Last year offered a mixed bag for spaceflight aficionados. The highs were very high, with SpaceX flying, landing, and reflying rockets at an unprecedented rate while finally beginning to deliver on its considerable promise. But the lows were pronounced too, with the loss of the Cassini spacecraft in the outer Solar System and NASA's continued lack (for nearly a full year) of an administrator.
There were also delays upon delays. The ultra-expensive James Webb Space Telescope saw its launch date slip from 2018 into sometime in 2019. NASA's Space Launch System rocket saw its maiden launch slip from late 2018 into 2019 and then again into 2020. The Falcon Heavy also moved to the right on the calendar, from November, then December, and finally into early 2018.
But all of those delays mean that the last couple of years of the 2010s should feature a lot of spaceflight action, and a good chunk of that will occur in the next 12 months. Looking ahead at what is to come, here are the key spaceflight milestones we're most eager to see in 2018, grouped by the approximate quarter of the year in which they might happen.