automated iss leak location system development status · automated iss leak location system ......

1

Automated ISS Leak Location System

Development Status

Dr. Eric Madaras

Todd Hong

Dr. Jialin Tian

Dr. Kornel Nagy

Dr. Cara Leckey

In Space Inspection Workshop

July 15-16, 2014

2

Outline

• Project background: “Pressurized Module Leak Detection and

Repair”

• Leak signals

• Ultrasonic Background Noise Test “UBNT” project status

• Leak location algorithm

• Steps Forward

2

3

09/12/07 3

0.0%

2.0%

4.0%

6.0%

8.0%

10.0%

12.0%

14.0%

16.0%

18.0%

Soyuz

Pro

gre

ss

SM

DC

1

SP

M

FG

B

RM

CM

Gs

MLM

CA

M

AP

M

MP

LM

JE

M L

M-P

S

Node 1

Node 3

HT

V

TC

S-s

Node 2

JE

M

Airlo

ck H

PG

C

TC

S-p

Lab M

odule

PM

A 2

PM

A 3

AT

V

PM

A 1

Cupola

PC

U

10

-ye

ar

MM

OD

Ris

k Baseline Risk (w/SM conformal SMDPs

only, no deployables)

Likelihood of Penetrating

Impact from MMOD

SM FGB N1 Lab

S

o

y

u

z

Soyuz N2

A

P

M

J

E

M

MP

LM

Loss of Crew – Emergency Depress

Consequences of Fast Leak

Loss of Vehicle – repair location unknown

or at least operations capability

Make-up Gas Depletion

PMA

A/L

3% with new shields

DC

Pro

gre

ss

10 Year (2007-2016) Cumulative Risk and

Informal Assessment of Consequences

Not all locations on

Module have equal

risk of damage.

Source: Studor, G., ISS Module Leak Detection and Location (MLDL) Operations Concept, Sep, 12, 2007.

4

Immediate Evacuation Function of station volume, crew O2 masks, etc.

T ime t o C rit ical Pressure Fo llowing Penet rat ion

ISS A ssembly C omplet e

0

1000

2000

3000

4000

5000

6000

7000

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

Hole Diameter (in)

Tim

e t

o C

riti

cal P

ressu

re (

sec)

Tim

e t

o 9

PS

I (n

o r

ep

ress g

ase

s)

seconds

Class 1 Alarm (0.44”)

(15min)

(30min)

(1hr 56min)

Rapid Depress Response of less that 6hr 11min Reserve Time means we are

looking to quickly detect and locate a large hole in a module about 0.2” to

less than 1.0” in diameter.

Note: ISS volume currently 20,000 cu ft; grows to 40,000 cu ft at AC.

Also, interior packing volume is higher than 70% assumed here

Reserve Time based on Hole Size (at Assembly Complete)

Reserve Time to Crew Hypoxia is a function of Hole size and ISS Gaseous Volume. The Reserve Time is a changing number as the ISS is updated.

ISS Module Leak Detection and Location

Requirements Drivers


5

• IRMA Watch Item #4669: “Pressurized Module Leak Detection and Repair” addresses a

requirement for leak mitigation due to MMOD damage including addressing ISS structural

integrity. As a step in the process, it specifies the requirements to characterize the ultrasonic

background noise in the ISS module as a step in the risk mitigation process.

• The ability to quickly identify, locate and repair leaks may reduce the risk of module loss and

significantly contribute to extend useful ISS life.

• Minimizing the loss of ISS resources increases efficiency of life support systems, reduces overall

resupply costs, and reduces operation impacts on science.

• Currently, there is a manual capability to locate slow leaks in the ISS utilizing airborne ultrasound

devices such as the Ultrasonic Leak Detector (ULD) (Narrowband) and the Russian AU-1

(Wideband research tool) and a Russian ULD. However, these devices have limitations, such as

line of sight (ISS pressure wall is generally blocked by structural components, avionics,

equipment racks and stowage).

