The European Space Agency (ESA) is being asked to approve a package of missions that includes a major project to Mercury and a significant part in the NASA-led Next Generation Space Telescope (NGST). The move is intended to meet the needs of space scientists across a range of disciplines.
Both projects received the backing of ESA's Space Science Advisory Committee (SSAC) last week, and are scheduled for launch in about 2009. The panel also approved a solar mission, the Solar Orbiter, and an astrometry mission, GAIA, both scheduled for launch around 2012.
If approved — as is widely expected — the mission to Mercury will be ESA's fifth major ‘cornerstone’ mission, with a budget of around 600 million euros ($514 million). It is known as Bepi Colombo, after the Italian space pioneer Giuseppe Colombo who in the 1960s worked out how to use the gravity fields of planets to ‘slingshot’ a spacecraft towards its destination, a technique used on NASA missions to Mercury in the 1970s.
Bepi Colombo will use a new solar- electric propulsion system. It will have a lander to investigate Mercury's surface and remote-sensing instruments to study the planet's surface and magnetosphere.
ESA will contribute around 150 million euros to the NGST — about 15% of its estimated total cost. This is comparable to ESA's involvement in the Hubble Space Telescope.
Bernard Seery, NGST's project manager at the the Goddard Space Flight Centre near Washington DC, says he is delighted but not surprised by the recommendation. “ESA and NASA have been working together on the development of the NGST concept since its inception,” he says.
The Canadian Space Agency will take a 5% stake in the NGST, and some European countries may increase their participation. Italy has offered to add a further ten million euros, to be handled by ESA, and the United Kingdom is believed to be negotiating a bilateral agreement with NASA.
As with Hubble, ESA will contribute to the spacecraft as well as its instruments. It is slated to provide the NGST's near-infrared multi-object spectrometer, an innovative apparatus that will allow about 100 celestial objects to be observed at once.
In juggling the interests of researchers working on the Solar System, astronomy and fundamental physics, the SSAC decided to recommend that GAIA — another cornerstone mission — be launched unusually soon after Bepi Colombo.
ESA's earlier astrometry mission, Hipparcos, completed its data collection in 1997, and ESA is keen to ensure that the groups analysing these data do not disperse before GAIA is developed. “A delay in its development would be a risk for the continuity of these groups,” says Jordi Torra, an astronomer at the University of Barcelona.
The SSAC recommended the Solar Orbiter as its third ‘flexible’ mission, rather than a Mars mission as some had predicted. This was partly out of concern that taking on Bepi Colombo on top of a number of other large missions — including Mars Express and the cornerstone mission to comet Rosetta, both due for launch in 2003 — might overstretch Europe's planetary scientists.
Also, the joint NASA/ESA mission to Saturn, Cassini–Huygens, launched in 1997, will reach its destination in 2004. “Research groups must be available to take on these projects,” says Giovanni Bignami, science director of the Italian Space Agency. “There is some concern that in planetary sciences they are getting saturated.”
The SSAC also recommended that ESA uses a future ‘flexible’ mission to participate in another planned NASA-led project to detect gravity waves. ESA's Space Policy Committee will decide formally on the new missions next month.
Additional reporting by Xavier Bosch, Barcelona.