ESA's ice mission

The mission's objectives remain the same as before – to measure ice thickness on both land and sea very precisely to provide conclusive proof as to whether there a trend toward diminishing polar ice cover, furthering our understanding of the relationship between ice and global climate.

It is now generally agreed that the Earth's atmosphere is getting warmer, and although the impact of climate change is expected to be amplified at the poles, it is extremely difficult to predict what effect this is having on the polar ice cover.

From an altitude of just over 700 km and reaching latitudes of 88°, CryoSat-2 will monitor precise changes in the thickness of the polar ice sheets and floating sea ice. The observations made over the three-year lifetime of the mission will provide conclusive evidence of rates at which ice cover may be diminishing.

The CryoSat-2 Flight Operations Control Centre is located at ESOC, Darmstadt, Germany.

 
 

	Nic Mardle

The Flight Control Team
 
The CryoSat Flight Control Team will operate from a Dedicated Control Room, located at ESOC.

Spacecraft Operations Manager Nic Mardle, from the UK, is an experienced spacecraft manager who assembled and trained the first CryoSat Flight Control Team in 2003-05.

Everyone at ESOC watched in profound disappointment as the first CryoSat mission, launched 8 October 2005 on a Rockot launcher, ended in failure; CryoSat was totally lost just a few minutes after launch and before the ESOC Mission Control Team even had a chance to acquire the satellite.

Although CryoSat-2 is in theory a rebuild there are plenty of challenges to keep the team busy, including over 80 changes to the satellite as well as new hardware and software available for the ground control systems and new members in the team. All the elements must be revalidated and tested prior to the new launch date, so that the Flight Control Team will be equally prepared as the last time to look after command and control, on-board software maintenance and mission planning, as well as interfacing with other ESOC teams, including Flight Dynamics, Ground Facilities and Software Support.

Between now and the planned 2009 launch, Mardle will continue working on the overall ground control architecture, defining flight control procedures and assembling and training the Flight Control Team.

	CryoSat in the Dnepr vehicle

For CryoSat-2, the LEOP (Launch and Early Orbit Phase) period will be almost unique, as the satellite does not have any deployable solar panels; in fact the satellite has no moving parts at all, except for some valves in the propulsion system.

This has enabled a very significant cost saving, but does pose some problems for the provision of adequate solar power in CryoSat-2's unusual orbit. The solar panels are fixed to the satellite body, forming a 'roof' at a carefully optimised angle, which provides adequate power under all orbital conditions and still fits within the launch vehicle.

Preparations and rehearsals will take place during the pre-launch period, and mission operations proper will commence at the separation of the satellite from the launcher and continue throughout the 3.5-year nominal lifetime of the mission. The FCT at ESOC will oversee mission planning, spacecraft status monitoring, spacecraft control, orbit determination and control, attitude determination and control and on-board software maintenance, among others. These are all tasks which are common to any low-earth orbit mission such as CryoSat.

	Kiruna station

In addition, all of the considerable science data processing will be done locally at Kiruna by an automated system of computer workstations.

	This mission is scheduled to use SCOS-2000

Mission planning will be preformed at ESOC while the payload will be coordinated by ESA/ESRIN; the detailed plan will be uploaded regularly to the satellite from Kiruna. The large amount of data received from the payload, and in particular from the altimeter, will be pre-processed at Kiruna, before being sent to ESA/ESRIN for final processing and data dissemination to the users.
 
 

	Diagram of ground segment infrastructure

An important aspect of the CryoSat-2 Ground Segment is that it had been designed for operations with a low level of manpower.

Furthermore, remote operations and troubleshooting can be performed on all systems located in Kiruna.

	CryoSat measuring freeboard sea-ice

Unlike most satellites, CryoSat does not have any deployable solar panels; in fact the satellite has no moving parts at all, except for some valves in the propulsion system.

This has enabled a very significant cost saving, but does pose some problems for the provision of adequate solar power in Cryostat-2's unusual orbit. The solar panels are rigidly fixed to the satellite body, forming a "roof" with a carefully optimised angle, which provides adequate power under all orbital conditions and still fits within the launch vehicle.