Autor Wątek: Katastrofa Challengera (STS-51-L)  (Przeczytany 10477 razy)

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Offline Orionid

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Odp: Katastrofa Challengera (STS-51-L)
« Odpowiedź #45 dnia: Luty 01, 2018, 02:47 »
Lost Innocence: Remembering the Sacrifice of the Challenger Seven (Part 1)
By Ben Evans January 29th, 2018

Next, turbine temperatures increased due to the leaner fuel mixture feeding into the combustion chambers from the External Tank. Otherwise, the Rogers report continued, “engine operation was normal.” They did not contribute to the loss of 51L. Nor did the gigantic tank itself, of which 20 percent was recovered, mostly debris from the inter-tank and the lowermost hydrogen section. Initial speculation that there had been premature detonation of range safety explosives was discounted, partly because the unexploded ordnance was among the debris, as were theories of structural imperfections in the tank’s design or damage incurred at liftoff. The possibility of a liquid hydrogen leak at liftoff was also dismissed, since it would immediately have been ignited by the exhaust from the Solid Rocket Boosters or main engines and would have been evident in the downlinked telemetry data.

In total, around 30 percent of Challenger was found, and inspections revealed that she had disintegrated as a result of massive aerodynamic overloads, with no evidence of internal burn damage or exposure to explosive forces. Chemical analyses indicated that her right side had been sprayed with hot gases from the leaking SRB, but telemetry indicated that all of her systems operated normally until shortly prior to the breakup. No problems were detected with either of her payloads. The Spartan-203 free-flying solar satellite was unpowered during ascent and the deployment ordnance for the Inertial Upper Stage (IUS) and the Tracking and Data Relay Satellite (TDRS-B) showed no indication of having prematurely activated.

http://www.americaspace.com/2018/01/29/missed-warnings-the-fatal-flaws-which-doomed-challenger-32-years-ago-part-1/

Missed Warnings: The Fatal Flaws Which Doomed Challenger 32 Years Ago (Part 2)
By Ben Evans January 30th, 2018

A little over three weeks later, on 30 October 1985, Challenger flew Mission 61A, experiencing nozzle O-ring erosion and blow-by at the SRB field joints; neither of these problems were identified at the Flight Readiness Review for the next mission, 61B, in November. Indeed, that flight also suffered nozzle O-ring erosion and blow-by. By early December, in response to these problems, Thiokol recommended that their testing equipment needed to be redesigned.

Only days later, on the 10th, the company requested closure of the O-ring critical problem issue, citing satisfactory test results, future plans, and work carried out thus far by its task force. This closure request was harshly criticized by the Rogers investigators. One panel member pointed out to the Thiokol senior managers: “You close out items that you’ve been reviewing flight by flight—that have obviously critical implications—on the basis that, after you close it out, you’re going to continue to try to fix it. What you’re really saying is [that] you’re closing it out because you don’t want to be bothered.”

http://www.americaspace.com/2018/01/30/missed-warnings-the-fatal-flaws-which-doomed-challenger-32-years-ago-part-2/

Offline ekoplaneta

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Odp: Katastrofa Challengera (STS-51-L)
« Odpowiedź #46 dnia: Styczeń 24, 2019, 12:56 »
Ciekawy artykuł o skutkach wynikłych z katastrofy Challengera dla amerykańskiej astronautyki:

https://library.cqpress.com/cqresearcher/document.php?id=cqresrre1986020700

Artykuł pisany jest z perspektywy 1986 roku  :) Gdyby nie katastrofa promu w maju 1986 miały polecieć promem sondy: Ulisses i Galileo w odstępie 6 dni. Zaś jesienią miał polecieć HST (oczywiście z niewykrytą wówczas wadą lustra). Galileo dotarłby do Jowisza w 1988 roku i sześć lat później mógłby obserwować impakt komety Shoemaker Levy w 1994 z perspektywy orbity Jowisza! Wtedy byłaby zabawa! Niestety awaria Challengera skazała na obserwację impaktu z trajektorii międzyplanetarnej i z orbity przez naprawiony już HST. Dziwne, że w artykule nic nie wspominają o misji Mars Observer, która też miała startować na promie kosmicznym.

