Imagine this: We're on the cusp of potentially rewriting the history books, all thanks to some rocks from Mars! But before we get ahead of ourselves, let's dive into the fascinating preparation underway as we eagerly await the arrival of Martian samples on Earth.
Mars, our rusty neighbor, wasn't always the desolate desert we know today. Billions of years ago, it was a different story. Picture this: Jezero Crater, once home to a vast river delta and a body of water, perhaps the size of Lake Constance. This environment may have been conducive to life.
For over four years, the Perseverance rover has been tirelessly working in the long-dry Jezero Crater. This robotic explorer isn't just taking pretty pictures; it's also been collecting 33 precious rock, soil, and atmospheric samples. These samples are safely stored, awaiting a future mission to bring them back to Earth.
Could these samples hold the key to discovering life beyond Earth?
Recently, the Jezero Crater made headlines with the discovery of leopard-like patterns on a rock formation called Cheyava Falls. These intriguing structures suggest the presence of two minerals potentially of organic and microbial origin. These minerals are also found on Earth in sediments or decaying organic matter. But here's where it gets controversial: Only by analyzing these structures on Earth can we confirm, with a high degree of certainty, whether they indicate past life on Mars.
"Examining rocks and samples of the Martian atmosphere on Earth will open a new chapter in Mars research and help us understand our neighboring planet much better than we can today," says Andreas Pack from the Geosciences Center at the University of Göttingen.
Over the past two years, a collaborative effort between NASA and the European Space Agency (ESA) has involved an international team of 21 researchers. They've been meticulously planning how to handle Perseverance's samples from a scientific standpoint once they arrive on Earth. This comprehensive study has been published in the journal Astrobiology.
Among the authors selected by NASA and ESA, representing the US, Canada, and the 22 ESA member states, are Christian Schröder from MPS and Pack from the Geosciences Center at the University of Göttingen, the only representatives from German research institutions. NASA recently honored the team with the NASA Group Achievement Award. Another report in the same journal explores how to protect the Mars samples from terrestrial contamination, with Christoph Burkhardt from MPS as a co-author.
The Quest for Certainty: Laboratory Tests
The samples collected by the Perseverance rover are packed with valuable information about Mars' formation and evolution. They could finally help us answer the age-old question: Was there ever life on our neighboring planet? While Perseverance's onboard instruments offer clues, they can't provide definitive answers.
"In order to assess with the greatest possible certainty whether life once existed on Mars, we need to bring samples from Mars back to Earth and examine them here," explains Schröder, MPS scientist and co-author of the new study.
Earth-based laboratories offer a vast array of analytical methods, allowing for measurements with unparalleled sensitivity and precision.
For their current report, 21 scientists have identified which measurements the Mars samples should undergo to unlock their full potential. They hope to gain new insights into the formation of planets, the geophysical and geochemical evolution of Mars, and astrobiology, which will also provide valuable information for future, possibly even manned, Mars missions.
The report also addresses practical questions, such as which measurements should be prioritized. Some sample properties could change once the sample tubes are opened, for example, under the influence of humidity and oxygen. The report also addresses which measurements can definitively confirm or rule out the existence of life or any potential biological hazards.
The Sample Receiving Facility: A Hub of Discovery
Once the Martian samples arrive on Earth, they will first enter the Sample Receiving Facility. Experts recommend equipping it with 18 scientific instruments, including an X-ray tomograph, an electron microscope, and various mass spectrometers.
At the facility, scientists will initially describe and catalog the samples and assess any potential biological hazards. Then, all time-critical investigations can be carried out. An important finding of the report is that most of the scientifically necessary measurements should be conducted later in specialized laboratories outside the Sample Receiving Facility.
A competitive application process will determine which laboratories worldwide will receive portions of this invaluable material, ensuring the samples end up in the most experienced and qualified hands. The Göttingen researchers are hoping to receive both rock and gas samples from Perseverance.
Peering into the Past: A Look at Isotopes
Researchers led by Pack from the Geosciences Center at the University of Göttingen want to determine the proportions of oxygen isotopes in the Martian atmosphere that were trapped in the sample tubes with the rocks. Isotopes are different forms of the same element, differing only in the number of neutrons in their nuclei. The oxygen isotope composition of the Martian atmosphere can reveal information about the exchange of carbon dioxide between the surface and the atmosphere, providing insights into the climatic development of Mars.
At MPS, the focus is on the metal isotopes in the rock samples. Researchers can use them to determine the age of the material, its origin within the solar system, and how it has evolved. MPS researchers have previously examined samples from the asteroid Ryugu using this method.
The process involves dissolving the material in acid and then analyzing it using highly specialized mass spectrometers. Since this method destroys the sample material, obtaining reliable results from even the smallest amounts of material is crucial.
"In Göttingen, we have the expertise and infrastructure to analyze Mars samples at the highest international level," says Thorsten Kleine, Director at MPS.
Researchers could carry out further investigations at other facilities. Schröder, for example, is focusing on measurements using high-energy gamma radiation generated by particle accelerators. This would allow them to trace the interaction of iron minerals in the sample with organic material.
The Uncertain Future: When Will the Samples Arrive?
Whether and when the Mars samples from Perseverance will be brought to Earth as part of a joint NASA and ESA mission is currently uncertain. The original schedule targeted the early 2030s, but it has been adjusted multiple times. However, the studies now published are also valuable for the projects of other space agencies. For example, the Chinese space agency is preparing its own sample return mission to Mars, which is expected to bring the coveted material back to Earth as early as 2030.
So, what do you think? Are you excited about the possibility of finding life on Mars? What questions do you have about the process? Share your thoughts in the comments below!
