CRS-21 Mission Highlights: Science, Innovation, and Exploration
- Sharife Gacel
- 9 minutes ago
- 7 min read
Throwback to one of the most incredible launches I have seen. It was one of those moments that just hits you, where you can feel the excitement in your chest. Literally. The Commercial Resupply Services CRS-21 mission launched on December 6, 2020 at 11:17 a.m. ET from Launch Complex 39A at Kennedy Space Center in Florida. The mission was contracted by NASA and flown using the SpaceX Cargo Dragon 2 spacecraft.
What made this mission especially exciting was the collection of scientific experiments headed to the International Space Station. Each one expands what we know about living and working in space, many with meaningful applications for life on Earth.
Science Highlights
Bishop Airlock (Nanoracks Bishop Airlock)
The Bishop Airlock, built by Nanoracks with NASA’s support, is the first commercial airlock added to the International Space Station. It acts like a much larger and more flexible “doorway” for moving equipment, deploying satellites, and supporting experiments. As demand grows for sending bigger projects and more CubeSats to space, Bishop helps relieve the traffic bottleneck caused by the station’s older, smaller Japanese airlock.
Bishop offers five times more capacity than the existing airlock and includes standardized mounting racks, electrical and data connections, exterior attachment points, and even a WiFi antenna. It can also be detached and moved to different locations on the station, allowing researchers to expose experiments to conditions like sunlight or atomic oxygen. This flexibility supports a wide range of scientific and commercial work, from Earth imaging and robotics tests to biomanufacturing and advanced material research.
The airlock is part of NASA’s strategy to grow a sustainable economy in low Earth orbit through public-private partnerships. Under a Space Act Agreement, Nanoracks built the airlock while NASA provides power, communications, and astronaut support. NASA has already pre-purchased uses for tasks such as satellite deployment, experimental testing, and even new approaches to trash disposal. The airlock may also streamline spacewalks by serving as an external toolbox for specialized equipment.
Bishop also expands opportunities for private companies, universities, and international partners. Its increased capacity supports the rapidly growing CubeSat industry and enables more experiments than ever before. Nanoracks’ customer list includes commercial space companies, consumer brands, research institutions, and educational programs. This partnership structure helps NASA focus on deep space exploration while enabling industry to grow new markets in low Earth orbit.
Overall, the Bishop Airlock represents a major step in enabling more science, more commercial activity, and more innovation on the space station, while demonstrating how NASA’s public-private partnerships continue to build the future of space research and technology.
BioAsteroid
As humanity plans for long term living and working on places like Mars, scientists are exploring how to gather necessary materials directly from space. The ESA BioAsteroid experiment, launched on the CRS-21 mission, tests whether microbes can extract useful elements from asteroid material in microgravity. Using small bioreactors filled with pieces of a 4.5-billion-year-old chondrite asteroid, the study examines how bacteria and fungi attach to and break down rock in space.
Biomining, already used on Earth as an environmentally friendly method of extracting elements, relies on microbes that naturally dissolve rock and release nutrients or minerals. Previous research (BioRock) showed that microbes can biomine basalt even in microgravity or Martian gravity. BioAsteroid builds on this by focusing specifically on asteroid material and by testing combinations of bacteria and fungi, including aggressive rock-dissolving fungi known for producing acids.
Over a 19-day period on the ISS, billions of microbes will interact with the asteroid sample to see whether they can accelerate its breakdown and release valuable elements. The long term goal is to understand whether biomining could support future space settlements by providing essential materials for construction, technology, and life support systems. In short, the experiment explores whether microbial “miners” could one day help humans build and thrive beyond Earth.
Hemocue
As humans prepare for long distance missions to places like the Moon and Mars, astronauts will need the ability to diagnose medical problems far from Earth. One essential tool is measuring white blood cell counts, which help determine infections and guide treatment. Currently, astronauts can only collect blood samples for analysis after returning to Earth.
NASA’s Human Research Program tested a small commercial device called HemoCue, which can perform a white blood cell count from a single fingerstick in just minutes. The demonstration aboard the International Space Station showed, for the first time, that accurate hematology analysis is possible in microgravity. This is a major milestone because fluids behave differently in space, making traditional lab techniques difficult.
The test, supported by astronauts Mike Hopkins and Kate Rubins, proved that point-of-care medical diagnostics could eventually become standard for deep space missions. If refined and adopted, HemoCue would allow astronauts and flight surgeons to diagnose infections, monitor treatment responses, and better manage health during long-duration missions where returning to Earth is not an option.
