New Study Finds Sea Level Rise Accelerating

NASA - IceSat-2 Mission patch / NASA & DLR - GRACE Mission patch.

Feb. 13, 2018

Global sea level rise has been accelerating in recent decades, rather than increasing steadily, according to a new study based on 25 years of NASA and European satellite data.

Sea Level Rise Accelerates Over Time

Video above: Global sea level rise is accelerating incrementally over time rather than increasing at a steady rate, as previously thought, according to a new study based on 25 years of NASA and European satellite data. Video Credits: NASA's Goddard Space Flight Center/Kathryn Mersmann.

This acceleration, driven mainly by increased melting in Greenland and Antarctica, has the potential to double the total sea level rise projected by 2100 when compared to projections that assume a constant rate of sea level rise, according to lead author Steve Nerem. Nerem is a professor of Aerospace Engineering Sciences at the University of Colorado Boulder, a fellow at Colorado's Cooperative Institute for Research in Environmental Sciences (CIRES), and a member of NASA's Sea Level Change team.

If the rate of ocean rise continues to change at this pace, sea level will rise 26 inches (65 centimeters) by 2100 -- enough to cause significant problems for coastal cities, according to the new assessment by Nerem and colleagues from NASA's Goddard Space Flight Center in Greenbelt, Maryland; CU Boulder; the University of South Florida in Tampa; and Old Dominion University in Norfolk, Virginia. The team, driven to understand and better predict Earth’s response to a warming world, published their work Feb. 12 in the journal Proceedings of the National Academy of Sciences.

"This is almost certainly a conservative estimate," Nerem said. "Our extrapolation assumes that sea level continues to change in the future as it has over the last 25 years. Given the large changes we are seeing in the ice sheets today, that's not likely."

Rising concentrations of greenhouse gases in Earth’s atmosphere increase the temperature of air and water, which causes sea level to rise in two ways. First, warmer water expands, and this "thermal expansion" of the ocean has contributed about half of the 2.8 inches (7 centimeters) of global mean sea level rise we've seen over the last 25 years, Nerem said. Second, melting land ice flows into the ocean, also increasing sea level across the globe.

 Ice, Cloud, and land Elevation Satellite-2 (ICESat-2). Image Credit: NASA

These increases were measured using satellite altimeter measurements since 1992, including the Topex/Poseidon, Jason-1, Jason-2 and Jason-3 satellite missions, which have been jointly managed by multiple agencies, including NASA, Centre national d’etudes spatiales (CNES), European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), and the National Oceanic and Atmospheric Administration (NOAA). NASA’s Jet Propulsion Laboratory in Pasadena, California, manages the U.S. portion of these missions for NASA’s Science Mission Directorate. The rate of sea level rise in the satellite era has risen from about 0.1 inch (2.5 millimeters) per year in the 1990s to about 0.13 inches (3.4 millimeters) per year today.

"The Topex/Poseidon/Jason altimetry missions have been essentially providing the equivalent of a global network of nearly half a million accurate tide gauges, providing sea surface height information every 10 days for over 25 years," said Brian Beckley, of NASA Goddard, second author on the new paper and lead of a team that processes altimetry observations into a global sea level data record. "As this climate data record approaches three decades, the fingerprints of Greenland and Antarctic land-based ice loss are now being revealed in the global and regional mean sea level estimates."

Even with a 25-year data record, detecting acceleration is challenging. Episodes like volcanic eruptions can create variability: the eruption of Mount Pinatubo in 1991 decreased global mean sea level just before the Topex/Poseidon satellite launch, for example. In addition, global sea level can fluctuate due to climate patterns such as El Niños and La Niñas (the opposing phases of the El Niño-Southern Oscillation), which influence ocean temperature and global precipitation patterns.

Nerem and his team used climate models to account for the volcanic effects and other datasets to determine the El Niño/La Niña effects, ultimately uncovering the underlying rate and acceleration of sea level rise over the last quarter century.

The team also used tide gauge data to assess potential errors in the altimeter estimate.

