NASA has announced that the first two missions of its Orion deep-space capsule will most likely be delayed. The spacecraft is being developed to send human astronauts outside of the Earth's orbit and onwards to Mars.

The space agency's Office of Inspector General (OIG) admitted that technical and budget difficulties are the probable causes of the delay. The first launch of the Orion spacecraft which will be placed on top of the planned Space Launch System (SLS) has been previously scheduled for Nov. 2018 with no crew.

Its second mission will carry human astronauts. It is initially scheduled for Aug. 2021.

The European Space Agency (ESA) has confirmed that it will be helping NASA for the manned Orion mission planned for 2021. It will be contributing key components for the Orion mission.

The mission will include up to four astronauts. Crew size and composition will be confirmed closer to launch.

With the mission, Orion will follow three progressively elongated orbits to reach past the moon and return to Earth. This is believed to be faster than the speed by which any manned spacecraft has reentered the atmosphere ever.

Phys.org reported that the Orion missions face "multiple cost and technical challenges" which is expected to affect their planned launch dates. The statement of NASA's Office of Inspector General noted the source of the causes as from the delays in the development of the service module, provided by ESA, and technical risks from design changes of the capsule's heat shield.

According to The Verge, the space agency is working on all the hardware on necessary on the ground to support the launches. It includes building a new mobile launch platform for the SLS to take off from as well as making changes to some buildings at NASA"s Kennedy Space Center in Cape Canaveral, Florida.

Space News added that the OIG also asked the agency to provide more details on its future missions. More information on technology requirements needed to enable the long-term goal of human missions to the surface of Mars is also needed.