• Years ago, we performed testing that demonstrated that structural ultrasonic noises generated by a

small leak (as small as 0.0625” diam.) can be readily detected throughout a space station module

and this methodology could form the basis of a comprehensive leak identification and location

system or impact detection system.

• The ISS authorized Phase I of the Ultrasonic Background Noise Tests (UBNT) project to integrate

and implement an on-orbit test to collect background structure-borne ultrasonic noise two ISS

Modules: the US Lab and Node 3.

Program Background

6

Leak Noise Spectra vs. Hole Size

(Node 1 STA)

1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

0 50 100 150 200 250 300 350 400 450 500

Am

pli

tude

(V)

Freq. (KHz)

Port Rack Sensor Set, 0.063" Smooth Hole @ Port Rack

Channel 1

Channel 2

Channel 3

Channel 4

1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

0 50 100 150 200 250 300 350 400 450 500

Am

pli

tude

(V)

Freq. (KHz)


Channel 1

Channel 2

Channel 3

Channel 4

1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

0 50 100 150 200 250 300 350 400 450 500

Am

pli

tude

(v)

Freq. (KHz)


Channel 1

Channel 2

Channel 3

Channel 4

• Signal increases with hole size

• Decreases with distance

• Most of the signal energy exists

between ~20-150KHz.

• Shows a slight peaking at ~60-70KHz

and at ~140KHz†

• How different the leak noise is from

the characteristics of the background

noise is important

†Bandwidth of transducers are 40KHz-350KHz

7

UBNT Hardware (Modified DIDS)

DIDS W = 1.71”

L = 1.72”

H = 0.82”

Weight = 1.2 Oz

= 34g

UBNT Transceiver W = 2.77”

L = 2.13”

H = 0.73”

Top Connector Dia = 0.25”

H =0.29”

Weight = 68g

Main Batteries (WLEIDS)

W = 2.12”

L = 1.20”

H = 0.97”

Pigtail

L =1.48”

Weight = 1.4 Oz

= 40g

UBNT Transducers (AE) Dia = 0.94” (w/protruding connector)

Dia = 0.75” (Base)

H = 0.78”

Weight = 1.31 OZ (each)

= 37 g

P/N: B225.5

Transducer Cables L ≈ 78.7”

Dia = 0.13

Weight = 1.0 OZ (each)

= 28 g

DIDS Extension Cable

with Antenna

L ≈ 80.1”

Weight = 1.5 OZ

= 42 g

P/N: IVC4181004-701

USB Cable (Type A to mini-B)

L ≈ 78.7”

Weight = 1.9 OZ

= 52 g

1GB

UBNT Micro-SD Card W = 0.61”

L = 0.38”

H = 0.03”

Weight < 1g

Model #: TS1GUSD

Each DIDS unit has 4 input channels for data acquisition of

the Acoustic Emission (AE) transducers.

8

Status of UBNT Phase 1A

1. UBNT hardware was manifested to ISS in Feb. 2011.

2. First UBNT sensor set was installed in Nov. 2012

3. First data take occurred on Dec. 12, 2012 (5700 measurements on one UBNT

set.)

4. Remaining UBNT sensors were installed by Feb. 1, 2013

5. First integrated data take using all seven sensor units occurred on May 14,

2013. (7700 measurements)

a. Summary data was downloaded on May 15, 2013.

b. Sets of full data were downloaded in June, 2013

6. Analyzed data and isolated ultrasonic and EMI type of noises.

7. Demonstrated the ability to locate noise sources in the US Lab from the

processed data using the Leak Location Algorithm.