 Gravity Recovery and Climate Experiment & Follow-On (GRACE-FO). Image Credit: NASA

“The tide gauge measurements are essential for determining the uncertainty in the global mean sea level acceleration estimate,” said co-author Gary Mitchum, University of South Florida College of Marine Science. “They provide the only assessments of the satellite instruments from the ground.” Others have used tide gauge data to measure sea level acceleration, but scientists have struggled to pull out other important details from tide-gauge data, such as changes in the last couple of decades due to more active ice sheet melt.

In addition to NASA's involvement in missions that make direct sea level observations from space, the agency's Earth science work includes a wide-ranging portfolio of missions, field campaigns and research that contributes to improved understanding of how global sea level is changing. Airborne campaigns such as Operation IceBridge and Oceans Melting Greenland gather measurements of ice sheets and glaciers, while computer modeling research improves our understanding of how Antarctica and Greenland will respond in a warming climate.

In 2018, NASA will launch two new satellite missions that will be critical to improving future sea level projections: the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission, a partnership with GeoForschungsZentrum (GFZ) in Germany, will continue measurements of the mass of the Greenland and Antarctic ice sheets; while the Ice, Cloud, and land Elevation Satellite-2 (ICESat-2) will make highly accurate observations of the elevation of ice sheets and glaciers.

Related links:

Cooperative Institute for Research in Environmental Sciences (CIRES): https://cires.colorado.edu/

Ice, Cloud, and land Elevation Satellite-2 (ICESat-2): https://icesat.gsfc.nasa.gov/icesat2/mission_overview.php

Gravity Recovery and Climate Experiment Follow-On (GRACE-FO): https://www.nasa.gov/mission_pages/Grace/index.html

GeoForschungsZentrum (GFZ): https://www.gfz-potsdam.de/startseite/

Images (mentioned), Video (mentioned), Text, Credits: NASA/Sara Blumberg/Goddard Space Flight Center, by Patrick Lynch/Cooperative Institute for Research in Environmental Sciences, by Katie Weeman.

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Eclipse Season Starts for NASA’s SDO

NASA - Solar Dynamics Observatory (SDO) patch.

Feb. 13, 2018

On Sunday, Feb. 11, 2018, NASA’s Solar Dynamics Observatory, or SDO, saw a total solar eclipse in space when Earth crossed its view of the Sun. Also known as a transit, Earth’s passage was brief, lasting from 2:10 a.m. to 2:41 a.m. EST and covering the entire face of the Sun.

Animation above: On Sunday, Feb. 11, 2018, NASA’s SDO saw a total solar eclipse in space. These images were taken in a wavelength of extreme ultraviolet light, a type of light that is typically invisible to our eyes, but is colorized here in purple. Animation Credits: NASA’s Goddard Space Flight Center/SDO/Joy Ng.

So marks the beginning of SDO’s eclipse season — as well as the mission’s eighth launch anniversary. SDO’s eclipse season is a three-week period that comes twice a year near the equinoxes during which Earth blocks SDO’s view of the Sun for a short while each day. The eclipses are fairly short near the beginning and end of the season but ramp up to 72 minutes in the middle.

NASA’s Solar Dynamics Observatory, or SDO. Image Credits: NASA/GSFC

Most spacecraft observing the Sun from an orbit around Earth have to contend with such eclipses. SDO’s orbit is designed to maximize the amount of data the spacecraft can send back to Earth, but twice a year Earth gets in the way of the spacecraft’s view. The spring eclipse season began on Feb. 10 with a partial eclipse and concludes March 5, 2018.

NASA’s Solar Dynamics Observatory (SDO): http://nasa.gov/sdo and http://www.nasa.gov/mission_pages/sdo/main/index.html

Animation (mentioned), Image (mentioned), Text, Credits: NASA/Rob Garner/Goddard Space Flight Center, by Lina Tran.

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Progress Cargo Craft Launches on Two-Day Trip to Station

ROSCOSMOS - Russian Vehicles patch.

February 13, 2018

Image above: The Progress 69 resupply rocket lifts off in below freezing weather from the Baikonur Cosmodrome in Kazakhstan.Image Credits: Roscosmos/NASA.

