An artist’s conception of the Landsat 9 spacecraft, the ninth satellite launched in the long-running Landsat program, high above the agricultural fields in California’s Central Valley and the Western US. Credit: NASA’s Goddard Space Flight Center / Conceptual Image Lab
by Jenny Marder //VANDENBERG SPACE FORCE BASE, CALIFORNIA//
It’s less than four days before the planned launch of Landsat 9, and the perfect time to learn about this amazing satellite and the nearly 50-year-old Landsat program. Did you know:
Landsat gives us the longest continuous space-based record of planet Earth.
Since the first satellite launched in July 1972, the mission’s eight satellites provide five decades of information about our planet’s land and atmosphere. And they show us how our planet is changing. This will continue with the Landsat 9 launch, providing more data and higher imaging capacity than past Landsats.
Landsat 9 will carry two science instruments …
The Operational Land Imager 2, or OLI-2, sees at a spatial resolution of 49 feet for its panchromatic band, which is sensitive to a wide range of wavelengths of light, and 98 feet for the other multispectral bands. Its image swath is 115 miles wide, with enough resolution to distinguish land cover features like urban centers, farms and forests.
The Thermal Infrared Sensor 2, also known as TIRS-2, measures land surface temperature in two thermal infrared bands using principles of quantum physics to measure emissions of infrared energy.
… and it will orbit the Earth at an altitude of 438 miles.
That’s roughly the distance between Dallas and Memphis.
Landsat has shown us how dynamic the planet is in response to human activities.
“When you grow up in an area, you don’t really notice the changes that occur over years and decades,” Dr. Jeff Masek, NASA Goddard’s Landsat 9 Project Scientist, told Dr. Alok Patel in December 2020 for PBS’s NOVA Now podcast. “But when you run the movie in fast motion, suddenly we see all these changes: urbanization and changes in forest management, areas where agricultural irrigation suddenly goes into desert environments.”
Watch this video for a Landsat roadtrip through time.
You’ll learn about the first game-changing launches in the 1970s, the advent of natural color composite images in the 1980s, the increased global coverage in the 1990s, the move to free and open data archives in the 2000s, the modern era of Landsat observations in the 2010s, and now, the launch of Landsat 9 in 2021.
And follow us here and on Twitter @NASAExpeditions this week as we count down to Landsat 9’s launch!
ER-2 takeoff on 16 July 2021 for DCOTSS Research Flight 01. Photo credit: Dan Chirica
By Rei Ueyama, NASA Ames Research Center /SALINA, KANSAS/
It’s 3 a.m. in Salina, Kansas. The moon is out. Crickets are chirping on this balmy summer night. The light above the door to the hangar softly illuminates the sign that reads “DCOTSS.” Most teammates are just waking up. I unlock the door and walk in to be the first to start this long but exciting day full of new discoveries. It’s yet another start of a typical day of a forecaster for the NASA Dynamics and Chemistry of the Summer Stratosphere (DCOTSS) field campaign.
A picture of the door to the hangar taken by me (Rei Ueyama) on the morning of DCOTSS Research Flight 04 on 26 July 2021.
About 50 of us have gathered here (and 20 more to arrive later) in the middle of the continental United States in search of strong convective storms that penetrate high into the atmosphere. These so-called overshooting storms carry water and pollutants from the boundary layer and troposphere (where we live) into the atmospheric layer above us called the stratosphere. Small turrets at the top of these strong storms overshoot into the stratosphere, and hence its name “overshoots”.
The stratosphere is a much different environment than the troposphere. For one, it is extremely dry. It also has many molecules of ozone that make up the ozone layer which protects us from harmful ultraviolet rays. Various materials pumped up from the troposphere into the stratosphere by these overshooting storms may alter the chemistry and composition of the stratosphere, which could ultimately affect Earth’s climate quite significantly. So we’re here to find out exactly how and to what extent these strong convective storms influence our climate.
ER-2 pilot (Greg “Coach” Nelson) stepping into the aircraft for DCOTSS Research Flight 01 on 16 July 2021. Photo credit: Dan Chirica
Our vehicle for exploration is NASA’s ER-2 high-altitude research aircraft. The ER-2 is a single-occupant, lightweight airplane with a long (31.5 meter) wingspan that flies gracefully at altitudes up to 70,000 feet in the stratosphere, which is about twice the altitude of commercial airplanes. Air is so thin at those high altitudes that the pilot must wear a pressurized spacesuit in case of a loss of cabin pressure. Inside the nose, body and pods under each wing is like a jigsaw puzzle of many scientific instruments. Each instrument measures specifics gases in the atmosphere which are later analyzed to hopefully tell us a story about how convective storms affect the stratosphere.
A picture of forecasting and flight planning meeting on the morning of 15 July 2021. I am sitting in the front left corner (my back facing the camera), leading the meeting. Photo credit: Dan Chirica
My role in DCOTSS is to lead a group of forecasters and flight planners to provide our best assessment of where the outflow plumes from overshooting storms may be located on the day of a science flight and then design a flight plan to sample those plumes. This is no easy feat as these plumes of overshooting material are often tenuous and sparse such that our effort often feels like a search for a diamond in a haystack.
As we rub our just-awoken eyes and scrutinize the early morning images of overshooting plume forecasts from satellite and radar-based models, the instrument scientists begin to arrive at the hangar to prepare their instruments for a 6 to 7 hour flight. The flight plan is tweaked, the pilot is briefed, and we are ready to go.
