An explosion that destroyed a Space Exploration Technologies Corp. rocket and a satellite on the ground Thursday casts a pall over the pioneering space-transportation company run by entrepreneur Elon Musk.

In addition to worsening a backlog of delayed commercial launches, the explosion of the unmanned rocket and its aftermath are likely to complicate the company’s pursuit of additional manned and unmanned government contracts. It could take several months to determine the accident’s cause and take remedial action, according to industry officials.

The incident occurred during preparations for a routine test firing about 9 a.m. at Cape Canaveral Air Force Station in Florida. Information was sketchy, but eyewitness accounts described a series of explosions that could be felt miles away and a plume of thick smoke.

A SpaceX spokesman said there “was an anomaly on the pad resulting in the loss of the vehicle and its payload. Per standard procedure, the pad was clear and there were no injuries.” Company spokesmen were still gathering details of what happened and didn’t elaborate.

The destroyed Falcon 9 rocket had been slated to send Israel’s Space-Communications Ltd.’s Amos-6 satellite into orbit this weekend. It was part of an effort to provide internet access to people throughout large parts of sub-Saharan Africa by Facebook Inc. in collaboration with French satellite operator Eutelsat Communications SA.