Carrying more than three tons of food, fuel and supplies for the International Space Station Expedition 54 crew, the Progress 69 cargo spacecraft launched at 3:13 a.m. EST (2:13 p.m. local time) from the Baikonur Cosmodrome in Kazakhstan.

At the time of launch, the International Space Station was flying over the south Atlantic north of the Falkland Islands at an altitude of 252 miles. Less than 10 minutes after launch, the resupply ship reached preliminary orbit and deployed its solar arrays and navigational antennas as planned.

Launch of the Soyuz-2.1a with Progress MG-08

The Progress 69 cargo vehicle will dock automatically to the aft port of the Zvezda service module of the station at 5:43 a.m. Thursday, Feb. 15. Watch live coverage beginning at 5 a.m. on NASA Television and the agency’s website: http://www.nasa.gov/live

The new Progress spacecraft will remain at the orbiting laboratory until late August.

Related links:

Expedition 54: https://www.nasa.gov/mission_pages/station/expeditions/expedition54/index.html

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Image (mentioned), Video (Roscosmos), Text, Credits: NASA/Mark Garcia.

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CASC - Twin BeiDou-3 Navigation Satellites Sent into Orbit by Single Rocket

BeiDou Navigation Satellite System patch.

February 13, 2018

Long March 3B launch BeiDou-3 MEO-3 & MEO-4

China sent two satellites into orbit on a single carrier rocket for its domestic BeiDou Navigation Satellite System (BDS) on Monday. The launch took place at 05:03 UTC from the LC2 Launch Complex of the Xichang Satellite Launch Center, Sichuan province. It took over four hours to complete the mission.

The twin satellites, which form a network with four previously launched BeiDou-3 satellites, were the fifth and sixth satellites in the BeiDou-3 family. They entered orbit more than three hours after the launch from the Xichang Satellite Launch Center in southwest China's Sichuan Province.

China Launches Two Beidou-3 Navigation Satellites

The twin satellites were launched by the LM-3B YZ-1 rocket. The launch was the 267th mission for the Long March rocket family.

The MEO satellites are the Medium Earth Orbit component of the third phase of the Chinese Beidou (Compass) satellite navigation system. The satellites are part of a fleet that will expand the system to a global navigation coverage.

BeiDou Navigation Satellite

The Beidou Phase III system includes the migration of its civil Beidou 1 or B1 signal from 1561.098 MHz to a frequency centered at 1575.42 MHz – the same as the GPS L1 and Galileo E1 civil signals – and its transformation from a quadrature phase shift keying (QPSK) modulation to a multiplexed binary offset carrier (MBOC) modulation similar to the future GPS L1C and Galileo’s E1.

For more information about China Aerospace Science and Technology Corporation (CASC), visit: http://english.spacechina.com/n16421/index.html

Images, Video, Text, Credits: CASC/Günter Space Page/CCTV+/Orbiter.ch Aerospace.

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NASA TV Covers Russian Resupply Mission Tuesday Morning

ISS - Expedition 54 Mission patch.

February 12, 2018

Loaded with three tons of food, fuel and supplies, a Russian Progress cargo spacecraft is scheduled to launch at 3:13 a.m. EST (2:13 p.m. Baikonur time) Tuesday, Feb. 13, to resupply the International Space Station. The previous launch attempt on Feb. 11 was automatically aborted shortly before liftoff.

The rescheduled launch from the Baikonur Cosmodrome in Kazakhstan will be carried live on NASA Television and the agency’s website beginning at 2:45 a.m.

Image above: The Progress 69 cargo craft stands at its snow-covered launch pad at the Baikonur Cosmodrome in Kazakhstan. Image Credit: Roscosmos.

The Progress 69 cargo vehicle will dock automatically to the aft port of the Zvezda service module of the station two days later at 5:43 a.m. Thursday, Feb. 15. NASA TV and web coverage will begin at 5 a.m. The new Progress spacecraft will remain at the orbiting laboratory until late August.

Related links:

NASA TV: https://www.nasa.gov/multimedia/nasatv/index.html

Expedition 54: https://www.nasa.gov/mission_pages/station/expeditions/expedition54/index.html

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Image (mentioned), Text, Credits: NASA/Mark Garcia.

