Have you ever been curious about what in the universe the nearly 5,000 satellites orbiting Earth are doing? Well, for starters, only about 2,787 of them are active – talk about a lot of space junk. Each satellite sent into orbit has a different purpose. Some are for communications and others are for earth observations and scientific research to help us understand climate change. 

Circling the earth is a squad of European satellites, working together and collaborating with other satellites to understand the changes on our planet caused by climate change. These little heroes are called the Sentinel satellites. There are currently 8 Sentinels in orbit, with several more scheduled in the coming years. Together, the Sentinels, which are part of the EU’s Copernicus Programme, can help us plan for a better future by preparing for and understanding the changing earth systems. 

ESA Clean room event sentinel 6

Late last year, the European Space Agency (ESA) invited me to meet Sentinel 6A in person. I got to suit up and head into the cleanroom to meet 6A before it would begin final tests and journey to California for a launch on a Falcon 9. I also got to chat with some of the folks behind the project, learn more about the collaborative efforts, and learn how the satellites benefit European citizens and global populations. So, let’s take a look at this fantastic posse of satellites working around the clock, or rather around the earth, to help us combat climate change.


The EU developed the Copernicus Programme to help governments, scientists, NGOs, businesses, and corporations access free public data to help them adapt and mitigate environmental changes. 

Copernicus uses Sentinel satellites, airborne data, and ground stations to compile information targeting six areas:

  • Climate Change
  • Emergency Management
  • Land Monitoring 
  • Atmosphere Monitoring
  • Marine Environment Monitoring
  • Security

The EU approved program started in 2010, and the first satellite, Sentinel 1, was launched in 2014. There are missions planned well beyond 2030, which means the EU and the world can utilize the data for short and long-term monitoring. Access to this data today and well into the future will help governments and communities prepare for and predict what changes lay ahead for the earth.

Each satellite in the series has a unique payload (or observation tools) optimized to collect data and monitor specific things, such as rising sea levels, ice density, air quality, and more. Most satellites will only last for about 5-7 years, but most have a twin satellite to extend their lifespan. The twins are launched later and continue collecting and enhancing the same data as its twin. So, for example, there will be a Sentinel 6A and 6B.

Up Close with Sentinel 6

Before my introduction to 6A, I first had to cover my clothing, hair, and shoes and turn off my phone. Any stray hair or phone signal could have tainted the entire satellite resulting in more tests. I must have checked my phone and tucked my hair behind my cap a dozen times, just to make sure. No one wants to be THAT person. 

I was surprised at how small and compact the satellite was, which makes sense considering the need for efficiency, but it was still a bit mind-blowing to be in the same room as a satellite. One of Sentinel 6’s unique features is its trapezoid shape and “roof” of solar panels. This fully mounted solar range means Six can capture the sun from all sides, enabling a stable orientation without turning toward the sun for power. Most satellites have to turn their solar panels to face the sun, making them less efficient.

Sentinel 6 – ‘Surfing the Seas’

ESA Clean room event sentinel 6

ESA Profile: Before being hired as a satellite, 6 was often found at the beach. Many neighbors would whisper during Monday night bridge that 6 was just a beach bum, surfing the waves from dawn until dark. Over time, 6 noticed that the coastline along their favorite beach was changing. Sea levels were rising, temperatures were increasing, and more sea life was washing ashore. In a valiant effort to understand the rising sea levels threatening their home, 6 was hired to be the latest in the line of superhero satellites. 6 is looking forward to providing data on the changing ocean to protect coastal communities around the world.

Mission Stats

Climate Change. Atmosphere Monitoring

To monitor sea-level variability and rising sea levels by mapping 95% of the Earth’s ice-free ocean every ten days.

  • Improved forecasts of ocean currents, wind, and wave conditions
  • Clarity on how the ocean stores and redistributes heat, water, and carbon
  • Empowers communities to understand the implications of land development

ESA Clean room event sentinel 6

Short term goals: Sustainable ocean resources management of coastal communities

Long term goals: Climate forecasting


  • SAR Radar altimeter records wind speed, sea-surface and wave height.
  • GNSS-RO uses radio occlusion to create profiles of tropospheric temperature, pressure, and humidity.

Launch Date: November 2020 on a Falcon 9 from Vandenberg, AFB, USA.

Why is Monitoring Sea Level So Important? Global sea levels have been rising by an average of 3.2mm per year since 1993. However, data shows the average is increasing. Sentinel 6 maps global sea levels every ten days to help us understand long and short term projections for coastal communities. 6 will also provide valuable information on the impact of global greenhouse gases and how reducing them might help.

