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The Inspector System consists of three elements:

The Space Vehicle itself and the Monitoring and Control Station, developed by Daimler-Benz Aerospace, Germany, and the Transport and Launch Container, developed by RSC ENERGIA, Russia.

Basically, the inspector space vehicle is a free- flying camera in space. However, to ensure that the camera focusses the right spot at the right time, a multitude of other subsystems are required for control of this complex operation. All in all, they can be compared to a photographer on Earth who controls zoom and focus, who aims at the target, takes the camera to the right place, and finally presses the release button. These tasks are accomplished for Inspector by:

2 thrusters (40 mN)
with fuel tanks
for position and attitude control
attitude control
system
with 3 gyro
wheels
star camera
video navigation
3 fibre optic gyros
for position and attitude determination
batteries
solar generator (cells)
for power supply
on-board computer as the "brains" to control all
processes onboard the
satellite

Inspector Expl

The Inspector space vehicle will be remotely controlled from the Monitoring and Control Station (MCS), which is installed in the core module of the Mir station.

The MCS is composed of a laptop PC, a video display, a video recorder and an electronic module for radio communications, power distribution and navigation. Cosmonaut-engineer Pavel Vinogradov will monitor and control the mission using the MCS. He will also control Inspector's camera by adjusting the focal length or changing the viewing direction by attitude maneouvres based on the video images.

After manual selection of so-called "target reference points", an automatic image processing algorithm calculates the relative position of Inspector with respect to Mir or Progress. Additionaly, the MCS offers the opportunity for on-orbit training, which is of particular importance due to the long time periods between initial ground training and mission execution.

The availability of ground contact is limited by the number of Russian ground stations and the particular orbit of Mir. Therefore the control of Inspector is performed by the crew, while the Russian flight control center ZUP near Moscow provides additional support using voice, data and video links. This causess also the limited availability of video signal transmissions.

INSPECTOR Mission

Inspector Mission

The Inspector demonstration mission will be performed within two days. On the first day Progress undocks from Mir and injects itself into a specific orbit w.r.t. Mir. It will stop at a distance between 600 and 800 m from the station.
One orbit (92.5 min) after Progress undocking , Inspector will be ejected the Transport and Launch Container (TLC) mounted inside the Progress docking adapter.
Direction and velocity during separation of Inspector will guarrantee a safe trajectory w.r.t. both Progress and Mir. Immediately after release, Inspector will fly around Progress to verify the full functionality of all systems.

On the second day - after the successful Progress mission - Inspector approaches MIR and performs several fly-arounds. Minimum distances to the station will be 100 - 150 m. The video system will provide for a resolution of up to 1 cm at that distance.

The major technical challenge for a small vehicle flying in the proximity of manned space stations is the safe operating mode. For Inspector this has been achieved flying on an "ellipse of safety", ensuring that a collision with Mir is avoided by the laws of physics. Therefore, in addition to the Mir video inspection task, the demonstration of this particular safety concept is major objective of the mission.

During assembly and operation of the future space station ISS (International Space Station) the performance of inspection, maintenance, and repair tasks will be required. The russian space station Mir, which is in use since 1986, is a good example for this need.

These necessary outboard activities are called EVA - Extra Vehicular Activity, a dangerous and time consuming task for the astronauts and an expensive one as well. Remotely controlled manipulator systems, robots featuring various capabilities, will support the astronauts in the future.

The "big robots", like the Canadien SSRMS (Space Station Remote Manipulator System) and the European ERA (European Robotics Arm) have only limited viewing and reaching capabilites. Free- flying satellites offer a high flexibility for all kinds of dexterous tasks and can complement larger systems. The first tasks envisaged to be performed by such small and autonomous systems are surveillance, observation and routine inspection.

As an example, a small, free - flying observer would have been very useful during inspection of the damage at the russian space station Mir, caused by a collision of a Progress vehicle in June 1997. Lacking this robotic support it took three months until an assessment could be done by egress of Mir crewmembers and inspection by the approaching Space Shuttle.


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Claudio Ariotti, IK1SLD



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