Lunar oxygen pipeline vulnerability model

By Dr. Chris Flaherty

In this edition, we are going to look at a recent proposal for an end-to-end system-level design study appearing on the NASA website for a L-SPoP: Lunar South Pole Oxygen Pipeline (Curreri, 2023). Proposals such as these for building Lunar Surface Infrastructure (LSI) raise some potentially interesting questions, as to how we would look at infrastructure vulnerability issues, normally applied here on Earth, for a build on the Lunar Surface? And rather than just science fiction, these projects are being pitched for implementation next year between 2024 and 2026!

L-SPoP Proposal

The L-SPoP proposal is based on the requirement that Artemis Program sustainability – the goal of which is developing a permanent Human presence on the Moon - is dependent on ability to utilize in-situ resources to reduce the cost and risk of Lunar operations. This project looks at solving the problem of how to efficiently and cheaply truck oxygen extracted from Lunar regolith, and water from Lunar ice, with the use of a pipeline. A Human Habitat or Liquification Plant that needs a regular supply of oxygen and water may be situated (to meet mission requirements) a long distance away from an

Extraction Area. It may be the case, that a radial network is developed servicing a distributed settlement covering a wider geographical area on the Lunar surface. As a possible mitigation strategy to enhance security from threats posed by random strikes, this may necessitate a distributed model of settlement. It can also be anticipated that as International Lunar Missions increase there will evolve a Lunar Commercial Services Entity connecting newcomers to the system – just think about how we setup new homes and industrial areas in cities, and apply this to the Moon!

The L-SPoP proposal has as its goal extracted oxygen will be used to provide: (1) Human Habitats, rovers, other Life Support Systems with a constant supply of high purity oxygen for Human consumption; (2) Oxidizer for launch vehicles departing the Moon (Curreri, 2023). It is generally known that the NASA program timetable for Oxygen Extraction Technologies are planned for large-scale demonstration on the Moon by early 2024, and providing direct support to Artemis Astronauts by 2026.

The L-SPoP proposal’s starting concept is for a 3.1 miles: 5 kilometres pipeline to transport oxygen gas from an Oxygen Production Source, to an Oxygen Storage/ Liquification Plant near a Lunar Base – Human Habitat. It is proposed that pipeline components are made from local Lunar surface aluminium deposits (other local metals could also be considered). Pipeline components would be passivated (made unreactive by altering the surface layer or coating the surface with a thin inert layer), and welded or fitted together. The proposal also suggests the pipeline could be constructed and repaired robotically. It is intended the pipeline would have a high operational reliability, and be able to survive in the Lunar environment for greater than 10 years.

Lunar Vulnerability Threat Analysis Model

If we are able to build between 2024 and 2026 a 3.1 miles: 5 kilometres pipeline to transport oxygen gas from an Oxygen Production Source, to where it is needed a key risk would be damage to the pipe, or infrastructure elements from a random meteorite. Earth has a protective atmosphere where meteoroids usually disintegrate. The Moon with little or no atmosphere makes its surface vulnerable to frequent impacts.

Current NASA studies of the Lunar impact rate estimate 11 to 1,100 tons: equivalent to the mass of about 5.5 cars, of dust collide with the Moon every day. A further 100 pingpong-ball-sized rocks hit the Moon over the same day. This statistic equates with approximately 33,000 strikes per year. Statistically, the odds are quite low, as the Moon’s surface area is about 14.6 million square miles: 38 million square kilometres, and any patch of ground will be hit potentially by a pingpong-sized object once every thousand years or so.

The slowest impacting rock travels at 45,000 milesper-hour: 20 kilometres-per-second; the fastest travels at over 160,000 miles-per-hour: 72 kilometresper-second.

In 2019, a meteorite was recorded impacting the Moon’s surface at 38,000 miles-per-hour: 61,000 kilometres-perhour carving out a crater about 10 to 15 meters: 33 to 50 feet in diameter. The slowest impacting rock travels at 45,000 miles-per-hour: 20 kilometres-per-second; the fastest travels at over 160,000 miles-per-hour: 72 kilometres-persecond. At such speeds even a small object with a mass of only 10 pounds: 5 kilograms has enough energy to excavate a crater over 30 feet: 9 meters across, while hurling 75 tons of Lunar soil and rock on ballistic trajectories above the surface. In terms of scale of impact a pingpong-ball-size rock strikes the surface with the explosive force of 7 pounds: 3.2 kilograms. A larger rock, around 8 feet: 2.5 meters across, strike every four years, with an explosive force of a kiloton.

The only potential threat to any Lunar Surface Infrastructure (LSI) are randomized periodic meteorite strikes spread over the entire surface area of the Moon. While, odds for such an event are low, the impact – consequences of an event occurring at or near infrastructure could be potentially catastrophic. The Vulnerability Analysis model, is similar to how we might view a terrorism bombing on Earth. The Lunar surface is visualized as an Attack Surface where an Oxygen Pipeline traverses the area. Managing the route, this is divided into segments, each monitored by a Pipeline Segment Sensor. As well, Lunar Reconnaissance Orbiter photographs of the pipe and its surrounding area can be regularly examined to see it any craters have appeared, and this data can be assessed for potential risks or damage done to the pipe. Conceptualized as a series of 3D Vulnerability Analysis Boxes - this is where a piece of infrastructure is divided into parts, and where all the vulnerability data for that specific area is identified. If there is the risk of damage from a nearby random strike then the relevant vulnerability data can be looked at, to see if there are potential issues that need further investigation, even if the Segment Sensors are not showing an issue.

It should be noted a key factor affecting vulnerability, is how has a piece of Lunar Surface Infrastructure (LSI) been designed to withstand impacts. For instance, the L-SPoP proposal’s modular design goal is to develop an adaptable, repairable, and evolvable structure (Curreri, 2023).

For all you Earthbound civil construction engineers, and project managers it is time to swap your business suits for a Lunar Surface Spacesuit. And Yes – you can still put a tie on a Spacesuit!