SpaceX

Elon Musk's commercial rocket company made a successful liftoff Monday morning from Kennedy Space Center at Cape Canaveral, Florida.

The mission was supposed to happen Sunday, but SpaceX delayed its flight because of a sensor problem on the bottom part of the rocket.

The customer for the launch was the National Reconnaissance Office, a U.S. government agency that develops and maintains spy satellites.

The mission is planned for late 2018, SpaceX CEO Elon Musk said, adding that the tourists "have already paid a significant deposit".

"This presents an opportunity for humans to return to deep space for the first time in 45 years," he said.

The two unnamed people will fly aboard a spaceship which is set for its first unmanned test flight later this year.

Mr Musk said the co-operation of America's Nasa space agency had made the plan possible.

He said the two passengers "will travel faster and further into the solar system than any before them".

In a filing to the US Federal Communications Commission (FFC), it laid out details about its plans for a 4,425-strong satellite network.

It is one of several companies aiming to deploy satellite-based internet services over the next few years.

SpaceX suffered a setback in September when a rocket exploded.

In a statement, the firm said: "Once fully deployed, the SpaceX system will pass over virtually all parts of the Earth's surface and therefore, in principle, have the ability to provide ubiquitous global service."

The space agency's inspector general office said the company's upcoming flight plan contains significant risks, as its attempts to recover from last October's launch explosion. Orbital's Antares rocket failed seconds after liftoff from Virginia, destroying the space station goods and damaging the launch complex. It was Orbital's fourth supply mission, including a 2013 test flight.

The company's founder and chief executive, Elon Musk, said Monday that these struts had flown many times before without any problem. But two minutes into the June 28 launch, one of the struts in the second stage of the unmanned Falcon 9 rocket likely broke loose. The strut was holding down a helium bottle in the liquid oxygen tank.

Musk says if the strut snapped as engineers believe, the helium bottle would have shot to the top of the tank at high speed, dooming the rocket and its Dragon supply ship for the International Space Station.

The unmanned Falcon 9 rocket carrying cargo for the International Space Station had just lifted off on June 28 when the accident occurred.

Speaking Tuesday at a conference in Boston, SpaceX founder Elon Musk said the trouble appeared to be in the upper stage, with an over-pressurization of the liquid oxygen tank. Nevertheless, the California-based company is putting ttogether what he calls a "super-detailed" timeline, millisecond by millisecond.