Concerns about virus outbreaks from Mars invading Earth

No one can be certain that Martian samples do not contain tiny organisms. If they do, no one can assert that they won’t pose a threat to Earth.

When envisioning sending humans to Mars in the book “Cosmos”, published in 1973, Carl Sagan raised a different issue beyond cost and complexity. Life may have once existed on the red planet and could have harmful effects on humanity.

“There may be pathogens on Mars. If organisms are brought into the human environment, they could cause a biological disaster, a Martian plague,” he wrote.

Scenarios where extraterrestrial samples contain dangerous organisms exemplify “back contamination,” or the risk of material from another planet harming Earth’s biosphere.

“The likelihood of such pathogens existing is probably very small, but we cannot accept any risk, even a small one, that could endanger a billion lives,” Sagan wrote.

Scientists have long considered Sagan’s warnings through various hypotheses. However, in the coming decade, they will begin taking concrete actions to address the risks of back contamination, according to the New York Times.

The Martian surface captured by the Perseverance rover. (Photo: NASA).

Special Mission

The National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA) are preparing for a joint mission named Mars Sample Return. The Perseverance rover is collecting samples on the red planet and will send them back to Earth via another spacecraft.

With concerns about back contamination, NASA must act as if Martian samples could cause another pandemic.

“Because the probability is not 0%, we are conducting assessments to ensure that contamination is not possible,” said Andrea Harrington, NASA’s Mars sample lead.

The agency plans to handle Martian samples similarly to how the Centers for Disease Control and Prevention (CDC) handles Ebola. Once the samples land on Earth, they must be kept in a facility known as a “Sample Receiving Facility.”

Mission experts state that the facility must meet “Biosafety Level 4” (BSL-4) standards, meaning it can contain the most dangerous pathogens known to science.

Andrea Harrington, NASA’s Mars sample lead. (Photo: New York Times).

At the same time, the facility must also prevent Earth material from contaminating Martian samples. If the mission proceeds as planned, the samples could land on Earth by the mid-2030s.

Building a facility that can safely contain Martian samples will take considerable time. Construction may also face political challenges or community opposition.

As of now, no laboratory meets NASA’s requirements. Therefore, a team of four scientists, including Dr. Harrington, has toured some of the most hazardous facilities on the planet.

They refer to themselves as the “NASA RAMA Tiger Team.” This nickname sounds like a military reconnaissance group, but in reality, it is just an acronym for the team members’ names.

The team has visited hotspots such as the National Emerging Infectious Diseases Laboratories in Boston, the U.S. Army Medical Research Institute of Infectious Diseases in Maryland, and CDC Building 18 in Atlanta.

In total, the research team has visited 18 facilities handling dangerous pathogens, clean rooms, and manufacturing sites for equipment serving both purposes. Team members hope to find suitable equipment for NASA’s facility to ensure maximum safety for humanity.

Potential Threat

“This will be the first mission to bring samples from another planet back to Earth. For the first time, another world will encounter humanity,” Harrington said.

Numerous samples from around the Solar System have been brought to Earth for study. Moon rocks and dust have come from missions by the U.S., the Soviet Union, and China. Samples from two asteroids were collected by Japan. Particles from solar winds and comets have been gathered by spacecraft.

However, material from Mars is considered by NASA to pose a “significant” risk of back contamination. Thus, samples from this planet fall under a legal category known as “Restricted Return to Earth.”

“We must treat those samples as if they contain hazardous biological materials,” said Nick Benardini, a planetary protection expert at NASA. Dr. Benardini oversees policies and programs aimed at preventing Earth bacteria from contaminating planets and moons in the Solar System while limiting space materials that could harm Earth.

Illustration of the Mars Sample Return mission. (Photo: ESA).

John Rummel, an expert who worked at NASA from 1987 to 2008, believes the space agency’s focus on risk is justified, even if the odds are very small and seem like science fiction.

“There are significant unknowns regarding biological factors. Mars is a planet. We don’t know how it operates,” he said.

Part of the Mars Sample Return mission is to understand how Mars functions. This has yet to be accomplished correctly because scientists and research equipment have not been able to reach there.

NASA’s Perseverance spacecraft arrived on Mars in 2021 and is currently collecting samples. These samples will be sent to a robotic lander or helicopter. A rocket will then launch the sample container into Martian orbit, where a European-built spacecraft will “catch” it and return to Earth.

