Aerospace for environmental protection

The Mission Aerial Firefighting

Forest fires and fires in savannah areas are increasing in frequency and severity worldwide. It is to be expected that climate change and the rise in temperature will further increase the risk of fire over the next few decades. In the future, only a quick and efficient early warning combined with the short-term availability of emergency services can help to get this risk under control.

In order to be able to react quickly and effectively to forest fires, firefighting from the air is of great importance. In addition to water bomb planes, helicopters are also increasingly being used. The mobility, speed and delivery capability of rotary wing aircrafts make them more effective than fixed wing aircrafts in the direct distribution of fire extinguishing agents. In this respect, it is to be expected that their procurement rates will increase in the coming years.

Fire alarm satellites as an early warning system

An early detection of sources of fire is an essential part of effective firefighting. State-of-the-art satellite technology is available for this purpose. Two special bispectral infrared fire alarm satellites detect high temperature events on the earth’s surface. Unlike global Earth observation satellites with relatively low accuracy, these can also be used to reduce low energy fires (e.g. burning ships, chemical heat development or smoldering fires). Whereas previous satellite systems only recorded heat sources with an output of 10 Megawatts or more, modern fire alarm satellites can detect heat events from 1 Megawatts. The use of two cameras in two spectral ranges also allows to detect fires that are significantly smaller than the scanning range. Even if a pixel is still the size of six soccer fields, fires that are about the size of a circle of impacts can be detected.

The fire alarm satellites orbit the earth at an altitude of around 500 kilometers in a polar orbit that guides the satellites over the poles. The satellites are offset from one another by half an orbit, so that one passes the zero degree of latitude from north to south at 9:30 a.m., while the other changes from the southern to the northern hemisphere at 11:30 a.m. They take 90 minutes to circumnavigate, so they create 16 circumnavigations per day along the length gradients. After about 20 days, they have scanned the earth’s surface with their highly sensitive sensor systems over all width. They move in a free constellation.

State-of-the-art camera technology as the centerpiece

The camera systems of the special fire alarm satellites consist of one optical and two infrared cameras. The bi-spectral infrared sensor system has two infrared sensors with different spectral ranges: one sensor detects electromagnetic radiation in the mid-infrared range and the other in the thermal infrared range. In addition, the visible spectral range is captured by an optical sensor. This camera, which has a higher resolution than the infrared sensors, serves to better geographical location of the thermal images.

The resolution of the camera system is impressive: the infrared cameras have a ground level abutment of only 178 meters. Unlike purely visual systems, they are also independent of weather conditions and visibility.