The SwissCube Telescope

Science Objective

SwissCube’s science objective is to measure the airglow emission in the upper atmosphere at about 100 km altitude to:

  1. Demonstrate the feasibility of using airglow as a basis for a low-cost earth sensor.
  2. Validate the established airglow model or bring additional information about airglow dependence on latitude, altitude and local solar time.
To achieve that scientific goal, a small telescope was built (length of 4.5 cm) which looks at the near-infrared (IR) product of the airglow. The airglow is seen as an emission of light in the green and near-infrared spectral regions. These emissions are due to the recombination of oxygen atoms (2 O into O2), which have been dissociated by the UV light of the Sun. The near-IR emission is actually the most intense.

Telescope design

SwissCube has very tight volume and mass constraints, as defined by the CubeSat standard ( Thus the SwissCube telescope had to fit within the following physical and electrical constraints: The design was performed by the academic partner HES-SO/HEIG-VD and the EPFL/LMTS. It consists of a triplet lens design with off-the-shelf components (see Figures 4,5,6), a baffle for a solar exclusion angle of 30°, with an attenuation factor of 10-4, and a filter with a central wavelength at 767 nm and a bandwidth of 20 nm. The Field of View of the telescope is 18.8° x 25°, and the resolution of each pixel is 0.16°. Each image is 188 x 120 pixels, and is around 180 kbits (22 KiB). It takes about 5 minutes to download a full image at our downlink rate of 1.2 kbps.

Figure 4. SwissCube's optical design.

Figure 5. SwissCube's telescope design.

Figure 6. SwissCube's telescope (45 mm length).