A NASA engineer at our Zagreb office

Thursday, Aug 11, 2022 - Posted by Mirta Medanic
A NASA engineer at the Zagreb office

Imagine a NASA engineer coming to visit. Imagine all the things you can learn!

This happened recently at our Zagreb Office, when Zoran Kahrić, a Space Engineer at NASA, a Chief Engineer at the ICESat-2 mission - and a dear colleague of ours - paid us a visit to share news on development activities at the NASA's Goddard Space Flight Center.

Zoran has been working at NASA for over 20 years. He is involved in the development of Earth Observation (EO) sensors in missions such as PACE, ICESat-2 and CASALS. This lecture was highly interesting to our employees, especially those who are working on Blink, our wideband pure-software modem for Earth Observation.

We mentioned this lecture in our monthly blog, with a promise to give some more information on the topic. So here we go!

How does NASA observe the Earth?

Zoran explained to us the three techniques that are used in different NASA missions.

view of the adriatic sea from above
Ocean Color Image of the Adriatic Sea, credits: NASA, Landsat 8 on Dec 14, 2020

Monitoring the color of the sea to protect marine life and ecosystems 

Once sunlight hits the ocean surface, a part of it is reflected and a part is absorbed. The amount of reflected sunlight is collected by the sensor on board the spacecraft. The end result is an ocean color map from which oceanographers and marine biologists can determine the composition of the sea, the type of phytoplankton that lives there and its amount. This data can for example help to measure the ocean health as well as to predict the fish stock in the area.

This technique is used in the PACE mission (Plankton, Aerosol, Cloud, ocean Ecosystem), NASA's most advanced global ocean color and aerosol mission to date. A primary sensor used in this mission is the Ocean Color Instrument (OCI), a highly advanced optical spectrometer. At this moment, the mission is in the development phase and is scheduled to launch in 2024.

ice shield measuring
Illustration of NASA’s ICESat-2, credits: NASA

Measuring the level of the arctic ice shield to monitor climate change

Bright green laser light is beamed from the spacecraft towards the Earth from a 500 km orbit. The signal bounces off the ground and travels back into space. The response signal is detected by the sensor onboard the spacecraft. From the time difference between the two signals the distance between the Earth surface and the satellite is calculated. Scientists use this information to monitor ice thickness and the volume of melted ice in the scope of climate change studies.

This technique is used in the ICESat-2 mission (NASA Ice, Cloud, and land Elevation Satellite-2). The satellite carries ATLAS, the Advanced Topographic Laser Altimeter System. The ICESat-2 satellite is currently on-orbit producing a terabyte of data daily.

light banding angles
Dispersion of a white light in the optical prism, credits: NASA

Scanning the Earth without moving parts for mission improvement

When white light projects into a prism it splits into multiple color bands with different frequencies that continue to travel in their own directions. These rays can be used for scanning the Earth and environment. Using this type of a remote sensing technique, multiple measurements can be taken concurrently without moving the remote sensing instrument.

This technique is used in the CASALS mission (Concurrent Artificially-intelligent Spectrometry and Adaptive Lidar System), a successor of ICESat-2. The mission aim is to support scientific studies of the carbon cycle and ecosystems, cryosphere response to climate change, natural hazards and atmospheric clouds and aerosols. CASALS is a demonstration mission. It will fly on a high-altitude, sub-orbital balloon. Technologies that will be used are adaptive lidar, hyperspectral imaging and on-board artificial intelligence (AI).

Contact us if you are interested in learning more about this topic. Or would you like to join us and lend a hand with our satellite projects? Apply for the open positions at Amphinicy in Zagreb or Luxembourg.