People of PACE: Kirk Knobelspiesse Keeps His Eyes on the Skies

Kirk Knobelspiesse is an atmospheric scientist and the project science team polarimeter lead for PACE at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. He is also the polarimeter instrument scientist for the Atmosphere Observing System (AOS) constellation.

A man stands centered in the image standing straight with his arms held out on either side of him. He is standing on a tan sand dune. The sky behind him is a light blue and gray color.
Kirk Knobelspiesse hiking sand dunes near Swakopmund, Namibia, during the ORACLEs field campaign. Image Credit: Michal Segal-Rozenhaimer

What is your favorite atmospheric or ocean related book or movie?

There was a series on Netflix called “Connected” that had an episode called “Dust.” The general idea is that everything in the world is connected, so it started with dust that was generated in the Sahara Desert, specifically the Bodélé Depression. And that dust – which is really from a dry lakebed – gets lofted into the atmosphere and goes out over the oceans, and in the process interacts with clouds and potentially fertilizes the ocean. That dust makes it all the way to the Amazon basin where it may also be an important source of nutrients.

What is your background?

I am a photographer who got really into imaging of all kinds, which led me to remote sensing. I ended up doing work on remote sensing of Earth from space and worked on SeaWiFs, which was an early ocean color mission. I decided I need to go back to grad school and get a more quantitative education, so I got an applied math degree at Columbia University.

What are you most looking forward to during launch?

Earlier in my career I worked on a satellite that had a launch failure (Glory in 2011). So, during launch, I am going to shut myself in a closet and not learn any news until somebody tells me it’s all over. Because it makes me so nervous. A lot of people want to go and see the launch and that kind of thing. Not me, I’m going to stay away. Somebody will tell me when it’s all over.

What are you most looking forward to post-launch?

A man is sitting at a desk in an office. He is facing the camera and appears to be taking a selfie. He takes up the right side of the image. The left side of the image shows a computer screen and a water bottle, which the man is holding. In the background, the office door, a coat rack, and part of a whiteboard can be seen.
Kirk Knobelspiesse in his office at NASA’s Goddard Space Flight Center in Greenbelt, Md. Image Credit: Kirk Knobelspiesse

I have a list of all the Science and Nature papers we’re hoping to write with PACE data. It’s ambitious, a little bit. But there are new types of observations that we will be making, that no other satellite will have done so far, at least not at a global scale. One aspect I’m interested in is just exploring the data, looking for basic things that will be useful for our understanding of aerosols and clouds and the climate in general.

I have some pet projects that I’ve always been interested in, for example a specific situation when aerosols are lofted above clouds. Aerosols are generally something that cools the climate because they reflect light. But if you have, say, a dark smoke aerosol on top of the cloud, it actually warms the climate, because it absorbs some of the energy that would have otherwise been reflected into space. So that’s something we’ll be able to do with PACE that we don’t really have great observations of now.

What is your favorite color and why?

I have a 10-year-old daughter, and favorite colors are very important to her and her friends. They’re always asking me what my favorite color is, and I say I can never answer them because how can you like one color without liking all the others?

Do you have a favorite type of cloud or weird atmospheric phenomena?

There’s also an optical phenomenon called glory. If you’re floating above a cloud and the Sun is behind, you look down at your shadow and you will see your shadow with a glory around it, which is like a circular rainbow around yourself. That’s one of my favorite optical phenomena.

What’s a fun fact about yourself? Something that a lot of people might not know about you?

A man takes up the left side of the image. He is walking towards the camera. He wears a neon yellow vest and is holding onto a large, green gas canister, which is rolling behind him. In the background of the image, a large plane sits on a runway with the nose of the plane facing the left of the image and the tail of the plane, featuring a NASA logo, on the right side. The plane has a stairway connected to the door.
Kirk Knobelspiesse working on the NASA P-3 during the ORACLES field campaign in São Tomé, São Tomé and Príncipe. Image Credit: Andrzej Wasilewski

I’ve been to latitude zero, longitude zero, the point in the South Atlantic Ocean where the equator and prime meridian intersect. It was part of the ORACLES field campaign. There’s nothing special there. It’s just ocean – and I don’t mean to offend my oceanographer friends by saying it’s nothing special – but there was no pillar of fire or something like that.