Disappearing Belgium: At the current rate for sea-level rise, Belgium’s coast will be submerged by 2050. This will displace thousands, create an economic disaster, causing future erosion and ecosystem degradation threatening biodiversity and food and housing security. Belgium needs to make a conscious effort to combat climate change, restore natural defenses, and plan for rising levels. Data from Sentinel 6 will help Belgium, and many other coastal countries protect their citizens.

Indigenous Arctic Communities: During the Sentinel event, I asked how Alaskan (my home state) communities might use this data. Alaska has the first climate change migrants in the United States. Many of the communities at risk are Native villages, experiencing extreme flooding and those that rely on ice for subsistence hunting. Arctic communities and Indigenous peoples across the Arctic can access the data to help plan and potentially move their villages before a disaster. The data can also help them project loss of sea ice, which will be valuable to determine any future loss of subsistence hunting.

Meet the Rest of the Team

Sentinel 1 – ‘Radar Vision’

ESA Profile: During a tragic lab accident, that has been thoroughly redacted, 1 came down with a strange case of ‘radar vision’. After being rejected by society for their creepy and off-putting stare, 1 wandered the streets gazing up through the clouds dreaming of using their strange new superpowers for good. Their dreams came true after being picked up by a large unmarked white van in a dark alleyway. Some people in suits offered 1 the chance to launch into space. There, while orbiting the earth, they use their radar vision to peer down through clouds and help scientists create detailed maps of the planet, no matter the weather. 

Sentinel satellite 1

Mission Stats

Climate Change. Marine Environmental Monitoring. Land Monitoring. Emergency Management. Security. 

This polar-orbiting satellite works day and night, come rain or shine. Utilizing advanced radar technology (SAR), Sentinel 1 creates images of the Earth’s surface even when cloudy.

  • Creates maps of forests, water and soil, and agriculture 
  • Monitors sea ice zones and the arctic environment
  • Surveys the marine environment
  • Monitors land surface motion risks

Launch Dates: 

  • 1A launched in April 2014 on Soyuz from Kourou.
  • 1B Launched April 2016 on Soyuz from Kourou.
  • Sentinel 1C & D – coming soon!


  • C-Band SAR sends advanced radar MicroWaves to the earth. When they return, it creates an image.
  • Sentinel C& D will have a SAR augmentation for marine surveillance applications.

Importance and Uses:

  • Forest mapping – helps forest service isolate and control the spread of disease and manage wildfires. 
  • Water and soil mapping – helps manage flood risk and response.
  • Oil spill tracking – helps monitor the spread enabling fast and efficient response.
  • Timely maps of sea ice – help shipping and cargo plan routes. Ships can use real-time data to monitor wind and waves for safe passage. 
  • A detailed polar map. Polar regions are typically cloudy; SAR technology can help us map these regions.
  • Urban planning for coastal communities and flood plains.
  • Monitoring and predicting volcanic activity.
  • Quick and consistent imaging helps humanitarians with crisis response.

Sentinel 2 – ‘Color Vision’

Sentinel 2

ESA Profile: While studying mantis shrimp’s unique abilities, 2 created a pair of super color glasses so humans could enjoy high-resolution color for the first time. 2 became a world-renowned artist using colors only seen by using their exclusive glasses. Surrounding themselves by elitists and the type that sells banana peel art for billions of dollars with a martini in hand, 1 began to wonder if this was too vapid a life for them. Approached by a woman in a dark suit at their latest showing, 1 was never seen in the elite art circle again. Word is they are using their color technology while orbiting earth creating images to monitor vegetation levels.

Mission Stats

Climate Change. Land Monitoring. Emergency Management. Security. 

Sentinel 2 creates high-resolution images every five days to track and monitor changes in land use and vegetation levels.

  • Monitors land cover, usage, and change due to farming, deforestation, urbanization, and natural disasters
  • Creates geophysical maps to understand details such as lear chlorophyll and water content
  • Creates images of pollution in lakes and coastal communities
  • Accurate images of volcanic eruptions and landslides for disaster mapping and aid

Launch Dates: 

  • 2A Launched June 2015 on VEGA from Kourou, French Guiana.
  • 2B Launched March 2017 on VEGA from Kourou, French Guiana.
  • Sentinel 1C & D – Coming Soon


  • A multispectral instrument (MSI) optical imager creates high-resolution images of earth.

Importance and Uses:

  • Leaf content images help monitor plant growth, vital to farmers during the growing season, and support reforestation efforts. 
  • Provides critical information to optimize crop yield, improving food security
  • Offers crisis responders with accurate information during natural disasters 
  • Land managers worldwide can use the information for early detection of fungus or pest control by identifying problem areas.

Sentinel 3  – ‘Surf and Turf’

ESA Profile: 3 was once just a humble chef at Benihanas. Their only claim to fame was creating the lip-smacking surf and turf combination found on every menu around the United States. 3 always knew there was a special connection between land and sea. 3’s private notes detailing their hypothesis were found by the Benihanas CEO, who had a distant relative at the ESA. 3 was last seen taking their 20-minute break outside the restaurant and is likely orbiting space to monitor the changes to both land and sea. 

Sentinel 3

Mission Stats

Climate Change. Marine Environment Monitoring. Land Monitoring. Atmosphere Monitoring. Emergency Management.

The twin satellites provide two-day global coverage monitoring ocean and land.

  • Colorful sea and land data, including temperature
  • Colorful topographic measurements of ice, lake, and river water
  • Monitors the quality and pollutants levels of seawater

Launch Dates: 

  • 3A launched Feb 2016 on Rockot from Plesetsk, Russia.
  • 3B Launched April 2018 on Rockot from Plesetsk, Russia.


  • Ocean and Land Color Instrument
  • Sea and Land Surface Temperature Radiometer  

Importance and Uses:

  • Improves ocean forecasting for maritime safety
  • Enhanced predictions for storm surges and flooding
  • Early forest-fire detection for better response and crisis management

Sentinel 4 – ‘EU Air Defender’

Sentinel 4

ESA Profile: 4 wasn’t like the other Europeans who always had a cigarette in one hand and a stack of papers ready to roll in the back pocket. Suffering from chronic asthma, 4 often stood on the sidewalk with a cardboard sign advocating for better air quality. All 4 wanted was the right to clean air. After working their way through the EU bureaucratic command, they were given the opportunity to launch into space to monitor European air quality. Finally, 4 can fight for safe, clean air for all Europeans – even if they refuse to quit smoking. 

Mission Stats

Climate Change. Marine Environment Monitoring. 

 Sentinel 4 provides data hourly while monitoring European air quality from a geostationary orbit.

  • Monitors trace elements of Nitrogen Dioxide, Formaldehyde, and Aerosol in high spatial resolution for better forecasting and air quality monitoring
  • Provides information on ozone and solar radiation for better UV forecasting and climate monitoring
  • Enhance the monitoring of the North African Sahara
  • Complements Sentinel-5

Launch Dates: 

  • Planned launches in 2023 (A) and 2030 (B)
  • 4A and 4B launch with Meteosat Third Generation Sounder satellites.


  • Main Optical Unit contains optical and detection chains.

Importance and Uses:

  • The data allows the EU to make science-based climate policy and legislation to improve air quality throughout Europe. 

Sentinel 5 and 5p – ‘Global Air Defenders’

ESA Profile: 5 and 5P were twins separated at birth. After meeting at a science summer camp, in a story that was surely ripped off from Parent Trap, the twins bonded over their poor health due to particulate matter in their home countries. The twins put their heads together and won scholarships and awards for their fight for clean air. Not long after, they were picked up from a science fair in a suspiciously familiar white van. They now monitor global air quality in hopes that children won’t grow up with chronic illness.

Sentinel 5

Mission Stats

Climate Change. Atmosphere Monitoring. 

5 provides continuous monitoring of air quality worldwide at a high resolution and from a low orbit. 5P is a simplified precursor to Sentinel 5, providing air-quality measurements until 5 is ready for launch. There are six planned satellites in the 5 series. 

  • Provides long-term global measurements and projections on atmospheric variables
  • Monitors greenhouse gasses 
  • Tracks how atmospheric air pollutants move through the atmosphere

Launch Dates: 

  • 5P launched Oct 2017 from Plesetsk, Russia.
  • Planned launches in 2021 (A) and 2022 (B)
  • Additional launches planned for 2028


  • Includes five different spectrometers to test for greenhouse gasses, aerosols, and reactive gasses.  

Importance and Uses:

  • Provides global policymakers with a better understanding of air quality for better policy to tackle climate change. 

Do you remember when China first went into lockdown in 2020 after the outbreak of COVID-19? News outlets were reporting about the sudden and real-time improvement of air quality. That data was collected from 5P!

