NASA SGSLR Power and Lightning Protection System

H. Donovan1, J. McGarry

2 , A. Nelson

1, D. Patterson

1, F. Hall

1, P. Christopoulos

1, D. Panek

1, E. Ridge

1

1 KBRwyle Technology Solutions LLC, Lanham, MD, USA

2 NASA Goddard Space Flight Center, Greenbelt, MD, USA

Abstract: The Space Geodesy Satellite Laser Ranging (SGSLR) Lightning Protection System will use a multi-tiered system to protect the station s sensitive electronic equipment and instrumentation. Without such protection, a ranging system can incur extensive electronic equipment damage and/or lengthy operational interruptions. As an example, on June 14, 2015, severe lightning occurred at the Goddard Space

Flight Center (GSFC), location of the SGSLR Prototype, the Next Generation Satellite Laser Ranging system (NGSLR). When attempting to power on the various equipment of the NGSLR the following workday, it was realized that the system suffered significant damage to almost all major subsystems: meteorological, communications, timing, aircraft avoidance, optical bench, computer, security, and Heating

Ventilation Air Conditioning (HVAC). The adjacent Mobile Laser Ranging System (MOBLAS) 7 station system incurred damage as well because of common signal paths between the systems. Another example of severe lightning damage occurred this year at the McDonald Laser Ranging System (MLRS) in Fort Davis, Texas, US. As a result of these incidents, a multi-tiered lightning protection system was

designed and has been implemented for the GSFC Goddard Geophysical and Astronomical Observatory (GGAO) SGSLR and will be installed at all of the SGSLR sites. System power, station grounding, and data and communications have all been addressed to greatly minimize the effects of a lightning strike and/or associated power surges. This poster describes the resulting new lightning protection system as it

is being installed at the SGSLR at the GGAO.

2019 ILRS Technical Workshop in Stuttgart, Germany

Data & Communications External Interfaces

HVAC 2HVAC 1

Anemometer

GPS Antenna

Meteorlogical Sensor

Fiber for monitoring status/control

HVAC Control

MASER

Ph

on

e a

nd

Inte

rnet

LHR

S M

ag

net

ron

Fir

e C

on

firm

ati

on

fo

r V

LBI

Plan for SGSLR

In Server Racks

In Shelter

FT

10

Mh

z a

nd

1 P

PS

*

SPPower Fence

FT

FT

FT

10 Mhz & 1 PPS

SP

Vaisala

SkyCamera

LHRS

ELIMINATE COPPER CONNECTIONS TO THE OUTSIDEData & Communication Diagram

FT

FT

FT

FT

FT

FT

FT

FT

SP

SP

SP

SP

SPFT

VLBI

FTLHRS Magnetron Fire Confirmation for VLBI

STALASBuilding

FT

FJB

Communication link with SGSLR

FJB

FT

Co

mm

un

ica

tio

n li

nk

wit

h S

GSL

R

To minimize damage

caused by lightning to

external data and coms

interfaces, SGSLR uses

fiber optic transceivers.

Data interfaces for the

LHRS, Pressure and

Temperature and

Humidity, sensors, Sky

Camera, Anemometer,

Horizontal Visibility and

Present Weather sensors,

GPS antenna and internet/

voice comms are all

optically coupled between

the sensor outside the

shelter and equipment

inside the shelter. Grounding, Counterpoise, and Air Terminals

The SGSLR uses a counterpoise

ground system. A heavy gauge

copper cable encircles the perimeter

of the Shelter and is buried beneath

the ground surface. Ground rods

were driven several feet into the earth

and placed every 2 meters, then cad

welded to heavy gauge copper cable.

On the top of the Shelter, a heavy

gauge braided copper cable was

placed around the roof parameter then

connected to the counterpoise. Air

terminals were placed at the four

corners of the roof and midway length

wise of the building. The ground field

was constructed to provide minimal

earth ground resistance with a goal of

no more than 5 ohms. Inside the

building individual heavy gauge

copper cables are connected directly

to ground bus bar in each equipment

rack then to a copper bus bar behind

the racks. The bus bar behind the

racks is then directly connected to the

counterpoise.