What advice would you give to aspiring scientists looking to get where you are today?

Don’t pigeonhole yourself into one discipline or one topic of study. Not just computer science or physics or oceanography. They’re human constructs, sociological constructs, and they don’t have anything to do with nature, other than how we have organized ourselves. A lot of where I’ve found interesting and productive things to do have been at the boundary between disciplines, or learning from one discipline and applying that approach to another discipline. So, don’t tell yourself, “I can’t do something because I’m not trained to do that.” You can learn and you can train yourself, and don’t be afraid to go out on a limb and do something you don’t really know how to do.

What is one catch-all statement describing the importance of PACE?

We will be making use of things that people cannot see – the nature of light – to understand things that we can’t otherwise observe.

Header image caption: Kirk Knobelspiesse hiking at Rachel Carson Conservation Park in Brookeville, Md. Image Credit: Barbara Balestra 

By Erica McNamee, Science Writer at NASA’s Goddard Space Flight Center

People of PACE: Corrine Rojas Helps Connect Science to Engineering and Back

Corrine Rojas is a scientific programmer in the ocean ecology lab at NASA’s Goddard Spaceflight Center.

Before we dive into your work with PACE, what is your favorite ocean- or atmosphere-related book or movie?

I’m a big fan of ridiculous sci-fi/horror movies, and when it comes to the depths of the ocean, Sphere (1998) is one of my favorites in that genre. It’s a psychological thriller with everything you’d ever want – logistically impossible ocean research vessels, Hollywood science, aliens, spooky deep-sea fish, and even Queen Latifah! 

Corrine stands to the left of the image in a nacy blue polo and black pants. Directly behind and to the right of her is Optimism. The rover has large black wheels and it's main frame is covered in several mechanical pieces and wires. The "face" of the rover is on it's left side, still to the right of Corrine.
A picture of Corrine Rojas and the Perseverance Rover’s twin on Earth, Optimism, at NASA’s Jet Propulsion Laboratory in Southern California. Optimism is a vehicle system test bed used for safety testing of moves and navigation scenarios on Earth before performing them on Mars. (more info here: Image Credit: Corrine Rojas

What is your background? What do you do for PACE?

Before PACE, I worked on a lunar mission called Lunar Reconnaissance Orbiter, and then a couple of Mars missions including the Curiosity and Perseverance rovers. And now I’m here, back down to Earth! I’m doing science operations for Earth missions that look at ocean ecology. And there is just so much life to track here! Doing science operations, I’m a liaison between the engineering team that will control the spacecraft and the scientists that will be monitoring the atmosphere and the ocean ecology. I have to have a background in both science and engineering. I moved to Maryland from Arizona, and before PACE I was working on the Jezero Delta on Mars, near where the Perseverance rover landed. So, I’m coming in from two different deserts, and I now live much closer to the ocean flora and fauna looking at the ocean from space for a living. I feel like a little alien!


What does programming and science operations entail?

As a programmer, I’m developing tools that will tell the spacecraft where to look. Once we’re in orbit, I’ll make sure that the science team gets their priority observations. For example, if someone’s out on a research cruise collecting samples in the open sea, we can time the spacecraft to take pictures overhead which will be a really good data point for them. We’re making sure those scientists are getting what they want and packaging these spacecraft commands in a way that also works with the mission operations schedule.  

Corrine is standing centered in the image with one hand raised into the air. She is on a large plane of warped ground, cooled lava, which is a dark black and grey color. The sky above her is peeking through as blue at the horizon, but is primarily a cloudy gray color.
Corrine Rojas doing field work on Mauna Loa, Hawai’i using orbital data maps to understand the volcanic origins of the Jezero Crater floor on Mars that the Perseverance rover has been investigating. (more: Image Credit: Corrine Rojas

What advice would you give other early career scientists or other people looking to get into science operations or finding their space in… well, space?

I didn’t always see myself working at NASA. I studied political science for a few years before coming into geography and that’s my academic background – modern day geography translated into programming.

