In 2030, Will Martian Life Invade Earth? [Reading Science]

NASA and ESA to Launch Mars Sample Return Program Targeting Early 2030s
China Also Plans to Retrieve 'Zhurong' Samples by 2030
Some Scientists Concerned About Unpredictable Lifeforms Contaminating Earth

[Image source=Yonhap News]

[Asia Economy Reporter Kim Bong-su] The 2005 film "War of the Worlds" depicted an alien invasion. As a staple theme in sci-fi movies and science fiction novels, it is a story that easily instills fear in humanity, which has yet to confirm the existence of extraterrestrial life. However, recently, voices warning about the possibility of "Martian organisms" invading and contaminating Earth have been emerging.

The United States National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA) are promoting the Mars Sample Return (MSR) project, which aims to transport rock, soil, and atmospheric samples collected by the Mars exploration rover Perseverance back to Earth by the early 2030s. Perseverance landed in Jezero Crater on Mars in February last year and is currently collecting rock, soil, and atmospheric samples using a drill attached to its 2-meter-long robotic arm, storing them in 43 special titanium containers.

This is a golden opportunity to study the existence of life on Mars, its geological structure and history, and the secrets of the solar system's formation, so much so that scientists regard it as a holy grail goal. NASA and ESA initially planned to transport the samples in two phases, in 2026 and the early 2030s, but the 2026 plan was canceled earlier this year due to budget and other reasons.

The problem is the raised possibility of Earth contamination by Martian microbes or Mars contamination by Earth microbes. There could be life forms on Mars in forms unknown to us, and there are concerns that leakage from the samples transported to Earth could lead to "terrible consequences." Many creative works, including films and novels, have explored such "imaginations." Representative examples include Michael Crichton's 1969 novel "The Andromeda Strain" (adapted into a film in 1971) and the 2005 sci-fi film "War of the Worlds," which depicts a Martian invasion of Earth. In fact, over the past several decades, many scientists worldwide, including those in the U.S., have expressed concerns that microbes possibly contained in Mars samples could contaminate Earth's ecosystem.

The U.S. National Academy of Sciences' Space Studies Board expressed such concerns in reports published in 1997 and 2009. The 1997 report stated, "Based on current information, the likelihood of life forms known to us existing on the surface of Mars is low," but added, "There remains a possibility that microbes exist in hydrothermal oases or underground." The 2009 report noted, "Some Earth organisms have demonstrated the ability to survive in extreme environments," and warned, "Samples transported from Mars should be treated as potential hazards and quarantined until their safety is confirmed. Sterilization of Mars samples and spacecraft exteriors is necessary."

Conversely, contamination of Mars by Earth's life forms during exploration, sample collection, and transport processes could also occur. In this regard, last October, the Space Studies Board issued guidelines for Mars exploration, stating that if equipment is designed to prevent unintended transfer of Earth microbes to Mars, a somewhat relaxed bioburden standard (the level and types of microbes that may be present) can be applied for rover exploration on Mars. This is because the extreme ultraviolet rays, high temperatures, and dry environment on Mars' surface make the survival of Earth microbes highly unlikely. However, the board did not rule out the possibility that microbes from Earth that happen to survive could spread across Mars by wind or rover movement or infiltrate underground to survive and reproduce. Especially, there may be caves containing ice and brine where life could survive underground on Mars, and groundwater is also expected in deeper areas. The report pointed out, "These areas could be places where evidence of indigenous Martian organisms might be found."

Regarding this, former NASA chief scientist John Rummel told the space-specialized media Space.com, "Earth life forms stuck to the underside of spacecraft and rovers that went to Mars could survive buried a few inches beneath the Martian surface when samples are collected," adding, "This could lead to Earth organisms returning to Earth being mistaken as originating from Mars."

Meanwhile, China's attempt to take the lead is also putting NASA in a difficult position. China plans to retrieve samples collected by the rover "Zhurong," which landed on Mars last May, by 2030 to confirm the existence of Martian life. China had already successfully transported samples collected by Chang'e 5 from the Moon to Earth in 2020. NASA and ESA are currently competing with China to be the first to retrieve Mars samples. Additionally, the global COVID-19 pandemic that began in early 2020 has heightened vigilance regarding microbes, adding another variable to the situation.