Brain Organoids
Scientists are sending 3D models of the human brain, called neural organoids, to the International Space Station to study how they grow and behave in microgravity. These organoids, made from patient-derived stem cells, allow researchers to model brain development and neurodegenerative diseases such as Alzheimer’s and Parkinson’s. Microgravity accelerates neural growth and changes how cells develop, interact, and mature, offering insights that are difficult or impossible to obtain on Earth.
A team from the National Stem Cell Foundation, the Scripps Research Institute, and the New York Stem Cell Foundation conducted the first ISS study using disease-associated neural organoids. Their recent findings show that neural development progresses faster in space, opening new possibilities for studying the mechanisms behind neurodegeneration and for testing therapies more rapidly.
By observing how brain cells respond to the unique space environment, scientists hope to uncover clues that could lead to breakthroughs in treating neurological disorders. This research represents a major step forward in understanding brain biology and demonstrates how space-based science can accelerate medical discovery and improve health on Earth.
Cardinal Heart
Scientists are using tissue chips, small devices containing human cells that mimic real organs, to study disease and test drugs more safely and efficiently. These chips behave even more like real human tissues in microgravity, making the International Space Station an ideal research platform.
The Cardinal Heart experiment sent engineered heart tissues (EHTs) to the station to investigate how microgravity affects heart cells. Results showed clear changes in the tissues, and researchers plan to test drugs next to see whether those changes can be prevented, which could improve treatments for cardiac atrophy on Earth.
Tissue chips offer a powerful alternative to animal testing, which often fails to predict human responses. Because chips are small, robust, and three dimensional, they can remain in space for long periods, allowing scientists to observe long term effects and chronic conditions.
Other studies on the station have used tissue chips to explore muscle loss, blood vessel function, cartilage injury, and immune system aging. These experiments have revealed accelerated aging-like processes in space, helping researchers model diseases in days or weeks instead of months or years.
Overall, tissue chip research in space is transforming biomedical science. By showing how human cells behave, weaken, adapt, or recover in microgravity, these studies are helping scientists develop better drug candidates, understand human aging, and create new therapies that could one day improve health for millions of people.
SUBSA-BRAINS
BRazing of Aluminum Alloys IN Space (SUBSA-BRAINS) studies how liquid brazing alloys behave when they melt and solidify in microgravity. The experiment focuses on key processes such as capillary flow, reactions at the bonding interface, and bubble formation, all of which influence how strong and reliable a brazed joint becomes. Brazing involves bonding similar or dissimilar materials, like aluminum to aluminum or aluminum to ceramics, at temperatures above 450°C using a molten interlayer metal.
Understanding how these materials behave in weightlessness is important because brazing could be used to construct or repair spacecraft, habitats, and other systems during future missions. It may also provide a way to fix damage caused by micrometeoroids or space debris. On Earth, insights from SUBSA-BRAINS can help improve advanced brazing and joining technologies used in construction and repair industries.
Three-Dimensional Microbial Monitoring (3DMM)
Three-dimensional Microbial Monitoring of the ISS Environment (3DMM) creates a detailed map of the microbes and chemical molecules found on surfaces throughout the International Space Station. Using one thousand dual-headed swabs collected from 1,000 different sites, researchers analyze both DNA (for identifying microbial species) and metabolites (for understanding chemical activity).
The experiment uses advanced sequencing, mass spectrometry, and bioinformatics tools to determine how spaceflight conditions affect microbial growth, gene expression, and chemical production. The goals include building a taxonomic inventory of ISS microbes, generating metagenomic profiles to understand their genetic potential, and producing metabolomic profiles that reveal the molecular signatures left by microbes, humans, and environmental factors.
Researchers integrate these multiple data types to understand how microbes adapt to microgravity and how they interact with the space station environment. The project also trains scientists in interpreting microbiome and metabolome data. Overall, 3DMM helps improve monitoring of spacecraft environments and advances knowledge needed for long duration human space missions.
Watching this launch was a reminder of how much science, imagination, and human curiosity can travel on a single rocket. What an unforgettable moment.
References
CRS-21 General Mission Information:
NASA CRS-21 Blog Archive:https://www.nasa.gov/blogs/spacexcrs21/
NASA CRS-21 Mission Overview (PDF):https://www.nasa.gov/wp-content/uploads/2020/12/spacex_crs-21_mision_overview_high_res_0.pdf
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