The third time’s the charm. Against a calm and crisp dark night sky on Florida’s Cape Canaveral on February 8, 2024, just after 1:30 a.m., the Plankton, Aerosol, Cloud, Ocean Ecosystem (PACE) spacecraft rocketed to orbit carrying on board Hyper-Angular Rainbow Polarimeter (HARP2)–UMBC’s wide-angle imaging polarimeter. The launch marked the first time NASA deployed a university payload on a large operational Earth science space mission.
Written by: Anne Wainscott-Sargent
Following two scrubbed night launches the two previous nights due to strong winds, Thursday’s successful takeoff was well worth the wait for the core team of UMBC Earth and Space Institute researchers, graduate students, and their families and friends who journeyed from Baltimore to watch the historic launch.
Photo credit: Margo Young
Arriving by bus a little before midnight to the Banana Creek Launch Viewing Area at Kennedy Space Center, just over six miles from Space Launch Complex-40, the close-knit UMBC entourage huddled together waiting for the final countdown.
When it came, they—along with hundreds of other space launch watchers—held their breath and then yelled and clapped as SpaceX’s Falcon 9 rocket blasted off and propelled PACE 400 miles above Earth into sun-synchronous orbit. Minutes later the Falcon 9’s first stage—SpaceX’s reusable rocket booster—successfully landed at Landing Zone 1. The crowd gasped audibly at the sonic boom, caused when the spacecraft broke the sound barrier.
“It still doesn’t quite feel real,” said Noah Christian Sienkiewicz, a calibration scientist who earned his master’s degree in atmospheric physics from UMBC in 2019 and expects to complete his physics doctorate this summer. “I grew up watching Carl Sagan and dreamed of going into astrophysics. I never thought I’d be the person making the instruments that will go up and do the measurements.”
“It’s so exciting—I’m going to cry,” uttered Margo Young from the upper bleacher. “I don’t always see the pieces and parts put together, so this is really historic.”
Young serves as UMBC’s HARP program administrator, where she has overseen procurement and other back-end support for HARP since the program’s inception in 2013. “I get to see students come full circle—working in the lab and then graduating and becoming civil servants where they continue to be involved because it’s such an amazing project,” she explained.
On the path to PACE
The UMBC HARP team’s remarkable journey from idea to mission reality spanned over 15 years, and involved countless hours of design, modeling, testing, and validation. Earlier iterations of HARP flew first on private aircraft over the Maryland countryside and then an award-winning “cubesat” version launched into orbit from the International Space Station (ISS), all stepping stones on the path to PACE.
For the three multidisciplinary HARP2 physics, optics, and research engineering leads, Vanderlei Martins, Roberto Borda, and Dominik Cieslak, HARP2’s launch represents a career-defining moment that at times seemed against all odds for a mid-size public university. UMBC’s strong partnerships with NASA, such as the Goddard Earth Science Technology and Research (GESTAR) Center II that supports Borda’s and Cieslak’s roles, help enable milestones like this.
“I feel like I’m still dreaming,” said a visibly emotional Cieslak, research engineer, who captured the launch on his long-range camera. Transfixed by the sight of live satellite footage of the PACE spacecraft heading to orbit, he added, “This is the last time we will physically see it [HARP2],” before hugging his long-time colleague, Borda.
“We’re very proud to have UMBC in space,” added Martins, professor of physics, who watched the big moment from a VIP viewing area three miles from the launch site. “We dreamed big from the beginning. The team persevered and just kept going.”
Always more to do
“I never despaired of having HARP2 on the PACE satellite,” admitted UMBC’s HARP2 manager, Lorraine Remer, research professor in the Joint Center for Earth Systems Technology. Her bigger worry wasn’t HARP2’s viability, but whether PACE would ever launch. “PACE was canceled four times and reinstated four times,” she recalled, noting that the program “survived a lengthy government shutdown and a global pandemic that destroyed our supply chains.”
Immediately after launch, Remer had to return to Maryland and the Goddard Space Flight Center to oversee HARP2 being turned on within 36 hours of launch. “It would be nice to bask in the successful launch, but I haven’t had much time to contemplate the success. There is just more work to do all the time,” she said.
Remer and the rest of the team would soon be relieved to learn that HARP2 had successfully begun its operations and was transmitting data back to Earth as designed. The first data, known as “first light,” from HARP2 and the other instruments on PACE arrived as planned, and NASA released the first wave of data on April 11. All of the data from PACE will be free to access and completely public, allowing anyone to conduct their own analyses and contribute to our understanding of Earth’s complex systems.
