Beneath the Solid Ice

Using its eight mechanical legs, the spider lander nimbly traversed the rugged terrain along the way and arrived safely beside the unexpectedly formed thermal geyser.

Because the thermal geyser continued erupting, the surrounding ice layer had become even more unstable.

However, there were advantages as well as disadvantages. During its eruptions, the thermal geyser brought large amounts of groundwater to the surface, where the low temperatures froze it near the vent.

As a result, an ice chimney resembling a volcanic crater had formed around the vent.

The ice chimney of this small thermal geyser had already grown roughly 71 meters upward from the valley floor and was still continuing to grow.

Like a volcanic crater, the ice chimney was surrounded by a ring of gentle slopes. The spider lander switched its mechanical legs to climbing mode, driving sharp alloy spikes into the icy surface as it climbed upward.

Yet the constant eruptions brought heavy snowfall to the area, even mixed with hail.

As it advanced, hailstones continuously struck the lander's body. Amid a constant patter, it struggled onward and upward.

Though it was called a small thermal geyser, the groundwater and water vapor it erupted could actually shoot as high as 140 kilometers into outer space.

This was mainly because Europa's gravity was relatively weak and its atmosphere was not especially dense. Combined with the immense pressure of the thermal geyser, this allowed the eruption to reach an altitude of 140 kilometers.

At last, it reached the chimney's opening. The spider lander anchored itself firmly to the ice with its mechanical legs and could sense the ceaseless thermal geyser below.

The spider lander extended its sampling arm and collected more than a dozen samples of water vapor and groundwater, all of which had been ejected by the thermal geyser.

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