[Space] NASA - STS-115 - ISS 12A (Atlantis)

[GioFX]

Originariamente inviato da Octane

Un'altra foto dell'arrivo dell'Atlantis alla piattaforma di lancio:

stupendo, nella nebbia è ancora più incredbile...

[adsasdhaasddeasdd]

malo sciatol russo non vola più??

[Legolas84]

Shuttle

[albertoz85]

Originariamente inviato da PhantomReloaded

malo sciatol russo non vola più??

Se ti riferisci al Buran, ha volato una volta, 20 anni fa, senza equipaggio, e l'unico esemplare costruito è andato distrutto...
Tu ci facevi ancora conto?

[GioFX]

Originariamente inviato da albertoz85

Se ti riferisci al Buran, ha volato una volta, 20 anni fa, senza equipaggio, e l'unico esemplare costruito è andato distrutto...
Tu ci facevi ancora conto?

correggo: Buran è il nome dell'orbiter 1.01, l'unico pronto e certificato per il volo. Ptichka è invece il secondo orbiter costruito, identificato con la sigla 1.02, la cui costruzione è inziata nel 1988 e poi sospesa con la chiusura del programma nel 1993, quando era pronto al 97%. Oggi è di proprietà del Kazakistan, si trova ora all'ingresso del complesso turistico all'interno del cosmodromo di Baikonur.



Atri 2 orbiter, 2.01, 2.02 sono rimasti incompleti, mentre il 2.03 è stato smantellato.

Altre informazioni su:

www.buran.ru

www.k26.com/buran

Ma vi prego, questo 3d è solo per la missione in oggetto del programma STS, le discussioni sul Buran vanno in un apposito 3d, o in quello globale...

[albertoz85]

Originariamente inviato da GioFX

correggo: Buran è il nome dell'orbiter 1.01, l'unico pronto e certificato per il volo. Ptichka è invece il secondo orbiter costruito, identificato con la sigla 1.02, la cui costruzione è inziata nel 1998 e poi sospesa con la chiusura del programma nel 1993, quando era pronto al 97%. Oggi è di proprietà del Kazakistan, si trova ora all'ingresso del complesso turistico all'interno del cosmodromo di Baikonur.

Si si, difatti ho scritto l'unico esemplare costruito, intendendo "pronto al volo"
Ti faccio io una correzione, ti è scappato un 1998 invece di 1988

[GioFX]

Originariamente inviato da albertoz85

Si si, difatti ho scritto l'unico esemplare costruito, intendendo "pronto al volo"
Ti faccio io una correzione, ti è scappato un 1998 invece di 1988

grazie ci siamo corretti a vicenda

la mia cmq non era una correzione, quanto più una puntalizzazione, dato che è talmente comune il riferimento al Buran che il programma stesso è stato definito Buran Space Program in occidente.

[lele980]

ragazzi scusate l OT ma credo che voi sicuramente mi possiate meglio indirizzare visto l attinenza del discorso:

vorrei che mi indirizzaste su qualche link o discussione riguardanti la serie hyper-x della nasa e tutti i futuri progetti della sostituzione dello shuttle dato che ufficialmente nel 2010 lo shuttle andra' in pensione, ma ancora devo capire cosa lo sostituira' . e se nn ci fosse ancora l alternativa, cosa succedera'?

[guyver]

che la nasa resterà a terra

[albertoz85]

Originariamente inviato da lele980

ragazzi scusate l OT ma credo che voi sicuramente mi possiate meglio indirizzare visto l attinenza del discorso:

vorrei che mi indirizzaste su qualche link o discussione riguardanti la serie hyper-x della nasa e tutti i futuri progetti della sostituzione dello shuttle dato che ufficialmente nel 2010 lo shuttle andra' in pensione, ma ancora devo capire cosa lo sostituira' . e se nn ci fosse ancora l alternativa, cosa succedera'?

Il programma è già definito da qualche anno, si tratta del Project Constellation, puoi trovare tutto sul sito nasa (ovviamente )

http://www.nasa.gov/mission_pages/ex...craft/cev.html
http://www.nasa.gov/mission_pages/ex...ain/index.html

[GioFX]

C'è l'indice in alto!

http://www.hwupgrade.it/forum/showthread.php?p=9551606

[GioFX]

Da Spaceflightnow.com:

Shuttle communications antenna bolts a concern

BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: August 13, 2006

Engineers are trying to determine whether critical bolts holding the shuttle Atlantis' KU-band antenna box in place are securely threaded, a potentially serious issue that could require tricky repairs before the ship's Aug. 27 launch, sources said Sunday.


