Godspeed, S.S. John Glenn.

An unmanned cargo ship named in honor of the pioneering American astronaut is on its way to the International Space Station after launching from Cape Canaveral atop a modern version of the Atlas rocket Glenn rode into orbit in 1962.

United Launch Alliance’s 19-story Atlas V thundered from Cape Canaveral Air Force Station’s Launch Complex 41 at 11:11 a.m. Tuesday, flying through a few puffy clouds on a northeasterly trajectory over the Atlantic Ocean.

Twenty-one minutes later, an Orbital ATK Cygnus craft packed with more than 7,600 pounds of food, supplies and experiments separated from the rocket’s Centaur upper stage.

“It was a beautiful launch,” said Vern Thorp, ULA’s program manager for commercial missions. “Looks like we nailed the orbit again.”

Rendezvous at the research outpost orbiting 250 miles overhead is planned Saturday morning, following Thursday’s scheduled launch from Kazakhstan by a NASA astronaut and Russian cosmonaut who will join three Expedition 51 crew members.

Research aboard the Cygnus includes a minifridge-sized plant growth chamber, a student experiment amplifying DNA to look at changes in the aging process, and a company’s test of a chemotherapy drug that could better cancer cells.

Other equipment includes gear needed for an upcoming spacewalk, and 38 tiny satellites called “CubeSats” that will be deployed from either the station or Cygnus.

Also on board: Easter baskets.

The mission originally was scheduled to launch about a month ago, but problems with hydraulic systems on the ground and on the rocket’s Russian RD-180 main engine caused delays.

“The crew, of course, is always very anxious to see what comes up in the Cygnus spacecraft,” said Frank Culbertson, a former station astronaut who leads Orbital ATK’s Space Systems Group. “We are sorry we missed Easter, but we’re pretty sure they’ll be excited about their Easter baskets, and whatever great things International Space Station science put on board for them.”

Orbital ATK names each Cygnus craft to pay tribute to influential astronauts.

Glenn, the former U.S. senator who died last December at 95, inspired multiple generations when he became the first American in orbit at the dawn of the Space Race with the Soviet Union, and later the oldest person in space as a 77-year-old crew member aboard the shuttle Discovery in 1998.

“It’s a great tribute to John to be able to take his name to orbit once again,” said Culbertson. “I’m sad that he’s gone, but he’s lived a really full life, and he’s provided inspiration to a couple of generations of American men and women.”

The Cygnus carried some mementos for the Glenn family, who could not attend the launch due to its delays.

Tuesday’s launch was the seventh of a Cygnus under a NASA Commercial Resupply Services worth up to $3.1 billion. It was third of those launched by ULA’s Atlas V, which can lift heavier loads than Orbital ATK’s own Antares rocket based on Virginia’s Eastern Shore.

ULA has now completed four launches this year. Its next is not expected before early August.

SpaceX is next up on the Eastern Range. A Falcon 9 rocket is targeting an April 30 launch of a classified National Reconnaissance Office mission from Kennedy Space Center’s pad 39A, and a booster landing back at Cape Canaveral Air Force Station.

Contact Dean at 321-242-3668 or jdean@floridatoday.com. Follow him on Twitter at @flatoday_jdean.