NASA Launches $1 Billion ICESat-2 Spacecraft to Study Ice Melt

By Katherine Mast | September 15, 2018 10:30 am
ICESat-2 satellite spacecraft orbits Earth

NASA’s ICESat-2 spacecraft will measure the height of Earth’s melting ice. (Credit: NASA Goddard Space Flight Center)

Since 2003, NASA has been monitoring the height of Earth’s ice with lasers. This undertaking began with a satellite — the Ice, Cloud, and Land Elevation Satellite (ICESat) — which ran through 2009. Operation IceBridge has used planes to monitor specific vulnerable ice sheets in the years since. Now, the project continues with ICESat-2, which successfully launched September 15 from Vandenberg Air Force Base in California.

Bearing one of the most sophisticated elevation-monitoring lasers ever made, ICESat-2 will measure the height of Earth’s ice, seas, land and trees for the next three-to-seven years, helping to produce a detailed, 3-D map of the planet and detect small, annual changes in elevation. If a glacier loses even 4 millimeters of height, ICESat-2 will let us know.

New Eyes on Earth

Here’s how it will work: ICESat-2’s instrument – the Advanced Topographic Laser Altimeter System (ATLAS) will produce 10,000 pulses of green laser light each second, then split each pulse into three pairs of beams, sending 300 trillion photons to Earth with each pulse. A tiny fraction of those photons — about a dozen from each pulse — will strike a surface and reflect back to ATLAS, which will record the round-trip time for each photon.

“That light should take about 3.3 milliseconds to make the round-trip from the spacecraft to the Earth and back again,” says Tom Neumann, the Deputy Project Scientist for ICESat-2 at NASA’s Goddard Space Flight Center. “ICESat-2 and its instrument are able record those round-trip times to better than a billionth of a second.”

Those flight times, paired with similarly precise information about ICESat-2’s position in space, will give scientists a detailed reading of the elevation and slope of glaciers, icebergs, waterbodies and forests.

Changes in those elevations will reveal things like where ice is melting the fastest, how much is melting, and how that relates to areas with snow accumulation. Scientists also plan to use the data to track forest biomass; the height of a forest canopy can be a proxy for how much carbon its trees contain.

Engineering Flaws

It’s taken nine years – more than a year longer than initially thought – and about $1 billion to design and test all the components, and to resolve issues with the ATLAS laser.

“The ICESat-2 instrument is the cutting edge of laser altimetry,” says Neumann, who has worked as a liaison between the scientific community and the mission’s engineers. “Anytime you’re doing something new like that, the time it takes to develop or integrate or test such new equipment can take longer than you initially thought, and that was definitely the case with ICESat-2.”

But even with extensive testing, things can go wrong; ICESat-1 had engineering flaws that didn’t show up until it was in orbit. Unlike ICESat-2’s ATLAS, which uses a single laser, ICESat-1’s Geoscience Laser Altimeter System (GLAS) instrument had three, each with an expected lifespan of about a year. But just 38 days after it began firing, the first laser failed.
Because all three lasers used the same parts and construction, NASA anticipated the same problem would destroy the other two lasers, so the agency came up with a new plan: instead of firing continuously, the remaining lasers would only operate periodically and at a lower temperature.

ICESat Insights

Despite the mid-game change, ICESat-1 offered scientists new insights.

“What we found in Greenland was that almost all of the thinning was concentrated at those outlet glaciers that feed into the oceans,” Neumann says. “We also found that the middle of Greenland was slightly thickening, which is exactly what the theory would suggest: as the air around Greenland gets warmer and holds more water vapor, it can lead to increased precipitation.”

They also used the spacecraft to study Antarctic glaciers. And we now know that land ice from Greenland and Antarctica is melting rapidly, adding about 375 gigatons of water to the oceans each year.

Data from ICESat-2 will give us an even better picture of the impacts of climate change and will help scientists refine predictions for future changes. “If a model can accurately reproduce the shape of the ice sheet as measured by ICESat-2 and the change in the shape of that ice sheet, it gives us a lot more confidence in those models predictions going forward,” says Neumann.

Editor’s Note: This story has been updated from an earlier version.

CATEGORIZED UNDER: Environment, Space & Physics
  • Uncle Al


    The Soviet of California will launch the first of many data-preloaded $1 trillion satellites, the Feuer Stoßtruppen (thank you, Linda Ronstadt) to double the Carbon Tax on Everything to pay for it. Novel solid fuel boosters will employ pulverized California legislation mixed with angels’ tears.

    • OWilson

      “We’re going to launch our own satellite — our own damn satellite to figure out where the pollution is and how we’re going to end it.” – Jerry Brown

      Everybody knows, except apparently the dear Governor, that La La Land has 6 out of 10 of the worst cities in the nation for air quality.

      Ah, but he means well!

      • 7eggert

        So what are we gonna do about too many people confined in a small space doing too much pollution? Forbid it? That would be too “liberal” (look up the word, BTW). More taxes on pollution? Uncle Al said no.

        I got it: Let’s all keep it that way and form a circle of finger-pointing!

        Under no circumstances we should make local laws in order to improve the environment nor lobby (in your case I presume) Washington to do so. (In my case: Brüssel)

        • OWilson

          Local politicians should make local laws.

          Maybe do something about the growing homeless population?

          See: “Why is liberal California the poverty capital of America?” – L.A. Times.

