HOUSTON -- The Russians are itching to send a human crew to Marsand are miffed that NASA remains undecided on such an undertaking.

A leading expert in human Mars missions, Leonid Gorshkov of RSC Energia in Russia sketched out a reusable Interplanetary Expedition Complex for dispatching a crew to Mars in 2022.

Here at the World Space Congress, Gorshkov challenged NASA to move up a humans-to-Mars mission and make it a high priority.

A human Mars mission "is a very serious thing," in Russia Gorshkov said, underscoring decades of plans that contain technical solutions to achieve such a goal. Russian space designers have blueprinted a Mars vehicle that would have a lifetime of 15 years and after servicing could be used again.

Gorshkov said that "this is the most reliable concept at present."

"We believe it has to be an international project. However, we can see that NASA considers an expedition to Mars as one of the lowest priorities. So we end up being in an awkward situation," Gorshkov said.

Gorshkov said that they have a simplified, less expensive Mars mission that would have a crew orbit the red planet. Through telerobotics, that expedition would "send their eyes and hands down to Mars," he said.

"Its important for me to convince you that human flight to Mars is a reality," Gorshkov said. "When the wheel was first invented it probably wasnt extremely useful right away, but it became very useful later," he said.

"Its not clear where we are going beyond Earth orbit," said Wes Huntress, Director of the Geophysical Laboratory at the Carnegie Institution of Washington. "After Apollo the goal became hardware instead of a destination," he said.

Huntress said the International Space Station has often been touted as "the next step". "But everyone in the public wants to know: To What?"

Huntress singled out the L2 Sun-Earth libration point as an area needing development a spot where human and robotic talent can support scientific studies far from Earth. "I think we need to set a destination for human exploration and then to systematically pursue its fulfillment in a step by step fashion with both robotic and human spaceflight," he said.

Robert Farquhar of the Johns Hopkins University Applied Physics Laboratory

Farquhar supported a one-year roundtrip asteroid trip in 2025 as "a candidate mission for the future."

"I think were still pretty adventurous with our robotic missions. But our human program has probably become less adventurous because weve been stuck in Earth orbit for a long time."

Farquhar said he advocates an evolutionary, "slow but sure" approach to getting to Mars. "I personally dont think were going to get the monies that are necessary to get us to Mars right off the bat. I think we have to go step by step," he said.

John Young, Associate Director (Technical) for the Johnson Space Center, said human exploration is the key to the future of the human race. Data regarding asteroid impacts and the threat from super volcanoes are worries for humanity, he emphasized.

"We should be running scared in exploring the solar system with human beings. We should be running fast," Young emphasized.

A former Gemini astronaut, Apollo 16 moonwalker, and space shuttle commander, Young said chances are high that Earth will experience a "civilization-ending event" in the next 100 years.

"The long term benefit of the human space exploration is saving that great gang that we all belong tothe human race. Exploration is about thatand we need to get on with it in a hurry," Young said.

Junichiro Kawaguchi of Japans Institute of Space and Astronautical Science (ISAS) said his country has not significant effort in sending humans beyond Earth orbit. He noted robotic research is not favored in Japan "for the time being," but there is growing "what next" interest.

Kawaguchi said that human spaceflight undertaken by other nations, such as China, may well stimulate Japan to move out on human exploration.

Jean-Pierre Haignere, a European Space Agency (ESA) astronaut, highlighted ESAs Aurora program. That activity calls for a human Mars mission in the 2025-2030 time frame, he said. A decision point on doing so is slated for 2015.