Offline ekoplaneta

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Odp: Katastrofa Challengera (STS-51-L)
« Odpowiedź #47 dnia: Styczeń 28, 2019, 14:03 »
Dziś mija 33 lata od katastrofy Challengera!  :(

Offline Orionid

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Odp: Katastrofa Challengera (STS-51-L)
« Odpowiedź #48 dnia: Styczeń 28, 2019, 18:20 »
'Major Malfunction': Remembering the Sacrifice of the Challenger Seven
By Ben Evans, on January 28th, 2019

(...) A little under eight seconds into the mission, as planned, the vehicle cleared the tower and began a programmed roll maneuver, moving onto the correct flight azimuth for a 28.45-degree orbit, then pitching onto her back under the control of her computers. Shortly thereafter, at T+19 seconds, to prepare herself for passage through a period of maximum aerodynamic turbulence (known as “Max Q”), Challenger’s main engines were throttled down from 104 to 94 percent, and later 65 percent, of rated thrust. Thirty-seven seconds into the ascent, she encountered the first of several high altitude wind shears, lasting until just past a minute after launch. In its inquiry, the Rogers Commission report noted that the shuttle’s guidance, navigation, and control system immediately detected and compensated for these conditions, and—although 51L’s aerodynamic loads were higher than previous missions in both the yaw and pitch planes—the SRBs, too, responded effectively to all commands.


Freezing conditions, as evidenced by large concentrations of ice on Pad 39B, were co-conspirators in Challenger’s destruction on 28 January 1986. Photo Credit: NASA

It is possible that the mission may still have proceeded normally, had the plug of solid fuel remained jammed into the O-ring breach. However, by an incredible stroke of cruel luck, Challenger happened to pass through the most severe wind shear ever encountered by an ascending shuttle stack. The shear dislodged the plug around a minute into the mission. After passing through maximum aerodynamic turbulence, 51 seconds into the climb, her main engines were throttled back up to full power; shortly afterward, at 58.788 seconds, a frame of video recorded the first evidence of a flickering flame from the right-hand SRB’s aft joint. The temporary plug of solid fuel had gone, and, although they were oblivious to anything amiss, the crew’s fate was now sealed.

The flame rapidly established itself, growing into a well-defined plume within half a second. Exactly a minute into the mission, downlinked telemetry pointed to an unusual chamber pressure differential between the left and right boosters—the pressure of the latter was some 11.8 psi (81.3 kPal) lower than the other, indicating a leak in its aft joint. As the flame increased in size, Challenger’s aerodynamic “slipstream” deflected it backward and circumferentially by the protruding structure of the upper ring which linked the SRB to the External Tank, focusing the flame directly onto the surface of the tank. Sixty-two seconds into the ascent, the left booster’s thrust vector control moved to compensate for the yaw motion caused by the reduced thrust from its right-side counterpart. A couple of seconds later came the first visual manifestation that the flame from the damaged booster had breached the lower segment of the External Tank: an abrupt change in the shape and color of the flame, indicating that it was now mixing with leaking liquid hydrogen. Moreover, pressurization data at around this point reinforced the fact that its liquid hydrogen tank was indeed ruptured. (...)

https://www.americaspace.com/2019/01/28/major-malfunction-remembering-the-sacrifice-of-the-challenger-seven/

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Odp: Katastrofa Challengera (STS-51-L)
« Odpowiedź #49 dnia: Styczeń 28, 2019, 22:33 »
Son of space shuttle Challenger commander remembers tragedy 33 years ago
Posted: 4:50 AM, Jan 28, 2019  Updated: 1:48 PM, Jan 28, 2019



For Lt. Gen. Richard "Rich" Scobee, losing his father in the explosion of the space shuttle Challenger was a personal tragedy he and the families of other members of the crew have shared with the nation for 33 years.

"If you have ever lost somebody that you loved, it's that exact feeling," Scobee told CNN this month, as the anniversary approached. "I just shared my loss with the country. I think it's my responsibility to share some of that -- because it's part of our history."