Lightning & Power Protection Equipment

Eaton 9PXM 12S 16K

Uninterruptable Power Supply

On June 14th, 2015, the NGSLR experienced a

lightning strike. Outside security cameras recorded

video of the storm as it passed over the system.

The storm was short and intense with heavy rain

and many lightning strikes. Though the security

system was damaged, video was able to be

extracted from the DVR. Heavy rains and lightning

began at 21:18 local time. At 21:35 local time the

NGSLR security cameras stopped functioning; it is

believed this is when the damaged occurred. The

image to the left is a frame from the security video

showing a lightning strike at the GSFC GGAO in the

background and the NGSLR in the foreground.

Image to the right is of the NGSLR.

The Lightning Strike at NGSLR

The SGSLR incoming power will be conditioned using

multiple systems. A suppression filter system using

thermally fused Metal Oxide Varistors (MOV) will

significantly reduce power spikes from lightning or other

equipment outside of the SGSLR. The suppression filter

system has Ethernet connectivity to communicate time

stamped events of magnitude and duration sags, surges,

dropouts, frequency, etc. as well as health of the

suppression system. The Uninterruptable Power

System (UPS) will further filter the incoming power and

compensate for power spikes, sags, surges, line

frequency changes and interruptions protecting the

equipment and instrumentation. The UPS has a

computer interface allowing monitoring of each of the 5

power modules. Power Distributions Units (PDU) are

used in each rack to prove power control and monitoring

for each piece of equipment. Power consumption can

be monitored to understand instrument health.

Equipment external to the SGSLR shelter such as the

Laser Hazard Reduction System (LHRS) and the

meteorological equipment will obtain power via the UPS

and PDUs receiving protection from incoming power

disturbances. MOV surge suppressors will be

connected to the power lines at the shelter interface and

the equipment interface to minimize the effects of

lightning disturbances along the external equipment

power line.

Rack 3

Three Phase

Transformer

Power

Fence

Counterpoise

Air Terminal

1

Th

ree p

hase f

eed

with

ne

utr

al an

d

safe

ty g

roun

d

SP

In Shelter

HVAC 1

Rack 2

1 Five wire, three phase feed (A, B, C) system with

neutral and ground isolated back to the tranformer.

2PDU units are used to provide, monitor and

control (ON/OFF) power.

3UPS unit is used to provide, monitor and control

(ON/OFF) conditioned power.

DRAWING NOTES

Rack 4

PDU 4

Laser

Motion Control

Rack 1

Computers

Dome Control

Electronics

Dome Backup

Battery

HVAC 2

UPS

SP

Breaker

box

Servo Digital

Controller

Range Control

Electronics

Laser Safety

Eqpt.

Networking

Eqpt.

Monitoring Eqpt.

Time and

Frequency (TFS)

Equipment

PDU 3PDU 2PDU 1

Earth Ground

Drawing D-828a

SP

JB Electrical Junction Box

Surge Protection

KEY

UPS

PDU

Uninterruptable Power Supply

Power Distribution Unit

Three phase feed (5 wire)

Three phase (5 wire)

Single phase

Conditioned single phase

Counterpoise (leads to ground field)

SPJB

SPJB

SPJB

SPJB

SPJB

SPJB

SP

GPS Antenna

Anemometer

TPH Sensor

HVP Sensor

SkyCamera

Aircraft Detect

2 2

3

2

2

SGSLR Power Distribution Protection

The lightning storm damaged 6 of the 9 NGSLR subsystems: Computer,

Meteorological, Time and Frequency, Safety, Shelter, and Optical Bench. Even

though the NGSLR equipment was connected to UPS, many components were still

damaged, and many beyond repair. These components were the Pseudo Operator

(POP) and Device Access Manager (DAM) computers, the Paroscientific MET4, the

TrueTime XL-DC time and frequency unit, the LHRS, the IO chassis, Heating

Ventilation Air Conditioning HVAC unit 2, security system monitor/DVR/outside

cameras, Risley prism controller, and telephones.

