Space Biology and Astrobiology: What’s the difference?

From chemistry to physics, NASA researchers from various disciplines conduct groundbreaking work studying life every day.

Two of these disciplines are Astrobiology and Space Biology. While they may sound similar, they are quite different in what they do. What they do have in common is their ability to help us understand how life functions on Earth and in the Universe. 


Astrobiology is the study of the origin, evolution, and distribution of life in the Universe1. The hunt for extraterrestrial life might sound like something out of the science-fiction genre, but scientific logic guides this search.

For NASA scientists, the search to understand life in the Universe starts on Earth. Understanding how life evolved on Earth and what steps made it possible are key to understanding what life might exist outside of it.

To guide us in our search for life beyond Earth, scientists are studying how life on Earth exists in extreme environments like the scorching hot desert or the freezing Arctic tundra. In our solar system, environments like these can be found on Mars or the icy moons2 around Saturn and Jupiter. Future Astrobiology missions will study if these environments in space harbor life.

At the center of this image is a scientist wearing a white clean suit and mask, as well as gloves and goggles. There is a small hole and sterile tools in front of the scientist, who kneels in the soil of the Atacama desert. A desert landscape similar to that of Mars surrounds the scientist, with a vast stretch of dry, rocky soil leading up to shadowed mountains. Above the mountains and set amid a blue sky, the Sun peeks out at the top right of the image, causing a lens flare that stretches across the image.
The Atacama desert is one of the driest places on Earth, making it a good Mars analogy. A scientist searching for signs of life (“biomarkers”) in the soil must use a clean suit, gloves, a mask, goggles, and sterile tools to make sure no contamination ends up in the sample.
Image credit: Alfonso Davila/SETI Institute

In space, tools like robotic science rovers can help scientists search for some of the biosignatures — or signs of life. During the Mars 2020 mission, the rover Perseverance collected data that could be used to look for signs of ancient microbial life3. The rover also collected a suite of samples that a future Mars Sample Return mission will be able to bring back to Earth for study, with all the sophistication and thoroughness of Earth-based instrumentation.

This image shows NASA’s Perseverance rover amid the orange-brown Martian landscape, a desert terrain with small rocks on the surface and hills in the distance, all set against a hazy light brown sky.
This annotated image from NASA’s Perseverance shows the location of the first sample depot — where the Mars rover will deposit a group of sample tubes for possible future return to Earth — in an area of Jezero Crater called Three Forks. The image was taken Aug. 29, 2022.

Understanding both how life emerged and evolved on Earth and what the limits are to life as we know it guides NASA in its mission to search for life elsewhere in the Universe. Astrobiology strives to answer the question: “Are we alone?”  

For more information, follow NASA’s Astrobiology Program on Twitter at @NASAAstrobio.

Space Biology

Space Biology is the study of howthespaceflight environment — such as ionizing radiation, microgravity, isolation, and altered atmosphere — affects life. Studying how living things respond at a fundamental level to these extreme conditions can inform what’s needed to ensure crew health on deep space missions and contribute to biomedical and agricultural advancements on Earth.

The main objective of NASA’s Space Biology research is to better understand how spaceflight affects living systems in spacecraft, such as the International Space Station, as well as in deep space, on planetary surfaces, or in ground-based experiments that mimic aspects of spaceflight.

The experiments NASA conducts on these platforms examine how plants, microbes, and model organisms (such as fruit flies, worms, and rodents) adjust or adapt to living in space. Researchers examine metabolism, growth, stress responses, physiology, and developmental processes.

They study how organisms repair cellular damage and protect themselves from infection and disease in microgravity conditions while also exposed to space radiation. And they do it across the spectrum of biological organization, from molecules to cells, tissues, organs and systems to whole organisms, communities, and ecosystems. 

Another focus of Space Biology is plant biology. Since space is limited aboard spacecraft, astronauts will need access to sustainable, nutritious sources of food for long-term stays in space.

Limited water supplies, microgravity, and different atmospheric and light conditions can affect plant health. Understanding how plants grow in the harsh conditions of space can help scientists determine which ones are most suitable for becoming “space crops.” Research in this field has already contributed to agricultural advancements on Earth, including hydroponic, aeroponic, and vertical farming.

Illuminated by the glow of the Vegetable Production System (“Veggie”) chamber’s magenta LED lights, NASA astronaut Michael Hopkins smells Extra Dwarf Pak Choi, green leafy plants growing inside Veggie aboard the International Space Station.
NASA astronaut Michael Hopkins smells Extra Dwarf Pak Choi plants growing aboard the International Space Station. The plants were grown for one of many Veggie studies, which are exploring space agriculture to sustain astronauts on future missions to the Moon and Mars.

To learn more about how NASA’s Biological and Physical Sciences Division pioneers scientific discovery, follow us on Twitter at @NASASpaceSci.


Astrobiology focuses on the origins, evolution, and the limits to life on Earth to understand where and how to search for life in space. Space Biology studies how Earthly life responds to space environmental conditions to further our understanding of how life operates in built environments for space exploration.

NASA’s research in both fields has contributed to scientific knowledge, biomedical and technological innovations, and agricultural advancements that benefit both space exploration and terrestrial life.