9

UBNT Configuration in US Lab

2 1

3 4

2 1

3 4

2 1

3 4

1 4

=

2 3

1 4

2 3

UBNT S/N 1004

UBNT S/N 1005

UBNT S/N 1006

UBNT S/N 1035

UBNT S/N 1031

UBNT S/N 1003

UBNT S/N 1002

LAB1O01

LAB1OS0

UBNT Sensor Module

UBNT Transducer

UBNT Transducer Cable

AFT FWD

2 1

3 4

2 1

3 4

UBNT Antenna

10

2 1

3 4

1 4

2 3

1 4

2 3

UBNT Sensor Module

UBNT Transducer

AFT FWD

2 1

3 4

2 1

3 4

1.0E-06

1.0E-05

1.0E-04

1.0E-03

0 4 8 12 16 20 24

Sig

nal

Ener

gy (

V2-µ

s)

Time (hrs)

DIDS 1002, Signal Energy vs. Time

SE ch1

SE ch2

SE ch3

SE ch4

LAB1D2 AV-3

1.0E-06

1.0E-05

1.0E-04

1.0E-03

0 4 8 12 16 20 24

Sig

nal

Ener

gy (

V2-µ

s)

Time (hrs)


SE ch1

SE ch2

SE ch3

SE ch4

LAB1D4 CHeCS

1.0E-06

1.0E-05

1.0E-04

1.0E-03

0 4 8 12 16 20 24

Sig

nal

Ener

gy (

V2-µ

s)

Time (hrs)


SE ch1

SE ch2

SE ch3

SE ch4

LAB1O5 AVCO

1.0E-06

1.0E-05

1.0E-04

1.0E-03

0 4 8 12 16 20 24

Sig

nal

Ener

gy (

V2-µ

s)

Time (hrs)


SE ch1

SE ch2

SE ch3

SE ch4

SE ch1

SE ch2

SE ch3

SE ch4

LAB1O2 ExPRESS-1

1.0E-06

1.0E-05

1.0E-04

1.0E-03

0 4 8 12 16 20 24

Sig

nal

Ener

gy (

V2-µ

s)

Time (hrs)


SE ch1

SE ch2

SE ch3

SE ch4

AFT HATCHWAY

1.0E-06

1.0E-05

1.0E-04

1.0E-03

0 4 8 12 16 20 24

Sig

nal

Ener

gy (

V2-µ

s)

Time (hrs)


SE ch1

SE ch2

SE ch3

SE ch4

LAB1D6 ARS

1.0E-06

1.0E-05

1.0E-04

1.0E-03

0 4 8 12 16 20 24

Sig

nal

Ener

gy (

V2-µ

s)

Time (hrs)


SE ch1

SE ch2

SE ch3

SE ch4

FWD HATCHWAY

US LAB Test 2: Sensor Locations and Background Noise Responses (Summary Data)

STARBOARD

SIDE

DECK

SIDE

OVERHEAD

SIDE

PORT

SIDE

11

Background Signal Frequency Spectra

1.0E-08

1.0E-07

1.0E-06

1.0E-05

1.0E-04

1.0E-03

0 50 100 150 200 250 300 350 400 450 500

Am

pli

tude

(V)

Frequency (KHz)

UBNT S/N 1035, file 5748, Frequency

Channel 1

Channel 2

Channel 3

Channel 4

1.0E-08

1.0E-07

1.0E-06

1.0E-05

1.0E-04

1.0E-03

0 50 100 150 200 250 300 350 400 450 500

Am

pli

tude

(V)

Frequency (KHz)


Channel 1

Channel 2

Channel 3

Channel 4

Fwd Hatchway Overhead Rack #2

• Signals show significant energy

at low frequencies (<50KHz).

• Also indicate narrow bands of sound

from ~20KHz up to 150KHz.