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Mars Reconnaissance Orbiter Preparing for Years Ahead

NASA - Mars Reconnaissance Orbiter (MRO) patch.

February 12, 2018

NASA's Mars Reconnaissance Orbiter (MRO) has begun extra stargazing to help the space agency accomplish advances in Mars exploration over the next decade.

The spacecraft already has worked more than double its planned mission life since launch in 2005. NASA plans to keep using it past the mid-2020s. Increased reliance on a star tracker, and less on aging gyroscopes, is one way the mission is adapting to extend its longevity. Another step is wringing more useful life from batteries. The mission's extended service provides data relay from assets on Mars' surface and observations with its science instruments, despite some degradation in capabilities.

Bird's Eye View of Mars

Image above: Artist concept of Mars Reconnaissance Orbiter. Image Credits: NASA/JPL.

"We know we're a critical element for the Mars Program to support other missions for the long haul, so we're finding ways to extend the spacecraft's life," said MRO Project Manager Dan Johnston of NASA's Jet Propulsion Laboratory, Pasadena, California. "In flight operations, our emphasis is on minimizing risk to the spacecraft while carrying out an ambitious scientific and programmatic plan." JPL partners with Lockheed Martin Space, Denver, in operating the spacecraft.

In early February, MRO completed its final full-swapover test using only stellar navigation to sense and maintain the spacecraft's orientation, without gyroscopes or accelerometers. The project is evaluating the recent test and planning to shift indefinitely to this "all-stellar" mode in March.

From MRO's 2005 launch until the "all-stellar" capability was uploaded as a software patch last year, the spacecraft always used an inertial measurement unit -- containing gyros and accelerometers -- for attitude control. At Mars, the orbiter's attitude changes almost continuously, with relation to the Sun and other stars, as it rotates once per orbit to keep its science instruments pointed downward at Mars.

The spacecraft carries a spare inertial measurement unit. The mission switched from the primary unit to the spare after about 58,000 hours of use, when the primary began showing signs of limited life several years ago. The spare shows normal life progression after 52,000 hours, but now needs to be conserved for when it will be most needed, while the star tracker handles attitude determination for routine operations.

The star tracker, which also has a backup on board, uses a camera to image the sky and pattern-recognition software to discern which bright stars are in the field of view. This allows the system to identify the spacecraft's orientation at that moment. Repeating the observations up to several times per second very accurately provides the rate and direction of attitude change.

"In all-stellar mode, we can do normal science and normal relay," Johnston said. "The inertial measurement unit powers back on only when it's needed, such as during safe mode, orbital trim maneuvers, or communications coverage during critical events around a Mars landing." Safe mode is a precautionary status the spacecraft enters when it senses unexpected conditions. Precise attitude control is then essential for maintaining communications with Earth and keeping the solar array facing the Sun for power.

To prolong battery life, the project is conditioning the two batteries to hold more charge, reducing demand on the batteries, and is planning to reduce the time the orbiter spends in Mars' shadow, when sunlight can't reach the solar arrays. The spacecraft uses its batteries only when it is in shadow, currently for about 40 minutes of every two-hour orbit.

The batteries are recharged by the orbiter's two large solar arrays. The mission now charges the batteries higher than before, to increase their capacity and lifespan. It has reduced the draw on them, in part by adjusting heater temperatures before the spacecraft enters shadow. The adjustment preheats vital parts while solar power is available so the heaters' drain on the batteries, while in shadow, can be reduced.

Slight Blurring in Newer Image from Mars Orbiter

Image above: These two frames were taken of the same place on Mars by the same camera before (left) and after some images from the camera began showing unexpected blur. The images are from the HiRISE camera on NASA's Mars Reconnaissance Orbiter. They show a patch of ground about 500 feet wide in Gusev Crater.Image Credits: NASA/JPL-Caltech/UA.

The near-circle of MRO's orbit stays at nearly the same angle to the Sun, as Mars orbits the Sun and rotates beneath the spacecraft. By design, as the orbiter passes over the sunlit side of the planet during each orbit, the ground beneath it is about halfway between noon and sunset. By shifting the orbit to later in the afternoon, mission managers could reduce the amount of time the spacecraft spends in Mars' shadow each orbit. NASA's Mars Odyssey spacecraft, older than MRO, successfully did this a few years ago. This option to extend battery life would not be used until after MRO has supported new Mars mission landings in 2018 and 2021 by receiving transmissions during the landers' critical arrival events.

