May 9, 2012
ESA Declares End To Lost Envisat’s Mission
After spending more than 10 years in space, orbiting the Earth more than 50,000 times, Envisat´s mission has ended, according to a report from ESA today. The satellite had been lost on April 8, 2012, and though teams had tried their best to re-establish contact with the eight-ton satellite, they have now declared its mission has ended.
According to ESA, a team of engineers has spent the past month trying to regain control and communication with Envisat from a variety of ground stations to no avail. Furthermore, this team had investigated multiple failure scenarios before ultimately deciding the satellite was lost.
ESA says the loss has come as a bit of a surprise, as there was no sign of trouble or degradation leading up to the mysterious disappearance. The team has been collecting as much information as they can from just before the disappearance to better understand the satellites condition.
From their investigations, the team has posited the satellite could have failed due to a loss of the power regulator which could block both telemetry and tele-commands.
Another possible scenario suggested by ESA is a short circuit, which would have triggered a “safe mode” meant to protect Envisat in the event of any danger. The ESA team also suggests a short circuit could have caused a malfunction as Envisat transitioned to safe mode, leaving it lost in an unknown location.
The team at ESA isn´t giving up all hope on locating Envisat, however. According to the press release, the investigation team will continue to look for the lost satellite as it considers different failure scenarios.
ESA had high hopes for the veteran satellite, expecting it to last for many more years into the future. As it stood, Envisat had already been space-borne for twice as long as it was meant to be, making it a trusted satellite as well as overdue for retirement.
In a bit of a digital obituary, the ESA press release lists some of Envisat´s achievements and capabilities.
According to ESA:
• Envisat has observed and monitored Earth´s land, atmosphere, oceans and ice caps during its ten-year lifetime, delivering over a thousand terabytes of data.
• An estimated 2500 scientific publications so far have been based on this information, furthering our knowledge of the planet.
• During those ten years, Envisat witnessed the gradual shrinking of Arctic sea ice and the regular opening of the polar shipping routes during summer months.
• Together with other satellites, it monitored the global sea-level height and regional variations, as well as global sea-surface temperatures with a precision of a few tenths of a degree.
• Years of Envisat data have led to a better understanding of ocean currents and chlorophyll concentrations.
ESA has also used Envisat to monitor floods and oil-spills, as well as provide information to civil protection agencies during times of natural and man-made disasters.
With the end of Envisat´s mission, the ESA will turn their attention to launching the new GMES Sentinel satellites.
ESA plans to launch 5 such Sentinel satellites to be used by the Global Monitoring for Environment and Security (GMES) program.
Sentinels´ 1,2 and 3 are slated to be launched into space in 2013, though these launches could be cancelled due to financial issues within the ESA.