Lunar oxygen pipeline would require 175x less energy than moon rovers

To build its permanent colony on the moon, NASA will need innovative new ideas from private partners to help it build the habitats and the infrastructure required to keep future lunar astronauts safe. As part of its plans for building its colony, NASA has proposed transporting oxygen — derived from ice in the lunar south pole — via rovers.

Recently though, Peter Curreri, Chief Science Officer at Lunar Resources Inc., wrote up a counter-proposal in which he suggested a lunar pipeline would be the more efficient and safer option.

Curreri filed his proposal to the space agency's Innovative Advanced Concepts (NIAC) program, and he was one of 14 research teams awarded $175,000 in funding to develop their concepts.

In an interview with Interesting Engineering (IE), Curreri explained the thinking behind the lunar pipeline idea, as well as the role NASA’s funding will play in developing the concept further.

The following conversation has been lightly edited for clarity and flow.

Interesting Engineering: Why is a lunar pipeline a better solution than lunar rovers for transporting oxygen on the moon?

Peter Curreri: Rovers with attached robotics and regolith-moving gear are essential to plans for a sustainable human presence on the moon. Although Lunar Resources is not developing rovers, we are working with partners who will use them to mechanize lunar operations. For the transport of small amounts of oxygen for short distances (tens of meters), rovers transporting cryogenic or pressurized tanks can be a good solution.

However, for larger amounts of oxygen transported over larger distances, pipelines become more efficient. The Artemis base is projected to need 10 MT of oxygen per year for initial operations. With commercial development, the required quantity will become much greater. Considering the potential scale of Lunar South Pole operations, the transport distances from oxygen production to the habitats and launch pads where it will be required is considerable, perhaps requiring supply lines of 10s to 100s of kilometers. 

We are baselining a 5 km oxygen pipeline that can transport 10 MT of oxygen per year in the lunar South Pole region. For this distance and capacity, our calculations show that the amount of energy needed to transport the oxygen is 175x less than for the rover model. A simple way to understand why pipelines are more efficient is that If you want to transport that oxygen by rover, you need to put a small fraction of that into a tank. Then you need to transport the weight of the rover, tank, and oxygen 5 km to the consumer. Next, you must transport the weight of the rover and the empty tank 5 km back to the source. You repeat this over and over. With a pipeline, you just transport the weight of the oxygen. 

IE: Did Lunar Resources consider any technologies other than a pipeline for transporting oxygen on the moon?

In our NIAC Phase I, we plan to compare pipelines with transport by rovers and rail.

IE: What are the possible risks? Could a pipeline leak put an entire oxygen supply at risk? What methods would be used to mitigate these types of problems?

We are working with our partner, Wood PLC, to design the Lunar South Pole Oxygen Pipeline, LSPOP.  Wood has extensive experience engineering pipelines on Earth. The lunar pipeline would contain the normal safeguards, which include pressure gages to detect leaks, valving to isolate leaks, and a method to repair and replace damaged sections. 

IE: Now that you have secured the NIAC funds, what's the next step in terms of developing the pipeline concept?

The NIAC Phase I, which is a 9-month program, focuses on proving the feasibility of an in-situ built lunar pipeline.  For NIAC Phase II, we will do proof of concept sub-scale testing and more detailed engineering. Following that would be the development of flight-forward designs and components that would lead to a lunar demonstration.  With a successful demonstration, lunar construction and operations of the South Pole Lunar Oxygen Pipeline could begin.

IE: Could you also tell us a bit about Lunar Resource's MW Program? Will this tie in with the pipeline project in any way?

The lunar oxygen pipeline will integrate with a suite of lunar infrastructure that Lunar Resources Inc. (LUNAR) is developing. LSPOP will be powered by electric energy made by LUNAR’s in-situ constructed solar arrays. It will utilize materials extracted from lunar regolith utilizing LUNAR’s molten regolith electrolysis system.  It will be constructed using LUNAR’s energy-efficient 3D printers.