ESA Science & Technology - ESA confirms Rosetta's new target but identifies financial challenge for the mission

Since January, three options have been thoroughly analysed: the first to fly to the original target, Comet Wirtanen, using a Russian Proton rocket, the second and third to fly to Comet Churyumov-Gerasimenko but launching a year apart, using either an Ariane-5 hybrid or a Proton launcher.

As reported earlier, the choice of a new comet has required intensive efforts, including observations by telescopes such as the Hubble Space Telescope and the ESO Very Large Telescope to ensure we know as much as we can about the new target. Ultimately, Wirtanen had to be rejected because of several reasons, the most important of which was the danger in moving the fully fuelled spacecraft from Kourou to Baikonur (offloading the fuel would pose an even greater risk by causing structural problems in the fuel tanks).

Therefore, the February 2004 launch to Churyumov-Gerasimenko has been chosen. The February 2005 launch to the same comet will now be investigated as a back-up plan. Rendezvous with the comet is expected in November 2014. At present, scientific teams are investigating orbits that could allow an earlier rendezvous and also perform a number of asteroid fly-bys en route.

Despite the progress and the optimism that it brought, the kick-off of the new mission now depends on the fast solution to a new emergency: cash. The cost of the overall delays imposed by the grounding of Ariane is estimated to be 80 million Euros. During January 2003, when the decision to delay Rosetta was taken, ESA Director of Science Prof. David Southwood was confident that this could be absorbed by the science budget. However, since then a number of other unexpected economic obligations have arisen. "If the extra funding required for Rosetta was the only tab on the table, the ESA Science Directorate could have absorbed the cost," says Prof. Southwood, "Unfortunately, we have to face a number of other financial challenges."

These include the need to inject 70 million Euros into the development of instruments for two missions, Herschel and Planck, to prevent their industrial development from being derailed. Also, while the programme worked to get cheaper bids from industry, the depressed satellite market at this time has required up-front payments. In this year, it turns out that costs of 50 million Euros have appeared earlier than planned. Recalling that ESA overall should bolster a European space industry, particularly in tough times, Southwood said, "One does not regret the policy so much as the timing. The demand has come at the worst possible time."

Ever since the Edinburgh ESA Ministerial Council meeting during 2001, the ESA Science Directorate has operated its ambitious programme on the tightest of budgets that allow little room for unexpected emergencies. The rules of ESA preclude Southwood from borrowing money and he is adamant that cancelling another mission to save Rosetta is not an option. "In any event, cancelling a different mission won't give me the money this year," he says.

As a result, the money to save Rosetta is to be found through some immediate financial flexibility at Agency level. "I am not asking for more money overall, but for help in cash flow. We in ESA are sure that we will find the necessary sensitivity, understanding and, ultimately, solidarity from the Council. Europe paved the way to comet science with Giotto and it is a matter of great pride that the ultimate comet explorer will be European." Options for resolving the financial issue will be proposed to the ESA Council in June this year.

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