Quiet solar activity has once again pushed back the re-entry time for a China’s falling space station, Tiangong-1, according to the European Space Agency (ESA) and U.S.-based analysis group Aerospace Corp.
The doomed Tiangong-1 is now expected to fall to Earth around 7:25 p.m. EDT (2325 GMT) on Sunday (April 1), with a window that could stretch into early Monday, officials with ESA’s Space Debris Office said in an update this morning (March 31). As of 5 p.m. EDT today, Aerospace Corp., which is also tracking Tiangong-1, predicts Tiangong-1 will crash at 7:53 p.m. EDT (2353 GMT) Sunday, give or take 7 hours. [Track Tiangong-1! Use This Satellite Tracker]
Current predictions for Tiangong-1 show that the station may fall somewhere around Africa, although that area remains highly uncertain. Even a change in time of a minute will alter the predicted debris track by hundreds of miles, cautioned Aerospace Corp. Not only that, Tiangong-1’s re-entry time is becoming more delayed and the station may actually enter on April 2, depending on the sun’s activity and the station’s tumble.
“The predictions are getting farther and farther into the future,” Andrew Abraham, a senior member of the technical staff at Aerospace Corp, told Space.com in an interview today. “We’re going to keep it updated basically as frequently as we get the data, which varies. The sensors aren’t evenly distributed across the globe. Sometimes we get more data, and sometimes periods where there’s not as much data.”
Most of the United States appeared to be in the clear at that time, except for one orbital track that moves over California northeast towards Texas. Again, Abraham cautioned, this information is subject to change as predictions are updated.
The time for Tiangong-1’s uncontrolled descent remains highly uncertain, in large part due to how quiet the sun has been. If the sun is active, its energy pushes more strongly against Earth’s atmosphere. The atmosphere then balloons and becomes denser at higher altitudes. The density of the atmosphere affects the drag against Tiangong-1’s orbital speed. As Tiangong-1 loses energy due to drag, it falls towards Earth.
“The space debris team at ESA have adapted their reentry forecast over the last 24 hours to take into consideration the conditions of low solar activity. New data received overnight gave further confirmation that the forecast window is moving to later on 1 April,” ESA officials said in an update from 5 a.m. EDT (0900 GMT).
“The team now are forecasting a window centered around 23:25 UTC on 1 April (01:25 CEST 2 April), and running from the afternoon of 1 April to the early morning on 2 April. This remains highly variable.”