Titanium box to help scientists conduct experiments in space Thursday, 19 October 2017

Humans have come a long way in space travel since Buzz Aldrin and Neil Armstrong stepped onto the moon in 1969, with Richard Branson saying commercial flights to space could be just six months off.

But as humanity has continued to explore space, the challenge hasn’t just been on getting there, but in also coming back and what bacteria people might bring back with them.

Inventor Raviteja Duggineni, a master’s student in aerospace engineering at the University of Adelaide, is hoping to help stop the spread of diseases from space by developing a 3D-printed titanium box that tests can be conducted in while the box is in space.

Due to the high cost of conducting tests in space of more than $1 million, he wanted to use existing technologies to bring down the cost to less than $100,000.

Duggineni has been working on a prototype of the box for about six months, and hopes that researchers and scientists can more easily could conduct their research in space due to the lower cost and simplicity of his product.

The titanium box measures 10 cm x 10 cm and has been designed to be integrated into a CubeSat – a class of research spacecraft developed to facilitate access to space for education and space exploration.

Each cube is 10 cm x 10 cm x 10 cm, with NASA Ames launching its first CubeSat in December 2006.

The development process for Duggineni’s box has involved three aspects: structural, biological, and electronics and communication.

The box needed to be made from a lightweight material with a high strength-to-weight ratio. It also needed to have thermal resistivity and low thermal diffusivity, have radiation insulation and also be modular and scalable.

To deal with the weight, Duggineni used titanium due its light weight and ability to handle several types of loads such as shock, vibration, tension and compression.

Titanium was also available for metal 3D printing at the Australian National Fabrication Facilities at the University of Adelaide.

Duggineni also developed a single arm/side design instead of printing a whole four-sided box with organic mesh to give the cube high structural integrity and ensure it was modular and scalable for mass production.

While mesh such as hexagonal and square was considered for the box, organic mesh helped to decrease the weight and increase the structural integrity under vibrational loads.

Meanwhile, biological requirements included having 1 atm pressure, with temperatures in the range of 18–30 degrees Celsius, and experiment initialisation and bacterial growth needed to be controlled remotely.

“Maintaining a sealed environment with 101,325 Pa pressure difference across the box wall is challenging and complex, which makes it virtually impossible to produce a commercial-grade product at a low cost,” Duggineni said.

“For this reason, we adopted microfluidic chip technology to perform experiments on.”

This microfluidic chip has tiny spaces for the microbes to grow on and channels to insert or introduce biochemicals to perform experiments.

One of the most important challenges was the box needed to have enough volume to accommodate microbes and the necessary sensors to carry out tests and maintain an interior temperature of 20-36 degrees Celsius.

It also needed to deal with radiation temperatures on the surface of 600-800 degrees Celsius in sunshine and around -50 degrees Celsius in shadows and dark regions, and withstand exposure to different types of radiation such as ionised, cosmic and UV radiation.

Another challenge was the fact that CubeSat sits on a shelf for two to three months before launch and after space-validating tests. This meant trying to stop the growth of bacteria and finding out what the optimal temperature was to take the bacteria into space.

“Given its size and simplicity, it is complex to control or initiate bacterial growth at will. To overcome this challenge, we used temperature as an active method of controlling the growth of the bacteria in the microfluidic chip,” Duggineni said.

“The microfluidic chip is equipped with resistive heaters that can raise the temperature in each chamber to 30-45 degrees Celsius.”

Duggineni is currently carrying out work to control thermal conductivity and radiation penetration into the box, including applying ceramic and heat paints to insulate the heat transfer into the inner parts of the box.

He is also working on flow mechanisms – to initiate flow in the chambers, the team is using shape memory alloy in the chambers.

“Using this concept, we are working on a few designs to insert in the chambers so that it can initiate the flow,” Duggineni said.

Duggineni has already conducted tests with the box, including monitoring the growth of Streptooccus Pneummoniae and Staphylococcus aureus and the behaviour of antibiotics in space.

Duggineni expects it will take another two months to have a finished prototype, and four to five months to have a commercially available product that can be carried into space.