Author Topic: 121: Discovery at the pad update thread  (Read 62626 times)

Offline rdale

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Re: 121: Discovery at the pad update thread
« Reply #40 on: 05/30/2006 03:16 am »
July is not a big month for hurricane concerns.

Offline shuttlefan

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Re: 121: Discovery at the pad update thread
« Reply #41 on: 05/30/2006 03:35 am »
Do they close the pad this week to all non-essential personnel for storable propellant loading--about a 2-day operation?

Offline Jim

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Re: 121: Discovery at the pad update thread
« Reply #42 on: 05/30/2006 11:13 am »
Quote
shuttlefan - 29/5/2006  11:22 PM

Do they close the pad this week to all non-essential personnel for storable propellant loading--about a 2-day operation?

There are some pad clear times, when they make or break connections and when they flow propellants

Offline DaveS

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Re: 121: Discovery at the pad update thread
« Reply #43 on: 05/30/2006 11:28 am »
Seems like they have extended the GOX vent arm over the ET.

Anyone know why?
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Offline DaveS

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Re: 121: Discovery at the pad update thread
« Reply #44 on: 05/30/2006 11:37 am »
Now they have lowered the "beanie cap" over the ET.
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Offline shuttlefan

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Re: 121: Discovery at the pad update thread
« Reply #45 on: 05/30/2006 01:52 pm »
Perhaps it is to make the vehicle more sturdy because it will be slightly heavier once they load some of the hypergolic propellants onboard?

Offline Jim

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Re: 121: Discovery at the pad update thread
« Reply #46 on: 05/30/2006 02:39 pm »
Quote
shuttlefan - 30/5/2006  9:39 AM

Perhaps it is to make the vehicle more sturdy because it will be slightly heavier once they load some of the hypergolic propellants onboard?

There is no physical interface (except for soft ducts) between the beanie cap and the ET.  The hypergols are nothing compared to the ET load.  

They are probably doing a fit check

update:  The beanie cap  has been retracted

Offline DaveS

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Re: 121: Discovery at the pad update thread
« Reply #47 on: 05/31/2006 01:47 pm »
According to Shuttle Guy on SDC, hypergolic propellant loading preps are 2-3 days behind schedule and there's a problem with an SRB Integrated Electronics Assembly whcih could lead to a rollback to the VAB for replacement: http://uplink.space.com/showthreaded.php?Cat=&Board=missions&Number=508879&page=0&view=collapsed&sb=5&o=0&vc=1
"For Sardines, space is no problem!"
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Offline psloss

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Offline Chris Bergin

RE: 121: Discovery at the pad update thread
« Reply #49 on: 05/31/2006 04:50 pm »
Just waiting for an update on this issue myself. Personally, I want to hear from JSC Engineering who are in talks with USA over the issue.
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Offline shuttlefan

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RE: 121: Discovery at the pad update thread
« Reply #50 on: 05/31/2006 05:56 pm »
I just read that they consider it a minor issue and they just want to take a look at it.

Offline shuttlefan

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Re: 121: Discovery at the pad update thread
« Reply #51 on: 05/31/2006 06:00 pm »
If I recall correctly, I believe they have replaced Integrated Electronics Assemblies on the pad.... ;)

Offline mkirk

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RE: 121: Discovery at the pad update thread
« Reply #52 on: 05/31/2006 06:26 pm »

OKAY with all the talk of hypergolic laoding I will post this:

MORE THAN YOU WANTED TO KNOW ABOUT SPACE SHUTTLE HYPERGOLIC LOADING

The Hypergolic Propellant Loading Procedure Know as S0024 (pronounced “Sue 24") is designed to load Monomethyl Hydrazine (fuel) and Nitrogen Tetroxide (oxidizer) propellants into the RCS (reaction control system) and OMS (orbital maneuvering system) tanks.  The 44 RCS thrusters are used for attitude control of the orbiter and small velocity changes (usually less than 6 feet per second).  The two 6000 pound thrust OMS engines are used for orbital altitude and velocity changes.
 

During the procedure Hydrazine is loaded into the 3 Orbiter APU (auxiliary power units) fuel tanks and the 4 SRB HPU fuel tanks (2 units per booster).  The APUs provide the mechanical shaft power to operate the orbiter hydraulic pumps which in turn operate the main engine valves, thrust vector control system, aerodynamic surfaces, landing gear deploy, wheel brakes, and nose wheel steering.  The SRB HPUs are used to provide thrust vector control of the SRB nozzles (also called “rock” and “tilt”).

This is a brief rundown of the S0024 procedure.  Many tasks listed here actually occur in parallel.  For example the fueling of an SRB HPU, and OMS tank, and an APU may be occurring at the same time.

T + 0

  • S0024 Call to Stations
  • Safety and Facility walk downs
  • Configure LPS (launch processing system) consoles and Hot Spare consoles (i.e. backup consoles)
  • MEC (master events controller) power up
  • ECS (environmental control system) preparations for changeover from Air to GN2 (gaseous nitrogen) - This helps reduce fire hazard
  • SRB aft skirt purge
  • Fire personnel on standby
  • Pressurize the MLP (mobile launch platform)
  • Clear Non-Essential Personnel to Pad Perimeter fence
  • Power up GNC (guidance navigation and control) – this system provides commanding to the thrusters
  • Power up electrical busses
  • Conduct RCS Logic and Driver Command Tests – the systems are tested on alternate power sources

