Disintegration of the SpaceX CRS-7 launch vehicle approximately two minutes after liftoff as seen from a NASA tracking camera.
|Mission type||ISS resupply|
|Mission duration||Planned: 1 month |
Final: 2 minutes, 19 seconds
|Spacecraft type||Dragon CRS|
|Start of mission|
|Launch date||June 28, 2015, 14:21:11UTC|
|Rocket||Falcon 9 v1.1|
|Launch site||Cape Canaveral SLC-40|
|End of mission|
|Disposal||Destroyed on launch|
|Destroyed||June 28, 2015, 14:23:30UTC|
NASA SpX-7 mission patch
SpaceX CRS-7, also known as SpX-7, was a private American Commercial Resupply Service mission to the International Space Station, contracted to NASA, which launched and failed on June 28, 2015. It disintegrated 139 seconds into the flight after launch from Cape Canaveral, just before the first stage was to separate from the second stage. It was the ninth flight for SpaceX's uncrewed Dragon cargo spacecraft and the seventh SpaceX operational mission contracted to NASA under a Commercial Resupply Services contract. The vehicle launched on a Falcon 9 v1.1 launch vehicle. It was the nineteenth overall flight for the Falcon 9 and the fourteenth flight for the substantially upgraded Falcon 9 v1.1.
In January 2015, the launch was tentatively scheduled by NASA for no earlier than June 13, 2015. This was adjusted to June 22, 2015, then moved forward to June 19, 2015 and adjusted again to June 26, 2015. Subsequently, the launch had been rescheduled to June 28, 2015 at 14:21:11 UTC, from Cape Canaveral LC-40. The launch was scheduled to be the third controlled-descent and landing test for the Falcon 9's first stage. It would have attempted to land on a new autonomous drone ship named Of Course I Still Love You – named after a ship in the novel The Player of Games by Iain M. Banks. The spacecraft was planned to stay in orbit for five weeks before returning to Earth with approximately 1,400 pounds (640 kg) of supplies and waste.
Performance was nominal until 139 seconds into launch when a cloud of white vapor appeared, followed by a rapid loss of pressure in the liquid oxygen tank of the Falcon 9's second stage. The booster continued on its trajectory until the vehicle completely broke up several seconds later. The Dragon CRS-7 capsule was ejected from the exploding launch vehicle and continued transmitting data until it impacted with the ocean. SpaceX officials stated that it could have been recovered if the parachutes had deployed, but the software in the capsule did not include any provisions for parachute deployment in this situation. It is assumed that the capsule crumpled and broke up on impact. Subsequent investigation traced the accident to the failure of a strut that secured a high-pressure helium bottle inside the second stage's liquid-oxygen tank. With the helium pressurization system integrity breached, excess helium quickly flooded the liquid-oxygen tank, causing it to overpressurize and burst. The report from SpaceX pointed out that the stainless-steel eye bolt was rated for a load of 10000 pounds, but failed at 2000 pounds.
An independent investigation by NASA concluded that the most probable cause of the strut failure was a design error: instead of using a stainless-steel eye bolt made of aerospace-grade material, SpaceX chose an industrial-grade material without adequate screening and testing and overlooked the recommended safety margin.
As of July 2013[update], the first International Docking Adapter, IDA-1, was scheduled to be delivered to the International Space Station on CRS-7. This adapter would have been attached to one of the existing Pressurized Mating Adapters (specifically, PMA-2 or PMA-3) and convert the existing APAS-95 docking interface to the new NASA Docking System (NDS). The new adapter is intended to facilitate future docking of new U.S. human-transport spacecraft. Previous United States cargo missions since the retirement of the Space Shuttle have been berthed, rather than docked, while docking is considered the safer and preferred method for spacecraft carrying humans.
A full listing of the cargo aboard the failed mission included the following items:
The mission would have transported more than 4,000 pounds (1,800 kg) of supplies and experiments to the International Space Station including the Meteor Composition Determination investigation which would have observed meteors entering the Earth's atmosphere by taking high resolution photos and videos. The Center for the Advancement of Science in Space had arranged for it to carry more than 30 student research projects to the station including experiments dealing with pollination in microgravity as well as an experiment to evaluate a sunlight blocking form of plastic.
After the second stage separation, SpaceX planned to conduct a flight test and attempt to return the Falcon 9's nearly empty first stage through the atmosphere and land it on autonomous spaceport drone ship Of Course I Still Love You.
This would have been SpaceX's third attempt to land the booster on a floating platform after earlier tests in January 2015 and April 2015 were not successful. The boosters were fitted with a variety of technologies to facilitate the flight test, including grid fins and landing legs to facilitate the post-mission test.