MSAC mission to ISS: Aerogel formation in microgravity

By sending controlled aerogel synthesis experiments to the International Space Station, researchers from SRI aim to isolate the role of gravity‑driven motion in the formation of these highly porous structures and unlock insights that could improve sustainable technologies back on Earth.

Aerogels for a Changing Climate

Carbon dioxide (CO₂) remains one of the primary drivers of climate change, and even with rapid emission reductions, many models indicate that direct air capture (DAC) will be needed to meet global targets. For years, mission collaborator SRI has been developing polymer aerogels, extremely lightweight, sponge‑like materials that selectively absorb CO₂. Their performance depends critically on their internal pore network: pore size, distribution, and connectivity all determine how effectively the material can capture and release gas. Read more about it here.

Although their chemistry is well understood, controlling pore formation on Earth is challenging. As aerogels form in liquid solutions, small differences in temperature, composition, and density lead to convection and sedimentation, subtle flows that can disrupt how pores connect and grow. Even modest fluid motion during synthesis can imprint variations into the final material.

Why Microgravity Matters

The ISS environment offers a rare opportunity to examine aerogel formation without gravity‑induced mixing. In microgravity, buoyancy‑driven convection and settling are strongly reduced, allowing polymer clusters (microgels) to grow and interconnect more gradually and evenly. Suppressing these flows is expected to produce a more uniform pore network, potentially resulting in:

• greater accessibility of CO₂‑binding sites
• faster diffusion of gas through the material
• improved capture capacity and efficiency

The MSAC experiment uses microgravity as a controlled laboratory. By comparing aerogels formed in orbit with identical samples produced on the ground, the team can directly determine how gravity influences and shapes the material’s structure and how to better mimic microgravity‑like conditions in terrestrial reactors.

Potential Impact on Carbon Capture

A more uniform aerogel network is expected to enhance all major performance metrics relevant to DAC technologies, from adsorption capacity and kinetics to material durability and cost. Better structural control may reduce the mass of sorbent needed for large‑scale capture systems and lower associated plastic waste. Analyses suggest that improvements in pore uniformity could lead to significant cost reductions for DAC processes, supporting more scalable and sustainable deployment.

From Space to Earth: Translating Insights

Once the aerogel samples return from orbit, SRI scientists will perform detailed structural and performance characterization. These results will guide the design of improved synthesis strategies on Earth, such as tuning heating profiles, reactor geometries, or formulation parameters to better regulate fluid motion during gelation. While gravity cannot be removed from industrial manufacturing, the microgravity benchmarks will show what is achievable when convection is minimized, providing a clear target for engineering efforts.

Broader Scientific Relevance

Beyond carbon capture, understanding the interplay between reaction kinetics and fluid transport is important across many fields of polymer science and materials engineering. Microgravity offers a unique platform to study gelation processes over timescales of hours to days, something short‑duration microgravity environments cannot provide.

By exploiting the ISS as a research laboratory, the MSAC mission aims to uncover fundamental principles that can enable more efficient, affordable, and sustainable materials back on Earth, a step toward more effective carbon‑capture systems, and cleaner industrial processes.

MSAC is manifested for launch to the ISS on NG-24 (NET 8 April) and will conduct its mission accommodated in the ICE Cubes Facility in Columbus, with return planned on SpX-34 in late June.