The F-35 Joint Strike Fighter has been hailed as the 'most expensive weapon in history, costing $400bn.

Now, it is finally set for its first mission - following over a decade of delays.

The Marines will begin moving 16 F-35Bs to Iwakuni Air Station in Japan early next year, it has been revealed.

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The jets will deploy as part of Marine Fighter Attack Squadron 121 in early 2017, a Marine spokeswoman said. The Pentagon's director of testing recently warned it is 'not on a path toward success but instead on a path toward failing to deliver' the plane's full combat capabilities on time, according to Bloomberg.

BATTLE READY? The software on the F-35 is being constantly upgraded. In 2017, its 3F software will be rolled out, which will give the the aircraft its full war-fighting capability, including the ability to launch certain types of weapons such as the Small Diameter Bomb. Other 3F changes, like improved pilot interfaces and displays, will make the plane easier to operate. Advertisement

The Marines be the first force to deploy the Lockheed Martin jet aboard the USS Wasp next year, and will deploy a second contingent soon after, aboard the USS Essex.

'We will learn from that, and see what capabilities we need to further develop,' said Marine Lt. Gen. Robert Walsh, the commanding general of the Marines' Combat Development Command, according toDefense One.

'A lot of it's going to be the school of hard knocks.'

The jets will deploy as part of Marine Fighter Attack Squadron 121 in early 2017, a Marine spokeswoman said.

At year's end, six of that squadron's planes will attach to the 31st Marine Expeditionary Unit.

Following over a decade of de and with a price tag of $400 billion for 2,457 planes, the fifth-generation fighter has been plagued with issues.

But it appeared the tide had finally turned earlier this year when the U.S. Air Force has declared an initial squadron of Lockheed Martin Corp F-35A fighter jets ready for combat.

Now, the Pentagon's director of operational testing has poured cold water on the announcement, slamming the planes readiness.

Michael Gilmore, stated the F-35 is 'actually not on a path toward success but instead on a path toward failing to deliver' the plane's full combat capabilities on time, according to Bloomberg.

Gilmore also said the plane is 'running out of time and money' to address deficiencies

The Marines be the first force to deploy the Lockheed Martin jet aboard the USS Wasp (pictured) next year, and will deploy a second contingent soon after, aboard the USS Essex.

'Achieving full combat capability with the Joint Strike Fighter is at substantial risk' of not occurring before development is supposed to end and realistic combat testing begins, he said of the F-35.

The U.S. Air Force has declared an initial squadron of Lockheed Martin Corp F-35A fighter jets ready for combat, marking a major milestone for a program that has faced cost overruns and delays.

However, the most complex software capabilities 'are just being added' and new problems requiring fixes and verification testing 'continue to be discovered at a substantial rate,' Gilmore wrote to Air Force Secretary Deborah Lee James; General David Goldfein, the service's chief of staff; and Frank Kendall, the Pentagon's acquisitions chief.

The action is another achievement for the $379 billion program, the Pentagon's largest weapons project.

The Air Force's decision follows one by the U.S. Marine Corps in July 2015 declaring a first squadron of F-35s ready for combat.

'The U.S. Air Force decision to make the 15 F-35As ... combat ready sends a simple and powerful message to America's friends and foes alike - the F-35 can do its mission,' the program's chief, Air Force Lieutenant General Chris Bogdan, said in a statement.

Dan Grazier, a fellow of the Project On Government Oversight, said, however, 'This is nothing but a public relations stunt.'

The F-35 Joint Strike Fighter has been hailed as the 'most expensive weapon in history.' But despite a price tag of $400 billion for 2,457 planes, the fifth-generation fighter has been plagued with issues. Pictured is a F-35B aircraft prepares for a landing at Marine Corps Air Station Yuma, Arizona. Now, a new report says the craft could finally be battle ready later this year.

He added that it would not be possible to know if the F-35 jets were ready for combat until after initial operational testing.

'The program is not doing everything they wanted it to do ... But they're at a point now where it is stabilizing and so it is progress,' said Todd Harrison, a defense analyst at the Center for Strategic and International Studies

Officials say the F-35 will give the U.S. military the ability to detect enemy aircraft and other threats far beyond current ranges, allowing the jets to strike targets and disappear long before they are detected.

The U.S. Air Force plans to buy a total of 1,763 F-35A conventional takeoff and landing jets in coming years and will operate the largest F-35 fleet in the world.

Air Force General Herbert Carlisle, commander of Air Combat Command, said work to upgrade the jet would continue in areas such as software, making the displays more intuitive and boosting the ability to share information between aircraft.

