How are space agencies coordinating their science missions internationally?

Question

Is there any coordination between governmental space agencies in order to achieve complementary science goals with interplanetary and other space missions? If so, is this done somewhat informally through the academic world, or is there some formal institution for this?

My impression is that missions from different governments sometimes overlap suboptimally. For example, are ESA's Mars Express orbiter and the ISRO's Mars Orbiter Mission really complementary with two NASA orbiters already there? Is the ESA's ExoMars Trace Gas Orbiter to be launched in 2016 really an added value to the NASA's MAVEN (Mars Atmosphere and Volatile EvolutioN Mission) launched in 2013? Would NASA have considered doing those missions on its own if no one else had? Do they fit rationally into the grand plan of Mars exploration? ESA has also followed NASA to Venus and Mercury. And now NASA considers to follow ESA's JUICE mission to Jupiter's moons.

NASA and ESA both have fairly diversified mission portfolios. But taken together, they seem to overlap a lot. JAXA's asteroid and comet missions, however, I think can fit with those of NASA and ESA because of the variety of the targets and big differences in mission profiles (Hayabusa, Dawn, Rosetta). And Russia at least aims for the moons of Mars, rather than yet another Mars orbiter or rover.

Answer 1

There are a lot of angles to this question, which is probably why it has taken so long for this post to receive an answer. I'm going to try to break this down into a few different points:

1. The Title Question

There is no single forum for coordinating activities across all space agencies internationally, unless you count the United Nations Office for Outer Space Affairs. Its purpose is to facilitate intergovernmental discussions and the use of space technology by developing countries, so it doesn't really get into the realm of organizing an international space exploration strategy (until September 2016, see here).

2. Global Exploration Strategy

There does, however, exist a Global Exploration Strategy which is advanced by the 14 member agencies of the International Space Exploration Coordination Group (ISECG): ASI (the Italian space agency), CNES (the French space agency), CNSA (China National Space Administration), CSA (Canadian Space Agency), CSIRO (the Australian space agency), DLR (the German space agency), ESA, ISRO (Indian Space Research Organization), JAXA (Japan Aerospace Exploration Agency), KARI (Korea Aerospace Research Institute), NASA, NKAU (the Ukrainian space agency), Roscosmos, and the UK Space Agency. The Global Exploration Strategy was released in May 2007 and it identified the same need you are pointing to here, an international coordination mechanism. The ISECG was instituted to be that coordination mechanism.

The ISECG holds regular meetings to establish non-binding products and form working groups for collaboration.

3. Duplication Abounds

Since ISECG products are non-binding, each agency is still free to accomplish its own agenda. There is a strong drive in most states to develop science and technology internally to maintain a competitive advantage against other states. As such, you will see things like ISRO's MOM and China's Yutu, which though they have independent purposes, also serve as demonstrations of the national level of development.

4. Is the Duplication Worthless?

Really, though, there is so much data to be gathered and so much development to be done to exploration technology, that it would be hard to assess whether the duplication is really suboptimal. Also, space exploration is risky business. A little redundancy ensures that progress continues to be made.