According to the plan, by 2033, the samples will land in the Utah Test and Training Area. After that, scientists can study them with laboratory equipment.

Technological Challenges

The RAMA team’s job is to find ways to turn the risk of contamination into an opportunity. Their goal is to learn about clean rooms and what the space agency may need to invent.

The research team has visited seven high-level containment laboratories in the U.S., the U.K., Singapore, and ultra-clean space laboratories in Japan and Europe. The team has also visited equipment manufacturers serving laboratory needs.

The greatest technological challenge is that the sample receiving facility must serve dual purposes.

“Earth must not touch the samples, and the samples must not touch Earth,” said Michael Meyer, lead researcher for the Mars exploration program.

The storage facility must ensure that Earth substances do not contaminate Martian samples, preventing experiments from yielding false results. Simultaneously, the storage must keep Martian material contained, preventing it from escaping into the atmosphere.

Clean rooms require positive air pressure, meaning the pressure inside is higher than the pressure outside. Therefore, air always flows from the inside to the outside.

However, high-level containment laboratories operate in the opposite manner. They maintain lower air pressure inside than outside. Particulate matter can enter but cannot escape.

Illustration of robots used in the mission. (Photo: NASA).

NASA needs positive pressure space to keep samples clean while also requiring negative pressure to prevent samples from escaping. It is very difficult to integrate these conditions into the same space. It requires an innovative room structure and sophisticated ventilation systems.

No laboratory on Earth can achieve this at the scale required for the Mars Sample Return.

“We are not surprised that this does not exist,” Dr. Harrington said.

The best the RAMA team can do is observe how laboratories operate and hope to identify the best combination of solutions.

Inside BSL-4 laboratories, High-Efficiency Particulate Air (HEPA) filters are ubiquitous. The research team has explored sterilization methods, such as using Hydrogen Peroxide (H2O2) to eliminate contaminants on surfaces. However, the team still needs to find a suitable method to sterilize extraterrestrial material.

“Research to understand sterilization, in the case of these samples, is ongoing,” Dr. Harrington stated.

Regarding the structure, the floor, ceiling, and walls of the sample receiving facility can be coated with epoxy like BSL-4 and clean rooms typically do. The isolation room used by European scientists to build rovers uses stainless steel walls. Both materials can serve NASA’s dual purpose.

The RAMA team is also examining the equipment scientists use to handle Martian samples, allowing for precise manipulation of materials without direct contact. Scientists have previously studied substances in pure nitrogen environments, providing NASA with a potential consideration.

Emerging Issues

Many current laboratories are too small for the scale required by their missions. The size of the doors also significantly affects the ability to move equipment in and out.

Equipment brought into BSL-4 laboratories is not permitted to be removed, and may even need to be destroyed. As a result, these labs will have fewer measuring devices compared to a standard laboratory. Meanwhile, the Mars Sample Return mission requires a substantial amount of sophisticated scientific equipment.

The research team has presented several options to NASA. The agency could either renovate an existing BSL-4 laboratory or construct a separate facility. NASA is also considering other options, such as building a high-level containment lab in a modular format at a lower cost.

The team’s investigation indicates that constructing a research site could take between 8 to 12 years, exceeding the timeline for the sample return to Earth. Therefore, team members recommend that NASA develop a plan as soon as possible.

One reason for accelerating the timeline is that failures are almost certain. The laboratories visited by the RAMA team are facing a multitude of regulatory, financial, and construction challenges.

Perseverance rover and Ingenuity helicopter on Mars. (Photo: NASA).

The research team identified that delays would pose “significant risks” to the Mars Sample Return mission. The process of receiving samples will be more complex due to the involvement of paperwork procedures.

NASA wants the project to comply with planetary protection policies, as well as its own additional policies. The sample receiving facility must also be approved under the National Environmental Policy Act.

Furthermore, the spacecraft and infrastructure will have to adhere to Presidential Directive 25 on National Security. This directive pertains to scientific experiments and technologies that could have a significant environmental impact.

Engaging with the public is key to the project’s success. Dr. Rummel believes that transparency will garner public support, ensuring accountability and safety for the project.

NASA’s investment in building a secure facility could lead to unexpected outcomes.

“There will be some very interesting technical challenges. This could yield more benefits for humanity than what the samples from Mars provide,” said Scott Hanton, Editor Lab Manager.