Dr. Afshin Khan: Crops on Mars
by Emily Harari
Every 4th of July, many Americans turn their gaze to the night sky. From a pop of color and a quick clap like thunder, fireworks unveil themselves. In addition to gunpowder, a lesser known ingredient called perchlorates are responsible for the mesmerizing explosions. Perchlorates are salts containing an ion called perchlorate – a chlorine atom bonded to four oxygen atoms. These salts can serve as oxidants for fireworks and explosives, but also can be toxic to living things. These volatile compounds are also found on the surface of Mars, but that hasn’t discouraged Dr. Afshin Khan from someday growing crops there.
While she theorizes how to bring life to other planets, Dr. Khan’s current research at NASA’s Jet Propulsion Laboratory is quite the opposite. Just before the launch of a spacecraft, she’ll inspect it for signs of life. No matter how microscopic, every living thing must be removed. This process is called spacecraft sterilization and it’s essential to planetary protection, the idea that space travel should not contaminate other planetary bodies with Earth life (or vice versa). That way, a hitchhiker from Earth won’t be mistaken for extraterrestrial life.
As public and private collaborations promise more launches in the near future, ideas to sustain humans in space gain popularity. Meanwhile, Khan is no stranger to industry applications for science. When she was a PhD student at Washington State University in Pullman, Washington, she traveled to Silicon Valley and trained at Singularity University, where she developed a horticulture startup company.
Since catching the Silicon Valley bug, she combined her scientific curiosities with business acumen. She founded Chimeric Designs, a precision-medicine company for cancer immunotherapy. She wanted to return to agriculture technology, but not for growing on Earth. She and her team developed a business proposal for studying crops grown in space. Their project, SustainSpace, won the 2017 Space Exploration Masters competition hosted by the European Space Agency (ESA). In addition to space life support systems, the multifaceted project was awarded for its applications in STEM education and agriculture research and industry.
From her entrepreneurial escapades, Khan strikes a balance between imagination and practicality which guides her current research to grow crops on Mars. Space travel companies are working to bring humans to space, but Khan is more interested in how to sustain humans once they get there. “What about resupply missions?” she asks. Rather than rely on multiple, costly shipments of dehydrated foods, Khan believes that growing crops in outer space is a more cost-effective solution.
Shortly after earning her PhD, she returned to her alma mater for NASA’s CubeSat Launch Initiative. With the university’s group, Cougs in Space, Khan made a satellite box designed to grow pea plants in space from just a few seeds inside. Without relying on astronauts to tend to the seeds, the box will stream back data on whether or not the experiment works. It’s launch date is set for May 1, 2021.
CubeSat got Khan thinking more about automation and how to scale the technology. “If we are going to send people to Mars,” muses Khan, “maybe [we should] send some missions beforehand… to set up a greenhouse or have those crops ready to go.” Before SustainSpace and CubeSat, she translated this vision into an autonomous greenhouse for S. Home. Khan and her interns at Blue Marble Space Institute of Science (BMSIS) designed a Martian habitat to sustain six astronauts for 600 days.
Khan now sets her sights on technology that could sustain life on Mars for more people and for much longer. Her long-term solution requires bringing Martian soil into the greenhouse. “It should be easy to scale if you’re [growing crops] in the Martian soil… because then you’re just using the local resources,” explains Khan. She was inspired by the ESA’s MELiSSA Project, which mimics Earth’s closed ecological systems to renew and replenish resources. For example, humans generate waste, which fertilize plants, which feed humans, and the cycle repeats.
However, those pesky perchlorates that can allow for illuminating firework displays also stand in the way of Khan’s Martian farm-to-table vision. The toxic compounds which normally combust with heat are stabilized on the regularly below-freezing Martian surface and they’re abundant in Martian regolith. Regolith is coarse and sandy, and unlike Earth soil, it lacks nutrients and microbes that plants need to grow. This summer, Afshin’s new BMSIS interns are researching which bacteria and fungi from Earth they can add to Martian regolith in order to transform it into Earth-like soil.
Some microbes from Earth can remove toxins like perchlorates. They may even eliminate the toxic compounds from Martian regolith. But until that day, Dr. Afshin Khan can look up at the sky each 4th of July and admire the perchlorates. Because just beyond the fireworks, her pea plants may soon grow in orbit and someday do the same on Mars.
Emily Harari is a science communicator. She studied molecular and cell biology at UC Berkeley and has enjoyed working in biotechnology startups. She aspires to promote trust and progress in biotech by applying her research experience and writing skills.