"The Block 1 SLS is the 'basic model,' sporting a Delta Cryogenic Second Stage (DCSS), renamed the Interim Cryogenic Propulsion System (ICPS) for SLS. The current plan calls for this [interim] stage to be used on [the unmanned] Exploration Mission -1 (EM-1) and [manned] Exploration Mission -2 (EM-2), prior to moving to the [Exploration Upper Stage] — also to be built by Boeing — that will become the workhorse for SLS. However, using the [interim upper stage] on a crewed mission will require it to be human rated. It is likely NASA will also need to fly the [Exploration Upper Stage] on an unmanned mission to validate the new stage ahead of human missions. This has been presenting NASA with a headache for some time, although it took the recent ASAP meeting to finally confirm those concerns to the public."
NASA doesn't have the funds to human-rate it, and even if they get those funds, human-rating it will likely cause SLS's schedule to slip even more, something NASA fears because they expect the commercial manned ships to be flying sooner and with increasing capability. The contrast — a delayed and unflown and very expensive SLS vs a flying and inexpensive commercial effort — will not do SLS good politically. However, if they are going to insist (properly I think) that SpaceX and Boeing human-rate their capsules and rockets, then NASA is going to have to hold the SLS to the same standard.
If a large NEO were to hit Earth, the report said, its denizens could look forward to acid rain, firestorms, and an impact winter induced by dust being thrown miles into the stratosphere. ... After reports from the National Research Council made it clear that meeting the discovery requirement outlined in the Congressional mandate was impossible given the lack of program funding, NEOO got a tenfold budget increase from 2009 to 2014. Yet it still faces a number of difficulties. A program audit released last September described the NEOO program as a one-man operation that is poorly integrated and lacking in objectives and oversight.
Elon Musk has posted a note on the company's Twitter channel: "Falcon 9 experienced a problem shortly before first stage shutdown. Will provide more info as soon as we review the data."