Question

what are the three main parts that gaia is composed of?

the astrometry instrument, the infrared light instrument, and the pulsar camera
detailed drawings, the pulsar instrument, and the luminosity dust
the astrometry instrument, the photometric instrument, and the radial - velocity spectrometer
the photometric instrument, the star catalogue, and the telescope

Explanation:

GAIA, the Gaia space observatory, is mainly composed of an astrometry instrument for measuring positions and motions of stars, a photometric instrument for measuring star brightness, and a radial - velocity spectrometer for measuring the radial velocities of stars.

Answer:

C. the astrometry instrument, the photometric instrument, and the radial - velocity spectrometer