A revolution in space travel will have to wait: The planned launch of a newly designed rocket in Cape Canaveral on Tuesday had to be canceled during the last minute of the countdown. The flight was aborted because of troubles with the rocket's second stage. The Falcon 9 rocket, built by the private space company SpaceX, was due to take off at 6:20 am local time. Now, the earliest possible start date is Friday, January 9.

The rocket is due to bring a Dragon transport space ship with 1.8 metric tons of payload to the International Space Station (ISS). The cargo includes essential supplies and materials for new experiments, and is the heaviest load ever on a Dragon transporter.

For SpaceX, Dragon flights with Falcon 9 rockets have become routine operations by now. But there's something different this time: for the first time in space history, the first stage of the rocket will not plop into the ocean - but rather, hopefully land on a swimming platform 91 by 30 meters in area, located on a ship 322 kilometers off the Florida coast. The second stage will bring Dragon to the ISS as usual.

Landing vertically with special wings

To prevent the first stage from being damaged by a crash upon its return to earth, the first stage's three engines will be reignited after separation. Then, the rocket will slowly fall back to earth vertically, while the engines slow the descent - at least that's what the engineers hope. Ideally, the rocket will even manage to land on the platform standing up.

On its website, SpaceX describe the maneuver as "like trying to balance a rubber broomstick on your hand in the middle of a wind storm."

In order to control the rocket during that complicated maneuver, SpaceX engineers have equipped it with special wings in an X-configuration. Previous tests have shown that the rocket was able to hover over an area in a controlled way.

At the end of these tests, however, the rocket crashed into the ocean. There will be no humans on or around the platform when the landing takes place.

Risky maneuver

SpaceX founder and chief executive Elon Musk estimates that the chances of successfully landing the rocket are about 50-50. His company considers the development of a reusable rocket a key component of reducing the costs of space travel in the future.

The start was initially planned for December 18, 2014, but had to be delayed for technical reasons. Once the rocket takes off, Dragon will need two days to reach the ISS, which currently has six astronauts working there.

NASA has contracted two private companies to deliver cargo to the ISS. Besides SpaceX with its workhorse Dragon, the company Orbital Sciences Corp. with its space-ship Cygnus also has an agreement.

But Cygnus launches have been temporarily suspended after one cargo spaceship was lost in the explosion of an Antares rocket this past October. Orbital Sciences expects to resume flights with another type of rocket later this year.