Mission to Ganymede more tricky than expected
The mission to Ganymede, now better known by the simple name of “Ganymede Lander”, is the latest reincarnation of Russia's contribution to the Laplas project, promoted by the European Space Agency (ESA) in the early 2000s. With Laplas becoming the single-spacecraft project JUICE (JUpiter ICy moon Explorer, until christened officially), Russian plans have also undergone major changes, although their main objective, sending a lander to Jupiter's biggest moon, remained intact. The initial aim was to explore Europa, a smaller Jovian moon, where there is an ocean of liquid water beneath its frozen surface (around 10 km thick) and is therefore considered a good prospect for the exploration of habitable conditions.
Ganymede also holds liquid water, but much deeper, under an icy crust of around 130–150 km. On the other hand, this moon is farther from Jupiter with less radiation than Europa, putting spacecraft at a much lower risk.
However, the main argument for shifting to Ganymede was that the European mission now no longer plans to stay near Europa long enough to provide the high resolution images needed to select a landing site. It is supposed now that the JUICE orbiting spacecraft will provide the Russian lander with preliminary reconnaissance data and perhaps act as a communication relay station for data sent between Ganymede and Earth.
Hence, the current scenario is that the European mission is developing independently while Russia's landing spacecraft has its own scientific payload and objectives. As the success of the landing relies on many technical issues closely concerned with JUICE, the Russian equipment and goals must be taken into account from the start when designing the eventual lander.
A more detailed mission scenario was presented by Maxim Martynov, deputy general designer of the S.A. Lavochkin Association and head of the design bureau. Following the “play safe” rule, it is supposed that Russia will send two spacecraft to Ganymede, a lander and a small additional orbiter to secure the landing site as a back-up option to information from JUICE. Even though launched simultaneously from a Proton launcher, they will arrive separately. After reconnaissance and remote studies of the moon, the lander will be delivered to the surface to begin its studies. The start is planned for 2022–23 with the completion in 2029–30 (JUICE is currently scheduled for 2022) and subsequent arrival on Ganymede within a few months.
The current status of the mission in Russia's space program is protected by governmental approval. The project was included in the Federal Space Program in force until 2015 and will be recommended for the next program valid from 2016 to 2025. According to Roscosmos representatives actual funding begins in 2014.
However, the success of the mission does not depend on solely on funding. Close ties with the European project impose additional constraints both on scheduling the mission and its design. For instance, Russian designers will have to maintain the radio frequencies used by the JUICE project to ensure the systems are compatible, as work near Ganymede requires accurate planning of the timeline. And, last but not least, even though scientific goals for the mission are independent, the synergy might just be beneficial to both sides. This issue however is still a subject for further discussion.
While European experts have already chosen scientific instruments to be installed on the spacecraft, the Russian project is still in its very early stages. The Ganymede lander is supposed to be an international project as well, but actual instrumentation proposals have yet to be announced. Then, even before they are chosen, the mission team will have to limit the number of scientific tasks the lander pursues. Essentially the entire plan is still very much prone to change.
Then, there is ExoMars, another joint venture between Europe and Russia, to be launched betweem 2016 and 2018. Its performance and outcome will inevitably influence the next planetary project, and lead time before heading for Mars is quite short. It seems then that the Russian leap for Ganymede will actually begin long before 2022.