NASA is working with SpaceX to develop its Starship human landing system (HLS) for use during the Artemis III and Artemis IV missions to land American astronauts near the South Pole of the Moon. The Starship HLS will be powered by two variants of the company’s Raptor engines—one optimized to operate in atmospheric pressure at sea-level and one optimized to operate in space, or in a vacuum, where there is no atmosphere.
Last month, SpaceX demonstrated a vacuum-optimized Raptor’s performance through a test that successfully confirmed the engine can be started in the extreme cold conditions resulting from extended time in space. One challenge that differentiates Artemis missions from those in low Earth orbit is that the landers may sit in space without firing for an extended period of time, causing the temperature of the hardware to drop to a level below what they would experience on a much shorter low Earth orbit mission.
One of the first testing milestones SpaceX completed under its Artemis III contract in Nov. 2021 was also an engine test, demonstrating Raptor’s capability to perform a critical phase of landing on the Moon. In a 281-second-long test firing, Raptor demonstrated the powered descent portion of the mission, when the Starship HLS leaves its orbit over the lunar surface and begins its descent to the Moon’s surface to land. The test had two goals: to show Raptor’s ability to change the level of engine power over time, known as its throttle profile, and for the engine to burn the full length of time of the powered descent phase. The successful test provided NASA with early confidence in the company’s engine development.
Testing critical technologies and hardware under simulated and actual flight conditions is key for the development of Artemis Moon landers. These tests provide early and mission-like validation of the systems necessary for carrying astronauts to and from the lunar surface. Data reviews following these tests provide NASA with continually increasing confidence in U.S. industry’s readiness for the mission. SpaceX’s Raptor engines will next be put to the test during the company’s second integrated flight test of Starship and Super Heavy.
With the success of NASA’s Artemis I launch, the previously unexplored shadowy regions near the lunar South Pole where Artemis astronauts will land in 2025, are more within our reach than ever before.
One instrument that will support these future lunar exploration efforts is a hypersensitive optical camera called ShadowCam. ShadowCam is one of six instruments on board the Korea Aerospace Research Institute (KARI)’s Korea Pathfinder Lunar Orbiter, known as Danuri, which launched in August 2022 and entered lunar orbit last December.
Previous cameras in lunar orbit were designed to acquire images of sunlit surfaces. Developed by Malin Space Science Systems and Arizona State University, ShadowCam’s primary function is to collect images within permanently shadowed regions near the lunar poles. These areas never receive direct sunlight and are thought to contain water ice – a significant resource for exploration that can be used as fuel or oxygen and for other habitation applications.
Building on cameras developed for NASA’s Lunar Reconnaissance Orbiter, ShadowCam is 200 times more light-sensitive and is therefore able to capture detailed images within permanently shadowed regions – even in the absence of direct light – by using the light that is reflected off nearby geologic features such as mountains or the walls of craters.
In addition to mapping the light reflected by permanently shadowed regions to search for evidence of ice deposits, ShadowCam will also observe seasonal changes and measure the terrain inside the craters, all in service of science and future lunar exploration efforts. The high-resolution images could help scientists learn more about how the Moon has evolved, how water is trapped and preserved in permanently shadowed regions, and could help inform site selection and exploration planning for Artemis missions.
Since Danuri entered lunar orbit, ShadowCam has been in an operational checkout period, during which it has been collecting dozens of images of the lunar polar regions, including an image of Shackleton Crater, to calibrate and test its functionality. Following this checkout period, which will conclude later this month, ShadowCam will start its campaign to capture images of shadowed terrain as Danuri routinely passes over them during the planned mission of 11 months.