A group of six students from Ocean City High School who had traveled to Walllops Island, Virginia to witness the launch of an unmanned rocket carrying their science experiment to the International Space Station, instead looked on in shock as the rocket blew up just seconds after liftoff Tuesday.

The Antares cargo rocket exploded six seconds after liftoff from the Mid-Atlantic Regional Spaceport.

The rocket was going to deliver more than 5,000lbs of supplies to the International Space Station - including science experiments, experiment hardware and spare parts.

Initial estimates of the cost of spacecraft, supplies lost in explosion is over $200 million.

According to the Press of Atlantic City, the Ocean City students and and their traveling party of 20 people were on site to watch the launch carrying their science project.

Their experiment, to analyze the effect of microgravity on the attachment rate of E. coli to romaine lettuce cells, was one of 19 chosen nationwide by the Student Spaceflight Experiments Program to take the trip into outer space.

The group from Ocean City were watching from an observation area across a body of water from the launch pad when the rocket exploded just after liftoff. The students were said to be shocked and disappointed by the explosion. They returned to South Jersey safely Tuesday night.

The mission, originally scheduled to launch Monday evening, was scrubbed 10 minutes before blastoff due to a boat in the marine hazard area. The students had expressed frustration at the postponement, one of several throughout the process, including one as recently as Oct. 14, but were looking forward to finally seeing their experiment take flight.