Dev Diary #12 - The Lunar Orbit Station - Part I
[p]Welcome to the twelfth Dev Diary entry of 'Space Station Designer'. The last two entries covered the two stations available in higher Earth orbits: the GSO station and the L2 station. In this new entry, we're going to start another two-part series with the goal of analyzing the details behind the Lunar Orbit station, including what makes it unique, and how it contributes to the development of the Lunar Space Elevator Megaproject.
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The Earth-Moon Lagrange Point 1 (L1)[/h3][p]The Lunar Orbit station is located in the Earth-Moon Lagrange Point 1, also known as L1. This point is a location in space situated between the Earth and the Moon where the gravitational forces of both celestial bodies balance out. The L1 point lies approximately 85% of the distance from Earth to the Moon, making it roughly 326,400 km from the Earth's center (the average distance between the Earth and the Moon is 384,400 km).
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At L1, the combined gravitational pull of the Earth and Moon balances the centrifugal force, allowing a spacecraft, or a space station, to "hover" with reduced fuel requirements. L1's location provides several benefits, and makes it a very convenient location for a Lunar Orbit station. Some of these benefits include:[/p]![]()
Orbit Control and Distance to the L1 point[/h3][p]As mentioned earlier, L1 point is a very unstable point. Because of this, we need to ensure that there's adequate propulsion modules installed in order to maintain a healthy 'orbit control' score. In the LEO station, having an adequate 'orbit control' score ensures that the station maintains an orbit of 460 km around the Earth. In the case of the Lunar Orbit station, having an adequate 'orbit control' score has a slightly different implication. More specifically, the Lunar Orbit station needs to be kept as close to the L1 point as possible.[/p][p]Failure to provide a proper 'orbit control' score will cause the station to start drifting away from L1. If the distance to L1 exceeds a certain threshold (currently set to 20 km), it will have an impact on the Lunar Space Elevator Megaproject. More details about this in an upcoming blog post.
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Attitude Control[/h3][p]Similar to what happens with the Earth stations (i.e., LEO, GSO, and L2), the Lunar Orbit station can occasionally go through an orbital debris shower, albeit at a much lower rate compared to the LEO station as there are fewer satellites in Lunar Orbit. Because of this, it's still important to ensure that we keep a healthy 'attitude control' score to increase our chances of successfully executing a Debris Avoidance Maneuver (DAM).[/p][h3]Resupply spacecraft[/h3][p]The Lunar Orbit station is located far away from the Earth. Similarly to what happens with the L2 station, it takes a considerable amount of time and propulsion reserves to get there, along with a larger heatshield to withstand the fiery re-entry. For this reason, only a subset of the available resupply spacecraft can make their way to this station.
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Coming Up Next[/h3][p]This blog post covered some preliminary details of the Lunar Orbit station, which is located in the Earth-Moon Lagrange Point 1 or 'L1', along with the features and capabilities that make it unique. In the next Dev Diary, we'll discuss manufacturing, space tourism, research/Industrial R&D, and how the Lunar Orbit station is the basis for the construction of the Lunar Space Elevator.[/p][p]We're currently running a closed beta for 'Space Station Designer' (more information here). In early September we'll be releasing the next update (version 0.5.70), which will include several gameplay changes and a fully revised set of interactive tutorials. If you're interested in trying out 'Space Station Designer', please consider applying to the closed beta and help us shape its future.[/p][p]See you in the next Dev Diary!
[/p][p]--Ignacio, Mauricio, and Nicolas (Polar Motion)
Wishlist Space Station Designer
[dynamiclink][/dynamiclink][/p]
[/p][h3]
The Earth-Moon Lagrange Point 1 (L1)[/h3][p]The Lunar Orbit station is located in the Earth-Moon Lagrange Point 1, also known as L1. This point is a location in space situated between the Earth and the Moon where the gravitational forces of both celestial bodies balance out. The L1 point lies approximately 85% of the distance from Earth to the Moon, making it roughly 326,400 km from the Earth's center (the average distance between the Earth and the Moon is 384,400 km).
[/p][p]
At L1, the combined gravitational pull of the Earth and Moon balances the centrifugal force, allowing a spacecraft, or a space station, to "hover" with reduced fuel requirements. L1's location provides several benefits, and makes it a very convenient location for a Lunar Orbit station. Some of these benefits include:[/p]
- [p]A constant communication link between the Earth and lunar operations.[/p]
- [p]An ideal location for monitoring solar wind and its effects on Earth's magnetosphere.[/p]
- [p]A convenient location that is relatively easy to reach from both the Earth and the Moon.[/p]
- [p]A fixed point above the lunar surface, which makes it ideal for setting up a Space Elevator ;)[/p]
- [p]L1 Instability: The L1 point is inherently unstable, which requires constant thrust or regular small maneuvers to maintain the station at the required position.[/p]
- [p]Orbital Maintenance: The Moon's elliptical orbit and solar radiation pressure can significantly perturb the station, which makes the station-keeping process more involved.[/p]
- [p]Radiation: High-energy particles from solar wind and cosmic rays are definitely a concern. These particles increase the need for robust radiation shielding for crew and sensitive equipment, which is reflected in the cost (and mass) of the modules.[/p]
Orbit Control and Distance to the L1 point[/h3][p]As mentioned earlier, L1 point is a very unstable point. Because of this, we need to ensure that there's adequate propulsion modules installed in order to maintain a healthy 'orbit control' score. In the LEO station, having an adequate 'orbit control' score ensures that the station maintains an orbit of 460 km around the Earth. In the case of the Lunar Orbit station, having an adequate 'orbit control' score has a slightly different implication. More specifically, the Lunar Orbit station needs to be kept as close to the L1 point as possible.[/p][p]Failure to provide a proper 'orbit control' score will cause the station to start drifting away from L1. If the distance to L1 exceeds a certain threshold (currently set to 20 km), it will have an impact on the Lunar Space Elevator Megaproject. More details about this in an upcoming blog post.
[/p][h3]
Attitude Control[/h3][p]Similar to what happens with the Earth stations (i.e., LEO, GSO, and L2), the Lunar Orbit station can occasionally go through an orbital debris shower, albeit at a much lower rate compared to the LEO station as there are fewer satellites in Lunar Orbit. Because of this, it's still important to ensure that we keep a healthy 'attitude control' score to increase our chances of successfully executing a Debris Avoidance Maneuver (DAM).[/p][h3]Resupply spacecraft[/h3][p]The Lunar Orbit station is located far away from the Earth. Similarly to what happens with the L2 station, it takes a considerable amount of time and propulsion reserves to get there, along with a larger heatshield to withstand the fiery re-entry. For this reason, only a subset of the available resupply spacecraft can make their way to this station.
[/p][h3]
Coming Up Next[/h3][p]This blog post covered some preliminary details of the Lunar Orbit station, which is located in the Earth-Moon Lagrange Point 1 or 'L1', along with the features and capabilities that make it unique. In the next Dev Diary, we'll discuss manufacturing, space tourism, research/Industrial R&D, and how the Lunar Orbit station is the basis for the construction of the Lunar Space Elevator.[/p][p]We're currently running a closed beta for 'Space Station Designer' (more information here). In early September we'll be releasing the next update (version 0.5.70), which will include several gameplay changes and a fully revised set of interactive tutorials. If you're interested in trying out 'Space Station Designer', please consider applying to the closed beta and help us shape its future.[/p][p]See you in the next Dev Diary!
[/p][p]--Ignacio, Mauricio, and Nicolas (Polar Motion)
Wishlist Space Station Designer
[dynamiclink][/dynamiclink][/p]