A picture of non-overshooting convective storms reaching up to 45 kft taken by the pilot (Gary “Thor” Toroni) on DCOTSS Research Flight 02 on 20 July 2021. Photo credit: Gary “Thor” Toroni
Watching the pilot navigate the ER-2 just as we had planned is very humbling and satisfying. But at the same time, our nerves are running high as the measurements from the instruments start to trickle in from the aircraft to the mission operation center on the ground. How good was our plume forecast? Do we see any indication in the measurements that the ER-2 had actually flown through a convective plume? On many occasions, it’s too early to tell. The diamond usually only shines through after the flight has been completed and after a thorough analysis of the collective measurements. Yet we are glued to our computer screens, holding our breath as we look for any signs of a convective plume in the real-time measurements.
Our job is mostly done for today, but there is no reprieve. We now look into the future to plan our next science flight. Time to hunt for another overshooting storm!
Gemma Narisma with NASA’s P-3 research aircraft during the 2019 CAMP2Ex deployment in the Phillipines. Credit: NASA
By Katy Mersmann, NASA
We’re so saddened by the loss of our teammate Dr. Gemma Teresa Narisma. She was a passionate climate researcher and the Philippine lead for the Cloud, Aerosol, and Monsoon Processes Philippines Experiment (CAMP2Ex).
As the director of the Manila Observatory and a professor at Ateneo de Manila University, she not only helped plan the research, but she aggressively brought students into the CAMP2Ex project, helping lead the next generation of meteorologists and climate researchers in forecasting weather for flights and data collection.
“We witnessed brightness, peace, curiosity, joy, courage and determination,” Simone Tanelli of NASA’s Jet Propulsion Laboratory said, in Gemma’s remembrance. “And Gemma was right at the center of that, emanating them, and the whole Manila Observatory team shone with them.”
Gemma’s expertise was internationally recognized: She served as an author on the Intergovernmental Panel on Climate Change’s (IPCC) Sixth Assessment Report and received numerous awards honoring her work as a researcher. Gemma was one of the leading subject matter experts in the Philippines on climate resilience, severe weather and natural hazards. She was consulted at every level of the Philippine government.
Gemma was a dedicated and enthusiastic teammate and mentor; a role model for younger scientists and a friend to all who met her. Her smile lit up a hangar, and it was a joy to watch her celebrate as her students took their first science flights with CAMP2Ex.
“The world has lost a valuable scientist, and the Philippines has lost an environmental spokeswoman, but we have lost a beloved friend” said Jeffrey Reid, U. S. Naval Research Laboratory.
NASA’s ACTIVATE mission recently began its second year of flights. Here, final preparations are being made to the HU-25 Falcon prior to a flight. Credits: NASA/David C. Bowman
By Joe Atkinson / NASA’S LANGLEY RESEARCH CENTER, HAMPTON, VIRGINIA/
A NASA airborne study has returned to the field for a second year of science flights to advance the accuracy of short- and long-term climate models.
Cloud formation in the atmosphere depends on the presence of tiny particles called aerosols. ACTIVATE scientists are working to understand how variations in these particles from human and natural sources affect low lying clouds over the ocean and how those clouds in turn affect the removal of these particles from the atmosphere.
A bit of snow fell before the DC-3 plane took off for another day of dropping probes into the waters around Greenland. Credit: Josh Willis/JPL
By Lara Streiff
Despite racing against impending harsh weather conditions, a red and white World War II aircraft flew slowly and steadily over the icy waters surrounding Greenland in August and September. Three weeks delayed by pandemic restrictions, scientists from NASA’s Jet Propulsion Laboratory inside this retrofitted DC-3 plane started dropping hundreds of probes as part of an annual expedition known as the Oceans Melting Greenland (OMG) Project.
Since 2016, the OMG project has conducted numerous flights over the waters near Greenland’s lengthy and jagged coastline. They drop roughly 250 probes each year (though they managed a record 346 during this extraordinary 2020 expedition) which then relay temperature and salinity data. The team uses this information to help determine how much the surrounding ocean is contributing to Greenland’s ice melt.
“The glaciers are reacting very strongly to the ocean and we ignore that at our peril,” said JPL scientist and principal investigator Josh Willis. “The oceans have the potential to melt the ice very quickly and drive the sea level rise even higher than we expected.”
If it all melted, Greenland’s ice could contribute as much as 25 feet of sea level rise—though Willis assures us that this is not expected within the next year, or even the next 100 years. The big question that his team is trying to help answer is rather the speed at which the ice is melting.
In the northwest of Greenland, where the Upernavik glacier meets the Atlantic. Credit: Josh Willis/JPL
Unlike icebergs—which float in water—glaciers sit atop a land mass, seemingly exposed and vulnerable to the warming atmosphere. While the atmosphere is a significant factor, it is not solely responsible for glacial melt. As the glaciers in Greenland start to ooze off the island in massive rivers of ice, they carve fjords into the landscape until they finally connect with the sea. While surface waters are generally frigid, the warmer ocean waters from below can cause the glacier to melt more quickly and speed up the amount of ice that drains off the land into the ocean.
Though the coronavirus pandemic had sweeping impacts across the globe, it didn’t halt environmental processes like Greenland’s glacial ice melt. It also didn’t impede the resolve of the OMG scientists to continue their work.
Starting in March up until the day they landed in Greenland on August 24, Willis says he wasn’t sure they would be able to collect their data this year. But cooperation between the various stakeholders, including NASA, the State Department, and the governments of Canada and Greenland, was key. Willis also gives credit to a huge amount of hard work by OMG’s Project Manager, Ian McCubbin of JPL, for making it possible. “If it wasn’t for McCubbin,” said Willis, “we’d still be sitting on our couches.”
