A flash of light cuts through the tropical night. Thunder echoes through the jungle and the air fills with smoke. It’s 10:45 pm in French Guiana and an Ariane rocket has just taken off from the Guiana Space Centre, leaving a trail of fire.
With a rush and a hiss, it cuts through the air towards the heavens until only a small ball of fire is visible in the dark. A few moments later, back on the ground, a group of scientists celebrate, clapping their hands and embracing each other.
It’s not just any old launch that’s just taken place here, deep in the South American rainforest, where dozens of rockets are propelled upwards from the base at the Guiana Space Centre every year.
This time, the Ariane 5 rocket is carrying especially valuable cargo: a double probe that, over the next seven years, will make the journey to Mercury.
BepiColombo is a joint mission of the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA). It is one of the ESA’s most challenging missions yet — and, with a budget of more than US$2.3 billion, also one of its most expensive.
“When people understand what we are doing here, they are going to be fascinated,” beams Johann-Dietrich Woerner, ESA director general.
He knows Europe and the rest of the world will be keeping a close eye on the mission — not least because of its hefty price tag.
We know less about Mercury than practically any other planet in the solar system. It has been visited by human equipment only twice before: In 1974, the US probe Mariner 10 managed to chart about 45 per cent of its surface after passing by it three times; and in 2011, US space agency NASA’s Messenger probe spent four years orbiting it.
Now, the ESA wants to know more. The mission was originally due to launch five years ago, but it was delayed due to difficulties with developing the highly complex equipment.
“That’s not a big problem,” says Woerner. “Of course delays are not a good thing. But the important thing with this mission was to be sure that the technology would be 100-per-cent reliable.”
The main challenge is that getting anywhere near Mercury is like travelling into a furnace. The heat from the sun can be felt so strongly on the planet that its surface temperature can easily hover at about 450 degrees Celsius on a normal day.
The outer shells of the BepiColombo probes will heat up to more than 360 degrees while they are orbiting the planet – but the sensitive equipment inside will only work at temperatures up to 40 degrees.
This was a huge challenge for the researchers. Even before the spacecraft reaches Mercury, there are risks. With the complex launch out of the way, it must now travel around 9 billion kilometres – 60 times the distance between the Earth and the sun.
Its maximum speed is 60 kilometres per second, or 216,000 kilometres per hour.
In order to slow down, the double probe will fly past the Earth in 2020, and then also later twice past Venus and six times past Mercury itself. If it goes too fast, it could end up melting in the heat of the sun instead of entering Mercury’s orbit as intended.
“It’s about getting down to a steady speed of 3.4 kilometres per second,” says Eckard Settelmeyer, director of Earth observation, navigation and science at Airbus Defence and Space.
If the probe is successful, once it reaches Mercury, two satellites will break off from its main body and head off on different paths to explore the planet.
The ESA satellite Mercury Planetary Orbiter (MPO) will explore and chart the planet’s surface, while the Japanese Mercury Magnetospheric Orbiter (MMO) will record the planet’s magnetic fields.
Even though the mission has only just begun, Woerner and his team are already planning the next one.
The Juice probe is set to fly to Jupiter in 2022, and plans are already afoot for missions in the 2030s.
Working with other countries is important, Woerner says: “Only through cooperation between nations can we undertake missions that individual nations could not finance alone.”
The 22 member countries of the ESA work closely together, as well as with the US agency NASA, Russian space agency Roskosmos and, as in the case of BepiColombo, JAXA.
It’s not just individual nations that are reaching for the stars – private companies are also starting to explore the opportunities offered by outer space. For example, Elon Musk’s company SpaceX wants to make life on other planets possible, and Amazon founder Jeff Bezos has founded the company Blue Origin to explore business opportunities in the ether.
“Competition drives us,” Woerner says. “That’s true in sport, and also in space. I believe humans will fly to Mars.”
But he’s not keen on the idea of humans colonising other planets. “The Earth is far too beautiful for us to live in a tin can on a planet or a moon,” he says.
For Woerner, our top priority should be saving our own planet – and he hopes that’s something the discoveries of BepiColombo will be able to contribute to. – dpa
