When Sputnik reached Earth orbit in 1957, it started a space race between the U.S. and U.S.S.R. that would last more than a decade as both nations vied to be the first to reach the moon — and the first to take tactical advantage of the new battlefield.

Now, more than 50 years later, the Defense Department is once again finding itself in a space race, this time focused on military capabilities in orbit as a resurgent Russia and emergent China seek to expand their abilities to defend, attack, and control space.

Air Force leaders insist they'll keep the service at the forefront of anything that happens above Earth's atmosphere.

"Space is critical to everything that we do in the military. Every mission that we do in the military, doesn't matter where it is, is critically dependent on space," Gen. John Hyten, the leader of Air Force Space Command (AFSPC), said in December. "There is no soldier, sailor, airman, Marine, anywhere in the world that is not critically depending on what we provide in space."

Space warfare isn't quite at the level of X-Wings and TIE Fighters yet. At the moment, everything revolves around the satellites orbiting Earth. The advantages they provide to the Pentagon are numerous: the Global Positioning System and precision navigation, satellite communications, weather monitoring, ground surveillance and spying, detection of nuclear missile launches.

Yet U.S. space systems are some of the most vulnerable military assets the Defense Department has. A small chuck of metal can easily disable a satellite, as can lasers and other electronic weapons. On the ground, a cyber-attack could cut off the military's ability to communicate with and control assets in space.

And a spy satellite becomes useless if someone spray paints over the camera — an actual offensive tactic that's been discussed among space experts.

It's not an academic exercise. In 1985, the U.S. was first able to destroy a satellite in orbit by launching a missile from a high-flying F-15 Eagle.

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China and Russia have followed suit. In 2007, the Chinese successfully targeted and destroyed one of their own satellites in orbit, and in 2013 were suspected of testing a ground-based missile launch system to destroy objects in orbit.

And just a few months ago on Nov. 18, 2015, Russia successfully tested its own satellite destroying missile.

Not only are satellites vulnerable, but they're also extremely expensive with many costing hundreds of millions of dollars. That's prompted space experts to point out that there's no faster way for an adversary to destroy billions of dollars of U.S. taxpayer money than to target satellites.

"For decades, we have really operated in a space environment that from a threat perspective was relatively benign," Maj. Gen. David Thompson, the vice commander of AFSPC, told Air Force Times. "So Air Force Space Command and those who operated space systems in general grew up in that environment … Now however the game has changed."

"Potential adversaries understand the capabilities of our space systems and the asymmetric advantage that they provide to our military forces," he continued. "It's no longer simply good enough for us to focus on operating our systems, making sure they operate properly, making sure they provide the data. We now have to look at how we ensure that happens when a potential adversary is trying to deny our use, perhaps even up to and including destroying our satellites. So we have to change the focus of the space operators in the Air Force Space Command."

Debris

Perhaps no subject keeps top space brass up at night quite like the threat of debris. Small chunks of space junk can wreak havoc with satellites, and a large cloud of debris could do enough damage to cripple human space infrastructure for years.

It's already gotten the Hollywood treatment. In 2013's "Gravity," the destruction of a Russian satellite and resulting debris cloud killed astronauts, destroyed the Space Shuttle, the Hubble Space Telescope, the International Space Station, and a Chinese space station while stranding Sandra Bullock and George Clooney floating in orbit.

But to the Air Force, the movie isn't so much fiction as it is a fear of what could happen.

Leaders are concerned about "the capabilities that [China and Russia are] producing to launch anti-satellite weapons that will destroy spacecraft in orbit, and not only destroy them but in the process create large amounts of debris," Thompson said.

"The potential harm it will cause in a space environment, by creating large amounts of debris, will impact not just our ability but everybody's ability to operate in the space domain for decades," he said.

Space presents a far different operating environment than Earth's atmosphere; so nearly all space assets — either civilian or military — are designed to be lightweight to launch and sealed against the vacuum, extreme temperatures, and cosmic radiation of space. Almost nothing is hardened to protect against kinetic strikes and collisions.

"If you ever have a war in space and you create a kinetic mess in space, 100 years from now it's still there," Hyten said. "It doesn't go away."

Space surveillance

The threat of debris is one reason the Air Force launched two surveillance satellites in 2014 whose sole duty is to keep an eye on other satellites.

