地表に再び宇宙機器落ちる、日本の偵察衛星 [VOR]

大気圏で燃焼しなかった日本の宇宙機器IGS-03の破片が12日朝（モスクワ時）、太平洋のロシア領海境界付近（カナダ、ヴィクトリア西沖1500km）に落下する見込みだ。

■IGS 4B Re-Entry [SPACEFLIGHT101]

After ceasing operations in 2010, IGS 4B has started a slow drop toward Earth’s atmosphere as its could no longer maintain its orbit using its propulsion system. Even at high altitudes of 500 Kilometers, drag within Earth’s uppermost atmosphere slows spacecraft down and causes a loss of altitude.

Initially, at higher altitudes, drag levels were low and only caused the satellite to lose a few meters per day, but as the satellites entered more dense regions of the atmosphere, drag increased significantly, speeding up the orbital decay. In May 2012, IGS 4B was found in a 445-Kilometer orbit. By July 2013, the satellite had dropped to 380 Kilometers.

The exact orbit of IGS 4B was not being disclosed to the public, but notifications issued by USSTRATCOM allowed to keep up with current Entry predictions. With the satellite in a polar orbit, re-entry could have occurred over virtually any point on Earth.

IGS-03って何だっけ？と思ったら光学3号機実証衛星のことだったようです。先日機能を停止した光学2号機とは別でした。落下地点は南極近海だそうです。