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Jonathan McDowell Profile picture
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7 May, 5 tweets, 1 min read
This one is for the deep nerds, you know who you are. Objects 44983 and 45039 were SOZ debris objects in elliptical 400 x 19000 km orbits until Dec 2020 when the 18SPCS catalog numbers were suddenly reassigned [1/n]
Since Dec 2020 those numbers have referred to two totally different objects, debris objects from the Iridium-Cosmos collision in 700-km-ish circular orbits. So historical TLE analysts should be careful: the 2020 TLEs for those cat numbers should not be mixed with the 2021 TLEs
What happened to those SOZ objects described by those 2020 TLEs? Did they never exist? Were they accidental duplicates of other objects? Did they suddenly evaporate? Who knows... these catalog changes happen without explanation.
In my system I am reassigning those orphan TLEs to new objects A09755 and A09756 in my auxiliary GCAT catalog so they have somewhere slightly less confusing to live.
I now return you to your normal Chinese-rocket-apocalypse coverage.

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More from @planet4589

Jonathan McDowell Profile picture
8 May
The EU SST prediction is narrow enough that we can start to talk about location now!
In particular, none of the orbits within the predicted window cross the northwestern US or the mid Atlantic seaboard. Image
Southern Africa is also out of the target crosshairs Image
In India, Kerala and Tamil Nadu are clear, as are most the northern stages like Uttar Pradesh and Odisha Image
Read 5 tweets
Jonathan McDowell Profile picture
5 May
Chinese media via Reuters: reuters.com/article/space-…

I have some comments:
"likely to fall in international waters" - correct, but you don't know that for sure.
"not worth panicking about" - I completely agree, no reason for panic. BUT
"... could cause damage [is] Western hype" No, I disagree. The last one caused damage!
"China's .. space monitoring network will keep a close watch ... and take measures to avoid damage to passing ships" Eh? What measures? There is absolutely nothing they can do. This is what is known in the trade as a "lie".
Read 5 tweets
Jonathan McDowell Profile picture
29 Apr
Pleaides Neo 3 separation confirmed, congrats to @Arianespace and Airbus. Two more burns at 0251 and 0327 UTC before the remaining payload separations at 0331-0332 UTC
@Arianespace NorSat-3 is an AIS (ship tracking) satellite for the Norsk Romsenter (Norwegian Space Centre) and is a 15 kg Nemo class satellite built by UTIAS-SFL (Toronto). It also carries an instrument to detect navigation radars.
@Arianespace AII-Bravo is a 6U cubesat payload for Aurora Insight (D.C.) to monitor the radio spectrum enviroment, built by AAC SpaceQuest
Read 7 tweets
Jonathan McDowell Profile picture
28 Apr
Very sorry to hear of the death of @AstroMCollins today. Mike Collins (1930-2021) was the pilot of Gemini 10 and the command module pilot of Apollo 11.
@AstroMCollins While his crewmates were on the surface and he orbited above the farside Collins became the first human to have an entire world between him and all other humans.
Collins wrote the first really good astronaut autobiography, Carrying the Fire (which you should read).
Read 8 tweets
Jonathan McDowell Profile picture
26 Mar
Some fun facts about space debris reentries:
(1) A breakup like the one over Seattle happens at about 60 km (~40 miles) up, far above where airplanes fly (more like 10 km).
(2) satellites (including space junk like this rocket stage) orbit the Earth at over 7.5 km/s (17000 mph).
3) We could predict this rocket stage would reenter today. But as of yesterday the TIME at which it would reenter was still uncertain by 5 hours.
Read 5 tweets
Jonathan McDowell Profile picture
25 Mar
The Fregat stage should now have made its circularization burn and the first 4 satellite separations should happen soon
The first 4 sats released were OneWeb 0108, 0174, 0177, 0178. The second four satellites have now been released: 0155, 0163, 0166, 0171.
Satellites 0112, 0115, 0116 and 0158 should have been released at 0444 UTC, while I was distracted by North Korean missile geolocation. Satellites 0151, 0159, 0172 and 0173 will pop out at 0503 UTC, about 10 minutes from now
Read 5 tweets

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