Operation Skyhook

Operation: Skyhook was the codename given to the Rebel Alliance's operation to obtain the Death Star plans and ultimately destroy the Imperial battlestation Death Star I.

Learning about the superweapon
Rumors about the existence of a massive Imperial construction existed since the rescue of the Genue. After rescuing Wookiee slaves from Toral and examining its documents, Alliance learnt the existence of a convoy of Orron III from which base they stole satellites.

The existence of the Death Star became known after the stolen satellites transmitted the schematics to the Rebel outpost AX-235 and the Rebel spies who manned it got find of the space station.

About the same time, Princess Leia Organa went on a mercy mission to deliver medical supplies and equipment to the Ralltiiri High Council. She was permitted to land by Lord Tion himself. There, Leia rescued a wounded Rebel soldier, who later revealed the existence of the first Death Star.

The Operation
When the Death Star whereabouts became more well known, the Rebels proceeded with the Mission to Danuta, during which rebel operative Kyle Katarn (who had recently defected from the Empire) was sent to retrieve the plans from a secret Imperial base in the city of Trid. Due to their importance, these plans were transported physically to Princess Leia aboard the diplomatic vessel Tantive IV. Tantive IV would then go on to the planet Toprawa, where it obtained other parts of the plans for the new battle station. In addition to the fragments gathered from Danuta and Toprawa, it seems a third piece of the plans were delievered from a rebel base on Polis Massa. Ultimately, the information was to be delivered to the Star Cruiser Liberty, but a sudden appearance of the Star Destroyer Immortal caused the transfer to stop, and Tantive IV moved to Tatooine instead, in an attempt to fulfill its second objective: Former Jedi General Obi-Wan Kenobi had survived the Great Jedi Purge and was now hiding on Tatooine. Princess Leia had been instructed by her father to seek him out if she had no other option. Leia would now attempt to bring Kenobi to Alderaan, along with the stolen plans.

Unfortunately, before the ship ever reached Tatooine, it was intercepted by the Imperial Star Destroyer Devastator, the flagship of Darth Vader.

The Tantive IV was quickly disabled and captured, and though a small struggle was made by Rebels on board, the stormtroopers of the 501st Legion quickly eliminated the Rebel troops and captured Princess Leia. However, the boarding party was unable to find the plans, which had been secretly uploaded to the astromech droid R2-D2, who then made his getaway in an escape pod.

While the Alliance was looking for the location of the Death Star, Jan Dodonna proposed that if the base of Kalla VII was destroyed, any passing ships heading fo the Death Star, would be stranded there. According to this, Red Squadron assisted to its destruction while Priam arrived and as predicted, it was stranded.

After the capture of Priam, its computer revealed to the Alliance that the location of the Death Star was Despayre. Unfortunately when Rebel scouts went to investigate, the Death Star had already left.

Conclusion
The things turned when Death Star came itself to the Rebels. Following Princess Leia who 'escaped' to Yavin, Operation Skyhook would successfully conclude with the Battle of Yavin in the moment where all odds where against the Alliance.

But the Empire would later respond with other special projects, including the Dark Trooper production line, the development of Phantom TIEs and the Tarkin battlestation. Their efforts would conclude with the TIE Experimental Project and finally the construction of the Death Star II.