The space segment, in charge of developing and launching the technically challenging EnMAP satellite, is led by OHB System AG. It covers the following mission aspects:
- Building the satellite bus
- Developing and manufacturing the payload: a sophisticated hyperspectral instrument
- Integrating and testing the entire satellite
- Procuring a flight opportunity, including launch support and preparation, and the launch itself.
The hyperspectral imager is a push-broom type consisting of two prism imaging spectrometers: one for the VNIR and one for the SWIR range. They share a common three-mirror anastigmat telescope with a field splitter placed in the telescope focal plane. In order to achieve a high signal-to-noise ratio, detectors and front-end electronics are being developed with low noise and high quantum efficiency characteristics. The SWIR detector is actively cooled to 150 K using a pulse tube cooler. The VNIR detector is thermally controlled to ±0.1 K by means of thermoelectric cooling.
Orbit and Communication
The sensors cover a swath width of 30 km with a ground sampling distance of 30 m × 30 m. The along-track dimension is given by the satellite movement. Data length up to 5000 km can be collected per day and downlinked via X-band with 320 Mbits/s in 31 minutes/day. The chosen Sun-synchronous orbit combined with a ±30° off-nadir pointing feature allows each point on Earth to be revisited within 4 days.
Platform and Launcher
The instrument is accommodated on top of the platform accounting for the demanding stability and thermal requirements of the high-resolution optical remote sensing system. The platform comprises highly accurate attitude control and a high rate data processing chain. The satellite dimensions are compatible with the fairing of the Indian PSLV (Polar Satellite Launch Vehicle) launcher, which is able to lift the satellite into the required orbit.