SN10 takes flight. SN15 features several upgrades over its predecessors.SpaceXAfter four successful test flights of SpaceX's next-generation Starship prototypes all ended in dramatic explosions during the landing phase, Elon's Musk's space company is skipping ahead to SN15, a new version of its interplanetary rocket. SpaceX has conducted high-altitude test flights of prototypes SN8 through SN11 and has long planned to integrate what Musk has called "major upgrades" into SN15. Now the company is skipping SN12, SN13 and SN14, which were never fully assembled, and working toward a flight of SN15 as soon as this week. SN15 rolls to launch pad in a few days. It has hundreds of design improvements across structures, avionics/software & engine. Hopefully, one of those improvements covers this problem. If not, then retrofit will add a few more days. Elon Musk (@elonmusk) March 30, 2021Musk has said SN15 "has hundreds of design improvements across structures, avionics/software and engine," including, hopefully, upgrades to cover some of the problems that've prevented SpaceX from sticking the landing so far without a rapid unscheduled disassembly. SN15 has undergone some initial testing, and Musk initially tweeted that the aim was to launch last week, but that target continued to slip, and current airspace closures indicate Wednesday is the soonest we'll see it fly. A key static test fire took place Monday and Musk confirmed the goal is get off the ground this week.Starship SN15 static fire completed, preparing for flight later this week Elon Musk (@elonmusk) April 27, 2021SN15 could launch anytime (or not at all) within the approved windows once all the required closures and permissions are in place. We usually don't have any firm sense of when it'll blast off until less than an hour before liftoff appears set to happen (even then, false starts are common). So for now, keep your fingers crossed that we see SN15 fly (and land!) this month. We'll post a live feed of the launch right here once it's available. We'll update this post at least daily as things change, and for more-incremental updates, tune in to my Twitter feed @EricCMack. Follow CNET's 2021 Space Calendar to stay up to date with all the latest space news this year. You can even add it to your own Google Calendar.