You have to wonder sometimes whether it is a rollercoaster that Europe plans on sending to Mars rather than a rover – such are the ups and downs and the sweeping curves on its ExoMars project.
ExoMars: Another evolution beckons
The rover was originally envisaged as a small-ish technology demonstration mission which could show that Europe was able to land on the Red Planet, trundle around to interesting places, and drill beneath the surface.
The science would concentrate on looking for signs of past or present life. But the concept for achieving all this has gone through iteration after iteration.
Now we hear that the finished design for ExoMars, which was presented at the end of last year, will have to be re-written once more.
Engineers are being asked to scope something new – bigger perhaps, better perhaps, but something new… again.
The idea of a European exobiology rover at the Red Planet was first mooted in 1999, and after a series of studies its formal implementation as a project was approved in 2005 by European Space Agency member states.
But almost immediately, the robot concept started to grow in size as the ambitions for what it could and should achieve also grew.
Soon, it was too big to fit on a Soyuz rocket and needed an Ariane or Proton launcher to send it on its way. And, as is often the case with complex space projects, its projected costs rose as well. I don’t think many of us were that surprised when its scheduled launch was pushed back, and pushed back, and back again.
The decision in 2009 of Nasa and Esa to merge their exploration programmes at the Red Planet offered a way out of this cul-de-sac.
For Europe, it meant the ExoMars rover could hitch a free ride on an American rocket in 2018.
The US wanted to send another rover of its own at that time, so as long as the two robots could fit into the same landing mechanism together everything ought to be fine. But recent events have upset this tidy arrangement.
The US has decided the cost structure envisaged for 2018 simply cannot be afforded in the current fiscal environment.
So Europe finds itself changing direction once again on ExoMars.
It is now proposed that the European robot and the American vehicle planned to accompany it in 2018 be combined into a single rover.
New drawing needed: The idea had been to send ExoMars and a US rover together on the same mission opportunity
This new robot is likely to be substantially bigger than either of the two previous concepts.
It is being described as a “European” vehicle. It should incorporate all the instruments planned for ExoMars, including the drill to go below the Martian surface. But it should carry some American instruments, and its manipulator arm will come from the US, as will a system to package – or cache – rocks.
Both Nasa and Esa have this idea that 2018 should be the start of “Mars sample return” – the objective of bringing rocks back to Earth for study in the lab. In 2018 they will begin this process by finding the right rocks and packing them up. A later mission will be despatched to try to retrieve them.
The key thing about this new-evolution rover is that it borrows heavily from the equipment designed for the upcoming American "MSL-Curiosity" rover. This is one way of keeping costs as low as possible.
MSL-Curiosity is big: It weighs about 900kg
Curiosity launches at the end of this year and is due to land in the August of 2012. I don’t know if you’ve seen how this rover intends to get down on to the surface, but the idea is that it will be lowered to the ground by a rocket-powered skycrane.
Nasa and Esa want to re-use this architecture for 2018. Thefore, all of the landing gear – the entry capsule, the skycrane, and the tether system that does the actual lowering – will come from the US.
So there you go. All the design work in Europe that has been done since 2005 is going to have to go through yet another iteration.
Perhaps you’ve been to an event in the UK where you’ve seen a prototype of the ExoMars chassis – a six-wheeled trolley called either Bridget or Bruno. Well, put that to the back of your mind because engineers will soon have to produce another one to fit with new specifications.
Well in excess of 100 million euros has been spent on the ExoMars programme to date. Critics will raise their eyebrows at this, given the latest developments, but it would not be true to say all this money has somehow been wasted.
Much of the technology developed for ExoMars will find its way into the new vehicle. But you would be forgiven if you had a little voice in the back of your head saying, “are we nearly there yet?”.
2018 is really not that far away in the context of space mission preparation. Engineers on both sides of the Atlantic are now going to have to crack on and deliver a workable concept.
It will be interesting also to see how much of the development of this vehicle is led from the UK.
Britain has committed 165 million euros to ExoMars to secure primacy for itself on the rover.
Will we now see a big, six-wheeled robot being assembled in the UK? I certainly hope so.