WASHINGTON (AP) — Envisioned in the 1990s as crucial to U.S. military superiority in the next century, the sleek, radar-evading F-22 Raptor has finally seen its first combat.

Never used in Afghanistan or Iraq, the Air Force's newest fighter jet made its combat debut this week, taking part in the second wave of airstrikes over Syria, according to the Pentagon.

Five things to know about the F-22:

1. Its first combat mission involved dropping bombs on an Islamic State group command-and-control building in Raqqa. During a Pentagon briefing Tuesday, Lt. Gen. William Mayville showed before and after slides of the airstrike targets. The after-shot for the F-22 showed a successful mission, with the command-and-control center destroyed.

2. It was developed by Lockheed Martin, with major subcontractors such as Boeing, as a 21st century fighter jet to replace various models of the aging F-15. With its stealth design, the single-seat F-22 was built to evade radar and has twin engines that allow it to fly at faster-than-sound speeds without gas-guzzling afterburners. Production of the first F-22 Raptor started in 1999 and was delivered to Air Force in 2002. The last one was delivered in 2012.

3. The F-22 comes with a hefty price tag. Each costs an average of $190 million. More than 190 F-22 fighter jets were manufactured for the U.S. military, including eight test aircraft.

4. The Raptor program was beset by design and costs overruns. When the F-22 was unveiled in 1997, critics were complaining about the costly program. At the time, the Air Force sought an order of 438 F-22s, at a cost of about $45 billion. That order was scaled back sharply. In 2010, Defense Secretary Robert Gates told Congress he was willing to cut the F-22 program as too expensive. Production was later capped.

5. Safety concerns were the issue in 2011 when the nation's F-22s were grounded for four months after pilots complained about getting dizzy and encountering a lack of oxygen in the cockpit. Internal documents obtained by The Associated Press show that, years earlier, U.S. military experts suspected flaws in the oxygen-supply system for the F-22. The Air Force later blamed a faulty valve in the pilots' pressure vests. That valve was replaced and the volume of air flowing to pilots was increased.