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Artificial intelligence Boosts Science From Mars Searches for Signs of Past or Present Life

Artificial intelligence (AI) being used at the European Space Operations Centre is giving a powerful boost to ESA's Mars Express as it searches for signs of past or present life on the Red Planet.

Since January 2005, Mars Express has been using its sophisticated instruments to study the atmosphere, surface and subsurface of Mars, confirming the presence of water and looking for other signatures of life on and below the Red Planet's rocky terrain.

The spacecraft generates huge volumes of scientific data, which must be downloaded to Earth at the right time and in the correct sequence, otherwise data packets can be permanently lost when the limited on-board memory is overwritten by newly collected data.

Traditionally, data downloading was managed using human-operated scheduling software to generate command sequences sent to Mars Express, telling it when to dump specific data packets. "This is tedious, time-consuming and never really eliminated the occasional loss - forever - of valuable science data," says Alessandro Donati, Head of the Advanced Mission Concepts and Technologies Office at ESA's Space Operations Centre (ESOC), Darmstadt, Germany.

'Smart' Solution to Complex Delivery Problem
But since 2005, AI researchers at Italy's Institute for Cognitive Science and Technology (ISTC-CNR) led by Dr Amedeo Cesta and mission planners and computer scientists at ESOC have been developing a solution to the complex Mars Express scheduling problem by applying artificial intelligence (AI) techniques to the problem.

The result of this work is a new 'smart' tool, dubbed MEXAR2 ('Mars Express AI Tool'), which is now an integral part of the Mars Express mission planning system.

MEXAR2 works by intelligently projecting which on-board data packets might be later lost due to memory conflicts, optimising the data download schedule and generating the commands needed to implement the download. "With MEXAR2, any loss of stored data packets has largely been eliminated," says Fred Jansen, ESA's mission manager for Mars Express.

MEXAR2 has reduced the mission planning team's workload considerably - by 50 percent compared to the old manual method - for generating workable downlink plans. "And because it optimises bandwidth used to receive data on Earth, we have been able to free expensive ground station time for other missions," says Michel Denis, Mars Express Spacecraft Operations Manager at ESOC.

MEXAR2 recently won the 'best application' award at ICAPS 2007, a benchmark international conference for AI planning & scheduling technology.

Europe's First Deep-Space Mission to Fly with AI
AI provides solutions for complex problems, and has now entered the space mission operations field as a value-adding technology. "Mars Express is the first European deep-space exploration mission to fly using an AI tool on the ground, and the technology is boosting science return while reducing time and resource costs," adds Donati.

With MEXAR2's proven success, scientists at both ESOC and ISTC-CNR are working to apply the current AI technology to other problems.

Successful recent work includes the reverse problem of how to optimise the upload of commands to Mars Express, in a project dubbed - somewhat tongue-in-cheek - as 'RAXEM' - for the 'reverse of MEXAR'.

ESA-developed AI technology will also be applied to the 'Advanced Planning & Scheduling Initiative', which is designed to provide AI benefits to other areas and missions, including long term observation planning for ESA's Integral, space-borne gamma-ray observatory.

"It's possible to apply the same AI concepts to future missions, like ExoMars, Europe's first planetary rover mission to the Red Planet," says Donati, adding, "Today's achievement is the starting point for implementing new on-board autonomy concepts for ESA's challenging missions of the future."

About Mars Express
Mars Express is a Mars exploration mission of the European Space Agency and the first planetary mission attempted by the agency. "Express" originally referred to the speed and efficiency with which the spacecraft was designed and built. However "express" also describes the spacecraft's relatively short interplanetary voyage, a result of being launched when the orbits of Earth and Mars brought them closer than they had been in about 60,000 years.

Mars Express consists of two parts, the Mars Express Orbiter and the Beagle 2, a lander designed to perform exobiology and geochemistry research. Although the lander failed to land safely on the Martian surface, the Orbiter has been successfully performing scientific measurements since Early 2004, namely, high-resolution imaging and mineralogical mapping of the surface, radar sounding of the subsurface structure down to the permafrost, precise determination of the atmospheric circulation and composition, and study of the interaction of the atmosphere with the interplanetary medium.

Due to the valuable science return and the highly flexible mission profile that Mars Express has been granted two consecutive mission extensions until (at least) May 2009.

Some of the instruments on the orbiter, including the camera systems and some spectrometers, reuse designs from the failed launch of the Russian Mars 96 mission in 1996 (European countries had provided much of the instrumentation and financing for that unsuccessful mission). The basic design of Mars Express is based on ESA's Rosetta mission, on which considerable sum was spent on development. The same design was also used for the Venus Express mission in order to increase reliability and reduce development cost and time.

The Mars Express mission is dedicated to the orbital (and originally in-situ) study of the interior, subsurface, surface and atmosphere, and environment of the planet Mars. The scientific objectives of the Mars Express mission represent an attempt to fulfil in part the lost scientific goals of the Russian Mars-96 mission, complemented by exobiology research with Beagle-2. Mars exploration is crucial for a better understanding of the Earth from the perspective of comparative planetology.

The spacecraft originally carried seven scientific instruments, a small lander, a lander relay and a Visual Monitoring Camera, all designed to contribute to solving the mystery of Mars' missing water. All of the instruments take measurements of the surface, atmosphere and interplanetary media, from the main spacecraft in polar orbit, which will allow it to gradually cover the whole planet. The overall Mars Express budget excluding the lander is €150 million (roughly US$185 million).

In the years preceding the launch of a spacecraft numerous teams of experts distributed over the contributing companies and organisations prepared the space and ground segments. Each of these teams focussed on the area of its responsibility and interfacing as required. A major additional requirement raised for the Launch and Early Orbit Phase (LEOP) and all critical operational phases was that it was not enough merely to interface; the teams had to be integrated into one Mission Control Team. All the different experts had to work together in an operational environment and the interaction and interfaces between all elements of the system (software, hardware and human) had to run smoothly for this to happen:
The flight operations procedures had to be written and validated down to the smallest detail;
The control system had to be validated;
System Validation Tests (SVTs) with the satellite had to be performed to demonstrate the correct interfacing of the ground and space segments.
Mission Readiness Test with the Ground Stations had to be performed;
A Simulations Campaign was run.

Pictures Overview
In figure 1, Mars Express in orbit around Mars

In figure 2, MEXAR2 in action

In figure 3, ESA's Perth station communicates with Mars Express

In figure 4, ExoMars rover - artist's concept