But really, what has opened the door to having this as a career, is my love for maps. Creating and reading maps has always been a passion of mine. And that passion translated to creating maps of the surface of the Moon and the geology of Mars through NASA missions. I’m grateful that NASA needs a variety of disciplines to make a mission possible.

NASA has jobs that range from computer programmers like me, to mechanical engineers and scientists, but also writers and photographers. Even finance folks. It takes a lot of different disciplines to make a NASA mission work. And if you find something that you really enjoy, there’s probably going to be a related job that can take you to working on a mission.

Corrine stands to the left of the image, wearing a white clean suit that covers her whole body including torso, arms, and head. She is seen only from the waste up in this picture and is crossing her arms across her chest. She also wears a white mask to cover her nose and mouth. To the right of her is the PACE spacecraft, which takes up a majority of the image. It is primarily a silver color and much of the spacecraft is covered in foil.
A portrait of Corrine Rojas all bunny suited-up in front of the PACE spacecraft a few weeks before it shipped to the Kennedy Space Center in Florida for launch. Image Credit: NASA’s Goddard Space Flight Center/Denny Henry

What are you most looking forward to post-launch?

That’s when my job really starts! After the spacecraft is commissioned, we’ll start commanding the sensors to take scientific observations. I’m looking forward to working with the world’s best oceanographers and atmospheric scientists, making sure that they’re getting the data they want. Hopefully we’ll have more answers regarding Earth sciences and climatology studies, especially aerosol studies since we don’t have a lot of that data. All this data will help anywhere from fisheries to disaster management and more. Everyone relying on that data is about to get a firehose of information, and I’m excited to see them dig into it.

Corrine stands centered in the image wearing pale mauve colored leggings, a white workout shirt, a green ball cap, and a brown weightlifting belt. She stands by a weight rack, directly behind the bar with her right hand resting on the black bar. She is taking this picture in a mirror using her cellphone which is in her left hand.
At the gym on center at NASA’s Goddard Space Flight Center! Image Credit: Corrine Rojas

What is a fun fact about yourself? Something that people might not know about you?

I’m a newbie, but I weightlift pretty consistently. It’s just something that I enjoy doing that takes me away from the screen and into the present moment. I can just focus on the here and now, and my body getting really strong and staying healthy.

What is one catch-all statement describing the importance of PACE?

PACE is going to help us track the heartbeat of ocean, from a few meters below the sea surface all the way up to the top of the atmosphere.

Corrine is standing centered in the image wearing a blue polo. Her hands are raised slightly up and next to her as if she is presenting something with them. Behind her is the PACE spacecraft, large, cube-like, and primarily a silver color. PACE is sitting behind a glass window separating it from where Corrine is standing.
A quick shot in front of the PACE spacecraft after volunteering for a PACE friends and family event. Image Credit: Corrine Rojas

Header image caption: Corrine Rojas during one of her many walks around Washington, D.C. during cherry blossom season. Image Credit: Corrine Rojas

Erica McNamee, Science Writer at NASA’s Goddard Space Flight Center

PACE Successfully Completes Key Environmental Test

Consider it the “mother of all tests.”

This summer, the PACE spacecraft (short for Plankton, Aerosol, Cloud, ocean Ecosystem) completed a critical phase of its launch journey: the thermal vacuum test (TVAC), where it was subjected to extreme temperatures and pressures in a specialized chamber at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

The objective? To verify the performance of the satellite once it’s launched and operational.

“This is the best way to simulate what PACE will experience in space,” said Craig Stevens, spacecraft systems lead. “Space is a vacuum, and the observatory is exposed to extreme temperatures. We must make sure PACE is ready for that environment.”

After months of round-the-clock shifts, numerous protocols, and a lot of team synergy, the mission completed its environmental testing in August, making it one step closer to launching in early January 2024.

“This proves the PACE observatory can withstand the rigorous thermal environment once it is launched and inserted into its operational environment,” said Mark Voyton, the mission project manager. “Completing the TVAC test is extremely significant, as it represents the last environmental test in our six-month environmental test campaign.”

