Europa, one of Jupiter’s moons, has long captivated humans with the possibility that life could exist in the depths of its icy exterior. But could a person actually stand on the surface of Europa and walk around? Let’s take a look at what we know about this intriguing Jovian moon.
What is Europa?
Europa is the sixth-closest moon to Jupiter and the smallest of the four Galilean moons, which are the largest moons orbiting Jupiter. It has a diameter of 3,122 km, making it slightly smaller than Earth’s moon. Europa is primarily made up of silicate rock and has a surface composed mostly of water ice.
But perhaps Europa’s most interesting feature is the global ocean that lies beneath the icy surface. Scientists estimate this subsurface ocean is 62 miles (100 km) deep on average – much deeper than any ocean on Earth. This global ocean is thought to hold more than twice as much water as Earth’s oceans!
The presence of this ocean beneath the icy crust means that Europa has long been considered one of the most likely places to find microbial extraterrestrial life in our solar system. However, the ocean itself is completely covered by the thick crust of ice, which in some areas could be several miles thick.
Europa’s Environment
The surface temperature on Europa averages around -260°F (-160°C). At this frigid temperature, the icy surface of Europa is rock solid. The surface is constantly bombarded by radiation from Jupiter’s magnetosphere. This radiation splits apart water molecules in the surface ice, producing oxygen and hydrogen. The radiation also produces various sulfur compounds that give Europa its stained, multi-colored appearance.
Europa has a very thin atmosphere composed mostly of oxygen. But the surface pressure is one trillionth of that on Earth, making it essentially a vacuum. Europa’s weak gravity (about 13% of Earth’s) means it can’t retain much of an atmosphere anyway.
Could a Human Walk on Europa?
Based on these environmental conditions, it’s clear that the surface of Europa is incredibly inhospitable for human life. A person on the surface of Europa would need to wear a space suit with the following features:
- Pressure sealing and life support system to maintain livable temperature, pressure, and oxygen levels
- Protection from radiation
- Insulation from the extreme cold of the icy surface
- Special boots/shoes to grip the icy terrain
Let’s look at some of the challenges a space explorer would face on the surface of Europa:
Extreme Cold
The frigid temperatures on Europa make it one of the coldest places in the solar system. Any exposed skin would get frostbite almost instantly. Even the thermal insulation built into a space suit might not be enough to protect an astronaut for extended periods on the surface.
According to NASA, the warmest the surface temperature ever gets is around -220°F (-140°C) at the equator. That’s over 200 degrees colder than the coldest temperature ever recorded on Earth (-128.6°F in Antarctica)! Without sufficient protection and insulation, survival would be impossible.
Low Gravity
The gravity on Europa is only about 13% of Earth’s gravity. This makes just moving around quite challenging. On Earth, a 150 pound person weighs 1000 Newtons. On Europa, they would weigh only 130 Newtons. This low gravity makes it difficult to gain traction and maintain your balance as you walk across the uneven icy terrain.
| Planet/Moon | Gravity (compared to Earth) |
|---|---|
| Earth | 1g (9.8 m/s2) |
| Moon | 0.1654g |
| Mars | 0.38g |
| Europa | 0.13g |
As the table shows, Europa has the lowest gravity of any body humans have walked on besides just floating in space. Special training and equipment would be needed to allow astronauts to adapt to this low gravity environment.
Radiation Risks
Jupiter’s magnetosphere bombards the surface of Europa with a high dose of radiation. Over a period of a few days, astronauts would be exposed to about 5,000 times the radiation we experience on Earth in an entire year!
This radiation primarily consists of electrons and ions trapped by Jupiter’s magnetic field. Exposure could increase cancer risk or cause radiation sickness. Lead shielding within the space suit could help protect astronauts, but limited duration missions would be required to minimize exposure.
Icy and Uneven Terrain
Forget about smooth dirt or rock underfoot – on Europa you’d be walking across solid ice, crunchy snow, or slopes of fine ice particles perhaps mixed with salts or other deposits. Sections could be treacherous icy patches or broken terrain full of crevices.
Special boots with rugged treads would be essential for gaining traction on the icy surface. Boots would need heated liners to keep feet from freezing. Steep slopes or cliffs of ice would make exploration dangerous.
Tools like ice axes, tethers, and ropes may need to be used similar to mountain climbers on glaciers or frozen landscapes on Earth. Slow, careful steps would be required for safety across certain terrain.
Conclusion
While it presents some major challenges, with the right equipment, training, and spacecraft support, it would be possible for astronauts to stand and walk across the surface of Europa.
A heated, pressurized spacesuit designed for flexibility and traction would enable mobility across the ice. Limiting duration of exposure could reduce radiation risks. And special tools could aid exploration across uneven or steep areas.
But any Europa surface mission would face significant hazards. Until we can better map the surface and understand local conditions, truly preparing for an astronaut walk on Europa remains difficult. For now, sending robotic probes remains our best way to explore this intriguing icy ocean world.