The Geosynchronous Space Situational Awareness Program (GSSAP) satellites will monitor activity in space and give the Air Force a better understanding of the activities of space assets — both friendly and not. So, for example, should a U.S. satellite mysteriously go offline, Air Force leaders could look at the GSSAP surveillance to help tell if it was a malfunction or an enemy attack that disabled the satellite.

"These satellites traverse that band and give us the awareness and the understanding of what's in that band, who's there, what the capabilities of those systems on orbit might be and potentially also the intent of various objects and the owners and operators of those things in orbit," Thompson said.

Two more such satellites are scheduled for launch in 2017, doubling the surveillance capability for the U.S.

Retired Gen. William Shelton — Hyten’s predecessor as leader of Space Command — called the satellites a "neighborhood watch" for Geosynchronous Orbit, aka GEO.

That's the orbit where many of the most critical U.S. assets lay, including GPS and some missile-launch detection warning systems.

Objects orbiting around Earth are generally divided into two areas, Low Earth Orbit (LEO) and GEO.

LEO is generally considered to range from 100 miles to 1,200 miles above the Earth's surface. It's the band of space that astronauts operate in, and the location of the International Space Station.

GEO is about 22,000 miles above the Earth's surface. What makes it so critical is that in that band, objects orbit at roughly the same speed that Earth rotates. That keeps satellites positioned over a fixed point on the ground, something which has greatly aided communication and GPS.

The GSSAP surveillance satellites are critical for giving the Air Force a head's up should any potential adversaries target U.S. assets in either orbit, Hyten said.

"If you're going to GEO with a direct ascent weapon, you have four to six hours," the general said at a breakfast hosted by the Air Force Association. "There's more time to do things. That means there's more tactics available if you can figure out what those tactics are."

But if an enemy weapon targets LEO, "you have six minutes to do something about it," Hyten said.

GPS

In addition to protecting its space assets, the Air Force is upgrading many systems too. On Feb. 5, the service launched the very last GPS II satellite, and the final unit in the IIF block. In May 2017, the first GPS III satellite will launch, with greater signal strength and better accuracy, as well as anti-jamming capabilities for military navigation.

"Many people don't really understand or recognize that it is the Air Force that flies the GPS constellation, but we do," Thompson said. "We do it proudly and we've been doing it at a fully capability now for 20 years."

Aside from helping lost motorists on the highway, GPS has become a critical technology that military increasingly relies on. For the Air Force, it allows precise targeting for munitions and aids in flying remotely piloted aircraft.

Maj. Gen. Paul Johnson, the director of Operational Capability Requirements for Air Force strategic planning, noted that GPS precision has allowed the Air Force to accurately "put a bomb in a pickle barrel."

And that accuracy continues to improve. Col. Steve Whitney, the director of the Global Positioning System Directorate, said when the Air Force first started launching the GPS IIF block satellites in 2010, the margin of error for accuracy was between 90 centimeters to one meter. As of January 2016, that possible deviation was down to 42 centimeters.

A change in accuracy of 50 centimeters might not mean much for civilian navigators driving their cars, but Whitney said it can be the difference between life or death on the battlefield, ensuring a GPS-guided munition can directly hit its target, or land far enough away from troops to allow them to take cover.

"As an airman, I do have a special place in my heart for those soldiers, sailors, airman, Marines that are relaying on this capability," Whitney said.

Budget

Running GPS, however, is one of the Air Force's biggest investments, costing upwards of more than a billion dollars annually according to budget estimates.

That's one of the reasons Space Command has seen its budget typically grow over the past decade, despite some cuts for sequestration.

In 2016, the Air Force could spend upwards of $10 billion on space operations from combined public and classified budgets, according to an estimate from Space Command. That's nearly double the $5.5 billion the entire Pentagon is planning to spend on acquisitions for cybersecurity.

Granted, the need to build satellites and purchase rockets to launch are some of the most expensive activities the U.S. government is involved in. But the amount of money budgeted for space programs signifies that, like cybersecurity, the Pentagon is viewing space as one of the most critical battlefields of the future.

Though it can be difficult to get a good total estimate, the Air Force likely spent around $8 billion on space operations in 2014 and 2015, rising to the $10 billion planned spending in 2016, according to information taken from budget documents.

