Less then 40 days to go for the NuSTAR launch: http://www.nustar.caltech.edu/about-nustar

NASA's NuSTAR X-ray astrophysics observatory, grounded in March by concerns with its Orbital Sciences Corp Pegasus rocket, will have an opportunity to launch in June from a remote Pacific military base.
The Pegasus booster has flown 40 times, and the upcoming launch will mark the 25th mission of the Pegasus XL configuration, which features more powerful rocket motors than earlier versions.