Friday 15 September 2023

The upcoming (?) reentry of Kwangmyŏngsŏng 3-2 (KMS 3-2), North Korea's last remaining satellite

KMS 3-2 (image: KCNA)

Somewhere this week, North Korea's last remaining - albeit probably not functional - satellite on orbit, Kwangmyŏngsŏng 3-2 (KMS 3-2, 2012-072A), will reenter (or has it already? See later...).

Kwangmyŏngsŏng 3-2 was launched on 12 December 2012 and was North Korea's first succesful satellite launch. Following in the footsteps of a later launch, KMS 4 from 2016 which reentered earlier this year on 30 June 2023, it is now set to have an uncontrolled reentry. 

With this, North Korea will lose the last satellite they have on orbit (the UNHA-3 upper stage of this launch is still on orbit).

It is not clear whether KMS 3-2, said to be a remote sensing satellite to monitor crops and weather, was ever functional. To my knowledge, no independent reception of signals from the payload has ever been reported.

Unfortunately, orbital updates for KMS 3-2 stopped to appear in the CSpOC catalogue after September 12. The last available orbit has epoch 12 Sept 2023 15:20:30 UTC. My reentry forecast based on that orbit was 16 Sept 2023 18:00 UTC ± 20 hrs.


click diagram to enlarge


A TIP was not issued (it wasn't for KMS-4 either at the time), but a reentry notice was suddenly added to the KMS 3-2 entry in the CSpOC SATCAT on Sept 15, stating 13 September 2023 as the reentry date.

I think that date is not correct, and merely an 'administrative decay'  - meaning they either don't really know, or are not willing to share, when it really reentered. 

The last known orbit from September 12 is a 226 x 235 km orbit and even using extremely high values for solar activity (higher than they in reality were) I can't get it to reenter earlier than Sept 15-16 in my GMAT model, nor in SatEvo. I simply don't see it coming down from that altitude within a day, unless something drastic happened (e.g. a structural disintegration of the satellite before the actual reentry). For reference, it took KMS 4 some four-and-a-half days to come down from that altitude and reenter in June.


click diagram to enlarge


So it looks like either CSpOC lost the object and doesn't really know, or they do not want to to share the last whereabouts of KMS 3-2 (e.g. from a notion that this would help the North Koreans in some way).

Meanwhile, after two failed launch attempts the past months using a new carrier rocket, North Korea said it will attempt to loft a new satellite into orbit in October.

I recently talked to the website North Korea News about the upcoming KMS 3-2 reentry, which you can read here.

No comments: