Typically, a cruiser would make first contact with some new phenomenon or civilization, and then a research ship was sent in to make further studies, allowing the cruiser to move onto other duties. Although the sensor and research facilities on board a cruiser were built to meet alomst any circumstance, the research vessels were more capable of participating in long term research missions. Also, because of their small size, the research vessles were more modular in their internal arrangement, allowing each to be customized for each mission. While the cruisers did allow for some customization in terms of upgradability, it was hardly feasible or cost effective to call a cruiser into spacedock before every mission in order to customize its research facilities for a single mission objective.
An unfortunate aspect of the research vessels, though, was its lack of defenses. Although the greatest attempt was made by R&D to give the Grissom the best shield technology available, the simple truth was that they were just too small to carry shielding comperable to that of a cruiser. As such, weaponry was also kept down to a minimum, usually a single pair of forward firing laser banks. There was no room for any missile weaponry, as all the space that would be available for them were reserved for mission specific probes. But, the Grissom class was allowed a few small tactical advantages. Because of its size, the research vessel proved to be very fast at sublight speeds, allowing it to evade all but the fastest attackers. This was the only reason why these vessels were allowed into the frontier areas of space, once the cruisers who had visited those areas had determine it to be safe. The sensor array on the Grissom class also allowed it to detect any dangers before they usually detected it, allowing for a plan of escape or evasion to be implemented.
In the 2260's, Starfleet R&D decided to take advantage of new technologies being developed, resulting in the upgrading of all existing Grissom class starships to the new Oberth class. Because of this refit, a few of the original Grissom class starships survived up through the 2360's, untill the Oberth started to get phased out by newer research vessels.
Length: 96 m
Width: 71 m
Height: 39.5 m