Scientists are doing ground-based experiments on life support systems so that humans can explore space and one day live outside the Earth's biosphere, for example on Mars or on the Moon.

Mark Nelson, a leading expert from the United States, said at the ongoing 36th Committee on Space Research Scientific Assembly that the experiment simulates a four person sustainable life support system designed for Mars.

Nelson said that researchers have termed the project "Mars on Earth". They stress that substantial work needs to be carried out on Mars life support prototypes here on Earth before scientists will have the data base, confidence and ability to undertake similar projects in space or in lunar/Martian conditions.

The US laboratory being used for the experiment, which covers an area of approximately 800 square meters, is located in Santa Fe, New Mexico. Scientists there are developing life support systems for space, such as water and waste water recycling, food production and air purification, and are also developing space engineering and technology for the Mars Base, Nelson said.

Scientists aim to produce a complete diet in the lab and to recycle all waste products including human waste from the crew in the closed system.

The diet chosen for the experiment utilizes ten crops including rice, wheat, sweet potato, peanut, soybean, pinto bean, winter squash, beetroot, banana and papaya, said Nelson.

They are hardy, dependable and relatively easy to harvest and process with a minimum of equipment, the scientist said.

Nelson is the director of Space and Environmental Applications for Space Biosphere Ventures, which created and operated Biosphere 2, the 3.15 acre closed facility near Tucson, Arizona, the world's first global ecology laboratory.

He was a member of the eight person "biospherian" crew for the first two year closure experiment, 1991 to 1993.

Compared with the biosphere system of the Earth, Biosphere 2 aimed to be a self-contained research lab for global ecology, with its own atmosphere, rain forest, ocean, savannah, farm and housing. The crew raised its food and recycled air, water and waste.

However, the United States media claim that Biosphere 2's 1990s experiments were not very successful.

"Like any experiment, Biosphere 2 had unexpected occurrences, like a decline in atmospheric oxygen," Nelson told Xinhua.

"We learned a lot from Biosphere 2 about Earth ecosystems and the integration of technology with life systems," Nelson said, adding that the lessons learned from Biosphere 2 were being used in their current experiments.

"Once the facility has demonstrated that a biospheric life support system is feasible and is desirable for humans to inhabit, a human future in space will become a real possibility," Nelson said.

"This investigation into life support systems will not only yield data for space exploration but also information that can be used to understand and preserve the ecological health of our own planet," said Nelson.

He said that ground-based experiments with a wide variety of approaches and with varying technological support strategies are not premature, but essential if human space exploration and habitation outside the Earth's biosphere is to be viable in the future.

"There are a number of unsolved issues before we can successfully create balanced, sustainable and completely bioregenerative life support systems on Earth and have the confidence to apply them step by step in space," he said.

He said that if people are genuinely determined to live on Mars, then they will be able to achieve that goal.

"If the international community commits the resources, it could be done in 15-20 years," Nelson said.

"But we will need to do a lot of ground-based research on prototype systems to prepare properly for such applications in space," he added.

(Xinhua News Agency July 21, 2006)