Moon fly-by live coverage: Trump congratulates Artemis crew on successful mission so far – Nature
Former President Donald Trump extended congratulations to the crew of NASA's Artemis mission following its successful lunar fly-by. The uncrewed Orion spacecraft completed a critical maneuver around the Moon, marking a significant milestone in the agency's ambitious return to the lunar surface program. This achievement represents a pivotal step in America's renewed push for deep space exploration, laying the groundwork for future human missions.
Background: A New Era of Lunar Exploration Rooted in History
The Artemis program, NASA's ambitious initiative to return humans to the Moon, draws heavily on a rich legacy of space exploration while charting a new course for sustainable lunar presence and eventual Mars missions. Its origins can be traced through decades of shifting priorities, technological advancements, and evolving political landscapes.
Echoes of Apollo: The First Lunar Race
The initial human endeavor to reach the Moon, the Apollo program, was born out of the Cold War's Space Race between the United States and the Soviet Union. President John F. Kennedy's bold challenge in May 1961 to land a man on the Moon and return him safely to Earth before the decade was out galvanized the nation. Under the leadership of figures like Wernher von Braun, NASA developed the colossal Saturn V rocket, the Lunar Module, and the Command Module, pushing the boundaries of engineering and human capability.
On July 20, 1969, Apollo 11 achieved this monumental goal, with Neil Armstrong and Buzz Aldrin stepping onto the lunar surface while Michael Collins orbited above. This triumph was followed by five more successful lunar landings, concluding with Apollo 17 in December 1972. The Apollo program yielded invaluable scientific data, spurred technological innovation, and inspired a generation, but ultimately concluded due to budget constraints and a shift in national priorities towards reusable spacecraft and Earth-orbiting stations.
The Intervening Decades: Shifting Focus
Following Apollo, NASA's focus transitioned to the Space Shuttle program, which operated from 1981 to 2011. The Shuttles served as the primary vehicles for deploying satellites, conducting scientific research, and, crucially, constructing the International Space Station (ISS). The ISS, a testament to global collaboration, has maintained a continuous human presence in low-Earth orbit since November 2000, fostering international partnerships in space.
While the Shuttle and ISS programs were vital, deep space human exploration, particularly lunar missions, took a backseat. In 2004, President George W. Bush announced the Vision for Space Exploration (VSE), proposing a return to the Moon as a stepping stone to Mars. This led to the Constellation program, which aimed to develop new rockets (Ares I and Ares V) and a crew exploration vehicle (Orion). However, Constellation faced significant cost overruns and schedule delays. In 2010, the Obama administration canceled the program, citing budget issues and a lack of innovation, instead redirecting NASA's efforts towards a human mission to an asteroid and the development of a heavy-lift rocket and a multi-purpose crew vehicle for deep space.
Genesis of Artemis: A Return to the Moon
The current impetus for lunar return solidified under the Trump administration. In December 2017, President Donald Trump signed Space Policy Directive 1 (SPD-1), explicitly directing NASA to "lead an innovative and sustainable program of exploration with commercial and international partners to enable human expansion across the solar system and to bring new knowledge and opportunities back to Earth. Beginning with missions beyond low-Earth orbit, the United States will lead the return of humans to the Moon for long-term exploration and utilization, followed by human missions to Mars and other destinations."
This directive set the stage for the Artemis program, named after the Greek goddess, twin sister of Apollo, symbolizing a new era of inclusivity with the aim of landing the first woman and first person of color on the Moon. Under then-NASA Administrator Jim Bridenstine, the program's goals were articulated: to establish a sustainable human presence on and around the Moon, foster a lunar economy, and use the Moon as a proving ground for human missions to Mars. Artemis adopted a phased approach, beginning with uncrewed test flights (Artemis I), followed by crewed circumlunar missions (Artemis II), and culminating in human lunar landings (Artemis III).
The Space Launch System (SLS): Backbone of Artemis
The Space Launch System (SLS) is NASA's super heavy-lift expendable launch vehicle, designed to carry the Orion spacecraft and other payloads beyond low-Earth orbit. Its development is deeply intertwined with the canceled Constellation program and the Space Shuttle era.
The SLS Core Stage, standing 212 feet tall, is the largest rocket stage ever built by NASA. It is powered by four RS-25 engines, which are upgraded versions of the Space Shuttle Main Engines, burning liquid hydrogen and liquid oxygen to generate over 2 million pounds of thrust. The core stage is manufactured by Boeing at NASA's Michoud Assembly Facility in New Orleans, Louisiana, with Aerojet Rocketdyne supplying the RS-25 engines.
Flanking the Core Stage are two five-segment Solid Rocket Boosters (SRBs), provided by Northrop Grumman. These boosters, derived from the four-segment SRBs used on the Space Shuttle, provide over 75% of the total thrust during the first two minutes of flight. They burn solid propellant and are manufactured in Utah.
