WASHINGTON — Sweden signed the Artemis Accords outlining best practices for responsible space exploration April 16, the second European country in as many days to join.

NASA and the Swedish government announced that Sweden signed the accords in a ceremony at government offices in Stockholm. Mats Persson, Sweden’s minister for education and research, signed the accords alongside the U.S. ambassador to Sweden, Erik D. Ramanathan.

“By joining the Artemis Accords, Sweden strengthens its strategic space partnership with the U.S. on space covering areas such as Swedish space research and the space industry, which in turn also strengthens Sweden’s total defense capability,” Persson said in a statement.

Sweden is the 38th country to sign the accords and the second in as many days, after Switzerland signed on April 15 in a ceremony at NASA Headquarters. With Sweden’s accession, 14 of 22 full members of the European Space Agency have joined, along with 13 of 27 members of the European Union.

“Our nations have worked together to discover new secrets in our Solar System, and now, we welcome you to a global coalition that is committed to exploring the heavens openly, transparently, responsibly and in peace,” NASA Administrator Bill Nelson said in a statement. “The United States and Sweden share the same bedrock principles, and we’re excited to expand these principles to the cosmos.”

The Artemis Accords started with eight countries, including the United States, in 2020, and has grown steadily since then. The document outlines best practices intended to implement provisions of the 1967 Outer Space Treaty and other international agreements, as well as in other areas such as use of space resources and sharing of scientific data.

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...