Monthly Archives: April 2012

MetOp-B launch postponed

Eumetsat and the European Space Agency (ESA) have been informed by the launch service provider, Starsem, that the launch of the MetOp-B satellite by a Soyuz rocket, scheduled for 23 May from Baikonur, had to be postponed. This is due to additional measures required to ensure the availability of safe drop zones for parts of the launcher after lift-off.
 
The launch has been postponed for some weeks, until appropriate measures are implemented. It is expected to take place in the second half of July, after the launch of the geostationary MSG-3 spacecraft, which is scheduled for 19 June from CSG, Europe’s Spaceport in French Guiana.

MetOp fairing: scrupulously clean

From Phi-Hung (ESA), Baikonur, 24 April

The Soyuz fairing that will encapsulate MetOp, which arrived at the Baikonur Cosmodrome in March, has passed a critical inspection.

Fairing check

After the inside and outside of the fairing halves had had a through clean, they were transferred to the cleanroom ready for a ‘cleanliness inspection’ by the team from ESA, with members from Astrium and Eumetsat in attendance.

Fairing check with UV light

This is a meticulous check where every inch of the fairing is carefully looked over using a white light and a UV lamp to make sure that it is free of ‘foreign object debris’ such as dust, particles, fibres, glue.

Using the two different lamps means that the team can see into every nook and cranny to ensure that the fairing is scrupulously clean.

Team infront of fairing

Both halves were found to be in an excellent state of cleanliness and were, accordingly, accepted by the team for the next step.

The fairing halves are being stored temporarily in the cleanroom, but a further inspection will also be carried out just before MetOp is encapsulated.

 

MetOp checked for fuelling

From Nick (ESA), Baikonur, 24 April

Final health checks on MetOp-B’s Reaction Control System (RCS) have been completed in preparation for fuelling.

Checking the Reaction Control System

The RCS consists of tanks that will contain the Hydrazine fuel pressurised with Helium gas, and several small thrusters that can be used to adjust the satellite’s orbit after separation from the launcher.

The specialist team from Astrium Ltd, who prepare the RCS for launch, arrived in Baikonur in mid-April and quickly began to test the RCS to make sure everything was working correctly following shipment. 

Tests include functional checks of the valves and pressure transducers, a calibration of the pressure sensors and tests to ensure there are no leaks and that the satellite is safe before activities begin to load the propellant.  A Helium-tuned mass spectrometer is used to detect and measure any leakages.

In SCAPE suits

In parallel, the team also prepared the equipment for propellant loading.  Hydrazine is a hazardous and highly flammable chemical so has to be handled very carefully to ensure the safety of the team and the satellite.  There are also health risks if in contact with skin or inhaled. 

For this reason, the team have to wear what is known as a SCAPE suit.  This stands for Self Contained Atmospheric Protection Ensemble and is basically a protective suit with an air supply that allows the wearer to work safely. The operators are specially trained in working with Hydrazine whilst wearing these suits.

The RCS tests have all been completed and everything is ready to begin the loading of the propellant, making MetOp-B ready for launch.

 

MetOp readied for fuelling

From Damiano (ESA), Baikonur 17 April

The MetOp launch campaign has now reached the end of the first preparation phase during which a number of activities have been successfully carried out.

A team effort!

Straight after the arrival at the Baikonur Cosmodrome, the MetOp Payload Module and the Service Module were mated together. MetOp was then tested to verify the health of the instruments and equipment onboard.

Following the functional verifications, we have performed some mechanical verification. The building up of the spacecraft has continued with the integration of the solar array, the pyrotechnical devices and the finalisation of the thermal blankets – the multilayer insulation.

Close inspection of MetOp

To close this first phase of operations, we performed a first ‘launch countdown rehearsal’ to check the procedure to be used during the real countdown.

MetOp is now ready to be transferred to another facility, inside the Cosmodrome, where it will be filled with propellant.

Container close to MetOp for transfer to HPF

Container close to MetOp for transfer to HPF

After this very critical operation the satellite will return back to the UCIF to start the combined operation with the launcher that will finally end up with MetOp being encapsulated in the upper composite of the launcher!

 

MetOp wrapped

From Sylvain (ESA), Baikonur, 11 April

Temperature control is very important to ensure that all of MetOp’s electronics and instruments function optimally in space. When in orbit around Earth, the satellite passes between sunlight and shadow. Consequently, it has to withstand extreme swings in temperature: from below –100° C to above 100°C.

Astrium team finalising a MLI blanket on payload module

This is why a dedicated thermal design was chosen to keep the electronics within a more ‘gentle’ range of temperatures, generally between 0–20°C. This is done by using a combination of active thermal control measures such as electrical heaters and passive methods such as space-qualified paints, tapes and multilayer insulation (MLI), essentially on the external surfaces of the satellite.

The MLI is literally a ‘smart’ thermal blanket. Not only does it prevent heat from the Sun getting inside the spacecraft, but it also prevents the heat produced by the electric heaters being dissipated into outer space.

MetOp-B being moved to a horizontal position for MLI finalisation

In the Baikonur Cosmodrome cleanrooms the installation of the pieces of MLI has been finalised by the Astrium teams and inspections to confirm proper installation were conducted.

This is a meticulous task since there are several ways to attach the MLI. Some pieces are attached via Velcro (similar to the stuff on your kids’ shoes!), some others are punctured in order to insert a stud and closed by a clip. The last pieces are actually taped to the structure. These attachments techniques have to be carefully controlled so that the vibrations during launch don’t cause the MLI pieces to detach.

Another critical aspect to check for any holes or cavities in the MLI. Indeed the smallest hole might lead to a leakage of heat, or even worse trap heat from the Sun. The sun-trapping effect occurs when a ray from the Sun enters a hole (or cavity) and is partly absorbed and partly reflected many times by the internal surfaces. This leads over-heating of the spacecraft surfaces and at worst it could even damage critical elements.

That is why the upmost care is taken by the integration and validation teams while inspecting the installed MLI.

However, it is with pleasure that we can announce that the main MLI activities have been completed successfully. The last piece of MLI will be added just before the MetOp satellite joins the Soyuz Fregat.

Next step is the countdown rehearsal.

Until our next entry in the blog, do not forget the thermal engineers motto:

“Patience et longueur de temps font mieux que force ni que rage!”

A week in pictures: MetOp-B nears launch configuration

From ESA's launch campaign team, Baikonur, 3 April

Setting up for alignment

Last week was busy, but things went well. The main activities included the pyro-connection, alignment, solar array integration and finishing off applying the multilayer insulation.

To take all the alignment measurements, the satellite was positioned vertically on a 'rotary table'.

... and on to the rotary table

Measurements were taken using reference mirror cubes and thodolite to verify the instrument and the attitude and orbit control system were aligned. In total, 58 measurements were taken.

Ready to receive the solar array

Then came the task of joining the solar array to the satellite. To do this satellite was tilted and rotated to receive the array.

The integration the solar array was finally completed and tested.

Mini deploymentSolar array integration nears completion

In parallel, the multilayer insulation was applied to the satellite and by the end of the week MetOp-B was near to its launch configuration.

Nearing launch configuration

Fuelling and red-tag removal will follow!