This has been an exciting decade for lunar exploration, but it hasn’t been without its setbacks.
AAPG EXPLORER provided an extensive overview of NASA’s Artemis “Return to the Moon” initiative in July 2022, then covered the Artemis I uncrewed flight test in December, which saw NASA’s powerful Space Launch System rocket, carrying the Orion spacecraft, take off the previous month. The Artemis I flight involved a lunar flyby, followed by entry into a distant retrograde orbit for six days, and a second lunar flyby on Dec. 5. The Orion spacecraft re-entered Earth’s atmosphere at 25,000 miles per hour using an ablative heat shield evolved from Apollo command module technology. It safely splashed down in the Pacific Ocean on Dec. 11, 2022.
The extent of erosion of the heat shield has raised concerns, though NASA says there was still a safety margin in the heat shield before the capsule would have been in danger of a hull breach.
Due to the agency’s commitment to crew safety, NASA officials announced a revised schedule for the Artemis lunar program at a news conference last month. The subsequent missions are expected to be delayed by approximately one year each, reflecting the extensive work required before astronauts can undertake lunar missions in the latter part of this decade.
New Mission Schedule
NASA Administrator Bill Nelson, Associate Administrator Jim Free, and SpaceX VP Jessica Jensen outlined the new mission dates:
- February 2024: SpaceX Starship Orbital Test Flight 3 is expected, pending FAA license. This flight might include an internal propellant transfer leading up to on-orbit ship-to-ship propellant transfer demonstration next year.
- 2025: An uncrewed Starship Human Landing System lunar landing demonstration is planned. Starship HLS on-orbit refueling will require about 10 tanker flights to prepare HLS for leaving Earth orbit for a moon landing. Starship holds 1,200 metric tons of propellant fully loaded. A tanker Starship will deliver about 120 metric tons of propellant payload to orbit.
- September 2025: Artemis II’s first crew flight is planned for a trip around the moon and back in a free-return trajectory.
- September 2026: Artemis III’s first crewed lunar landing is planned, with two astronauts descending to the surface in SpaceX’s Starship lander. Before Artemis III, SpaceX will need to fly dozens of reusable Starship missions without a crew.
- September 2028: Artemis IV’s second crewed lunar landing mission is planned, which will be the first flight using an upgraded version of the Space Launch System rocket. This mission will include a lunar landing in Starship.
Improvements Under Way
Acknowledging the complexity of the Artemis II mission, NASA Moon to Mars program Deputy Administrator Amit Kshatriya identified three key areas of focus.
The first pertains to the unexpected liberation of heat-shield pieces during Artemis I’s return, prompting an extensive assessment to identify the root cause.
The second involves potential damage to Orion’s batteries within the launch abort system, which is being addressed with multiple solutions.
Lastly, a design flaw in motor-valve circuitry in components destined for Artemis III required replacements and currently poses a pacing issue for the September 2025 launch date.
Artemis III, involving a crewed lunar landing, presents a substantial increase in complexity. In addition to testing the SLS rocket and Orion spacecraft in Artemis II, the mission introduces the Starship lunar lander, new spacesuits and the coordination of rendezvous and docking in lunar orbit. Critical concerns include the development of SpaceX’s Starship, including its safety, fuel transfer capability in orbit, uncrewed lunar landing and launch from the lunar surface using cryogenic fuels. The proposed September 2026 schedule is deemed realistic, with NASA emphasizing industry support and contractual commitments while acknowledging inherent risks.
Peregrine One Mission
Robotic lunar missions will pave the way for Artemis crewed lunar missions.
The December 2023 issue of the EXPLORER reported on the Astrobotics VIPER robotic mission scheduled to launch in November 2024 carrying the VIPER robotic lunar rover to the moon’s south pole. It shares a similar NASA science payload as the Astrobotics Peregrine One Mission.
Peregrine One launched from Kennedy Space Center on Jan. 8, 2023, on the first flight of a Vulcan Centaur rocket. After the trans-lunar injection burn, the mission soon ran into problems.
Approximately seven hours post-launch, Astrobotic reported an issue, likely related to the propulsion system, preventing Peregrine from achieving a stable orientation facing the sun to charge batteries with its extended solar panels. An unplanned spacecraft maneuver was executed to reorient the solar panels toward the sun, overcoming an expected communication blackout and confirming the restoration of power generation. However, the problem was identified as a gradual propellant leak, necessitating continuous fuel consumption for stabilization. Astrobotic stated that the thrusters exceeded their anticipated service life cycles and the spacecraft could maintain a stable sun-pointing state for roughly 40 more hours before depleting fuel, leading to a loss of attitude control and power.
In a subsequent announcement, Astrobotic confirmed that Peregrine could no longer execute a moon landing but could remain operational as a spacecraft. Images from the spacecraft revealed damage to the multilayer insulation on its exterior, potentially caused by a valve that failed to fully close, resulting in the rupture of the oxidizer tank.
On mission day four, the propellant leak exhibited signs of tapering off, prompting Astrobotic to announce Peregrine’s extended survival beyond initial expectations. Despite the propulsion system challenge, the Astrobotic Mission Team diligently worked to stabilize the vehicle, activate all active science payloads and facilitate the collection of payload data. Despite missing the lunar landing objective, testing the science payloads served as a valuable rehearsal for the upcoming VIPER mission.
“This mission has already taught us so much and has given me great confidence that our next mission to the Moon will achieve a soft landing,” said Astrobotic CEO John Thornton.
Ultimately, the spacecraft reached a position allowing it to reach the Moon with trajectory corrections. However, six days into the mission, Astrobotic opted to redirect the spacecraft for controlled reentry into Earth’s atmosphere on January 18 into the Pacific Ocean east of Australia, mitigating the risk of contributing to space debris.