NASA Goddard Profile picture
Nov 3, 2017 11 tweets 4 min read Twitter logo Read on Twitter
Lasers. In. Space.
NASA’s got ‘em! Next year we launch a satellite with lasers, @NASA_ICESat2, to measure Earth’s changing ice #NASASocial
To measure the height of ice, ICESat-2’s instrument ATLAS will send laser light to Earth, and time how long it takes to get back
The satellite will send 10,000 laser pulses EVERY SECOND to Earth. 1 pulse = 300 trillion photons. That’s trillion with a 'T.'
Laser photons would be swamped by sunlight, so @NASA_ICESAT2 filters out everything but its own bright green shade
To cover more ground (& ice & forests & oceans), the instrument’s laser splits into six beams.
The six laser beams are arranged in three pairs, which allows scientists to estimate the cross-track slope of the surface below.
Hold it steady: the ATLAS instrument aboard ICESat-2 has an automatic motorized mirror that keeps the laser stable and pointed correctly.
The satellite will take 1,387 different paths over Earth each season, creating a dense grid of data especially over the poles.
Since each orbit repeats every 91 days, scientists will be able to track how the ice changes between the seasons. #NASASocial!
With all these data points, ICESat-2 can estimate the annual height change of ice sheets to within 4 mm – the width of a No. 2 pencil.
Engineers take ICESat-2 to the extreme – sometimes going big, sometimes small, but always keeping it precise to measure ice (End thread)

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More from @NASAGoddard

Oct 1, 2018
Happy Birthday #NASA. 60 has never looked better!🎉🎂

From the beginning, Goddard has worked to support our agency’s work of uncovering the universe 🌃.

Here are a few ways Goddard has helped along the way. #NASA60th
It started with Dr. Robert Goddard! In 1926, he successfully tested the first rocket using liquid fuel 🚀🚀. Today he’s known as the “Father of Modern Rocketry.” #NASA60th
To honor his discovery, the Goddard Space Flight Center was named after him. Our campus became #NASA’s first space flight center in 1959. #NASA60th
Read 23 tweets
Nov 24, 2017
THREAD: Need a break from #BlackFriday, digging @NASA’s #BlackHoleFriday? Perfect, enjoy our Black Hole 101! ☄️
First the basics. A black hole is a region in space where the pulling force of gravity is so strong that light is not able to escape. Because of this, black holes are invisible. Only telescopes with special instruments can help find them.
There are three main types of black holes. The black hole's mass and size determine what kind it is.
Read 13 tweets

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