On January 28, 1986, Scobee was about to graduate from the Air Force Academy when he joined his mother and the other crew members' families in Florida to watch his father, mission commander Dick Scobee and six other astronauts blast off aboard Challenger.

He remembers standing on the roof of NASA's Mission Control at the Kennedy Space Center and being excited that the crystal clear sky would offer a perfect view of the separation of Challenger's solid rocket boosters.

Seconds after liftoff, "I knew something was wrong immediately," Scobee recalls. "I looked at my mom and she had figured that out too."

Watching his mother, June, go through it was horrible memory that has never left him.

"After all these years it's still tough to recall -- the sadness in her eyes."

Her career as an English professor helped her bond closely with the civilian member of Challenger's crew, Christa McAuliffe.

The world remembers McAuliffe as NASA's first "teacher in space." Students in countless classrooms watched in horror that day as the disaster unfolded on live TV.

After an investigation, the explosion was blamed on a seal inside a rocket booster which leaked due to cold weather. Hot exhaust escaped through the seal and ruptured the shuttle's external fuel tank, triggering an explosion.

Commander Scobee lost his life along with McAuliffe and five other crewmates: Gregory Jarvis, Ronald McNair, Ellison Onizuka, Judith Resnik and Mike Smith.

The horrifying public aspect of the tragedy sometimes overshadows the rest of Dick Scobee's life. "Everyone saw how my father died and they saw the end of his career," his son said. "What they didn't see was his life -- which was amazing."

From mechanic to astronaut

Dick Scobee started his Air Force career as an engine mechanic and worked his way through school and the military to become an officer, combat pilot and test pilot before winning a spot in NASA's astronaut corps.

"Going from turning wrenches on a flight line to commanding a space shuttle -- no country in the world could you do that except for this one," Rich Scobee said.

Dick Scobee's leadership qualities were legendary among his colleagues. "That guy would make you feel good about you," his son recalled. "He just had a way of making you feel successful."

In the years after Challenger, Rich Scobee embarked on his own military career as an F-16 fighter pilot. Eventually he would see combat in the Persian Gulf War, become a squadron commander and, later, commander of Kirkuk Air Base in Iraq.

Scobee said his father taught him important life lessons that have been useful throughout his career. Along the way, Rich Scobee and his wife Janis found time to raise a family of their own, including two sons and a daughter.

Last fall, Rich Scobee was promoted to Air Force three-star general and assumed command of the Air Force Reserve.

"The Reserve exists to capture the talent of trained airmen who are leaving the active Air Force, but who still want to serve part-time," Scobee said. It allows the Pentagon the ability to quickly increase air power if needed, by using Reserve units.

"We're always ready," said Scobee. "72 hours is all the notice we need" to launch fighter jets, bombers, tankers, cargo transports to any destination. It's all done for about one sixth of what it would cost for the full-time Air Force, said Scobee. Plus, the Air Force Reserve offers 20% of the total Air Force capability for only 2% of the total Air Force budget.

The future of American space exploration

Appropriately, Scobee's command will indirectly intersect with NASA later this year. Air Force Reserve units are scheduled to provide support for the first astronaut launches from Florida since the demise of the shuttle program in 2011.

The astronauts are scheduled to blast off from Florida later this year to test two different capsules for human spaceflight -- Boeing's Starliner and SpaceX's Dragon.

Assigned to those missions will be Air Force Reserve "Guardian Angel" pararescue teams with the 920th Rescue Wing -- to respond to possible emergencies during launches or landings.

Scobee, who grew up talking about this subject with his father often, believes space exploration is important and the United States should assume a leadership role.

"We have to take a rightful place as leaders in space. We can't let that go," Scobee said.

He supports the idea of sending astronauts to Mars. "Although space is dangerous -- as explorers we need to go because we don't fully understand things until one of us touches it," he said.

"Manned space flight is really important to who we are."

https://www.thedenverchannel.com/news/national/son-of-space-shuttle-challenger-commander-remembers-tragedy-33-years-ago