The Future Sentinels

The ESA just released more details about Sentinel 7. It will continue the mission of monitoring air-quality with a specific focus on CO2. CO2 mapping will help determine if countries meet their Paris Agreement goals regarding air quality, greenhouse gas emissions, and more. The satellite’s construction will begin soon, and hopefully, we can expect a launch date in 2025. 

There may be no end in sight to the Copernicus Programme. There are rumors that a Sentinel 8 will have a thermal infrared sensor to help us better understand volcanic activity, forest fires, and drought. Sentinel 9 is rumored to focus on polar ice, including thickness, and provide better weather imaging.

Real Ways the Satellites Help

Free Data for Everyone!

All data collected by the Copernicus program is free and available for anyone to access. Ensuring the data is open and accessible has allowed governing bodies, conservation groups, land managers, farmers, and citizens to plan for a changing climate and earth-based on scientific data. The data has helped manage the spread of disease in forests, track deadly algae blooms, monitor glacier recession, respond to emergencies, develop climate apps, and protecting cultural heritage sites. Let’s take a look at some of the real success stories. 

Emergency Relief to Latvian Farmers

The sentinel data can be beneficial for long-term monitoring. But the accurate and real-time data allows for fast and instant relief during a climate emergency, such as in Latvia. In 2017, unexpected flooding due to climate change, devastated Latvia’s farmland, resulting in a state of emergency. Latvian farmers needed immediate financial relief due to yield loss. The government struggled to distribute funds as most of the survey roads were inaccessible, due to the floods. Overlapping optical data from Sentinel 1 & 2 mapped the flood zone every few days. This data saved the Latvian government time and money, and 3,100 Latvian farmers received compensation for loss of yields within two months. Previously the Latvian government would have waited to distribute funds after clearing the roads, causing financial insecurity.   

Glacial Monitoring in Iceland

Iceland contains most of Europe’s glaciers. Monitoring these glaciers is critical to global sea levels. The rivers flowing from the glaciers fluctuate annually and are subject to large-scale outbursts of water flow due to the region’s volcanic activity. Floods block roads putting tourists and locals at risk. 80% of Iceland’s energy is renewable from hydropower. Understanding the changes in glacial rivers is vital to securing the future of renewable power in Iceland. It is far too expensive and complicated for such a small population to use traditional means (airplane surveys) to map glaciers. Sentinel 2A mapped ⅔ of Iceland in 2017, and its frequent updates help locals respond to road flooding, energy use and keeps tourists safe while visiting glaciers. 

If you’re interested in accessing this free data, you can follow these easy steps provided by GIS Geography to look at the Copernicus Data. You can also reach out to the Research and User Support team. 

A Collaborative Effort

The European Space Agency is not working alone on these missions. At the Sentinel 6 event, Sandra Cauffman, the inspiring woman directing NASA’s Earth Science division, discussed NASA’s involvement. Many of the missions will continue or lend data to NASA satellites in space. NASA contributed a GNSS-RO to Sentinel-6, the payload that creates tropospheric temperature, pressure, and humidity profiles, hinting at future collaborations with NASA and the ESA. 

Several women are involved in the Copernicus Programme. Being a woman at the 6A press event and seeing Sandra Cauffman, NASA’s Earth Science Director, Astrid Christina Koch, the head of the European Commissions Copernicus Programme, and Simonetta Cheri, the head of strategy programs for Copernicus, was inspiring. After chatting with the women, they made it clear that there is space for women at the ESA and Copernicus Programme, and it is exciting to see what the future holds for women in space.  

ESA Clean room event sentinel 6

Also present at the Sentinel 6 event were Airbus, IABG, CMEMS, LEGOS, and EUMETSAT, highlighting how many people come together from around the world to ensure the global population has access to free climate data and resources to help plan and prepare for future climate change. 

Discuss, Share, Engage


  • Has your country used Sentinel data to help in a climate-related crisis? You can read some inspiring case studies from Africa to Iceland to see how this free data helps people worldwide! Let me know in the comments if you’re country has used this data.
  • Which satellite do you think is the most important for helping us understand climate change? Why?
  • If your country hasn’t used the data, let me know in the comments some areas they might be able to use this information.
    • You can even write a local politician and let them know about the free data provided by the Sentinel satellites.


I hope you enjoyed reading about this amazing team of satellites helping us combat climate change. The Sentinel Satellites and the Copernicus Programme give us a fighting chance to adapt to our planet’s changing climate. Make sure you share this, so your friends and family can learn all about the Sentinel Satellies.