STFC RAL Space has built its own first atom interferometer. It will be used to demonstrate the measurement of the gravitational acceleration, g, in the laboratory environment in a fountain configuration, while taking steps towards a space-qualified system for possible future gravity missions. The future gravity space missions have to provide better temporal and spatial resolution than the previous missions, GRACE and GOCE. On Earth the main limitation to the sensitivity of atom interferometers is the short interaction time due to the free fall of atoms under gravity. Their enhanced sensitivity in micro-gravity environment, however, can meet the need for demanding sciences, besides providing a platform for fundamental physics tests. Before space-qualifying, these devices need to over-come some technological challenges, involving mainly compactness, robustness, low power consumption and weight and radiation hardness, on both system and subsystem levels. The atom interferometer experiment at RAL Space uses 87Rb atoms and has so far demonstrated a successful production of a 2D MOT and a 3D MOT with the atom numbers in the order of 109, loading rate of ~107 atoms/s and the temperatures of ~40 μK. The improvement in the temperature is anticipated after the installation of compensation coils, after which next steps towards gravity measurements in the laboratory environment can be taken with aimed sensitivity of the order of 10−9 g.