The U.S. Navy's top leader has determined that 2020 will be the year to get ahead in hypersonic weapons development, with a crucial flight test scheduled for later this year.

In a memo sent last week to the service, Acting Navy Secretary Thomas Modly called the development of hypersonic technologies the "Sputnik" moment of the 21st century, comparing the early 1960s-era Space Race to a new global competition that could set the U.S. apart from its adversaries into the future.

With hindsight, the Soviet Union's Sputnik satellite launch "should heighten our awareness that major technological breakthroughs such as hypersonic weapons can destabilize the global security environment and pose an existential threat to our nation," Modly said in the memo.

"In fact, the possible applications of hypersonic technologies have already changed the nature of the battlespace, much as nuclear technology did in the past century. That is why, when it comes to hypersonic weapons, our command today must be 'All Ahead Full,'" he said.

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Like nuclear weapons, officials have said hypersonic weapons can act as deterrents, as well as game changers, in responding to conflict from hundreds of miles away -- especially weapons that move at five times the speed of sound or more.

Modly's memo outlined a robust schedule for the Navy, a lead service under the Pentagon's conventional prompt global strike program, which enables the U.S. military to strike targets anywhere globally within an hour.

A flight experiment has been scheduled later this fiscal year to demonstrate the effectiveness of the Navy-designed Hypersonic Glide Body.

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The glide body vehicle accelerates to high speeds before separating its payload and gliding toward its intended target, according to the Defense Advanced Research Projects Agency. The Navy will also conduct launcher testing throughout the year, Modly said.

Last week, Defense Secretary Mark Esper said the Pentagon has "nearly doubled its long-term investment -- almost $5 billion more in FY2020 -- in hypersonics alone in the next five years."

"And our 2021 budget will be even stronger," he said at the Center for Strategic and International Studies.

When asked Thursday at a National Defense Strategy-themed discussion at Johns Hopkins School of Advanced International Studies whether China or Russia has leapfrogged the U.S. in emerging technologies like hypersonic weapons, Esper said the premise of the question "suggests we're behind. I think we're ahead in many areas."

"I think the key is to sustain that overmatch and grow it over time," he said.

But some experts question the speed with which the military is moving forward.

Kingston Reif, director of disarmament and threat reduction policy at the Arms Control Association, said that, while much advocacy has centered on keeping pace with Russia and China, the Pentagon has yet to "specify a military rationale for rushing to test and field them."

"The relevant question is whether we need hypersonic weapons to ensure penetration of advancing adversary [anti-access/area denial] capabilities and strike targets more promptly," Reif said Thursday. "In my view, that case has yet to be made, certainly not to the extent that would justify the current pedal through the floor development approach. I think more attention needs to be paid to the crisis stability and escalation risks the weapons could pose."

Of note, Modly's memo called for the Navy and Marine Corps to work closely together to accelerate how the services explore hypersonic use.

"The bottom line is that our Navy and Marine Corps team will need to move forward together, reaping the keen intellects and experiences of everyone onboard today in order to fully leverage the full potential of these new weapons in the future," he said.

It speaks to an increased joint focus as part of a larger shift toward getting the sea services more closely aligned as they prep for possible large-scale naval battles.

Last month, Marine Commandant Gen. David Berger said it was imperative the Navy and Marine Corps integrate more often, getting back to their naval roots should a fight with China arise.

"The significant thing that's driven as to where we are right now is a paradigm shift by China in moving to the sea," he said during the annual Surface Navy Association conference. "We have watched them build and expand a conventional defensive force and kind of yawned for a long time until they went to sea.

"Game-changer," Berger added.

-- Gina Harkins contributed to this report.

-- Oriana Pawlyk can be reached at oriana.pawlyk@military.com. Follow her on Twitter at @Oriana0214.

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