Lunar Gateway

Lunar orbital space station under development

Gateway
An illustration of the Gateway's Power and Propulsion Element (PPE) and Habitation and Logistics Outpost (HALO) in orbit around the Moon in 2025
Station statistics
CrewMax 4 (planned)
LaunchNovember 2025 (planned)[1]
Carrier rocketFalcon Heavy
SLS Block 1B
Launch padKennedy Space Center Launch Complex 39
Mission statusIn development
Pressurised volume≥125 m3 (4,400 cu ft) (planned)[2]
Periselene altitude3,000 km (1,900 mi)[3]
Aposelene altitude70,000 km (43,000 mi)
Orbital inclinationPolar near-rectilinear halo orbit (NRHO)
Orbital period≈7 days
Configuration
Configuration as of 16 November 2022
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The Lunar Gateway, or simply Gateway, is a space station which Artemis program participants plan to assemble in an orbit near the Moon. The Gateway is intended to serve as a communication hub, science laboratory, and habitation module for astronauts. It is a multinational collaborative project: participants include NASA, the European Space Agency (ESA), the Japan Aerospace Exploration Agency (JAXA), the Canadian Space Agency (CSA) and the Mohammed Bin Rashid Space Centre (MBRSC). The Gateway is planned to be the first space station beyond low Earth orbit.[4][5]

The science disciplines to be studied on the Gateway are expected to include planetary science, astrophysics, Earth observation, heliophysics, fundamental space biology, and human health and performance.[6] As of April 2024 construction is underway of the initial habitation and propulsion modules.[7][8][9] The International Space Exploration Coordination Group (ISECG), which is composed of 14 space agencies including NASA, has concluded that Gateway systems will be critical in expanding human presence to the Moon, to Mars, and deeper into the Solar System.[10]

The project is expected to play a major role in the Artemis program after 2024. While the project is led by NASA, the Gateway is meant to be developed, serviced, and utilized in collaboration with the CSA, ESA, JAXA, and commercial partners. It will serve as the staging point for both robotic and crewed exploration of the lunar south pole and is the proposed staging point for NASA's Deep Space Transport concept for transport to Mars.[11][7][12]

History

Background

The Apollo Command and Service Module was the first crewed lunar orbiting spacecraft performing dockings and crew transfers with another spacecraft, the Apollo lander. Lunar bases, like the first Tranquility Base as well as concepts for lunar bases have been the main focus of human presence at the Moon.

Prior names

Formerly known as the Deep Space Gateway (DSG), the station was renamed Lunar Orbital Platform-Gateway (LOP-G) in NASA's 2018 proposal for the 2019 United States federal budget.[13][14] When the NASA budget was signed into law on February 15, 2019,[15] US$450 million had been committed by Congress to preliminary studies.[15][16]

Studies

2012 concept for the Deep Space Habitat, consisting of a cryogenic propulsion stage, an ISS-derived habitat module, and a MPLM

An earlier NASA proposal for a cislunar station had been made public in 2012 and was dubbed the Deep Space Habitat. That proposal led to funding in 2015 under the NextSTEP program to study the requirements of deep space habitats.[17] In February 2018, it was announced that the NextSTEP studies and other ISS partner studies would help to guide the capabilities required of the Gateway's habitation modules.[18] The solar electric Power and Propulsion Element (PPE) of the Gateway was originally a part of the now-canceled Asteroid Redirect Mission.[19][20] On 7 November 2017, NASA asked the global science community to submit concepts for scientific studies that could take advantage of the Deep Space Gateway's location in cislunar space.[6] The Deep Space Gateway Concept Science Workshop was held in Denver, Colorado, from 27 February to 1 March 2018. This three-day conference was a workshop where 196 presentations were given for possible scientific studies that could be advanced through the use of the Gateway.[21]

In 2018, NASA initiated the Revolutionary Aerospace Systems Concepts Academic Linkage (RASC-AL) competition for universities to develop concepts and capabilities for the Gateway. The competitors were asked to employ original engineering and analysis in one of four areas; "Gateway Uncrewed Utilization and Operations", "Gateway-Based Human Lunar Surface Access", "Gateway Logistics as a Science Platform", and "Design of a Gateway-Based Cislunar Tug". Teams of undergraduate and graduate students were asked to submit a response by 17 January 2019 addressing one of these four themes. NASA selected 20 teams to continue developing proposed concepts. Fourteen of the teams presented their projects in person in June 2019 at the RASC-AL Forum in Cocoa Beach, Florida, receiving a US$6,000 stipend to participate in the Forum.[5] The "Lunar Exploration and Access to Polar Regions" from the University of Puerto Rico at Mayagüez was the winning concept.[22]

