Starshade - From Japan to space

Can you recall the sweet memories of childhood when we used to float paper boats on rainwater? Can you remember the excitement of throwing paper rockets to see which one moves the farthest? Do you believe the techniques we used to turn paper into a rocket are being used in mainstream projects all around the world?

With the big commotion out there for colonizing Mars, space exploration also getting high attention not only from organizations like NASA but also from astronomy enthusiasts and local communities. One of the main targets of space exploration is to discover new exoplanets which are highly likely to sustain life.

But the problem is these exoplanets are extremely dim when compared with their host stars and they are located very close to the host stars making it more difficult to observe. Currently, the method used by satellite telescopes to capture them is known as the transit method. Even though the transit method is widely used, this is not very effective.

When we want to observe a bird around noon, we usually cover the Sun with our hands to see it clearly, right? In a bright environment, if we can block the direct light emitted from the light sources, other objects become more detailed and easier to observe. Starshade is a proposed spacecraft that can utilize the above method to create an artificial eclipse effect, so the exoplanets will be exposed to the telescopes.

The star shade is an enormous sunflower-like structure that can shield the telescope from the direct light of the host star. This structure is supposed to be 36m in diameter. A structure of this size is too huge to be transported in a rocket. If you are wondering what is the connection between a small paper boat and a giant sun shield, here is the big secret. Both of them are applications of origami. Since the structure is as large as a baseball ground the scientists and engineers of the Jet Propulsion Laboratory (JPL) of NASA are using techniques of origami to compact the massive shield to fit in a modern rocket.

The Starshade model has two major parts. The middle part of the sunflower is like a shield. It can be folded into a small hexagonal-shaped object. The outer petals are rolled over it. Although the design looks simple, these parts should be unfolded in the space at millimetre accuracy. The biggest challenge for JPL scientists is to implement the theoretical model on a large scale with higher precision. They have already built smaller versions of the model and currently enlarging it to the required size. The project has been under discussion since 2005 and yet it was not been able to implement successfully. But there are signs that this will be realistic within the next few years.

Starshade is not the first spacecraft that uses origami techniques. ‘Mars phoenix lander’ had a fan-folded solar array named ‘Ultraflex’. It was a solar array wing with Z folding pattern. Miura folding pattern, which is a very famous technique to fold a thin surface layer into a small area of space has used in the ‘SPROUT’ satellite and the space flyer unit in 1995. Apart from space technologies origami is extensively used in designing airbags, stents for heart patients, foldable gadgets etc.

Although origami is mostly observed as a compacting method in most science applications, there are various aspects of this ancient art that are yet to be discovered. One such great potential can be found in structural engineering. By implementing origami techniques, it is possible to produce higher quality, strong structures with unique aesthetic appeal. There are research being conducted exploring new dimensions of applications. But the practical implementations are still comparatively very low. Origami can be sighted as one of the major fields to which engineers should pay more attention in near future.

Origami is the art of paper folding which is one of the stunning ways of expressing oneself creatively. Even though we often use the term origami for all folding practices irrespective of the origin, these techniques are believed to be emerged and developed in ancient Japan. One time it was just a method used for home decorations. Now origami has become the major building block of a giant space project. From Japan to space it has evolved and will emerge as a cutting-edge technology in future.

References

1.  Starshade Would Take Formation Flying to Extremes

https://www.jpl.nasa.gov/news/starshade-would-take-formation-flying-to-extremes

2. Science within the art of origami

https://assamtribune.com/science-within-the-art-of-origami/

3. Incredible Technology: Giant Starshade Could Help Find an Alien Earth

https://www.space.com/25172-starshade-alien-earth-exoplanets-incredible-tech.html

4. Space Origami: Make Your Own Starshade

https://www.jpl.nasa.gov/edu/learn/project/space-origami-make-your-own-starshade/

Thilanka Pathum Weerasekara
Third year,
Department of Electrical & Electronic Engineering, Faculty of Engineering, 
University of Peradeniya.