orblogoOrbital Sciences Corporation

Principal software engineer for several satellites. Responsible for software system design and development; subsystem interface design; command and telemetry definitions; ground station to spacecraft interface definition; software coding standards; reliability and multi-satellite configuration issues; command & telemetry definitions; fault detection and correction software; and hardware interface drivers.

OrbcommOrbcomm Satellite

Orbcomm is Orbital Sciences global communications satellite network consisting of 28 low earth orbiting (LEO) satellites.  The system is used to send and receive two-way alphanumeric packets, similar to two-way paging or e-mail with global coverage.

My responsibilities:

  • Principal software engineer on the satellite software development team.  Responsibilities included software system design, subsystem and common (cross subsystem) software development.
  • System Design
    • Overall software system design
    • Developed spreadsheet database to define ground station to spacecraft and inter-subsystem command and telemetry interfaces.  Database also is used to manage data specific to individual satellites (orbit parameters, calibration parameters, etc.).
      • C include files, with command and telemetry tables, are automatically generated for both the ground station and the satellites to enforce these interfaces, help prevent human error and increase reliability.
      • Developed preliminary Access database to replace Excel spreadsheets.
    • Software coding standards.
    • Configuration management.
    • Reliability and multi-satellite configuration issues.
    • Command & telemetry definitions.
  • Subsystem Development
    • Developed the satellite's gateway (ground station interface subsystem) software.
  • Common Code Development (code resident on several subsystems).
    • System level and subsystem level fault detection and correction software (Health and Maintenance).
    • Digital Signal Processor (DSP) driver (dsp communications, telemetry, code loading, memory washing)
    • SCP (Serial Communications Port) bus driver for communication with 3-wire serial devices (plls, adcs, dacs, etc)
    • Table (spreadsheet) driven command handling, and utility routines.
  • Satellite Specifics
    • VxWorks operating system - WindRiver's Orbcomm page
    • 68302 processor
    • C/assembly language


APEX (Advanced Photovoltaic and Electronics Experiment) was Oribital's first satellite and an Air Force experimental satellite to test advanced electronic components in the space environment.   - JPL Mission and Spacecraft Library:APEX, Gunter's Space Page:APEX

My responsibilities:

  • Lead software engineer responsible for the software system design, development and integration.
  • System Design
    • Software system design
    • Ground support equipment definition
    • Command and telemetry format definitions
    • Subsystem interface definitions
  • Subsystem Development
    • Spacecraft Control Module (SCM subsystem)
      • Frame Formatter
      • Command Sequencer
      • File Backhauler
    • Payload Services Module (PSM subsystem)
      • Payload Interrogators (DOS, PP, CRUX, FERRO)
  • Common Code Development (code resident on both subsystems)
    • System level and subsystem level fault detection and correction software (Health and Maintenance).
    • 68302 communications drivers (HDLC, SCLC, ascii, OX.25)
  • Satellite Specifics
    • OSX operating system (a custom version of the Precise MQX operating system)
    • 68302 processor
    • C and assembly language
  • Acted as technical assistant to the Air Force supporting on-orbit operations.

X-34X-34 Hypersonic Rocetplane

X-34 - An air-launched, hypersonic rocketplane being developed by Orbital for NASA's Reusable Launch Vehicle (RLV) program.

  • Real-time simulation development
    • Simulation of LN100 inertial navigation subsystem.
    • Simulations of other X-34 subsystems.
    • DOS drivers to configure, transmit and receive messages thru multi-channel serial communication boards (digi board, 202, others).

BATSAT / T1Batsat (Teledesic's T1 Satellite

Teledesic's T1 Satellite - The world's first commercial 'Ka' frequency band LEO spacecraft (previously called the Broadband Advanced Technology satellite (BATSAT)).

SeastarSeastar Satellite

Seastar - Orbital's second PegaStar satellite, now called OrbView-2 carries the Sea Viewing Wide Field-of-View Sensor (SeaWiFS) and provides high-fidelity color images of the Earth.

  • VRTX operating system
  • Modifications and debugging of Global Positioning System (GPS) driver.
  • Modifications and debugging of OX.25 (an internal messaging protocol) driver.
  • Matrix math library optomization
  • Compiler/floating point math library debugging (Linking, NAN problems)