While NASA’s STS-121 astronauts are gearing up for a planned July 1 launch toward the International Space Station (ISS), the next orbital construction crew is checking out their space ride.

The six astronauts of NASA’s STS-115 spaceflight, an ISS construction mission aboard the Atlantis orbiter, are at the space agency’s Kennedy Space Center (KSC) in Florida to familiarize themselves with the spacecraft and its payload. Meanwhile, engineers will repair a small dent in the external tank that will fuel the STS-115 crew’s launch into orbit.

STS-115 commander Brent Jett, pilot Chris Ferguson and mission specialists Joe Tanner, Dan Burbank, Steve MacLean and Heidemarie Stefanyshyn-Piper are performing a multi-day Crew Equipment Interface Test (CEIT) at KSC. The crew will deliver a new solar array and other items to the ISS no earlier than late August.

While the STS-115 astronauts surveyed their orbiter, engineers went over plans to repair a small dent in the foam insulation covering the external tank that will fuel Atlantis’ upcoming space shot.

Tank workers accidentally bumped the tank with a mobile work platform inside NASA’s cavernous Vehicle Assembly Building, leaving a three-eighths of an inch dent in the vessel along its upper flank.

KSC spokesperson Tracy Young told SPACE.com that the dent is on the orbiter side of the fuel tank and located just left of center along the upper portion. Young said the damage will be repaired and inspected thoroughly, and will not impede NASA’s plans to launch the STS-115 mission on Aug. 28, or even earlier as a rescue flight for STS-121 should it be necessary.

While workers evaluate the tank dent, other VAB engineers completed stacking the two solid rocket boosters that will aid Atlantis’s STS-115 space shot. At KSC’s Launch Pad 39B, the space shuttle Discovery is undergoing final preparations for a July 1 liftoff on NASA’s second return to flight mission.