Space X had their saturday launch from the Kennedy Space Center cancelled due to weather. It's been rescheduled for tomorrow. And IIRC, this may be the first commercial space launch to go to the International Space Station.
Not weather, computers aborted the countdown a half-second before launch Saturday due to high pressure in one of the Falcon 9 rocket's nine first stage engines. Engineers opted to replace a check valve in the first stage's center engine - engine No. 5 - after inspections.
SpaceX has swapped out a faulty check valve on a Merlin engine on the Falcon 9 rocket and approved plans for a second launch attempt at 3:44 a.m. EDT (0744 GMT) Tuesday.
Yes, it is the 1st commercial adventure... hopefully this all works out, they need this.