Coordinating the scientists and equipment necessary for any expedition requires a great deal of planning, and the additional pandemic-related precautions made everything just a little bit more complicated.
“It was like a whole new layer, after you go across the border and go through customs and boarder control, now you also go through coronavirus screening,” Willis said.
Oceans Melting Greenland lead scientist Josh Willis getting tested for COVID-19 while in Greenland. Credit: Josh Willis/JPL
In addition to getting tested a whopping seven times, two of which took place before even stepping foot in Greenland, Willis and the other members of the OMG team were very cautious. There was an initial isolation period after landing on the island during which they could fortunately work on the plane and equipment preparation, wearing masks when traveling to and from the site and no contact with locals. Greenland has had very few cases of COVID, and doesn’t have enough hospitals to handle any outbreaks, so the team was especially conscious of limiting their interactions with people there.
One exception was communicating with the nurses conducting their COVID-19 tests. “It was quite an experience getting tested this many times,” said Willis, “but the most fun was actually with nurses in Greenland, who were very nice and asked about our mission, so we got to tell them about what OMG was doing—and I suspect they followed along the rest of our journey on social media.”
Though some legs of the scientists’ expedition were delayed or more challenging as a result, Willis says it was well worth the extra effort to ensure everyone’s safety.
The outcome turned out to be a banner year for the project, despite the late start. Instead of heading north at the beginning of the month, it was already well into August when Project Manager Ian McCubbin and the three scientists from JPL—Ian Fenty, Mike Wood, and Willis himself—were able to meet with their flight crew from Kenn Borek Air.
The crew after their successful season. In the photo from left to right: Josh Willis, OMG lead scientist; Mike Wood, OMG scientist; Linden Hoover, Kenn Borek co-pilot; Jim Haffey, Kenn Borek pilot; and Ian Fenty, OMG scientist. Not pictured are Gerald Cirtwell, Kenn Borek flight engineer, and Ian McCubbin, OMG project manager. Credit: Josh Willis/JPL
Once they were on the ground in Greenland, their main concern was for the conditions they might encounter once back in the air.
“Weather starts to get pretty rough in September, and very rough in October.” said Willis. Fortunately, they were able wrap up their surveys by mid-September, mostly dodging the snow, sleet and wind that might impede their ability to drop all of the probes. “It was a sprint to the finish line, but we were able to accomplish everything we wanted to do and more.”
In fact, the team encountered unusually good conditions in the north east parts of the island, where ice and fog usually prevent access. As a result, they measured some glaciers that had never been sampled before.
When the project first began in 2016, the scientists also flew a jet with a radar strapped on the bottom to measure big swaths of glaciers from above, but NASA’s ICESat-2, an Earth-observing satellite that measures the mass of ice sheets and glaciers down to the inch that launched in 2018, takes care of that part of the mission now.
More than 45 scientific papers have now been published based on OMG data, with several more in progress. Willis says that every new discovery reminds them that the oceans are more important than they ever thought possible.
This year they noted new observations of Greenland’s largest glacier Jakobshavn, which has been closely monitored since the start of the project in 2016. In the first couple of years, the water near Jakobshavn cooled by 2.7 degrees Fahrenheit (1.5 degrees C)—a whole lot for a block of ice according to Willis. That cooling slowed the melting of the glacier, which then started growing instead. But early this year warm water returned to Jakobshavn and the recent observations suggest it is now thinning once again.
The view of Greenland’s Jakobshavn glacier from the DC-3 plane which carries the Oceans Melting Greenland Project scientists. Credit: Josh Willis/JPL
These continued discoveries from the project are very exciting for the scientists and organizations involved. Because of this, the OMG project has gotten approval to continue its research beyond the original end date, meaning that Willis and his crew will again be making their way back to Greenland next August, and this time hopefully without much delay.
Masks are part of the safety protocol for ACTIVATE scientists. Here, Yonghoon Choi prepares for a science flight on the HU-25 Falcon. Credits: NASA/David C. Bowman
By Joe Atkinson / NASA’s Langley Research Center, Hampton, Virginia/
Four months ago, with COVID-19 disrupting life across the globe, it seemed virtually unthinkable that a major NASA airborne science campaign would fly again anytime soon.
Those flights are taking scientists over the western Atlantic Ocean to study how atmospheric aerosols and meteorological processes affect cloud properties. In addition, modelers will use data from these flights to better characterize how the clouds themselves, in turn, affect aerosol particle properties and the amount of time they spend in the atmosphere, as well as the meteorological environment. Coordinated flights between a King Air and an HU-25 Falcon allow researchers to fly above, below and through the clouds with a suite of instruments that can take measurements remotely, or from the air around the aircraft.
The HU-25 Falcon sits on the tarmac just ahead of a flight. Credits: NASA/David C. Bowman
“The data have been really good so far,” Armin Sorooshian, ACTIVATE principal investigator and an atmospheric scientist at the University of Arizona, said of the summer flights. “We’ve seen some interesting features, like smoke from the wildfires on the West Coast.”
That smoke can seed clouds over the Atlantic Ocean.
Sorooshian is leading the campaign remotely from his home in Tucson, Arizona, where he and his wife are juggling work and the care of two children — a two-year-old boy and a baby girl who was born in July.
He admits it’s “a little tough.” But in a world where these flights could have been scrubbed from the calendar completely, Sorooshian isn’t interested in dwelling on the negatives.
