Barack Obama (2009-2017)
In 2009, President Barack Obama called for a review of American human spaceflight plans by an expert panel, which came to be known as the Augustine Commission (not to be confused with the similarly named report President George H.W. Bush ordered two decades earlier).
A year later, Obama announced his administration's space policy, which represented a radical departure from the path NASA had been on. The new policy canceled George W. Bush's Constellation program, which the Augustine Commission had found to be significantly behind schedule and over budget. (Obama did support continued development of the Orion spacecraft for use as a possible escape vehicle at the space station, however.)
In place of Constellation, Obama's policy directed NASA to focus on getting humans to an asteroid by 2025 and then on to Mars by the mid-2030s. This entails, in part, developing a new heavy-lift rocket, with design completion desired by 2015.
The new policy also seeks to jump-start commercial spaceflight capabilitites. Obama's plan relies on Russian Soyuz vehicles to ferry NASA astronauts to the space station in the short term after the space shuttles retire in 2011.
But over the long haul, Obama wants this burden shouldered by private American spaceships that have yet to be built. So Obama promised NASA an extra $6 billion over five years, which the agency would use to help companies develop these new craft.
Donald Trump (2017-present)
President Donald Trump has directed NASA to return astronauts to the moon in preparation for future crewed missions to Mars and other locations across our solar system. The directive, which has no set timetable of funding, was unveiled Dec. 11, 2017 when Trump signed Space Policy Directive 1.
NASA officials said early funding estimates for the new directive, which would rely on the agency's Orion crew capsule and Space Launch System rocket, as well as commercial and international partnerships, will be included in the space agency's 2019 budget request.