Former NASA astronaut Leroy Chiao discusses the upcoming mission, which will involve the X-37B Orbital Test Vehicle, an uncrewed, autonomous spacecraft.

A not-so-secret, secret reusable spaceplane operated by the United States Space Force is scheduled to lift off from the Kennedy Space Center in Florida.

A not-so-secret, secret reusable spaceplane operated by the United States Space Force is scheduled to lift off from the Kennedy Space Center in Florida.

Former Army helicopter pilot Kevin Bubolz is on a "Mission to Spread Smiles" with his two therapy dogs, Ellie and Emma.

Lt. Gen. Michael Borgschulte has become the first Marine Corps officer to be superintendent of the U.S. Naval Academy in its 180-year history

The Air Force says in a new memo that transgender airmen ousted under a recent Trump administration directive will no longer have the chance to argue before a board of their peers for the right to continue serving their country

The high-stakes summit at the Anchorage Air Force base comes as the U.S. seeks a ceasefire in the Russia-Ukraine war.

Residents in one Washington, D.C., neighborhood protested the arrival of National Guard troops in the city as President Trump continues efforts to ramp-up crime enforcement in the nation's capital.

Forces made 43 arrests on Tuesday night, according to a White House official.

A 100-year-old WWII veteran took flight in a P-51 Mustang over California, returning to the same aircraft he flew in combat missions seven decades ago.

David Muir shares the story of 100-year-old World War II veteran Joseph Peterburs and the moment he was cleared for takeoff at the controls of the same type of plane he flew 125 combat missions in.

Trump has directed the Pentagon to prepare options for the possible use of U.S. military force against drug cartels designated as terrorist organizations, officials say.

Master Sgt. Logan Ireland reflects on the Air Force's decision to deny early retirement for transgender service members being forced out of the military amid Trump's ban.

Transgender Air Force members who applied for early retirement are being denied and will have to separate from the military without any retirement benefits, according to the Pentagon.

Six soldiers tackled the suspect after he allegedly shot and wounded five other soldiers at Fort Stewart in Georgia.

First Sgt. Joshua Arnold told ABC News he was in a conference room when he heard a noise and then saw a "flash."

When a gunman opened fire at Fort Stewart in Georgia, six soldiers immediately jumped into action to stop the shooter, the secretary of the Army said.

A U.S. Army sergeant allegedly shot and wounded five other soldiers at Fort Stewart in Georgia, using his personal handgun, officials said.

Active-shooter drills at military bases have become standard to prepare for incidents similar to Wednesday's incident at Fort Stewart in Georgia.

A U.S. Army soldier was arrested Wednesday and charged with attempting to share sensitive information about U.S. military tank capabilities with Russia.

Cadet Neil Edara was attending Cadet Summer Training and died after he became unresponsive while conducting land navigation training at Fort Knox in Kentucky.

A 22-year-old Army ROTC cadet died during summer training at Fort Knox, Kentucky, officials said in a statement over the weekend.

The U.S. Air Force said the craft made a "precautionary landing."

The Department of Homeland Security has announced a new special TSA security lane designated exclusively for military members.

Gregg Jackson, 40, from Santa Rosa, California, was arrested for impersonating a law enforcement officer and a bounty hunter, according to the Sonoma County Sheriff's Office.

A large immigration enforcement operation is underway in Los Angeles with U.S. troops on the ground.

B-2 pilots invited to the White House as Trump pushes back against questions on Iran strike and claims 'devastated' pilots.

Parnell's assessment much more optimistic than UN nuclear watchdog

Defense Secretary Pete Hegseth announced on Friday the USNS Harvey Milk is being renamed the USNS Oscar V. Peterson.

The Pentagon unveiled details about a 15-year top-secret program.

Speaker Mike Johnson, Secretary of Defense Pete Hegseth and others honored U.S. Army Rangers who served in WWII on Thursday.

Two of the five surviving Army Rangers, among the 6,500 who served in World War II, attended a Congressional Gold Medal ceremony at the Capitol on Thursday.

The Joints Chiefs chairman referred damage assessments to intelligence agencies.

Lt. Col. Brandon Mace traces his family's military history from the American Revolution to the modern era with ABC News Live anchor Kyra Phillips as the Army celebrates its 250th anniversary.

Secretary of Defense Pete Hegseth said in a press conference on Thursday morning that the bombing of Iran was the most "complex and secretive military operation in history."

Defense Secretary Pete Hegseth and Joint Chiefs Chairman Gen. Dan Caine held a press conference Thursday to detail U.S. strikes over the weekend on Iranian nuclear facilities.

Retired Gen. Robert Spalding joined ABC News Live to discuss a preliminary U.S. intelligence assessment that found Trump-ordered strikes only set back Iran's nuclear program by months.

President Trump warned Iran against retaliation several times after the U.S. struck Tehran's nuclear facilities. On Monday, Tehran targeted a U.S. military base.

A retired B-2 bomber pilot reveals details about the historic U.S. strike on Iran, including stealth tactics, pilot preparations and decadelong planning.

The U.S. Department of State has issued an advisory for Americans to exercise increased caution worldwide following airstrikes on Iran.

Iran's attack on a U.S. base in Qatar has ended, there are no reports of casualties. The attacks were retaliation for the U.S. strikes on Iran's nuclear facilities.

Retired U.S. Air Force pilot Jeffrey Needles reacts to the military operation carried out by the U.S. military over the weekend to attack Iran's nuclear sites.

Qatari air defenses "successfully intercepted" a missile attack targeting Al Udeid Air Base, the Qatari Defense Ministry said.

ABC News contributor Steve Hill says there is a path for Iran to retaliate which wouldn’t provoke another round of attacks from the U.S.

Retired Gen. Robert Spalding discusses the training and deception needed to pull off the strike on three nuclear sites in Iran.

There are around 40,000 American troops in the region, spread between permanent bases and smaller outposts, and any of them could face reprisals following the U.S. bombing operation in Iran.

ABC News’ military analyst, former Marine Col. Steve Ganyard discusses the U.S. using "bunker buster" bombs for the first time on Iran and the damage they caused.

ABC News’ Martha Raddatz reports on growing concern of the 40,000 troops spread from Iraq, Bahrain, Qatar and Syria becoming targeted after Iran strike.

The Pentagon revealed stunning new details about the surprise U.S. attack on Iran dubbed "Operation Midnight Hammer" as the first video emerges of the strike and Iran vows to retaliate.

Decorated former Navy fighter pilot Matthew “Whiz” Buckley joins ABC News Live to discuss military operations in the Iran attacks.