“They’re good problems,” he said.
Good Problems
The ACTIVATE team began the first of two planned 2020 flight campaigns in February. They completed most of those flights, but had to pull the plug a little early in mid-March when concerns about the spread of COVID-19 began to sweep across the U.S. At that point, the fate of the second set of flights, originally scheduled for May and June, was — pardon the pun — very much up in the air.
As the COVID situation evolved, though, and as Langley leadership began to admit a limited number of research projects back on center with stringent safety protocols in place, it became clear there might be a glimmer of hope for ACTIVATE.
ACTIVATE is uniquely positioned among other current NASA airborne science missions because it’s based out of a NASA center, and the flight crew and many members of the science team are also based out of that center. John Hair, ACTIVATE project scientist with Langley’s Science Directorate, knew that from a purely logistical perspective, the mission could return to flight without the need for anyone to travel in from out of town.
“We had an opportunity because ACTIVATE has a relatively small crew that can operate the instruments in the aircraft, and do that, we felt, safely — albeit with some changes to the initial plans we set out,” he said.
Besides obvious stuff such as wearing masks and being mindful of social distancing, those changes include conducting the various daily flight planning meetings and pre-flight briefings completely via video conference. Researchers are also doing real-time monitoring of flight data from their homes. For researchers who are flying or need to be on center, the project has found ways to streamline some processes.
“For example, people are learning how to do their calibrations at the end of the flight after the instruments are already warmed up,” said Hair. “And then it only takes an hour to do.”
Compare that to the three or four hours it can take a researcher to warm up and calibrate an instrument before a flight.
The King Air rolls out of the hangar before a science flight. Credits: NASA/David C. Bowman
The entire operation has taken a lot of careful planning and coordination between Langley’s Science Directorate, Research Services Directorate and Center Operations Directorate. Sheer determination has certainly played a role as well.
“We all signed up for supporting research as it comes in. ACTIVATE was in the middle of a major campaign and we wanted to get them back to flying as soon as we could,” said Taylor Thorson, ACTIVATE project pilot with Langley’s Research Services Directorate.
Sorooshian believes this experience could be instructive for the next round of flights, which are currently scheduled to kick off in February 2021 when COVID-19 could still be a significant concern.
It’s not just instructive from a safety perspective. Marine clouds are more scattered and difficult to forecast in the summer.
“Flying this summer also allows the team to hone the flight planning strategies, which can build upon heading into the next two years of flight campaigns,” he said.
For now, he and Hair are just happy to see a study they both care deeply about back in action.
“This is exciting that we’re out doing some flights,” said Hair. “People are excited to get the critical science data that we’re collecting on these flights.”
The ACTIVATE science team includes researchers from NASA, the National Institute of Aerospace, universities, Brookhaven National Laboratory, Pacific Northwest National Laboratory, the National Center for Atmospheric Research and the German Aerospace Center. The current flight campaign is the second of two in 2020, with two more to follow in 2021, and another two in 2022.
The German icebreaker Polarstern lit up on every deck, acting as a beacon for researchers navigating the Arctic terrain. Credit: University of Maryland / Steven Fons
By Emily Fischer, Goddard Space Flight Center
In the early 1900s, Ernest Shackleton attempted to travel across Antarctica, but as they neared the continent his ship became stuck in an pack of sea ice and was slowly crushed before it reached the landmass. Over 100 years later and on the opposite side of the globe in the Arctic, researchers in the massive, double-hulled icebreaker, Polarstern, are also stuck in a pack of sea ice – but this time on purpose. And this ship isn’t sinking any time soon.
Polarstern is the operational center for the Multidisciplinary drifting Observatory for the Study of Arctic Climate, or MOSAiC. The first expedition of its kind, MOSAiC is an international mission exploring the Arctic climate system year-round, with more than 100 scientists and crew members from 20 nations living aboard the research vessel.
Intentionally trapping itself in the sea ice, Polarstern drifts with the floe, which is a large pack of floating sea ice. Researchers set up “little cities” on the ice where they take measurements using delicate instruments. While it appears that the sea ice they walk on to reach these camps is stationary, everything is actually slowly drifting as wind and ocean currents push the gigantic slabs of ice.
Steven Fons (bottom row, second from the right) and his ice coring team after successfully drilling sea ice samples. Each core will be analyzed at the labs aboard Polarstern. Credit: University Center in Svalbard / Calle Schönning
MOSAiC is a multidisciplinary expedition, as researchers from a variety of fields – including marine biology, meteorology, and oceanography – collaboratively study Arctic changes.
“It’s more of a process study,” explained Steven Fons, a Ph.D. candidate at the University of Maryland and NASA’s Goddard Space Flight Center, who studied sea ice from March to May of this year. “The idea, then, is once everybody collects this data, we can compile everything and learn about the sea ice in the ocean, and the atmosphere and the ecology.”
Sea ice is an integral part of the Arctic climate system because it sits directly between the ocean and the atmosphere, moderating the exchange of heat and moisture. An important climate indicator, sea ice research identifies changes in other Arctic climate systems, including the ocean, atmosphere, ecology, and biogeochemical cycles. Basically, studying sea ice can give greater insight into how the entire Arctic is reacting to climate change.
Researchers haul their equipment to their field sites through snow blown by harsh winds. One researcher, a polar bear guard, carries a rifle on his back in case of an emergency. Credit: Alfred Wegener Institute / Delphin Rouché
For a small group of MOSAiC researchers, every Monday was a 14-hour workday spent at “Dark Sites,” named so because they are isolated from the bright lights of Polarstern. After traveling over a mile on snow machine, the team used hollow drills to remove cylindric cores from the sea ice floe. In the labs aboard Polarstern, these samples revealed the fascinating characteristics of sea ice.
