|Class Name :
||Nova Class 
|Unit Run :
|NCC 72381  USS Equinox  - Destroyed NCC 73515 USS Nova plus 16 others built in total. 1 have been lost in all.
2369 - 2370, class remains in service
||Length : 165 m 
Beam : 62 m
Height : 34 m
Decks : 7
127,000 metric tons
11 x Type VIII phaser arrays, total output 6,000 TeraWatts
2 x Standard photon torpedo tube  with 25 rounds
|Defence Systems :
||Standard  shield system, total capacity 688,500 TeraJoules
Standard Duranium / Tritanium Single hull.
Standard level Structural Integrity Field
(TNG scale) :
|Normal Cruise : 6
Maximum Cruise : 7
Maximum Rated : 8  for 20 hours.
|Strength Indices :
(Galaxy class = 1,000)
|Beam Firepower : 120
Torpedo Firepower : 250
Weapon Range and Accuracy : 400
Shield Strength : 255
Hull Armour : 50
Speed : 535
Combat Manoeuvrability : 9,200
|Overall Strength Index :
|Diplomatic Capability :
|Expected Hull Life :
|Refit Cycle :
||Minor : 1 year
Standard : 1 years
Major : 6 years
The Nova class was designed as a modern replacement for the long serving Oberth class science vessel. The requirement called for a ship capable of making relatively short duration missions; Starfleet intended to use these ships in the large unexplored areas between Federation controlled space, missions which would typically be staged out of Starbases and last for a few months up to a year at most. The design of the Nova class vessel was based on the Defiant pathfinder ship. 
This ship was of the right size and employed the latest warp field/hull geometry and propulsion technology. Starfleet replaced the warp core with a far less powerful version, reducing the top speed to Warp 8. 
Running the same nacelle design at much lower power greatly extended the operating life of the warp coils, reducing the ships refit schedule and making it easier to operate. The heavy weaponry was also removed, creating extra space for sensor arrays and scientific labs. Originally, the Nova designation was intended to be assigned to the replacement for the Galaxy class Explorers.  However, the Galaxy class went into high level production as a battleship in the run up to the Dominion war. 
After the war, many of these ships continued in service as fully fleshed out Explorers, while others were retired. It quickly became clear that Starfleet would have a ready supply of large space frames on hand for far longer than originally envisaged. Additionally, the entry into service of the Sovereign class introduced a new level of high technology to the fleet. Both factors reduced the need for a galaxy replacement significantly, and so the Nova development project was quietly dropped. With the name now available again, Starfleet chose to assign it to the new science ship. One of the first group of Nova class vessels - the USS Equinox - vanished shortly after launching. It was thought to have been lost, but was later discovered by Voyager to have been dragged to the Delta Quadrant by the Caretaker. The Equinox fared rather worse than Voyager in its attempts to get home; with its lower speed the Equinox faced a journey of over a hundred and eighty years in a vessel designed to operate for no more than twelve months between refits. Unfortunately, the crew discovered that the bodies of a trans-dimensional alien species could be processed to produce a powerful form of fuel, greatly increasing the ships top speed. Captain Ransom began capturing and murdering the aliens, in direct violation of both the Prime Directive and Starfleet ethics. The aliens fought back, killing many of the Equinox crew.
When Voyager encountered the Equinox they quickly realised what Ransom had done. Captain Janeway attempted to imprison the crew but they escaped, leaving Voyager under attack by the aliens. The ship survived the attack, and was able to pursue and capture most of the remaining Equinox crew. The aliens attacked the ship again, killing the remaining crew and destroying the ship. 
Construction of the Nova class was suspended shortly before the Dominion war in favour of more combat capable vessels. Now that the war is over, construction is likely to be resumed within the next year or so.
The Nova class appeared in the Voyager episode "Equinox"; up to this episode I had thought of the Intrepid class as being one of the smaller Starships in service with the Federation at about half the length of a Galaxy class, but the Nova is less than half as small again!
The ship is described in the episode as being a fairly slow low capability vessel, so I've designed the specs accordingly. That warp eight is the top speed is stated directly, as is the fact that the ship has shields and torpedo tubes. Phaser arrays are also visible on the hull. The figure of 78 for the crew comes from Captain Ransom; he tells Janeway that he lost thirty nine people in battles with a powerful enemy, which he describes as "half my crew". The rest of the specs I've pitched at a level roughly in scale with the Intrepid class.
The Nova class seem to be ideal candidates to replace the ageing Oberth class first seen in "Star Trek III : The Search for Spock", since they are about the same size, seem to fulfil an identical role, but are much more modern.