The perspective of the image is from the top of the chamber peering down, looking into the chamber at the observatory. The inner walls of the test chamber are black, and the observatory, centered in the image and in the chamber, contrasts that darkness with copper-colored reflective material shining against the black. There are four scientists in white protective clean suits around the observatory and wires scattered on the floor connecting to the observatory and the chamber walls.
An overview of the PACE satellite entering a thermal vacuum chamber. Before the doors closed, the whole observatory was run through additional testing. Image Credit: NASA’s Goddard Space Flight Center/Denny Henry

Getting to this final test was a challenge for team members given the time and resources TVAC can take.

Before things could begin, the satellite was placed in the thermal chamber for a week earlier in June at NASA Goddard for setup.

Before the door for testing was closed, each team that had worked on PACE verified their part of the observatory was in working order, said Daniel Powers, PACE’s thermal product development lead. Members of the control room were also standing by to ensure that when the power for thermal testing went on, things worked properly. 

Once the chamber door closed, official testing lasted about 33 days.

The camera peers through parts of the observatory, focusing on an engineer who is looking intently at parts of the observatory. The engineer is wearing white protective clean gear that covers up over his head, and also includes a mask, so the only part of his face that is seen are his glasses-covered eyes. The parts of the observatory surrounding the scientist are a glimmering silver color.
Gary Davis, the missions systems engineer for PACE, examines the observatory before critical testing. Image Credit: NASA’s Goddard Space Flight Center/Denny Henry

“This is the final verification that everything is working on the spacecraft as expected. We take it to temperature extremes as well,” said Powers. “By taking it to the expected extreme environments we will see on orbit, we can see that we have everything setup and designed properly from a thermal perspective.”

The team worked three shifts – covering 24 hours each day, every day – to ensure operations ran on a strict timetable.

“You have a full marching army, and it’s all hands-on deck,” Powers said. 

A majority of the image is taken up by the observatory, primarily from the left side of the image. The complex pieces of the observatory are surrounded by wires and reflective foil-like material. Centered in the image is a red piece of equipment on the observatory, stoutly cylindrically shaped. To the right of the image stands a scientist in a full white protective suit. They stand feet slightly apart with hands resting on their hips, in a superman-like pose.
Members of the PACE team continue testing in Goddard’s TVAC chamber. Image Credit: NASA’s Goddard Space Flight Center/Denny Henry

PACE now has two more tests at ambient temperature and pressure, which complete the observatory’s post-environmental testing. Then the team begins preparing for the spacecraft’s journey to Florida and its launchpad.

Header image caption: The PACE observatory enters a thermal vacuum chamber at NASA’s Goddard Space Flight Center in Greenbelt, Md. It stayed in the chamber for 33 days of testing. Image Credit: NASA’s Goddard Space Flight Center/Denny Henry

By Sara Blumberg, NASA Oceans Communications Lead at NASA’s Goddard Space Flight Center

Six Weeks at Sea: NASA Scientists Double-Check Satellite Ocean Color Data

NASA researcher Joaquin Chaves calls it “ground truthing,” even though land is nowhere in sight.

This spring, Chaves boarded the Atlantic Meridional Transect (AMT) research cruise for six weeks of sampling water and taking measurements as the ship traversed the Atlantic Ocean. His team, based at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, uses that information gathered at sea to verify and improve ocean data from an array of Earth-observing satellites and instruments in orbit.

Upcoming satellites like the PACE, or Plankton, Aerosol, Cloud, ocean Ecosystem, mission launching in early 2024, will also use field campaigns like this one to help validate their sensors.

A scientist is crouching in front of a gray tank holding a small brown glass bottle. The scientist is wearing purple latex gloves and a green hard hat to safely perform the research aboard the ship.
Chaves is preparing to conduct scientific research while onboard. He worked around the clock to collect samples that will help check the accuracy of satellite data. Image Credit: NASA/Joaquin Chaves

These sensors start collecting data soon after launch, but it takes time to ensure that those observations are accurate and reflect what is happening back on Earth. One of the best ways to do this is to send scientists like Chaves into the field.

On the spring cruise, Chaves was joined by another NASA Goddard scientist, Harrison Smith.

“It was a lot of work, always intense,” Chaves said. “Even before you sail, you’re setting up. Every day is a work day, there are no Saturdays or Sundays.”

