Landing on Mars in 2016
I remember going up to a leading French planetary scientist at a meeting in Paris last year and asking if he was interested in taking part in Europe's mission to land a spacecraft on Mars in October 2016. "No," was his response, "because there is no science on it."
The landing platform will be carried to Mars inside its conical entry shell. The structure will be attached to an orbiter that will study atmospheric gases
There is... just not very much, and it will be very short-lived; this post will attempt to explain why.
Europe's plans for Martian exploration (called ExoMars) have been revised, reviewed and re-scoped so much down the years that you could be forgiven for not having the foggiest idea what's going to happen.
But the plans are now set. Industry submitted the Preliminary Design Review documents to the European Space Agency (Esa) at the end of October, and full implementation is expected to start in April next year.
It's now all a joint affair with the Americans. Europe will build an orbiter and lander for 2016, and then in 2018 both Europe and the US will be sending rovers to the Red Planet. There should be follow-on missions too in 2020 and 2022.
This week, Esa released an Announcement of Opportunity on that 2016 lander. It's basically a call to the research community to come forward with ideas on how to use the lander for science. And, as I said, the resources available will be minimal.
The lander is, first and foremost, a technology demonstration that will prove Europe's ability to get down on to the surface safely. Everything else is considered secondary, including the science.
Europe has not yet landed on Mars. Its one previous attempt - the UK-led Beagle-2 spacecraft - did not call home after making its bid to get to the surface. The intention of the new attempt is to develop a system that can be scaled up for future missions when science will be the priority.
The size of the entire 2016 module is 600kg - that's everything needed to enter the Martian atmosphere, survive the fiery descent, and then make a controlled landing.
A doppler radar will judge the speed and distance to the ground
I've put some pictures in this post which illustrate what the lander will look like and how it will get down.
As always, it's a perilous journey to the surface of Mars.
The surface platform must shed its protective shell after the fiery phase of the entry
An entry capsule with the surface lander inside will be spun off the orbiter a few days before arrival at the Red Planet.
The 2.4m-wide, conical, protective shell will hit the top of the Martian atmosphere at about 5.7km/s (13,000mph).
Pushing hard against the Martian air, its descent will begin to slow. The module's front shield will also get very hot.
A parachute will then be deployed to reduce the rate of fall still further. Finally, the surface platform will detach from the chute and pulse its thrusters.
With speed and distance information coming from a doppler radar, the platform should bring its velocity down to zero about a metre above the ground.
The lander has no legs, so it simply dumps down. A crushable material on the underside of the platform should prevent any damage from rocks that might be lying right on the point of contact.
The entire landed mass should be about 300kg.
One of the great unknowns in all this will be the Martian weather, and engineers are preparing for very unfavourable conditions. Vincenzo Giorgio is leading the industrial side of the ExoMars project at prime contractor Thales Alenia Space (Italy). He told me:
"Because of the hyperbolic insertion we cannot control when we are going to land on Mars, and unfortunately we will be in the middle of the dust storm season. That's the worst scenario in which to try to land on the planet. Therefore we have to design for very strong horizontal winds."
The surface platform will not carry solar panels or a radioisotope power source. It will have a battery and that's it. This will give the science sensors built into the platform at least four days, perhaps eight, to gather their data before dying.
The orbiter should pass overhead a couple of times while the battery is still alive, allowing the data to be up-linked and relayed back to Earth. But what sort of data?
The mass available on the platform for science instrumentation will be just three kilograms. This instrumentation will comprise environmental sensors. They'll be gathering information about pressure, the amount of dust in the atmosphere, perhaps ultraviolet conditions, and the like. It's all to be decided. That's the point of an AO. Scientists bid for what they'd like to do.
There may or may not be a camera. It's possible no researcher in Europe will propose one. I doubt that somehow. Can we really send a probe all the way to the surface of Mars and not have a photo? Dr Jorge Vago is the ExoMars project scientist at Esa. He told me:
"The objective is geared towards technology demonstration. We are trying to make a little bit of room for some science on a spacecraft that is really, really full of systems that are required for landing. This is not the type of landing system you would use to land, let's say, a Beagle-2 type of spacecraft. It is really aiming to demonstrate a large system without the payload, more or less.
"This will be the first mission in very long time that is landing in the middle of the statistical dust storm season, and the lander will be designed to cope with that. All other missions avoid this time of the year like the plague. And as such it will be a unique opportunity for characterising the entry, descent and landing atmosphere.
"One of the things we hope to do is measure pressure because there are some discrepancies between the results of Viking and Pathfinder that are driving the modellers crazy, and they are crying out for a new measurement to try to settle the issue. And in times of high dust content, there may be electro-static discharges in the atmosphere we could look for.
"There are many measurements that could be made in a few days and that would be very useful. Of course, it will not be the same level of science return that you might get from an environment observatory that stays on the surface for a full Martian year. Nevertheless we think we can get useful results."
You can live the dive to Mars' surface by listening to Maurizio Capuano. He is the entry, descent and landing demonstrator model programme manager at Thales Alenia Space.
I asked him to describe the whole sequence from the moment the capsule comes off the orbiter. Click on the box below and you'll get an idea of the complexity of the endeavour.