President-elect Donald Trump has declared his support for NASA's exploration mission and its human space-flight programme in particular. As a professor of planetary and space sciences, I am concerned that his opinion may be coloured by the flag-waving opportunities that these present, and that he could be interested in territorial rather than global benefit (see also Nature http://doi.org/bs58; 2016).

I am also concerned about statements he has made regarding public–private partnerships, and increasing the role of the private sector in space exploration. As a businessman, he may decide to sell off some of NASA's assets to the private sector, without sufficient thought for safety and governance.

In my view, the international collaborative efforts that are currently in place are the correct way to progress. More-stringent visa regulations could make it harder for UK researchers to take up fellowships and research positions in the United States, hampering our partnerships in space missions and restricting the sharing of data and technology.