Why is the orbiter not placed on the Orbiter Transporter System when it is taken off of the mate/demate device at KSC? Was the MDD not designed to lower the orbiter with enough precision? Thanks.
Quote from: mjp25 on 10/06/2009 10:49 pmWhy is the orbiter not placed on the Orbiter Transporter System when it is taken off of the mate/demate device at KSC? Was the MDD not designed to lower the orbiter with enough precision? Thanks.The wheels have to be replaced anyway after a flight, it is faster to just tow it to the OPF.Before they got the Orbiter Transporter System the orbiters were towed during rollover too.
Edit: OK I just read on another post the cart was built for a long tow at Vandenburg. This almost makes sense, bearing temps or something might go out of specs for a long tow -- even then I don't see what is wrong with a long tow. But why then move the darn thing to KSC and use it instead of just towing to the VAB for stacking.
Quote from: Danny Dot on 10/07/2009 12:47 amEdit: OK I just read on another post the cart was built for a long tow at Vandenburg. This almost makes sense, bearing temps or something might go out of specs for a long tow -- even then I don't see what is wrong with a long tow. But why then move the darn thing to KSC and use it instead of just towing to the VAB for stacking.The "tow" route was hilly. Also the OTS allows for the gear to be retracted in a better facility
Edit: Why was there a need to tow on hilly terrain at Vandie? Sounds like a really bad place for shuttle OPS is there was not enough room to avoid hilly terrain. Even then, we have machines called "earth moving equipment" to level a road bed.
You haven't been to VAFB. Launch pads were in canyons. The tow route was more than 5 (maybe twenty) miles. The OMCF was on the north base and SLC-6 was on the south base.
Quote from: Danny Dot on 10/07/2009 01:58 amEdit: Why was there a need to tow on hilly terrain at Vandie? Sounds like a really bad place for shuttle OPS is there was not enough room to avoid hilly terrain. Even then, we have machines called "earth moving equipment" to level a road bed. You haven't been to VAFB. Launch pads were in canyons. The tow route was more than 5 (maybe twenty) miles. The OMCF was on the north base and SLC-6 was on the south base.
Quote from: K466 on 10/06/2009 11:19 pmQuote from: mjp25 on 10/06/2009 10:49 pmWhy is the orbiter not placed on the Orbiter Transporter System when it is taken off of the mate/demate device at KSC? Was the MDD not designed to lower the orbiter with enough precision? Thanks.The wheels have to be replaced anyway after a flight, it is faster to just tow it to the OPF.Before they got the Orbiter Transporter System the orbiters were towed during rollover too.You meant to say tires didn't you. The brakes were redesigned in about 1995 to allow for multiple uses. The old brakes broke up with a single use and tended to stick and what not. Really, really bad brakes. You couldn't use them, let up, then use them again. The pads would fracture at the first use and then when released, fractured pieces of brake pad would do nasty things to the brake assembly with the second application. They were an accident ready to happen and NASA fixed them. They also added the drag chute for crew safety at about this time.Danny Deger
With the SSME having LO2 and LH as fuel, when the engines are first started, is it with the Liquid or gaseous O2 and H. I was just wondering how it is vaporized before the engines are started or is it liquid when it ignites and during the flight?
And when the tank seperates on orbit does the doors seal the same as landing gear doors (Do they come down) or do they slide over to cover the connection point?
What if it failed to close?
Why does it take 1 week normally from the time the shuttle is connected to the Tank and Boosters in the VAB to roll it out? Once connected what tasks do they go through? Are there many, or just a few but are time consuming?
Quote from: brettreds2k on 10/08/2009 06:34 pmAnd when the tank seperates on orbit does the doors seal the same as landing gear doors (Do they come down) or do they slide over to cover the connection point?The doors are hinged on the inboard side, and after ET sep they flip 180 degrees to close.http://spaceflight.nasa.gov/shuttle/reference/shutref/orbiter/sep/umbdoors.htmlPhoto here:http://mediaarchive.ksc.nasa.gov/detail.cfm?mediaid=43554QuoteWhat if it failed to close? The doors can be closed manually via EVA. The area around the doors is (just barely) reachable by an astronaut in a foot restraint on the tip of the OBSS at the end of the RMS.If the doors can't be closed at all, LOV/C.
Quote from: Jorge on 10/08/2009 07:01 pmQuote from: brettreds2k on 10/08/2009 06:34 pmAnd when the tank seperates on orbit does the doors seal the same as landing gear doors (Do they come down) or do they slide over to cover the connection point?The doors are hinged on the inboard side, and after ET sep they flip 180 degrees to close.http://spaceflight.nasa.gov/shuttle/reference/shutref/orbiter/sep/umbdoors.htmlPhoto here:http://mediaarchive.ksc.nasa.gov/detail.cfm?mediaid=43554QuoteWhat if it failed to close? The doors can be closed manually via EVA. The area around the doors is (just barely) reachable by an astronaut in a foot restraint on the tip of the OBSS at the end of the RMS.If the doors can't be closed at all, LOV/C.Jorge; two follow-ups, if I may:(1) Regarding the manual closure of the ET umbilical doors, how is this done? Via a hand crank of some kind?
(2) Prior to the OBSS era, how would the EVA crewmember accomplish this without the extra reach provided by the boom? Thanks.
Quote from: Alpha Control on 10/08/2009 11:59 pmQuote from: Jorge on 10/08/2009 07:01 pmQuote from: brettreds2k on 10/08/2009 06:34 pmAnd when the tank seperates on orbit does the doors seal the same as landing gear doors (Do they come down) or do they slide over to cover the connection point?The doors are hinged on the inboard side, and after ET sep they flip 180 degrees to close.http://spaceflight.nasa.gov/shuttle/reference/shutref/orbiter/sep/umbdoors.htmlPhoto here:http://mediaarchive.ksc.nasa.gov/detail.cfm?mediaid=43554QuoteWhat if it failed to close? The doors can be closed manually via EVA. The area around the doors is (just barely) reachable by an astronaut in a foot restraint on the tip of the OBSS at the end of the RMS.If the doors can't be closed at all, LOV/C.Jorge; two follow-ups, if I may:(1) Regarding the manual closure of the ET umbilical doors, how is this done? Via a hand crank of some kind?There is no crank. What the crew would do depends on the failure mode. If centerline latch, open the latch manually and allow the motors to close the doors. There are two motors on each door, geared such that a jam in one motor cannot prevent the other motor from closing the door. An EVA astronaut could probably not close the door manually with a dual motor failure, but two independent failures like that is highly unlikely.Quote(2) Prior to the OBSS era, how would the EVA crewmember accomplish this without the extra reach provided by the boom? Thanks.Prior to the EVA, the crew would improvise a bolo using a bag full of clothes and an EVA safety tether. The EVA crewmember would translate to the aft end of the payload bay along the EVA slidewire on the sill, secure the tether end of the bolo to the slidewire, then sling the bolo such that the bag catches in the gap between the inboard elevon and the aft fuselage (this would likely take several attempts). The EVA cremember would then attach his own safety tether to the bolo, translate down the bolo to the elevon, then pull himself over the side. The umbilical doors are reachable from the underside of the elevon.This EVA was considered unlikely to work and consequently not taken seriously by most astronauts.Nevertheless, there was (and maybe still is) a high-fidelity mockup of the ET umbilical doors in the highbay of JSC building 9 for EVA training.