Big Results Sought From ‘Mini Earth’

Masanori Shinohara was working as a researcher studying dolphin behavior when his wife commented on a newspaper ad seeking scientists to populate a “mini Earth.”

Shinohara began checking into it. “It sounded interesting, but I couldn’t figure out what it was about” at first, he says

It turned out to be a Japanese version of the ballyhooed, but far-from-successful, Biosphere 2 experiment in the early 1990s in which eight scientists were sealed in a compound in Oracle, Ariz.

Shinohara was intrigued, applied for a spot and was selected.

He’s counting down the months until he and chemist Osamu Komatsubara become the first human residents in 2005 at the facility erected in Rokkasho, a small farming and fishing town on Japan’s northern coast.

Mini Earth is less ambitious than the 3.15-acre, $200-million Biosphere 2, which had its own ocean, desert, savanna and rainforest.

With a construction budget of $65 million, the 1.16-acre Mini Earth was completed two years ago. Researchers have since been doing preliminary experiments inside the compound, which consists of three gymnasium-sized buildings connected by stainless-steel corridors.

The project calls for the two scientists to be sealed off with animals and plants in the air-locked structure for about a week at first, then for stretches of up to five months.

The goal is to simulate the cycle of oxygen and carbon dioxide among plants, humans and animals in a sealed environment.

Along with providing insights into the cycles and interactions themselves, the perfecting of self-sustaining environments could have important applications in the exploration of space and oceans.

One of the problems that plagued Biosphere 2 was the consumption of oxygen.

Though intended to be a self-sustained, self-contained living system, oxygen had to be pumped into Biosphere 2 because microbes in its soil consumed oxygen faster than the plants inside could produce it. The facility’s concrete walls also trapped carbon dioxide, impeding the growth of plants.

Keiji Nitta, a rocket scientist and senior executive director at the Institute for Environmental Sciences, which supervises Mini Earth, says he is confident that won’t be a problem in Japan’s project.

“One of the big differences from Biosphere 2 is that we put a lot of money and time into designing and making our life-support system,” Nitta said.

Instead of using soil and relying on microbes, Mini Earth has machines to artificially decompose and process waste materials. The artificial support section takes up a quarter of the facility’s total floor space.

A central part of the backup system is the oxygen-recovery processor, which retrieves oxygen from carbon dioxide by using high temperature and water electrolysis.

Nitta said the machinery to be used in Mini Earth is more efficient than similar equipment being developed by NASA for use in the international space station. “I think that technologies developed here will be used in space in the future,” he said.

In the living quarters for the scientists, there are two beds, computers and a stationary bike. A television camera is mounted in a corner of the room to check on their safety.

Animals will be kept in an adjacent room. Two goats were recently kept there for three weeks to monitor their stress levels, temperatures and hearts to determine if they are fit for a closed environment.

For food, the researchers have tried planting about 30 kinds of vegetables and rice in rooms where the temperature, humidity and light are controlled.

Only electricity and information will be provided from outside. Communication with the outside world will be through phones, e-mail and the Internet.

Although scientists agree on the general merit of Mini Earth-type experiments, some question what Japan might be able to do with the research.

“The most practical goal for closed-environment experiments would be to build a station on the moon, but it would be difficult for Japan to build one on its own,” said Nobuyuki Tomita, professor of space system engineering at Musashi Institute of Technology in Tokyo, who is not associated with the project.

He added, however, that know-how gleaned from the Mini Earth project might be useful for building living spaces for people who work under water, below ground or in severe weather conditions.