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I n t e g r a t e d D e s i g n C e n t e r / M I s s I o n D e s I g n L a b o r a t o r y

N A S A G O D D A R D S P A C E F L I G H T C E N T E R

Do not distribute this information without permission

from Gerry
Daelemans

(gerard.j.daelemans@nasa.gov)


X
-
Ray Calorimeter Mission

Flight Software

David
Leucht


02


06 April, 2012


Flight Software,
p
2

Final
Version

M i s s i o n D e s i g n L a b o r a t o r y

Do not distribute this information without permission

from Gerry
Daelemans

(gerard.j.daelemans@nasa.gov)


02
-
06 April, 2012

X
-
Ray Calorimeter


Spacecraft flight software for a dual redundant system


Command and data handling


3
-
axis stabilized stellar pointing attitude control system


Payload support including mechanisms control and heath & safety monitoring


Power system control and battery management


COMM management including HGA pointing



Development approach consistent with NPR 7150.2. Reuse of
LRO/GPM flight software based on the Code 582 Core Flight
Software System (CFS)



Three
testbeds

for flight
sw
/hw I/Fs, FSW build/system tests



Flight software sustaining engineering



Flight
hardware/software based on proven in
-
house or COTS
system, no
creditable technical
risk identified
(i.e
., no show
-
stoppers
)





Overview






Flight Software,
p
3

Final
Version

M i s s i o n D e s i g n L a b o r a t o r y

Do not distribute this information without permission

from Gerry
Daelemans

(gerard.j.daelemans@nasa.gov)


02
-
06 April, 2012

X
-
Ray Calorimeter

Flight SW Architecture

New

Inter
-
task Message Router (SW Bus)

Event

Services

EDAC

Memory

Scrubber

Stored

Commanding

Software

Scheduler

Housekeeping

Manager

Executive

Services

Time

Services

File

Manager

Transceiver

Commands

Core Flight Executive (
cFE
) Heritage

Flying on LRO

Core Flight System (CFS)
Heritage

Deployed for I&T on GPM and MMS

Memory

Dwell

Real
-
time Telemetry

Comm Cards

Local

Storage

Power

Control

File downlink

Software

Bus

Payload

Manager

Command

Ingest

Telemetry

Output

Checksum

Memory

Manager

HK Data

Storage

Mass

Storage

System

Table

Services

Attitude

Determination

&

Control

Limit

Checker

1553

Control

Orbit

Models

Re
-
engineered

From LRO/GPM

Memory

Scrub

CFDP

HGA

Pointing

FSW development will use ASIST T&C GSE (to
maximize reuse of heritage FSW test product)

Mechanism

Control

Flight Software,
p
4

Final
Version

M i s s i o n D e s i g n L a b o r a t o r y

Do not distribute this information without permission

from Gerry
Daelemans

(gerard.j.daelemans@nasa.gov)


02
-
06 April, 2012

X
-
Ray Calorimeter


Class B full redundancy, fail safe mission, cold backup avionics


Broad
-
Reach Engineering BRE440 C&DH avionics


Diagnostic S/W and SUROM will be COTS from Broad
-
Reach


Payload perform science data collection, compression, CCSDS
packetization

and time stamping


C&DH/FSW provides commands and accept housekeeping data from payload
via 1553


Science data will be directly relayed to onboard SSR via RS422


Command decryption is done by hardware


Passive thermal control


GNC FSW development will use modeling and
autocode

generation method


Safe
-
hold (Sun avoidance for payload, power positive & thermally safe) will be
manually developed by an independent team


No controlled Re
-
entry


FSW development will use ASIST T&C GSE (to maximize reuse of heritage
FSW test product)


Assumptions

Flight Software,
p
5

Final
Version

M i s s i o n D e s i g n L a b o r a t o r y

Do not distribute this information without permission

from Gerry
Daelemans

(gerard.j.daelemans@nasa.gov)


02
-
06 April, 2012

X
-
Ray Calorimeter


FSW Product Development Process Shall Comply with NPR 7150.2A, NASA
-
STD
-
8719.13B and GSFC GOLD Rules. Class B for all mission critical FSW


