Does Russia have any concern this could be a tactical weapon and part of the missile defense shield or even a tactical weapon:
It would be a very inefficient weapon.
An easy target.
Early telescopes used shaped glass to bend light to magnify the image and make it appear closer. As the bits of glass got bigger however to make the image appear closer and closer it was found that there is a problem with bending light with glass.
Any glass prism will show that white light is made up of all the colours of the rainbow and when you shine light through glass the light tends to separate into its separate colours so images got colourful halos of bright colours.
The solution was to use a mirror so the light coming from a long way away comes into an open tube with no glass at the front to hit the bottom of the tube which is lined with a large flat mirror which both reflects and focuses the image back up to about half way up the tube to a small mirror that redirects the focused image sideways out of the tube to a small lens that can be used to adjust the focus to get a sharp clear image.
In big powerful telescopes replace the small mirror half way up the tube with an incredibly expensive CCD light sensor with a 100 mega pixel or better performance.
The sensor blocks some of the light so the mirror in the bottom of the telescope might have a bare centre, but to look at things as close as 100km away or as far away as distant galaxies you need to be able to very accurately flex the mirror to the correct focal length to properly focus the image. Because of the huge range of distances the CCD detector might move up and down the tube a bit as well, but the point is that the long tube in front of the mirror will make it very very difficult to catch sunlight and redirect it at something on the Earth... especially as the telescope itself will be zipping along at orbital speeds.
In this system however the mirrors are exposed and shielded from sunlight by a large shield.
The CCD sensor will be mounted somewhere on the craft and the mirrors will be angled to direct a view of the target into the sensor.
The system will be located near a Lagrange point to avoid entering the earths shadow... which is perfectly normal for a solar powered satellite
A Lagrange point is an area of zero real gravity.
In Earth orbit an object like the ISS is subject to Earths gravity... it keeps falling in a curve but because it is going so fast it misses landing on earth, or conversely it is trying to fly away from the earth but keeps falling back towards it enough so that its distance from earth never increases.
On board the ISS everything is "falling" at the same rate and appears to be weightless, but from an energy point of view every once in a while the engines need to be fired to maintain its orbital height.
To explain a Lagrange point it is a point of balanced or doubled or halved gravity. Think about the Earth and the moon.
Both have their own gravity though the Earths gravity is more powerful than the Moons gravity because the Earth has more mass.
If you were to move in a direct line from the Earth to the Moon for the first three quarters of the trip the Earths gravity would be the dominant force on you so if released or suddenly stopped in relation to both objects you would fall to Earth and not the the Moon.
As you get closer to the moon however the effect of the moons gravity will increase and the effect of the Earths gravity will diminish because gravity is directly related to the square of distance. Eventually you will reach a point where the earths gravity equals the moons gravity and they balance out. If you stopped there you would stay there and not fall towards either the moon or the Earth... the gravity of the Earth would stop you falling toward the Moon but the gravity of the Moon would stop you falling toward the Earth.
That is a Lagrange point.
Lagrange point 1 actually.
Lagrange point 2 for the Earth and the moon would be beyond the moon the distance where the gravity of the moon and the earth are equal again.
In this case L2 for the Sun and the Earth is shown on this diagram:
As anyone knows the closer to the sun the faster an object needs to go to prevent falling into that sun, so an object at the L2 position will be in about an 800,000km larger radius orbit than the Earth is... so if it wasn't an L2 point... if it was ahead or behind the Earth it would rapidly fall behind Earth. In the L2 point however it has the Sun and the Earths combined gravity to nudge it along and keep it in place so only a tiny amount of energy will be needed to keep it in place.
It is a bit like Cyclists using slipstreaming in a bike race to reduce the amount of energy they need to burn to hold position by getting in behind another cyclist. Of course this works because the cyclist in front is doing work pushing through the undisturbed air, which is work the cyclist behind does not have to expend energy doing. In space there is no air.
There is a stable Lagrange point between the Earth and the Sun though the passage of Venus and Mercury will upset an object at that point.
This satellite will orbit the L2 Lagrange point so it will fly in a circle around the L2 point. It is called a Halo orbit because from the ground looking directly up at the L2 point the satellites orbital path looks like a circle around that point.
At the L2 point the Earth would be constantly blocking some of the sunlight, but flying a halo orbit around L2 gives you all the gravity boost advantages of the L2 point plus the constant sunlight to the solar panels.
The sunshield also never needs adjusting because the telescope will always point away from the Sun (and Earth).
Personally I think if they really wanted a space based energy weapon they wouldn't put it on anything so public.
Equally space based energy weapons are overrated. A laser weapon will suffer about a 1mm divergence per metre of travel, so from 100km up the laser when it hits the ground will be 100m across... which is pointless for anything except ranging.
A over 1 million kms past Earths orbit this system (ie the CCD sensor and mirrors) would be damaged by exposure to the solar wind and the intense heat of direct sunlight.
To retain its shape the mirrors need to be kept at a constant temperature... shining sunlight on them would unevenly heat them leading to warped and useless mirrors till they were cooled down again or fully heated to an even max temperature. That even high temperature would probably melt or damage the mirrors which will normally be kept cryogenically cool to observe deep space objects.
It is designed to take light coming from millions of kms or trillions of light years and focus it on a point within the area of the spacecraft itself... it says it has a focal distance of 131m which means focusing on targets on Earth would be impossible anyway. At 800,000km away from the Earth and facing away from the Earth and the Sun there is zero chance this system could be used against anything on Earth or the Satellites in Earth orbit... even geostationary objects are much lower than this.