nasa had warning of a disaster risk posed by booster
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Last year, the space agency was warned that the sealing device on the shuttle
According to the agency\'s files, the fuel-boosting rocket could break down and cause catastrophic accidents.
Documents show engineers at NASA headquarters in Huntsville, Alabama and its Marshall Space Flight Center.
, Worried that there may be a leak in the part of the booster rocket.
This leakage will allow the heat and flame to escape from the side of the rocket, rather than discharge the gas from the back through the nozzle, which could cause serious damage or explosion to the shuttle, space experts said.
An analyst at NASA warned in an internal memo on last July that flight safety was \"compromised by a potential seal failure \".
He added: \"The failure in the launch process is certainly disastrous.
The 1982 \"list of key items\" of the booster also warns that if the seal fails, the result may be \"loss of vehicles, tasks and crew due to metal erosion, burn-through\" and burst if possible, cause fire and deflagration, or rapid, intense combustion.
AdvertisementIt is not clear what action NASA may take on the warnings in the document, if any, but this issue was listed as a concern in the agency documents of December.
Space agency officials today declined to answer questions raised in the internal documents.
Two officials were told
Garlitte, head of the agency\'s news and information department, was informed of the substance of the documents and said he had notified L.
Deputy Assistant Administrator for Space Flight Office Michael Chow and David L.
Winterhalter, acting director of the agency\'s Space Shuttle Propulsion department.
They declined to comment, he said. Jesse W.
Moore, the agency\'s top space shuttle official and assistant space flight administrator, did not call his home back, although a family member said he was there.
Internal documents describing the seal issue are provided by the New York Times
Fuel Rocket analysts work closely with propulsion engineers at the Kennedy Space Center in Florida, which has assembled booster rockets;
The Marshall Center in Alabama and NASA Headquarters in Washington are responsible for the design.
Although no one knows exactly what caused the explosion that destroyed the challenger in January, the leading theory.
On the 28 th, space agency officials said that according to the film of the flight, the leading theory, a flame came out from one side of the booster, triggering an explosion in the huge external fuel tank of the shuttle.
Space officials say they cannot accurately identify where the plume appears, so it is not known whether the plume burns through the seam or through the metal side of the rocket.
\"It seems to happen at least near the seams,\" said Dr. William R.
Graham, acting director of the space agency, said on Sunday.
He said that the plume seems to start \"near a live seam\", but it is not yet certain whether the plume occurs at or just near the seam.
On Thursday, at the first meeting of the presidential commission investigating the cause of the accident, the safety of the seal also became an important issue.
The space agency acknowledged that it had negotiated with rocket maker Morton tiokor.
Worried that the cold weather at the launch site could weaken the seals.
But an acting official told the commission that the manufacturer had agreed to launch.
Lovingood, deputy manager of the Marshall Space Shuttle program, also admitted that after the previous shuttle flight, concerns were raised about erosion damage to some seals, but said that a thorough investigation had been conducted on the issue.
It needs to be sealed, because the booster is not a single long structure, but four large cylindrical sections bolted together with other components, and the rocket is ready to launch at the Kennedy Space Center.
Although the side of the rocket may be leak-proof to the naked eye, there is room for gas leakage at the seams.
As a result, rocket engineers designed a series of sealing devices and other barriers to blocking gas.
The two most important seals are O-rings, basically big doughnuts.
Forming parts of synthetic rubber, a tiny gap between the two cylindrical sections where the filling bolts are connected together.
The O-ring itself can prevent heat and flame damage through the initial barrier of putty.
If the flame and heat are to escape through the joint between the rocket section, they usually have to pass through the putty first, then through the main O-ring, and finally through the back-up ring.
The rubber O-ring is designed to be particularly tightly sealed when subjected to high impact
The pressure gas, like the rubber gasket on the faucet, is tightly sealed to prevent water leakage.
At a meeting of the presidential council on Thursday
Lovingood at Marshall Space Center was asked if experts had looked at the joints in reconstruction
After the previous shuttle flight, the booster can be used to see if there is evidence of a leak.
\"We have seen some evidence of erosion of these seals, the main seals,\" he said . \".
\"We have never seen any erosion of the secondary seal.
But we have seen evidence of soot between the two SEALs.
Asked if it was a concern, he replied, \"Oh, yes.
I mean, this is an abnormal phenomenon, and it has been completely resolved, and all the investigation work we have done in this area is fully documented.
