Want to go to Mars? We should mine the moon for rocket fuel first

An artist's impression of a moon colony, dating from 1986. Image: NASA/Dennis M. Davidson

Forty-five years have passed since humans last set foot on an extraterrestrial body. Now, the moon is back at the center of efforts not only to explore space, but to create a permanent, independent space-faring society. The Conversation

Planning expeditions to Earth’s nearest celestial neighbor is no longer just a NASA effort, though the US space agency has plans for a moon-orbiting space station that would serve as a staging ground for Mars missions in the early 2030s. The United Launch Alliance, a joint venture between Lockheed Martin and Boeing, is planning a lunar fueling station for spacecraft, capable of supporting 1,000 people living in space within 30 years.

Billionaires Elon Musk, Jeff Bezos and Robert Bigelow all have companies aiming to deliver people or goods to the moon. Several teams competing for a share of Google’s $30m cash prize are planning to launch rovers to the moon.

We and 27 other students from around the world recently participated in the 2017 Caltech Space Challenge, proposing designs of what a lunar launch and supply station for deep space missions might look like, and how it would work.

The raw materials for rocket fuel

Right now all space missions are based on, and launched from, Earth. But Earth’s gravitational pull is strong. To get into orbit, a rocket has to be traveling 11 kilometers a second – 25,000 miles per hour.

Any rocket leaving Earth has to carry all the fuel it will ever use to get to its destination and, if needed, back again. That fuel is heavy – and getting it moving at such high speeds takes a lot of energy. If we could refuel in orbit, that launch energy could lift more people or cargo or scientific equipment into orbit. Then the spacecraft could refuel in space, where Earth’s gravity is less powerful.

The moon has one-sixth the gravity of Earth, which makes it an attractive alternative base. The moon also has ice, which we already know how to process into a hydrogen-oxygen propellant that we use in many modern rockets.

Roving Luna

NASA’s Lunar Reconnaissance Orbiter and Lunar Crater Observation and Sensing Satellite missions have already found substantial amounts of ice in permanently shadowed craters on the moon.

Those locations would be tricky to mine because they are colder and offer no sunlight to power roving vehicles. However, we could install big mirrors on the craters’ rims to illuminate solar panels in the permanently shadowed regions.

Mining operations on the moon, an artist’s rendering. Image: Sung Wha Kang (RISD)/creative commons.

Rovers from Google’s Lunar X Prize competition and NASA’s Lunar Resource Prospector, set to launch in 2020, would also contribute to finding good locations to mine ice.

Imagining a moon base

Depending on where the best ice reserves are, we might need to build several small robotic moon bases. Each one would mine ice, manufacture liquid propellant and transfer it to passing spacecraft. Our team developed plans to accomplish those tasks with three different types of rovers. Our plans also require a few small robotic shuttles to meet up with nearby deep-space mission vehicles in lunar orbit.

An artist’s rendering of lunar rover concepts. Image: Sung Wha Kang (RISD)/creative commons.

One rover, which we call the Prospector, would explore the moon and find ice-bearing locations. A second rover, the Constructor, would follow along behind, building a launch pad and packing down roadways to ease movements for the third rover type, the Miners, which actually collect the ice and deliver it to nearby storage tanks and an electrolysis processing plant that splits water into hydrogen and oxygen.

The Constructor would also build a landing pad where the small near-moon transport spacecraft we call Lunar Resupply Shuttles would arrive to collect fuel for delivery as newly launched spacecraft pass by the moon. The shuttles would burn moon-made fuel and would have advanced guidance and navigation systems to travel between lunar bases and their target spacecraft.

A gas station in space

An artist’s rendering of a fuel depot for refueling deep-space missions. Image: Sung Wha Kang (RISD)/creative commons.

When enough fuel is being produced, and the shuttle delivery system is tested and reliable, our plan calls for building a gas station in space. The shuttles would deliver ice directly to the orbiting fuel depot, where it would be processed into fuel and where rockets heading to Mars or elsewhere could dock to top up.

The depot would have large solar arrays powering an electrolysis module for melting the ice and then turning the water into fuel, and large fuel tanks to store what’s made. NASA is already working on most of the technology needed for a depot like this, including docking and fuel transfer. We anticipate a working depot could be ready in the early 2030s, just in time for the first human missions to Mars.

To be most useful and efficient, the depot should be located in a stable orbit relatively near both the Earth and the moon. The Earth-moon Lagrangian Point 1 (L1) is a point in space about 85 percent of the way from Earth to the moon, where the force of Earth’s gravity would exactly equal the force of the moon’s gravity pulling in the other direction. It’s the perfect pit stop for a spacecraft on its way to Mars or the outer planets.

Leaving Earth

Our team also found a fuel-efficient way to get spacecraft from Earth orbit to the depot at L1, requiring even less launch fuel and freeing up more lift energy for cargo items. First, the spacecraft would launch from Earth into Low Earth Orbit with an empty propellant tank.

An artist’s rendering of a solar electric propulsion tug above an asteroid. Image: NASA.

