GioFX
04-05-2004, 10:55
Posterò entro giugno la storia e le caratteristiche dello Space Shuttle, intanto qui andranno le notizie riguardo il Return To Flight del programma STS.
NASA Releases Shuttle Return to Flight Plan
By Leonard David
Senior Space Writer
posted: 10:00 pm ET
30 April 2004
NASA released today a status report on safely returning space shuttles to flight. Presently, the space agency has a shuttle liftoff slated for no earlier than March 2005.
Called NASA's Implementation Plan for Space Shuttle Return to Flight and Beyond – Revision 2, the report is putting into action the Columbia Accident Investigation Board (CAIB) recommendations after the tragic loss of the seven-person crew and craft on February 1, 2003 during atmospheric reentry.
NASA’s just issued plan points out that "considerable progress" has been made in the past months in the agency’s return to flight efforts and to make the Shuttle safer.
"We’re feeling very good about being back in the flying mode next spring," Wayne Hale, Space Shuttle Program Deputy Manager said in a press briefing today in discussing the return to flight status of the space plane.
Since the first status report was issued some five months ago, the plan has been "continually updated to record NASA’s progress toward safe return to flight as well as activities to institutionalize the technical, managerial, cultural, communications, and safety changes necessary to sustain safe flight operations for as long as the space shuttle’s unique capabilities are needed," the report says.
"We think we have our arms around all the problems that we need to address…all the changes that are required to be made and all the work that we have to do to get ready to fly," Hale said.
Retiring the shuttle
The physical cause of the Columbia accident centered on insulation foam shed from the space shuttle’s huge external tank, specifically from the left bipod ramp on the fuel tank. That debris struck the underside of the leading edge of Columbia’s left wing. This impact created a breach in the wing that permitted superheated air to enter and destroy the wing structure during reentry into the Earth’s atmosphere.
When NASA returns to flight, the space shuttle "will be the safest it has ever been," the report explains. The agency report underscores confidence in maintaining that level of safety throughout the life of the shuttle program.
NASA is under White House direction by President George W. Bush to return the shuttle to flight as soon as possible, but retire from service the space plane by 2010, the same year when the International Space Station (ISS) is to be fully-finished.
Ascent debris
The implementation report stresses that extensive work is ongoing to eliminate critical ascent debris -- the root cause that led to the Columbia accident.
NASA is redesigning the external tank bipod assembly to eliminate the large foam ramp and replace it with electric heaters to prevent ice formation. Furthermore, other potential sources of critical ascent debris are being identified and eliminated, the report says.
NASA is already pursuing a comprehensive testing program to understand the root causes of foam shedding and develop alternative design solutions to reduce the debris loss potential. Lastly, the space agency is slated to conduct tests and analyses to ensure that the shuttle can withstand potential strikes from "noncritical" ascent debris.
"We’re keeping the computers humming to understand all that," Hale explained.
The real constraint to return to flight is clearly, number one, fixing the external tank, Hale told SPACE.com. "That has been pacing the item for return to flight from the very beginning."
Hale said that much has been learned about the external tank foam, how it adheres to complex geometric shapes, and its reaction during aerodynamic heating and acceleration loads.
"Right now, our launch date is based on fixing the tank and having some management reserve in that schedule for any surprises that we may encounter as we go down that fix path to make a launch in the spring," Hale added.
Mile-markers in the rearview mirror
For the time being, the report explains, NASA will launch space shuttle missions in daylight conditions to maximize imagery capability "until we fully understand and can mitigate the risk" that debris poses to the shuttle during liftoff.
Hale told reporters that shuttle return to flight teams have more than a light at the end of the tunnel…"but we have work to do." He reiterated a recent comment from an associate: "We’re starting to see mile-markers in the rearview mirror. We’re making progress and we’re on the road."
There are other issues that are demanding time, called "unknown unknowns", said John Casper, former astronaut and Deputy of the Return to Flight Planning Team and Manager of the Space Shuttle Program Management Integration and Planning Office.
Casper told SPACE.com that one shuttle fix that bears watching: flex hoses. "We’ve gotten cracks in some of these flex hoses. There are over 200 on each vehicle. We’re now working a plan to repair, replace those flex hoses to make the March date. It is taking a lot of time and attention," he said.
On-orbit scrutiny
The implementation plan notes that efforts are underway to expand the use of "appropriate national assets" -- such as orbiting spysats and top-secret ground gear -- to evaluate the condition of a space shuttle orbiter while circling around the Earth.
NASA has already concluded a Memorandum of Agreement with the National Imagery and Mapping Agency -- subsequently renamed the National Geospatial-Intelligence Agency (NGA)) that provides for on-orbit assessment of the condition of each orbiter vehicle as a standard requirement.
In this regard, NASA has identified what administrative positions and people should have access to such sensitive data churned out by classified hardware. Plans to demonstrate and train people in these new processes have been developed and will be exercised over the next few months, well before the launch of STS-114, now headed for liftoff no earlier than March of next year.
