Over 10% chance of a collision Thursday evening (US time) between two defunct satellites (2800 kg combined mass) 991 km above Earth

 

The satellites are:

 

• NORAD catalog number 19826 = Cosmos 2004 (Russian payload), launched 1989

• NORAD catalog number 36123 = CZ-4C R/B (Chinese rocket body) from launch of YAOGAN 8 satellite, launched 2009

 

If the satellites crash, the crash itself will be visible from southern Argentina, and the debris cloud would be visible afterwards from other parts of the world.

 

Report from Leo Labs:

 

https://twitter.com/LeoLabs_Space/status/1316147305125490694

 

LeoLabs, Inc.

@LeoLabs_Space

 

1/ This event continues to be very high risk and will likely stay this way through the time of closest approach. Our system generates new conjunction reports 6-8x per day on this event with new observation data each time.

 

2/ Current risk metrics from our most recent CDMs:

Miss distance: 12 meters (+18/-12 meters)

Probability of Collision: >10%, scaled to account for large object sizes

Relative velocity: 14.7 km/s

 

3/ Shortly after TCA, we will have a direct pass of CZ-4C R/B over our Kiwi Space Radar in New Zealand. We have scheduled a search mode scan during this time to ensure we only see two objects as expected and hopefully confirm that no new debris is detected.

 

Earlier:

 

https://twitter.com/LeoLabs_Space/status/1316147305125490694

 

We are monitoring a very high risk conjunction between two large defunct objects in LEO. Multiple data points show miss distance <25m and Pc between 1% and 20%. Combined mass of both objects is ~2,800kg.

 

Object 1: 19826

Object 2: 36123

TCA: Oct 16 00:56UTC

Event altitude: 991km

 

Prediction map from HeavenSat attached here (star map from a possible viewing location in Argentina)

 

In the Seesat-L satellite forum, Bjorn Gimle writes that the collision would be visible for anyone at the southern tip of Argentina. At the altitude of the satellites the sun is shining, but it's night on the ground. If a collision happens (far from certain) it would be very spectacular, even to a casual observer without binoculars.

 

http://www.satobs.org/seesat/Oct-2020/0061.html

 

If there is a collision, there may be opportunities worldwide for observers to watch the debris cloud (the debris from each satellite will approximately follow the same track around Earth, but as an expanding cloud of fine debris, which would catch and reflect sunlight – somewhat akin to seeing a comet's tail.) I have not mapped out viewing opportunities for a debris cloud (what other locations in the world would have an opportunity to see it).

 

Orbital data on the Chinese rocket body (NORAD two-line element format)

 

1 36123U 09072C 20287.49580561 -.00000051 +00000-0 -33925-5 0 9995

2 36123 100.3627 198.5798 0156431 242.9039 293.1887 13.46117623532127

 

Epoch (UTC): 13 October 2020 11:53:57

Eccentricity: 0.0156431

inclination: 100.3627 degrees

perigee height: 970 km

apogee height: 1203 km

right ascension of ascending node: 198.5798 degrees

argument of perigee: 242.9039 degrees

revolutions per day: 13.46117623

mean anomaly at epoch: 293.1887 degrees

orbit number at epoch: 53212

 

Orbital data on the Russian payload (NORAD two-line element format)

 

1 19826U 89017A 20287.50474159 +.00000020 +00000-0 +57292-5 0 9997

2 19826 082.9566 009.9157 0028993 246.7601 123.6618 13.72296026584419

 

Epoch (UTC): 13 October 2020 12:06:49

Eccentricity: 0.0028993

inclination: 82.9566 degrees

perigee height: 970 km

apogee height: 1013 km

right ascension of ascending node: 9.9157 degrees

argument of perigee: 246.7601 degrees

revolutions per day: 13.72296026

mean anomaly at epoch: 123.6618 degrees

orbit number at epoch: 58441