This month the European Space Agency's Space Science Advisory Committee will make a recommendation on which large space mission, to launch in the early 2020s, should get the agency's backing.
Three candidate missions are being considered and have made their final submissions to the Committee.
The European Space Agency (ESA) will make its final decision in May on whether to give the go ahead for the recommended mission.
Large size missions are classified as "L-Class" by ESA under its "2015 - 2025 Cosmic Vision" which provides an overall strategy and direction for all of ESA's space missions.
ESA provides funding of in the region of €700million (U.S. $930m) for L-Class missions. Member states can top up the overall mission budget.
The chosen mission would launch in the early 2020s.
The stakes are especially high because all the teams, who have been formulating their proposals for several years, have been forced to make last-minute revisions after the U.S. space agency, NASA, decided last year to cease its participation in any of the proposed missions.
It meant that the teams had to re-work their proposals to meet much tighter budgetary constraints.
The advisory committee is expected to deliver a recommendation to ESA in the coming days when it will be passed on to the agency’s Science Programme Committee for a final decision in May.
The contenders for the large class mission are:
ATHENA (Advanced Telescope for High ENergy Astrophysics)
With a focal length of 12 metres, this would be the biggest X-ray telescope ever built.
The telescope’s primary mission would be to study the dynamic environment that exists close to a black hole. It would also seek to examine how supermassive black holes – of the type thought to exist in the heart of every galaxy – are formed.
ATHENA would be equipped with two X-ray telescopes.
The craft’s size would push the limits of the Ariane 5 rocket that would launch the telescope into space sometime around 2022. The mission would last five years.
ATHENA has been billed as being a complimentary mission to NASA’s James Webb Space Telescope (pictured). Credit: NASA
NGO (New Gravitational wave Observatory)
This mission’s goal would be to detect gravitational waves (ripples in space and time). Gravitational waves are thought to be very weak and their effects very small, but they are an important part of Einstein’s Theory of Relativity.
The mission - formerly called 'Lisa' - would consist of three satellites – a mothership and two daughters – separated by a million kilometre gap.
Lasers running between the three craft would be used to detect the smallest changes in the relative position of the daughter craft.
Each satellite would house a 4cm gold-platinum alloy cube that would float freely within the craft and act as a reflector for the laser beams.
Any disturbances in the measurements would indicate the arrival of a gravitational wave emitted by a extreme events – such as the collision of supermassive black holes.
The mission would launch no earlier than 2022 and would last six years.
By studying gravity waves, NGO will put Einstein’s Theory of Relativity to the test. Credit: ESA
JUICE (JUpiter ICy Moons Explorer)
This mission would be sent to study the icy moons of the gas giant, Jupiter.
It envisages a five-tonne, instrument-laden satellite that would orbit the Jovian moons Europa, Ganymede and Callisto.
JUICE was re-formulated from the "EJSM/Laplace" proposal after NASA withdrew from the mission. ESA had been planning to provide the Jupiter Ganymede Orbiter whilst NASA would have provided the Jupiter Europa Orbiter. It is now proposed as a single spacecraft that would study the three moons, examining whether the moons support life and understanding more about the liquid ocean under Ganymede's icy surface.
The craft would also seek to uncover the conditions under which the Jovian system was formed and how Jupiter works. It would launch no earlier than 2022 for arrival at Jupiter in 2030. The mission would spend 4 years in orbit.
JUICE would study Jupiter's moons Ganymede, Europa and Callisto. Credit: ESA