"Since this action may involve receipt and handling of classified information, the appropriate security safeguards will be observed during its implementation," the report notes.
Repairs in space
NASA has developed a "flip around" operation to allow thermal protection system (TPS) repairs while the shuttle is docked to the International Space Station. This idea involves turning the Shuttle into a belly-up position that provides robotic arm access to a damaged TPS repair site, and supports space walking fix-it astronauts.
To deal with damage to tiles and wing leading edge segments, NASA, the United States Air Force Research Laboratory, and industry teams have come up with three complementary repair concepts. Together, the report explains, the concepts enable repair of a wide variety of potential damage to the shuttle’s reinforced carbon carbon (RCC) panels used to thwart the intense heat of reentry.
Plug Repair consists of an insert intended to repair small holes in the wing’s leading edge. A Rigid Wrap concept is a complete overwrap for a given RCC panel intended to repair any catastrophic damage detected on a given panel. Lastly, a Crack Repair concept uses a material application intended to fill cracks and small holes in a wing’s leading edge.
At present, the tile repair materials and tools should be ready in the December 2004–March 2005 timeframe, the report explains.
Public safety
The NASA report also details work in progress to evaluate the risk of public overflight of a reentering shuttle en route to a landing. Chunks of Columbia were strewn across a large swath of U.S. territory as the space plane was heading for landing at the Kennedy Space Center in Florida.
"Controls such as entry ground track and landing site changes will be considered to balance and manage the risk to persons, property, flight crew, and vehicle," the report says.
NASA is studying the relative public risks associated with entry to its three primary landing sites: Kennedy Space Center in Florida; Edwards Air Force Base in California; and White Sands Space Harbor/Northrup in New Mexico.
"The results of these analyses will determine if some ground tracks must be removed from consideration as normal, preplanned, end-of-mission landing opportunities," the report states.
Rescue at the ready
NASA is also moving forward on developing a shuttle-to-shuttle rescue capability, now called STS-300.
This activity is dedicated to having the means to accelerate the processing of the next vehicle scheduled for launch to make it available in the event a rescue mission is required.
This work will be completed before STS-114, the newly-issued implementation plan says, and will make the rescue mission available for return to flight and all subsequent flights.
Eileen Collins -- the first (and currently only) female Shuttle commander -- will command the STS-114 "Return to Flight" mission, the first after the Columbia tragedy. Shuttle Discovery is the space plane of choice for the mission.
Discovery is now targeted to launch no earlier than the period between March 6 and April 18, 2005. The mission would last 12 days, with the shuttle crew of seven arriving at the International Space Station.
NASA Releases Shuttle Return to Flight Plan
By Leonard David
Senior Space Writer
posted: 10:00 pm ET
30 April 2004
NASA released today a status report on safely returning space shuttles to flight. Presently, the space agency has a shuttle liftoff slated for no earlier than March 2005.
Called NASA's Implementation Plan for Space Shuttle Return to Flight and Beyond – Revision 2, the report is putting into action the Columbia Accident Investigation Board (CAIB) recommendations after the tragic loss of the seven-person crew and craft on February 1, 2003 during atmospheric reentry.
NASA’s just issued plan points out that "considerable progress" has been made in the past months in the agency’s return to flight efforts and to make the Shuttle safer.
"We’re feeling very good about being back in the flying mode next spring," Wayne Hale, Space Shuttle Program Deputy Manager said in a press briefing today in discussing the return to flight status of the space plane.
Since the first status report was issued some five months ago, the plan has been "continually updated to record NASA’s progress toward safe return to flight as well as activities to institutionalize the technical, managerial, cultural, communications, and safety changes necessary to sustain safe flight operations for as long as the space shuttle’s unique capabilities are needed," the report says.
"We think we have our arms around all the problems that we need to address…all the changes that are required to be made and all the work that we have to do to get ready to fly," Hale said.
Retiring the shuttle
The physical cause of the Columbia accident centered on insulation foam shed from the space shuttle’s huge external tank, specifically from the left bipod ramp on the fuel tank. That debris struck the underside of the leading edge of Columbia’s left wing. This impact created a breach in the wing that permitted superheated air to enter and destroy the wing structure during reentry into the Earth’s atmosphere.
When NASA returns to flight, the space shuttle "will be the safest it has ever been," the report explains. The agency report underscores confidence in maintaining that level of safety throughout the life of the shuttle program.
NASA is under White House direction by President George W. Bush to return the shuttle to flight as soon as possible, but retire from service the space plane by 2010, the same year when the International Space Station (ISS) is to be fully-finished.
Ascent debris
The implementation report stresses that extensive work is ongoing to eliminate critical ascent debris -- the root cause that led to the Columbia accident.
NASA is redesigning the external tank bipod assembly to eliminate the large foam ramp and replace it with electric heaters to prevent ice formation. Furthermore, other potential sources of critical ascent debris are being identified and eliminated, the report says.
