SpaceX Crew Dragon test flights delayed
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An artist’s rendering of a Crew Dragon on final approach to dock with the International Space Station. Image Credit: SpaceX
In a revised schedule released by NASA on Dec. 12, 2016, it was revealed that SpaceX has delayed test flights for its Crew Dragon spacecraft by a number of months. According to Space News, this is, at least in part, due to the Sept. 1 Falcon 9 pad explosion.
The NASA statement gave no reason for the delays other than it reflected a “fourth quarter update” from both SpaceX as well as the Boeing dates that were revised in October 2016.
Before the release, SpaceX was still targeting a May 2017 uncrewed test flight and a crewed flight in August 2017. However, that has been pushed to November 2017 and May 2018, respectively.
SpaceX is still investigating the exact cause of the September 1 explosion. During the lead up to the prerequisite static test fire for the the $195 million Amos 6 satellite, the rocket and satellite were lost in the resulting fireball.
The company was hoping to return to flight as early as this week; however, last week, it was revealed the company needed more time to finalize their findings. Currently, the first flight is scheduled for early January 2017. That flight is expected to send 10 Iridium NEXT satellites into orbit from Vandenberg Air Force Base in California.
Additionally, at an Oct. 31 meeting of NASA’s International Space Station Advisory Committee, Chairman Thomas Stafford, a former Apollo astronaut, criticized SpaceX’s plan to have astronauts aboard the Crew Dragon during the Falcon 9’s unconventional fueling process.
In order to get the most performance out of the Falcon 9 and its nine Merlin engines, the company fuels the rocket with “supercooled” propellants some 30 minutes before launch. The fuel and oxidizer – rocket grade kerosene and liquid oxygen, respectively – are chilled to near their respective freezing points, densifying them.
Stafford said that the plan to have people aboard the rocket during this process would be “contrary to booster safety criteria that [have] been in place for over 50 years”.
It is currently believed, by SpaceX, that the Sept. 1 pad explosion was due, in part, to the supercooled fueling process. While the company hasn’t said they found an exact cause, it has narrowed it down to one of the three composite overwrapped pressure vessels inside the upper stage’s liquid oxygen tank.
The current thinking is that, during the loading process, some of the oxygen got so cold that it actually entered into a solid phase, which isn’t supposed to happen. According to The Verge, this solid oxygen may have had a bad reaction with the carbon on the helium-filled COPVs, causing the explosion.
SpaceX said that the company has offered the committee a detailed approach and answers to a number of questions; however, it is unknown what response, if any, Stafford and his committee have given.
Either way, the new schedule now gives even less margin to NASA for certifying SpaceX’s Crew Dragon and Boeing’s CST-100 Starliner. The U.S. space agency’s contract with Russia for Soyuz flights to the International Space Station ends at the close of 2018.
NASA currently has no plans to extend the contract. Even if they wanted to, it’s likely the agency has crossed the deadline to order more Soyuz flights for 2019, as it usually requires about three years to procure a new Soyuz.
NOTE: While this article was written by Derek Richardson, it was originally published at SpaceFlight Insider. Feel free to head over there to read all the stuff they write about!
