SpaceX has already postponed a critical resupply mission to the International Space Station, and the company hopes to avoid a third with its next launch window opening Friday morning. The launch, scheduled to take off from Kennedy Space Center in Florida, would be the 6th delivery to the ISS this year, and if it doesn’t happen SpaceX could be in a bit of a bind.

SpaceX had hoped to make this launch earlier this month, but a string of setbacks has pushed it to the middle of the month. Right now, the six astronauts on the ISS still have everything they need, as typically the station will have six months worth of supplies, but the problems are causing headaches for both SpaceX and NASA.

The last resupply deliver was in November, when Orbital ATK shipped supplies to the station, so it hasn’t been that long since the astronauts got new supplies. Unfortunately, if SpaceX doesn’t launch on Friday, the company will need to wait even longer to make a launch as the crew will be in the midst of a rotation that will prevent a delivery.

“NASA and SpaceX are now targeting no earlier than 10:36 a.m. EST Friday, Dec. 15, for the company’s 13th commercial resupply services mission to the International Space Station,” a NASA statement reads. “SpaceX is taking additional time for the team to conduct full inspections and cleanings due to detection of particles in the second stage fuel system. The next launch opportunity would be no earlier than late December. Meteorologists with the U.S. Air Force 45th Space Wing are predicting an 80 percent chance of favorable weather for liftoff on Friday.”