If the rocket isn’t ready at that time—SpaceX said it is assessing a single thermal protection panel on the Dragon spacecraft as a potential risk to the mission—the company plans to try again on July 1. The mission will carry 5,900 lbs (2,676 kg) of science experiments, food, water, and other gear to the six astronauts currently living on the orbiting lab.

This will be SpaceX’s 12th launch this year, and the ninth time a mission has used a flight-proven booster. According to Jessica Jensen, the SpaceX executive in charge of the company’s Dragon spacecraft, reusability has allowed the company to increase its cadence to launch, on average, every two weeks. Next month, the company is scheduled to fly two different satellite launch missions in a two-day period.

Time for human spaceflight

SpaceX, along with rival Boeing, is also coming under pressure to begin flying astronauts to the ISS. Both companies are building spacecraft expected to carry the first people into orbit from US soil since 2011, but have faced delays in meeting NASA’s tough safety requirements. NASA maintains that un-crewed test flights will happen this summer and fall, with crewed flights in December, despite widespread expectations outside the agency that delays are likely.

“NASA keeps referring to August as the date, and everyone in this room knows that’s not going to happen,” veteran CBS News space reporter Bill Harwood insisted during a tense moment at a pre-flight press conference at Kennedy Space Center in Florida.

Kirk Shireman, NASA’s manager of the ISS, replied that it wasn’t so simple: The companies work to prepare their vehicles for the targeted date, then the space-station program must mix in the test missions alongside regular flights and activities. Jensen noted that SpaceX’s vehicle was currently at a NASA test site in Ohio, where it will undergo a battery of pre-flight vacuum tests before heading to Kennedy to prep for an August test flight.

One key component of that mission will be the new Block 5 Falcon 9 rocket, which is designed to meet human spaceflight requirements. Though a version of the rocket flew for the first time in May, Quartz revealed that it did not include critical upgrades designed to prevent catastrophic failures. Those upgrades are also expected to be ready for the un-crewed demonstration meeting.

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