12

Measured Signal Energy After Application of

50KHz 2-pole High Pass Filter

1.0E-08

1.0E-07

1.0E-06

1.0E-05

1.0E-04

1.0E-03

0 4 8 12 16 20 24

Sig

nal

Ener

gy (

V2µ

s)

Time (hrs)

Signal Energy After 50KHz 2-Pole Hi-Pass Filter

1002 SE ch1=

1002 SE ch2=

1002 SE ch3=

1002 SE ch4=

1005 SE ch1=

1005 SE ch2=

1005 SE ch3=

1005 SE ch4=

1006 SE ch1=

1006 SE ch2=

1006 SE ch3=

1006 SE ch4=

1035 SE ch1=

1035 SE ch2=

1035 SE ch3=

1035 SE ch4=

Transducer

key

13

Signal Frequency Spectra-

Before and After Filtering

1.0E-08

1.0E-07

1.0E-06

1.0E-05

1.0E-04

1.0E-03

0 50 100 150 200 250 300 350 400 450 500

Am

pli

tude

(V)

Frequency (KHz)

UBNT S/N 1005, file 9, Filtered Frequency

Channel 1

Channel 2

Channel 3

Channel 4

1.0E-08

1.0E-07

1.0E-06

1.0E-05

1.0E-04

1.0E-03

0 50 100 150 200 250 300 350 400 450 500

Am

pli

tude

(V)

Frequency (KHz)


Channel 1

Channel 2

Channel 3

Channel 4

Original Data from Overhead Rack #2 Filtered Data from Overhead Rack #2

14

Measured Signal Energy

After Removing Noise Sources

1.0E-08

1.0E-07

1.0E-06

1.0E-05

1.0E-04

1.0E-03

0 4 8 12 16 20 24

Sig

nal

Ener

gy

(V

2-µ

s)

Time (hrs.)

Signal Energy Measured in US Lab 1002 SE ch1

1002 SE ch2

1002 SE ch3

1002 SE ch4

1005 SE ch1

1005 SE ch2

1005 SE ch3

1005 SE ch4

1006 SE ch1

1006 SE ch2

1006 SE ch3

1006 SE ch4

1035 SE ch1

1035 SE ch2

1035 SE ch3

1035 SE ch4

Ultrasound peaks and EMI removed

15

Leak Location Algorithm

Two possible robust methods for an algorithm in a closed structure:

Use the matrix equation ,

where is a vector of L leak sources, is a vector of the amplitudes for D receiver locations, and is the acoustic transfer matrix. The acoustic transfer matrix was computed for the condition of a source of “unity” leak size

1.This matrix can be inverted to give a direct computation: . The

matrix can be inverted by using Singular Value Decomposition (SVD)

techniques to compute the inverse of the transfer matrix. Then will be the

distribution of leak locations that can be assess for the most likely location.

2.Perform a correlation between the vector values versus line by line to

create a “correlation” vector, where best correlation will be the most likely leak

location. This is the method that we have been using.

RD = A[ ]DLSL

RDA[ ]

DL

SL

SL = A[ ]DL

-1RD

SL

A[ ]DL

RD A[ ]DL

16

Computing the Acoustic Transfer Matrix

• Computational methods to compute the acoustic transfer matrix must be able to

compute the acoustic

1. direct field effects,

2. reverberant field effects, and

3. beam bending effects.

• Software that can compute the reverberant and beam bending effects in a complex

structure exists. Statistical Energy Analysis (SEA) and Energy FEM (E-FEM) are two

such commercially available methods. With modifications, both methods can also

handle the direct field.

• We have been using the E-FEM software with good results. It works directly with the

structural FEM model and once the correlation vector is computed, that vector can be

displayed on the FEM model to show where the most likely location of the leak is.

• In principle, this method can give us 100% coverage of an ISS module, without blind

spots. Since this is a noise locating algorithm, we used this method to help find the

location of the background signals, to display them on the FEM mesh, and to help

identify the hardware generating the noise.

17

Measured Signal Energy After Filtering

with Ultrasonic Noises Restored

1.0E-08

1.0E-07

1.0E-06

1.0E-05

1.0E-04

1.0E-03

0 4 8 12 16 20 24

Sig

nal

Ener

gy (

V2-µ

s)

Time (hrs.)