Uplink/downlink management including Communication Security Box
management. FSW shall be capable of supporting following COMM rates
to/from DSN:


S
-
band 2 kbps command, 8 kbps HK telemetry


Ka
-
band 20 Mbps science data, payload telemetry, and S/C telemetry


Command and data handling, comply with CCSDS


Time management and distribution, 100 microsecond accuracy with periodic
updates from ground


3
-
axis stabilized attitude control system


CSS(8), ST(2), SIRU (1), RW(4), Thrusters(12)


Up to 10 Hz sensors data acquisition and processing; 10 Hz control cycle


Up to 10 Hz
Kalman

filter


ACS control modes: Acquisition; Cruise/Sun
-
point; Science (i.e. slew, calibration, inertial
hold); Thruster


Ground initiated momentum management using thrusters (i.e. delta H)


Ground initiated L2 insertion/orbit adjust using thrusters (i.e. delta V)


Perform sun avoidance (not even slew by, Moon is ok) for payload’s mirror(s) and
detector(s)


Dual axis HGA pointing


2 Hz Safe
-
hold Controller software using CSS, IRU, RW


Onboard ephemeris propagator with periodic ground updates




FSW Requirements (1 of 3)

Flight Software,
p
6

Final
Version

M i s s i o n D e s i g n L a b o r a t o r y

Do not distribute this information without permission

from Gerry
Daelemans

(gerard.j.daelemans@nasa.gov)


02
-
06 April, 2012

X
-
Ray Calorimeter


Payload support


Provide time synch, 100 microsecond accuracy


1553/RS422 I/F


Payload commands pass through


Payload science/HK collection (instruments to put science/HK and time data in CCSDS packets)


Collect and forward ACS ancillary data (i.e. telescope alignment monitoring data, ACS attitude,
etc.)


Heath and Safety monitoring



Mechanisms Control


Solar array deployment (hardware initiated with software backup)


Inner Purge Shield deployment (once time command)



Recorder Memory Management, store and forward HK and science data using
CCSDS File Delivery Protocol (CFDP) and including downlink rate margins


123
Gbits

for 72 hours nominal data plus 12 hours of peak data


258
Gbits

for 72 hours
worst
casel

data plus 12 hours of peak data



S/C Power System Electronic Support


Switched Services and Battery Management


FSW Requirements (2 of 3)

Flight Software,
p
7

Final
Version

M i s s i o n D e s i g n L a b o r a t o r y

Do not distribute this information without permission

from Gerry
Daelemans

(gerard.j.daelemans@nasa.gov)


02
-
06 April, 2012

X
-
Ray Calorimeter

FSW Requirements (3 of 3)


Onboard autonomy


Absolute & relative time
-
tagged command sequences


Limit checker


Health & Safety Management


Memory Checksum Management


EDAC Memory Scrub Management


Parameter Table & Memory Management


Serviceable: allow FSW updates, patches and/or entire module (capabilities to
start, stop, delete module without shutting down the system)


Provides three spacecraft simulators


one for each payload development teams
and one spare


Flight Software,
p
8

Final
Version

M i s s i o n D e s i g n L a b o r a t o r y

Do not distribute this information without permission

from Gerry
Daelemans

(gerard.j.daelemans@nasa.gov)


02
-
06 April, 2012

X
-
Ray Calorimeter

Processor Utilization Estimates

IAU

~60% margin

Flight Software,
p
9

Final
Version

M i s s i o n D e s i g n L a b o r a t o r y

Do not distribute this information without permission

from Gerry
Daelemans

(gerard.j.daelemans@nasa.gov)


02
-
06 April, 2012

X
-
Ray Calorimeter

Source Line of Code (SLOC)
Estimates

Flight Software,
p
10

Final
Version

M i s s i o n D e s i g n L a b o r a t o r y

Do not distribute this information without permission

from Gerry
Daelemans

(gerard.j.daelemans@nasa.gov)


02
-
06 April, 2012

X
-
Ray Calorimeter

C&DH/PSE FSW
Testbed

Instruments

Sim

IAU

BB

GDS with

GNC models

ASIST

System

FEDS

Development

Workstation

1553

1553

Analysis
Tools

Bus
Monitor

Serial Line

Ethernet

1 PPS


Top
-
Level Requirements:


Support C&DH FSW development


Support C&DH FSW build integration


Support C&DH FSW build test


GDS to checkout GNC I/Fs

Detector
ElectronicsBB

Decryption
Sim

FSW development will use ASIST T&C GSE (to
maximize reuse of heritage FSW test product)

RIU BB

PSE BB

Flight Software,
p
11

Final
Version

M i s s i o n D e s i g n L a b o r a t o r y

Do not distribute this information without permission

from Gerry
Daelemans

(gerard.j.daelemans@nasa.gov)


02
-
06 April, 2012

X
-
Ray Calorimeter

ACS FSW
Testbed


Top
-
Level Requirements:


Support GNC FSW development


Support GNC FSW build integration


Support GNC FSW build test


FSW development will use ASIST T&C GSE (to
maximize reuse of heritage FSW test product)

Instruments

Sim

IAU

BB

Full up GDS
with

GNC
models

Flight Dynamics

ASIST

System

FEDS

Development

Workstation

1553

1553

Analysis
Tools

Bus
Monitor

Serial Line

Ethernet

1 PPS

Decryption
Sim

Flight Software,
p
12

Final
Version

M i s s i o n D e s i g n L a b o r a t o r y

Do not distribute this information without permission

from Gerry
Daelemans

(gerard.j.daelemans@nasa.gov)


02
-
06 April, 2012

X
-
Ray Calorimeter

FSW System/Maintenance
Testbed


Top
-
Level Requirements:


Support FSW system test


Support mission operation training


Support FSW maintenance


FSW development will use ASIST T&C GSE (to
maximize reuse of heritage FSW test product)

Instruments

Sim

IAU/
Safehold

ETU

Full up GDS
with

GNC
models

Flight Dynamics

ASIST

System

FEDS

Development

Workstation

1553

1553

Analysis
Tools

Bus
Monitor

Serial Line

Ethernet

1 PPS

Detector
Electronics ETU

Decryption
Sim

RIU ETU

PSE

ETU

IAU

ETU

Flight Software,
p
13

Final
Version

M i s s i o n D e s i g n L a b o r a t o r y

Do not distribute this information without permission

from Gerry
Daelemans

(gerard.j.daelemans@nasa.gov)


02
-
06 April, 2012

X
-
Ray Calorimeter

Elements Required For FSW Development

(Inc. Deliverables/Receivables)

PROVIDER

ITEM

Flight


S/C Simulator (3)


Flight Software Builds

Ground System


ASIST GSE (3)


Front
-
End Simulator (3)

C&DH


IAU BB (2)


IAU ETU set (1)


RIU BB and Detector Electronics BB set (1)


RIU ETU and Detector Electronics ETU set (1)

ACS



ACS Dynamic Simulator (3)

Power


PSE BB (1)


PSE ETU (1)


Instrument Developers




Instruments Simulator (3)

Lackland

AFB


Decryption Box Simulators (3)

Flight Software,
p
14

Final
Version

M i s s i o n D e s i g n L a b o r a t o r y

Do not distribute this information without permission

from Gerry
Daelemans

(gerard.j.daelemans@nasa.gov)


02
-
06 April, 2012

X
-
Ray Calorimeter



Recommend add feedback/position sensors to all mechanisms
to facilitate onboard autonomous fault detections and
corrections



Further study might be needed to ensure primary CDH fault
(CBE ~30 seconds to power up the cold backup CDH and regain
control of the spacecraft) does not risk putting the Sun on/near
the
boresight

of the telescope






Recommendations

Flight Software,
p
15

Final
Version

M i s s i o n D e s i g n L a b o r a t o r y

Do not distribute this information without permission

from Gerry
Daelemans

(gerard.j.daelemans@nasa.gov)


02
-
06 April, 2012

X
-
Ray Calorimeter

Acronym list


ACS

Attitude Control Syste
m


ASIST

Advanced Spacecraft Integration and


Test System


BB

Breadboard


C&DH

Command and Data Handling


CCSDS

Consultative Committee for Space Data


Standards


cFDP

CCSDS File Delivery Protocol


cFE

Core Flight (S/W) Executive


CFS

Core Flight (S/W) System


COTS

Commercial Off the Shelf


CSS

Coarse Sun Sensor


DSS

Digital Sun Sensor


EDAC

Error Detection and Correction (circuitry)


