Nasa should focus its efforts on a solar-powered rover mission to Mars rather than human spaceflight in the coming decade, but only if costs can be slashed, a science panel said.
The recommendation was part of a report by the National Research Council urging a series of planetary missions “that could provide a steady stream of important new discoveries about the solar system” from 2013 to 2022.
The report comes as Nasa faces scrutiny from lawmakers over its proposed 2012 budget and pressure from the public to find a new way to transport astronauts into space once the three-decade old shuttle programme ends this year.
“The committee is concerned that, as demonstrated in the recent past, human spaceflight programs can cannibalise space science programs,” it said, urging budget firewalls between science-driven space missions and human spaceflight.
“Human exploration can provide important opportunities to advance science, but science is not the primary motivation,” it said.
“If the Apollo experience is an applicable guide, robotic missions to targets of interest will undoubtedly precede human landings.”
The Mars project, known formally as the Mars Astrobiology Explorer Cacher (MAX-C), aims to help scientists figure out if life ever existed on the red planet and would be a joint venture with the European Space Agency for launch in 2018.
“The martian surface preserves a record of earliest solar system history, on a planet with conditions that may have been similar to those on earth when life emerged,” the report said.
“It is now possible to select a site on Mars from which to collect samples that will address the question of whether the planet was ever an abode of life.”
But the current scope of the rover plans are too wide and must be narrowed to shave a billion from the costs, set by independent experts’ estimates at $3.5 billion, and “ensure that both agencies still benefit”.
The second priority should be exploring Jupiter’s icy moon Europa as a potentially livable environment, the Council said.
“This moon, with its probable vast subsurface ocean sandwiched between a potentially active silicate interior and a highly-dynamic surface ice shell, offers one of the most promising extraterrestrial habitable environments in our solar system and a plausible model for habitable environments outside it.”
There too, prohibitive costs associated with the mission must be cut back, otherwise “it would lead to an unacceptable programmatic imbalance, eliminating too many other important missions”, the report said. The projected cost of the Jupiter Europa Orbiter is $4.7 billion by fiscal year 2015.
“Therefore, while the committee recommends JEO as the second highest priority Flagship mission, close behind MAX-C, it should fly in the decade 2013-2022 only if changes to both the mission and the Nasa planetary budget make it affordable without eliminating any other recommended missions.”
The report was requested by Nasa and the National Science Foundation “to review the status of planetary science in the US and to develop a comprehensive strategy that will continue these advances in the coming decade”.