Long journey to the skies

When the power was temporarily switched off on EUMETSAT’s Meteosat Third Generation first imager satellite (MTG-I1) in Cannes, France on 14 September, Pierre Armand, MTG Programme Director at Thales Alenia Space allowed himself to breathe a short sigh of relief.

The moment signalled MTG-I1 was now ready to embark on the final stages of the spacecraft’s much-anticipated journey to a geostationary orbit, some 36,000 kilometres above the Earth’s surface. Once in position, the satellite will provide data essential for weather services such as ‘nowcasting’ – very short range forecasts of fast-evolving weather like thunderstorms.

But before MTG-I1 takes to the skies, Armand — and thousands of meteorologists, engineers, remote sensing scientists, training officers, and others who have helped turn the mission from blueprint to reality — will have to bear a few more heart-in-the-mouth moments.

This begins now, with MTG-I1 embarking on a two-week voyage by ship from southern France to the satellite’s launch site on the other side of the Atlantic, in Kourou, French Guiana.

“For the past two years, our teams in Cannes have been working double and triple shifts — and very often during the weekends — to get everything ready on time,” says Armand, who leads a team of more than 300 experts at Thales Alenia Space, a space manufacturer that is responsible for building the MTG-I satellites and Flexible Combined Imager payloads as part of the MTG programme.

The company, together with OHB as major partner, is the main contractor on the MTG programme that will ultimately include four imager and two sounder satellites.

“We are now ready to move to next stages and it’s very exciting to see the last crucial steps being taken to get MTG-I1 safely to the launch pad, where the Ariane-5 rocket will propel the satellite into orbit.”

Rising to shipment challenges

In its container, MTG-I1 is the size of a small bus, weighing around 20 tonnes (the satellite alone weighs roughly 2000 kilogrammes). As an oversize load, the satellite necessitated a police escort to chaperone a convoy carrying it from Cannes to the port at Fos-sur-Mer, near Marseille, some 300 kilometres away.

“Thankfully we now have a lot of experience transporting satellites by boat,” Armand says. “I am very confident MTG-I1 will arrive safe and sound at its destination on time for the next stages of the mission.”

To prepare MTG-I1 for the voyage, the spacecraft has been carefully packed into a shipping container that also serves as a cleanroom to minimise risks of the satellite coming into contact with contaminants that might damage delicate instruments.

Specialists have also spent several days loading seven freight containers’ worth of hardware, maintenance and backup equipment, triple checking every item that might be needed for MTG-I1 to take to the skies.

“One of the biggest challenges is making sure that we take everything we need — from computer wires to backup generators,” Armand says. “If even one small item is missing, it could set us back days.

“If a larger item that cannot be couriered by a commercial plane is damaged or missing, then it could become very complicated and even result in a delay to the launch despite how creative we usually are to put in place a solution. Some items are mission-critical, others packed ‘just in case’. But every component will play a vital role in ensuring that MTG-I1 has a successful launch.”

Expecting the unexpected

The MTG team is ready for almost every possible eventuality, with experts keeping a watchful eye on the conditions of the precious cargo during its long voyage.

“Although the satellite will be very securely packed, it's crucial to ensure that humidity, pressure, and temperature are maintained at ambient levels,” Armand says. “For example, just a few days without air conditioning could cause big problems for the satellite’s instruments.

“We have also built in a few days of buffer time should the ship have to change course because of storms or other difficult weather conditions.

“On the other hand, we have designed the satellite to withstand a rocket launch, so in many respects it is very robust. Although the launch will only last a few minutes, the levels of stress on equipment during this time will be far beyond what we expect at sea.”

Nevertheless, when MTG-I1 reaches the harbour of Kourou in mid-October, Armand says he will breathe another short sigh of relief. But there will be more exhilarating moments ahead.

“Having the satellite ready for the voyage to Kourou is already an amazing achievement,” says Armand. “But there are still some key tests to come and several months of intense activity before MTG-I1 is ready for launch.

“Once the satellite is in French Guiana, we will repeat rigorous tests that we have already carried out in Cannes to verify the satellite is still in good shape.

“Then, we have to prepare for the transfer to the rocket. This will include a critical phase when we load propellants. Rocket fuel is of course highly flammable and guaranteeing the safety of people and equipment is paramount.”

Once the satellite is transferred on top of the Ariane 5 rocket and to the launch pad, Armand’s team will then oversee the final checks and wait patiently for the green light that will signal ‘all systems go!’.

“The launch will be a very nerve-wracking time. MTG-I1 will embark on one of the most critical parts of the mission: its launch and early orbit phase,” he explains. “Once separated from the launch vehicle, engineers will take control of the satellite, activate its subsystems, guide its orbit and orientation, and undertake an array of other critical manoeuvres.”

Two weeks later, MTG-I1’s instruments will be switched on and a long period of verification will begin.

Looking forward to launch

But before that, if all goes to plan with the satellite’s launch into space, a big celebration will be in store.

“When the satellite is launched it will be a huge event,” Armand says. “We need to make sure that we are completely ready so that there are no red flags, that the satellite passes all of its critical stress tests, and the only thing that we need to worry about is the weather.

“MTG is a massive programme that has pushed the boundaries of what is technically achievable. This has only been possible thanks to tremendous collaboration between all parties involved, including EUMETSAT, the European Space Agency, Thales Alania Space, OHB, and many other organisations.

“I have personally been working on MTG for more than a decade now, and it’s been a tremendous journey so far. With the operation of the satellite and follow-up missions such as a second imager satellite, a sounder satellite, and their replacements, the programme still has a long way to go.

“But I am looking forward to the time when MTG-I1 is fully operational, the pressure is down a little bit, and we can begin to enjoy the impact that this fantastic programme will have on monitoring weather, climate and environment from space.

“We are very excited about the impact MTG will have on weather forecasts in the coming decades, thanks to the quality and accuracy of the datasets that will be downloaded from the spacecraft to be used by meteorological experts.

“MTG is going to help save lives while paving the way for new kinds of services for Europe’s and Africa’s citizens.”

Author:

Adam Gristwood