During their time on the cruise, the NASA team collected two types of data to build mathematical models to validate satellite data. Validation is the practice of checking the accuracy of data before it’s processed and used by NASA and its partners.

The first data type was the optical properties of water.

“Ocean color satellites measure visible light,” Chaves said. “We must try to replicate what they measure.”

A scientist is standing under a plastic sheet that serves as a barrier for his experiment station in front of him. The experiment includes several containers of liquid and plastic tubing.
Chaves conducting field experiments and validation. Credit: NASA/Joaquin Chaves

In addition to the optical measurements, the NASA scientists also gathered water samples to measure the abundance of phytoplankton pigments and various forms of carbon.

By the end of the campaign, Chaves had collected 700 samples to process, which he is now analyzing back at Goddard.

Chaves and Smith were just two of the research cruise’s passengers, which also included 25 scientists based in the UK, Europe, Africa, and Latin America. Chaves said it was one of the best field campaigns he’s been on. The researchers connected with others and talked of future collaborations.

“It’s hard work,” he said. “It remains one of my best experiences at sea because of how modern the ship was, well trained the crew were and the officers are and willing to help.”

The AMT program, which started in 1995, allows researchers from all over the world to study the ocean’s biogeochemistry, ecology, and physical properties during voyages between the United Kingdom and the South Atlantic.

Learn more about the AMT cruise here.

Header image caption: A map of where the cruise travelled for six weeks in the Atlantic Ocean. Credit: NASA/Joaquin Chaves

By Sara Blumberg, NASA Oceans Communications Lead at NASA’s Goddard Space Flight Center

NASA’s PACE Spacecraft Assembled, Advances Toward Launch

Although PACE was formally authorized in 2015, its concept has been on the minds of NASA Earth scientists for over 21 years.

In 2023, that concept is now an assembled spacecraft at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. 

This past month, the PACE (Plankton, Aerosol, Cloud, ocean Ecosystem) mission advanced closer to launch, passing a critical review demonstrating final tests for its readiness for observatory integration and testing. PACE will continue preparations for its move to NASA’s Kennedy Space Center in Florida, where it is scheduled to launch in January 2024.

“It’s an absolutely huge achievement for the team after having conceived the PACE system architecture, completed the design, implemented and built all the hardware and software systems,” said Mark Voyton, PACE’s Project Manager.

PACE’s solar array deploying in the Goddard cleanroom. Video by Denny Henry, NASA

Once in orbit, PACE will view the atmosphere and ocean surface from space. It will help scientists learn more about the relationships between phytoplankton and the surrounding environment by measuring how light reflects off the ocean and through the atmosphere.

Before any NASA mission can launch, however, it must go through a series of immersive reviews, called key decision points, to show it can operate in space. Getting to this moment has been a long time coming for the team. 

Since its inception, PACE has faced many challenges. Last year, for example, one of PACE’s polarimeters, HARP2, experienced parts failures during testing, forcing the team to reevaluate several of its design concepts. Budget-wise, the mission also experienced hurdles related to the global Covid-19 pandemic.

Testing and moving the PACE spacecraft. Image by: Denny Henry, NASA

“It is somewhat difficult to wrap my head around being fewer than 300 days from launch.  All the ideas and concepts from the past decade have been turned into reality! It’s been a long strange trip, but one we don’t regret pursuing,” said PACE lead scientist Jeremy Werdell.

PACE team members have remained busy in their preparations. Late last year, the team integrated all three of its scientific instruments onto the spacecraft, thus forming the PACE observatory. The mission most recently also completed testing the deployment of PACE’s solar array.

Next steps for the team will focus on final integration and testing activities at Goddard. This includes vibration and acoustics tests that simulate the launch environment, as well as several months of thermal vacuum tests that simulate the environment of space. 

“Once these activities are complete, the observatory will be trucked to Kennedy for additional testing and integration onto the launch vehicle,” Werdell said. 

Header image caption: PACE tech Jean Arnett is cleaning the Aronson table.  The Aronson table is used to tilt the spacecraft over like in the photo below. Image by: Denny Henry, NASA

By Sara Blumberg, NASA Oceans Communications Lead at NASA’s Goddard Space Flight Center