The lightning strike occurred near NGSLR causing a high voltage and current surge

that entered the system through multiple paths. External copper communications

lines for the telephones and internet are two likely paths as the associated

equipment was damaged beyond repair. The internet line was connected to a

Network Switch then to the VME Chassis and all were damaged. The VME based

POP and DAM computers share various serial and parallel communications cards

which connect to other equipment in NGSLR. The VME parallel interface were

connected to the IO Chassis, which in turn, connects to the LHRS Local Control

unit, both of which were damaged. The MOBLAS 7 LHRS, which was connected to

the NGSLR Local Control unit, was also damaged. The LHRS temperature control

unit located in the NGSLR shelter failed, as well as the temperature sensor for the

controller, which is located outside. The security camera system was connected to

two outdoor cameras and an HDTV monitor, all of which were damaged. The

compressor for the HVAC unit 2 failed along with a controller board power supply.

Equipment connected to the UPS systems did not receive damage.

Communications and data interfaces to the outside world were the primary cause.

STALAS

NETWORK SWITCH (LINK TO NASA INTRANET)

A Module B Module C Module D Module

T Z W

DELAY

OU

T

T Z W

DELAY

OU

T

T Z W

DELAY

OU

T

T Z W

DELAY

OU

T

PHILIPS

SCIENTIFICLRO Delay (6915 CFD)D

EL

AY

IN

OU

TO

UT

TT

L

1

2 4

3SECURITY DVR

Outside

CamerasInside

Cameras

MV

P

CO

NT

RO

LL

ER

S

J1 J2 J3 J4 J5 J6 J7 J8

J9 J10

10 MHz IN

CH1

J11 J12

J13 J14

CH1TTL NOT

CH2TTL NOT

CH3TTL NOT

CH0TTL

CH2 & CH3TTL NOT

CH2NIM

CH3NIM

CH0TTL NOT

RANGE GATE GENERATOR

JDB1 JDB4JDB2MSBC

JDB3LSB

CH0TTL

CH2TTL

CH3TTL

CH1TTL

SLR LASER (Photonics Industries)

LRO LASER (Northrop Grumman)

SCSI

I/O BOX

IO CHASSIS (IOC)

SLR START

SMATRIGGER (TTL) BNC

Hamamatsu MCPModel # R5916U-64

GPS TIME & FREQ. RECVR.TRUETIME XL-DC

ANT5 MHz5 MHz 10 MHz 10 MHz IRG-B1 PPS

SERIAL I/O

RS-232

2k OUT(NIM)

1 PPSOUT(NIM)

10 MHzIN

1 PPSIN

10 MHz OUT

2k OUT(TTL)

LASER FIRE

5 MHz5 MHz 10 MHz 10 MHz

COMPUTER CLOCK

SYNC INTERFACE (CCSI)In House Built Timing Box

ICC COMPUTER

IN

CONNECTION TYPE:

Analog*

10 MHz*

NIM*

TTL*

RS-232

Fiber Optic

Other

1

DISTRIBUTION AMP. SYMMETRICOM 6502

6502987654321 10

OUTPUT

GATING POWER

SUPPLY (GM150-20)

AMPLIFIER PHILLIPS SCIENTIFIC (774)

DISCRIMINATORTENNELEC (TC454)

INININ IN

OU

T

OU

T

OU

T

OU

T

1 2 3 4

High Voltage Power

Supply (Bertran 315)

DISCRIMINATORTENNELEC (TC454)

2

MASER 10 MHz

VLBI MASER SYMMETRICOM SIGMA TAU

PO

P

CO

MP

UT

ER

DA

M

CO

MP

UT

ER

P3

P4

VM

E C

HA

SS

IS

1

RISLEY PRISM MVP

CONTROLLERS

2

MET4 WEATHER

DEVICE

RS

23

2

STARTDIODE

SLR START DIODEMonsanto MD2 Fiber Optic

Transcievers (Typical)

10 MHz

7

Drawing Notes:

Please refer to drawing D-08 for a listing of all

notes and callouts on this drawing.

9

9

8

TO THE EVENT TIMER

TO THE TIMING

BOX

TO THE ICC

TO THE GPS

TIME AND FREQ.

