After the explosion in September of one of its rockets, SpaceX is now ready to get back into the business of sending payloads to space, the company announced on Monday, with its next rocket headed to orbit as soon as Sunday.

In a statement, SpaceX — or more formally, Space Exploration Technologies Corporation — said that an investigation had determined the likely cause: an unexpected interplay of supercold helium and oxygen with carbon fibers and aluminum.

The statement Monday added technical details about what went wrong, and the company said it had devised workarounds to prevent a recurrence.

The cascade of explosions on Sept. 1 that destroyed a Falcon 9 rocket on the launchpad at Cape Canaveral Air Force Station in Florida was perplexing and concerning, because it occurred during what is usually regarded as a safer portion of operations — the fueling of propellants — about eight minutes before the ignition of the engines for a planned test. (The launch had been scheduled for two days later.)