changes in rocket strained booster\'s seals, experts say
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Due to the changes in the booster structure ordered by NASA in 1983, the key points of the shuttle booster rocket are under increasing pressure, according to public documents and former officials of the space agency.
Structural changes allow the shuttle to lift heavier payload into space at a lower cost, including the use of thinner shells on boosters, each of which is 4,000 pounds lighter, at the same time make the supercharged engine more powerful.
Aerospace experts said today that these changes have put more pressure on the joints between booster rocket segments, which have a history of problems. \"With high
A former NASA official at the Kennedy Space Center said that you have more pressure, heat and pressure on the performance motor.
\"The agency should look at what this has to do with the entire space shuttle system, but somehow they missed it.
He added: \"advertising\" nasa is known for its systems engineering.
But somehow, it happened.
Charles Redmond, a spokesman for NASA\'s Washington headquarters, did not comment, saying: \"This is exactly what the presidential commission is going to consider.
The space agency speculated that these things were wrong.
\"Nasa officials say they know there is a problem with these joints, but they don\'t think it will threaten the safety of the shuttle.
The joints connecting the four main booster sections are sealed by a set of rubber rings designed to limit the hot gas and flame inside the supercharger housing.
The booster joint has long been considered one of the most vulnerable parts of the rocket propulsion system, and investigators are investigating the fiery destruction of the Challenger shuttle in January.
28 It has been said that the fracture of the joint is one of the main theories leading to the explosion, which killed all seven astronauts on board.
The decision to use a higher-powered rocket was made at a time when space agency officials abandoned the shuttle safety standards for the booster joint.
Still, the agency is sticking to the joint design and plans to continue using the new engine.
The presidential commission investigating the Challenger disaster made public the past issues of the joint documents last week, indicating concerns about the joint documents and linking their problems to a stronger engine.
Frequency of O
A report submitted at NASA headquarters on August noted that ring damage has increased since the inclusion of high-performance motors.
1985, officer of Morton tiokor
Design and build booster rockets and Marshall Space Flight Center in Huntsville, Alabama.
Responsible for overseeing NASA\'s work on space shuttle engines.
The O-ring is basically a big donut.
A synthetic rubber molding piece filled with a tiny gap of the cylindrical booster section bolts attached together, much like the rubber gasket on the faucet.
The ring itself can prevent heat and flame damage through the initial barrier of putty.
However, 1982 of the ads show that NASA knows that O-rings and their associated structures do not work as designed.
According to a memo from the 1982 Space Agency, the issue dates back to \"a phenomenon called joint rotation \".
The dangerous rotation of the rotational force occurs because the explosive energy inside the rocket forces the relatively thin steel skin of the booster section to outward.
Since the joint between segments is made of a thicker metal, this outward movement can be resisted.
The result is that the rotation between joint elements is very small.
The danger is that the rotation can unlock the O-ring within seconds of takeoff and create a slight gap on the side of the booster, allowing the heat and flame to escape.
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Public photos of the space agency show challenger rights.
The side booster is obviously leaking this way.
According to space agency officials, the O-ring problem became worse after turning to light in 1983 --
Weight steel housing and motor with higher power.
Lightweight solid housing-
The fuel-boosting rocket was first used in the sixth space shuttle mission in April 1983.
According to documents released by Rockwell International, the main manufacturer of the shuttle, each of the two boosters of the shuttle was shaved off two, 4,000 pounds lighterto four-
Steel case of 1 inch.
This reduction is equivalent to 2% of the total mass of the booster metal parts.
Starting with the eighth shuttle flight in August 1983, a new, more powered booster engine was used.
The thrust increased by about 5%, according to Rockwell documents.
Power is gained by reducing the outlet nozzle of the booster and making the fuel burn faster.
A document submitted to the Presidential Commission mentions the engine link Lawrence B.
Mulloy, project manager at Solid-
The fuel-boosting rocket at the Marshall Space Flight Center pointed out that O-
After the launch of the new engine, signs of ring damage, wear and problems have increased.
He said only one flight had a problem before the new engine appeared, but then there were six problems.
A possible cause of the problem, former NASA officials said today, is that the thinner shell of the booster rocket will bear more pressure to generate more rotation at the joint of the booster, increased the possibility of O-rings being untied and damaged by flames.
\"As the pressure increases, they can open wider,\" he said . \".
This is almost a linear function.
He added that another factor could be the effect of higher temperatures and pressures on Putty designed to protect O-rings in the new engine.
An engineer at Morton Thiokol, Brigham, Utah, said today that the company tested the joint rotation before and after the introduction of a higher-powered engine and found no significant increase in rotation.
\"There is nothing different,\" the engineer said, on the condition that he was not identified.
He added that he could not publish the details of the test.
Another possible factor was mentioned in NASA\'s August document.
1985, announced by the presidential commission.
The engineer suggested that a new type of putty failed to properly protect the O-ring.
Engineers recommend finding another putty in the short term. As a long-
Term solution, they recommend creating a new booster housing with a \"capture function\" to reduce joint rotation by holding down the inner flange supporting the O-ring.
Engineer Morton Thiokol, in a document dated August.
On the 26 th, 1985, and released by the Presidential Commission last week, 43 different approaches were listed to deal with the issues raised by O ring.
All of the proposed solutions do not involve new types of putty.
Instead, the vast majority of the 43 solutions require new O-rings and new booster housing to reduce joint rotation.
Experts say a version of the article appeared on page A00014 of the National edition in February 17, 1986, with the title: a change in the rocket\'s nervous booster seal.