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| click diagram to enlarge |
In my previous post, I discussed 2021-017BN, the Falcon 9 upper stage from the March 4 Starlink launch that should have been deorbitted after 1.5 revolutions on March 4th, but didn't.
It is still on orbit. At the moment of writing, 23 March 2021 at 11:00 UT, it is in a 217 x 200 km orbit according to the latest available elements from CSpOC, and it will stay on orbit for a couple of days to come. But the end is near: the orbital altitude of the rocket stage is quickly decaying, as can be seen in the diagram below:
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| click diagram to enlarge |
My current reentry prediction (see diagram in top of post and table below) is that it will come down in the early hours of March 26 (2021). My prediction, based on modelling in GMAT R2020a using the MSISE90 model atmosphere, appears to be well in line with the TIP from CSpOC so far.
[UPDATE: my final post-cast predicted reentry at 26 Mar 04:34 UT, which is some 35 minutes too late. It is based on a 2/3rd maximum drag surface value. Interstingly, using the maximum drag surface leads to a reenrty at 3:56 Ut, within minutes f the actual time]
Revisit this post for prediction updates in the coming days.
orbit epoch pred. date reentry time (UT)
21081.600725 26 Mar 2021 02:33 +- 16.8 hr
21081.922054 26 mar 2021 03:36 +- 15.5 hr
21082.113317 26 Mar 2021 03:59 +- 14.7 hr
21082.216601 26 Mar 2021 03:40 +- 14.1 hr
21082.278149 26 Mar 2021 03:43 +- 13.8 hr
21082.462749 26 Mar 2021 05:29 +- 13.3 hr
21082.585776 26 Mar 2021 05:29 +- 12.7 hr
21082.708770 26 Mar 2021 05:37 +- 12.1 hr
21082.954651 26 Mar 2021 06:13 +- 11.1 hr
21083.138960 26 Mar 2021 05:03 +- 9.9 hr
21083.261785 26 Mar 2021 05:15 +- 9.4 hr
21083.296296 26 Mar 2021 05:20 +- 9.2 hr
21083.507296 26 Mar 2021 05:28 +- 8.3 hr
21083.875164 26 Mar 2021 05:26 +- 6.5 hr
21084.120127 26 Mar 2021 05:59 +- 5.4 hr
21084.181325 26 Mar 2021 05:20 +- 5.0 hr
21084.486963 26 Mar 2021 05:00 +- 3.5 hr
21084.548018 26 Mar 2021 03:19 +- 2.8 hr
21084.974688 26 Mar 2021 04:46 +- 1.1 hr * post-cast
21085.095602 26 Mar 2021 04:34 +- 0.5 hr * final post-cast
UPDATE 26 March 2021 12:30 UT:
The reentry happened last night, over North America, and was widely seen from the US States Washington and Oregon, near 4:00 UT (March 26 UT: that is 9 pm on March 25 local time for that area).
CSpOC's final TIP places the reentry at 03:58 +- 1 min UT. This time matches the reports from Washington and Oregon well, and based on the last orbit it would indeed place the rocket stage near the NW United States coast.
The listed geographic position in the TIP, 24.5 N, 151 W, does however not match well (it is further down the track, near Hawaii, corresponding to the Falcon 9 position about 6 minutes prior to the observed reentry). We have noted such discrepancies more often in recent TIP messages. In this case, I half suspect the position was that given by their reentry model, and they forgot to update it when the SBIRS detection of the actual reentry fireball came in.
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| click map to enlarge |
My own final "post-cast" places reentry some 35 minutes after the actual reentry.
Here are some of the reentry sightings as reported on Twitter:
DID YOU SEE THIS? I have never in my life seen something so incredible. I am in awe. Just happened over Portland about 10 minutes ago. #LiveOnK2 pic.twitter.com/L9wLEXBrcW
— Genevieve Reaume (@GenevieveReaume) March 26, 2021
uuuuuhhhh holy shit we just saw this meteor shower across the sky?!?! #pdx pic.twitter.com/umaE0joW7J
— lynseylou (@lynseylou) March 26, 2021
UPDATE 2 April 2021 23:00 UT:
Debris has been recovered from this reentry. In Grant Country, Washington, a Composite Overwrapped Pressure Vessel (COPV) was found on farmland.
SpaceX recovered a Composite-Overwrapped Pressure Vessel from last week’s Falcon 9 re-entry. It was found on private property in southwest Grant County this week. Media and treasure hunters: we are not disclosing specifics. The property owner simply wants to be left alone. pic.twitter.com/dEIQAotItY
— Grant County Sheriff (@GrantCoSheriff) April 2, 2021
6 comments:
thanks! excellent work as always.
I wonder why this is not covered by other media? An uncontrolled reentry with some debris to be likely to reach the ground would usually catch their attention. Or is it clear that no debris will survive the reentry?
I'm collecting widespread consistent reports of a rumble heard simo with the overflight -- physically impossible for acoustic sound generated 60+ km high. Are we getting indications of a powerful electrophonic ['meteor sound'] event? The reports come from rural areas with very low ambient background noise.
Here's a story I did on that phenomenon during the much more powerful Chelyabinsk bolide:
http://www.astronomy.com/magazine/2013/04/the-whispering-bolide
My reply email is jamesEoberg@comcast.net, not the 'gmail' address.
Hi Jim,
Interesting! I once heard electrophonic sound from a meteor, so I know it exists.
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