In the events of Interstellar, Brand finally reaches Edmund's planet on the starship Endurance, via Miller's and Mann's planet.
Where is the equivalent vehicle for the original 12 probes which were a part of the original Lazarus mission. Did they go through the wormhole without a vehicle like Endurance, or was there another starship they used like Endurance?
Lazarus didn't have a Endurance like ship. It's explained during the board-room scene in NASA:
PROFESSOR BRAND
Ranger launches carrying the bravest humans ever to live, led by the remarkable Dr Mann. Twelve Ranger launches
DOYLE
Each person’s landing pod had life support for two years - but they could use hibernation to stretch that, making observations on organics over a decade or more. Their mission was to assess their world, and if it showed promise, send a signal, bed down for the long nap, and wait to be rescued.
COOPER
And if their world didn’t show promise?
DOYLE
Hence the bravery.
The Lazarus missions were designed to launch 12 smaller, Ranger vehicles to each of the 12 possible colony planets. Each of these vehicles is significantly smaller than Endurance, and it's a one-way trip to these potential colony planets.
The Rangers that we see in the movie look like this:
Its possible that the Rangers used by Lazarus had supplementary engine / fuel or supply modules, but I think it's clearly meant to imply that each mission was a one-way 'shot in the dark' for each Astronaut to scout a single planet.
NASA then built the single larger Endurance to visit the most promising system, carrying the "Plan-B" population bomb to establish the colony. Endurance also has (apparently) a better range, because Cooper fully expected to be able to visit Miller's and Mann's planets before returning to the wormhole and back to Earth, if the Lazarus astronauts had that option they could return with their results and recommendations on which planet to colonize.