File image of KU-band antenna stowed in Atlantis payload bay. Credit: NASA-KSC

A two-day flight readiness review to assess Atlantis' ground processing, to resolve open issues and to set an official launch date begins Tuesday at the Kennedy Space Center. The launch window for the 116th shuttle mission opens Aug. 27 at 4:30 p.m. and closes Sept. 7.

The KU-band antenna bolt issue will be discussed Monday, but it's not yet clear whether the issue can be resolved before the flight readiness review begins or whether additional work will be needed to determine what, if anything, needs to be done.

The issue involves four bolts that hold the antenna support box to the forward right side of Atlantis' cargo bay. The KU-band antenna is used to relay voice, video and data between the shuttle and NASA's fleet of communications satellites.

During an earlier launch campaign, engineers discovered problems with a certain type of bolt that in some cases were too short and not sufficiently threaded, or screwed in. Engineers began an assessment of similar bolts used elsewhere in the shuttle.

As it turns out, the same type bolts are used to secure the shuttle's KU-band antenna box to the payload bay wall. Engineers replaced the bolts in the shuttles Discovery and Endeavour but not in Atlantis


File image of KU-band antenna deployed in space

The bolts have been in place since the antenna was installed aboard Atlantis and there has never been a problem. But it is known that some of the bolts could be engaged just a few threads worth because of a "tolerance stackup" in the way the bolts and washers are installed, according to engineers familiar with the matter.

Should the box break free during ascent, it would fall the length of the shuttle's 60-foot-long cargo bay and could cause catastrophic damage.

The bolts in question cannot be easily inspected at the launch pad. Kennedy Space Center engineers are studying paperwork and earlier analyses to determine whether the bolts are, in fact, sufficiently threaded. At the same time, sources said, they also are studying ways to replace the bolts at the pad, if necessary, a procedure that has never been done before.

Atlantis' launch window is defined by the international space station's orbit and by a post-Columbia requirement to launch two missions in daylight for photo documentation of the shuttle's heat shield and external tank foam insulation.

Because of unexpected foam shedding during the first post-Columbia mission last year, NASA extended the daylight requirement to the third flight in the sequence.

The shuttle Discovery successfully flew in July and a repeat performance by Atlantis would clear the way for the resumption of night launchings, greatly expanding available launch windows.

But if Atlantis isn't off the ground by the end of the September window, NASA would be faced with the prospect of just two launch days in October, none in November and just one in December. As such, agency engineers want to resolve the bolt issue as soon as possible.

[GioFX]

Aggiornamento di Dave (United Space Alliance):

the KU band ant. bolt problem is a PBA (Probably Be Alright). This has been know for well over 1 1/2 weeks. If required they can be changed on the pad,

[lele980]

Originariamente inviato da GioFX

C'è l'indice in alto!

http://www.hwupgrade.it/forum/showthread.php?p=9551606

sono cecato, grazie e scusate

[GioFX]

Da NasaSpaceFlight.com:

NASA give approval for Atlantis launch

Chris Bergin, 8/16/2006 3:48:00 PM

Managers at NASA's Flight Readiness Review (FRR) in Florida have given their final approval for the launch of Shuttle Atlantis to proceed as planned, no sooner than August 27.

Atlantis will be carrying the P3/P4 solar array truss elements to the International Space Station (ISS) - the first assembly flight post-Columbia disaster - on a complex mission involving three spacewalks.

The bolts holding the KU band antenna in place in Atlantis' cargo bay proved to be the biggest topic of discussion at the FRR, with foam liberation concerns on the External Tank being diluted, following a clean STS-121 last month.

Evaluations on what to do with the bolts are still on-going, but not seriousness enough to affect the launch date - despite a previous NASA memo noting that a changeout of the bolts would lead to a rollback of the stack into the Vehicle Assembly Building (VAB).

'The longest thing we talked about wasn't the foam,' said Shuttle manager Wayne Hale. 'It was about the famous bolts that were found on the KU antenna. This is a real success story, an example of improving safety on board the Space Shuttle.

'Some 25 or 30 years ago a mistake was made in the design of this particular component, in the way this antenna is bolted on the orbiter. For the last 25 years we've been flying with these thread fasteners - these bolts that barely have a thread or two that holds them on. That is not good engineering practise.

