KENNEDY SPACE CENTER, Fla. — SpaceX pushed back its launch of a Falcon 9 rocket to the International Space Station after its drones ship in the Atlantic experienced an electrical issue.

The launch was supposed to happen at 3:11 a.m. ET Friday from Cape Canaveral Air Force Station. There were concerns about the weather, but conditions were decent for the launch early Friday morning.

The problem, however, was with the landing site: SpaceX's drone ship 17 miles off the Atlantic coast, where the company lands the reusable first-stage booster rocket.

SpaceX also said there was a helium leak on the rocket that will have to be addressed.

SpaceX isn't taking any chances after it confirmed Thursday that its Crew Dragon exploded and was destroyed during a test firing almost two weeks ago, sending reddish brown smoke into the air. The Crew Dragon is eventually supposed to transport astronauts.

On Friday's Falcon 9 rocket is a Cargo Dragon, which is different, according to SpaceX and NASA.

"We have looked at all the common links between the spacecraft, we reviewed that and we approved them for flight by both teams, NASA and SpaceX," said Hans Koenigsmann, SpaceX's vice president of mission assurance.

On board the Cargo Dragon capsule is 5,500 pounds of supplies for the ISS, as well as science experiments.

Graduate student Dylan Martin has been preparing her experiment for launch at the Kennedy Space Center's ISS processing facility.

"It's actually really exciting, but really stressful at the same time. We're here long hours, working until late, late in this lab, so it's basically our new home," said Martin, who is a graduate research assistant for BioServe Space Technologists Laboratory at the University of Colorado Boulder.

Her team is trying to figure out how the kidneys and vitamin D work in microgravity to help astronauts avoid bone loss on future long-duration missions in space.

"The crew on the International Space Station experience an increase loss of bone density, and vitamin D is responsible for regulating bone density," said Kendan Jones-Isaac, a graduate research at the University of Washington. "So what we are doing is investigating what causes these health events and how to hopefully screen for or help prevent them or treat them."

After spending years on these projects, the researchers will now have to wait another day to see their experiments go into space.

"It's really exciting. I've always wanted to do that. I'm getting my graduate degree in aerospace engineering, so this is something I've always wanted to do," Martin said.

Saturday's launch is now set for 2:48 a.m. ET. It's also May the Fourth, which Star Wars fans should appreciate for a Falcon 9 rocket launch.