Just weeks after celebrating its tenth year in orbit, communication with
the
Envisat satellite was suddenly lost on 8 April. A team of engineers has spent
the last month attempting to regain control of Envisat, investigating possible
reasons for the problem. Despite continuous commands sent from a widespread
network of ground stations, there has been no reaction yet from the satellite.
The team has been collecting other information to help understand the
satellite's condition. These include images from ground radar and the
French Pleiades satellite. With this information, the team has gradually
elaborated possible failure scenarios. One is the loss of the power regulator,
blocking irreversibly telemetry and telecommands. Another scenario is a short
circuit, triggering a 'safe mode' - a special mode ensuring
Envisat's survival. A subsequent anomaly may have occurred during the
transition to safe mode, leaving the satellite in an intermediate and unknown
condition. The investigation team's assessment is that the chances of
recovering Envisat are extremely low.
Therefore the end of the Envisat satellite operations is being declared. The
investigation team will nevertheless continue attempts to re-establish contact
while considering failure scenarios for the next two months.
The outstanding performance of Envisat over the last decade led many to
believe that it would be active for years to come, at least until the launch
of the follow-on Sentinel missions. However, Envisat had already operated for
double its planned lifetime, making it well overdue for retirement.
With ten sophisticated sensors, 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. Envisat provided crucial Earth observation data not only to
scientists, but also to many environmental services, such as monitoring floods
and oil spills.
Now with the end of Envisat's mission, the launch of the upcoming GMES
Sentinel satellites has become even more urgent to ensure the continuity of
data to users, improve the management of the environment, understand and
mitigate the effects of climate change and ensure civil security.
See also Press Release on the ESA Portal at
http://www.esa.int/esaCP/SEM1SXSWT1H_index_0.html
Envisat satellite was suddenly lost on 8 April. A team of engineers has spent
the last month attempting to regain control of Envisat, investigating possible
reasons for the problem. Despite continuous commands sent from a widespread
network of ground stations, there has been no reaction yet from the satellite.
The team has been collecting other information to help understand the
satellite's condition. These include images from ground radar and the
French Pleiades satellite. With this information, the team has gradually
elaborated possible failure scenarios. One is the loss of the power regulator,
blocking irreversibly telemetry and telecommands. Another scenario is a short
circuit, triggering a 'safe mode' - a special mode ensuring
Envisat's survival. A subsequent anomaly may have occurred during the
transition to safe mode, leaving the satellite in an intermediate and unknown
condition. The investigation team's assessment is that the chances of
recovering Envisat are extremely low.
Therefore the end of the Envisat satellite operations is being declared. The
investigation team will nevertheless continue attempts to re-establish contact
while considering failure scenarios for the next two months.
The outstanding performance of Envisat over the last decade led many to
believe that it would be active for years to come, at least until the launch
of the follow-on Sentinel missions. However, Envisat had already operated for
double its planned lifetime, making it well overdue for retirement.
With ten sophisticated sensors, 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. Envisat provided crucial Earth observation data not only to
scientists, but also to many environmental services, such as monitoring floods
and oil spills.
Now with the end of Envisat's mission, the launch of the upcoming GMES
Sentinel satellites has become even more urgent to ensure the continuity of
data to users, improve the management of the environment, understand and
mitigate the effects of climate change and ensure civil security.
See also Press Release on the ESA Portal at
http://www.esa.int/esaCP/SEM1SXSWT1H_index_0.html