“As ice forms, it will eject the salt away as it’s freezing,” said Fons. “The longer it stays around, the more salt essentially drains out of it.” Basically, high salt levels tell researchers that this particular ice formed in the most recent winter. This can reveal how the Arctic adjusts to higher temperatures, as the region is warming at a rate more than twice the global average.
In the Arctic, wind chill can reach frigid temperatures as low as minus 70 degrees Fahrenheit. Working in the cold without hand protection was impossible, so Fons wore thin gloves underneath his bulky mittens, which he removed when handling small objects. Even so, frequent warming breaks were necessary, which meant simple, one-minute tasks could take 10 times longer in Arctic conditions.
“Some of the really cold days, you can only last 30 seconds at a time taking off your big mittens,” he recounted. “You just have to put five zip ties on this cable, perfect. It should take one minute to do, but it would take 20 minutes because you have to keep warming your hands and [the zip ties] keep breaking in the cold.”
Native to Wisconsin, Fons is no stranger to subzero winters. Nonetheless, during this expedition he witnessed temperatures unlike anything he had ever experienced before. Icy winds bit into any exposed skin. His only relief: a thick, bushy beard and about ten layers of clothing.
Steven Fons bundles up in the subzero temperatures with a fur-lined hat, multiple face-coverings, and nine or ten layers underneath his protective jacket. Credit: University Center in Svalbard / Calle Schönning
In an ever-changing environment, researchers’ locations can be difficult to determine on the ice cover, which can literally shift beneath their feet. For MOSAiC, every measurement is paired with a GPS coordinate. However, the ice drifts, and so the latitude and longitude change every day. Instead, the immense icebreaker Polarstern is used as a point of reference, a sort of ground zero for field navigation.
“You’re given a position away from the ship, so a certain distance of x and y, and that will theoretically never change,” Fons explained. But even this system has its obstacles. “If the ice broke up and the ship moves a little bit, then you can lose your x-y positions, so it didn’t always work.”
Helicopters and planes accompany Polarstern, getting a birds-eye view of the stark white landscape. Flying high above the floe, planes take airborne measurements in a similar way to Operation IceBridge. Fons does research using data from NASA’s ICESat-2 – the satellite that surveys glaciers and sea ice around the globe – and he was lucky enough to validate some of the satellite’s measurements while researching with MOSAiC.
“On the ship, since we’re constantly drifting with the ice, we don’t exactly know where we’re going to be on any given day,” he said. “We got lucky that we happened to be drifting one day over a spot that ICESat-2 was going to fly over. We were able to jump on that opportunity and schedule a helicopter flight.”
Seasonal changes near the poles are unlike anywhere else on Earth. Summer and winter are really the only seasons these regions experience, characterized by a dramatic transition between complete darkness during winter days to total sunlight during the summer. Ten days after reaching Polarstern, Fons witnessed his first Arctic sunrise. As summer came, the Sun sailed over the horizon for longer and longer each day until it refused to set, resulting in the phenomenon of the “midnight sun.”
The Sun at midnight on a day when it never dipped below the horizon. The North Pole, referred to as the land of the midnight sun, experiences about five months of total darkness and about six months of never-ending sunlight. Credit: University of Maryland / Steven Fons
Ice dynamics, or the movement of ice slabs in the floe that changes the terrain, were a trademark of Fons’ three months on Polarstern. Sometimes, the researchers would wake up to massive leads, or ice fractures, blocking their usual routes. Other days, research tents would be buried in ice piles from leads that closed to form towering ridges. Sea ice dynamics had a wide appeal for study among MOSAiC teams. Below the floe, marine biologists and ecologists studied microorganisms. Within the ice itself, sea ice researchers examined crystallization patterns.
“With MOSAiC, what people are able to do is look at the ice at so many different scales and through many different lenses,” Fons summarized.
An ice lead converged to form a ridge of precariously piled slabs of ice. Credit: University of Maryland / Steven Fons
Jacques Cousteau and his team of expert divers were a key part of the success of the 1975 NASA-Cousteau Bathymetry Experiment. In this photo from left to right: Bernard Delemotte, Chief Diver; Henri Garcia; Jean-Jérome Carcopin, and Jacques Cousteau. Photo credit: The Cousteau Society (preserved as large format photo at NASA’s Goddard Space Flight Center)
By Laura Rocchio, Goddard Space Flight Center
Leaving from Nassau on a Tuesday night in August 1975, Jacques Cousteau and his team set out on the Calypso for a three-week expedition designed to help NASA determine if the young Landsat satellite mission could measure the depth of shallow ocean waters.
For days, the Calypso played leapfrog with the Landsat 1 and 2 satellites in the waters between the Bahamas and Florida. Each night, it sailed 90 nautical miles to be in position for the morning overpass of the satellite.
Ultimately, research done on the trip determined that in clear waters, with a bright seafloor, depths up to 22 meters (72 feet) could be measured by Landsat.
The primary test site for the expedition was just west of the Berry Islands on the northern edge of the Great Bahama Bank. The location was chosen as the prime testing site because it gradually changed depth from one meter to deep ocean in a short north-south span (25 nautical miles). This natural-color Landsat 8 image acquired on March 23, 2019, shows where the northern Great Bahama Bank meets the deep ocean. Image credit: NASA/USGS Landsat
This revelation gave birth to the field of satellite-derived bathymetry and enabled charts in clear water areas around the world to be revised, helping sailing vessels and deep-drafted supertankers avoid running aground on hazardous shoals or seamounts.
