One of the persistent challenges of manned space exploration is that pesky lack of oxygen throughout much of the universe. Here on Earth, trees and other plant life do us a real solid by taking in our bad breath and changing it back to clean, sweet O2.

So what if we could take those biological oxygen factories into space with us, but without all the land, sun, water, soil, and gravity that forests tend to require? This is the point where NASA and Elon Musk should probably start paying attention.

Royal College of Art graduate Julian Melchiorri has created the first man-made, biologically functional leaf that takes in carbon dioxide, water, and light and releases oxygen. The leaf consists of chloroplasts -- the part of a plant cell where photosynthesis happens -- suspended in body made of silk protein.

"This material has an amazing property of stabilizing (the chloroplast) organelles," Melchiorri says in the video below. "As an outcome I have the first photosynthetic material that is living and breathing as a leaf does."

In addition to its potential value to space travel, Melchiorri also imagines the technology literally providing a breath of fresh air to indoor and outdoor spaces here on Earth. The facades of buildings and lampshades could be made to exhale fresh air with just a thin coating of the leaf material.

But perhaps best of all, a man-made breathing leaf could be the key to not just space travel but space colonization. No need to figure out how to till that dry, red Martian dirt to get some nice leafy trees to grow; we could just slap them on the inside of the colony's dome and puff away.