          See also, “The weeklong climate summit, hosted by California Gov. Jerry Brown, featured appearances by Mr. Gore, Democratic megadonors Michael Bloomberg and Tom Steyer, celebrities Harrison Ford and Alec Baldwin, while also drawing throngs of anti-capitalist protesters”.

          One only hopes they know what they are doing, and we wish them well, in their proposed satellite program. :)

        • Uncle Al

          Democrat Socialism demands that wise philosopher-kings who invariably transform privatized effortless wealth (e.g., Venezuela) into socialized penury and terror (e.g., Venezuela)…mean well.

          A society inundated with rules from religious and secular political classes ignoring productive ends (e.g., Rapa Nui’s moai, Pol Pot in Cambodia, the Soviet of California’s Bullet Train to Nowhere), invariably collapse. Firing squads mean well, too, as did Crusades, Inqusitions, and guillotines.

          • 7eggert

            Sorry for the long posting:

            Some control needs to be more coarse-grained least it turns into too much burden. Otherwise it would hamper production.

            It’s OK to add a cheap safeguard to a machine you sell, but adding a different safeguard for different counties will hamper sales. (Not intending to discuss where which safeguards may or may not be appropriate). It’s OK to tune a car for low NO₂ and sell it in the US, but needing different tuning in each country is bad. Etc. pp..

            Creating these controls need to be bottom-up, but then they need to be applied top-down, for obvious reasons and one I’ll add below. When done correctly, the combination of both will render a firm and stable republic.

            The reason I’d like to add is: What happens if a local authority decides not to abide the law? Then what?

            I may quote Maciavelli (as found already in a quote), as I was made aware of:

            »»»The principle of legality is based on Machiavelli’s observation that “nothing … renders a republic more firm and stable, than to organize it in such a way that the excitement of the illhumors that agitate a state may have a way prescribed by law for venting itself.”

            Machiavelli concludes that “this occurrence shows…how useful and necessary it is for a republic to have laws that afford to the masses the opportunity of giving vent to the hatred they may have conceived against any citizen; for if there exist no legal means for this, they will resort to illegal ones, which beyond doubt produce much worse effects” (Discourses, p.115). People accept legal means, even when the results are not always favorable to them: “For ordinarily when a citizen is oppressed, and even if an injustice is committed against him, it rarely causes any disturbance in the republic” (Discourses, p.115).

            Machiavelli emphasizes a special obligation to obey the law by those institutions that are responsible for it. In 1494, Savonarola determined the fate of Florence and its law. There was hope that citizens can be more secure under his rule. In fact, “a law had been made which permitted an appeal to the people from the decisions which the Council of Eight and the Signoria might render in cases affecting the state…” (Discourses, p.191). “It happened that shortly after its confirmation five citizens were condemned to death by the Signoria on account of crimes against the state; and when these men wished to appeal to the people, they were not allowed to do so, in manifest disregard of the law. This occurrence did more than anything else to diminish the influence of Savonarola; for if the appeal was useful, then the law should have been observed, and if it was not useful, then it should never have been made” (Discourses, p.191).

            I did not read the entire document, but googled for the part I was made aware of; I hope it conveys the meaning.

            I think from this snippet it’s obvious why you correctly observe some societies to fail, and what I reason where we too are in danger – Not to lessen the argument of productive need, I started with that and I regard it as a very important effect of a failed state.

            We need law to have security, security to have production, production to have food, food to have law. But at the same time, we need a law to change the law, and the law itself needs to adhere to itself.

            Let’s compare that to Bishop Ambrosius (transcribed from a movie), thanks to Google translate:
            »»»”The letter means death, but the spirit means life”

            The words of Paul have two meanings
            … (first one left out) …
            But the words of Paul have a second meaning. Remember the
            Mountain rivers. When they encounter an obstacle, they become stronger.
            They tear it with them and fall downhill with even greater force.

            The same thing happens with our yearnings. If by law
            become disabled, they only become stronger and drive us
            Wicked in the arms, and to death.

            In this sense, the law (the letter) can kill.

            But God has also given us his spirit, and the Spirit means
            Life. The mind guides our desires. Through him we love the good.
            He sets us free.«««

            By whatever we chose, there is wisdom not to be ignored.

            I might close with a well-known phrase, and I think that will be a good TL;DR for my too long posting: “Life, liberty and the right to purse happiness”. … “And”, not “or”.

          • OWilson

            Interesting post!

            But in their wisdom, your Founding Fathers, provided a Constitution, which currently allows for the “venting” of populace dissatisfaction by protecting free speech, and mandating elections every two years for Congress, and term limits for your President.

            To some, two years is far too long!

            To paraphrase Churchill, it may not be the perfect system of governance, but it beats the next 10 best.

            And “ensures we shall be governed no better than we deserve”. – GBS

          • 7eggert

            »»»And “ensures we shall be governed no better than we deserve”. – GBS«««

            I disagree. Those who did vote for the now elected government _and_ who were not deceived, they may deserve the “no better” part, but even then, sometimes you have to chose between a chauvinist a*hole and a corrupt snake.

          • OWilson

            To quote Hillary, “Hard Choices” :)

  • Mike Richardson

    The melting of ice sheets, particularly in Antarctica and Greenland, will have an enormous impact on coastal populations in the coming centuries. Despite the political no-sequiturs in the previous comments, this is an important topic for study.

    • CB

      I thought the fossil fuel lobby was able to scrap this satellite!

      Maybe I’m thinking of another one?


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