Star Wars #58

Star Wars #16, titled Rebel Jail, shows the Rebel penitentiary called Sunspot Prison.  Princess Leia takes Doctor Aphra, a cohort of Darth Vader, to the prison.  To keep the prison a secret from the Empire, it is hidden in the corona of a sun.  This is not the first time the Rebellion has hidden assets from the Empire in the corona of a sun.

In the original Marvel series, Princess Leia oversees the plan to hide the Rebel Fleet inside the corona of Arbra's sun.  In a story titled Sundown! in Star Wars #58, a pyramid shaped force field encapsulates the fleet and is piloted into the sun's chromosphere layer, just below the outer corona layer.  The pyramid is made up of a Kerts-Bhrg control generator and four slave generators.  Once in place, Princess Leia and other Alliance personnel debark the control generator, leaving behind a maintenance crew.  Also left behind, unbeknownst to anyone else, are C-3PO and R2-D2.  R2-D2 had discovered an issue with the control generator which causes the force field to be under-powered and renders the maintenance crew unconscious.  C-3PO contacts Princess Leia to report the issue.  As the Rebellion is paralyzed to help, R2-D2 and C-3PO execute on an idea R2-D2 has which involves them performing a space walk to connect a power cable from the control generator to one of the Rebel cruisers.  They succeed in boosting the force field's power thus saving the fleet.

Star Wars #58a - Marvel Comics, U.S. (April 1982)

Star Wars #58b - Marvel Comics, U.S. (April 1982)

The cover, by Walt Simonson, shows C-3PO and R2-D2 making the space walk.  Inside the comic, R2-D2 is covered in reflective foil while C-3PO is not.  Presumably C-3PO's gold plating provides enough insulation from the radiation so he does not require the reflective foil.  It is possible the scene on this cover takes place after the pair succeed in providing more power to the force field, making it unnecessary for R2-D2 to need the reflective foil.

While the concept is interesting and the story is mediocre, we do get to see Princess Leia in a leadership role.  In the story, Leia is giving commands and directing the personnel during the operation.  This is a side of Leia that is not shown often in the original title, but we see in The Force Awakens.