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Chinas Effort to Launch Starlink Rival Accidentally Creates Orbital Debris Field
- ijidak 2y agoDidn't SpaceX just lose a rocket in similar fashion? What's the difference?
- deleted 2y ago[deleted]
- JumpCrisscross 2y ago> Didn't SpaceX just lose a rocket in similar fashion? 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 https://x.com/US_SpaceCom/status/1821615199230816555 [2] https://www.spacex.com/launches/mission/?missionId=sl-9-3 https://www.spacex.com/launches/mission/?missionId=sl-9-3
- ortusdux 2y agoA key element are the altitudes. SpaceX, out of an abundance of caution, inserts their starlink satellites low enough that any non-functional units or debris will deorbit in a matter of months. If they pass testing, they self-boost to their operational heights of 350 miles or so. At this height they still need to occasionally re-boost themselves. This launch from China inserted the 18 satellites directly into a 500 mile orbit, presumably because they didn't want to fuss with boosting.
- JumpCrisscross 2y agoDid not know. Thank you. 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.
- wmf 2y agoThe Long March 6A second stage that failed here is liquid-fueled.
- JumpCrisscross 2y agoFirst stage sets the gross orbital parameters. You overshoot with solid.
- wmf 2y agoI've seen no evidence that there was any overshoot here. It sounds like the satellites were inserted into the desired orbit and then the second stage broke up.
- JumpCrisscross 2y ago> no evidence that there was any overshoot here. It sounds like the satellites were inserted into the desired orbit and then the second stage broke up 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.
- wumeow 2y agoFrom the linked twitter thread https://xcancel.com/LeoLabs_Space/status/1821674989021450648 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.pdf 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.
- deleted 2y ago[deleted]
- aragonite 2y agoI was curious why those tweets only compared rate of contribution. From the PDF source: > 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.
- wumeow 2y agoYes, China has put the same amount of junk in space in 20 years that the US did in 60, and it isn't slowing down.
- ortusdux 2y agoThis looks to be a better article: https://www.space.com/china-megaconstellation-launch-space-junk https://www.space.com/china-megaconstellation-launch-space-j...
- simonblack 2y agoStarlink IS an orbital debris field.
- JumpCrisscross 2y agoNo. Beyond it being functional, it’s a fleet of controlled, responsive spacecraft. We could command Starlink to deörbit today. We cannot do that with space junk.
- simonblack 2y agoJust ask your local friendly astronomer what he thinks about Starlink.
- JumpCrisscross 2y agoWhy? That’s like asking a psychiatrist about brain surgery. Better than nothing. But far from definitive.
- simonblack 2y agohttps://www.astronomy.com/science/starlink-satellites-disrupt-cosmic-studies/ https://www.astronomy.com/science/starlink-satellites-disrup...