STS 129

[Moonwalker]

After 6 hours and 37 minutes, the spacewalk has been completed successfully.

It was the 228th U.S. EVA by the way, and the 134th in support of International Space Station assembly and maintenance.

[Moonwalker]

Foreman and Bresnik are performing their seond EVA right now. The EVA will be 30 minutes shorter than initially planned, due to the false pressure alarm once again.

Follow live at NASA TV: http://playlist.yahoo.com/makeplaylist.dll?id=1368163

[Moonwalker]

And EVA 2 has been completed more sucessfully than initially planned. The STS-129 crew was planning to deploy two Payload Attach Systems in three EVA's (this is where Express Logistics Carrier 4 will be installed). But they deployed three Payload Attach Systems in two EVA's. Robert Satcher asked Mission Control: "Do you have any more PAS's you need to deploy?" Capsule Communicator Steve Swanson replied: "Not on this station."

Repressurization is still underway. The crew awaits the two spacewalkers back aboard the ISS.



Next EVA: on Monday, 12:18 PM Central European Time (07:18 AM Eastern Standard Time).

[Moonwalker]

It's a must see. Below you'll find the HD downlink of flight day 3. Great footage (with sound) from inside the Shuttle's flight deck during ISS approach:

http://www.youtube.com/watch?v=iUobf1TpWuo

[Moonwalker]

And here is part two, which includes the docking as seen through the aft observation windows:

http://www.youtube.com/watch?v=xPfeJRosBqo

[spolvi]

Simply amazing!
I see they used a reticule in the window. For what and why in the SSM2007 there'isnt?
One more tecnical question: why the Shuttle perform a roll manoeuvere after cleared the tower?
Thank's, ciao.

[Moonwalker]

Simply amazing!
I see they used a reticule in the window. For what and why in the SSM2007 there'isnt?

That's still from the Apollo era. It's a rendezvous & docking aid called COAS - Crewmen Optical Alignment Sight.

http://eaglelander3d.com/missions/orbital/sts105-707-055_m.jpeg

One more tecnical question: why the Shuttle perform a roll manoeuvere after cleared the tower?
Thank's, ciao.

The Shuttle has to be oriented for the specific inclination of the ISS orbit, or whatever the mission objective of the Shuttle is in terms of payload/docking. If it would not roll put just pitch, it would head to the southern direction.

http://satcom.tonnarelli.com/pics/ShuttleInclinations.jpg

[spolvi]

OK I understud.
Tank's so much.
Undocking in progress now

[spolvi]

We have phisical separetion now

[spolvi]

Fly around in progress

[spolvi]

Sorry Moowalker, one more question:
the roll maneouvre is done with the engines or with the ailerons?

[Moonwalker]

Sorry Moowalker, one more question:
the roll maneouvre is done with the engines or with the ailerons?

It is done with the engines. After passing the launch tower, the speed of the Shuttle is still too slow and so the aerodyamic pressure on the aero surfaces as well.

By the way, there are three reasons why the Shuttle launches heads down:

1. For better communication between the Shuttle and the LCC - Launch Control Center (later into the ascent it turns heads up for better communication between the Shuttle and the TDRSS - Tracking Data Relay Satellite System)

2. The center of gravity of the entire stack is better controllable if the engines are located beneath the External Tank rather than on top (the thrust vector of the main engines is aimed at the center of gravity of the entire stack).

3. Heads down enables a slight angle of attack which puts the Shuttle in the supersonic shadow of the (big) External Tank. The structure of the Shuttle is quite sensitive. It's only .5 g more (3g all in all) than the load factor limit of a heavy passenger jet with gears and flaps retracted (2.5g). That's also why people and journalists are always wrong whenever they say and write that Challenger "exploded". Challenger broke apart as a result of aerodynamic stress due to the changed angle of attack after the External Tank broke apart (the propellant deflagrated quite fast; it was not an explosion). The accident happened 73 seconds after launch at a very high, supersonic speed. Any rapid change of the attitude can cause fatal stress on the vehicle, which we've seen on Challenger. Even fighter jets already broke apart during some maneuvers while flying supersonic. Those speeds have to be handled quite carefully.

[christra]

Sorry Moowalker, one more question:
the roll maneouvre is done with the engines or with the ailerons?

It is done with the engines. After passing the launch tower, the speed of the Shuttle is still too slow and so the aerodyamic pressure on the aero surfaces as well.
[..]

To precise that: It is done by gimbaling the SRB nozzles.

[bradleyjs]

Yes, the SRB's are gimbaled to control the roll -- as I understand it too.

[Moonwalker]

In short: it's both, the main engines as well as the SRB's which control not only the roll.

If we really want to precise that: it's six main engine and four SRB ATVC drivers (Ascent Thrust Vector Control), which we switch off on panel O17 at about T+01:00:00 in SSM2007 by the way, which get informations from the ascent thrust vector control portion of the flight control system, and which transmit these signals to the servoactuators of all 3 main engines and the 2 SRB's to control the entire trajectory from launch to SRB separation and main engine cut off.