These craft expressed the scientific potential within the Romulan people which attempted to continue the Romulan goal of expansion and control. In order to achieve this goal, Romulan doctrine demands that the necessary intelligence and information must be obtained. This is somewhat accomplished by the Talvath which uses its myriad of sensor arrays which is only surpassed by starship level short range sensors. Practically everything not devoted to scanning is either miniaturized or removed from the science vehicle in order to make space for the scanners.
The cockpit is present in-between the forward nose and the huge sensor packs on the shoulders of the craft. Behind these sensor pods, sits a sophisticated laboratory and computer suite. While the rear of the craft is devoted to the power generators and anti-gravity system. A strong hull also allows the craft to venture into radiation zones and even allow the science vehicle to survive some level of combat without fear.
Many Romulan colonies are wary of losing these expensive mobile science platforms as it is a Romulan Senate decree that should any be lost, then the colony will be subject to a Tal Shiar investigation. (TOS video game: New Worlds)