Protein Crystallisation Diagnostic Facility
A Multi-user facility for the investigation of the nucleation and crystallisation of biological macro-molecules
The Protein Crystallisation Diagnostics Facility (PCDF) is a multi-user instrument for the fundamental study of the processes of nucleation and crystallisation of biological macro-molecules, and specifically, how these processes are influenced by gravity.
This instrument can conduct detailed measurements of physical phenomena in individual reactors, and control these phenomena through changes in temperature and concentration of solution. The facility resides in the European Drawer Rack multi-user facility.
Operation and utilisation
Accommodation & Transport
The electronics unit is housed in an International Sub-rack Standard drawer, and was launched integrated within the European Drawer Rack facility. The European Drawer Rack was launched inside the Columbus laboratory.
The processing unit was accommodated within the Shuttle's middeck locker, and was launched fitted with its initial set of four reactors (either batch or dialysis type). The advantage of this approach was that several of the Space Shuttle middeck accommodation slots could provide power to the locker during transportation to and from the International Space Station - the processing unit requires power during the ascent and descent phases.
Operational Concept
The Protein Crystallisation Diagnostics Facility consists of a processing unit and an electronics unit. The processing unit contains a process chamber into which experiment boxes containing reactors are placed.
The experiment boxes also include drive systems for individual injection of solutions into the reactors, and a stirrer to agitate solutions. Diagnostics are provided within the process chamber, or may be installed directly within the experiment boxes. The electronics unit accommodates all of the controls necessary for the performing the experiments.
The possible modes of operation of the instrument are:
- Automatic - using pre-programmed sequences, controlled by the built-in electronics;
- Remote - using telecommands from the ground;
- Local - operated by a crewmember, either via the portable computer and/or via the command interface on the front panel.
The processing unit remains on-orbit for a complete mission increment, after which time it was returned to the ground in a Space Shuttle. The electronics unit remained on the International Space Station for over two years.
When on the ground, the experiment boxes within the processing unit may be exchanged for a new set. Following removal of the crystals in a temperature-controlled ground laboratory, the reactors are emptied, cleaned, and re-filled with a fresh solution in readiness for the next flight campaign.
Data and digital video images are either stored on the International Space Station, or transmitted to the ground control station, depending on the transmission capabilities at the time of the experiment. Video images (including microscope images and interferogrammes) can be stored in the host facility (e.g. the European Drawer Rack) video subsystem. When a suitable communication link is available, this data may be transmitted to the ground, and forwarded to the investigators.
Utilisation scenario
The utilisation scenario for the Protein Crystallisation Diagnostics Facility is based on that of the European Drawer Rack - the host facility. This operations scenario relies upon a high degree of cooperation between the supporting ground facilities. These include the Facility Responsible Centre that is in overall charge of the facility, together with the User Home Bases, from which each customer will support their own individual experiments.
The master timeline is derived from the European Drawer Rack operations plan as defined by the Facility Responsible Centre together with the involved User Home Bases. The main objective of the operations plan is to match the required resources with those available from the Columbus Laboratory to maximise the number of experiments that can operate simultaneously.
Schedule
The Protein Crystallisation Diagnostics Facility is run in the European Drawer Rack that was launched into space inside the European Columbus laboratory in February 2008.