Space

Big beach balls: this is what new space telescopes will look like

If we ever have giant inflatablestelescopes in space, you can say thank you to mom Chris Walker. A few years ago, Walker was making chocolate pudding, when suddenly he had to interrupt his culinary business and call his mother. He removed the pudding from the stove, covered it with plastic wrap and set the pot on the floor near the couch. After the conversation, he was surprised to find an image of a bulb from a lamp nearby, hovering over the end of the couch. Investigating the cause of this phenomenon, he found that the pocket of cold air, which was formed during the cooling of the pudding, led to sagging of plastic packaging to pudding. In fact, it formed a lens that reflected a light bulb.

Inflatable telescope: how it works

"I thought: it's cool, but there is no use, ”says Walker, a professor of astronomy at the University of Arizona. But 30 years later, he found application as a basis for the proposal, which was sent to NASA Innovative Advanced Concepts, a program to finance a variety of aerospace ideas.

The essence of the proposal was to turngiant inflatable beach ball in a space telescope. Such a suborbital aerostat reflector would not interfere with interference, like ground-based telescopes. In addition, it could be easily scaled, thereby opening up the vast expanses of the universe for observation without a fair price tag associated with the construction of large and durable telescopes.

The idea of ​​creating a large air reflectoremerged as a result of Walker's work on the Stratospheric Terahertz Observatory (Stratospheric Terahertz Observatory), a one-meter telescope attached to a high-altitude balloon that flew in the upper atmosphere over Antarctica for several weeks. Walker watched as the balloon was inflated with 15 million cubic meters of helium, and it occurred to him that there was a lot of empty space for such small telescopes in a balloon. It would be nice to use the balloon itself as an observatory. This observation, combined with the memory of that pudding incident decades ago, led to the creation of the first inflatable telescope.

In 2014, Walker and his students madeThe first prototype of a large inflatable reflector from a large inflatable plastic sphere sold by a Chinese toy manufacturer. This ball was designed for people to climb inside, but it found application in radio astronomy. Walker hung the antenna inside the ball and sprayed inside the metallic paint to create a reflective surface. This primitive installation allowed Walker and his students to conduct radio observations of the sun from the roof of an astronomical building at the University of Arizona. And although it was not sent to the upper atmosphere, it was obvious that even a very simple version of the telescope could give good results.

How do inflatable telescopes work?

Walker realized that the real benefits ofspherical inflatable telescope will manifest in space. Traditional radio telescopes use parabolic plates as reflectors that collect radiation and focus it on a specific point. Although this, in principle, works, astronomers must move the entire plate so that it points to a specific place, and this is inconvenient when the telescope is in space. Thanks to Walker's design, it is possible to direct the telescope by moving the antenna inside the sphere, without moving the whole telescope. The spherical telescope also has a wide field of view, so it can visualize large portions of the universe without movement.

Walker's inflatable telescope - not the firsta case where NASA is showing interest in beach balls in space. In the early 1960s, NASA launched Echo 1 and Echo 2, which were massive reflectors that could passively reflect radio signals throughout the world. But no one has ever used this concept to observe far space. Proving that his large ball reflector works, Walker received a grant to develop the space version of an inflatable telescope.

So Terahertz Space Telescope was born - inflatableThe ball is 40 meters in diameter with a controlled antenna inside. Since gas pressure in space is very low, Walker says that it would be possible to inflate a massive telescope using less gas — nitrogen or neon, due to the low freezing temperatures — than is required to inflate the ball on Earth. Obviously, space junk and micrometeoroids are a problem for inflatable objects in orbit, but Walker says that the slow diffusion of gas in a telescope means that it will be blown away in years.

The diameter of the telescope will be about 25 meters. For comparison: the lens of the James Webb space telescope, which is scheduled to launch in 2021, is 6.5 meters in diameter. The difference in price is even more significant: Walker expects that $ 200 million will be required to launch his telescope, while James Webb will cost $ 10 billion by the time it was launched.

It remains only to build it. If everything works out, Terahertz Space Telescope will be able to observe the Universe using wavelengths that allow it to detect the presence of water in deep space. This means that we can find asteroids with a high water content in our solar system or even water in the habitable zones of other solar systems.

Well, we will follow the results of Walker. In the meantime, subscribe to our channel, so as not to miss.