ETU

Engineering Test Unit


FSW

Flight Software


FSS

Fine Sun Sensor


GNC

Guidance, Navigation and Control


GDS

GSFC Dynamics Simulator


GSE

Ground Support (test) Equipment




HGA

High Gain Antenna


HK

Housekeeping


MW

Momentum Wheel


ROM

Read
-
Only Memory


RW

Reaction Wheel


RWA

Reaction Wheel Assembly


SA

Solar Array


SIRU

Space
Inertial Reference unit


SSR

Solid State Recorder


ST

Star Tracker


SUROM

Start
-
up ROM (boot program)


T&C

Telemetry and Command



Flight Software,
p
16

Final
Version

M i s s i o n D e s i g n L a b o r a t o r y

Do not distribute this information without permission

from Gerry
Daelemans

(gerard.j.daelemans@nasa.gov)


02
-
06 April, 2012

X
-
Ray Calorimeter

Backup Slides


System Diagrams from Avionics


Layered Software Architecture and Heritage


Development Approach


Management Approach


Verification & Validation


Flight Software Maintenance

Flight Software,
p
17

Final
Version

M i s s i o n D e s i g n L a b o r a t o r y

Do not distribute this information without permission

from Gerry
Daelemans

(gerard.j.daelemans@nasa.gov)


02
-
06 April, 2012

X
-
Ray Calorimeter

Avionics System Diagram

(from Avionics team)

Flight Software,
p
18

Final
Version

M i s s i o n D e s i g n L a b o r a t o r y

Do not distribute this information without permission

from Gerry
Daelemans

(gerard.j.daelemans@nasa.gov)


02
-
06 April, 2012

X
-
Ray Calorimeter

Analog Acquisition

cPCI

RS422

1553

AXSIO
Physical

(Hardware) Layer

OS Services Layer

(
VxWorks

OS,

582 OS Abstraction Layer)

System Support Layer

(582’s Core Flight Exec)

AXSIO

Application Layer


Med/High Heritage For
Common Functions (e.g.,
Stored Commanding, Health &
Safety, Command
Management),


Low/No Heritage For Mission
Unique Functions (e.g.,
Deployables
, Payload, ACS,
power)


Processor

BRE440

Non
-
Volatile

Memory

Volatile

Memory

VxWorks

OS

Bootstrap

Loader

HK

Driver

Memory R/W

Driver

Software Bus

Exec & Task

Services

Time

Management

Event

Handler

Telemetry

Management

SSR Management

Stored

Commanding

Command

Management

Health & Safety

Subsystem Telemetry Monitoring,

Checking and Response

Payload Support

C

Table

Management

Power

Deployables

Safe Hold

ACS

Thermal

Housekeeping

COMM

Digital I/O

Timer

Driver

PCI

Driver

COMM

Driver


I/O

Driver

RS422

1553

Driver

Timers

Comm.

Processor Layered Software

Architecture & Associated Heritage

Flight Software,
p
19

Final
Version

M i s s i o n D e s i g n L a b o r a t o r y

Do not distribute this information without permission

from Gerry
Daelemans

(gerard.j.daelemans@nasa.gov)


02
-
06 April, 2012

X
-
Ray Calorimeter


Reuse LRO/GPM C&DH FSW (Med to high heritage, low risk
-

LRO
launched 2009)


LRO FSW Features (based on 582’s Core Flight Executive)


Being developed using FSW best practices consistent w/NPR 7150.2


Onboard file systems and associated file transfer mechanisms


Onboard networks with standard interfaces


Standard application interfaces (API) for ease of development and rapid
prototyping


Dynamic application loading, middleware (SB) provide dynamic cmd/tlm
registration


POSIX APIs and open source Integrated Development Environment


Benefits


Will enable parallel collaborative development and system interoperability


Will automate many previously manual development activities


Will simplify technology infusion and system evolution during development and
on
-
orbit


Will enable
rapid deployment of low cost, high quality mission software



New development for all mission specific components


ACS, Instrument support, mission
-
specific ops concept support, power
electronics, etc.

