Tin hats everybody! Incoming Chinese rocket body...
 

Blimey...

Daily Telegraph

Tianhe Space Station

Stay Angry...
 

The Angry Astronaut was getting all hot under the collar about this the other day.

I know journalists are selected for their writing skills rather than their scientific knowledge, but the author of this headline clearly didn't even read the article...

Heads-up - uncontrolled reentry of large rocket booster projected May 8-10
 

Pilot organizations circulating bulletins alerting aviators to pending imminent uncontrolled re-entry of large rocket booster:

21sab10-long-march-re-entry.pdf (ifalpa.org)

This is crazy , launching rockets in space and let booster fall random on earth ...

It would be ironic if it hit Beijing:)

Not 'irony' - as much as 'KARMA'.....

That rather large rectangular building on the LHS of 'T' Square would be 'luvly'....

Why does the USA offer to track this thing and warn us exactly when on 8th May it will come cartwheeling down?

Is it not the responsibility of the government of China to do this? Or are they just being irresponsible?

Nick 1

Random re-entries have been going on since 1957 but most final stages of boosters are small enough for them/their components to not generally survive re-entry.

Problem here is this a seriously big piece of hardware and custom and practice is entry should have been controlled and targeted for a remote area.

https://spacenews.com/huge-rocket-lo...tation-launch/

FWIW the US has had a system in place for years that tracks objects in orbit 24/7 and if relevant to the object produces reentry predictions, so why wouldn't they continue to do so?

https://en.wikipedia.org/wiki/Space_...racking_System

Nobody can tell when exactly it will re-enter, certainly not at this stage there are so many variable involved in the decay process that generally it's more of case of " we're now fairly certain it'll come down in the next hour...oh looks like it's gone", or: more accurately:

"Based on 15 well-monitored IADC re-entry prediction campaigns since 1998, with well-established, observed re-entry times and locations, ESA’s predictions were found to be within ±6% of the remaining orbital lifetime for about 50% of all cases, within ±10% for about 75%, and outside ±20% for about 5% of all forecasts. The latter figure supports ESA’s a priori assumption that a reentry time window of ±20% is a good representation of agregate error sources, leading to a ±2σ = 94.4% confidence interval."

Bearing in mind these things are moving at about 5miles per second even a 1 minute error in entry time means the entry point prediction is out by 300 miles..

Maths stuff about decay in this paper.

Better than nuclear battery powered radar satellite launch failures.

More China bashing?

Does no one remember Skylab or Mir?

No, we are just saying that China is 20 to 40 years behind with their space program :p

Certainly does seem to be a case, putting it politely, of not caring a jot about modern day custom and practise/guidelines regarding disposing :bored: of items of more than ten tonnes.

Practically there are like 20 zenit upper stages waiting to reenter or similar? So just one more doesn't concern me.
Have any airborne aircraft ever been hit by satellite debris or space junk?

The sources I can find seem to give an empty mass for the typical zenit upper stages such as the Blok D of just over two tonnes..

OTOH the Chinese launcher seems to have delivered it's whole darned core stage into orbit, and that's being estimated as having a mass of just over twenty tonnes....hence the concern being expressed in some quarters;..

I'm just north of 41.5 degrees north so I guess I can be a bit relaxed about this...and no idea of any aircraft have ever been hit.

https://aerospace.org/reentries/cz-5...-body-id-48275

Mir was intentionally de-orbited over a mostly unpopulated area using the reaction control system that was installed for that purpose. It hit reasonably close to the pre-planned and pre-announced impact point.

Skylab was intended to be re-boosted during the Skylab V mission, which was cancelled for budgetary reasons as the Shuttle was coming online soon and could do the mission cheaper. Then due to Shuttle program delays the Shuttle was not available to re-boost the station, therefore it re-entered uncontrolled. But that was not the baseline plan, it was a failure of program management and contingency planning.

Uncontrolled de-orbit was the baseline plan for the Long March 5B. And it was launched in 2021, not in 1973. What was once acceptable is now unacceptable, in rocketry and many other fields. We've upped our standards, so up yours.

Just getting this out of the way first: I opened this thread strictly based on the IFALPA (and ALPA) deeming the situation serious enough to be the subject of the warnings or advisories they issued -- no anti-China sentiment or bias motivated it.

Second, I've acquired some at least modest familiarity with academic and related literature on space debris, congestion of the space domain, and the application of conventional thinking to overall, or generalized, problems of safety of space operations. I am not completely certain of this answer, but if significantly large pieces of space debris ever had collided, upon re-entry, with a civil aircraft anywhere, such an accident would -- without question -- feature prominently in the referenced literature. I know, absence of evidence is not evidence of absence, so FWIW. (For comparison, references to the Chinese ASAT test which created thousands of pieces of debris in 2007 are almost a prerequisite in discussions, slide decks, academic papers, and much else, on space debris problems.... the inference being that if a collision of debris with an aircraft ever had occurred, logically it would have garnered similar prominence, in all likelihood.)

Last, it's clear that expertise, virtuosity in performance, and even real pioneering achievements in space technology are continuing to make news. Some would argue that latecomers to space technology do more than just "stand on the shoulders of giants" who preceded them - such latecomers sometimes bypass the attention given to safety, quality assurance, and implicit norms of responsible behavior in space. Some argue that the U.S. is at fault, because it has opposed efforts by other countries to set in place formal rules or norms, or items like a proposed Code of Conduct. Since this is one of my professional areas of study I could go on a lot more....but a prior post said it better than I could: yes Skylab tumbled out of orbit, let's see, that was before Wright Field on Mars, wasn't it?

Just curiosity - did the SpaceX Starlink booster de-orbit burn failure make a splash here last month when eventually created a light show in the Seattle skies back in March? Incidentally, I am posting this using Starlink. Does the Chinese announcement state whether this booster de-orbit creating a possible problem was due to intentionally having no way to do a controlled de-orbit or was it like the SpaceX booster that had a plan but the plan, successful so many times, failed this time. Trying to weed out the China bashing from the oops, sorry about that, didn't mean for my engine nacelle to fall on a soccer match.

NWA SLF

According to the ALPA Safety Bulletin --

Regarding the current situation: "While the launch was successful, the booster stage of the launching Long March 5B rocket was designed for an “uncontrolled” re-entry, and therefore the exact time and location of its return is unknown." (emphasis added)

Regarding the Starlink rocket in the Seattle area: "The most recent uncontrolled re-entry of a rocket was on March 26, 2021, when part of a SpaceX Falcon9 launch re-entered at night over the Pacific Northwest. Debris, including several 200lb pressure tanks, survived re-entry and struck the ground."

Several news outlets have quoted - in both incidents - the professor who is widely regarded as the most knowledgeable and authoritative person on stuff in orbit (a Harvard astrophysics prof). I'm quoting, though, just the ALPA bulletin, inasmuch as this isn't an astrophysics forum (which I wouldn't understand anyway), and whereas the ALPA information was issued over the names of three ALPA officials with relevant subject matter areas of responsibility. (What might or might not have been stated in any publicly available English versions of announcements by PRC or its agencies, I don't know.)