HOW DOES IT COMPARE WITH ITS 1970S PREDECESSOR, THE F-16 JET? F-35 Role: Stealth multirole fighter First flight: December 15, 2006 Unit cost (not including engine): F-35A - $98million F-35B - $104million F-35C - $116million Number built: 115 (as of November 2014) Length: 15.67m Wingspan: 10.7m Height: 4.33m Max speed (F-35A): 1,930kph Armament: One of the most highly-anticipated features of the F-35 armament is the Small Diameter Bomb II (SBD II).The bomb is able to guide towards its target using laser, imaging infrared or radar homing. It can hit moving or stationary targets in any weather, or at night, with unprecedented reliability and accuracy. The 'super weapon' is predicted to be the most versatile air-to-ground munition in the Pentagon's air combat inventory. The cost per SDB II is said to be around $250,000 and the US military plans on buying as many as 17,000 of them. F-16 Role: Multirole fighter First flight: January 20, 1974 Unit cost: F-16A/B - $14.6million F-16C/D - $18.8million Number built: 4,540+ Length: 15.06m Wingspan: 9.96m Height: 4.88m Max speed (F-16C): 2,120kph Combat history: The F-16 has served in the Air Forces of 26 nations, including the U.S., Israel, Egypt, the Netherlands, Denmark and Norway. During Operation Desert Storm, the 1991 assault on Iraq, F-16s flew over 13,000 operations, more than any other Coalition aircraft. The U.S. has employed the F-16 in operations over the Balkans, Afghanistan and Libya. At its production peak in 1987, the F-16 team in Fort Worth was also making history, by producing 30 F-16s in just 30 days. Thanks to frequent upgrades improving and incorporating new technologies into the cockpit, avionics, sensors and weapons, the aircraft has become more reliable over its 40 years. Advertisement

The aircraft could provide basic air support at this point but did not have everything the final version would, such as an infrared pointer, Carlisle said, adding that he would try to get the jets deployed to Europe and the Pacific within 18 months.

Lockheed is building three models of the F-35 Lightning II for the U.S. military and 10 countries that have already ordered the jets: Britain, Australia, Norway, Italy, Turkey, Denmark, the Netherlands, Israel, South Korea and Japan.

The Pentagon's F-35 program office said it remained in negotiations with Lockheed over long-delayed contracts for the next two batches of F-35 jets, deals worth about $15 billion.

'We're seeking a fair deal for the F-35 enterprise and industry,' said F-35 program spokesman Joe DellaVedova.

The program, launched in 2001, has made strides in recent years after huge cost overruns and technical problems that sent the project's cost up nearly 70 percent.

Problems with the fighter jet included issues with the radar software and increased risk of neck injury to lower-weight pilots when they ejected from the aircraft.

Last year researchers revealed the hugely delayed and over budget project has finally fired its first shots in the air. The F-35A Lightning II completed the first three airborne gunfire bursts from its internal Gun Airborne Unit (GAU)-22/A 25mm Gatling gun system during a California test flight on October 30th

Industry and U.S. defense officials say they are working hard to continue driving down the cost of the new warplanes to $85 million per plane by 2019, as well as the cost of operating them.

Senator John McCain, the Republican chairman of the Armed Services Committee, said he welcomed the announcement but made clear he intended to keep a close eye on the hugely expensive program.

With a price tag of $400 billion for 2,457 planes, the fifth-generation fighter could finally be battle ready later this year, a new report claims.

'The Senate Armed Services Committee will continue to exercise rigorous oversight of the Joint Strike Fighter program's long-delayed System Development and Demonstration phase as well as the start of the operational test and evaluation phase,' McCain said in a statement.

To become battle ready, at least a dozen individual F-35 must demonstrate their ability to drop bombs and shoot down other planes.

Each jet must be upgraded to a specific software package, and plugged into the complex logistics cloud that manages maintenance.

Workers can be seen on the moving line and forward fuselage assembly areas for the F-35 Joint Strike Fighter at Lockheed Martin Corp's factory located in Fort Worth, Texas

ALIS: THE 'BRAINS' OF THE F35 The problem is with what the Department of Defense officials call the 'brains' of plane, also known as the Autonomic Logistics Information System (ALIS). It is designed to support operations, mission planning and to spot any maintenance issues with the vehicle. It also allows pilots to plan missions and look back at their their performance. ALIS receives Health Reporting Codes via a radio frequency downlink while the F-35 is still in flight; this enables the pre-positioning of parts and qualified maintainers so that when the aircraft lands, downtime is minimised. Advertisement

The F-35 project office had previously set an Aug. 1 target date.

The project has been plagued with delays.

The F-35 Joint Strike Fighter's record on cost, schedule and performance has been a scandal and a tragedy, Senator John McCain told senior Pentagon officials earlier this year.

McCain, the chairman of the Senate Armed Services Committee, said the aircraft's development schedule has stretched to 15 years, deliveries of the F-35 have been delayed, and costs have skyrocketed.

'It's been a scandal and the cost overruns have been disgraceful,' McCain said.

Most recently, problems with its logistics software system grounded the entire fleet.

The issue is with what the Department of Defense officials call the 'brains' of plane, also known as the Autonomic Logistics Information System (ALIS).

A Government Accountability Office report says a failure 'could take the entire fleet offline' because there is no backup system.

The report also says a lack of testing done of the software will mean it's not ready for its deployment by the Air Force in August and the Navy in 2018.

The 'brains' of the F35 are one of three major components, with the other two being the engine and airframe.