FSW Development Approach

Flight Software,
p
20

Final
Version

M i s s i o n D e s i g n L a b o r a t o r y

Do not distribute this information without permission

from Gerry
Daelemans

(gerard.j.daelemans@nasa.gov)


02
-
06 April, 2012

X
-
Ray Calorimeter


Product Development Process Will Comply with NPR 7150.2 (NASA
Software Engineering Requirements, now a GOLD Rule)


Development


Product Development Plan per 582 branch standards, approve by Branch &
Project


Detailed FSW development schedule integrated with project & subsystems
schedules


Requirements management using MKS tool


Monthly PSR with AETD & project; branch status reviews


Weekly system engineering meetings, FSW team meetings


FSW Design & Code reviews


Major milestones (SCR, PDR, CDR, etc)


Configuration Management


FSW CM Plan per 582 branch standards, approve by Branch & Project


Commercial CM tool (i.e., MKS) to manage source codes and document


Proposed FSW changes affecting missions requirements, cost and/or schedule
will be forwarded to Project level CCB


Test Plan


FSW Test Plan per 582 branch standards, approve by Branch & Project



Management Approach

Flight Software,
p
21

Final
Version

M i s s i o n D e s i g n L a b o r a t o r y

Do not distribute this information without permission

from Gerry
Daelemans

(gerard.j.daelemans@nasa.gov)


02
-
06 April, 2012

X
-
Ray Calorimeter

FSW Verification and Validation


Unit Test


Done by developers using PC tools


Follow Branch 582 Unit Level Test Standard
-

Tailored


Includes Path testing,
Input/Output

testing, Boundary testing, and Error Reporting
verification


Occasionally BB H/W is required to verify H/W I/F


Build Integration Test


Done by developers to verify that the FSW performs properly on the BB H/W in the
FSW
testbeds

using embedded system tools


First level functionality ensured for integrated software


Build Test Team to assist in GSE I/F checkout


Build Verification Test


Done by independent test team with GNC Analyst support on the BB H/W in the
FSW
testbeds

using embedded system tools


Test each requirement in the Flight Software Requirements documents (where
possible at the build level)


Use test scenarios to test requirements in both a positive and negative fashion.


Scenarios constructed to combine requirements that are logically connected to
create a test flow.


Automation to be utilized as much as possible


Requirements Traceability Matrix maintained



Flight Software,
p
22

Final
Version

M i s s i o n D e s i g n L a b o r a t o r y

Do not distribute this information without permission

from Gerry
Daelemans

(gerard.j.daelemans@nasa.gov)


02
-
06 April, 2012

X
-
Ray Calorimeter

FSW Verification & Validation (cont)


System Test


Done by independent test team including Flight S/W Maintenance & Flight
Operation Team members with support from GNC analyst, AXSIO system
& subsystems


Top
-
down approach with end
-
to
-
end testing


Test scenarios will focus on the operational aspects of the flight software.
For each test, as much as practical, all software will be running, including
all C&DH, ACS and PSE applications with checks and responses enabled


Stress test of the FSW will demonstrate correct performance at peak CPU
and bus loading


Perform negative testing from an operational perspective, system level
failure modes test & analysis


Flight qualify Ground System Telemetry & Command Database


Test scenarios can be used to support S/C CPT


Tests will be Performed on System/FSW Maintenance
Testbed


Flight Software,
p
23

Final
Version

M i s s i o n D e s i g n L a b o r a t o r y

Do not distribute this information without permission

from Gerry
Daelemans

(gerard.j.daelemans@nasa.gov)


02
-
06 April, 2012

X
-
Ray Calorimeter

Flight Software Maintenance


Code 582 will provide FSW Maintenance for X
-
Ray Calorimeter


Dedicated FSW Maintenance Team will be responsible for maintaining
the FSW


Maintenance staff will be a part of the FSW Acceptance Test Team


FSW Maintenance development will be performed in the System/FSW
Maintenance Test Bed