NASA unveiled the name of the lunar-orbit space station in November 2019, and the Gateway with its name and logo associated with the American frontier symbol of the St. Louis Gateway Arch.[23]

International participants

On 27 September 2017, an informal joint statement on cooperation regarding the program between NASA and Russia's Roscosmos was announced.[9] However, in October 2020 Dmitry Rogozin, director general of Roscosmos, said that the program is too “U.S.-centric” for Roscosmos to participate in,[24] and in January 2021, Roscosmos announced that it would not participate in the program.[25]

As of January 2024, the Canadian Space Agency (CSA), the European Space Agency (ESA), Japan Aerospace Exploration Agency (JAXA) and Mohammed Bin Rashid Space Centre (MBRSC) all plan to participate in the Gateway project, each contributing a robotic arm called Canadarm3 (CSA), refuelling and communications hardware, habitation and research capacity and an airlock module. These international elements are intended to launch after the initial NASA PPE and HALO elements are placed into lunar orbit with some co-manifested with Artemis missions .[26]

Power and propulsion

Gateway - Power and Propulsion Element

On 1 November 2017, NASA commissioned five studies lasting four months into affordable ways to develop the Power and Propulsion Element (PPE), leveraging private companies' plans. These studies had a combined budget of US$2.4 million. The companies performing the PPE studies were Boeing, Lockheed Martin, Orbital ATK, Sierra Nevada and Space Systems/Loral.[27][20] These awards are in addition to the ongoing set of NextSTEP-2 awards made in 2016 to study development and make ground prototypes of habitat modules that could be used on the Gateway as well as other commercial applications,[12] so the Gateway is likely to incorporate components developed under NextSTEP as well.[20][28] The PPE will use four 6 kW BHT-6000 Busek Hall-effect thrusters[29][30][31] and three 12 kW NASA/Aerojet Rocketdyne Advanced Electric Propulsion System (AEPS) Hall-effect thrusters for a total engine output fractionally under 50 kW.[32] In 2019, the contract to manufacture the PPE was awarded to Maxar Technologies.[33] After a one-year demonstration period, NASA would then "exercise a contract option to take over control of the spacecraft".[34] Its expected service time is about 15 years.[35] In late 2023, it was reported that flight qualification testing was occurring on the thrusters for the Power and Propulsion Element.[36]

Orbit and operations

The Gateway will be deployed in a near-rectilinear halo orbit (NRHO) around the Moon.[37] The eccentricity of the chosen NRHO takes the station within 1,500 km (930 mi) of the lunar north pole surface at closest approach, and as far away as 70,000 km (43,000 mi) over the lunar south pole, with a period of about 7 days.[3][38][39] One of the advantages of an NRHO is the minimal amount of communications blackout with the Earth.

Traveling to and from cislunar space (lunar orbit) is intended to develop the knowledge and experience necessary to venture beyond the Moon and into deep space. The proposed NRHO would allow lunar expeditions from the Gateway to reach a low polar orbit with a Δv of 730 m/s and a half a day of transit time. Orbital station-keeping would require less than 10 m/s of Δv per year, and the orbital inclination could be shifted with a relatively small Δv expenditure, allowing access to most of the lunar surface. Spacecraft launched from Earth would perform a powered flyby of the Moon v ≈ 180 m/s) followed by a Δv ≈ 240 m/s NRHO insertion burn to dock with the Gateway as it approaches the apoapsis point of its orbit. The total travel time would be 5 days; the return to Earth would be similar in terms of trip duration and Δv requirement if the spacecraft spends 11 days at the Gateway. The crewed mission duration of 21 days and Δv ≈ 840 m/s is limited by the capabilities of the Orion life support and propulsion systems.[40]

Gateway will be the first modular space station to be both human-rated, and autonomously operating most of the time in its early years, as well as being the first deep-space station, far from low Earth orbit. This will be enabled by more sophisticated executive control software than on any prior space station, which will monitor and control all systems. The high-level architecture is provided by the Robotics and Intelligence for Human Spaceflight lab at NASA and implemented at NASA facilities. The Gateway could conceivably also support in-situ resource utilization (ISRU) development and testing from lunar and asteroid sources,[41] and would offer the opportunity for a gradual buildup of capabilities for more complex missions over time.[42]

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