Americans might be surprised to learn that NASA didn't just hire one private contractor, SpaceX, to ferry supplies to the International Space Station. In fact, the space agency hired two. The second is Orbital Sciences, a 30-year-old successful rocket company now trying to regroup after Tuesday night's spectacular explosion on a launch pad in Virginia. Like Elon Musk's SpaceX, Orbital Sciences contracts out space launch services, and both companies have been successful. That's where the similarities may end.

In this handout photo provided by NASA, The Orbital Sciences Corporation Antares rocket, with the Cygnus spacecraft onboard, is seen being raised into vertical position on launch Pad-0A, Saturday, Oct. 25, 2014, at NASA's Wallops Flight Facility in Virginia. Getty Images

Unlike SpaceX, where Musk stages dramatic unveilings and makes headline grabbing pronouncements, Orbital Sciences is a quiet company formed in 1982 by three friends from Harvard Business School. It has built a reputation in both commercial satellite manufacturing and launch, as well as military missile tests, with over 500 missions and a total of 1,000 years of in-orbit operations. Orbital even scored a larger contract for fewer trips to the ISS than SpaceX did: $1.9 billion for eight trips, versus $1.6 billion awarded to SpaceX for 12.

Also unlike SpaceX, Orbital is a publicly traded company. Just two weeks ago, the company raised its full year guidance and expressed hope it would complete a merger with rocket rival ATK by the end of the year. However, as of midday Wednesday, shares were down more than 15 percent, wiping out nearly $300 million in market cap. Read More Rocket explodes on launch

Because unlike SpaceX, Orbital Sciences has now had a failure to launch.