By Anatoly Zak
Russian space officials are to select the winning proposal for a new rocket intended to carry cosmonauts on missions to the Moon.
This will mark the first time since 1964 that the Russian space programme has made the Moon its main objective.
It will be only the second time since the collapse of the Soviet Union that Moscow has endorsed the development of a new space vehicle.
The rocket is expected to fly its first test mission in about 2015.
According to the objectives given by the Russian space agency (Roscosmos) to industry, a future rocket should be able to hoist a payload three times heavier than Russia's veteran Soyuz spacecraft, including twice the number of crew, and use environmentally friendly propellants.
The development of the new rocket should be accompanied by work on Russia's next-generation manned spacecraft, which will use it to get into orbit.
Russian space officials say the yet-to-be-named rocket should carry its first manned spacecraft in 2018. The project was timed to roughly coincide with the US space agency's (Nasa) plans to return astronauts to the Moon by 2020 under its Constellation programme.
However, in what seems like a case of history repeating itself, Russia is starting late in its bid to beat the US - and potentially China - to the Moon.
In 1961, President John F Kennedy met the Soviet challenge in space by launching the original US lunar effort.
Yet the Soviet government waited until 1964 before committing itself to the costly expenditure of a manned landing.
The Kremlin ultimately aborted the monumental effort after the Apollo 11 lunar module touched down on the Moon first.
In a 21st Century version of this Moon race, the US, Europe, China, India and Japan had all declared their intention to explore Earth's natural satellite, while Russia struggled to emerge from its post-Soviet economic crisis.
As Nasa starts unveiling the first prototypes of US rockets and spacecraft for lunar expeditions, Roscosmos is only starting its lunar programme.
To make matters worse, along with the new fleet of rockets and spacecraft which need to be built, the Russian government committed in 2007 to moving its main space launch site from the Baikonur Cosmodrome in Kazakhstan to Vostochny in Russia's Far East.
The new rocket is intended to carry a manned capsule to the Moon
In 2008, Roscosmos finally started quietly soliciting proposals from the industry to develop a brand-new rocket which could support lunar expeditions. All major Russian space firms reportedly vied for the government contract to build the vehicle.
While Roscosmos had never publicised details of the bidding process, a number of Russian space officials hinted that they were close to choosing a winner at the beginning of 2009.
On 14 March, Alexander Chulkov, head of the rocket and launch facilities directorate at Roscosmos, told BBC News that the agency would pick a winner by March 25.
"We have a bidding procedure, under which we made a request for proposals and now will be reviewing those proposals to determine a prime developer, based on the most interesting project from the cost-effectiveness point of view," Mr Chulkov said.
He explained that the agency's main requirement for the future manned rocket was to be able to carry no less than 20 tonnes to low-Earth orbit, with the maximum capacity of about 23 tonnes.
For comparison, the Soyuz capsule, which Soviet and Russian cosmonauts have been riding to orbit since 1967, weighs around seven tonnes. Nasa's Ares-I rocket for the next-generation Orion spacecraft will be able to lift a total of 25 tonnes.
Contenders must also employ non-toxic propellants such as kerosene or liquid hydrogen on all stages of the vehicle.
According to Mr Chulkov, industry will generally be free to design the general architecture of the future rocket.
"Roscosmos has its own opinion about the configuration (of the rocket), which we would like to see, however, we understand there is some distance between what we want and what might be available," Chulkov said.
The decision on the prime developer would clear the way to the preliminary design phase of the rocket, which was expected to last for about one year.
"Thus, in 2009 we will start the development of this rocket," Mr Chulkov said.
Although the Russian space agency is expected to name a single prime developer, it has been rumoured in unofficial fora that the contract would distribute various responsibilities for the project among several major rocket firms.
These include TsSKB Progress in Samara, the developer of the Soyuz rocket, and KB Mashinostroenia in Miass, a chief developer of submarine-launched ballistic missiles.
Thus, a bulk of the workforce building Russian rockets today will remain employed.
How heavy is heavy?
A new rocket to loft the manned spacecraft is only one component in the array of hardware that will be required to land humans on the Moon in the 21st century.
With the multi-launch scenario for a lunar expedition adopted by both Nasa and Roscosmos, a separate heavy-lift vehicle would be needed to launch the lunar landing module and the rocket stage to propel it from Earth orbit towards the Moon.
However, it seems that Nasa and Russia have a drastically different understanding of what "heavy-lift" means.
While the US space agency embarked on the development of its titanic Ares-V rocket with a payload capacity target of 145 tonnes, Russian space officials have indicated a much lower appetite for payload tonnage.
"In the field of heavy-lifting rockets we have
the yet-to-be-flown Angara (rocket), while the requirements for the next-generation rocket are within the same category," Mr Chulkov said.
The Angara rocket, which has been under development since the mid-1990s, is expected to make its maiden flight in 2011.
It would be capable of carrying as many as 35 tonnes into low-Earth orbit. But some of its derivatives could lift between 40 and 50 tonnes.
According to documents from the Khrunichev enterprise, developer of the Angara rocket, up to four launches of the Angara-7 vehicle would be required to accomplish a single lunar expedition. By comparison, Nasa can rely on one Ares-I rocket and one Ares-V for each Moon landing.