President Obama’s proposal to cancel NASA’s Constellation Program encountered another round of stiff, bi-partisan opposition from a House oversight panel on Wednesday, as an agency official and an outside aerospace expert painted an uncertain picture of what will take the place of the six-year-old lunar exploration initiative.

In the nearly three hours of testimony, it was clear the space agency is still in the earliest stages of defining a new direction.

That was especially the case with the White House proposal to follow the retirement of NASA’s space shuttle later this year with a $6 billion initiative to foster a commercial space transportation industry to carry astronauts as well as cargo to the International Space Station. The spending plan has met opposition from Democrats as well as Republicans at hearings before House and Senate policy and appropriations committees since it was unveiled early last month.

Thomas Young, a retired Lockheed Martin executive who has advised the Pentagon as well as the space agency on major policy issues, urged the House Space and Aeronautics Subcommittee to reject the changes outlined in NASA’s 2011 budget proposal.

“I believe we are a long way from having a commercial industry capable of satisfying human space transportation needs,” Young told the panel. “In my view, this is a risk too high and not a responsible course. The commercial crew option should not be approved.”

He urged the panel to stick with the under funded and behind schedule Constellation Program. Constellation’s Ares 1 rocket and Orion crew exploration vehicle offer the most promising means of transporting astronauts to the space station and making journeys to the moon with the larger Ares V rocket, Young said.

Instead, the White House strategy would invest billions of dollars in a wide range of new technologies intended to lower the cost of future human space exploration. The new strategy calls for a flexible path that includes missions to asteroids, the moons of Mars and Mars as well as the Earth’s moon without establishing clear goals and times lines.

“A detailed exploration plan with destinations, dates and implementation plans is needed,” said Young. “A technology program without focus and identified mission uses can result in wasteful, nonproductive, hobby shop activities.”

All but one member of the House panel seemed to agree. Doug Cooke, NASA’s associate administrator for exploration, attempted but was unable to provide many of the specifics the lawmakers sought to answers about job losses, flight risks, financial terms and operational dates for a new fleet of commercial space taxis.

The cost of establishing Constellation in response to a directive from President Bush and then dismantling the initiative was estimated at $14 billion by the subcommittee. More than $9 billion has been spend so far on Ares 1 and Orion.

“We have very serious issues to address, the future of America’s human space flight program,” said U. S. Rep. Gabrielle Giffords, the Arizona Democrat who chairs the subcommittee. “The Congress and the President need to get this one right. The clock is ticking.”

The panel expressed hope Obama will address many of their questions during a space policy summit he plans to host at NASA’s Kennedy Space Center on April 15.

“There are many questions to be asked and information yet to be provided about such a major re-direction,” said U. S. Rep. Pete Olson, of Texas, the panel’s ranking Republican. “Frankly, too many people are behaving like this is a fait accompli. That is far from the truth. There are still too many unknowns and too many issues that must be evaluated before Congress can make an informed decision.”

U. S. Rep. Dana Rohrabacher found himself largely alone arguing the merits of the Obama plan, which the California Republican compared to past policies that awarded the fledgling airlines contracts to carry the mail in the early 20th century and offered land to expanding railroad companies in the 19th century.

“Today, we are on the verge of a huge step forward into space, where a huge number of people can be engaged in enterprise in space,” he complained. “And we have the argument instead that this must be a government-based operation.”

The president’s policy initiative followed a lengthy re-assessment of the Constellation Program last year by the Augustine Committee a panel of experts chartered by the White House. It found the program so under funded that it was more than a decade behind President Bush’s goal of reaching the moon with American explorers by 2020. It urged the Obama administration to consider an annual increase of $3 billion in NASA’s budget in order to establish sustained global lead in future human exploration.

U. S. Rep. Donna Edwards, a Maryland Democrat, seemed to express the sentiments of many colleagues Wednesday, when she urged NASA not to move too quickly in the dismantling of Constellation.

“This is a work in progress,” said Edwards.