1960s Russian rocket WAS to blame for Antares explosion Preliminary results point to a failure in one of its two main engines Engines were built 40 years ago in Russia Orbital says it still plans to fulfill its contract with NASA to deliver all remaining cargo to the Space Station by the end of 2016 Will introduce already-planned upgrade early in 2016 By Associated Press and Mark Prigg for MailOnline Orbital Sciences says it will 'likely' stop using the type of engines that were employed when its unmanned Antares commercial supply rocket bound for the International Space Station exploded moments after liftoff last week. The company says its investigation of the crash is continuing, but preliminary results point to a failure in one of its two main engines involved in the first stage of launch. 'As a result, the use of these engines for the Antares vehicle likely will be discontinued,' it said. The Orbital Sciences Corporation Antares rocket, with the Cygnus spacecraft onboard, explodes moments Preliminary results from the investigation point to a failure in one of its two main engines The Antares rocket was due to launch an unmanned Orbital-3 Cygnus spacecraft to deliver more than 5,000lbs of supplies to the International Space Station - including science experiments, experiment hardware, spare parts, and crew provisions - as part of a $1.9billion deal with NASA. Outfitted with a new, more powerful upper-stage engine, the Antares rocket was packed with 5,055 pounds (2,293 kg) of supplies, science experiments and equipment, a 15 percent increase over previous missions. Orbital says it still plans to fulfill its contract with NASA to deliver all remaining cargo to the Space Station by the end of 2016. 'Orbital is taking decisive action to fulfill our commitments to NASA in support of safe and productive operations of the Space Station,' David Thompson, Orbital's Chairman and Chief Executive Officer, said. 'While last week's Antares failure was very disappointing to all of us, the company is already implementing a contingency plan to overcome this setback. We intend to move forward safely but also expeditiously to put our CRS cargo program back on track and to accelerate the introduction of our upgraded Antares rocket. The engines involved are liquid oxygen and kerosene-fueled AJ26 engines made by Aerojet Rocketdyne. The engines were originally designed and produced during the Soviet era in Russia, though modifications have been made. On its website, Orbital said each AJ26 engine was sent from the Aerojet Rocketdyne facility in Sacramento, California, to the NASA/Stennis Space Center in Mississippi for hot fire acceptance testing, prior to heading to the Wallops Island, Virginia, launch site. The investigation is focusing on fact the Antares rocket that blew up on the launchpad on its way to the International Space Station last night was using a 40-year-old Russian engine of a similar design to those used during the Soviets' disastrous attempts to beat America to the moon in the 1960s, it has emerged. Old technology: The engines in question are of a similar design to those used to power Russia's ill-fated N1 series rockets which the Soviets hoped to use to beat America to the moon in the 1960s Dulles-based Orbital Sciences, which has a $1.9 billion contract to make eight supply missions to the international space station, purchased a number of the engines which had been mothballed by Russia in the 1970s, the Washington Post reports. 'They were in fact built in Russia about 40 years ago and stored in plastic bags after their Moon program was cancelled,' Jonathan McDowell, of the Harvard Smithsonian Center for Astrophysics, told NPR. Earlier incarnations of the engines had been designed to power Russia's enormous N1 rockets into orbit - however all four launches of the N1, which took place between 1969 and 1972, failed, leading the Soviet space programme to abandon attempts to put a cosmonaut on the moon. However, the Russian maker of the engine denied its product was at fault for the catastrophe. The Kuznetsov company in the Russian city of Samara suggested that modifications carried out in the US could be to blame, the Russian news agency Itar-Tass reported. 'Due to certain specifics, it's not possible to talk about the construction details of the rocket itself and the interaction of its systems during launch, since this is the field of American specialists,' Kuznetsov's press service said, according the The Guardian. 'However, it's important to note that during yesterday's launch, the AJ-26 first-stage engines, which are a modification of the NK-33, were functioning normally.' 'While the work of the AIB continues, preliminary evidence and analysis conducted to date points to a probable turbopump-related failure in one of the two Aerojet Rocketdyne AJ26 stage one main engines,' Orbital said. Conditions for the launch were perfect - but as it left the launchpad, the rocket appeared to explode. It will introduce an already-planned upgrade to the Antares propulsion system early in 2016. Orbital Sciences Corp., based in Dulles, Virginia, says there will be no cost increase for NASA and it doesn't expect costs related to the accident to be material for Orbital in 2015. Shares of Orbital Sciences rose $1.06, or 4.2 percent, to $26.18 in morning trading Wednesday.