CNN points out that the software runs on ground computers rather than operating on the plane itself.

It is designed to support operations, mission planning and to spot any maintenance issues with the vehicle.

'Program officials said that if ALIS is not fully functional, the F-35 could not be operated as frequently as intended,' the report said.

'But a DoD commissioned plan found that schedule slippage and functionality problems with ALIS could lead to $20-100 billion in additional costs.'

So far, the software has been so flawed that maintenance crews have had to resort labour-intensive alternatives.

According to National Interest, in one instance maintainers had to manually burn data onto CDs and to send the massive files across a civilian WiFi network.

One major problem, the report said, is that the F-35 data produced goes through a single main operating unit which has no back up.

'The F-35 is still in development, and this is the time when technical challenges are expected,' Lt. Genernal Chris Bogdon told CNN.

'However, we believe the combined government and industry team will resolve current issues and future discoveries,' he said.

Lead defense contractor for the plane, Lockheed Martin, insists development of the logistics software is on schedule.

a new report says problems with its logistics software system could ground the entire fleet. The problem is with what the Department of Defense officials call the 'brains' of plane, also known as the Autonomic Logistics Information System (ALIS)

'As ALIS development continues, our focus is on the warfighter and delivering the most effective, efficient fleet management system to sustain the F-35 over the next five decades of operations,' said Sharon Parsley, a spokeswoman for Lockheed Martin.

'The recommendations by the GAO are in line with the actions already underway in preparation for full-rate production and worldwide sustainment.'

As well as this month's report, a recent Pentagon report has revealed a massive list of potentially lethal bugs still facing the jet. Pictured is the F-35A, which recently completed its first aerial gun test

This isn't the only problem to plague the program.

Last month, it has emerged the jets complex radar system has a problem - it keeps crashing.

The software glitch that interferes with the ability of the Lockheed Martin F-35 Lightning II Joint Strike Fighter's AN/APG-81 AESA radar working in flight.

This poses the greatest threat to delaying US Air Force (USAF) plans to declare its jets operationally deployable, a top service official told Janes.

Major General Jeffrey Harrigian, director of the air force's F-35 integration office at the Pentagon, described the problem as 'radar stability - the radar's ability to stay up and running'.

'What would happen is they'd get a signal that says either a radar degrade or a radar fail -something that would force us to restart the radar,' Maj Gen Harrigian said

Another Pentagon report revealed a massive list of potentially lethal bugs still facing the jet.

It also found problems with the computer software, including 'in fusion, electronic warfare, and weapons employment result[ing] in ambiguous threat displays, limited ability to respond to threats, and a requirement for off-board sources to provide accurate coordinates for precision attack.'

Last year researchers revealed the hugely delayed and over budget project has finally fired its first shots in the air.

The F-35A Lightning II completed the first three airborne gunfire bursts from its internal Gun Airborne Unit (GAU)-22/A 25mm Gatling gun system during a California test flight on October 30th.

The F-35 also has a smart parts system to ensure everything is working within its limits, and can warn when parts need to be replaced.

However, the computerized maintenance management System, or CMMS, 'incorrectly authorizes older/inappropriate replacement parts.' the report said.

THE EJECTOR SEAT THAT COULD KILL Pilots under 136 pounds aren't allowed to fly any F-35 variant. Pilots under 165 pounds have a 1-in-4 chance of death and 100 percent chance of serious neck injury upon ejecting, according to the testing office. 'The testing showed that the ejection seat rotates backwards after ejection. This results in the pilot's neck becoming extended, as the head moves behind the shoulders in a 'chin up' position. When the parachute inflates and begins to extract the pilot from the seat (with great force), a 'whiplash' action occurs. The rotation of the seat and resulting extension of the neck are greater for lighter weight pilots,' the report states. Sophisticated: Footage from ground testing of the F-35A stealth jet at Edwards Air Force Base in California, shows the awesome firepower of the four-barrel Gatling gun embedded in the left wing Advertisement

It also fails to detect if it's been flying too fast and 'randomly prevented user logins' into its computerised control system.

In the first live firing test, three bursts of one 30 rounds and two 60 rounds each were fired from the aircraft's four-barrel, 25-millimeter Gatling gun.

In integrating the weapon into the stealthy F 35A airframe, the gun must be kept hidden behind closed doors to reduce its radar cross section until the trigger is pulled.

'The successful aerial gun test sortie was a culmination of several years' planning, which intensified in the first half of 2015 at the Edwards F-35 Integrated Test Force (ITF) Flight Test Squadron with a team of Air Force, Lockheed Martin, Pratt & Whitney, General Dynamics, and Northrop Grumman personnel,' said Mike Glass, Edwards ITF flight test director.

'The results of this testing will be used in future blocks of testing, where the accuracy and mission effectiveness capabilities will be evaluated.'

The 25mm gun is embedded in the F-35A's left wing and is designed to be integrated in a way to maintain the F-35's very low observable criteria.

It will provide pilots with the ability to engage air-to-ground and air-to-air targets.

'At the end of the program's system development and demonstration phase in 2017, the F-35 will have an operational gun.