Sci-fi storytellers love to tell tales of laser-wielding aliens visiting Earth — but in reality, we’re the ones who are now using sophisticated laser beams to search for signs of extraterrestrial life.
University of Maryland geologists and engineers recently developed new technology, designed for flying in space, that uses light to analyze molecules. This work, published last week in natural astronomy, takes a common molecular analysis laboratory instrument here on Earth, known as an orbitrap, and downsizes it to make it compact and light enough to fit on a NASA mission to the solar system. They also combine the upgraded Orbitrap with a laser that can break up material from a planet’s surface to prepare it for analysis.
“I’m excited to see what kind of complex molecules we can detect beyond Earth,” says Grace Ni, a University of Maryland geologist and co-author of the study. “The next-generation Orbitrap analyzer offers about 200-fold improvements” in the detail of its measurements compared to older systems, she adds. It could fly on missions within the next decade.
The Orbitrap is a tool for mass spectrometry, a go-to technique for scientists that separates molecules by their mass and measures how much of each is present in a sample. Though these machines can be found in medical, biological, and other industrial laboratories around the world, they’re also huge, weighing around 400 pounds — slightly heavier than a giant panda. Offworld missions are often limited in the amount they can carry to their destinations. One of those gigantic orbitraps just wouldn’t fly. However, the new version only weighs about 17 pounds.
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Also, mission teams often have to choose between one large component or several smaller tools. Selecting instruments for a space mission is “like selecting the tools you want on your Swiss army knife,” explains Zach Ulibarri, an aerospace engineer at Cornell University who was not part of the new study. “But at the same time, the tools on a Swiss Army knife are smaller and lighter than the tools you keep in your garage, just like the instruments on your spacecraft need to be smaller and lighter than the full-size ones you keep in a lab.”
Before it can measure a molecule, the improved laser device uses ultraviolet pulses to break the bonds from a planet’s surface – like rocks on Mars, the icy outer shell of Enceladus or other interesting targets for possible life in our solar system. It then directs them into the miniaturized Orbitrap spectrometer, where the composition of the sample is measured.
Eddie Schweiterman, a University of California Riverside astrobiologist who isn’t involved with the new Orbitrap project, explains that this tool will take the “fingerprints” of life-related molecules while also providing information about the surrounding geology of the planet or moon being explored. Context is key for life signs — scientists must be able to rule out non-living sources of the same life-like chemicals. This new laser orbitrap system would also allow scientists to perform this detailed chemical analysis remotely via a simple robotic mission like a lander or rover, as opposed to returning samples to Earth.
While there’s a lot of work to be done to detect biosignatures on distant exoplanets, it’s a very different ball game than exploring the solar system with a probe via an enhanced orbitrap. The large organic molecules that Orbitrap missions aim to analyze “can’t be easily observed from a distance, especially at interstellar distances,” says Schweiterman. Instead, exoplanets can only be observed with our telescopes from light years away. But astronomers could send robots equipped with this tool to the surfaces of the planets closest to us.
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There’s also a catch. The large amount of data generated by the new system “could cause headaches in data storage and transmission during a space mission,” Ni said. Hopefully, with the inevitable advancement of computer technology, engineers will find clever ways to deal with this problem. Even then, data storage isn’t a dream killer for the Orbitrap – just another thing to consider when designing a spacecraft. As Ulibarri says, “Each instrument has its own pros and cons. There is no perfect instrument; there are only compromises between different ones.”
Building a fully functional spacecraft is always difficult, but new instrument technologies such as the improved Orbitrap expand the possibilities for future missions. “It’s always exciting to add a new tool to the potential spacecraft toolbox,” says Ulibarri. “And the Orbitrap is a particularly powerful tool.”