"We are counting on Mars Reconnaissance Orbiter remaining in service for many more years," said Michael Meyer, lead scientist of NASA's Mars Exploration Program at the agency's Washington headquarters. "It's not just the communications relay that MRO provides, as important as that is. It's also the science-instrument observations. Those help us understand potential landing sites before they are visited, and interpret how the findings on the surface relate to the planet as a whole."

MRO continues to investigate Mars with all six of the orbiter's science instruments, a decade after what was initially planned as a two-year science mission to be followed by a two-year relay mission. More than 1,200 scientific publications have been based on MRO observations. Teams operating the two instruments named most often in research papers -- the High Resolution Imaging Science Experiment (HiRISE) camera and the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) mineral-mapper -- are dealing with challenges but are ready to continue providing valuable observations.

For example, some HiRISE images taken in 2017 and early 2018 show slight blurring not seen earlier in the mission. The cause is under investigation. The percentage of full-resolution images with blurring peaked at 70 percent last October, at about the time when Mars was at the point in its orbit farthest from the Sun. The percentage has since declined to less than 20 percent. Even before the first blurred images were seen, observations with HiRISE commonly used a technique that covers more ground area at half the resolution. This still provides higher resolution than any other camera orbiting Mars -- about 2 feet (60 centimeters) per pixel -- and little blurring has appeared in the resulting images.

Using two spectrometers, CRISM can detect a wide range of minerals on Mars. The longer-wavelength spectrometer requires cooling to detect signatures of many minerals, including some associated with water, such as carbonates. To do this during the two-year prime science mission, CRISM used three cryocoolers, one at a time, to keep detectors at minus 235 Fahrenheit (minus 148 Celsius) or colder. A decade later, two of the cryocoolers no longer work. The last has become unreliable, but is still under evaluation after 34,000 hours of operation. Without a cryocooler, CRISM can still observe some near-infrared light at wavelengths valuable for detecting iron oxide and sulfate minerals that indicate past wet environments on Mars.

The Context Camera (CTX) continues as it has throughout the mission, adding to near-global coverage and searching for changes on the surface. The Shallow Radar (SHARAD) continues to probe the subsurface of Mars, looking for layering and ice. Two instruments for studying the atmosphere -- the Mars Color Imager (MARCI) and Mars Climate Sounder (MCS) -- continue to build on nearly six Mars years (about 12 Earth years) of recording weather and climate.

The University of Arizona operates HiRISE, which was built by Ball Aerospace & Technologies Corp., Boulder, Colorado. The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, leads MRO's CRISM investigation. The Italian Space Agency provided SHARAD. Malin Space Science Systems, San Diego, built and operates CTX and MARCI. JPL, a division of Caltech in Pasadena, California, manages the MRO Project for the NASA Science Mission Directorate in Washington and leads the MCS investigation. Lockheed Martin Space built the spacecract.

Mars Reconnaissance Orbiter (MRO): http://www.nasa.gov/mission_pages/MRO/main/index.html

Images (mentioned), Text, Credits: NASA/Laurie Cantillo/Dwayne Brown/JPL/Guy Webster/Andrew Good.

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Russian Cargo Mission to Station is Scrubbed

ROSCOSMOS - Russian Vehicles patch.

February 11, 2018

Image above: Russia’s Progress 69 resupply ship is pictured standing at its launch pad at the Baikonur Cosmodrome in Kazakhstan shortly after its roll out Feb. 9, 2018. Image Credit: Roscosmos.

The planned launch of the Progress 69 cargo spacecraft at 3:58 a.m. EST (2:58 p.m. local time) from the Baikonur Cosmodrome in Kazakhstan has been scrubbed. Rescheduled for February 13, 2018.

Related links:

Expedition 54: https://www.nasa.gov/mission_pages/station/expeditions/expedition54/index.html

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Image (mentioned), Text, Credits: NASA/Mark Garcia.

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