“It was a tremendous example of how modern tools of scientists can be put together to get a better understanding of this globe we live on,” the Deputy NASA Administrator, George Low, said of the joint Cousteau-NASA expedition in a 1976 interview.
But it couldn’t have happened without the world’s most famous aquanaut, his team of expert divers, and the Calypso.
Astronauts and Aquanauts Together
The ocean’s vastness made Cousteau an early supporter of satellite remote sensing.
Cousteau, by then a decades-long oceanographer, was keenly aware that ocean monitoring from above would be necessary to understand the ocean as part of the interconnected Earth system and to raise the awareness requisite for protecting the sea. There was a growing recognition in the 1970s that helping the planet required understanding the planet.
“Everything that happens is demonstrating the need for space technology applied to the ocean,” Cousteau said during a 1976 interview at NASA Headquarters.
George Low, the Deputy NASA Administrator, himself a recreational diver, connected Jacques Cousteau with former Apollo 9 and Skylab astronaut Russell Schweickart. Schweickart was heading up NASA’s User Services division and both he and Cousteau were looking for ways to advance Earth science.
At the time, it was theorized that the new Landsat satellites might be useful for measuring shallow ocean waters. New deep-drafted supertankers were carrying crude oil around the globe, and to avoid environmental catastrophes it had become important to know where waters in shipping lanes were less than 65 feet (20 meters).
For this experiment, Landsat data was downlinked to NASA Goddard Space Flight Center in Greenbelt, Maryland where it was processed into depth contour data. This was uplinked to the Applications Technology Satellite-3 (ATS-3) and then sent via Very High Frequency (VHF) relay to a VHF receiver system that had been installed on the Calypso for an earlier 1974 experiment in the Gulf of Mexico. Image credit: NASA
To establish if Landsat could accurately measure ocean depth from space, simultaneous measurements from ships, divers and the satellite were needed.
Schweickart knew a coordinated bathymetry expedition was an essential step. He had honed his diving expertise while training for his Skylab mission in NASA’s water immersion facility and was enthusiastic about scuba work. Teaming with Cousteau was a natural fit.
Chasing Satellites
An elaborate experiment was designed to determine definitively if multispectral data from the Landsat satellites could be used to calculate water depth. The clear waters of the Bahamas and coastal Florida were selected as the test site.
The experiment design involved two research vessels, the Calypso and Johns Hopkins University Applied Physics Lab’s Beadonyan, being in position, or “on station,” when the Landsat 1 and 2 satellites went overhead on eight different days (four consecutive days on each of two weeks).
The overall concept was simple: the research ships would use their fathometers to measure water depth at the exact same time that the satellite flew overhead and then those measurements would be compared (the simultaneous measurements eliminated any environmental or atmospheric differences that could have complicated comparisons). But realizing that plan took extraordinary coordination.
A detail from the planning map used for the 1975 NASA-Cousteau Bathymetry Experiment showing the Berry Islands. The hatched lines show the location of Landsat scene edges. Image credit: NASA
As the Landsat satellite flew overhead, Cousteau and his team of divers made a series of carefully timed measurements of water clarity, light transmission through the water column, and bottom reflectivity. This was done both near the Calypso and at two sites 60 meters from the Calypso using small motorized Zodiac rigid inflatable boats.
To make the light transmission measurements, two teams of divers had to use a submarine photometer to measure light at the water’s surface, one meter under the water and in 5-meter increments to the bottom (down to 20 meters).
The divers had to hold the photometer in a fixed position looking up and cycle through four different measurements. They also used specially filtered underwater cameras to measure bottom reflectivity (assisted by gray cards for reference). Everything was carefully timed. Schweickart and President Gerald Ford’s son Jack helped with these underwater measurements.
To make the precision measurements, the skill of these divers – including Cousteau’s chief diver, Bernard Delemotte – was essential.
“I was in charge of the divers,” Delemotte explained in a recent interview. “We were very convinced that we could do serious work together [with NASA].”
Before the satellite overpass, the Calypso and Beayondan were in position, anchored side-by-side, and ready to make all specified measurements.
“Two small Zodiacs left from the Calypso just before the satellite passage,” Delemotte recalls.
The Zodiacs stationed themselves 200 feet (60 meters) from the Calypso, and at the moment that the satellite was overhead someone on the Calypso would call to the divers through the portable VHF radio: “Go now!”
The divers would then start the series of prescribed measurements.
Using these measurements, scientists developed mathematical models describing the relationship between the satellite data and water depth, accounting for how far the light could travel through water, and how reflective the ocean floor was.
“Particular thanks” was given to Cousteau’s team of divers in the experiment’s final report “for their dedication and expertise in the underwater phases of the experiment, without which, measurements of key experimental parameters could not have been made.”
The diving prowess of Cousteau, Delemotte, and the Calypso crew added inextricably to the realm of satellite-derived bathymetry. Because of data collected during the NASA-Cousteau expedition, charts in clear water areas around the world were updated, making sea navigation safer. It was the precision measurements made by Delemotte and Cousteau’s team of divers that made bathymetry calculations for those chart updates possible.
NASA’s high-altitude ER-2 aircraft was part of the IMPACTS field mission to study snow in January and February, 2020. Credit: NASA/Katie Stern
By Katie Stern, IMPACTS’ Deputy Project Manager / HUNTER ARMY AIRFIELD, SAVANNAH, GEORGIA/
“Get in there and check it out!”