'We had an exhaustive review - which is still ongoing - looking at all the thread fasteners on the orbiters and we found that the bolts weren't long enough. That is not where we want to be. So we changed the bolts out on Discovery and Endeavour.

NASA is evaluating whether they need to change the bolts out on Atlantis at the pad - allowing her to fly without any engineering being required on the antenna. Any work would have to be undertaken with great care, so as not to damage the nearby payload.

'On Atlantis the access very difficult, so we are doing more work to see how much risk is involved with changing those bolts out.'

'I think it's likely we'll change those bolts out, but the analysis is still ongoing,' added Hale.

'This is a normal day in the life of the Space Shuttle and I expect them to go on over the life of the Shuttle.

'All in all the team has worked very hard. We have 17,000 people working around the country on the Space Shuttle program and we're ready to go forward with the completion of a few last items and we aim to be back here on August 27 and hope mother nature will cooperate with us for an on-time launch on Sunday afternoon.'

Dissenting opinion was still in evidence at the FRR, but as with STS-121's meeting, this was encouraged, to ensure no stones were left unturned.

"It was an honor to work with this team, a thrill to see another FRR," said NASA Administrator Michael Griffin. "It was a great review, and I look forward to a great launch."

"The teams have done a great job of getting us here," added Associate Administrator for Space Operations Bill Gerstenmaier, who chaired the Flight Readiness Review. "We still have some minor open work in front of us. We look forward to the return to assembly".

[GioFX]

Da Spaceflightnow.com:

Atlantis crew arrives as countdown begins early

BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: August 24, 2006

The shuttle Atlantis' astronauts flew to Florida today to prepare for launch Sunday on a long-awaited flight to restart space station assembly. With forecasters predicting a 70 percent chance of good weather, liftoff from pad 39B is targeted for 4:30 p.m. Sunday.

"I hope you can tell by the smiles on our faces that we're very, very happy to finally be here in Florida to start the launch countdown," Commander Brent Jett told reporters at the shuttle runway. "Now there's been a lot of talk in the press lately about NASA being 'back' and I think we would all certainly agree with that talk. But we have a saying back in Texas that it's time to 'walk the walk.' Speaking for myself and my fellow crewmates, I can assure you we are ready for the challenge and we are anxious to restart the station assembly sequence. All we need is a little good weather Sunday and we'll be out of here."

Jett and his crewmates - pilot Chris Ferguson, Joe Tanner, Dan Burbank, Heidemarie Stefanyshyn-Piper and Canadian astronaut Steve MacLean - plan to spend the next two days reviewing their flight plan and relaxing before strapping in for launch Sunday.

Forecasters are predicting a 70 percent chance of acceptable weather Sunday, improving to 80 percent "go" Monday and Tuesday. NASA's launch strategy calls for back-to-back launch tries Sunday and Monday, then two more back-to-back tries Wednesday and Thursday to give four launch attempts in five days. Three more launch opportunities are available between then and the end of the launch window on Sept. 7.

While the afternoon weather is expected to be favorable this weekend, forecasters predict afternoon thunderstorms Friday and Saturday. As a result, the launch team moved up the start of Atlantis' countdown from 6 p.m. to noon today to give engineers a better chance for loading on-board oxygen and hydrogen for the shuttle's electricity producing fuel cells.

A hold at the T-minus 19 hour mark that normally lasts just four hours will be lengthened to 10 hours to make up for the early start of the countdown. When the count resumes at 2 a.m. Saturday, all subsequent activities will be synched up with the original schedule.

The goal of the 116th shuttle mission is to deliver and install a $372 million set of solar arrays and a complex rotary joint on the international space station, a complex job requiring back-to-back spacewalks, dual robot arm operations and tight coordination with flight controllers in Houston. It is the first in a series of assembly flights that rank as the most complex ever attempted by NASA.

Station assembly has been on hold since the Feb. 1, 2003, loss of the shuttle Columbia but with a successful test flight last month, NASA managers are counting on Atlantis' mission to restart the assembly sequence and clear the way for more frequent shuttle launchings.

"It's been six years since our payload has been at Kennedy," MacLean said. "It's been four years since Atlantis has been in preparation (for launch) and for us as a crew, it's been four and a half years as well. And finally, on Sunday, we're going to get to walk out to the pad for launch.

"For me, walking out to the pad on Sunday will be much like walking into an Olympic stadium for your athletic event. Many countries will be participating in a spirit of international cooperation and our families and our friends who believe in what we do will be in the front seats of the stadium. So I invite you all to watch what we do over the next week. It will be exciting. It's complex what we do, it's not easy. But with a team like this that I've been working with for the last four years and especially with the focus and dedication of the teams on the ground, I promise you we'll bring home a gold medal."

