On Monday, a Long March 4B rocket was launched from China’s Taiyuan Satellite Launch Center, which carried a remote-sensing satellite. This 50-year-old spaceport is located about 500 km southwest of Beijing in north-central China.
As often happens with the first phase of Chinese rockets being launched from the inland Taiyuan facility, the spent Long March 4B booster fell from the drift of the spaceport. In this case, it landed near a school, creating a huge cloud of poisonous gas.
Unlike most of the world’s spacecraft, many of China’s launch sites are located inland locations instead of water to avoid such threats. For security purposes, China built its three large launch centers off the water amid tensions with the US and the Soviet Union during the Cold War.
Some impressive footage from today’s Long March 4B first stage return.
ℹ: https: //t.co/9oRPoR0ZdF pic.twitter.com/SEl7t1u5xJ
– LaunchStuff (@LaunchStuff) September 7, 2020
In recent years, China has started experimenting with grid fins to bring its rockets back to Earth and eventually potential land boosters like SpaceX do with their Falcon 9 rockets. However the project is more inspired by master reuse technology than protecting its population, as China has been launching from Taiyuan since 1968 with little regard for nearby residents.
The problem of dropping the rocket into the first phase in the surrounding countryside is that China continues to use toxic hydrogenated fuel for its first stages. The hydrogen atom, which is two nitrogenous bonds bound together by hydrogen atoms, is an efficient, adorable fuel. But it is also highly corrosive and toxic.
When a Crew Dragon spacecraft exploded during a test in April 2019, it produced large clouds of toxic orange gas that can be seen for miles along the Florida coasts. These red clouds were due to nitrogen tetraxide, the oxidizer that combusts with hydrangein fuel. This spacecraft — and many others in the past — used adorable propellants for space missions. NASA is working to find “green” propellants, which will reduce the need to use hydrazine for in-space operation as well.
This is a different story for Rocket. The use of hydrazine as fuel for launch vehicles has been phased out for most of the world. The last major US rocket to use hydrangeaine was the Delta II rocket of the United Launch Alliance, which used toxic fuel in its second phase. This rocket was retired in 2018. Russia’s workhorse proton rocket uses hydrangeaine for its first and second stages.
Yet most of China’s launch fleet is powered by hydrogen fuel and nitrogen tetroxide oxidizers. This includes its human-rated Long March 2F rocket as well as the widely used Long March 4 family. All of these rockets, with their toxic first stages, launch on land and many events have occurred over the years. These fuels are cheap and relatively easy to use, and it was natural for China to use them when these boosters developed in the 1980s and 1990s. But their use continues unabated today.
China is slowly changing. Its new family of large rockets, the Long March 5 fleet, is filled with liquid oxygen and kerosene like SpaceX’s Falcon 9 rocket. Paradoxically, however, Long March 5 rockets are typically launched over the sea from the Wenchang spacecraft launch site.