I was encouraged by “Corky” Cortes from the NASA ER-2 Life Support Team to see how the pilots prepare for their flight. This was my first NASA field campaign with the ER-2, a high altitude aircraft requiring a Life Support Team to help maintain the health and safety of the pilots. This aircraft is highly specialized and has been modified by NASA for conducting airborne science research.
NASA ground crew preparing the ER-2 for a science flight at Hunter Army Airfield in Savannah, Georgia. There are seven scientific instruments located on the aircraft for the IMPACTS project, used to study snowstorms. Credit: NASA/Katie Stern
As the Deputy Project Manager for the NASA IMPACTS project (Investigation of Microphysics and Precipitation for Atlantic Coast-Threatening Snowstorms), I spent January and February at Hunter Army Airfield in Savannah, Georgia, managing the deployment site for the ER-2 and the mission scientists. Our project is specifically focused on studying snowbands across the Eastern seaboard. The ER-2 plays a critical role in capturing remote sensing data to better predict the severity of storms.
Deputy Project Managers Fran Becker and Katie Stern awaiting the ER-2 science flight. Cross winds were mild and the ER-2 was able to take off. Credit: NASA
As a new member to the team, I was unfamiliar with what the Life Support crew and pilot needed to do before each flight. Determined to find out, I peered into the tiny office and saw Joey Barr from Life Support setting up the dressing area for pilot Cory Bartholomew. The full pressure suit was completely unzipped, its green lining visible. It was laid out on the floor to make the dressing process easier. Shiny black boots with metal stirrups used for the ejection seat were placed neatly on both sides of the vinyl chair. Behind Cory were two bright yellow gloves and a space helmet carefully placed on a donut shaped pillow. Everything was ready to go. All we needed was the pilot.
Prior to every flight, the ER-2 Life Support team lays out all of the equipment to aid in an easier suiting up process. The suits weigh between 35-40 pounds and every pilot wears long underwear inside the suit. It is important to make sure that the pilot does not overheat during the suiting process so the pilots are usually assisted by a Life Support crew member. Credit: NASA/Katie Stern
The actual suiting-up process looked a bit cumbersome. I could see why it would be easy to overheat if you tried dressing yourself. One foot, after another, Cory stepped into the matte yellow and green suit and then poked his head through a metal collar, which was used to secure his space helmet.
The two men worked silently, adjusting the suit, putting on the torso harness, tightening straps, and going over the checklist in their heads. They’ve both been through this routine hundreds of times, but for me it was fascinating to see the thought and care going into each movement.
ER-2 Pilot Cory Bartholomew being helped into his full pressure suit by Joey Barr from the Life Support Team. Credit: NASA/Katie Stern
After a few adjustments to the velcro reading glasses that went inside the helmet, Cory snapped the visor shut, and Joey put on his headset to begin the suit pressure checks. A small yellow box filled with liquid oxygen was then connected to the front of the suit with a hose. These pressurized suits along with the liquid oxygen (LOX) allow pilots to fly at an altitude of 65,000 feet, so high the pilots can see the curvature of the Earth.
Joey Barr making sure that Cory Bartholomew is happy with his glasses. Once the helmet is shut, the pilot will not open the visor again until after landing. Credit: NASA/Katie Stern
A few moments later the suit began to inflate and Cory motioned for me to tap on his knee to feel the outward force from the pressure check. A few more checks were conducted and within 15 minutes Cory was ready to be escorted to the van that would take him out to the aircraft.
“If the pilot has an 8 hour mission, how does he eat or drink once he’s in his suit?” I asked Joey, knowing that it was probably a common question.
“See this small hole at the bottom of the helmet? We have a whole selection of food that we can give the pilots and they drink it through a straw that goes into that hole. They can have applesauce, beef stew, key lime pie, peaches, chocolate pudding, you name it!” Joey was excited to share the menu with me and I couldn’t help thinking that the key lime pie sounded pretty good. And after actually trying it, I can confirm it does taste exactly like key lime pie, just put through a blender.
The pilots get to choose what type of inflight food options they bring along. Squeezing the Key Lime Pie out of the tube was not very easy. Credit: NASA/Katie Stern
After answering a few other questions of mine, Joey escorted Cory out to the jet. Witnessing the amount of preparation to get ready for the flight only made me want to learn more about the ER-2 and its history. It also gave me a huge appreciation for all of the expertise that goes into ensuring the success of the IMPACTS mission and other NASA missions.
Pilots Tim Williams and Cory Bartholomew pose in front of the NASA ER-2 with Project Manager Bernie Luna and Deputy Project Manager Katie Stern. Credit: NASA
After visiting with part of the SnowEx 2020 airborne team, we headed up the mountain to rendezvous with the ground team, stationed at Grand Mesa Lodge.
“Does anyone have a headache?” asked Jerry Newlin, SnowEx operations manager, as we left the little town of Delta and the rugged brown foot of the mountain range loomed up in front of us.
“Nope, feeling great” was our answer at the time. We traveled up the winding roads, commenting on the views that became more incredible the higher we went, and arrived at Grand Mesa Lodge in time for dinner and the evening briefing with the team.
But later that evening, at 10,500 feet, both video producer Ryan Fitzgibbons and I started developing symptoms of altitude sickness. Lower oxygen levels at higher elevations can cause headaches, nausea, shortness of breath, dizziness and other symptoms as the body adjusts. Sometimes the symptoms resolve on their own as the body gets used to the conditions; after a long, rough night of intense headaches and nausea, I gratefully accepted an herbal medication from the Grand Mesa Lodge owners. (Severe cases of altitude sickness require quickly moving back down to lower elevations. The ops team kept a close eye on me to make sure I didn’t need medical attention.)
