Chinas Effort to Launch Starlink Rival Accidentally Creates Orbital Debris Field
pcmag.com
pcmag.com
https://xcancel.com/LeoLabs_Space/status/1821674989021450648
> While Russia and the U.S. have improved their “rocket body abandonment behavior” over the last 20 years, the relative contribution by other countries has grown by a factor of five and China by 50x.
https://amostech.com/TechnicalPapers/2023/Poster/McKnight.pd... page 12
> China has contributed as much mass of abandoned rocket bodies in the last 20 years as Russia, US, and Rest of World combined.
> Over the last 20 years, China has abandoned nearly four times the rocket body mass in LEO compared to the US.
> The average rocket body mass for China on-orbit in LEO is over 2,700 kg while the US is less than 1,000 kg and Russia is less than 1,800 kg. These larger individual masses pose a greater fragment production level if they are involved in a catastrophic collision
Not good stewards.
> Prior to 2003, Russia and the United States were responsible for 97% of the mass of rocket bodies abandoned in low Earth orbit (LEO). Since 2003, China and the Rest of the World are responsible for 68% of the rocket body mass abandoned in LEO. As a matter of fact, these trends over the last 20 years have resulted in China and the US now having roughly the same amount of rocket body mass in LEO. Russia is still responsible for half of the rocket body mass in LEO, down from ¾ of the total mass in LEO as of 2003. The rate that China is leaving abandoned rocket bodies in orbit reverses the improved behavior of US and Russia and results in a continual accumulation of objects that will be especially prolific in creating fragments if involved in a collision.
So if I read it right, in absolute terms Russia still has about 50%, and US and China each about 25%, of the LEO abandoned rocket body mass.
What's the difference?
No. China's debris are in orbit and will remain there for "decades" [1]. This is because its rocket exploded.
The errant Falcon 9 had engine trouble but retained structural integrity [2]. That allowed SpaceX to "make contact with the satellites in order to send early burn commands" so that they "re-enter Earth’s atmosphere," thereby no longer posing "a threat to other satellites in orbit or to public safety."
[1] https://x.com/US_SpaceCom/status/1821615199230816555
[2] https://www.spacex.com/launches/mission/?missionId=sl-9-3
This launch from China inserted the 18 satellites directly into a 500 mile orbit, presumably because they didn't want to fuss with boosting.
This sounds partly a result of their engines. Low orbits require more precision. Liquid-fuelled engines are good at that. The Long March 6A is solid fuelled.
Does Long March 6A's first stage not burn out, past no return, higher than Falcon 9?
For a solid-fuel rocket, burnout altitude almost defines payload altitude. (Long March 6A's liquid-fuelled second stage adjusts for that.) That isn't so for a throttlable engine. Given a solid-fuelled first stage, a competent engineer would add a margin of safety to the energy budget.