ivanishinIn the experiment, the "Great Start" continues the project "Space education. Russian astronauts explain and talk. "

The second story – the story of Anatoly Ivanishin about Russian high data rate X-Band system, 100 Mbps

Conducting scientific research and experiments is an important aspect of ISS operation. The results of experiments are data files. Scientists often need these data immediately after an experiment run has been completed, and therefore it is very important to promptly downlink these files for analysis. RF system for data transmission operates at 100 Mbps and enables prompt transmission of large amounts of data.

The system includes:

- high data rate X-Band system, 100 Mbps;

- antenna and feeder device;

- on-board data storage device.

Structurally, the high data rate system is integrated with the antenna-and-feeder device into a single high data rate system unit and is located on the outer surface of the Service Module between the second and the first planes.

There are two basic ways of feeding data into the onboard storage device. The first and the principal one is via RSS2 computer. The crew put the data files into a special directory, which is polled by the onboard data storage device control system. After each experiment we transfer the results on a flash card to this directory, and after that the data are automatically copied into the onboard storage device.

The data files can be too large to be downlinked in one session, therefore the onboard storage device has the capability to resume file transmission from the position where the transmission was interrupted by the ending of the communications session.

To protect the data against interference, the onboard storage device encodes it, breaks it up into small segments and sends it to the high data rate system, where the signal is modulated and amplified. The amplified signal is fed to the antenna-and-feeder device for downlinking.

The antenna – the transmission channel between the high-data-rate system and the ground station receiving the data – operates in single-frequency mode within the 8050 to 8400 MHz operating band (NASA concurrence with the rated value for the carrier frequency has been obtained). It polarizes the signal and assures the reception by the ground station. At present the station for receiving the signal from the high-data-rate system is located in Moscow, but in the course of time such stations will appear in other regions of Russia as well. The data from the ground station goes to MCC-M, where it is processed on a specialized computer in the experiments team. Based on the results of the processing a received flies acknowledgement file is generated, which, in automatic mode, is placed by the specialists of the Lead Operations Control Team (LOCT) into computer RSS2 via Regul-Packet link. This file is automatically copied into the onboard storage device and files that have been received on the ground are removed from the transmission queue in the device.

One more way of putting data into the onboard storage device is the payload block server.

This server receives data from scientific equipment operating in automatic mode. At present, one of such pieces of equipment is Foton-Gamma. In one day of operation it accumulates up to 50 MB of data. In the past cosmonauts used to return data on flash cards, but nowadays the data are promptly transmitted to Earth to the researchesrs in charge of the experiment.

In the center of the picture with an air duct for cooling down the device, which operates 24 hours a day

This broadcast was downlinked via the high data rate system. The video quality is perfect – compare it with videos posted on the web site earlier. Today we just can’t imagine how we could do without this data link. Once again, this data rate is not enough...C`est la vie! See you later.

Рассказ Анатолия Иванишина о р...
Рассказ Анатолия Иванишина о российской высокоскоростной системе передачи информации (100 Мбит/сек)





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