Writing and Research - Week of 03/02/2015

The Fourth Week

During my fourth week, I mainly worked on a report that detailed the variables and the application I was considering for my final product: my origami rover. In this blog post, I’ve included a few details from that report:

The Application

Rockets that take human-made devices to space such as the Space Shuttle or the Delta II rocket tend to have very limited space in their fuselage or payload fairing. Figure 3 shows how the fuselages of the Space Shuttle are either extremely small or has a very small width in comparison to its length. As a result, a collapsible rover would be extremely advantageous when fitting the device onto a rocket’s fuselage or payload fairing. When discussing rocketry, space (in terms of volume) is extremely valuable, and through using a rover that takes advantage of the Miura fold, a larger rover could be fitted into the fuselage/payload fairing.

Figure 3: A diagram of the Space Shuttle. Notice the size of the aft fuselage and the width of the mid fuselage.

Variables to Consider for the Folding Material

There are many variables to consider when choosing the material that will be folded into the Miura fold:

1. Ductility: The definition of high ductility is the ability for a material to change shape under tension without breaking. This is important to the Miura fold because many metals will break if folded and unfolded many times along a single crease due to its brittleness (low ductility). As a result, materials with low ductility is not ideal for this fold. In addition, folding metals seem to lower the ductility of that metal along that crease.
2. Malleability: Malleability is the general ability of a metal to change shape under compression. This property allows for a metal to be made into a sheet and be folded. However, a high malleability also seems to make a metal hold its folded form without change, which is not desired for the Miura fold. A Miura fold should be able to easily transition between its collapsed and decompressed states.
3. “Ability to hold a crease”: If a material is able to maintain a crease impressed on it, then origami could probably be applied to that material, and the material will probably have a memory of how it was folded. Robert Lang has used this idea to apply origami from materials ranging from cloths to metals.
4. Stiffness: Stiffness in this context is defined as “the measure of force required to bend a material through a specific angle.” If the stiffness of a material becomes too high, the advantages of folding the material into the Miura fold disappears due to the inability to alter the state of the Miura fold easily.
5. Curl: The curl of a material is defined as  “the systematic deviation of a sheet from a flat form.” One reason why a material may experience curl is due to internal stresses inside the material as a result of folding. This specific type of curl is called “Structural curl.” Ideally, the curl of the material should be low so that the stresses within the material does not cause the material to curl up when it is in the compressed state of the Miura fold.

Brief Discussion of the Size of the Rover

Rovers and space probes tend to be fairly large when dealing with space exploration in order to fit several instruments aboard the devices. For example, the Philae spacecraft for the Rosetta mission was nearly a cubic meter! However, rovers and space probes dedicated to a single instrument can be significantly smaller and have more power available to that single instrument. As a result, this project will focus on a rover smaller than the traditional rover.

That concludes my fourth week! I will try to catch up on posts by next week. Until then!

-Parthib Samadder

Further Reading

• http://www.materialconnexion.com/Home/Matter/MatterMagazine81/PastIssues/MATTER61/CreaseandFold/tabid/691/Default.aspx
• http://www.paperonweb.com/paperpro.htm
• http://history.nasa.gov/diagrams/e3-5.htm
• http://www.langorigami.com/paper/paper.php