While NASA pushes it Space Launch System (SLS) to make a mid-2020 debut, Orion also needs to find solutions to both match the realigned targets and achieve key objectives before the second flight with astronauts onboard.
Most notably, the Orion Environmental Control and Life Support System (ECLSS) is set to make its full debut on the first crewed mission, requiring the spacecraft to loiter in Low Earth Orbit (LEO) – before heading to the Moon – to allow for a speedy abort should issues be found in the system. Various test opportunities, including on the ISS, are being called upon to mitigate potential issues.