A supply ship is on its way to the International Space Station, despite initial fears a strong storm on the surface of the sun might cause the rocket to veer off course.
Orbital Sciences Corporation launched the unmanned Antares rocket from the U.S. state of Virginia at midday Thursday.
Orbital Sciences earlier said the size of the solar storm this week could interfere with electronic equipment aboard the unmanned supply rocket, especially during the critical launch sequence. The U.S. space agency NASA had delayed the delivery three times since December.
Officials say the solar activity poses no threat to the astronauts now on board the space station.
Wednesday NASA said it will keep the International Space Station operating for an additional four years, until 2024.
The $100 billion orbital station has been in service for 15 years.
A rotating crew of six scientists and fliers from the United States, Russia, Europe, Canada and Japan mans the station.
Since NASA retired its fleet of Space Shuttles, the agency is using Orbital Sciences and another private American company, SpaceX, to keep the space station stocked, with additional support by Russia.
Flight crews are ferried up to the space station three at a time aboard Russian Soyuz spacecraft.
Some information was provided by AP.