As well as its main Asteroid Framing Camera, Hera will be equipped with a compact lidar – or laser radar – to measure surface altimetry to support scientific mapping as well as support close-range asteroid operations, known as the Planetary Altimeter or PALT. A thermal infrared instrument, TIRA, will gather additional data on Didymoon's surface composition. And radio science experiments to assess Doppler shifts and other perturbations of Hera’s radio signal back to Earth, offer a way to measure Didymoon’s mass.