Ted Cruz, chairman of the Senate’s Subcommittee on Space, Science, and Competitiveness, said NASA should focus more on deep space exploration and less on studying the planet through Earth observing satellites. At a senate hearing over the $18.5 billion budget request for NASA’s fiscal year 2016 on Thursday, Cruz expressed concerns that the space agency had lost sight of its “core mission,” according to media reports.

“Almost any American would agree that the core function of NASA is to explore space. That's what inspires little boys and little girls across this country,” Cruz reportedly said at the hearing that was also attended by NASA Administrator Charles Bolden. “I am concerned that NASA in the current environment has lost its full focus on that core mission.”

Cruz pointed out that NASA’s budget on Earth Sciences projects had increased in recent years while its expenditure on space missions had decreased, which, he reportedly said, “does not represent a fair or appropriate allocation of resources.”

However, Bolden disagreed with the senator’s assessment, arguing that NASA’s core mission, from the very beginning, had been to “to investigate, explore space and the Earth environment, and to help us make this place a better place.”

“We can't go anywhere if the Kennedy Space Center goes underwater and we don't know it -- and that's understanding our environment,” Bolden reportedly said, referring to the sea level rise triggered by climate change. “It is absolutely critical that we understand Earth's environment because this is the only place that we have to live.”

In a letter written to Cruz on Friday, the American Geophysical Union -- a nonprofit with over 62,000 scientists from over 140 countries as its members -- backed Bolden, calling Earth sciences a “fundamental part of science.”

“Earth Science Division missions aid in flood prediction, earthquake response, and severe storm tracking across the Great Plains. Greater knowledge and prediction skill are urgent when we consider the effort, time and costs of protecting infrastructure along coasts, rebuilding fish populations, developing new water resources for manufacturing and agriculture, and restoring communities in the wake of hazards,” the Union said in the letter. “These observations, and many others like them, are integral and require the vantage point of outer space.”

Cruz’s latest comments are in line with his previous statements where he reportedly accused President Barack Obama's administration of diverting NASA from its “core priorities.”

“We need to get back to the central mission of NASA,” Cruz had reportedly said earlier, after becoming the new chairman of the subcommittee in January. Cruz has also been an outspoken climate change skeptic and has, in the past, said that there has been “no recorded warming” over the last 15 years. NASA, on the other hand, states, as part of its mission, that its role is to find answers to “critical challenges facing our planet -- climate change, sea level rise, freshwater resources and extreme weather events.”