Making the Search for Mars Life Easier

Categories: Also in News Mars

Using an ion Funnel could improve mass spectrometry techniques on future Mars rovers. Credit: Pacific Northwest National Laboratory


In a recent paper published online in the journal Planetary and Space Science, a team of researchers propose adding a laser and an ion funnel to a widely used scientific instrument, the mass spectrometer, to analyze the surfaces of rocks and other samples directly on Mars‘ surface. The researchers demonstrated that the combined system could work on the spot, without the sample handling that mass spectrometry usually requires.

"There are a lot of exciting discoveries about Mars that have yet to be made," said the paper’s lead author, Paul Johnson. "This technique could make understanding the composition of rocks and soils on Mars — possibly including evidence of life — much easier."

Johnson, of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., came up with the idea after reading about an ion funnel technology for mass spectrometry developed by Keqi Tang and Dick Smith of the Department of Energy’s Pacific Northwest National Laboratory. William Brinckerhoff of NASA’s Goddard Space Flight Center in Greenbelt, Md., contributed his expertise in miniaturizing scientific instruments to the project, while Robert Hodyss, also of JPL, provided hands-on expertise during experimentation and testing.

Here on Earth, mass spectrometry is a common analytical technique scientists use to identify molecules, their elements and their isotopes in samples ranging from rocks to proteins. It works by turning a sample’s molecules into electrically charged ions. A mass spectrometer then precisely measures the mass of ions and ion fragments to identify the sample’s contents at a detailed molecular level.

Mass spectrometry isn’t new to space exploration. It was used to analyze Martian soil for the first time as part of NASA’s Viking program in the 1970s. And it’s planned to be part of the Mars Science Laboratory’s Curiosity rover, which will lift off for the red planet this November. But each time it’s been used in space, the samples had to be extensively prepared before they could be analyzed.


This photograph by Viking 1 is the first ever taken on the surface of Mars. Viking used mass spectrometry to analyze soil on Mars. Credit: NASA

On Earth, scientists do mass spectrometry within a vacuum chamber. But that requires either finding a small enough sample, or cutting down the sample to fit into the chamber. Any such efforts on Mars have to be done with a robotic rover that’s controlled by human operators millions of miles away.


Trying to simplify this work, Johnson and Hodyss at JPL, which manages NASA’s Mars Exploration Project, turned to a technique called laser ablation. The method involves shooting a laser at the sample’s surface, which creates a plume of molecules and ions that can then be analyzed by the mass spectrometer.



"We didn’t specifically design the ion funnel for space exploration, but we’re excited that it and Mars are a good fit," said Tang.

Mass spectrometry will also play a role in the upcoming Mars Science Laboratory mission. Credit: NASA/JPL-Caltech

JPL asked PNNL to help test whether the combination of laser ablation and an ion funnel could make in situ, or "in place," mass spectrometry possible on Mars. A standard laboratory mass spectrometer was equipped with laser and an ion funnel attachments, and the ion funnel end was placed inside a sealed chamber that matched Mars’ atmospheric conditions. The researchers shot laser pulses at various samples, such as copper, stainless steel and gypsum. As they suspected, a small layer of each sample’s surface atoms was transformed into ions and the ion funnel quickly pulled them into the mass spectrometer, which identified the samples.

"This system could be developed into a ‘point and shoot’ instrument for space analysis," Johnson said


Funded by NASA, the team performed their experiments at JPL, which is managed by the California Institute of Technology. The ion funnel they tested was developed and constructed at EMSL, the Department of Energy’s Environmental Molecular Sciences Laboratory on PNNL’s campus.