There is no clear reference in the internal documentation to the possibility that cold weather may weaken the seal by contracting or hardening or other effects.
Instead, the memos focus on the erosion and thermal effects observed on seals after previous flights.
However, a memorandum does indicate that \"environmental effects such as moisture\" may be an indirect factor contributing to erosion.
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Last summer, a memo prepared by the Office of the auditor general at NASA Headquarters used terrible terminology to describe potential problems with burning and erosion that could compromise seal effectiveness.
The memorandum of July 23, 1985 was given to Michael B.
Richard C. Mann, head of the Space Shuttle Project Resource Analysis Department
Ring was \"destroyed\" by the advertisement.
Cook warned that the \"seal burning\" recently observed on the shuttle could cause \"significant problems affecting flight safety and project costs \".
At the junction of the rocket nozzle section and the adjacent section, \"Not only was the first O-ring destroyed, but the second O-ring was also partially eaten,\" the memo said . \".
The memo does not state the frequency of this happening.
The coalition mentioned in the memo is a recent place where the flame plume appears from the side of the rocket before the explosion destroys the challenger.
The memo says the cause of the erosion problem has not been determined.
\"However, there is almost no problem, flight safety has been and is still affected by the potential failure of the seals,\" it said, and it is acknowledged that the failure in the launch process is certainly disastrous.
The memo says the leadership of the space flight program is \"looking at the situation with the most serious attitude \".
\"Another memo prepared by Owen Daviz, an engineer at NASA\'s headquarters shuttle rocket booster program, at about the same time describes his visit to the Marshall Space Flight Center on July 11, 1985, discuss the \"seal erosion problem\" affecting O-rings on several shuttles \".
More than a dozen examples this memo says, \"There are 12 examples in flight,\" where the nozzle part of the rocket is tied to the adjacent part at the seams and the main O-ring is eroded a bit.
In both cases, the main seal actually blows out soot, and in one case, the backup seal also shows erosion, the memo said.
This observation and Mr.
Cook\'s memo seems to contradict his views.
Lovingood claimed no erosion of the secondary seal was observed.
The document added that the main suspect causing erosion was the type of putty used.
It says that Molton tiokor, the manufacturer of the booster rocket, believes that putty made by another unidentified manufacturer can form holes under certain conditions that produce a \"spray effect\", apparently, this shows that these holes can concentrate the hot gas on the seal.
\"There seems to be no verified resolution for the effect of putty,\" Mr. Davids wrote.
The memorandum also describes the erosion of O-rings at the junction of other major components of the rocket.
It says that during the flight, there were five erosion of the main ring, and the rear ring appeared at one time.
Although it was not eroded, the up ring was affected by heat.
It added that the first key issue was that, with the increase in the internal pressure of the rocket, the resulting rotational force resulted in the \"falling off\" or \"off-seat\" of the secondary ring \", A problem that has been known for quite a long time.
One suggestion to eliminate this issue, the memo says, is a \"capture feature\" that does not have other descriptions, which will prevent the seal from falling off.
Memorandum from Sir.
Letter from Mr. Davide
Moore, assistant space flight administrator.
For the rest of the year, O-rings remain a concern for some engineers and budget analysts. On Aug.
21, 1985, budget briefing for top
NASA\'s top officials list the burning of the Rings as one of the biggest \"budget threats\" to the entity.
The fuel booster program, obviously, means that it can become expensive to solve this problem.
Other recent reports.
1985, a status report and briefing prepared by NASA\'s propulsion department said that the recently completed shuttle mission showed that, the primary ring at the joint between the nozzle and the adjacent section has a \"slight erosion\" damage at other joints.
It also lists the burning of the ring at the top of the \"solid rocket booster problem\" list.
\"In December 1985, a monthly status report again listed chartered cars as one of the seven questions about boosters.
Concerns about the seal were expressed at least as early as 1982 of the institutional documents.
\"List of key items\" for solids \"-
Fuel Booster rocket dated December.
1982, the joints are described in the most important categories.
The document also says that \"combined rotation\" may knock down the back as rocket pressure rises --up ring.
This is the same problem, according to Mr.
Davids\'s memo was still unresolved in July 1985, although it has been \"known\" for a long time.
\"A version of this article appears on page 1001001 of the national edition of February 9, 1986, titled: NASA warns that boosters pose a disaster risk.