■ On Earth, Air Helps Us
On Earth, we usually release heat without even thinking about it.
For example, through
● Air
● Wind
● Water
● Convection
In other words, on Earth, air carries heat away for us.
■ There Is No Air in Space
Outer space, however, is nearly a vacuum.
In other words, there is no air.
So what happens?
In fact, heat becomes harder to release.
■ Convection Cooling Does Not Work in a Vacuum
On Earth, heated air rises and releases heat to the surroundings.
This is called convection.
In space, however, because there is no air, convection itself does not occur.
In other words, the idea of cooling with fans does not work as it is.
This is a very big difference.
■ In Space, Radiation Takes the Lead
So how is heat released in space?
What is mainly used is radiation.
In other words, it is a method of releasing heat into space as infrared radiation.
However, radiation is not as efficient as convection on Earth.
In other words, in space, the ability to dump heat itself is limited.
■ Space Also Means Fighting Extreme Temperature Differences
Furthermore, in space,
● Places exposed to the sun → extremely high temperatures
● Shade → extremely low temperatures
In other words, extreme temperature differences occur.
This is extremely tough.
In space, thermal design = survival design
On Earth, many devices keep working even if they get a bit hot.
In space, however, if
● Electronic equipment
● Batteries
● Sensors
● Communication equipment
stop due to temperature abnormalities, it may mean the end of the mission.
In other words, in space, thermal design itself becomes a condition for survival.
■ A Lunar Base Could Become a Thermal Hell
Plans for lunar bases are also advancing.
On the Moon, however, conditions are thermally extremely harsh:
● Almost no atmosphere
● Vacuum
● Intense sunlight
● Extreme temperature differences
In other words, in future space development, how to control heat will be extremely important.
■ Space Robots Also Face Heat Problems
In space robots and probes, too,
● Motors
● AI computation
● Batteries
● Sensors
generate heat.
In space, however, they cannot be cooled by air.
In other words, space robots will end up moving while holding heat.
This is quite tough.
■ Onboard AI Increases Heat Even Further
From now on, AI will also increasingly be installed in space equipment.
For example,
● Autonomous navigation
● Obstacle avoidance
● Communication optimization
● Autonomous decision-making
● Exploration analysis
In other words, in the future, AI computation in space may become common.
At the same time, however, this also means generating heat in space.
■ The Researcher's Perspective: Thermal Design for Space Is a Completely Different World
Current research includes
● Radiative cooling
● High-emissivity surfaces
● Ultra-lightweight heat spreading materials
● Vacuum-compatible materials
● Phase change materials
● Thermal control coatings
In other words, space requires thermal design different from that on Earth.
■ The Shop-Floor Perspective: Things Do Not Go as Theory Predicts
On the actual shop floor, there are extremely harsh conditions, such as
● Vacuum
● Radiation degradation
● Differences in thermal expansion
● Fine deformation
● Long-term durability
● Vibration
● Launch shock
In other words, “works in theory” and “works long-term in space” are completely different.
■ In Space, Lightness Is Also Important
In space, the cost of weight is extremely high.
In other words, wanting to cool and wanting to make it light are required at the same time.
This is extremely difficult.
■ The Space Era Is an Era of Heat × Light Weight × Reliability
The future space industry will require, at the same time,
● Light weight
● High durability
● High reliability
● High heat dissipation
● Vacuum compatibility
In other words, in space, it becomes a complex problem of heat × light weight × long-term reliability.
■ What Matters from OTIS's Perspective
From OTIS’s perspective, what matters in the space era includes
● Thin-film processing
● Microfabrication
● High-precision lamination
● Weight reduction
● Contact between dissimilar materials
● Processing of thermal management materials
● High-precision stacking
● Volume production stability
In particular, making things thin, light, and highly functional is important.
■ What OTIS Can Do
At OTIS, through
● Microfabrication
● High-precision die-cutting
● Thin-film processing
● High-precision lamination
● Processing of thermal management materials
● Processing of lightweight functional components
● Stacking of irregular shapes
we may be able to contribute to making functional components for space work in volume production.
■ Outside OTIS's Expertise
On the other hand, OTIS is not a company that specializes in
● Spacecraft design
● Rocket development
● Space AI development
● Satellite control
● Space thermal analysis
However, in the area of making functional components for space work in volume production processes, we may be able to play an important role.
■ Summary
In the space era, humanity is heading into a world where it cannot cool
The space industry will expand even further from now on.
In space, however, the very act of trying to release heat is difficult.
In other words, future space competition may be decided not only by where we can go,
but also by how well heat can be controlled.
And behind the scenes, technologies that support the final 0.1mm of heat will become increasingly important.
Column Supervisor: Koji Kakumoto (President, OTIS Co., Ltd.)
After studying abroad and working in planning and development at a trading company, he joined OTIS Co., Ltd. in 2011. While primarily working in the Corporate Planning Department, he has also served concurrently in manufacturing and technical divisions, and since 2018 has served as President, working to drive business growth and strengthen the organization.
This article is a general technical explanation intended for educational purposes and does not refer to any specific company, product, or technology.
