Credit: NASA


One of the major messages from Project Apollo is that lunar dust was a significant challenge for moonwalkers due to its strong adhesive and abrasive nature.

New research into the issue may give lunar dust the boot – that is, a new design called Sole Morphing Astronaut Boots (SMABs).

Cleat of foot

A research paper presented this week at the virtual 52nd Lunar and Planetary Science Conference 2021 notes that the boot design strives for two goals:

Computer Aided Design (CAD) drawing of sole morphing astronaut overboot.
Credit: S. Lanctot, et al.


— The first is to minimize surface area contact with the Moon’s surface by elevating the astronaut on an extended cleat-like design to reduce the amount of dust kicked off the ground.

— The second goal will focus on improving the stability and enhancing the sense of foot feel for the astronauts.

Lead author of The Sole Morphing Astronaut Boots paper is Sara Lanctot, a mechanical and aerospace engineering student at New Mexico Tech in Socorro, New Mexico.

Clingy and cloggy 

The Apollo moonwalking boot had its fair share of issues in the lunar dust, Lanctot and her colleagues explain.

“The dust is clingy and clogged up the treads of the boots. Astronauts commented on how slippery the boots would get, especially on the ladder. Furthermore, the abrasive nature of lunar regolith acting on a standard soled shoe was able to wear through the sole within a single day’s worth of activity on the lunar surface.”

Apollo 17 helmets and dusty spacesuits stuffed inside lunar lander following the last human treks on the Moon in December 1972.
Credit: NASA

The multi-layered Sole Morphing Astronaut Boots (SMAB) incorporate an adaptive design with replaceable studs to allow for maintenance and to reduce the general problem of “gouging” out dust from the lunar surface.

Spring in your step

The sole of the shoe will contain thirteen studs located where the foot holds the most weight: the heel and balls of the feet.

Each stud has what’s called a shock-absorption mechanism (SAM), similar to a shock absorber found in an automobile. This mechanism is intended to make the studs both shock absorbent and surface conforming.

View of stud CAD modeling and components. Credit: S. Lanctot, et al.

By literally putting a spring into your step via SMABs, the result is reducing dust clouds and aiding astronauts with their lunar treks. Secondly, Moon strutting crews wearing SMABs will receive firm and stabilizing footing as they walk over the uneven lunar surface, littered with rocks and small craters, the research team reports.

Haptic sock

The insole of the SMAB are outfitted with four piezoelectric ceramic disks that are placed strategically in the posterior metatarsal, heel (hind foot), great ball and little ball of the foot – these are common pressure points of the human foot.

The right shows the placement of the stubs on
the foot. The left foot indicates the corresponding placements of the piezoelectric ceramic sensors.
Credit: S. Lanctot, et al.

A “haptic sock” consists of about six vibrational motors each housed in a memory foam padding. Haptic relates to or is based on the sense of touch. Aluminum pins, when vibrated by the motors, provide the wearer with simulated tactile sensory information.

Lanctot and her colleagues have put together a test program to evaluate the effectiveness of the SMAB prototype in comparison to previous lunar mission boots both in regards to dust kick-up and overall traction.

“A large part of our proposed verification testing will be the development of the piezoelectric-haptic-system. While the haptic system is already being researched for use in gloves of EVA suits of astronauts aboard the ISS, this concept has not yet been transferred to the boots of the astronauts to improve gait and balance,” Lanctot and associates explain in their LPSC paper 

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