The Briefing Room

General Category => Science, Technology and Knowledge => Space => Topic started by: Elderberry on May 10, 2020, 01:35:42 pm

Title: U.S. military tracking unguided re-entry of large Chinese rocket
Post by: Elderberry on May 10, 2020, 01:35:42 pm
Spaceflight Now by Stephen Clark  May 9, 2020

A Chinese rocket measuring around 100 feet long that launched earlier this month will likely plunge back into Earth’s atmosphere some time Monday, becoming the most massive object in decades to fall out of orbit in an uncontrolled manner.

The core stage of China’s Long March 5B rocket is expected to fall back to Earth unguided after nearly a week in orbit. The Long March 5B rocket launched May 5 with a prototype for a next-generation Chinese crew capsule.

As of Saturday, the rocket stage was circling Earth in an elliptical orbit ranging between 94 miles (152 kilometers) and 167 miles (270 kilometers) in altitude, according to U.S. military tracking data. A prediction issued Saturday by the U.S. military, which tracks objects in orbit, forecasts the rocket’s re-entry in a 24-hour period between 2335 GMT (7:35 p.m. EDT) Sunday and 2335 GMT (7:35 p.m. EDT) Monday.

More: https://spaceflightnow.com/2020/05/09/u-s-military-tracking-large-chinese-rocket-reentry/ (https://spaceflightnow.com/2020/05/09/u-s-military-tracking-large-chinese-rocket-reentry/)

(https://mk0spaceflightnoa02a.kinstacdn.com/wp-content/uploads/2020/05/lm5core1.jpg)
File photo of a Long March 5 core stage on a previous mission. Credit: Xinhua

(https://mk0spaceflightnoa02a.kinstacdn.com/wp-content/uploads/2020/05/2020-027C_130L-2.jpg)
This map illustrates some of the possible tracks the Long March 5B rocket body could take on Monday, the expected day of
re-entry. An exact location of the re-entry cannot be predicted with certainty. Credit: Aerospace Corp.
Title: Re: U.S. military tracking unguided re-entry of large Chinese rocket
Post by: Cyber Liberty on May 10, 2020, 06:07:15 pm
That's a rather eccentric orbit.  I'd like to know on that map where it's only 94 miles away from the Earth.  That's where we'll see the most degradation in the orbit, being well into the atmosphere.
Title: Re: U.S. military tracking unguided re-entry of large Chinese rocket
Post by: Joe Wooten on May 11, 2020, 02:21:43 am
That's a rather eccentric orbit.  I'd like to know on that map where it's only 94 miles away from the Earth.  That's where we'll see the most degradation in the orbit, being well into the atmosphere.

When Gus Grissom and John Young flew Gemini 3 in a 3 orbit flight in 1965, they did an exhaustive test flight of the capsule's ability to change orbits going from a circular orbit at roughly 122 by 175 km to an almost circular orbit in the second orbit, then again to an elliptical orbit with a perigee at 72 km (~40 miles) for the third orbit. This would ensure re-entry in case the retro rockets failed.