[GioFX]

Da NasaSpaceFlight.com:

NASA seeks Shuttle exhaust waiver

By Joseph O. Boggi, 8/24/2006 6:32:00 PM

A waiver has been requested by Space Shuttle engineers, ahead of Atlantis' launch on STS-115 this weekend, to mitigate risk associated with Space Shuttle Main Engine (SSME) exhaust in the event of the orbiter's computers issuing a shutdown after engine ignition on the pad.

The rationale is based on the risk of Hydrogen in the air - which could cause an explosion in certain conditions.

At T-6.6 seconds, the three SSMEs ignite in sequence. In the event of - for example one SSME failing to reach full power - the orbiter's computers signal for shutdown - that can leave Hydrogen in the air around the aft of the vehicle. If the presence of Hydrogen is of a volume of four percent or higher, combining with Oxygen, it can be a combustion source.

Recently, NASA Marshall Space Flight Center (MSFC) issued a waiver for the system that deals with Unburned Hydrogen. This issue of backflow of Hydrogen appears to remain a problem based on this waiver, only issued for STS-115.

'With urgent engine shutdown, the hydrogen in the air must be dispersed or burned to prevent a fire or explosion on the pad,' noted the document. 'This led to a Hydrogen 'burn off ' system for the following situations.'
1. On pad SSME start sequence. 2. Normal On pad SSME firing. 3. FRF Shutdown. 4. On pad abort shutdown.

However, a Hydrogen Burn Off Igniter (HBOI) system is not available for shutdowns late in the firing sequence, hence the need for a waiver. Numbers three and four are not covered by the HBOI.

HBOIs are activated at T-10 seconds and burn for 8 +5/-0 seconds. Based on that burn time, the current Hydrogen Burn Off System is not be active during a late SSME abort situation.

During this later phase, the Hydrogen that is not burned in the combustion chamber of the SSMEs will mix with atmospheric Oxygen to be consumed in the plume flame. This burning of Hydrogen in the exhaust plume flame continues until the Hydrogen concentration is below levels that will cause them to burn, thus the SSMEs themselves act as the Hydrogen burn off igniters.

Again, if the shutdown occurred earlier in the sequence, the HBOIs would have burned the excess hydrogen, keeping it from exploding. However, the HBOI does not work this late in the sequence as noted in the concerns.

Speculation has considered that a computer simulation still recommends that the HBOI will work during late shutdowns. There has been no report of damage, to the contrary, the report notes more than 1250 late shutdowns on the test stand without detonation.

The waiver request itself only notes that since the HBOI does not work late in the sequence, a waiver is needed. It does not go into why the waiver has become an issue now.

The intent of the HBOI requirement is being fulfilled by the SSMEs and other methods, such as Helium being pumped in to decrease the temperature and purge the Hydrogen. If Hydrogen concentrations are high the Firex sensors alarm - and pump in more water. This eliminates ignition sources by cooling surfaces below Hydrogen auto ignition temperatures. Hydrogen is quickly dispersed and concentrations fall below flammable levels (less than four percent).

The waiver request goes on to say that the permanent fix is to 'fulfil or rewrite the requirement.' Fulfilling the requirement would enable the HBOI system to continue late in the sequence. Rewriting the requirement would essentially make this waiver permanent. The issue of flammable Hydrogen concentrations and detonations late in the sequence would be handled by the SSMEs, Firex, Helium and dispersion into the air until Hydrogen concentrations are less than four percent.

Looking at the diagram to the left (click to enlarge), before the SSMEs ignite, hundreds of thousands of gallons of water (flame hole water), and the HBOIs are working to deal with the impending build up of Hydrogen.

To the left of the diagram, the ROFI Fire Command refers to the start of the HBOI system. Looking at the center of the diagram, typical burn and maximum burn are referring to the HBOI system. That ends at T+3 at best.

Looking to the right of the diagram, the Helium purges, Firex sensor alarm with subsequent additional water deluge (separate from the flame hole water at T-10 seconds) and the burning of the Hydrogen in the SSME exhaust takes care of the issue of elevated levels of hydrogen and possible explosion. The waiver seeks approval for this system.

Currently, flight rules require the continued burning of the HBOI system to function throughout this critical time.

