WASHINGTON — NASA plans to make oxygen, a central ingredient of rocket fuel, on Mars early in the next decade.

Space agency officials on Thursday unveiled seven instruments they plan to put on a Martian rover that would launch in 2020, including two devices aimed at bigger future Mars missions.

The $1.9 billion rover will include an experiment that will turn carbon dioxide in the Martian atmosphere into oxygen. William H. Gerstenmaier, an associate administrator for NASA, said the oxygen could then be used to make rocket fuel and for future astronauts to breathe. Taking fuel to Mars for return flights would be heavy and expensive.

The device, named Moxie, operates like an engine but in reverse, said Michael Hecht, the scientist at the Massachusetts Institute of Technology who is running the test project. It will make about three-quarters of an ounce of oxygen an hour.