Elon Musk once again reiterated that a "lot can go wrong in the November launch".
The retrofitted planes will use telescopes to capture detailed images of the rare phenomenon
Found between Mars and Jupiter, it's nearly as old as the solar system.
Epps will embark on her first space mission as part of Expedition 56/57.
The aircraft has been modified to launch Virgin Orbit's LauncherOne rocket from an altitude of 35,000ft.
The launch will kick off a busy month for Nasa.
New research revealed Venus may once have had enough cloud cover to support an ocean on its surface.
The stratosphere of WASP-121b was found to contain glowing water vapour.
A total solar eclipse like the one coming up in August might not happen in the distant future.
After four decades of searching, scientists have found evidence of a kind of seismic wave in the Sun.
There's a for six-figure salary - are you up to the job?
Platinum and water are likely to be the biggest targets for space mining firms.
The agency has funded 19 small research projects which will aid its future missions as well as the US economy.
Building blocks of cell membranes found in the moon's atmosphere
Moon attached to one of the Kepler system's 'warm planets'.