Then, the spacecraft and its cargo could be towed from Low Earth Orbit to the depot at L1 using a solar electric propulsion tug, a spacecraft largely propelled by solar-powered electric thrusters.

This would let us triple the payload delivery to Mars. At present, a human Mars mission is estimated to cost as much as $100bn, and will need hundreds of tons of cargo. Delivering more cargo from Earth to Mars with fewer rocket launches would save billions of dollars and years of time.

A base for space exploration

Building a gas station between Earth and the moon would also reduce costs for missions beyond Mars. NASA is looking for extraterrestrial life on the moons of Saturn and Jupiter. Future spacecraft could carry much more cargo if they could refuel in space – who knows what scientific discoveries sending large exploration vehicles to these moons could enable?

By helping us escape both Earth’s gravity and dependence on its resources, a lunar gas station could be the first small step toward the giant leap into making humanity an interplanetary civilization.


The authors of this article were: Gary Li, Ph.D. Candidate in Mechanical and Aerospace Engineering, University of California, Los Angeles; Danielle DeLatte, Ph.D. Student in Aeronautics & Astronautics, University of Tokyo; Jerome Gilleron, Ph.D. Candidate in Aerospace Engineering, Georgia Institute of Technology; Samuel Wald, Ph.D. Student in Aeronautics and Astronautics, Massachusetts Institute of Technology; and Therese Jones, Ph.D. Candidate in Public Policy, Pardee RAND Graduate School.

This article was originally published on The Conversation. Read the original article.

 
 
 
 

Five lessons for cities from a decade of Centre for Cities research

The view of Vancouver from Locarno Beach Park. Image: Getty.

With the government potentially facing years of “trench warfare” in Parliament, and Brexit set to dominate the national political agenda for the foreseeable future, local leaders have the chance to play a critical role in driving the UK’s economy in the coming years. However, it’s also clear that UK cities will face big challenges in the new economic circumstances outside the EU, and in responding to other issues such as globalisation and automation.

To meet these challenges and opportunities, local leaders will need to make the most of their existing resources and powers – and one of the best ways to do so is to learn from the experiences and ideas of other places.

That’s why the Centre for Cities recently launched a new, easy-to-navigate case study library featuring over 150 examples of good practice from cities in the UK and across the world. Drawn from more than 10 years of Centre for Cities research, the library offers examples of innovative and effective urban policy making in areas such as housing and transport, skills and employment, business and enterprise, and leadership.

In the process of compiling the case study library, five key lessons for cities stood out in particular:

1) Pooling resources with other local authorities can help places achieve more than they can do on their own.

Take Cambridge, for example. Its ability to deliver housing changed in the mid-2000s thanks to the establishment of the Cambridge sub-regional housing board.

By working in partnership with neighbouring authorities (as well as with development companies and a strategic planning unit), Cambridge has been able to reach a consensus on the importance of increasing density and introducing transport-oriented urban extensions.

2) Cities should also make the most of the support and initiatives that non-public sector partners can offer.

For example, Manchester City Council worked in partnership with NESTA and other agencies to launch an innovative ‘Creative Credit’ voucher scheme in 2010. Through this initiative, small and medium sized enterprises (SMEs) in the city region were given vouchers worth £4,000 to spend on buying services from creative companies provided they spent at least £1,000 themselves. The pilot was oversubscribed and its evaluation showed a positive impact on sales and the innovation capacity of participants.

3) Having a clear understanding of the needs of people targeted by a specific programme or project will be vital in its success.

This is demonstrated by the success of Blade Runners, an employment programme set up by the City of Vancouver to support 15-30 year olds facing multiple barriers from getting into training and/or employment (such as substance misuse, homelessness, transportation costs and legal issues).

Three quarters of the participants in the programme completed training and moved into jobs, a success rate made possible by the continuous, targeted support provided by Blade Runners coordinators. This included referring participants to appropriate resources, and providing them with breakfast and lunch, living allowances, travel tickets, tools, equipment and work gear for training.


4) Even when cities do not have formal powers to make a difference, they can still use their leadership role to influence and inspire positive changes.

For example, in 2010 the then Mayor of London Boris Johnson launched the London Apprenticeship Campaign which aimed to increase awareness of the scheme. Letters signed by the London Mayor were sent to CEOs of large businesses outlining the value of apprenticeships, and the potential benefits of recruiting apprentices. The campaign had a positive impact on raising awareness among employers and helped to boost the profile of apprenticeships in London.

5) Monitoring and evaluating projects from their early stages is crucial for their long-term success.

San Francisco offers a clear example of how long term policy making coupled with close monitoring can drive change and create jobs. In 2002, the city set itself the goal of a 75 per cent reduction in landfill waste by 2010 and zero waste by 2020. Thanks to close evaluation of the projects, the city realised its efforts were not enough to reach the target, and so introduced a further 20 laws to address these issues. The city is now ahead of its schedule in meeting objectives.

You can access the case study library and to read about these examples in more detail here. We are always keen to hear about new case studies, so please do get in contact if you’d like to share good practice from your city.

Elena Magrini is a researcher at the Centre for Cities, on whose website this article originally appeared.

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