What do the two triangles on the shuttle's HUD (see picture) represent? In the landing videos I've seen, they appear to be fixed at about 20 degrees glideslope; do the triangles indicate the ideal approach glideslope, or are they used for something else?
Quote from: SiameseCat on 01/02/2010 06:59 pmWhat do the two triangles on the shuttle's HUD (see picture) represent? In the landing videos I've seen, they appear to be fixed at about 20 degrees glideslope; do the triangles indicate the ideal approach glideslope, or are they used for something else?You're referring to the two horizontal triangles on the sides of the flight director bug? Those are also used as cues for preflare and final flare.
When the US signed an agreement with Russia on the ISS/Shuttle-Mir campaigns Russia offered to sell the US the Buran docking module for use on the STS, yet the US declined and instead developed their own derived from the existing US internal airlock.
The Buran docking system was capable of autonomous dockings yet the US airlock has to utilize a crew of at least five. If the US used the Buran docking system, could it have performed an autonomous docking (or at least lighten the crew work load)
and if so why was it not chosen?
I've seen a few posters on this site say something to the effect of "If a human were within 2 miles of the shuttle, the acustics would stop the human heart."
That is not quite correct. The US did purchase (and continues to purchase) the APAS docking mechanism developed for Buran, and simply adapted it to the existing US airlock and a new US-developed truss structure to form the Orbiter Docking System (ODS).
No. The Kurs system included with the Buran docking system was not compatible with the GNC systems on the shuttle and it would have taken a lot of time and money to make them compatible. The top-level program goal was a Shuttle-Mir docking in 1995 and it simply would not have been possible in the constrained budget environment.
The truss on the Buran docking system was not suitable for the shuttle orbiter's payload bay. Buran's trunnion system was designed to take loads in both the longeron and keel trunnions so their truss had only one longeron trunnion pin on each side, with pitch torque being absorbed through the keel. The orbiter's trunnion system is designed to take loads only through the longeron trunnions so it requires two longeron trunnion pins on each side.
The Buran docking system had a telescoping mount to extend the APAS mechanism above the payload bay moldline to improve clearance during docking. This was necessary for Buran since Kurs is not capable of as much precision during docking as a hand-flown docking, so a failed capture can results in much more dispersed bounce-off states. But the mount must retract before the payload bay doors can be closed, or the mechanism jettisoned via pyros. This was deemed unsafe.The systems in the Buran airlock were not compatible with existing orbiter systems and would have required extensive adaptation. (The systems needed to interface the orbiter power system with the APAS were extensive enough by themselves).
Quote from: Jorge on 01/07/2010 03:37 amNo. The Kurs system included with the Buran docking system was not compatible with the GNC systems on the shuttle and it would have taken a lot of time and money to make them compatible. The top-level program goal was a Shuttle-Mir docking in 1995 and it simply would not have been possible in the constrained budget environment.Was there ever any consideration for installing Kurs in between the Mir and ISS programs? I know that there was time in between the two to allow so, however perhaps the US built system could not accommodate it.
QuoteThe truss on the Buran docking system was not suitable for the shuttle orbiter's payload bay. Buran's trunnion system was designed to take loads in both the longeron and keel trunnions so their truss had only one longeron trunnion pin on each side, with pitch torque being absorbed through the keel. The orbiter's trunnion system is designed to take loads only through the longeron trunnions so it requires two longeron trunnion pins on each side.Hmm, this was not mentioned in the Energiya-Buran book that I am reading right now that mentioned the offer to sell the Buran Docking system to the US.
I would have assumed with the US shuttle that the crew would have taken over for the last part of docking, I suppose though that autonomous docking really is not needed on the STS since a crew is required anyhow.
A few small questions that I just thought about:1) If the ROFI sparklers failed to ignite at T-10, would this automatically cause an RSLS/GLS abort?2) how did they find out about the "twang" and impliment it into the launch sequence before STS-1?
1. yes2. General engineering sense. Push on a cantilevered object and it is going to move.
Did they simply underestimate how long it would take for the vehicle to return to vertical?
Quote from: nathan.moeller on 01/27/2010 01:29 pmDid they simply underestimate how long it would take for the vehicle to return to vertical?Wouldn't that have been caught prior to launch, during the FRF?http://www.myvideo.de/watch/2431762/Columbia_Flight_Readiness_Firing_FRF
You would think so, but it still leaves the question unanswered
Quote from: nathan.moeller on 01/27/2010 01:52 pmYou would think so, but it still leaves the question unanswered The question being, why didn't it launch at T-0?
The countdown was set up for SSME start at T-4. When the timing of the twang was determined (6 seconds), the countdown development was too far along to change, so SRB ignition was set at T+2 sec (the guidance has nothing to do with it) . The countdown was updated for later launches.
Regarding twang, does anyone have a graph of the displacement from one of the FRFs? Just curious what the cycles look like and how quickly it dissipates. Maybe a request for L2 Historical....