Aficionados consider Rosetta to be one of the most exciting missions of recent space history and Daniel Fischer, a space science writer, is among those who had been frustrated at being unable to watch.
"Imagine it's the football World Cup final, but you can't watch it live on TV," he wrote in New Scientist magazine. "The sport's governing body has decided that all but a few sample photos of it will be embargoed for half a year and that all decisions by the referee will have to be reviewed by experts over the coming months before a winner can be announced."
Enthusiasts deserved the chance to "ride along" with a mission that is costing European taxpayers 1.3 billion ($2 billion), Fischer said, to "feel the excitement as a new frontier unfolded far from Earth".
The ESA's intransigence was undermined when the French space agency CNES leaked "sensational new images of the comet's icy core". They showed a nucleus in two parts, with "a shape far weirder than any seen before - now nicknamed the rubber duck".
Following feverish Twitter debate, a group of German space enthusiasts sent an open letter to the authorities involved, calling for full access to all images from Rosetta.
The ESA has now agreed to publish an image a day from Rosetta's second camera, used for navigation purposes. The images have a resolution of one-fifth that of the main system. Images released yesterday show the craggy surface from just 500km, outlining its ridges.
As the craft approaches the comet's inner solar system, it will observe how the ice and dust of the object is heated by the Sun. In November, Rosetta will release a small lander, which should touch down on the surface of the comet, drill itself into the ice, and take photographs and measurements on the surface.
The ESA argues that the premature publication of raw images could allow other parties to publish research papers ahead of its own.
Fischer said of the relaxation: "It's a start. It's Europe's time to shine and even set a fresh precedent for public access to data. For next year two Nasa spacecraft will again be encountering new worlds up close for the first time: the dwarf planets Ceres [in March] and Pluto [July]. We still live in an exciting era of space exploration - that is, if we are allowed to share in the fun."
Rosetta and the stone
March 2004: Rosetta launched.
June 2011: To save energy, Rosetta is put into hibernation after four fly-bys of earth and Mars.
January 2014: Rosetta wakes up.
This week: Will map comet to find suitable site for lander.
November: Lander will be deployed on comet.
August 2015: Closest approach to the Sun.
December 2015: Mission ends.
- Independent