For the Artemis I mission, the SLS employed an Interim Cryogenic Propulsion Stage (ICPS), a modified Delta Cryogenic Second Stage (DCSS) from United Launch Alliance (ULA). This upper stage, powered by a single Aerojet Rocketdyne RL10 engine, performs the crucial Trans-Lunar Injection (TLI) burn to send Orion towards the Moon. Future, more powerful versions of SLS will feature an Exploration Upper Stage (EUS) with four RL10 engines, significantly increasing payload capacity for more complex missions.
The SLS program has faced considerable challenges, including significant cost overruns and schedule delays, leading to intense scrutiny from Congress and the public. However, its successful inaugural flight with Artemis I demonstrated its immense power and capability, validating years of engineering and manufacturing effort across numerous NASA centers and private contractors.
The Orion Multi-Purpose Crew Vehicle: Crew’s Home in Space
The Orion Multi-Purpose Crew Vehicle (MPCV) is the spacecraft designed to transport astronauts to deep space destinations. Its development began under the Constellation program as the Crew Exploration Vehicle (CEV) and has evolved into a highly capable vehicle.
The Crew Module (CM), built by Lockheed Martin, is designed to accommodate four astronauts. It features an advanced heat shield, made of Avcoat ablative material, capable of withstanding the extreme temperatures of high-speed re-entry into Earth's atmosphere. The CM also houses life support systems, navigation equipment, and parachutes for splashdown.
A critical international contribution to Orion is the European Service Module (ESM), provided by the European Space Agency (ESA) with Airbus Defence and Space as the prime contractor. The ESM provides propulsion, electrical power, thermal control, and essential life support elements like water and oxygen for the crew module. It incorporates a main engine (derived from the Space Shuttle's Orbital Maneuvering System engine) and 24 smaller thrusters. This collaboration underscores the international nature of the Artemis program.
Orion has undergone extensive testing, including the Exploration Flight Test-1 (EFT-1) in 2014, an uncrewed suborbital flight, and the Ascent Abort-2 (AA-2) test in 2019, which successfully demonstrated the launch abort system. The spacecraft is equipped with advanced radiation shielding and its mission profiles are carefully planned to minimize astronaut exposure to deep space radiation, a major concern for long-duration missions beyond Earth's protective magnetosphere.
Lunar Gateway: An Orbital Outpost
Integral to NASA's vision for a sustainable lunar presence is the Lunar Gateway, a small modular space station planned to orbit the Moon. The Gateway will serve as a multi-purpose outpost, providing a staging point for lunar landings, a science laboratory, and a communication relay.
The initial elements of the Gateway include the Power and Propulsion Element (PPE), being developed by Maxar Technologies, which will provide power, propulsion, and high-bandwidth communications. The Habitation and Logistics Outpost (HALO), developed by Northrop Grumman, will serve as the initial crew cabin and docking port.
The Gateway is designed for international and commercial collaboration, with ESA, JAXA, and the Canadian Space Agency (CSA) contributing modules and systems. Commercial partners are also expected to provide logistics and resupply services. The first elements of the Gateway are planned for launch in the mid-2020s, with assembly occurring in a Near Rectilinear Halo Orbit (NRHO) around the Moon, an orbit chosen for its stability and access to both the lunar surface and deep space.
Human Landing System (HLS): The Final Leg
The Human Landing System (HLS) is the critical component that will transport astronauts from lunar orbit to the Moon's surface and back to the Gateway or Orion. NASA initially solicited proposals from multiple commercial companies for the HLS development.
In April 2021, NASA controversially selected SpaceX's Starship HLS as the sole provider for the Artemis III landing, drawing protests from competing bidders like Blue Origin and Dynetics. SpaceX's Starship HLS design is a massive, fully reusable spacecraft that requires multiple in-orbit refueling missions in Earth orbit before it can travel to the Moon. Its large payload capacity promises to enable extensive surface operations.
Following the initial sole-source award, NASA announced a new program, "Sustained Lunar Development," to procure additional HLS services from other companies, aiming to foster competition and ensure redundant capabilities for future missions beyond Artemis III. This approach seeks to develop a robust commercial lunar ecosystem.
International Collaboration and the Artemis Accords
International collaboration is a cornerstone of the Artemis program, extending beyond hardware contributions to a shared framework for responsible lunar exploration. The Artemis Accords, launched by the U.S. in 2020, are a set of non-binding principles designed to govern civil space exploration and the peaceful use of the Moon and other celestial bodies.
Key principles of the Accords include transparency, interoperability of systems, emergency assistance, registration of space objects, release of scientific data, protection of heritage sites, and the safe disposal of debris. Crucially, the Accords also address the utilization of space resources (In-Situ Resource Utilization, or ISRU) and the creation of "safety zones" to prevent harmful interference, consistent with the Outer Space Treaty of 1967.
