In Space Pee Is for Power

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Country Email Country * Afghanistan Aland Islands Albania Algeria Andorra Angola Anguilla Antarctica Antigua and Barbuda Argentina Armenia Aruba Australia Austria Azerbaijan Bahamas Bahrain Bangladesh Barbados Belarus Belgium Belize Benin Bermuda Bhutan Bolivia, Plurinational State of Bonaire, Sint Eustatius and Saba Bosnia and Herzegovina Botswana Bouvet Island Brazil British Indian Ocean Territory Brunei Darussalam Bulgaria Burkina Faso Burundi Cambodia Cameroon Canada Cape Verde Cayman Islands Central African Republic Chad Chile China Christmas Island Cocos (Keeling) Islands Colombia Comoros Congo Congo, the Democratic Republic of the Cook Islands Costa Rica Cote d’Ivoire Croatia Cuba Curaçao Cyprus Czech Republic Denmark Djibouti Dominica Dominican Republic Ecuador Egypt El Salvador Equatorial Guinea Eritrea Estonia Ethiopia Falkland Islands (Malvinas) Faroe Islands Fiji Finland France French Guiana French Polynesia French Southern Territories Gabon Gambia Georgia Germany Ghana Gibraltar Greece Greenland Grenada Guadeloupe Guatemala Guernsey Guinea Guinea-Bissau Guyana Haiti Heard Island and McDonald Islands Holy See (Vatican City State) Honduras Hungary Iceland India Indonesia Iran, Islamic Republic of Iraq Ireland Isle of Man Israel Italy Jamaica Japan Jersey Jordan Kazakhstan Kenya Kiribati Korea, Democratic People’s Republic of Korea, Republic of Kuwait Kyrgyzstan Lao People’s Democratic Republic Latvia Lebanon Lesotho Liberia Libyan Arab Jamahiriya Liechtenstein Lithuania Luxembourg Macao Macedonia, the former Yugoslav Republic of Madagascar Malawi Malaysia Maldives Mali Malta Martinique Mauritania Mauritius Mayotte Mexico Moldova, Republic of Monaco Mongolia Montenegro Montserrat Morocco Mozambique Myanmar Namibia Nauru Nepal Netherlands New Caledonia New Zealand Nicaragua Niger Nigeria Niue Norfolk Island Norway Oman Pakistan Palestine Panama Papua New Guinea Paraguay Peru Philippines Pitcairn Poland Portugal Qatar Reunion Romania Russian Federation Rwanda Saint Barthélemy Saint Helena, Ascension and Tristan da Cunha Saint Kitts and Nevis Saint Lucia Saint Martin (French part) Saint Pierre and Miquelon Saint Vincent and the Grenadines Samoa San Marino Sao Tome and Principe Saudi Arabia Senegal Serbia Seychelles Sierra Leone Singapore Sint Maarten (Dutch part) Slovakia Slovenia Solomon Islands Somalia South Africa South Georgia and the South Sandwich Islands South Sudan Spain Sri Lanka Sudan Suriname Svalbard and Jan Mayen Swaziland Sweden Switzerland Syrian Arab Republic Taiwan Tajikistan Tanzania, United Republic of Thailand Timor-Leste Togo Tokelau Tonga Trinidad and Tobago Tunisia Turkey Turkmenistan Turks and Caicos Islands Tuvalu Uganda Ukraine United Arab Emirates United Kingdom United States Uruguay Uzbekistan Vanuatu Venezuela, Bolivarian Republic of Vietnam Virgin Islands, British Wallis and Futuna Western Sahara Yemen Zambia Zimbabwe Right now, astronauts on board the ISS filter wastewater and then distill it to recover pure water, says Layne Carter, a systems engineer at NASA’s Marshall Space Flight Center in Huntsville, Alabama, who is in charge of the space station’s water systems (and who is not involved in the new study). Current processes, he notes, recover only 75% of the water from urine. But with efforts now under way, NASA engineers hope to increase that percentage to 85% next year and then to nearly 100%.The space station’s current recycling process disposes of urea, the main nitrogen-rich compound in urine, Nicolau says. But urea can be used to make power, and now Nicolau and colleagues have developed a technique that may simultaneously use urea to improve the efficiency of recycling a spacecraft’s wastewater.In the first step, the researchers used osmosis—a process in which some substances pass through a membrane—to separate large organic molecules from the water, urea, and other small dissolved molecules or atoms, which pass through the membrane into a salty solution.Then the researchers forced the urea-laden solution through a device they call a bioreactor, which is packed with activated charcoal that’s been soaked with urease, the enzyme that breaks down urea. In that step of the lab tests, about 86% of the urea is converted into ammonia, the researchers report in the 7 April issue of ACS Sustainable Chemistry & Engineering.Finally, the ammonia is collected and fed into a batterylike fuel cell, which converts the ammonia into nitrogen and water, emitting power. In the tests, the amount of electrical power generated is small: Voltages are about 0.2 volts, and currents about 2 milliamps, Nicolau says. But the team hopes to improve the power output in its next version of the system, he says.“This sounds like a clever process, but I’m skeptical about whether it will work at a larger scale or in the uncontrolled environment of space,” says Carter, who has worked on wastewater systems at NASA for 25 years. He also notes that urea is a relatively small component of urine, so the limited amount of power that might be harvested from the team’s new process might not recoup the effort or expense.“This [process] definitely sounds complicated,” he says. “I wonder if the payback would be worth it.” Urine is typically considered something to get rid of. But urine is largely water, and that’s a valuable resource in space. If a new process can be successfully scaled up from recent lab tests, future space travelers could more efficiently recycle their own urine to reclaim its water and make a little electrical power to boot.Getting water and other supplies to the International Space Station (ISS) is expensive. It costs about $33,000 per kilogram to launch materials into low-Earth orbit, says Eduardo Nicolau, an analytical chemist at the University of Puerto Rico, Rio Piedras. Launching them higher is even more costly. Resupplying spaceships carrying people far outside Earth’s orbit—to Mars, say—probably would be prohibitively expensive even if possible.Thus, Nicolau says, crews of long-term space missions will have to recycle their water. And the biggest source of that water is their own urine. Each astronaut on such a mission will likely produce more than 1.5 liters each day, accounting for more than 81% of the spacecraft’s wastewater, Nicolau estimates. Click to view the privacy policy. Required fields are indicated by an asterisk (*)