Final answer:
Sub-metre spatial resolution satellites use sensors in the visible light, near-infrared, and short-wave infrared parts of the electromagnetic spectrum. They excel at environmental monitoring, urban planning, and national security surveillance. Low-temperature sensors are necessary for observing very cold environments to reduce thermal noise.
Step-by-step explanation:
Satellite sensor bands are specified portions of the electromagnetic spectrum that satellites are designed to detect. A satellite with sub-metre spatial resolution is typically equipped with sensors in the visible light bands, near-infrared, and sometimes short-wave infrared parts of the spectrum. These bands fall into the range of approximately 400 to 2500 nanometers (nm) where the visible spectrum ranges from about 400 to 700 nm, and the near to short-wave infrared spectra extend from 700 nm to 2500 nm.
Three things that a satellite with sub-metre spatial resolution is best suited to observe include:
- Environmental monitoring: This can include tracking deforestation, monitoring the health of agricultural fields, and assessing water quality in bodies of water.
- Urban planning: High-resolution imagery is used to manage urban growth, maintain infrastructure, and assist in disaster response and recovery efforts.
- National security: For detailed surveillance purposes, such as identifying and monitoring military assets and installations.
Satellites designed to observe extremely cold environments, like the cold (3 K) dark space, require low-temperature sensors to reduce thermal noise and increase sensitivity. This is because any heat generated by the satellite itself can be detected as radiation, interfering with the observations.