Space diary: Fuelling up

Two weeks to go before launch and the Envisat team is busy testing rocket engines, fuelling and packing up equipment.

Outside the mosquitoes are starting to bite, as project manager Derek Todman reports in his latest diary for BBC News Online.

Friday 8 February

The second pair of tanks was filled this morning and this afternoon all the fuel-filling equipment was cleared out of the fuelling hall, leaving only the pressurisation equipment. This means that the area is safer to work in, but care still has to be maintained as the satellite is now fuelled.

In parallel to the satellite operations, we are packing up all the equipment no longer required to support the activities for launch.

There is a lot of packing to do as 300 tonnes of equipment was shipped out and the satellite alone weighs eight tonnes. Today, we started to disassemble the satellite integration stand, which weighs 30 tonnes and will be shipped out on three lorries.

This equipment was shipped down by sea and air. Most of it will go back by sea with a small amount of equipment going back by air, in particular the equipment needed at the ground station as spares.

A series of electrical tests were successfully carried out on the vulcan engine today. This is the first stage engine of the Ariane 5 rocket and is fuelled by liquid oxygen and liquid hydrogen. It is the engine that is at the bottom of the middle section of the Ariane.

Saturday 9 February

This morning we completed the initial pressurisation of the tanks to 18 bar (about 250 psi). Before final adjustment, the temperature is allowed to stabilise, as the temperature will rise during pressurisation.

Once the area had been declared safe at the end of the hazardous operations, the "build" team came on to complete the blanket installation around the thrusters.

The satellite has a lot of blankets and these are installed to ensure that the satellite does not get too cold. For the propulsion system, we have to make sure the temperature never gets below about 4 C, otherwise the fuel will freeze and the thrusters will not work.

The sun came out today, and, after all the rain, the conditions are perfect for the mosquitoes. Most of us have now been bitten or stink of mosquito repellent.

Sunday 10 February

The satellite after fuelling

The final adjustment of the tank pressure was made this morning to 19.1 bar (280 psi), which completes the fuelling activities. All the fuelling equipment has been moved to another building where it will be decontaminated.

The large cover on the photo of the satellite is over the solar array. This is purged with nitrogen to ensure that the humidity is kept to a minimum to ensure the array operates correctly in orbit.

Monday 11 February

It has been a quiet day today. The caps for the propulsion system were sealed so that they cannot come loose during launch. This afternoon the link between the satellite and the satellite control centre was checked out.

Once we are on the launcher, the satellite and the satellite control centre are approximately 10 kilometres apart. There is a large network between the various sites and in the assembly and fuelling halls. We therefore took the opportunity to verify that all is well before we finally get to the launcher. I am pleased to say all worked well.

The team also went on the safety training course that is mandatory for all personnel working in the final assembly building. Part of this training includes using the emergency evacuation facility - basically a chute. We only went from the second floor to the exit. When the satellite is on the launcher we will have to come down from at least the 9th floor, a drop of about 30 metres. I think I'll stay in my office!

Wednesday 13 February

The team had the afternoon off. I have been asked what we all do on our days off. Once we have caught up on lost sleep there are a number of pastimes that are pursued here: swimming, fishing, golf, cycling, sight-seeing, jungle trekking and canoeing.

Fishing can be a hazardous affair

Golf here is quite interesting as the rough on the Kourou golf course consists of dense jungle.

Generally, most golfers do not try to retrieve golf balls in the rough, and tales abound of finding a snake guarding the ball or troops of monkeys crossing the fairway.

The local fish here are tarpon and catfish and it has been known to catch the odd piranha or electric eel. Their teeth are as sharp as the photo suggests - you should have seen the one that got away.

The vegetation here is typical of a jungle forest and stays green all the year round. The European residents here do complain that they miss the colours of Spring and Autumn.

Thursday 14 February

Another quiet day with no work on the satellite and we just continued packing. This is a good situation to be in - the last thing we want is to be rushing around trying to complete activities at the last minute.

We have taken the opportunity in this period to make sure everything is ready for the last 10 days of activities prior to launch.

The activities on the launcher are progressing according to plan - like us, the team there is doing all the final electrical and mechanical checks to make sure everything is ready to start the last activities to launch.

Forthcoming Attractions:

• Mate with the satellite/launcher interface ring
• Transport to the final assembly hall
• Mate with the launcher
• Complete the last satellite preparation tasks
• Launch