Why Nothing Can Grow on Mars*

🌈 Abstract

The article discusses the challenges of terraforming Mars and the possibility of growing life on the planet. It explores the key obstacles that life would need to overcome, including radiation, toxins, temperature, atmosphere, and the lack of available water. The article also outlines the efforts of a research nonprofit, Pioneer Labs, to engineer a microbe capable of surviving and thriving in the harsh Martian environment.

🙋 Q&A

[01] Terraforming Mars

1. What are the key obstacles that life would need to overcome to survive on Mars?

• Radiation: High levels of ionizing and ultraviolet radiation that can damage DNA and cellular processes
• Toxins: High concentrations of perchlorate in the Martian soil that are toxic to most life
• Temperature: Extremely low temperatures, with an average surface temperature of -60°C and potential lows of -150°C
• Atmosphere: Thin atmosphere composed of 95% carbon dioxide, with low pressure (1% of Earth's)
• Water: Lack of liquid water, with any available water being in the form of frozen ice or highly saline brines

2. What strategies have some extremophile organisms on Earth evolved to deal with these challenges?

• Radiation resistance: Microbes like Deinococcus radiodurans and Hymenobacter have evolved multiple molecular mechanisms to protect against radiation damage
• Toxin resistance: Organisms like Debaryomyces hansenii can grow in high perchlorate environments by regulating osmotic pressure and stabilizing proteins
• Cold tolerance: Microbes like Planococcus halocryophilus and Psychromonas ingrahamii can grow at temperatures below the freezing point of water
• Anaerobic metabolism: Many microbes can thrive in the low-oxygen Martian atmosphere by using anaerobic metabolic pathways

3. Why is the lack of available water considered the biggest obstacle to life on Mars?

• All known life on Earth requires liquid water for survival, but the water on Mars is either frozen or in the form of highly saline brines that are inaccessible to life
• The Martian soil is extremely dry and acts as a desiccant, quickly absorbing any available water
• The water activity (a measure of water availability) on Mars is below the lower limit of 0.585 that can support known terrestrial life

[02] Pioneer Labs' Approach

1. What is the goal of Pioneer Labs' research?

• To understand the true limits of life by engineering a "polyextreme" microbe that can survive the combined challenges of the Martian environment
• To combine the extreme adaptations found in different organisms on Earth to create a microbe that can potentially thrive on Mars

2. What are some of the strategies Pioneer Labs is considering to enable life on Mars?

• Engineering microbes that can produce insulating materials to trap heat and water, creating a more hospitable microenvironment
• Exploring the potential of engineered lichens that can extract water from the Martian atmosphere

3. What are some of the legal and ethical considerations around terraforming Mars?

• NASA's policies and the Outer Space Treaty prohibit the release of microbes in space to prevent harmful contamination
• Terraforming Mars could potentially drive any native Martian life (if it exists) to extinction, which needs to be carefully considered

4. What are the potential benefits of Pioneer Labs' research beyond terraforming Mars?

• The development of polyextreme life could reduce the costs and requirements for manufacturing vital products like therapeutics, food, and materials on Earth
• The research could help support human civilization in space by enabling the use of local resources on other planets and moons