Category: Space Shuttle

Investigators working on the Columbia accident said this week that the launch photos from a key camera were too blurry to provide useful images. Sharper images of foam falling from the external tank and crashing into the wing might have given NASA more reason to take the situation seriously. The investigators recommended that NASA upgrade its camera systems for future launches, and consider additional views from airplanes and ships.

The Columbia Accident Investigation Board announced today that the foam theory was the “most probable cause” of the space shuttle tragedy. Based on analysis from tons of Columbia debris, they believe there is compelling evidence that a large chunk of foam fell off the fuel tank on launch and cracked a critical heat shield on the shuttle’s wing. Upon re-entry several days later, hot air flowed inside the wing and melted metal braces, and eventually tore the wing off – the entire shuttle came apart moments after that. The investigators are working on their final report, which is due in July.

Although NASA has made tentative plans to launch the space shuttle Atlantis some time near the end of 2003, it’s more likely to happen in early 2004. NASA is expected to announce the launch date in about six weeks. Although all the technical fixes can be made by December, one of the new regulations is that the shuttle will need to launch only in the daytime, so any problems during launch can be spotted from the ground – but there are only two daylight launch windows available in December. All shuttle flights were halted when Columbia broke up over Texas in February, 2003.

Shuttle investigators have found another potential problem that could damage future space shuttles during launch. When searching through radar data of the Columbia, the investigation board discovered that an 18 kilogram bolt connecting the shuttles boosters to its fuel tank flew off . There’s no evidence that it actually hit the shuttle, but its potential damage to future missions could be catastrophic. Fragments of the bolt are supposed to be caught in a special cylinder to prevent exactly this kind of problem, but it appears that the capture device needs improvements.

NASA is indicating that a new regime of inspections will be required for its fleet of space shuttle to start flying again. In the case of Columbia, it’s believed that a hairline crack only a few centimeters long was created when a chunk of foam from its fuel tank smashed into its wing. NASA administrator Sean O’Keefe said that it’s going to take an “extremely meticulous” inspection system to catch this kind of problem for future flights. When launches do resume, they will be daytime flights only, so cameras can monitor the shuttle’s flight to orbit. The shuttle may return to flight in December or some time in 2004.

As predicted earlier in the week by Columbia accident investigators when a chunk of foam was fired at an actual space shuttle wing, it caused visible and significant damage. The foam was fired from a special pressurized gun at 234 metres per second, and when it struck the wing, it created a 7.5 centimetre crack in the carbon-fiber wing, and damaged several important T-seals. The test wing had actually been flown on space for 30 missions, so the experiment provided useful evidence to support the theory that foam damaged Columbia’s wing so that the shuttle couldn’t survive re-entry.

An initial foam impact test on a section of an orbiter reinforced carbon-carbon left-wing leading edge showed visible and significant damage on RCC panel 6 and the T-seal between RCC panels 6 and 7, the Columbia Accident Investigation Board reported today.

The foam-strike was part of a series of tests the CAIB is conducting at Southwest Research Institute to determine how a foam strike of the kind observed on Columbia’s launch might damage the RCC panels, T-seals, or their support structure. The tests were designed to bracket the observed impact region and conditions.

In today’s outdoor test, investigators fired a large block of foam from a pressurized nitrogen gun aimed at the lower side of left-wing RCC panel 6. The foam struck the panel directly on target and created a three-inch crack extending from a visible three-quarter inch damage area on the outside of the RCC to the RCC rib inside the wing. Later examination revealed that the T-seal between panels 6 and 7 was cracked as well. The strike also caused a shift in the position of RCC panel 6 and the T-seals on either side of that panel, and chipped a carrier panel on the upper side of the wing.

RCC panel 6 was an actual panel that flew 30 missions on Discovery, another Orbiter.

Foam details:

Weight: 1.68 lbs.
Dimensions: 21 3/8 inches x 11 9/16 inches x 5 5/8 inches
Volume: 1,390 cubic inches
Speed: 768 feet per second
Angle of incident: 20 degrees

The CAIB has not reached any final conclusions and has not determined the cause of the loss of the shuttle and crew. The board’s final report will be issued later this summer.

Original Source: CAIB News Release

Thunderstorms in Texas have forced investigators to push back a crucial test to determine if foam could actually cause the damage that destroyed the space shuttle Columbia in February. On this next test, they will fire a chunk of foam at a real shuttle wing, donated by the space shuttle Discovery. Investigators didn’t want to risk getting their camera equipment wet from the driving rain, so they decided it was best to push the test back.

The accident investigator searching for the cause of the Columbia disaster said he was surprised by the force that foam tearing off of the shuttle’s fuel tank could cause to its wing. In a recent experiment, investigators fired a 760 gram chunk of foam at a fiberglass replica of the shuttle’s wing and tore open an important seal. Even more damage is expected when the next round of tests are performed with real shuttle wing parts, removed from Discovery, which are composed of reinforced carbon.

The Columbia disaster investigators believe they might have better proof that foam could have damaged the shuttle’s wing on launch. They recreated the conditions of launch, and fired a 760 gram chunk of space shuttle foam at the leading edge of a shuttle wing at 855 kph. On their first and only shot, they were able to lift up a seal, creating a gap 55 centimetres long. This gives further support to the theory that foam caused damage to the wing on launch, so that it couldn’t withstand the heat of re-entry. Further tests are planned for June.

The group investigating the cause the space shuttle Columbia disaster held a press conference on Wednesday where they presented some new recommendations for NASA. One possibility is for NASA to make a demonstration flight of the shuttle before full-scale missions resume. The first four shuttle flights were considered test flights, where there were only two pilots equipped with ejection seats. The 13-member team will start writing its thick report, which should be finished in July.