WASHINGTON — The US space agency (NASA) has formally outlined its $28bn plan to return to the Moon by 2024. As part of a program called Artemis, NASA will send a man and a woman to the lunar surface in the first landing with humans since 1972. But the agency"s timeline is contingent on Congress releasing $3.2billion for building a landing system. Astronauts will travel in an Apollo-like capsule called Orion that will launch on a powerful rocket called the Space Launch System (SLS). “With bipartisan support from Congress, our 21st-century push to the Moon is well within America’s reach,” said NASA Administrator Jim Bridenstine in a press release. “As we’ve solidified more of our exploration plans in recent months, we’ve continued to refine our budget and architecture. We’re going back to the Moon for scientific discovery, economic benefits, and inspiration for a new generation of explorers. As we build up a sustainable presence, we’re also building momentum toward those first human steps on the Red Planet.” In its formal plan, NASA captures Artemis" progress to date, identifying the key science, technology, and human missions, as well as the commercial and international partnerships that will ensure we continue to lead in exploration and achieve our ambitious goal to land astronauts on the Moon. The SLS and the Orion spacecraft are closer than ever to their first integrated launch. The spacecraft is complete while the core stage and its attached four engines are undergoing a final series of tests that will culminate in a critical hot fire test this fall. Following a successful hot-fire test, the core stage will be shipped to the agency’s Kennedy Space Center in Florida for integration with the spacecraft. NASA will launch an SLS and an Orion together on two flight tests around the Moon to check performance, life support, and communication capabilities. The first mission — known as Artemis I — is on track for 2021 without astronauts, and Artemis II will fly with crew in 2023. In the Phase 1 plan, NASA notes additional details about conducting a new test during the Artemis II mission — a proximity operations demonstration. Shortly after Orion separates from the interim cryogenic propulsion stage, astronauts will manually pilot Orion as they approach and back away from the stage. This demonstration will assess Orion’s handling qualities and related hardware and software to provide performance data and operational experience that cannot be readily gained on the ground in preparation for rendezvous, proximity operations, and docking, as well as undocking operations in lunar orbit beginning on Artemis III. While preparing for and carrying out these flight test missions, NASA already will be back on the Moon robotically — using commercial delivery services to send dozens of new science investigations and technology demonstrations to the Moon twice per year beginning in 2021.