Lawmakers writing NASA’s budget want a cheaper upper stage for the SLS rocket

In a move that defies the Trump administration's intentions, Congress is rallying to support NASA's Space Launch System (SLS), the massive rocket crafted to return astronauts to the Moon. Recent spending bills progressing through both chambers of Congress have explicitly rejected the White House's proposal to phase out the SLS program after just two more launches. The House Appropriations Committee has released a draft budget that indicates a willingness to consider significant modifications to the SLS initiative. The upcoming SLS mission, Artemis II, is set to launch in early 2024, carrying a crew of four astronauts on a journey around the far side of the Moon. Following this, Artemis III aims to achieve a historic crewed lunar landing at the Moon's south pole, building on the success of the uncrewed Artemis I test flight conducted in 2022. While the Trump administration's official stance is to terminate the SLS program after Artemis III, along with the Orion crew capsule, it has also suggested scrapping the Gateway lunar mini-space station. Instead, the administration proposed relying on commercial entities for lunar transport, redirecting NASA's focus to Mars exploration. However, both House and Senate appropriations bills are working to ensure the continuation of the SLS, Orion, and Gateway programs. Notably, the House budget includes a directive for NASA to investigate more economical and efficient alternatives for a new upper stage for the SLS. Boeing, already responsible for constructing the core stages of the SLS, has been tasked with developing an Exploration Upper Stage intended for the Artemis IV mission. This new stage is designed to incorporate larger propellant tanks and feature four engines, a shift from the single-engine interim upper stage currently used for the first three SLS launches.