FighterJock said:
Two years until the first SLS launches, I wonder what the hold up is? Hope it is nothing major.
NASA aim for 2019 launch, but is not sure even about that !
Some of delay in short form
The NASA plant in New Orleans was hit by storm and was Damage, during repairs on building, work on SLS core was interrupted.
They redo welding on the core stage after inspection revealed low weld strengths.
If the Core can be deliver to KSC for testing in September 2017 is questionable
Orion capsule has delays because modification to systems and Heat shield after December 2014 test flight.
Airbus again has delays in Orion Service Module (former ATV) do underestimating the time and effort necessary to adapt the design.
Airbus will deliver Orion Service Module only in August 2017 to Lockheed facility
what make Orion ready for KSC transport not before August 2018 and delaying launch readiness testing to be ready in November 2018.
Next to that has Lockheed issue with some hardware and the Software on Orion spacecraft.
Missing needed Spacesuits for Orion Spacecraft.
after spending 200 million dollar on Space suits R&D NASA has no space suit ready for Orion spacecraft.
all they got are 18 old Shuttle spacesuits were 11 are operational and they usable for Orion spacecraft
the JSC space suits will be not ready before 2020 or 2024.
One moment why i mention spacesuits for EM-1 flight ?
now at NASA some in Administration proposed to make 2019 EM-1 a Manned Flight !
Source
new schedule 2019
http://spacenews.com/nasa-plans-to-delay-first-slsorion-mission-to-2019/
Space Suits issues
https://www.seeker.com/space/exploration/nasas-200m-spacesuit-problem-threatens-its-deep-space-exploration-plans
EM-1 manned
http://www.popularmechanics.com/space/rockets/a25232/nasa-considers-astronauts-sls-launch/