The graphic shows part of Long-March series of carrier rockets. [Xinhua photo]

A spokesperson with China's manned space program said Wednesday that fuel has been injected into the Long March-2FT1 carrier rocket in preparation for launching the Tiangong-1 space module Thursday evening as planned.

The Long March-2FT1 is the latest modified model of the Long March-2 rocket series and features a more powerful thrust force, said spokeswoman Wu Ping at a press conference at the Jiuquan Satellite Launch Center in northwest China.

The Long march-2FT1, which has been given more than 170 improvements, is 52-meters long with a payload to low Earth orbit of 8.6 tonnes, according to Wu.

The modifications to the rocket came after an unsuccessful launch in August when a Long March-2C rocket malfunctioned and failed to send an experimental satellite into orbit.

Engineers conducted comprehensive technical evaluations and made modifications to Tiangong-1's Long March-2F carrier rocket, which shares most of its components with the failed Long March-2C.

To contain the Tiangong-1 module, which is larger than China's Shenzhou manned spacecraft, the Long March-2FT1 has a larger nose fairing, according to Jing Muchun, chief designer of the Tiangong mission's carrier rocket system.

The shape of the rocket's boosters has also been modified to allow for greater fuel volume than the Long March-2F model, resulting in an increase in its thrust power, the chief designer said.

Compared with carrier rockets that the United States and Russia have used to launch moon-landing vehicles and space station components, China's Long March rocket series is much less powerful.

For example, a carrier rocket must have a payload capacity of at least 20 tonnes to send one single part of the International Space Station into low Earth orbit.

"China's manned space program aims at building up a space station, so we need a more powerful carrier rocket," Jing told Xinhua at the launch center.

"Research and development on a new, bigger carrier rocket that burns more environmentally-friendly liquid-oxygen-kerosene fuels is in progress," he said.