Proper disposition of unburned Hydrogen in the SSME exhaust is a critical event. It carries the possibility of fire and explosion on the pad in the face of a late shutdown of the SSMEs.

However, as already noted, with thee 1250-plus test stand events - and no detonations occurring - it remains unclear and unsupported for this waiver to become permanent.

[Octane]

in questi casi non sarebbe anche possibile chiudere il flusso del comburente 1/4 o 1/2 secondo dopo il cutoff dell'idrogeno? In questo caso il combustibile residuo verrebbe bruciato il maniera "sicura" (oppure come hanno detto pompare gas inerti come elio o azoto per diluire/disperdere l'idrogeno residuo) ed arrivare sotto la concentrazione critica per il rischio esplosioni..

[GioFX]

Da Spaceflightnow.com:

Lightning delays Atlantis launch a day

BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: August 26, 2006

The lightning bolt that hit launch pad 39B Friday was one of the most powerful on record at the Kennedy Space Center, sending some 100,000 amps of current through the lightning protection system, officials said today. While the lightning protection system worked, shielding the shuttle Atlantis from a direct hit, engineers are concerned about induced currents that showed up in a brief spike in one of the shuttle's main circuits and another in a launch pad pyrotechnic system.


A bolt of lightning hits launch pad 39B on Friday. Credit: NASA-KSC

The spike in the shuttle electrical system was very small and within allowable limits. But no such spikes were expected, an official said, prompting engineers to question whether it might have caused any problems.

At the same time, telemetry indicated a spike in the circuitry associated with a pyrotechnic device that releases a hydrogen vent arm from the side of the shuttle's external tank at liftoff. Engineers inspecting the pad later reported a burning smell in the area of the gaseous hydrogen vent arm, but no obvious signs of damage were seen.

LeRoy Cain, chairman of NASA's Mission Management Team and director of shuttle integration at the Kennedy Space Center, delayed Atlantis' launch for at least 24 hours, from Sunday to Monday at 4:04:18 p.m., to give engineers time to inspect the vent arm system and to carry out additional tests and analyses. The forecast Monday and Tuesday is 80 percent "go."

The MMT will meet again at 10 a.m. Sunday to hear an update from the engineering community and to make a decision about whether to proceed to launch Monday or order an additional delay. As of this writing, it's not at all clear how that discussion might go.

Video of the lightning strike at pad 39B showed a large bolt hitting the mast atop the shuttle gantry that anchors the pad's lightning protection system. The shuttle wasn't hit and other than the slight 20-millisecond spike in the shuttle electrical bus, and the concern about the hydrogen pyrotechnic device, there are no other known problems.

"I did press pretty hard to see if it made sense in any way, shape or form to reconvene the team later today to attempt to see if we might be able to still have a viable launch opportunity tomorrow," Cain said. "And based on everything I heard, it was pretty clear to me that we need to let the folks go off and look at their data. So that's what we're going to do.

"We have a launch period here that allows us to go do that. We need to make sure we have a good ground and flight system. So the mission management team will reconvene tomorrow morning at 10 a.m. and we'll see where we are."

The goal of the 116th shuttle mission is to deliver a $372 million solar array truss segment to the international space station, a complex assembly task requiring three spacewalks to complete.

The shuttle's launch window, based on a requirement to launch in daylight and to avoid conflict with a Russian Soyuz launch, runs through Sept. 7. Atlantis' fuel cell system has enough on-board liquid oxygen and hydrogen for launch attempts Monday, Tuesday and Wednesday, although NASA does not usually make three attempts in a row.

After that, NASA managers would have to discuss a variety of options based on when the shuttle's fuel cell supplies would need to be topped off to preserve the option of extending the mission in orbit if necessary. Before today's scrub, NASA's launch strategy called for seven launch tries between Sunday and Sept. 7.

[GioFX]

Originariamente inviato da Octane

in questi casi non sarebbe anche possibile chiudere il flusso del comburente 1/4 o 1/2 secondo dopo il cutoff dell'idrogeno? In questo caso il combustibile residuo verrebbe bruciato il maniera "sicura" (oppure come hanno detto pompare gas inerti come elio o azoto per diluire/disperdere l'idrogeno residuo) ed arrivare sotto la concentrazione critica per il rischio esplosioni..

Non è possibile chiudere il flusso dell'ossigeno indipendentemente da quello dell'idrogeno, e cmq non si può nemmeno rischiare di creare un'atmosfera di ossigeno oltre una certa soglia, troppo pericoloso.