Issue 65

Just a Matter of Time: 6m Near Miss in LEO

27 Jan 2023: LeoLabs reported two pieces of Russian space debris came within ~6m of colliding in orbit. Both uncontrolled objects are in a particularly dangerous LEO altitude (between 950- 1050km). One object is an SL-8 rocket upper stage used to launch a Tsikada navigation satellite in 1986. The other debris is a Parus data relay satell…

27 Jan 2023: LeoLabs reported two pieces of Russian space debris came within ~6m of colliding

in orbit. Both uncontrolled objects are in a particularly dangerous LEO altitude (between 950-

1050km). One object is an SL-8 rocket upper stage used to launch a Tsikada navigation satellite

in 1986. The other debris is a Parus data relay satellite launched by a Kosmos-3M in 1998.

– Two large, defunct objects in LEO narrowly missed each other — an SL-8 rocket body (16511) and Cosmos 2361 (25590) at an altitude of 984km. – Based on LEOLabs radar tracking data, the computed miss distance was 6m with an error margin of a few tens of meters. – Cosmos 2361 has a 17m long gravity gradient boom. – LeoLabs says the incident was very close to being a "worst-case scenario" that could have generated thousands of more pieces of debris in a ripple effect.

– 984km is in the middle of what LEOLabs calls a "bad neighborhood". – This region, 950-1050km, has significant debris-generating potential in LEO due to a mix of breakup events and abandoned derelict objects. – This region hosts ~160 SL-8 rocket bodies along with ~160 payloads deployed over 20 years ago. – There were 1,400 high-Probability of Collision conjunctions involving these rocket bodies between Jun-Sep 2022 alone. – Had the SL-8 rocket body and Cosmos 2361 collided, it likely would've resulted in thousands of new debris fragments that would have persisted for decades.

SL-8 Second Stage

Parus Satellite

Just a Matter of Time: 6m Near Miss in LEO

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