A Global Exploration Roadmap that will introduce a 25-year scenario for visits beyond Earth orbit is being drawn up by Nasa and their counterparts around the world.  The destination?  Mars.

Some experts say that we should go directly to Mars while other, more down-to-earth enthusiasts say that we should arrive there using stepping stones.

The International Space Exploration Coordination Group, which includes representatives from Britain, Canada, the European Space Agency, France, Germany, Italy, Japan, Russia, South Korea, and the U.S., is discussing the moon versus asteroid route.

It begins with the International Space Station and expands human presence throughout the solar system, leading ultimately to human missions to explore the surface of Mars, Nasa said Tuesday in a news release. The roadmap flows from this strategy and identifies two potential pathways: 'Asteroid Next' and 'Moon Next, the space agency added.

Nasa also said that each pathway represents a mission scenario over a 25-year period describing a logical sequence of robotic and human missions.

President Barack Obama said that astronauts should board a near-Earth asteroid by 2025 and reach Mars and its moons by the mid-2030s.  

Nasa is confident that the release of this product, and subsequent refinements as circumstances within each space agency evolve, will facilitate the ability of space agencies to form the partnerships that will ensure robust and sustainable human exploration, NASA's associate administrator for human exploration and operations Bill Gerstenmaier said. 

Many scientists argue that this 25-year timetable underestimates our ability and that, with greater funding, we can do it in 10 years. 

According to CBS News, Nasa wants to send a space probe to an aloof asteroid that will scoop up a dirt sample and return it to Earth by September 2016. 

Many Americans are concerned that federal spending is already too high and that we should be spending our money on missions inherent to Earth.