s national space agency. The state-owned entity which built and launched the rocket, China Aerospace Science and Technology Corporation, also didn’t respond right away.

The country has been testing a technology called grid fins to help guide the rocket boosters back to Earth more accurately. SpaceX uses grid fins on its rockets to help steer them toward its landing pads. But so far China has only tested grid fins on its Long March 2C and Long March 4B rockets, so the Long March 3B rocket boosters continue to fall back to the ground uncontrolled.