In a February speech discussing the DoD's budget proposal, Secretary of Defense Ash Carter promised the department would spend even more on securing space operations in 2017 and 2018, though he did not give a estimation of how much more.

Space Mission Force

In addition to satellites and physical objects, the Air Force is also working to change space operations behind the scenes so the service will be better prepared should a fight break out in orbit.

Dubbed the "Space Mission Force," the idea is to more closely integrate experienced space operators with those just joining the force.

Thompson noted that under the current system, airmen operate space systems for a few years, then move on to training, evaluation, and planning. At that point, rarely would they return to the operations center to manage the satellites.

"That's not consistent with the rest of the Air Force model," Thompson said. "If you're a young fighter pilot, you spend a lot of time flying … As you gain expertise, you go on to become an instructor, you go on to become an evaluator, you go on to do higher level jobs in the wings. But at the same time you continue to fly so that those young pilots coming in can gain the benefit and the understanding of your expertise."

Space Command has started reorganizing the 50th Space Wing, soon to be followed by the 21st and 460th Space Wings. The effort will try to create groups that include airmen of different ranks and experience levels.

"It keeps those experienced in operating weapon systems on the floor advancing our tradecraft," Thompson said. "And training those new young space operators as they come on the crews."

With the new groups getting in place, Space Command is also looking to set up a rotational schedule so airmen aren't operating the satellites 24/7. It would instead allow time off the operations floor for airmen to evaluate and learn before reengaging.

"We enter a cycle or a rotation where a set of crews focuses on operating the systems for a period of time — at this point we think four months at a time — and another set of crews during that time will focus on advanced training," Thompson said.

The service is also looking to bolster its strategic planning. In October 2015, it created the Joint Interagency Combined Space Operations Center (JICSPOC) at Schriever Air Force Base in Colorado Springs, Colo.

The JICSPOC is, essentially, a sandbox allowing the Air Force and partners from the other branches to run scenarios, test, brainstorm, and evaluate how to respond to various activities, events, or crises in space or involving space assets.

Thompson called it "an experimental test bed."

"We're conducting experiments around various operational scenarios to understand better how we need to be able to command and control space forces and our capabilities in the future faced with the growing threat and an ever integrated national security space enterprise," he said.

The JICSPOC is set to run through most of 2016, but could see its life extended if top brass feels its lessons are useful.

X-37

But while the Space Mission Force might be behind-the-scenes to the casual observer, one Air Force space program is downright opaque: The X-37B is an unmanned Air Force space plane the Pentagon has largely kept mum about since its first launch in April 2010.

The X-37B program is currently on its fourth flight. One of the two reported X-37 craft the Air Force owns launched May 20, 2015, and is designed to stay in orbit for a year or more.

The service has largely refused to answer questions about what the space plane's mission is, and whether it's designed to test concepts for a manned military spacecraft, provide surveillance on the ground, disable other nations' satellites, defend Earth from alien attack, or all of the above.

One of the few comments the military has made about the plane is available on the Air Force website.

"Technologies being tested in the program include advanced guidance, navigation and control, thermal protection systems, avionics, high temperature structures and seals, conformal reusable insulation, lightweight electromechanical flight systems, advanced propulsion systems, and autonomous orbital flight, reentry, and landing," it says.

Regardless of what the program is working on, it's likely the technology and processes involved will be at the forefront of the next generation of Air Force space operations.

Future wars

Any conflict between the U.S. and an adversary is highly likely to include a space component in the future. Whether it's trying to knock out communications, disrupt GPS, or destroy missile warning systems, the U.S. and other nations will try to find ways to eliminate each other's satellites and space assets.

"Space has become a ubiquitous element of everything that every service component, combatant commander, national intelligence organization, and leadership of the free world relies on," said retired Lt. Gen. David Deptula, the former deputy chief of staff for intelligence, surveillance and reconnaissance. "It’s very important to be on the leading edge of capitalizing on new technologies to keep us ahead of potential adversary moves."

The fall of the Berlin Wall and collapse of the Soviet Union may have "lulled people into a false sense of security" when it comes to space, he said.

"Adversaries have not gone away, and the fact of the matter is as long as human beings populate this earth there will be conflict," Deptula said. "Not because we want it, but if it is brought to us through potential future conflict, we need to be able to succeed and be prepared for it."