Satellites

Working for the European Aeronautic Defence and Space Company EADS Astrium at Immenstaad am Bodensee/Germany and Toulouse/France in 2009, my job description was to adapt existing procedures for testing satellite communication and hardware in the Assembly-Integration-Test phase before launch. The projects supported at the time were LISA Pathfinder, Earthcare, Sentinel-2, BepiColombo and Galileo. Each of these satellites introduced new requirements to the telecommand and telemetry database system and new challenges to the real-time software that monitors the hardware.

The satellites projects by EADS Astrium are not in the public domain, despite being substantially subsidized by the government. This page reports on the space related projects I was involved in before and after my time at the company.

Cansat - Remote Device to retrieve Atmospheric Data

Spacecraft Orbits

MissionControl

God knows what happens now.
Hopefully worldwide discussion, debates, and reforms...
I want people to see the truth...
because without information,
you cannot make informed decisions as a public.
Bradley Manning

MissionControl

Commands

The MissionControl software was developed for a nano-satellite project based in the Asia-Pacific region. I wrote the software in Java 7 during the period of Nov-Dec 2011.

Queue control

The software is intended for

• the testing of the nano-satellite before launch to support the development and validation of the on-board software and hardware
• the control of the nano-satellite during the entire mission in orbit

The MissionControl software performs the following tasks:

• auto-completion of the user defined commands: computation of parameters such as checksum, authentication codes, and execution timestamps
• sending of the commands via serial port to the uplink terminal node controller (TNC) for uplink by radio transmission
• reception of the telemetry by interfacing with a software library by Innovative Solutions In Space BV
• decoding of the telemetry according to data-types, physical units and conversion formulas
• logging of all communication events and data in raw-binary-, comma-separated-value-, and html-format
• autonomous processing of a predefined sequence of commands until a special event occurs (communication failure, negative acknowledgement, etc.) or the end of the sequence is reached.

The entry point to the MissionControl standalone application is the function main() in the class MissionControl. While MissionControl is running, the following configuration overview is shown at the top of the screen:

The field NOW displays the current time of the host computer. The host computer should be set to the Coordinated Universal Time zone (UTC). The timestamp in the field NOW is uplinked to the satellite for syncronization. The time is also relevant to derive parameters for the authentication of commands.

Exchange

The serial port needs to connect to the terminal node controller with baud 9600, no parity, 1 stop bit. During operation, the TNC needs to be in transparent mode. The elapsed time since the last uplink is displayed behind the serial port selector. The elapsed time is relevant while the satellite is in different states, as the on-board computer automatically exits the state after a certain period of no uplink.

Packet view

The downlink of the satellite enters the computer as an audio stream. The incoming packets of data are AX25-frames, which are decoded from the sound stream using a software library by Innovative Solutions In Space BV. The elapsed time display behind the frequency and volume information, is reset whenever frames are received as part of a requested packet.

The icons on the right enable the user

• to edit the command and parameter databases,
• to access to the recent log history,
• to display of available memory to the java virtual machine,
• to toggle the configuration overview window status to be 'always on top',
• to terminate the MissionControl application.

In the beginning the Universe was created.
This has made a lot of people angry
and is widely regarded as a bad move.
Douglas Noël Adams

MissionControl is a genuine product of Western Australia.