Issue 110

20 Nov: China’s Shijian-17 (SJ-17) (41838) recently crossed 179.9°E longitude and officially drifted into the Western Hemisphere (just barely). The satellite is now at 178.0°W longitude and has rejoined the GEO belt and has stabilized at its new longitude. This is the furthest west (or east depending on how you look at it) since SJ-17 its 2018 encounter with Chinasat 20.

– SJ-17 began its eastward journey 21 months ago, all the way back to late February 2023. At that time the satellite was at 94.7°E (due south of the center of mainland China).

– Over the past year and a half, SJ-17 has significantly changed its altitude (SMA) 6 times, 5 of the 6 maneuvers resulted in decreased altitude which increases eastward drift.

– Most recently (on about 1 Nov 2024), SJ-17 decreased its altitude ~76.2km and stayed below the GEO belt until 14 Nov. During this time it drifted eastward nearly 13° from 169.3°E to 178.0°W. On 14 Nov, SJ-17 increased its altitude 76.2km and stabilized at 178.0°W.

– The nearest operational satellite in this vicinity appears to be Russia’s Yamal-300 (38978), a communications satellite launched in 2012.

SJ-17 Background

– SJ-17, is a technology demonstrator for testing various payloads on-orbit for satellite design improvements. China has publicly stated that SJ-17 is being used for testing a new “green propellant,” composite load carrying structures, solid composite lithium-ion batteries, and various temperature and vibration control systems. It was designed by the National University of Defense Technology. It also hosts a test kit for Global Navigation Satellite System (GNSS) in GEO.

-Per Kristin Burke’s report: “SJ-17 has conducted RPOs with a ChinaSat-5A in 2016 (launched in 1998, manufactured by Lockheed Martin, and moved to graveyard orbit two years later in 2018) and three other Chinese satellites probably experiencing anomalies: ChinaSat-1C in 2018 (launched in 2015 and had been drifting at the time of RPO), a dedicated military satellite ChinaSat-20 also in 2018 (launched in 2003 and had been experiencing anomalies at time of RPO), and ChinaSat-6B in 2020 (launched in 2007 and had experienced a power outage in 2009, but is expected to operate until at least 2022, manufactured by Thales Alenia).”

– When he was the head of USSPACECOM in April 2021, General James Dickinson, warned Congress that robot arms, such as the one attached to the Chinese spacecraft Shijian-17, could have nefarious purposes like attacking satellites.