Shuttle Q&A Part 5

• #1820 by Namechange User on 21 Mar, 2011 21:08
• No problem. 
• #1821 by Danny Dot on 22 Mar, 2011 01:35
• I think the usual term for the "cannon ball" is a mortar.  They are very common in chute deploy design.
• #1822 by Danny Dot on 22 Mar, 2011 01:45
• Quote from: OV-106 on 21 Mar, 2011 18:55

  Quote from: Zero-G on 21 Mar, 2011 18:33

  I seem to recall that on one Shuttle mission, the Orbiter's drag chute was not deployed on landing, as it had been decided against it, because a cover (or something similar) had fallen off earlier during the mission.
  Which mission was this?
  Had there also been other missions, where the drag chute was not deployed (on those missions equipped with a chute, of course)?
  Has there ever been a failure of the drag chute?
  

  
  As mentioned above it was STS-95.  The door fell off during SSME start.  There was some analysis and concern that the chute could have been damaged from the various thermal environments and so it was not used. 
  
  There aren't any other missions that I can recall where we just didn't use the chute and there have been no failures of the system as a whole (maybe some tears hear and there). 
  

  
  Didn't the door cause an SSME nozzle leak?
• #1823 by DaveS on 22 Mar, 2011 06:52
• Quote from: Danny Dot on 22 Mar, 2011 01:45

  Quote from: OV-106 on 21 Mar, 2011 18:55

  Quote from: Zero-G on 21 Mar, 2011 18:33

  I seem to recall that on one Shuttle mission, the Orbiter's drag chute was not deployed on landing, as it had been decided against it, because a cover (or something similar) had fallen off earlier during the mission.
  Which mission was this?
  Had there also been other missions, where the drag chute was not deployed (on those missions equipped with a chute, of course)?
  Has there ever been a failure of the drag chute?
  

  
  As mentioned above it was STS-95.  The door fell off during SSME start.  There was some analysis and concern that the chute could have been damaged from the various thermal environments and so it was not used. 
  
  There aren't any other missions that I can recall where we just didn't use the chute and there have been no failures of the system as a whole (maybe some tears hear and there). 
  

  
  Didn't the door cause an SSME nozzle leak?
  

  No. That would have been impossible since all it did was briefly contact a hatband on SSME#1.
  
  With a SSME nozzle leak you're probably thinking of STS-93 where a LOX post pin in SSME#3 was ejected at ignition, scraping against three nozzle coolant tubes which burst when they saw a increase in pressure.
• #1824 by Danny Dot on 22 Mar, 2011 15:22
• I used to love nozzle leaks in training sims.  Hundreds of feet per sec of performance loss that couldn't be modelled in the abort region determenator (ARD).
• #1825 by ChrisGebhardt on 22 Mar, 2011 16:03
• Quote from: Zero-G on 21 Mar, 2011 18:33

  I seem to recall that on one Shuttle mission, the Orbiter's drag chute was not deployed on landing, as it had been decided against it, because a cover (or something similar) had fallen off earlier during the mission.
  Which mission was this?
  Had there also been other missions, where the drag chute was not deployed (on those missions equipped with a chute, of course)?
  Has there ever been a failure of the drag chute?
  

  
  As mentioned, STS-95. IIRC, the following mission (STS-88) had the drag chute disabled while the problem was investigated.
• #1826 by JayP on 22 Mar, 2011 16:20
• Quote from: Zero-G on 21 Mar, 2011 18:33

  ...Has there ever been a failure of the drag chute?
  

  
  IIRC there was a flight a couple of years ago where a reefing line cutter fired prematurely and caused a couple of risers to fail and the reefing line hardware to become detached from the canopy. I can't remember the flight number though.
• #1827 by Jason1701 on 22 Mar, 2011 23:55
• How were STS flights numbered before Challenger? I'm confused with all the -D, -L, etc. designations.
• #1828 by Lee Jay on 23 Mar, 2011 00:03
• Quote from: Jason1701 on 22 Mar, 2011 23:55

  How were STS flights numbered before Challenger? I'm confused with all the -D, -L, etc. designations.
  

  
  First digit - planned year of flight (4 = 1984, for example), second digit = 1 for Florida and 2 for Vandenberg (you'll notice the 2 was never used as that site was decommissioned after Challenger), then the flights were "numbered" within each year by letter (A, B, C, .....).
  
