Flocks of CubeSats can efficiently monitor farms

The widespread use of low Earth orbit (LEO), especially by thousands of CubeSats, has opened up many opportunities in research and business applications. One particular field that has benefited from the data that CubeSats provide is farming.

Precision agriculture (PA) is a technique that uses advanced sensors, including the remote ones on CubeSats, to determine the health and productivity of a farm. A recent review paper published in Computers and Electronics in Agriculture from Lamia Rahali and her co-authors at the Mediterranea University of Reggio Calabria’s Department of Agriculture looks at how CubeSats have been changing the practice of precision agriculture—and how they may continue to do so.

CubeSats are great remote sensing platforms. They can carry a platform of sensors in a wide range of wavelengths, most of which can provide some direct insight into a farm’s physical properties. This process started in 2003, with basic vegetation modeling at a very low level of spatial resolution and even less temporal resolution—in other words, the pictures of fields were grainy, and they weren’t taken very often.

That state improved gradually over the years, but a significant leap forward happened in 2013 when Planet Labs, a company founded by former NASA engineers, launched its first 3U CubeSat with the intent of providing Earth monitoring data. Luckily for farmers, that data can also be used to analyze their crops.

To do so, they must interface with the Planet Labs graphical user interface (GUI) or application programming interface (API). One crucial advantage Planet Labs has over other companies offering Earth observation is the ease of use of their database systems—they have put significant effort into making the experience of downloading, trending, and analyzing data from their data sources much simpler, which is why researchers like Rahali and others like her are drawn to them. This is also why they are prominently featured in this more recent review paper.

Planet Labs has launched what they call PlanetScope constellations, which currently have around 130 active satellites that can cover around 200 million km² of landmass every day. Individually, the satellites are called “Doves,” and there have been several iterations of them over the last decade. They are collectively launched, primarily by SpaceX rockets but originally by release from the ISS, in large groups known as “flocks.”

These flocks offer precision agriculture researchers and users one crucial feature—near-daily picture updates. While they might not be able to take an image of a particular field in a specific wavelength every day due to cloud cover or orbital mechanics, the sheer number of images would, over time, allow users to build up a trend of how the plot is performing and whether any adjustments are needed.

Another advantage the Doves have is the spectral bandwidths they provide high-resolution images. Generally, they provide a resolution of about 3m per pixel and in a wide range of optical and infrared spectra, providing different data points about various aspects of plant health and growth. This data has informed research on everything from pest detection to nitrogen management, and it’s all available relatively inexpensively for farmers to use.

While this might sound like an advertisement for Planet Labs’ products, the authors claim they had no conflicts of interest regarding the company (nor does this author). The study authors point out alternative systems, such as using UAVs or the Sentinel-2 platform, which offers open-source data. However, UAVs suffer from regulatory limitations regarding their ability to fly over large areas without supervision, and Sentinel-2 lacks the space resolution to be valuable to small plot holders.

There are still some gaps in the data offerings that would be useful for precision agriculture practitioners, especially in other infrared bands. Improvements there could enable better soil moisture content, allowing them to provide irrigation at the right time. Given the importance of agriculture to the underpinnings of the world economy, improvements in its efficiency are always welcome—especially when they come from space.