Building a Lunar Base with 3D Printing

31 January 2013. Copyright European Space Agency (ESA). Reproduced with permission.

Lunar base made with 3D printing
Lunar base made with 3D printing

Setting up a lunar base could be made much simpler by using a 3D printer to build it from local materials. Industrial partners including renowned architects Foster + Partners have joined with ESA to test the feasibility of 3D printing using lunar soil.

“Terrestrial 3D printing technology has produced entire structures,” said Laurent Pambaguian, heading the project for ESA.

“Our industrial team investigated if it could similarly be employed to build a lunar habitat.”

Foster + Partners devised a weight-bearing ‘catenary’ dome design with a cellular structured wall to shield against micrometeoroids and space radiation, incorporating a pressurised inflatable to shelter astronauts.

A hollow closed-cell structure – reminiscent of bird bones – provides a good combination of strength and weight.

The base’s design was guided in turn by the properties of 3D-printed lunar soil, with a 1.5 tonne building block produced as a demonstration.

1.5 tonne building block
1.5 tonne building block

“3D printing offers a potential means of facilitating lunar settlement with reduced logistics from Earth,” added Scott Hovland of ESA’s human spaceflight team.

“The new possibilities this work opens up can then be considered by international space agencies as part of the current development of a common exploration strategy.”

“As a practice, we are used to designing for extreme climates on Earth and exploiting the environmental benefits of using local, sustainable materials,” remarked Xavier De Kestelier of Foster + Partners Specialist Modelling Group. “Our lunar habitation follows a similar logic.”

Multi-dome base being constructed
Multi-dome base being constructed

The UK’s Monolite supplied the D-Shape printer, with a mobile printing array of nozzles on a 6 m frame to spray a binding solution onto a sand-like building material.

D-Shape printer
D-Shape printer

3D ‘printouts’ are built up layer by layer – the company more typically uses its printer to create sculptures and is working on artificial coral reefs to help preserve beaches from energetic sea waves.

“First, we needed to mix the simulated lunar material with magnesium oxide. This turns it into ‘paper’ we can print with,” explained Monolite founder Enrico Dini.

“Then for our structural ‘ink’ we apply a binding salt which converts material to a stone-like solid.

“Our current printer builds at a rate of around 2 m per hour, while our next-generation design should attain 3.5 m per hour, completing an entire building in a week.”

Britain Adds Funds to Repurpose ESA ATV as Orion Service Module

European Space Agency (ESA) Automated Transfer Vehicle (ATV)
Image Credit: ESA / CNES / Arianespace / Photo optique video du CSG

The European Space Agency (ESA) announced they will inform NASA they are ready to build an ATV derived Service Module for Orion, to be ready for the first launch of the Space Launch System (SLS) in 2017. The announcement came after the UK stepped up with additional funding, marking the country’s first real human Beyond Earth Orbit (BEO) commitment.

More Planets than Stars – But Axial Tilt may be the Key to Life

There is an average of more than one planet per star in the Milky Way
Image Credit: NASA / ESA / ESO

With the forthcoming publication in the journal Nature on 12 January, it is estimated that there are more than 100 billion planets in our Milky Way galaxy. That means more than one planet per star, and results show that there are more rocky small Earth-like planets than giant Jupiter-size gas planets.

Most recent discoveries have come from the Kepler Observatory using transit observations. Some of the earliest confirmation of gas giants came from radial velocity Doppler observations.

The conclusions in the Nature article are based on micro-lensing studies.

Recent results from the Kepler Observatory have shown the existence of three small, rocky planets around the star KOI-961, a red dwarf. These three planets, named KOI-961.01, KOI-961.02 and KOI-961.03, are 0.78, 0.73 and 0.57 times the radius of Earth. The smallest is about the size of Mars (see below). Follow-up observations were made by the Palomar Observatory, near San Diego, and the Keck Observatory atop Mauna Kea in Hawaii.

Relative size of the three rocky planets around KOI-961
Image Credit: NASA / JPL-Caltech

Since it is now clear that rocky planets exist around millions, if not billions, of stars, the question arises as to whether there is life on them, and whether it may resemble life on Earth.

Whether a planet exists in the “Goldilocks” region around a star depends on many factors. Three factors include the type of star, how far away from the star the planet resides and the atmospheric pressure of the planet. A red dwarf, such as Gliese 581, means the planet has to be closer than the Earth to our Sun. A white hot star means the planet has to be farther away. And if the atmosphere is low, like Mars, or to high, like Venus, liquid water is not likely.

A fourth factor is axial tilt. If a planet has no axial tilt (the spin axis is perpendicular to the plane of its orbit around the star) then the polar regions freeze and the equatorial regions bake. There is little exchange between these regions due to atmospheric circulation. Axial tilt, such as the Earth has, allows distribution of heat between the equator and the poles.

Even if a planet has axial tilt, a recent study shows that interaction at a close distance (within the “Goldilocks” region) with red dwarf will eliminate axial tilt in less than 100 million years. Bacteria on Earth required 1,000 million years to evolve. Theoretically, a planet with no axial tilt could possess bands between the equator and the poles where liquid water would exist. But, it is quite possible the atmosphere would collapse, with gases being driven off into space at the very hot equator, and freezing solid on the ground at the poles. Such a possibility faces the planets around KOI 961.

Systems with stars like our Sun present better possibilities. The “Goldilocks” conditions exist much farther out, and axial tilt is eliminated much more slowly, as our Earth is witness. Systems such as Kepler-22b are good candidates.

The conclusion drawn from these studies is that systems similar to our Solar System present the best opportunities for life.

Japan and Support of the International Space Station

Previously, we looked at the Europeans Space Agency (ESA) and their ATV program, which is preparing to send their resupply spacecraft, Johannes Kepler, to the International Space Station on 15 February.

Now, we look at the Japanese Aerospace Exploration Agency (JAXA) and the recently completed launch and capture of the Kounotori spacecraft.

HTV-2 "Kounotori"
Image Credit: Japan Aerospace Exploration Agency (JAXA)

The external exposed cargo includes a Flex Hose Rotary Coupler and Cargo Transport Container. These spare parts will be transferred to External Logistics Carrier 4 after it is installed during the Discovery STS-133 mission.

The pressurized cargo space is carrying 2,928 kilograms of supplies and equipment:

  • 630 kilograms of crew provisions
  • 1,626 kilograms of research equipment and supplies
  • 609 kilograms) of station hardware
  • 49 kilograms of computers and supplies
  • 14 kilograms of spacewalking equipment and supplies

Among the new research equipment will be the Japanese Kobairo gradient heating furnace for generating high-quality crystals from melting materials, an Amine Swingbed technology demonstration that will look at ways to revitalize the air on space vehicles, and the International Space Station Agricultural Camera, which will take frequent images, in visible and infrared light, of vegetated areas on the Earth.

Canadarm2 Captures HTV2
Image Credit: NASA

Hatch Open
Removing cargo through the hatch on HTV2
Image Credit: JAXA