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Electromagnetic interference.

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It makes phoning home
a little harder.

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At NASA, we rely on space
communications to hear 
from our spacecraft.

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It's how they send their science
and mission data back to Earth.

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Most missions today use radio
waves to transmit this data.

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Electromagnetic interference

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is a disturbance on 
the communications
link coming to or 
from a satellite.

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This interference, also known
as noise, can result in partial

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or complete data loss.

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Usually this interference is 
caused by a human-made object

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like a car alternator or something
natural, like a solar storm.

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They can come from 
many different things,
which is why NASA communications

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engineers monitor the signals
going to and from a spacecraft.

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They watch to ensure
the signal power --
which contains the 
data comprised

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of digital ones and zeros --
 is higher than the level of 
noise impacting the signal.

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This signal power to noise

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ratio tells the network how 
much usable data they're 
getting back from a mission.

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At the end of the day, our
communications
engineers work to ensure

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NASA's missions can transmit data
without the fear of interference.