After I took a nap back at my cabin and started to feel better, we checked in with Jerry and were cleared to snowmobile up to the snow pits.
The ground team’s daily “commute” varies depending on where they’re working that day, but it can be as much as 16 miles of hills, curves, bouncy stretches and incredible views of the valley below.
The SnowEx team reached the field sites via daily snowmobile trips. The ride is bumpy and can take 45 minutes to 2 hours, depending on where they’re working on the mesa. They towed their instruments and gear on sleds behind the snowmobiles. Credit: NASA / Jessica Merzdorf
At each of the snow pits in this 3-week phase, the SnowEx ground team digs until they reach the ground, exposing a “wall” of snow where they take their measurements: Depth, density, water content, temperature, reflectance and particle size.
“We can see, and even hear, how the snow’s characteristics change from top to bottom,” said Chris Hiemstra, a researcher with the U.S. Army Corps of Engineers’ Cold Regions Research and Engineering Laboratory (CRREL). “The newest snow at the top is fluffy and loose. Below that, the wind has packed it into dense layers. The snow at the bottom has more water and the particles are sharper. When you dig into it, it sounds different than the other layers at the top.”
When we stopped by deputy project scientist Carrie Vuyovich’s pit, we heard the story of the “strong work mouse,” and saw a snow statue (made from wind-packed snow, incidentally) built in the mouse’s honor.
The SnowEx “mascot” for 2020 was the “strong work mouse,” honoring the small field mice that visited the snow pits during the first two weeks of data collection. Suzanne Craig of the National Snow and Ice Data Center records data next to a snow sculpture of the strong work mouse. Credit: NASA / Jessica Merzdorf
“There were these little mice that came to visit us in the first couple of weeks,” she said. “We’d be in pits, and these little mice would come running across the snow – one came down into the pit and hung out with us for a while, another team had a mouse running along beside them, and another member had a mouse come right up next to his boot. So that became our mascot – the ‘strong work mouse.’”
Not all of the research takes place in pits. Team members on skis used snow micro-penetrometers (SMP’s) to measure hardness and microstructure throughout the snow layers with incredibly high precision: The SMP takes 250 measurements every millimeter. Other snowshoe-wearing scientists used MagnaProbes, which have a magnetic probe that goes into the snow and a “basket” that rests on top. The distance between the two parts provides a highly accurate, GPS-tagged measurement of snow depth, and is many times faster than writing depth measurements in a notebook.
SnowEx 2020 project scientist Hans-Peter (HP) Marshall drives his snowmobile in a tight clockwise circle called a “radar Hiemstra spiral”, taking active radar measurements of the snow. The Twin Otter aircraft carrying SWESARR will later fly over this circle and take similar measurements. Credit: NASA / Jessica Merzdorf
SnowEx project scientist Hans-Peter (HP) Marshall and Mike Durand, an associate professor at Ohio State University, used snowmobiles to create tight clockwise circles of radar measurements. This spiral sampling strategy is called a “Hiemstra spiral” after Chris Hiemstra, who developed them using the MagnaProbe, Marshall said. His snowmobile carried an active radar instrument, which generates pulses that bounce off the snow and the layers. These pulses are timed to nanosecond accuracy, allowing estimates of snow depth, water equivalent and thickness of major layers, 100 times per second. Durand’s had a passive instrument that measured the radiation naturally generated by earth and scattered by snow.
If these measurements sound familiar, that’s because they’re the same types, frequencies, and polarizations as the airborne instrument SWESARR, Marshall said. The Twin Otter aircraft flies over these spirals and takes the same measurements in the same location. Later, the two teams can compare the data and see how well they align with each other and the standard snow pit and depth observations. Data from both the active radar and passive microwave sensors on SWESARR will be combined to estimate snow properties such as snow water equivalent.
On the last day of data collection, Vuyovich revealed that the team had successfully collected data from 153 snow pits and 6 SWESARR flights in just three weeks — even more than originally planned.
SnowEx 2020 operations manager Jerry Newlin (ATA Aerospace) caught Chris Hiemstra (U.S. Army Corps of Engineers’ Cold Regions Research and Engineering Laboratory) in the reflection of his goggles during one of their daily snowmobile commutes. “It looks like Chris is collecting data on the Moon,” Newlin said. Credit: NASA / Jerry Newlin
But SnowEx is off to a great start, not wrapping up. SnowEx 2020 has another phase: The time series. Smaller, local ground teams are currently performing weekly snow measurements at sites in Colorado, Utah, Idaho, New Mexico and California through March, and bi-weekly in April and May, at the same time as UAVSAR overflights. UAVSAR is an L-band InSAR (radar) instrument developed by NASA’s Jet Propulsion Laboratory. The time series will give the researchers data on how snow changes over time, especially as it melts in the spring.
When asked about the best memories they will take home from the mesa, each team member’s answer was the same: The team.
“The best part has been the team,” Vuyovich said. “The people that have been out here have been working super hard, and it’s been a lot of fun.”
“These kinds of intensive field campaigns form bonds that last a career,” said Marshall. “Chris Hiemstra and I met during the last big series of field experiments 17 years ago, and we have been working together ever since. The younger generation in particular really stepped up this campaign – it will be exciting to see where their careers take them.”
