The Orbital Sciences rocket that exploded after launch was powered by a pair of rocket engines that were made during the Soviet era and refurbished, experts said Wednesday.

The Ukrainian-designed AJ-26 engines date back to the 1960s and 1970s, and Aerojet Rocketdyne of Sacramento, California has a stockpile that it refurbishes for Orbital Sciences.

Orbital described the AJ-26 engine on its web site as "a commercial derivative of the engine that was first developed for the Russian moon rocket that would have taken cosmonauts to the moon."

In 2010, the company announced it would use the engines for its Taurus II rocket because "it achieves very high performance in a lightweight, compact package."

The Soviet Union poured $1.3 billion in investment over a 10-year period into developing the engines and building more than 200 of them in all, Orbital said.

Space analyst Marco Caceres of the Teal Group told AFP that the AJ-26 is "a powerful engine" that was designed to launch people to the moon, but never did.

"They did have problems with that engine back in the '60s and ultimately they stopped manufacturing it," he said.

In 1993, Aerojet began developing design modifications to make the engine suitable for commercial launches.

The staged-combustion, oxygen kerosene engines underwent testing at NASA's Stennis facility in Mississippi.

In May, an AJ-26 engine blew up during a ground test there, but in the immediate aftermath of Tuesday's accident, officials declined to link the two incidents.

Orbital Sciences has begun investigating the cause of the rocket failure at Wallops Island, Virginia but has not released any conclusions yet.

Orbital engineers said there was no alarming signs leading up to the sunset launch.

The accident was the first catastrophic failure since private companies began supplying the International Space Station in 2010.

- Order to detonate -

The rocket exploded about six seconds after it lifted off from the seaside launch pad Tuesday at 6:22 pm (2222 GMT).

A ground controller at Wallops Island issued a command to destroy the vehicle, Orbital representatives said in a press conference late Tuesday, but gave no details on why.

"It is kind of standard procedure, that if you get something in your readings that indicate it is going to fail, you would detonate it sooner rather than later," explained Caceres.

"You don't want that vehicle to fly very high if you know it is going to fail."

John Logsdon, former director of the Space Policy Institute at George Washington University, agreed.

"There was something dramatic happening to lead the range safety officer to issue a destruct command," Logsdon told AFP.

"They know that something was really wrong and they have all the data from the rocket so it should not take long to find out what went wrong."

It was also the first attempt to launch the Antares 130, a more powerful kind of Antares than the 110 and 120 models that have flown in the past.

"I imagine they will be looking at a lot of issues," said Caceres, including whether there was too much weight on the rocket, or if there was a fuel leak or a corrosion problem.

Russian space station resupply rocket launches, doesn't explode
Washington (UPI) Oct 29, 2014 -A day after a space station resupply rocket exploded in midair only seconds after launching from Wallops Island, in Virginia, the Russian space agency made things look embarrassingly easy -- successfully linking up a ship full of precious cargo with the International Space Station.

Launched early Wednesday morning, the Progress M-25M spacecraft (also known as 57P) docked and delivered supplies to ISS astronauts only hours after taking off from Baikonur Cosmodrome in Kazakhstan. The cargo ship was carried into space by a Russian Soyuz rocket -- three tons of supplies in tow.

The successful launch and linkup completed a reversal of fortunes and upturned the recent narratives surrounding the space programs of the U.S. and Russia. A series of high profile mistakes have had Russian space officials blushing in recent months, while commercial space flight companies in the U.S. have forged ahead with expanding capabilities and new, improved technologies.

But with the explosion of Orbital Sciences' Antares rocket Tuesday evening -- just a day after its the launch was postponed by the unexpected presence of a stray boat -- Russia's tried and true Soyuz rockets are looking a bit better.

Tuesday's explosion not only destroyed the robotic cargo ship and rocket built by the Virginia-based company, but also obliterated more than 2 1/2 tons of supply materials. NASA officials said they were investigating the mishap, but insisted ISS astronauts would manage fine without the delivery and that NASA's work with Orbital would be undeterred.

"Orbital has demonstrated extraordinary capabilities in its first two missions to the station earlier this year, and we know they can replicate that success," William Gerstenmaier, Associate Administrator of NASA's Human Exploration and Operations Directorate, said in a press release after the incident.

"Launching rockets is an incredibly difficult undertaking, and we learn from each success and each setback," Gerstenmaier added. "Today's launch attempt will not deter us from our work to expand our already successful capability to launch cargo from American shores to the International Space Station."

Ahead of Tuesday's rescheduled Antares rocket launch, NASA officials predicted the blastoff would be visible (weather permitting) up and down the Eastern Seaboard. They didn't expect, however, that it would be an exploding fireball lighting up the skies.