Ageing satellite prepares for a final move as a new era approaches

Meteosat-8, the first of the Meteosat Second Generation (MSG) satellites, could produce a higher-resolution image of Europe and Africa twice as fast as its first-generation counterparts – every 15 minutes. This was the start of a new era of satellite meteorology in Europe.

Now, as EUMETSAT prepares to move Meteosat-8 to its final resting place in the “graveyard orbit”, Europe is on the cusp of another leap forward in satellite meteorology.

Meteosat-8’s lifetime of service

Meteosat-8 is the world’s longest-serving geostationary meteorological satellite.

“That doesn’t happen by accident,” EUMETSAT’s head of Flight Operations, Gareth Williams, said.

“It’s a result of excellent spacecraft design and construction, led by Thales Alenia Space, and careful operations by EUMETSAT.

“We have taken a satellite that was originally designed to function for a minimum of seven years and used it to generate useful data for 20, almost three times as long.

“This really is a remarkable achievement and shows that the MSG system has delivered extraordinary value for money to our member states, which fund our satellite systems.”

EUMETSAT’s Meteosat Spacecraft Operations Manager Flavio Murolo said EUMETSAT was able to extend Meteosat-8’s lifetime, and that of its instruments, well beyond expectations by operating the spacecraft efficiently.

“Crucially, we’ve been able to ensure we have enough propellant left over to move Meteosat-8 out of harm’s way of other satellites in the geostationary orbit, in line with space debris minimisation standards, now that it is at the end of its operational life.”

Over its operational life, Meteosat-8 produced about a million images of Europe, the whole of Europe and Africa, or the Indian Ocean, its islands and surrounding countries.

It has monitored countless storms and severe weather events during that time, helping national weather services to provide timely warnings to their communities and civil authorities.

MSG satellites produce images by spinning – 100 times per minute – and taking an image of one “line” of the view below with each revolution. These lines are sent back to EUMETSAT’s headquarters one at a time, where they are essentially assembled to form a complete image of Europe every 5 minutes, or of Europe and Africa every 15 minutes.

Meteosat-8 has made a dizzying one billion revolutions, at least, over its lifetime while completing 7,366 orbits of the Earth. That’s the equivalent of 5,000 trips to the moon.

EUMETSAT disseminated the last image taken by Meteosat-8 on 1 July. But the spacecraft will continue to make a valuable contribution to EUMETSAT until October, when it will be moved one last time.

Testing times

“Before moving Meteosat-8 to the graveyard orbit, we are running a series of technology tests on the spacecraft and its instruments,” Murolo said.

“These tests will give us a whole range of valuable information that will help us get the most out of the three remaining MSG satellites and their instruments. These tests will even give us information useful for the operation of the third generation Meteosat satellites, which will begin to be deployed from the end of this year.

“They involve special imaging tests and experimental use of equipment, in conditions which are at the edge - and sometimes beyond - the mission design, and finally, the end-to-end validation in orbit of new recovery procedures that can only be tested on a post-operational satellite.”

The move to the graveyard orbit

Murolo said that, at the same time, preparations for Meteosat-8’s re-orbiting in October were continuing.

EUMETSAT’s MSG satellites were designed before the establishment of guidelines for the safe disposal of satellites which aim to minimise the risk posed to those spacecraft still operating on increasingly crowded orbits.

“EUMETSAT is committed to ensuring a safe space environment and will move Meteosat-8 to what is known as a graveyard orbit, well above that used by operational geostationary satellites, and deplete all forms of energy present on board the satellite,” he said.

Enrique Ordas Felices, MSG spacecraft operations team leader, said to get Meteosat-8 to the graveyard orbit, all of the spacecraft’s remaining propellant would be used.

“We’ve carefully calculated how much propellant is left and this will be used for two large re-orbiting manoeuvres,” Ordas Felices said.

“These manoeuvres will raise the satellite at least 247km above the geostationary ring. Once there, we will reduce the energy on board the spacecraft by reducing its spin rate from 100 down to 20 revolutions per minute.

“By doing this, and switching off all electrical systems, we will ensure the long-term stability of the satellite and minimise the risk that the satellite could break up, generating debris that would pose a threat to other operational satellites.”

And that will be the final goodbye for Meteosat-8 after a very long and productive life

The future

Just weeks after Meteosat-8 reaches its final destination, the first of EUMETSAT’s Meteosat Third Generation (MTG) satellites will be launched.

The MTG system will build on and improve the contributions to satellite meteorology made by the previous generations.

When the system is fully deployed, MTG satellites will produce an image of Europe every 2.5 minutes, and an image of Europe and Africa every 10 minutes – in significantly higher resolution than MSG imagery.

This, combined with new instruments to be flown on the satellites, will enable European meteorologists, for the first time, to follow the full life cycle of storms – from initial instability in the atmosphere before clouds form, through to lightning strikes.

So, as the life of the first MSG spacecraft comes to an end, Europe stands once again at the start of a new era of satellite meteorology.