Cartridge Seal

new hypotheses offered at shuttle inquiry

by:Lepu     2019-11-14
By WILLIAM J.
For the New York Times 1986, this is a digital version of an article in The Times Print File, before it begins online publishing in 1996.
To keep these articles as they appear initially, the Times will not change, edit, or update them.
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Space agency officials today revealed a series of problems with the Challenger shuttle boosting the rocket before its launch, giving a more detailed account of what happened before the spacecraft exploded, and put forward some new assumptions about the cause of the disaster.
According to the new theory, ice or bad seals between booster rocket joints may lead to the challenger\'s explosion, resulting in the death of all seven crew members.
At a public hearing at the Kennedy Space Center, members of the presidential commission investigating the accident expressed doubts about the new assumptions.
So far, the panel appears to be sympathetic to the testimony of the contractor\'s engineers, who say it was too cold on the morning of January.
28 for proper operation of key booster seals.
William P. , chairman of the committee.
Rogers has come up with some new theories that are self-possibilities.
Service and advise engineers outside the Marshall Space Flight Center of Ala Huntsville to carry out some experiments to test their effectiveness.
This is the driving force behind them.
The advertisement is also today, NASA engineers conducted a detailed \"fault analysis\" of the possible causes of the explosion, and initially ruled out several reasons, including the problems of the orbiter itself, its main engine and its satellite-powered rocket in the space shuttle payload compartment.
The ad\'s new insight into the Challenger\'s last moments comes from linking photos to data sent back to Earth from ships destined to fail.
The photos, taken in 64 seconds after the shuttle flew nearly 74 seconds, show a change in the flame feather extending from the shuttle\'s right booster, which is related to the disaster. Thomas L.
Moser, deputy director of the space shuttle program, testified today that new data show that there is \"strong\" evidence that, the flame of the booster rocket caused a hydrogen leak in the shuttle\'s huge external fuel tank.
He said that about two seconds after the plume changed shape, pressure drop was measured in the hydrogen fuel tank.
NASA officials also said the data showed the bottom of the solid
The fuel booster rocket apparently broke out of the fuel tank after about 72 seconds of flight, and the top of the booster rotated on the forward connection point, piercing the top of the fuel tank.
This series of events released most of the liquid fuel in the tank.
In addition, the agency officials disclosed today that a key part of the booster rocket was deformed and had to be thrown back into the \"circle\" in a series of unusual steps during the assembly process \".
The solid rocket consists of four main components assembled by contract company Morton tiokor, which makes the rocket, at the Kennedy Space Center.
NASA officials said today that when shipping from a factory in Utah, the parts were on one side and were sometimes forced to leave due to their own weight.
They testified that the lowest part of the challenger\'s right booster is well beyond the round and must be corrected.
The usual error tolerance is a quarter of an hour per inch, and this part is more than doubled in deformation.
What is suspected to fail in the Challenger disaster is the seal between the bottom and the next part.
The tool used to realign to correct the problem, the defective bottom part hangs from the crane at two unbalanced points so that its own weight can realign it.
It helps, officials say, but its size is still unacceptable.
The advertisement therefore, according to Robert Lang, director of the department of mechanical systems for shuttle operations at Kennedy Space Center, the technician used a tool that had been used six times before.
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This tool is a movable rod that is mounted at the end of the booster section and activated by a hydraulic hand pump. Mr.
Lang said that this exerted about 3,000 pounds force on the edge of the booster segment.
According to Carver Kennedy, operations manager of Morton tiokor at Kennedy Space Center, the tool was developed because sometimes in order to restore shape, segments had to hang \"one day\" from the crane \".
Jerrol Wayne Littles, deputy director of Marshall Engineering, said that due to some pain and pull, during the mating process of the fragments, \"it is possible to cause O-ring damage \".
The engineer testified today that the seal could be defective and damaged the rocket parts during processing on November.
This is an isolated incident.
Bill Barras, engineering manager, Kennedy Space Center, Lockheed Space Operations, said he was \"very confident\" and that the new procedures developed after the accident ensured that the challenger\'s booster had no similar problems, all of this was assembled after the accident in November.
The most interesting new suspect as the cause of the explosion is a flaw in one of the seals on the booster rocket in a photo published today.
Photos submitted by Mr. Today
Litthiokol technicians use Littles as part of the regular \"finishing\" procedure in Challenger rocket assembly. The rubbery 12-
Foot seals known as O-rings are designed to make Air
Tight closure between booster rocket segments.
But the Marshall engineer testified that the tiny O-ring defects that are hard to see in the photos could cause hot gas and flame leaks.
When asked if a black cigarette observed in a photo of a few seconds after the Challenger took off was related to a possible defect, Sir
Little replied that it was \"realistic \".
However, he noted that these gases need to be migrated from approximately 90 degrees at the site of the obvious problem to the outside area of the booster observed to the black smoke plume.
The last new suspect in the ice trapped together is ice, and when the challenger sits on the launch pad for 37 days, in the rain and unusually cold weather, ice may be trapped in the booster
This paper argues that the ice that expands in the joint will unlock the critical O-ring.
The ads say ice may also cause a stream of steam, and officials at the Marshall Space Flight Center say they can see it in the photos.
But the panelists questioned whether this \"white\" smoke was really visible and suggested that the test of the ice theory be supervised by external engineers.
Today, with respect to the O-ring, sir.
Littles revealed that the inspection procedure changed before getting sick
Some steps were missed due to negligence.
Obviously downplaying this observation, major. Gen. Donald J.
Kutyna, a member of the Commission, the Air Force, noted that only the back-up inspection had been abandoned and a major inspection had been retained.
A version of this article appears on page 1001001 of the national edition of March 8, 1986, titled: new assumptions provided by the space shuttle survey.
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