As of late 2023, more than 30 nations have signed the Artemis Accords, including the United Kingdom, Japan, Canada, Australia, Italy, the United Arab Emirates, and many others. These accords represent a U.S.-led effort to establish norms of behavior in space, particularly as more nations and commercial entities venture to the Moon, ensuring a peaceful and stable environment for long-term lunar presence.
Key Developments: Artemis I Mission Execution and Lunar Fly-by
The Artemis I mission, an uncrewed flight test of the Space Launch System (SLS) and the Orion spacecraft, represented the culmination of years of development, overcoming numerous technical and logistical hurdles. Its successful execution, particularly the lunar fly-by, provided critical data and validated the foundational elements of NASA's lunar return architecture.
The Path to Launch: Challenges and Preparations
The journey to the launch pad for Artemis I was fraught with challenges. The massive SLS rocket and Orion spacecraft underwent multiple "wet dress rehearsals" at Launch Complex 39B at Kennedy Space Center (KSC) in Florida, where the stack was fueled and countdown procedures practiced. These rehearsals uncovered various technical issues, including hydrogen leaks and faulty sensors, leading to delays.
Furthermore, tropical weather systems, including Hurricanes Ian and Nicole, forced multiple rollbacks of the integrated stack from the launch pad to the Vehicle Assembly Building (VAB) for protection, adding to the mission's complexity and extending the timeline. Each rollback and rollout, involving the Crawler-Transporter, was a meticulous, multi-day operation.
The launch windows for Artemis I were precisely calculated to ensure the correct planetary alignment for Orion's trajectory to the Moon and its return, with specific considerations for lighting conditions during launch and splashdown. Thousands of personnel across NASA centers and contractor facilities worked tirelessly, from the ground systems engineers at KSC to the launch control team in Firing Room 1, to prepare for the historic liftoff.
Liftoff: Power and Precision
After several scrubs, Artemis I successfully launched on November 16, 2022, at 1: 47 AM EST, from Launch Complex 39B at Kennedy Space Center. The liftoff was a spectacular display of raw power, as the SLS rocket, generating 8.8 million pounds of thrust, ascended into the pre-dawn sky.
The initial ascent phase saw the two solid rocket boosters (SRBs) ignite simultaneously with the four RS-25 engines of the Core Stage. Approximately two minutes into the flight, the SRBs jettisoned, having expended their fuel. The Core Stage continued to burn for another six minutes, propelling Orion to an altitude of over 100 miles before its main engines cut off (MECO) and the stage separated.
Following Core Stage separation, the Interim Cryogenic Propulsion Stage (ICPS) ignited its single RL10 engine for a "perigee raise" burn, establishing a stable orbit around Earth. After one and a half orbits, the ICPS performed the crucial Trans-Lunar Injection (TLI) burn, firing for approximately 18 minutes to accelerate Orion to over 22,600 miles per hour, sending it on a precise trajectory towards the Moon. Shortly after TLI, Orion deployed its solar arrays, extending them to span 62 feet and begin generating power for the spacecraft.
Outbound Journey: Testing Orion’s Systems
During its multi-day journey to the Moon, Orion underwent extensive system checks and calibrations. Mission controllers at NASA's Johnson Space Center in Houston meticulously monitored the spacecraft's propulsion, navigation, communication, and thermal control systems. The Deep Space Network (DSN), a global network of large radio antennas, played a vital role in maintaining continuous communication and tracking Orion's precise location and velocity.
A significant aspect of the outbound journey was the deployment of ten CubeSats, small satellites designed for various scientific and technological demonstrations. These included BioSentinel, which carried yeast cells to study the effects of deep space radiation on living organisms; OMOTENASHI, a Japanese lunar lander demonstrator; and EQUULEUS, another Japanese CubeSat designed to image Earth's plasmasphere and demonstrate low-thrust trajectory control. These secondary payloads provided additional scientific data and testbeds for future small satellite missions.
The Lunar Fly-by Maneuver: Closest Approach
The critical lunar fly-by maneuver occurred on November 21, 2022, just five days after launch. Orion made its closest approach to the lunar surface at 7:57 AM EST, passing approximately 81 miles (130 kilometers) above the Moon's far side. This close pass was not merely a visual spectacle but a precisely engineered maneuver.
During the fly-by, Orion performed an outbound powered fly-by burn, firing its main engine for approximately two and a half minutes. This burn was crucial for adjusting the spacecraft's trajectory, using the Moon's gravity to slingshot Orion towards its distant retrograde orbit (DRO). The maneuver was executed flawlessly, demonstrating the precision navigation and propulsion capabilities of the