T + 6 Hours

  • Go for oxidizer (nitrogen tetroxide) loading
  • Establish oxidizer flow to RSS (rotating service structure) – this starts nitrogen tetroxide flow from the storage farm to the Pad
  • Perform oxidizer propellant sampling
  • FRCS (forward RCS) oxidizer loading
  • Crossfeed oxidizer loading
  • LOMS (left OMS) oxidizer loading
  • ROMS (right OMS) oxidizer loading
  • LRCS (aft left RCS) oxidizer loading
  • RRCS (aft right RCS) oxidizer loading
  • Purge and disconnect the oxidizer QDs (quick disconnects)
  • Oxidizer operations completed

Resume limited Pad access
Conduct Engineering walk down
APU console preparations – the APU consoles are configures in the launch control center

T + 28 Hours

  • Clear Pad for fuel (monomethyl hydrazine & anhydrous hydrazine) operations
  • Establish fuel flow to RSS (rotating service structure) – this starts hydrazine flow from the storage farm to the Pad via the cross country lines
  • Crossfeed fuel loading
  • LH SRB (left hand solid rocket booster) System A fuel load
  • APU 1, 2, & 3 Vent
  • APU 1, 2, & 3 Hydrazine loading
  • ROMS (right OMS) fuel loading
  • FRCS (forward RCS) fuel loading
  • LH SRB (left hand solid rocket booster) System B fuel load
  • LOMS (left OMS) fuel loading
  • RH SRB (right hand solid rocket booster) System A fuel load
  • RRCS (aft right RCS) fuel loading
  • RH SRB (right hand solid rocker booster) System B fuel load
  • Purge and disconnect the fuel QDs (quick disconnects)
  • Waste removal from Pad to Fuel Farm
  • Fuel clean up
  • Toxic vapor checks
  • Allow Pad access
  • O2 concentration checks
  • Ingress Crew Compartment
  • Configure electrical power and DPS (data processing system)
  • MLP securing

The S0024 procedure is completed about 48-50 hours from operation start (not including pre-operation setups).  The attached picture shows one of the hypergolic storage facilities and it's relative location to the Pad.  The other facility is on the opposite side of the Pad.

Mark Kirkman

 

 

 

Mark Kirkman

Offline Mark Dave

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Re: 121: Discovery at the pad update thread
« Reply #53 on: 05/31/2006 07:39 pm »
I read once that one of the upgrades to the orbiter was the elimination of the hypergolic fuel and replace that with a safer fuel that isn't as dangerous.

Offline mkirk

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RE: 121: Discovery at the pad update thread
« Reply #54 on: 06/01/2006 12:00 am »
Here is a shuttle update from KSC PAO

Mission: STS-121 - 18th International Space Station Flight (ULF1.1) -
Multi-Purpose Logistics Module
Vehicle: Discovery (OV-103)
Location: Launch Pad 39B
Launch Date: Launch Processing Window July 1-19, 2006
Launch Pad: 39B
Crew: Lindsey, Kelly, Sellers, Fossum, Nowak, Wilson and Reiter
Inclination/Orbit Altitude: 51.6 degrees/122 nautical miles

Over the holiday weekend, technicians performed no significant
processing work at the launch pad. Connections and leak checks of
auxiliary power units No. 1, 2 and 3 are complete.

Thursday morning, workers will begin prelaunch propellant loading of
the monomethyl hydrazine and nitrogen tetroxide for the forward
reaction control system and the orbital maneuvering system pods.
Reaction control system quick disconnect mates and interface leak
checks were completed May 26.

Following payload installation into the payload bay last week, the
payload bay and payload changeout room doors were closed on Friday.


Mark Kirkman
Mark Kirkman

Offline mkirk

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RE: 121: Discovery at the pad update thread
« Reply #55 on: 06/01/2006 12:13 am »
Here are a couple of additional comments for those who didn’t pick this up from today’s briefing.

It looks like the hypergol loading will be broken up into segments.  This is not unusual, operational considerations often force modifications such as this.

Since the Left Hand SRB (Solid Rocket Booster) tripped its main bus power supply (from main B to C) the KSC folks do not want to power up the SRBs for hypergol loading of the SRB hydraulic power units until they understand the cause of the switch in electrical power sources.  

So the plan as of now is to load the Orbiter hypergol propellants now and work the SRBs later.  This will begin with the loading of the forward RCS (reference my earlier post on the typical loading procedure).

Mark Kirkman
Mark Kirkman

Offline galileo

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Re: 121: Discovery at the pad update thread
« Reply #56 on: 06/01/2006 12:18 am »
Quote
DaveS - 30/5/2006  6:24 AM

Now they have lowered the "beanie cap" over the ET.

They extended the GVA due to a PR that was picked up during rollout for a bird that landed on the composite nose cone.  The GVA is the only access we have at the pad to the nose cone and the GVA was being repaired over the last week so there was a long delay before inspections could be performed.  The pictures i saw this morning showed extremely thin scratches and no repair is required, "fly-as-is".

The GVA has been retracted to its normal stowed position until S0007.

Offline psloss

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Re: 121: Discovery at the pad update thread
« Reply #57 on: 06/01/2006 12:27 am »
Thanks for giving us the details!

Offline Chris Bergin

RE: 121: Discovery at the pad update thread
« Reply #58 on: 06/01/2006 01:44 pm »
Any of our United Space Alliance people got an update on troubleshooting last night?
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Offline shuttlefan

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RE: 121: Discovery at the pad update thread
« Reply #59 on: 06/01/2006 01:55 pm »
Thanks very much for the schedule for hypergolic propellant loading-nice and detailed! :)  :)  :)

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