sjeyasin@axion.bt.co.uk (swaraj jeyasingh) (02/27/91)
From article <1991Feb22.223855.6112@news.arc.nasa.gov>, by yee@trident.arc.nasa.gov (Peter E. Yee): > > KSC SHUTTLE STATUS REPORT - FRIDAY, FEB. 22, 1991 - 9:30 a.m. > > STS-39/DoD - DISCOVERY (OV 103) - PAD A > LAUNCH - MARCH 1991 > > WORK IN PROGRESS: > - Evaluation of cracks in hinges for the external tank right and > left doors. ^^^^^ Anyone able to say what these are ? Hard to imagine what kind of doors a tank can have. Swaraj Jeyasingh sjeyasin@axion.bt.co.uk British Telecom Research Labs United Kingdom
lohof@buast5.bu.edu (Alan Lohof) (02/28/91)
>> STS-39/DoD - DISCOVERY (OV 103) - PAD A >> LAUNCH - MARCH 1991 >> >> WORK IN PROGRESS: >> - Evaluation of cracks in hinges for the external tank right and >> left doors. > ^^^^^ >Anyone able to say what these are ? Hard to imagine what kind of doors a tank >can have. > Recall how the orbiter is attached to the external tank? the orbiters engines get hydrogen and oxygen from the external tank via large pipes connecting the tank and the orbiter's underside. when the orbiter separates from the external tank, the pipes drop away from the valves on the orbiter and the above mentioned doors closed over the valves to seal the underside of the orbiter. The orbiters 'belly' must be sealed with the protective tiles for re-entry. A problem would arise if these valve hinges with the cracks would break away or be unable to close, thus exposing an area to the heat or re-entry. alan lohof lohof@buast5.bu.edu Boston Univ. Astro Dept.
gregc@cimage.com (Greg Cronau) (03/01/91)
In article <1991Feb27.123109.540@axion.bt.co.uk> sjeyasin@zaphod.axion.bt.co.uk writes: >From article <1991Feb22.223855.6112@news.arc.nasa.gov>, by yee@trident.arc.nasa.gov (Peter E. Yee): >> >> KSC SHUTTLE STATUS REPORT - FRIDAY, FEB. 22, 1991 - 9:30 a.m. >> >> STS-39/DoD - DISCOVERY (OV 103) - PAD A >> LAUNCH - MARCH 1991 >> >> WORK IN PROGRESS: >> - Evaluation of cracks in hinges for the external tank right and >> left doors. > ^^^^^ >Anyone able to say what these are ? Hard to imagine what kind of doors a tank >can have. > >Swaraj Jeyasingh sjeyasin@axion.bt.co.uk >British Telecom Research Labs >United Kingdom I believe these are for the 2 points on the aft underbelly of the shuttle where the External Tank support struts attach. After ET separation, these doors close over the attachment points. I would assume that the doors are covered with thermal tiles, similiar to the landing gear doors. gregc@cimage.com
john@newave.UUCP (John A. Weeks III) (03/03/91)
In article <1991Feb27.123109.540@axion.bt.co.uk> sjeyasin@zaphod.axion.bt.co.uk writes: > > - Evaluation of cracks in hinges for the external tank right and > > left doors. > Anyone able to say what these are ? Hard to imagine what kind of doors a > tank can have. There is a connection between the External Tank and the Shuttle. This connection supplies fuel from the ET in two lines (LOX and LH) and a number of telemetry cables. One of the fuel lines is 17" in diameter! After the ET is disconnected from the Shuttle, the hole in the bottom of the Shuttle has to be covered up with heat resistant tiles. Two doors are mounted on the bottom of the Shuttle. These doors close after ET seperation. Based on earlier discussions, it seems that the shuttle could obtain orbit with the doors open, but loss of vehicle and loss of crew would probably occur on re-entery. Thus, it is very important that these doors work properly. Cracks were found in three of the four door hinges while Discovery was being prepared for launch. There were three choices--fly as-is, replace the hinges, or install devices known as hinge-doublers. Replacing the hinges on the pad is fairly easy, but it is impossible to test the doors with the ET connected to the Shuttle. As a result, replacing the hinges means a roll-back and de-stacking, at a cost of nearly 2 months. Since one of the choices was fly as-is, flight preperations continued on Discovery until NASA decided on a solution. Yesterday NASA announced that it has choosen to replace the hinges, so Discovery will be rolled back. Next up is Atlantis and the Gamma Ray Observatory in April. -john- -- =============================================================================== John A. Weeks III (612) 942-6969 john@newave.mn.org NeWave Communications ...uunet!rosevax!tcnet!wd0gol!newave!john ===============================================================================
dave@viper.Lynx.MN.Org (David Messer) (03/06/91)
In article <1991Feb27.123109.540@axion.bt.co.uk> sjeyasin@zaphod.axion.bt.co.uk writes: >> - Evaluation of cracks in hinges for the external tank right and >> left doors. > ^^^^^ >Anyone able to say what these are ? Hard to imagine what kind of doors a tank >can have. These are the doors in the belly of the shuttle that allow connection to the external tank, not doors in the tank itself. Since these doors are in a high temperature area during reentry, it would be considered Not Good if they fell off or something during launch. -- The aliens are watching! They are | David Messer dave@Lynx.MN.Org -or- waiting for sentient life to evolve. | Lynx Data Systems ...!tcnet!viper!dave