Last month, the new Trump administration submitted a new blueprint for NASA's budget calling for a net overall increase. Although on a program-by-program basis there were winners and losers, the overall increase was seen to benefit NASA's core mission competencies as far as space exploration while reducing government redundancies. Over the past several years the Obama administration had repeatedly proposed cuts for NASA, which were then overridden by Congress managing to maintain NASA funding.
There were many highlights in the new budget. An increase in unmanned planetary science pleased the Planetary Society. In general, though, I'll focus on manned space exploration.
The Obama administration's proposed Asteroid Redirect Mission (ARM) has been canceled. The mission had been proposed following Obama's cancellation of the George W. Bush administration's Constellation Program. Constellation's objectives included returning men to the surface of the moon in preparation of a future visit to the planet Mars. ARM involved development of an unmanned probe that would visit an asteroid, bag a big boulder, then place it in orbit around the moon where astronauts would visit and handle the rock. When originally proposed, ARM was advertised as an alternative to the Constellation program as a way for astronauts to go beyond Earth's orbit in preparation of a future Mars mission. But plans did not include visiting the asteroid in situ; sending astronauts into lunar orbit has been done before. Plus ARM contained no provision for developing a landing craft which would be vital for future landings on either the moon or Mars.
The Space Launch System (SLS), Obama's eventual replacement program for Constellation, got a boost in the Trump budget. SLS involves development of a new heavy lift booster rocket and an Orion crew capsule plus its European-developed service module. Its immediate plans will still include two launches. In 2018, Exploration Mission 1 (EM-1) calls for sending an unmanned "block 1" Orion spacecraft into lunar orbit and then back to Earth. EM-2 in 2021 would send a human crew in a "block 2" capsule to loop around the moon without stopping to orbit. Trump is interested in pushing the crewed mission forward and has requested a study for doing so.
Outside of NASA, new commercial spacecraft are being developed for ferrying crews to the International Space Station (ISS). Currently, the United States has outsourced taxi services to Russia and its manned Soyuz spacecraft. Boeing has a capsule currently under development called Starliner. SpaceX's Dragon spacecraft has been used for resupplying the ISS. A man rated version of Dragon is under development. Starliner and Dragon service are both expected to begin carrying humans no earlier than 2018.
SpaceX recently made an announcement that it also plans to send two anonymous tourists that can afford it on a trip around the moon, perhaps as early as 2018. It would do a loop around the moon on a return trajectory similar to NASA's planned EM-2 Orion mission.
NASA's goal of sending humans to Mars in the 2030s remains unchanged. The first trip will likely be an orbital reconnaissance mission without landing.
Last year, China discussed launching its first manned lunar landing mission by 2036. This year China says it is developing a new spacecraft for future missions both in Earth orbit and for landing on the moon.
Last year Russia announced a scheme to develop a nuclear-powered rocket to send humans on fast journeys to Mars. A timeline for the plan wasn't clear. Russia has also discussed building a lunar base by 2030.
If these plans continue the US will go from having no operational vehicles for sending men into space to having three: Orion, Dragon and Starliner.