Experiments that demonstrate 3D printing with dust, use engineered tissue to study muscle loss, and analyze growth of slime mold, along with other scientific studies and supplies, are headed to the International Space Station on Northrop Grumman’s 16th commercial resupply services mission (NG CRS-16). Launch of the Cygnus spacecraft is targeted for August 10 from NASA’s Wallops Flight Facility in Virginia.

The experiments carried by this spacecraft add to a long list of studies conducted during more than 20 years of continuous human habitation of the orbiting lab, helping researchers explore farther into space and benefiting humans back on Earth.

Download high-resolution photos and videos of the research mentioned in this article.

Reporters who want to hear more from the researchers behind these studies, sign up now for the NG CRS-16 science media telecon on August 2, 2021.

Here are details on some of the scientific investigations traveling to the space station on this mission:

From dust to dorm

Using resources available on the Moon and Mars to build structures and habitats could reduce how much material future explorers need to bring from Earth, significantly reducing launch mass and cost. The Redwire Regolith Print (RRP) study demonstrates 3D printing on the space station using a material simulating regolith, or loose rock and soil found on the surfaces of planetary bodies such as the Moon. Results could help determine the feasibility of using regolith as the raw material and 3D printing as a technique for on-demand construction of habitats and other structures on future space exploration missions.

The investigation prints samples using the Made in Space Additive Manufacturing Facility and returns them to Earth for analysis and comparison with samples produced in a ground facility prior to launch. This comparison helps validate that the process works at levels of gravity lower than that on Earth. The work also continues research and development to advance additive manufacturing of habitats that NASA began in 2015 with the 3D-Printed Habitat Centennial Challenge.

“Redwire Regolith Print demonstrates a key manufacturing capability for building critical infrastructure on the Moon,” said Andrew Rush, President and COO of Redwire.  “Technology that enables us to use local, available resources to produce what we need off-Earth is critical for NASA’s Artemis missions and sustainable exploration of the Moon, Mars, and beyond.”  

Maintaining muscles

As people age and become more sedentary on Earth, they gradually lose muscle mass, a condition called sarcopenia. Identifying drugs to treat this condition is difficult because it develops over decades. Cardinal Muscle tests whether microgravity can be used as a research tool for understanding and preventing sarcopenia. The study seeks to determine whether an engineered tissue platform in microgravity forms the characteristic muscle tubes found in muscle tissue. Such a platform could provide a way to rapidly assess potential drugs prior to clinical trials.

“Since sarcopenia evolves over a period of decades, it has been very difficult to study potential treatments to combat this syndrome on Earth,” said principal investigator Ngan F. Huang, assistant professor of cardiothoracic surgery at Stanford University. “We believe that bioengineered skeletal muscle will be a useful platform for performing high-throughput drug screening studies in microgravity that could help astronauts during extended space missions as well as the millions of people who suffer from sarcopenia on Earth.” 

Taking the heat out of space travel

The Flow Boiling and Condensation Experiment (FBCE) aims to develop a facility for collecting data about two-phase flow and h
eat transfer in microgravity. Comparisons of data from microgravity and Earth’s gravity are needed to validate numerical simulation tools for designing thermal management systems.

Longer space missions will need to generate more power, producing more heat that must be dissipated. Transitioning to two-phase thermal management systems reduces size and weight of the system and provides more efficient heat removal. Current single-phase heat transfer systems use a liquid such as water or ammonia to remove heat from one location and move it to another while remaining in the same phase (liquid). Two-phase systems use the source of heat to boil the liquid, changing the liquid into a vapor. Because greater heat energy is exchanged through vaporization and condensation, a two-phase system can remove more heat for the same amount of weight than current single-phase systems.

“This is one of the most sophisticated fluid physics experiment to be conducted in long-duration microgravity,” says principal investigator Issam Mudawar, director of the Purdue University Boiling and Two-Phase Flow Laboratory. “It is unique in that it can serve as platform for future use by the fluid physics community at large and not just a single team.”

This research is a joint effort between Mudawar’s lab and NASA’s Glenn Research Center.

Cooler re-entries

KREPE demonstrates an affordable thermal protection system (TPS) to protect spacecraft and their contents during re-entry into Earth’s atmosphere. Making these systems efficient remains one of space exploration’s biggest challenges, but the unique environment of atmospheric entry makes it difficult to accurately replicate conditions in ground simulations. TPS designers rely on numerical models that often lack flight validation. This investigation serves as an inexpensive way to compare these models to actual flight data and validate possible designs. Before flying the technology on the space station, researchers conducted a high-altitude balloon test to validate performance of the electronics and communications.

“The design of an efficient TPS remains one of the most challenging tasks of planetary exploration missions,” says principal investigator Alexandre Martin of the University of Kentucky. “Over the past 50 years, only a handful of near-orbital entry experiments have been performed. These flights were part of elaborate and costly exploration programs, and the TPS tests were at the final stage of design after extensive ground test campaigns using arc-jet and hypersonic tunnel facilities. None were flight proven. There is clearly a need to provide a low-cost way to quickly and reliably evaluate TPS materials and provide near-orbital flight validation data.”

Three capsules outfitted with a variety of sensors and materials ride in the Cygnus resupply spacecraft when it departs the space station, deploy when Cygnus re-enters the atmosphere, and collect and transmit thermal data from their sensors. Better materials and designs for heat shielding also have potential applications on Earth, such as for fires and volcano disasters.

Getting the CO2 out

Four Bed CO2 Scrubber demonstrates a technology to remove carbon dioxide from a spacecraft. It is one of two carbon dioxide removal technology demonstrations for the space station’s Exploration Environmental Control and Life Support Systems (ECLSS). Based on the current system and lessons learned from its nearly 20 years of operation, the Four Bed CO2 Scrubber includes mechanical upgrades and an improved, longer-lasting absorbent that reduces erosion and dust formation. Absorption beds remove water vapor and carbon dioxide from the atmosphere, returning water vapor to the cabin and venting carbon dioxide overboard or diverting it to a system that uses it to produce water. This technology could improve the reliability and performance of carbon dioxide removal systems in future spacecraft, helping to maintain the health of crews and ensure mission success. It has potential applications on Earth in closed environments that require carbon dioxide removal to protect workers and equipment.

“Four Bed CO2 Scrubber is a great example of how valuable the space station has been for learning how to build and operate systems for space exploration,” says co-investigator Michael Salopek of NASA’s Johnson Space Center. “Building robust and reliable systems would be much more challenging without this low-Earth orbit test bed.”

Mold in microgravity

An ESA (European Space Agency) investigation, Blob, allows students aged 10 to 18 to study a naturally-occurring slime mold, Physarum polycephalum, that is capable of basic forms of learning and adaptation. Although it is just one cell and lacks a brain, Blob can move, feed, organize itself, and even transmit knowledge to other slime molds. Students replicate experiments conducted by ESA astronaut Thomas Pesquet to see how the Blob’s behavior is affected by microgravity. Using time lapse video from space, students can compare the speed, shape, and growth of the slime molds in space and on the ground. The National Center for Space Studies (CNES) and the National Center for Scientific Research (CNRS) in France coordinate Blob.

“As part of the twelve French experiments of Pesquet’s mission, Blob is a unique experience that stimulates student curiosity about themes such as the impact of the environment on organisms and the development of living organisms,” says Evelyne Cortiade-Marché, head of the CNES education department. “This educational experiment offers the opportunity to carry out a real scientific experimental process in a playful, collaborative and media-oriented context.”