Ever more countries are doing scientific research in space, or want to. In the past decade, China and India have joined the seasoned players — Russia, the United States, Europe and Japan1,2,3. And Turkey, South Korea, Saudi Arabia and the United Arab Emirates have expressed interest in joining space-science and deep-space missions.
Since 2007, China has launched two lunar orbiters and a lander. In 2019, it plans to send another that will bring Moon rocks back to Earth. In 2014, India’s Mars Orbiter Mission reached the red planet. In five years’ time, the Chinese Academy of Sciences and the European Space Agency (ESA) will jointly launch the Solar wind Magnetosphere Ionosphere Link Explorer (SMILE) to study interactions between Earth’s magnetosphere and the solar wind.
Why the growing interest? Space science is an engine of fundamental research and technology development. It also inspires the public and boosts national pride. These different aims can sometimes create tension.
During our years of leading space agencies, we have witnessed many ups and downs in the management of science missions. Scientific goals can get lost among the host of other practical and political concerns of a national or regional space programme. Inefficient management extends costs and ultimately fails to deliver the scientific breakthroughs that such programmes promise.
In our view, to get the most from space-science programmes — in terms of impacts on research and reputation — government agencies and institutions need to choose, manage and assess missions in ways that optimize the scientific outputs. As heads of space-science agencies and institutes from around the world gather at a forum next week in Beijing to identify principles for maximizing returns on such missions, we call on them to put science first.
Let scientists lead
National space-science budgets are, on average, less than 0.02% of gross domestic product4. The number of proposals will always exceed what can be funded.
Mission concepts should be suggested ‘bottom-up’ through a process led by scientists, rather than being decided by government authorities from the top down. The end-users are best placed to exploit the data and publish results.
For example, satellites in NASA’s medium-class explorer series have been suggested by and developed under the leadership of scientists. They have an impressive record. The Swift Gamma-Ray Burst Mission, for instance, has discovered around 100 cosmic γ-ray sources each year since 2004. It has generated up to 300 papers a year, including the first measurement of γ-rays coming from a source of gravitational waves, published last month5.
If a space agency takes the lead on designing a mission, scientists often simply ‘piggy-back’ instruments onto it. Researchers then have little responsibility for coordinating systems on board or for collaborating with other international projects, resulting in fewer scientific outputs. Appointing a principal investigator after the mission is selected or blueprinted might add leadership, but risks blurring the mission’s direction and diluting its output.
That said, scientists should not overstep their roles. When researchers, rather than the government, apportion budgets, costs often escalate to the detriment of other missions and the overall balance of a space programme.
Steps to success
Mission proposals should be solicited through two steps. Agency managers should first assess options with the research community to reach a consensus on which scientific frontiers are most likely to yield major breakthroughs. Agencies should then issue a formal ‘announcement of opportunity’ focused on these frontiers.
Government agencies should establish a process to enable the scientific community to agree on the most promising strategic directions for space science. Good examples include: the decadal surveys organized by the US National Academy of Sciences; ESA’s Horizon 2000 and Cosmic Vision 20-year plans; and China’s study on the future space-science programme, organized by the National Space Science Center of the Chinese Academy of Sciences6. These solicit input from across the research community and hold workshops to agree on priorities. Frontier areas identified in this way include: extraterrestrial planet searches by the United States, measurements of gravitational waves in space by ESA and dark-matter exploration by China.
Once proposals are received, they must be reviewed. Agencies should appoint a committee of space scientists with expertise in relevant areas to evaluate them. Care must be taken to avoid conflicts of interest that arise when scientists both initiate and judge ideas. The powerful voice of a large, established team could drown out a smaller group’s more innovative idea, for instance.
Proposals should be assessed against two criteria: impact and involvement. First, reviewers should determine whether the mission will uncover new knowledge about a key scientific frontier; make a broader breakthrough in human understanding of the Universe and nature; or overturn, expand or generate fundamental scientific theories. Second, they should ask whether it will involve a large number of participants from national or international scientific communities, thus promoting the community development and generating a wide range of publications.
Review and reflect
The most promising missions would meet one or, ideally, both criteria. For example, the Chinese Academy of Sciences’ Dark Matter Particle Explorer (DAMPE, or Wukong), launched in 2015, aims to explain the nature of dark matter by detecting γ-rays, electrons and cosmic-ray ions and was developed in collaboration with Swiss and Italian scientists. ESA’s Cluster II mission to monitor Earth’s magnetosphere involves more than 1,000 international researchers who analyse data from its 4 spacecraft, each of which carries 11 instruments.
Finally, a mission must be evaluated against the criteria that led to its selection. Managers should assess whether it has produced the expected breakthrough, even if it has yielded only a few high-impact papers. For example, the Quantum Experiments at Space Scale (QUESS, or Micius) satellite was launched in 2016 to test quantum encryption and teleportation technologies over long distances7. It is already considered a success on the basis of three papers in the journals Nature8,9 and Science7. Where collaboration is the main objective, more publications might be desirable. For example, the Hubble Space Telescope has generated some 10,000 papers over the past 27 years, as well as many breakthroughs.
Scientists and agencies should foster closer relationships and management strategies that put good science first. Preserving the fairness of selection and evaluation procedures and mediating relations across the board offer the best guarantee of a successful space-science mission.
Nature 551, 435-436 (2017)