  This wasn't a particularly popular approach.
• #1829 by Namechange User on 23 Mar, 2011 00:33
• Quote from: Lee Jay on 23 Mar, 2011 00:03

  Quote from: Jason1701 on 22 Mar, 2011 23:55

  How were STS flights numbered before Challenger? I'm confused with all the -D, -L, etc. designations.
  

  
  First digit - planned year of flight (4 = 1984, for example), second digit = 1 for Florida and 2 for Vandenberg (you'll notice the 2 was never used as that site was decommissioned after Challenger), then the flights were "numbered" within each year by letter (A, B, C, .....).
  
  This wasn't a particularly popular approach.
  

  
  True and I believe it was fiscal year not calander year.  Also STS-1 through 9 were numbered just how it is done now. 
• #1830 by Jorge on 23 Mar, 2011 02:22
• Quote from: WilliamPardy on 23 Mar, 2011 00:37

  Quote from: Jason1701 on 22 Mar, 2011 23:55

  How were STS flights numbered before Challenger? I'm confused with all the -D, -L, etc. designations.
  

  
  Done purely to avoid having an STS-13, by all accounts (known to me anyway).
  
  If they had kept that numbering system, I wonder what they would have done in 1994 when the single-digit fiscal years would have begun producing duplicate flight numbers.  Maybe they anticipated that the system would not outlive the incumbent Administrator who requested it?
  

  
  No, they would have avoided that issue by rolling over from STS-91x in FY89 to STS-101x in FY90.
• #1831 by DarkenedOne on 24 Mar, 2011 04:10
• I was wondering if anyone had explored the idea of creating a new shuttle orbiter that would interface with the current systems.
  
  There has been a great deal of advancement in the past 34 years, since the last space shuttle was built.  We have entirely new aerospace materials that are being widely used now including lithium aluminium and carbon fiber.  We have far better computers and monitors with fiber optic communications.  We have new materials for heat shields.  We have more advanced sensor systems for detecting problems. 
  
  I also heard from an engineer that worked on the shuttle that the technology exists that would eliminate the necessity of disassembling the SSME after every flight thus reducing labor considerably. 
  
  I am not saying we should spend the money to do it, but it is an intellectual curiosity of mine.
• #1832 by pathfinder_01 on 24 Mar, 2011 13:03
• Quote from: DarkenedOne on 24 Mar, 2011 04:10

  I was wondering if anyone had explored the idea of creating a new shuttle orbiter that would interface with the current systems.
  
  There has been a great deal of advancement in the past 34 years, since the last space shuttle was built.  We have entirely new aerospace materials that are being widely used now including lithium aluminium and carbon fiber.  We have far better computers and monitors with fiber optic communications.  We have new materials for heat shields.  We have more advanced sensor systems for detecting problems. 
  
  I also heard from an engineer that worked on the shuttle that the technology exists that would eliminate the necessity of disassembling the SSME after every flight thus reducing labor considerably. 
  
  I am not saying we should spend the money to do it, but it is an intellectual curiosity of mine.
  

  
  There was an OV200 concept in the 90ies(or very early 2000). They would have either built new Orbiters or done a major upgrade on them.
  
  The APU's which are very costly and dangerous would have been replaced by batteries and some of the shuttles hydraulics would have been replaced by electrical motors.
  
  If  a composite frame where used the shuttle's payload would have increased greatly.
  
  The idea got no traction and after the Columbia accident NASA spun off in a different direction.
  
  Major upgrades that did happen to the shuttle are:
  
  1. Replacing the Original cockpit instruments with a glass cockpit saving both mass and electrical power. The Seats were lighted in that upgrade ET fuel tank was also lightened several times over the years.
  
  2. Computer upgrades in the 90ies to bring the shuttle on par with a 486 computer.
  
  3. Addition of Parachutes for landing.
  
  4. A Orbiter extended duration kit that increased the amount of time the shuttle could stay in space. Originally Endeavor had it but it was removed from Endeavor and installed in Columbia(and later lost with it).They moved it to increase Endeavor's payload mass that it could carry to the station and gave it to Columbia because Columbia could not carry as much to the station as her sisters. In fact without the upgrades she received before her lost she could not have gotten to the ISS at all. Columbia for the most part would have focused on non ISS missions if not for the disaster but it could do a crew rotation and was planned to visit the ISS before her loss. Columbia could carry cargo to the ISS but it would have to be something small.
  
  5. Plus an upgrade to the life support to use a regenerative CO2 removal to reduce the amount of LIOH cartridges needed(so the shuttle could stay more time in space with the same number of cartages).
  
