in the Shuttle program, plus unexpectedly high solar activity, made this impossible. On February 7, 1991, the Soviet Salyut 7 space station (), with the Kosmos 1686 module () attached, reentered and scattered debris over the town of Capitán Bermúdez, Argentina. The station had been boosted to a higher orbit in August 1986 in an attempt to keep it up until 1994, but in a scenario similar to Skylab, the planned Buran shuttle was cancelled and high solar activity caused it to come down sooner than expected. On September 7, 2011, NASA announced the impending uncontrolled reentry of the Upper Atmosphere Research Satellite () and noted that there was a small risk to the public. The decommissioned satellite reentered the atmosphere on September 24, 2011, and some pieces are presumed to have crashed into the South Pacific Ocean over a debris field long. On April 1, 2018, the Chinese Tiangong-1 space station () reentered over the Pacific Ocean, halfway between Australia and South America. The China Manned Space Engineering Office had intended to control the reentry, but lost telemetry and control in March 2017. On May 11, 2020, the core stage of Chinese Long March 5B (COSPAR ID 2020-027C) weighing roughly ) made an uncontrolled reentry over the Atlantic Ocean, near West African coast. Few pieces of rocket debris reportedly survived reentry and fell over at least two villages in Ivory Coast. On May 8, 2021, the core stage of Chinese Long March 5B (COSPAR ID 2021-0035B) weighing ) made an uncontrolled reentry, just west of the Maldives in the Indian Ocean (approximately 72.47°E longitude and 2.65°N latitude). Witnesses reported rocket debris as far away as the Arabian peninsula. It is expected that the Cruise Mass Balance Devices (CMBDs) from the Mars 2020 mission, which are ejected prior to the spacecraft entering the atmosphere, will survive re-entry and impact the surface on Thursday 18 February 2021. The CMBDs are 77 kg tungsten blocks used to adjust the spacecraft's trajectory prior to entry. The Science Team of another NASA mission, InSight, announced in early 2021 that they would attempt to detect the seismic waves from this impact event. In 2022 it was confirmed that space debris that had landed in New South Wales Australia were from the unpressurised trunk section of the SpaceX Crew-1 Crew Dragon spacecraft that had launched to the International Space Station in November 2020. Deorbit disposal Salyut