NASA is already pursuing a comprehensive testing program to understand the root causes of foam shedding and develop alternative design solutions to reduce the debris loss potential. Lastly, the space agency is slated to conduct tests and analyses to ensure that the shuttle can withstand potential strikes from "noncritical" ascent debris.
"We’re keeping the computers humming to understand all that," Hale explained.
The real constraint to return to flight is clearly, number one, fixing the external tank, Hale told SPACE.com. "That has been pacing the item for return to flight from the very beginning."
Hale said that much has been learned about the external tank foam, how it adheres to complex geometric shapes, and its reaction during aerodynamic heating and acceleration loads.
"Right now, our launch date is based on fixing the tank and having some management reserve in that schedule for any surprises that we may encounter as we go down that fix path to make a launch in the spring," Hale added.
Mile-markers in the rearview mirror
For the time being, the report explains, NASA will launch space shuttle missions in daylight conditions to maximize imagery capability "until we fully understand and can mitigate the risk" that debris poses to the shuttle during liftoff.
Hale told reporters that shuttle return to flight teams have more than a light at the end of the tunnel…"but we have work to do." He reiterated a recent comment from an associate: "We’re starting to see mile-markers in the rearview mirror. We’re making progress and we’re on the road."
There are other issues that are demanding time, called "unknown unknowns", said John Casper, former astronaut and Deputy of the Return to Flight Planning Team and Manager of the Space Shuttle Program Management Integration and Planning Office.
Casper told SPACE.com that one shuttle fix that bears watching: flex hoses. "We’ve gotten cracks in some of these flex hoses. There are over 200 on each vehicle. We’re now working a plan to repair, replace those flex hoses to make the March date. It is taking a lot of time and attention," he said.
On-orbit scrutiny
The implementation plan notes that efforts are underway to expand the use of "appropriate national assets" -- such as orbiting spysats and top-secret ground gear -- to evaluate the condition of a space shuttle orbiter while circling around the Earth.
NASA has already concluded a Memorandum of Agreement with the National Imagery and Mapping Agency -- subsequently renamed the National Geospatial-Intelligence Agency (NGA)) that provides for on-orbit assessment of the condition of each orbiter vehicle as a standard requirement.
In this regard, NASA has identified what administrative positions and people should have access to such sensitive data churned out by classified hardware. Plans to demonstrate and train people in these new processes have been developed and will be exercised over the next few months, well before the launch of STS-114, now headed for liftoff no earlier than March of next year.
"Since this action may involve receipt and handling of classified information, the appropriate security safeguards will be observed during its implementation," the report notes.
Repairs in space
NASA has developed a "flip around" operation to allow thermal protection system (TPS) repairs while the shuttle is docked to the International Space Station. This idea involves turning the Shuttle into a belly-up position that provides robotic arm access to a damaged TPS repair site, and supports space walking fix-it astronauts.
To deal with damage to tiles and wing leading edge segments, NASA, the United States Air Force Research Laboratory, and industry teams have come up with three complementary repair concepts. Together, the report explains, the concepts enable repair of a wide variety of potential damage to the shuttle’s reinforced carbon carbon (RCC) panels used to thwart the intense heat of reentry.
Plug Repair consists of an insert intended to repair small holes in the wing’s leading edge. A Rigid Wrap concept is a complete overwrap for a given RCC panel intended to repair any catastrophic damage detected on a given panel. Lastly, a Crack Repair concept uses a material application intended to fill cracks and small holes in a wing’s leading edge.
At present, the tile repair materials and tools should be ready in the December 2004–March 2005 timeframe, the report explains.
Public safety
The NASA report also details work in progress to evaluate the risk of public overflight of a reentering shuttle en route to a landing. Chunks of Columbia were strewn across a large swath of U.S. territory as the space plane was heading for landing at the Kennedy Space Center in Florida.
"Controls such as entry ground track and landing site changes will be considered to balance and manage the risk to persons, property, flight crew, and vehicle," the report says.
NASA is studying the relative public risks associated with entry to its three primary landing sites: Kennedy Space Center in Florida; Edwards Air Force Base in California; and White Sands Space Harbor/Northrup in New Mexico.
"The results of these analyses will determine if some ground tracks must be removed from consideration as normal, preplanned, end-of-mission landing opportunities," the report states.
Rescue at the ready
NASA is also moving forward on developing a shuttle-to-shuttle rescue capability, now called STS-300.
This activity is dedicated to having the means to accelerate the processing of the next vehicle scheduled for launch to make it available in the event a rescue mission is required.
This work will be completed before STS-114, the newly-issued implementation plan says, and will make the rescue mission available for return to flight and all subsequent flights.
Eileen Collins -- the first (and currently only) female Shuttle commander -- will command the STS-114 "Return to Flight" mission, the first after the Columbia tragedy. Shuttle Discovery is the space plane of choice for the mission.
Discovery is now targeted to launch no earlier than the period between March 6 and April 18, 2005. The mission would last 12 days, with the shuttle crew of seven arriving at the International Space Station.