An international effort
NASA’s PACE mission clears the path for revolutionary new measurements of Earth’s oceans and atmosphere. HARP2 measures aerosol particles and clouds, as well as properties of land and water surfaces. By analyzing particles like dust, wildfire smoke, or urban pollution, the science community gains deeper insights into air quality as well as global warming and its impacts. Scientists will be able see through things like sun glint to ascertain patterns never before possible.
A second polarimeter on PACE, the Spectro-polarimeter for Planetary Exploration (SPEXone), developed through a Dutch consortium consisting of SRON Netherlands Institute for Space Research and Airbus Defence and Space Netherlands, will measure sunlight reflected from Earth’s atmosphere, land surface and ocean.
“There are undergraduate students and Ph.D.s integrated into the team who put in a lot of effort to make this real. We’re really thankful for the environment at this university—we’re able to work with students who find a career in this industry and field of research.
These two companion polarimeter instruments are important because the interaction between aerosols and clouds is the biggest unknown factor in atmospheric temperature change, according to reports from the U.N.’s Intergovernmental Panel on Climate Change.
“I have watched Dr. Martins and his team work toward this moment for about a decade, and have been aware of the trials and tribulations along the way. Seeing the smiles on their faces in the control station after the launch made it all worthwhile,” shared UMBC Vice President for Research Karl V. Steiner. “The HARP2 mission as an integral part of PACE is making all of us proud here on the UMBC campus. We cannot wait to see the science that will come from this engineering masterpiece conceptualized and created right here in Maryland.”
Waiting game
In the days leading up to the PACE launch, the HARP2 team knew there might be delays because of the weather so they rented a large Airbnb in neighboring Cocoa Beach for the full week. Earlier in the week, over grilled food at the shared house, the team reflected on their journey.
According to Martins, a key strategy was bringing together engineering and physics students, who typically don’t communicate well across disciplines.
“We introduced engineering students to the physics students and made them work together very quickly so they spoke the same language,” he said, crediting this multidisciplinary collaboration to the team’s ability to rapidly iterate and problem solve.
Borda, senior research engineer overseeing HARP2’s optical design, said a key technical challenge was determining how to best compensate for the effects of polarized light waves inside the instrument.
“It’s continuous work and you cannot do it alone. We needed a fantastic team with not only the staff but also students working at different levels,” Borda said. “There are undergraduate students and Ph.D.s integrated into the team who put in a lot of effort to make this real. We’re really thankful for the environment at this university—we’re able to work with students who find a career in this industry and field of research.”
Nurturing future career scientists
Martins echoed Borda’s pride in the broad level of participation in the HARP program, from high school students to senior scientists. “We’ve had people from our team who now work in all levels of industry—at NASA, at NOAA, or in private industry. We’ve even had some students start their own company.”
Young, the program administrator, estimates that the cooperative agreements between UMBC and NASA have resulted in 20 UMBC graduates finding roles with NASA.
UMBC alumna Elissa Ogburn is one such graduate. She began working on HARP2 as a computer science major, tasked with creating a database that supported ground communications so researchers could communicate with the instrument when it was in space.
After graduating from UMBC in 2021, Ogburn joined NASA on the PACE project as a test conductor—responsible for integrating and testing the instruments onto the PACE spacecraft. During launch, she was one of five test conductors in the PACE Control Room in Titusville, Florida, who powered up the spacecraft for the last time and configured it for launch.
“I never imagined having a job at NASA or working with people who were this smart, helpful, and kind. Every single person I’ve worked with was so fun. It’s also cool to have seen the whole process beginning as a student at UMBC. PACE is my first mission, so I’m learning everything as I go,” Ogburn said.
Close collaboration
The partnership between NASA and UMBC goes back over two decades. NASA Goddard Space Flight Center and UMBC are located just up the road from one another.
Jeremy Werdell, PACE project scientist at Goddard, recalled how initial calls to industry and academia for a polarimetry instrument for PACE were not promising due to cost and other factors.
However, Martins immediately suggested to Werdell that his lab develop a polarimeter, given his team’s experience with airborne instruments and the HARP cubesat, and the rest is history. In the end, NASA selected two polarimeters—HARP2 and SPEXone. Each instrument measures polarization differently: HARP2 is multispectral (measuring only four wavelengths of light) and hyperangular, so it looks at the same piece of real estate multiple times from dozens of different viewing directions. Its wide swath coverage means HARP2 will cover the globe every two days. SPEXone, on the other hand, is hyperspectral (measuring a continuous spectrum of light from the ultraviolet to near-infrared) but only views Earth at five angles. It has a narrower swath, meaning it will take almost a month to cover the globe.
