SpaceX CRS-7


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.

Launch history

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 of supplies and waste.

Launch failure

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 which 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 10 000 pounds, but failed at 2 000 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..

Payload

Primary payload

NASA contracted for the CRS-7 mission from SpaceX and therefore determined the primary payload, date/time of launch, and orbital parameters for the Dragon space capsule.
, 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 and convert the existing APAS-95 docking interface to the new NASA Docking System.
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.

Detailed payload manifest

A full listing of the cargo aboard the failed mission included the following items:
The mission would have transported more than 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.
CRS-7 would have brought a pair of modified Microsoft HoloLenses to the International Space Station as part of Project Sidekick.

Planned post-launch flight test

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 a floating platform barge. SpaceX calls the barge an autonomous spaceport drone ship, and this particular mission's ASDS was named 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.