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For more than 50 years,

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NASA’s mapped the globe

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with all kinds of data.

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But have you ever looked at the poles

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and wondered

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what’s going on up here?

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And down here?

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Sometimes referred to as a

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“pole hole,”

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this is the boundary of the orbit

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of the ICESat-2 satellite,

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meaning it can’t gather data

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from this 440 kilometer

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diameter circle at the poles.

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When these regions are mapped for

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land ice or sea ice,

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these signify the holes

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or gaps in the data collection.

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Well, then,

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why can’t ICESat-2

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just fly over these pole holes

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and fill in those gaps?

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It goes back

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to the design of the mission.

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ICESat-2 was designed to measure

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the heights

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of the polar regions

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and the elevation

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of many other features

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around the globe.

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If the angle of its orbit,

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or inclination,

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was to change to get closer

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to the north and south poles,

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then ICESat-2

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would cover less of the edges

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of the ice sheets,

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where much of the change

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is happening,

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as well

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as less of the mid-latitude region.

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When designing a big global mission,

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you need to consider the tradeoffs

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of measuring one region

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or variable, versus another,

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and this was the balance

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ICESat-2 was designed for.

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In fact, ICESat-2

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measures more of

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the polar regions

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than its predecessor,

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ICESat.

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And we can tweak the direction

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ICESat-2

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is measuring through off pointing.

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Careful planning goes

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into commands

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sent to the spacecraft

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to off point by

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up to ten degrees,

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which then covers

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half of the gap at the pole.

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Like many missions, ICESat-2

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strikes a strategic balance

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between scientific goals

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and engineering capabilities.

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And that

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is the “hole” story.