VOA常速英语:Space Exploration Enthusiasts Say US Program Adrift

HOUSTON - The U.S. space agency NASA has ambitious plans for exploring Mars with the robotic rover called Curiosity, scheduled to land on the red planet in August.  But NASA's long-range plan to send a human crew there by 2030 is under fire from critics, who include some former NASA astronauts and managers.  The critics doubt such a mission will ever come about and some also question whether it should. 
 
A half century ago, NASA sent astronauts to the moon, and for the past three decades used its space shuttle for low-earth orbit missions.
 
But many veterans of NASA's glory years, such as former Johnson Space Center Director Chris Kraft, are critics of the agency's plan to send astronauts to Mars.
 
“That objective is ludicrous. It cannot be done. It cannot be done technically and, more importantly, it cannot be done financially,” Kraft said.
 
Kraft says the new Space Launch System proposed by NASA at a cost of around $5 billion is too expensive and that it would be better to utilize existing rocket systems for exploration beyond earth's orbit.  He also says an ambitious goal like sending humans to Mars requires a detailed plan with intermediate, preliminary steps, like establishing bases on the moon.
 
“We know how to go back to the moon; it is a reasonable program; it is a feasible program; it can be done with today's capabilities.”
 
 NASA's Constellation program did include such steps, but President Barack Obama cancelled it in 2010 with approval from many scientists, who wanted a more ambitious goal.

Among those who now think that was a mistake is the director of the Hayden Planetarium in New York, Neil deGrasse Tyson.

“I understand the rhetoric that we have been to the moon, so why go back? But the real answer is that we have not been to the moon in 40 years,” Tyson said.
 
Tyson says the current Mars plan is too vague.

“I think we have lost our way, in the real world. What works on paper does not always work in the real world and, in the real world, we have lost our way,” Tyson said.

David Alexander, director of the Space Institute at Rice University, puts the blame for NASA's current predicament on the politicians who tightly control the funding.
 
“A lot of people blame NASA for not having a plan or not having this and that, but, actually, they have lots of plans based on what they have been told to do by Congress and by various Congresses over the years,” Alexander said.
 
But Congress has many enthusiastic supporters of space exploration, says NASA Deputy Administrator Lori Garver.

“We work closely with appropriators and authorizers and we believe there is broad support for a stable NASA budget,” said Garver.
 
And Garver believes Congress will fund the new launch system and other technology NASA needs to get humans to Mars, fulfilling a goal that she says NASA has had in mind for decades.

“It is finally getting to the point where we are investing in the capabilities that will get us there in a time frame when people are really beginning to talk about it realistically,” Garver said.

But before that can happen, David Alexander thinks NASA administrators and the nation's leaders need to answer some fundamental questions.
 
“The biggest issue that a lot of critics are saying is 'why? Where are we going, what are we doing there, and what are we going to do with this big thing we have developed?,'” Alexander said.
 
As the U.S. Congress struggles with the national debt and how to maintain vital federal programs, it could be tempted to cut funding for a trip to another planet set many years in the future.