NIRSpec — the main optical instrument for the James Webb Space Telescope (JWST) was built by Airbus Defence and Space. The 200-kg near infrared spectrometer will be able to observe up to 100 celestial bodies, such as galaxies and stars, at various spectral resolutions. NIRSpec’s multi-object capability means that JWST will have the ability to observe large sections of space simultaneously and in unprecedented detail. JWST will be positioned in an orbit 1.5 million km from Earth, from where NIRSpec will have to perform at temperatures of -238 °C.