SOLARCORE® Insulates Merrell’s ISPO Award-Winning MTL Thermo Rogue 4 Boot

January 4, 2023

Offering unparalleled warmth under compression, SOLARCORE sets a new standard in insulation

Portland, OR /OUTDOOR SPORTSWIRE/ – SOLARCORE®, a NASA-inspired proprietary insulation technology, has helped Merrell earn a 2022 ISPO Award for the outdoor hike and footwear brand’s MTL Thermo Rogue 4 Boot. Recognized for its ability to maintain superior conductive thermal properties under compression, SOLARCORE composite foam is powering the next generation of lightweight, cold-weather, performance footwear.

Traditional foam insulation used in footwear applications rely on the principles of loft–bulk and airspace–to provide warmth to the wearer. Under the weighted compression of footsteps, thermal warmth becomes compromised as the loft in these insulations begin to break down.

Developed using NASA-inspired insulation materials, the same technology used to insulate spacecraft in the -450F environment of space, SOLARCORE represents a leap forward in foam composites. At only 2mm thick, SOLARCORE offers a thermal rating of 30 mW/m-K–nearly half the thermal conductivity of other leading foam insulators–providing exceptional warmth to volume performance. Additionally, under extended periods of compression, SOLARCORE’s thermal properties do not break down—a level of performance current foam alternatives cannot match.

These attributes are what attracted Merrell to SOLARCORE when the footwear brand set out to develop a lightweight running option for winter athletes, the MTL Thermo Rogue 4 Boot. Just two millimeters of SOLARCORE incorporated into the Rogue’s toe box and insole provides runners and hikers with lasting warmth in a lightweight package.

This performance was noted by ISPO’s discerning jury when the panel awarded the MTL Thermo Rogue 4 Boot with best, Light Boots for Winter Hiking. “This is the kind of shoe modern hikers and outdoor enthusiasts are looking for in winter—athletic and durable winter hiking boots,” the Award Jury wrote.

“We’re thrilled that Merrell was able to make the most out of SOLARCORE and recognize its capacity to revolutionize product insulation,” commented Michael Markesbery, the principle behind SOLARCORE technology. “Clearly, the jury at ISPO agreed and rewarded Merrell for designing a great boot and taking the leap toward innovation.”

For all SOLARCORE media inquiries, please reach out to Sam Morse: For all Merrell media inquiries, please contact Jessica Price:


SOLARCORE® is a NASA-inspired proprietary insulation technology, made from Aerogel—the warmest material on Earth. By utilizing the inherent thermal properties found in Aerogel, our patented SOLARCORE® technology (US Patent #10793777B2) is designed to retain its superior thermal performance without the excessive loft usually found in insulation. It’s a zero-bulk approach to insulated warmth with applications spanning the fields of aerospace, research, defense, apparel, and beyond.


Merrell® exists to share the simple power of being outside and is committed to building an inclusive and sustainable environment for future generations to enjoy. As the global leader in outdoor active footwear with the Moab hiking boot and Jungle Moc, Merrell is focused on merging performance, styling, and comfort to empower all people to confidently explore the outdoors. The brand was recently named Footwear News’ 2022 Brand of the Year for promoting a more diverse vision of the outdoors. Visit or follow us on social @Merrell. Merrell® is a division of Wolverine World Wide, Inc. (NYSE: WWW), one of the world’s leading marketers and licensors of branded casual, active lifestyle, work, outdoor sport, athletic, children’s and uniform footwear and apparel.