WASHINGTON — The White House’s nominee to lead the Defense Department told lawmakers that China could soon threaten the military’s space capabilities and that under his leadership the Pentagon would certify new companies to launch national security satellites “as quickly as possible.”

In written responses to questions from the Senate Armed Services Committee, Ashton Carter, who at press time was awaiting confirmation as U.S. secretary of defense, also carefully avoided committing the department to any long-term military space programs.

U.S. President Barack Obama nominated Carter, a former deputy secretary of defense, Dec. 5 to succeed Chuck Hagel. A confirmation hearing was held Feb. 4 and the Senate could vote on the nomination as early as the week of Feb. 9.

In a 91-page response to policy questions from lawmakers, Carter addressed 17 space-related queries. Many of those queries focused on weapons in space, China’s capabilities and how to enhance competition to the national security launch market, which currently is dominated by United Launch Alliance.

Carter said he recognized “the growing challenges in the space domain,” echoing warnings by other U.S. military and intelligence officials in recent years, particularly with regard to China and Russia.

Asked whether China’s space activities should “inform U.S. space policy and programs,” Carter said Beijing “is rapidly developing space capabilities of its own that both mirror U.S. capabilities and could threaten our access and use of space for national security purposes.”

Carter said he would “determine the best way to defend U.S. space systems and to deny those advantages to those who would use space to target U.S. warfighters.”

Sen. John McCain, the committee’s chairman, opened the confirmation hearing with a list of complaints about wasteful Pentagon spending and accused the Air Force of “actively keeping” SpaceX out of the national security launch market. SpaceX of Hawthorne, California, is awaiting Air Force certification to launch national security satellites but the process has taken longer than anyone expected.

“The cost of the Evolved Expendable Launch Vehicle [program] has exploded from around $100 million per launch to $400 million per launch over the last 15 years after the Air Force allowed years of sole-source contracts while, especially over the last few months, actively keeping out any other companies from competing,” McCain said. “Hopefully this year we will see the Air Force certify a new entrant, and this competition can finally bring down costs and end our reliance on Russian rocket engines.”

Although McCain did not mention SpaceX by name, there is little doubt he was referring to that company’s effort to break ULA’s monopoly. ULA, a Boeing-Lockheed Martin joint venture, builds and operates the Atlas 5 and Delta 4 rockets developed under the Air Force’s Evolved Expendable Launch Vehicle program.

“If confirmed, I will encourage competition from new entrants by ensuring the department has a clear understanding of the certification process and by making every effort to certify all capable new entrants as quickly as possible,” Carter said.

On Jan. 16, Deborah Lee James, the Air Force secretary, announced that retired U.S. Air Force Gen. Larry D. Welch, a former chief of staff, will lead an independent review of the service’s certification process.

In response to other questions, Carter avoided committing the Defense Department, and specifically the Air Force, to any future satellite programs. Senators asked Carter for his views on the Space Based Infrared System for missile warning, Advanced Extremely High Frequency secure satellite communications system, hosting military payloads aboard commercial satellites and moving away from exquisite satellites.

Carter was noncommittal on all of those questions, saying only that he would encourage the Defense Department to study alternatives.