a new satellite constellation, called Starlink, to provide global broadband internet service with 4,000 satellites. The Falcon 9 had its first major failure in late June 2015, when the seventh ISS resupply mission, CRS-7 exploded two minutes into the flight. The problem was traced to a failed 2-foot-long steel strut that held a helium pressure vessel, which broke free due to the force of acceleration. This caused a breach and allowed high-pressure helium to escape into the low-pressure propellant tank, causing the failure. 2015–2017: Reusability milestones SpaceX first achieved a successful landing and recovery of a first stage in December 2015 with Falcon 9 Flight 20. In April 2016, the company achieved the first successful landing on the autonomous spaceport drone ship (ASDS) Of Course I Still Love You in the Atlantic Ocean. By October 2016, following the successful landings, SpaceX indicated they were offering their customers a 10% price discount if they choose to fly their payload on a reused Falcon 9 first stage. A second major rocket failure happened in early September 2016, when a Falcon 9 exploded during a propellant fill operation for a standard pre-launch static fire test. The payload, the AMOS-6 communications satellite valued at US$200 million, was destroyed. The explosion was caused by the liquid oxygen that is used as propellant turning so cold that it solidified and ignited with carbon composite helium vessels. Though not considered an unsuccessful flight, the rocket explosion sent the company into a four-month launch hiatus while it worked out what went wrong. SpaceX returned to flight in January 2017. Later that year, in March 2017, SpaceX launched a returned Falcon 9 for the SES-10 satellite. This was the first time a re-launch of a payload-carrying orbital rocket went back to space. The first stage was recovered again, also making it the first landing of a reused orbital class rocket. 2017–2018: Leading global commercial launch provider In July 2017, the company raised US$350 million, which raised its valuation to US$21 billion. In 2017, SpaceX achieved a 45% global market share for awarded commercial launch contracts. By March 2018, SpaceX had more than 100 launches on its manifest representing about US$12 billion in contract revenue. The contracts included both commercial and government (NASA/DOD) customers. This made SpaceX the leading global commercial launch provider measured by manifested launches. In 2017, SpaceX formed a subsidiary, The Boring Company, and began work to