Signal Energy Measured in US Lab

1002 SE ch1

1002 SE ch2

1002 SE ch3

1002 SE ch4

1005 SE ch1

1005 SE ch2

1005 SE ch3

1005 SE ch4

1006 SE ch1

1006 SE ch2

1006 SE ch3

1006 SE ch4

1035 SE ch1

1035 SE ch2

1035 SE ch3

1035 SE ch4

18

Forward Aft

Overhead

Port

Starboard

Location of GLA

on LAB1OS1

panel in hallway

Location of GLA

on LAB1OP3

panel in hallway

US Lab FEM Model

Note: Location Estimates for Sounds Recorded

between 12 AM and 3 AM GMT on May 15, 2013

Crew was active during this period.

Noise Location Estimate for Sounds between 12 AM and 3 AM

19

FWD Hatch

Overhead

Port

Deck

Starboard

Noise Location Estimate for Sounds between 4 AM and 11 AM

Inter Module

Ventilation Ducts

Heat

Exchanger?

20

Next Steps

1. Finish UBNT Phase 1

a. Update software and hardware (from lessons learned on-orbit):

b. Acquire hardware for Node 3 and replace hardware for US Lab.

2. Assess leak location algorithm using ground resources (Hab Module at

MSFC and Node 1 STA at KSC) and the on-orbit background noise results

(requires extra hardware).

3. Acquire hardware for Russian SM and FGB.

a. This requires an agreement between Roscosmos and NASA plus

coordination between RSC Energia, Khurnichev, TsNIIMash, and

NASA.

b. Perform ground testing (MLM and SM mockups in Moscow).

c. Perform on-orbit testing in SM and FGB.

4. Develop the flight version of the leak location algorithm for each module.

5. Develop an integrated version of the software for the ISS as a whole.

21

Back-up Slides

22

Current MMOD Cumulative Annual Penetration Risk

Additional Progress on Nadir port of docking compartment more exposed to MMOD than aft port of Service Module

22


0.0%

0.5%

1.0%

1.5%

2.0%

2.5%

3.0%

Pro

gress

nad

ir

Soy

uz

Pro

gress

aft

Ser

vice

Mod

ule

Dock

ing

Com

partm

ent 1

FGB

CM

Gs

Lab

Node

1

TCS (s

tarb

oard

)

TCS (p

ort)

Airloc

k & H

PGCs

PM

A 2

PM

A 1

PM

A 3PCU

MM

OD

pen

etr

ati

on

ris

k f

or

1year

(2006)

23

UBNT System Overview

910Mhz

DIDS

Digital Wave - Piezoelectric AE Sensor: • Model B-225.5

• Frequency bandwidth: 50kHz - 400kHz

• Temperature range: -50°C to +100°C

• Dimensions: 0.625” diameter. x 0.8" H

• Connector type: Microdot

Sensor Cable

• Length: 2 Meters

Sensor Cable


DIDS Power Supply WLE L91 Battery Pack 2 – Energizer L91 AA batteries 3.0 VDC output (nominal)

Antenna/Data Cable


• SMA connector

• Teflon jacket

• Kynar heat shrink

910Mhz SSC

DIDS Receiver

connected to SSC

via USB

Power supply and DIDS sensor units attached to ISS Module pressure wall using velcro. AE sensors attached using pre-certified adhesives (see backup).

JSL File

Server

OCA/Ground

Cert

ifie

d E

the

rne

t ca

ble

NOTE: Diagram illustrates system configuration by ISS Module. No more than 7 DIDS sensor units will used in any ISS Module.

Principal

Investigator

(LaRC)

24 09/12/07

24

Crew laptop on ISS Server

DIDS Wireless

Sensor Units

DIDS Wireless

Receiver tethered to

crew laptop

Note: All Sensor

hardware is Internal

DIDS Wireless

Sensor Units

Leak Location System Concept

automated iss leak location system development status · automated iss leak location system ......

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