RECIEVER

TO POP ON THE

VME CHASSIS

TO THE ICC8

10

11

68 PIN SCSI II CABLE

11

3

5

4

12

12

1 PPS

COMPARATOR INPUT DATA(SCSI)

COMPARATOR INPUT DATA(IDC)

COMPARATORTEST PULSE

OUT

CH9 CH10 CH11 CH12

OUTPUT DATA

J1

J10

CH5

J6

CH1

J2

J11

CH6

J7

J12

CH7

J8

NIM INPUT DATA

CH2

J3

CH3

J4

J13

CH8

J9

J16

CH4

J5

10 MHZ IN

J17

J15

J14

EVENT TIMER

OSCILLOSCOPE

FIBER OPTIC CABLE

6

* Uses coaxial cable

Located at VLBI

1414

Located at NGSLR

WINDMILL

ANEMOMETER

TO CONNECTOR ON BACK OF RACK (SEE NOTE C, DRAWING R-02 FOR DETAILS)

CR-02

ZFDC-20-3A

IN

CPL

INVERTINGTRANSFORMER

LHRS LOCAL

CONTROLLER

Mount Controller

EM ERGEN CY

STOP

OFF

ON

POW ERSHUTTER

EM ISSIO N

NORTHROP GRUMMAN

OFF ON

Photonics Industries

POW ER

Connector # Function

P1 Commands & Status (To / From POP)

P2 LRO Laser Beam Block

P3 2 kHz Laser Beam Block

P4 MCP Shutter

P5 Star Camera Shutter

P6 Remote Beam Block Control Box (Enable/Disable)

P7 LRO Laser ND Insert

P8 2KHz Laser ND Insert P9 Remote Control Box

P10 MCP ND Insert

P11 Cable Integrity

P12, P13 Spares

28

Hz

MC

P W

ind

ow

Window / Window

Co

mm

an

d a

nd

Sta

tus

Command and Status

Window / Window

2 kHz

LRO Laser Tr igger

SLR Laser TriggerMCP Gate

5 MHz 1 PPS1 PPS

IN OUT

1 PPS

12 V DC Power

Supply

DOME

CONTROLLER

STARTDIODE

LRO START DIODEMonsanto MD2

INVERTINGTRANSFORMER 1 2 3

1. Aircraft Detect2. 20 degree Elevation Switch3. Radar Command (Slave/Manual)

Co

mm

an

d a

nd

Sta

tus

MOBLAS 7 TRAILER

IO Chassis "P Series" Connections

Remote Beam Block

Control Box (Enable/

Disable)

Remote

Enable Box

14 14

1 PPS DISTRIBUTION

TO THE

LHRS 16

16

PIB

TO PIB

15

GA

TE

4 C

HA

NN

EL

S

GA

TE

CO

MM

ON

A Module B Module C Module D Module

T Z W

DELAY

OU

T

T Z W

DELAY

OU

T

T Z W

DELAY

OU

T

T Z W

DELAY

OU

T

LRO START

LRO START

SLR START

Test Point

J1J1P2

P5

P8

P11

P3

P6

P9

P12

P4

P7

P10

P13

J9

J17

J21

J2

J10

J18

J22

J3

J11

J19

J23

J4

J12

J20

J24

J5

J13

J6

J14

J7

J15

J8

J16

J25 P1

MOBLAS-7 FIRE

MOBLAS-7 1 PPS

LHRS HVAC

CONTROLLER

HUMIDITY

LHRS FIRE

IOC Interface

NETWORK SWITCH

CAMERA

COMPUTER

RAT DICOM

NETWORK

SWITCH

X X

X

X

X X

Ethernet

Ethernet

X

X

X

X X

KeyDamaged, unit not

working correctly

Damaged port, but

unit still functional

Outside system

Outside system

VIASALA

INSTRUMENT

Damaged outside unit

MOBLAS 7

DIS

CR

IMIN

AT

OR

LHRS

RADOME

TEMPERATURE

17

17

LHRS

RADOME

TEMPERATURE

Telephone

System #1

Telephone

System #2

STALAS

TELEPHONE

CONNECTION

NGSLR System Damage