  6. A space station power system was also installed in all but Atlantis that allows the shuttle to us the ISS's power to extend the amount of time it can stay in space docked for a day or two.
  
  7. Even in terms of Mass if built Enterprise would have been the heaviest shuttle. Columbia was the Heaviest, Challenger was a few hundred pounds lighter than Columbia and Discovery and Atlantis are about 2,000 pounds lighter than Columbia(when built). Some of the lightness was due to the use of Thermal blankets(in some areas) instead of all tile(like Columbia) and some structural changes.(Challenger as a test bed(OV99) showed some areas where over built).
• #1833 by Danny Dot on 24 Mar, 2011 23:22
• I think there is a kit made to wire up the shuttle to do all of the manual only switch throws and button pushes.  Lowering the gear is probably number one on this list.
• #1834 by JayP on 25 Mar, 2011 01:45
• Quote from: Danny Dot on 24 Mar, 2011 23:22

  I think there is a kit made to wire up the shuttle to do all of the manual only switch throws and button pushes.  Lowering the gear is probably number one on this list.
  

  It's called the Remote Orbiter Kit. It is esentialy a cable bundle. One end connects to the racks in AV bay 3 on the mid deck. The other end connects directly to the switches that the crew would otherwise have to manually throw. The astronauts would physically open up the panels and directly connect the wires to the contacts on the back of the switches. The cable is stored on the ISS. It connects to the controls for the Payload Bay Doors, startup and shutdown of the APUs, deployment of the air data probes, deployment of the landing gear and deployment and jetison of the drag chute. I believe (but I can't confirm) that they would have to upload a special version of PASS to use it.
• #1835 by Jorge on 25 Mar, 2011 02:04
• Quote from: JayP on 25 Mar, 2011 01:45

  Quote from: Danny Dot on 24 Mar, 2011 23:22

  I think there is a kit made to wire up the shuttle to do all of the manual only switch throws and button pushes.  Lowering the gear is probably number one on this list.
  

  It's called the Remote Orbiter Kit.

  
  Actually called Remote Controlled Orbiter (RCO).
  
  

  Quote

  It is esentialy a cable bundle. One end connects to the racks in AV bay 3 on the mid deck.

  
  Specifically to the GCIL, which is the interface for ground commands.
  
  

  Quote

  The other end connects directly to the switches that the crew would otherwise have to manually throw. The astronauts would physically open up the panels and directly connect the wires to the contacts on the back of the switches. The cable is stored on the ISS. It connects to the controls for the Payload Bay Doors, startup and shutdown of the APUs, deployment of the air data probes, deployment of the landing gear and deployment and jetison of the drag chute.

  
  Don't think it controls the payload bay doors - those can be commanded through the crew displays (and therefore via DEU-equivalent commands from the ground). But it also controls the fuel cell reactant valves.
  
  The key point to get across, though, is that RCO only allows remote commanding of the particular switches required for an unmanned deorbit/landing. It is not a general purpose tool to allow an entire shuttle mission to be performed unmanned, just a Macgyver-esque hack to allow a shuttle crew stranded at ISS to attempt to return a damaged orbiter to allow the rescue orbiter to dock.
  
  

  Quote

  I believe (but I can't confirm) that they would have to upload a special version of PASS to use it.
  

  
  Used to. I think OI-32 fixed that.
• #1836 by Nomadd on 25 Mar, 2011 10:55
•  I take it the unmanned shuttle would have landed at Edwards?
• #1837 by arkaska on 25 Mar, 2011 11:08
• The only time RCO would be used was if the shuttle TPS would be ruled not safe for landing. In that case the most likely scenario is that the shuttle would be deorbited upside down and burn up in the atmosphere.
• #1838 by rdale on 25 Mar, 2011 11:31
• Quote from: Nomadd on 25 Mar, 2011 10:55

  I take it the unmanned shuttle would have landed at Edwards?
  

  
  Correct, that's what the plan has in it. But there also is plenty of talk that it'd be safer just to let it burn up over the Pacific this late in the game.
• #1839 by AnalogMan on 25 Mar, 2011 11:56
• Quote from: rdale on 25 Mar, 2011 11:31

  Quote from: Nomadd on 25 Mar, 2011 10:55

  I take it the unmanned shuttle would have landed at Edwards?
  

  
  Correct, that's what the plan has in it. But there also is plenty of talk that it'd be safer just to let it burn up over the Pacific this late in the game.
  

  
  My understanding was that Vandenberg was the preferred landing site (if there was to be one), having the lowest risk to the public or ground resources.