The International Space Station
Credit: NASA
Wrapped snugly in a custom container, seven carefully chosen materials left Earth on Aug. 24, 2025, traveling at 17,500 mph. Nestled at the top of a Falcon 9 rocket, house dust, freeze-dried human liver and cholesterol joined four other scientific specimens to travel to the International Space Station (ISS). Called reference materials, these thoroughly studied samples serve important roles on Earth — and now beyond. These reference materials will play a critical role in understanding the effects of outer space on everyday objects as space becomes a place where people live, conduct research and even start new businesses. For example, drug development is already happening in low Earth orbit. As this kind of research grows, so will the need for reference materials.
Getting these reference materials into orbit was a collaborative effort among NIST, the National Oceanic and Atmospheric Administration (NOAA) Office of Space Commerce and the biotech company Rhodium Scientific. The goal is to advance U.S. leadership in the space sector by supporting the development of innovative commercial and scientific capabilities in outer space. This effort also supports the goals of two recent executive orders on U.S. activities in space.
What Is a Reference Material?
From spinach and cement to human fecal matter, over a thousand different reference materials sit in a Maryland warehouse until they are shipped to companies and scientists around the globe.
Many types of research and industry depend on the reference materials created and maintained by the National Institute of Standards and Technology (NIST). Labs can compare measurements of their specimens to these well-measured materials and calibrate their measurement devices to ensure that they are giving accurate readings. NIST’s cholesterol reference material, for example, helps medical labs make sure their instruments for measuring cholesterol are working correctly. It’s a vital quality control measure for monitoring people’s health. Reference materials also help scientists communicate across time and space. If a researcher uses a reference material in a study, anyone can recreate that experiment by using that same reference, even if they’re on a different continent decades later.
Six of the seven materials sent on this trip are not just reference materials, but standard reference materials (SRMs), meaning that they meet NIST’s highest standard for measurement. They are , , , , and . The seventh sample, the human liver, is a reference material, which is NIST’s next-highest standard. (See this page to learn the differences.)
Why Did We Send Them to Space?
Space affects people and things in unexpected ways. Its low-gravity environment causes astronauts to lose bone density and can weaken their cardiovascular systems. Above Earth’s protective magnetic field, radiation from the Sun and other stars is more potent than on Earth.
It’s not always obvious how outer space will affect things that have never been in orbit. In one stark example, a 2023 elementary school project showed that epinephrine, a drug used to treat life-threatening allergic reactions, chemically transforms into poisonous benzoic acid when exposed to cosmic radiation. It would be very bad if an astronaut or space tourist was accidentally injected with benzoic acid while trying to recover from anaphylaxis.
The chemical changes caused by space are not all negative. For example, it’s easier to grow protein crystals in microgravity. Taking advantage of this, scientists on the ISS studied the cancer drug Keytruda, which is made of protein crystals. The crystals of the drug formed much more evenly in microgravity than on Earth. This research led to a more convenient version of the drug that could be injected rather than slowly dripped through an IV bag.
“There are opportunities for whole categories of research and manufacturing in space, and standards will play an important role out there, just like on Earth,” said NIST research chemist Dianne Poster, who is serving as senior adviser to NOAA’s Office of Space Commerce.
Scientists still don’t know much about how the space environment affects molecules important to human health. Space may make tiny but important changes to organic molecules in liver and other tissue.
“If people are going to be in space for any extended time, they’re going to have to do medical testing, and we’ll need to know how stable their cholesterol and urine molecules are in space and on Earth,” explained NIST scientist Kate Rimmer. “These SRMs are an early step in getting that better understanding.”
Credit:
NIST
The seven chosen reference materials were the first to go into space because they are important for human health and relatively easy to launch into orbit. These SRMs come in a dry powder that can stay at room temperature, making them easier to package for space than, say, a blood plasma reference material, which needs to be at the very cold temperature of minus 80 degrees Celsius.
They are also some of NIST’s best-measured materials. Five of them are “primary chemistry standards,” extremely pure and stable chemicals that are easy to work with. “Primary standards are measured as completely as possible with current technology,” said Rimmer, “and because of this, they are the starting point for many other chemical measurements.”
The house dust SRM is not a primary standard, but it was chosen because it’s one of NIST’s best characterized SRMs and it contains lots of different chemicals that can affect human health. The dust was collected from vacuum cleaner bags across six different U.S. states. “Dust contains chemicals that people are exposed to every day, like outdoor pollutants from vehicle emissions and pesticides — all those things make their way into house dust,” explained Poster, who helped develop the SRM in 2007. “It’s a very good reservoir of these contaminants.”
Studying house dust provides insight into indoor air quality, how chemicals move indoors, and potential health risks. There is dust on spacecraft, just as there is in any place people live and work. As space becomes more populated and commercial space stations emerge, studying dust could be a useful tool for understanding and managing what’s in the air within a closed environment.
“Standardizing how we measure biological and chemical changes in space is essential for creating a resilient, self-sustaining ecosystem where research and commerce can thrive,” said Gabriel Swiney, director of NOAA’s Office of Space Commerce’s Policy, Advocacy and International Division. “This mission is a critical step toward a more dynamic and scalable space economy.”
What Will Happen at the End of the Project?
NIST packaged the reference materials in special containers designed for space travel by Rhodium. While in space, the materials will stay in their packaging until it’s time to come back home. After the mission is over, some of the samples will be sent to Rhodium’s Space BioBank, where they will be held for future research. “Sending a sample to space for research can take years and cost millions of dollars,” explained Rhodium CEO Olivia Holzhaus. “The key idea behind the BioBank is to have lots of different samples that have already been to space ready for testing and instantly available, making space research faster and more efficient. When they return, these space-traveled SRMs will be available to researchers and companies around the world.”
Other samples will go back to NIST, where scientists will use advanced techniques such as nuclear magnetic resonance spectroscopy to measure whether the samples went through any chemical changes during their time on the ISS. The scientists aren’t sure what changes they might see once the SRMs come back to them. Even if nothing changes, that will be valuable information for future space research.
“There aren’t really any physical artifact reference materials for space right now,” said Rimmer. “We’re hoping to help develop the first.”
