SpaceX has a momentous launch this week

Enlarge / The rocket launching Tuesday first flew on June 3, 2017, and then (shown here) landed back on the Florida coast. (credit: SpaceX)

SpaceX will attempt to launch its 17th mission of 2017 on Tuesday, a cargo supply flight to the International Space Station. Liftoff is scheduled for 11:46am ET, and weather conditions are expected to be near perfect, with a 90 percent chance of go conditions.

This flight is notable for several reasons. Already this year SpaceX has re-flown one of its Falcon 9 rockets, and reused a Dragon spacecraft for a station supply mission. This mission will combine both, marking the first time SpaceX has used a "flight proven" booster for a NASA launch and combined it with a used Dragon spacecraft. This booster first flew in July (also on an ISS cargo mission), and the spacecraft first flew to the station in 2015.

The launch attempt also marks a return to an old launch pad for the California-based company. When a Falcon 9 and its satellite payload blew up in September, 2016, the explosion did significant damage to Space Launch Complex 40 in Cape Canaveral, Florida. The launch pad has been out of service since then.