A previous SpaceX Dragon cargo capsule sits on the launch pad in Florida before heading to the space station.

NASA and SpaceX have postponed the planned launch of a new Dragon cargo ship this week due to a power system glitch on the International Space Station, agency officials said today (May 1).

SpaceX will now aim to launch the Dragon resupply mission atop a Falcon 9 rocket no earlier than Friday (May 3), a two-day delay, NASA officials added.

The launch delay came at NASA's request as engineers on Earth tackle a power issue on the station that began on Monday (April 29), when a problem popped up with one of the station's Main Bus Switching Units. The device distributes electricity for two of eight power channels on the station.

"There are no immediate concerns for the crew or the station," NASA officials said in the statement today (April 30). "Teams are working on a plan to robotically replace the failed unit and restore full power to the station system."

Related: How SpaceX's Dragon Space Capsule Works (Infographic)

The power issue isn't a concern for the six astronauts currently living and working on the space station , but it has affected the outpost's Canadarm2 robotic arm, NASA officials said.

NASA spokesperson Dan Huot told Space.com Monday that the power issue affected one of two power systems on the robotic arm, leaving it without a backup. The Canadarm2 robot arm is vital to SpaceX's Dragon mission, since astronauts will use the appendage to capture Dragon when it arrives at the orbiting lab. The arm is also used to attach Dragon to the station.

.@NASA has requested @SpaceX move off from May 1 to no earlier than May 3 for the launch of its #Dragon cargo mission to the station. https://t.co/inTfUoHT30 pic.twitter.com/3m3lchffdXApril 30, 2019

A pair of astronauts worked on the robotic arm's power supply during a spacewalk conducted earlier this month , but that work focused on jumper cables along the arm's length. The current problem, instead, is with the station equivalent of a circuit-breaker.

"Flight controllers have been working to route power through the remaining six power channels," NASA officials said in a statement released yesterday .

The launch has already been hit by two delays , which pushed the launch first from April 26 to April 30 on account of "station and orbital mechanics constraints," then to May 1. The rocket will lift off from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida.

When it does launch, the capsule will set off on a leisurely three-day journey to the space station, where astronauts will unpack the more than 5,550 lbs. (2,495 kilograms) of supplies it carried. That includes fresh supplies and new science experiments.

The mission, called CRS-17, will be SpaceX's 17th cargo delivery flight for NASA under a resupply contract.

Space.com managing editor Tariq Malik contributed to this report.