The Air Force delayed the launch of the fifth Advanced Extremely High Frequency communications satellite June 23 after a launch vehicle battery failure was discovered during final processing.

The launch was scheduled for June 27 in Cape Canaveral, Florida, but has now been pushed to July 9 at the earliest. A technical team is evaluating the issue and replacing the battery on the United Launch Alliance Atlas V rocket which will carry the AEHF highly protected communications satellite to orbit.

The AEHF satellites are meant to replace the Milstar system, providing highly secure, jam-resistant communications for the military and national leadership. The new system provides 10 times the capacity of its predecessor, with one AEHF satellite providing more capacity than the entire Milstar constellation.

There will ultimately be six satellites, built by Lockheed Martin, in the AEHF constellation.

CORRECTION: An earlier version of this story included the incorrect number of satellites that will be in the AEHF constellation. There will be six.