# Optical problem concerning space mirror.

• fatjohn
In summary, the conversation discusses the use of a mirror to reflect extra light to a photovoltaic ground station on earth for a space-based energy satellite. The main difficulty with this option is that the different angles of light from the sun's poles would result in a 336 kilometer wide circle of illumination on Earth. The group discusses potential solutions, including using lenses or metamaterials, but the constraint of a restricted mirror-image distance presents a challenge in creating a smaller image of the sun on the ground.

#### fatjohn

When designing a space based energy satellite for our project, we ran across the option to just use a mirror to reflect extra light to a photovoltaic ground station on earth. The main difficulty of this option is that due to the fact that the light coming from the south pole of the sun hits the mirror with a different angle then the light coming from the north pole a 336 kilometer wide circle on Earth would be illuminated.
Is there any way to overcome this problem either with a configuration of lenses or with certain metamaterials or nanomaterials? It seems to me that at a certain (focal) point on the mirror light hits it in a various different angles. This is a problem that to my knowledge cannot be overcome with macro devices. Anybody has a proposition?

fatjohn said:
Is there any way to overcome this problem either with a configuration of lenses or with certain metamaterials or nanomaterials?
Or you could just use a concave mirror
You are trying to make an image of the sun on the ground

mgb_phys said:
Or you could just use a concave mirror
You are trying to make an image of the sun on the ground

Yes I am trying to make an image of the sun on the ground but i am trying to make that image as small as possible. A concave mirror cannot do the job this is because at one point of the mirror the light comes in at a variaty of angles.

That is true of any lens or mirror making an image of a finite object.

You have an extra constraint that the mirror-image distance (and so focal length) is restricted which sets the minimum size of the image.

## 1. What is an optical problem concerning space mirror?

An optical problem concerning space mirror refers to any issue or challenge that arises when using a mirror in space for scientific or technological purposes. This could include issues with reflectivity, distortion, or damage to the mirror.

## 2. Why are mirrors used in space?

Mirrors are often used in space to help focus and direct light or other electromagnetic radiation. They can also be used for communication, navigation, and remote sensing purposes.

## 3. How is the problem of distortion in space mirrors addressed?

Distortion in space mirrors can be addressed through careful design and construction, as well as regular maintenance and calibration. Advanced technologies such as adaptive optics can also help correct for distortion in real-time.

## 4. Can space mirrors be repaired or replaced?

Yes, space mirrors can be repaired or replaced, but it is a complex and costly process. Astronauts may be able to repair minor damage during a spacewalk, but for larger repairs or replacements, a specialized spacecraft or robotic mission may be needed.

## 5. Are there any new developments in space mirror technology?

Yes, there are ongoing developments in space mirror technology, including the use of lighter and more durable materials, as well as advancements in adaptive optics and other techniques to improve the performance of space mirrors.