“They’re small and mighty and miraculously complement each other very, very well,” said Werdell. “Having multi-band, multi-angle polarimetry is going to open up a lot of really interesting opportunities for discovery, because we can see clouds and aerosols in very different ways.” HARP2 provides daily views that will help scientists understand how aerosols and clouds interact and their role in warming and cooling in the atmosphere.
“Understanding where aerosols are, how they’re transported, how they interact with clouds, and whether they absorb or reflect radiation is important to everybody because those characteristics are what drive warming of the atmosphere.” Werdell said.
Better air quality models
Onsite at the Cape for the first launch attempts, Nirandi Jayasinghe and Rachel Smith, both physics graduate research assistants at UMBC, shared their excitement for the PACE mission and HARP2’s potential to help modelers predict air quality, rain, or if the atmosphere is warming or cooling.
Jayasinghe is a data modeler who comes up with different methods to retrieve information from HARP2. Originally from Sri Lanka, Jayasinghe notes that her hometown used to be one of her country’s cleanest cities, and now due to development in Sri Lanka’s dominant neighbor, India, the air quality is extremely bad. She said HARP2 can help close the gap that exists in understanding the twilight zone—where a cloud starts and where it stops—by providing more accurate measurements.
“No other place would have let me be involved in the entire process…. Not only did I get to do hands-on stuff, but I also was part of the design and saw it all come together on a NASA mission.
Smith adds that this will go a long way in understanding cloud formation processes, weather patterns, forecasting, and climate modeling—information important for agriculture, transportation, disaster preparedness, and infrastructure planning.
“Even simple things like weather forecasting are impacted by how much dust is in the air,” said Smith, a 2026 doctoral candidate who earned her M.S. in atmospheric physics from UMBC in 2023. HARP2 will help address whether clouds have a net cooling effect or a net warming effect, which will allow for more accurate models of where Earth’s climate is headed. Smith notes that during events like the Canadian wildfires in 2023 no one could accurately predict rainfall, because the forecasting models were not accounting for the number of airborne aerosols.
“I’m really excited to see what new science questions come out of the instruments that we’re putting up in space,” she concluded.
Bouncing back from disaster
The first images from PACE’s HARP2 polarimeter captured data on clouds over the west coast of South America on March 11, 2024. The view of polarized light that the polarimeter “sees” (on the right) can help scientists better understand the droplets that make up the cloudbow—a rainbow produced by sunlight reflected from cloud droplets instead of rain droplets—which can reveal how the clouds respond to pollution and other particles in the atmosphere. Photo Credit: UMBC
The HARP2 team has come a long way from initial concept to PACE. What impresses Werdell the most is the UMBC team’s resilience in the face of setbacks.
The most devastating moment came in February 2022, one month before the team was set to deliver HARP2 to NASA for integration on the spacecraft. As the instrument was in the last few seconds of vibration tests, the bonding on one of the prisms loosened and shattered.
“It tactically put us to point zero,” recalled Cieslak, who was shocked and humbled when so many NASA scientists volunteered their time and expertise to help the HARP2 team get back on track. “We got an extension, and within two months we had built a new engineering model and were able to prove the new solution worked. By September, we were back to where we were before the incident,” he added.
First-time NASA launch attendee Yomiyu Fekadu ’20, mechanical engineering, M.S. ’23, engineering management, recalled that time well, as he helped assemble HARP2 as an intern under Benjamin Cramer ’17, M.S. ’20, mechanical engineer on the program.
“Especially after the failure, and the review board assessment, I helped put everything back together and do the test plans for construction and other documentation so NASA could give us the go-ahead to move on,” Fekadu said.
The experience was pivotal to his career. “It was everything I could have asked for,” said Fekado, now a systems engineer at Northrop Grumman. “No other place would have let me be involved in the entire process, including making parts for HARP2 in the machine shop. Not only did I get to do hands-on stuff, but I also was part of the design and saw it all come together on a NASA mission.”
As the HARP2 group left the viewing platform to line up for bus rides back to the Space Center, the smiles and easy camaraderie conveyed a collective sense of pride, relief, and excitement.
“I‘m now just anxious to see the first bytes of data,” said Cieslak, echoing the feeling of his colleagues.
In addition to the HARP team, several additional UMBC GESTAR II scientists and engineers were instrumental in their contributions to the overall PACE mission, including Ivona Cetinić, Andrew Sayer, Violeta Sanjuan Calzado, Bridget Seegers, Susanne Craig, Dirk Aurin, Meng Gao, and Ian Carroll.
