How Transistors Facilitated the Space-Age and How Far They’re Going to Take Us

In 1947, William Shockley, John Bardeen, and Walter Brattain changed the future of newly emerging electronics [1]. They successfully demonstrated transistor amplification using a point contact transistor, which brought about a computing revolution [2, 3]. This led to the large first-generation vacuum tube computers that would often take up entire rooms, and that are now compressed into the hand-held devices we all own today. Transforming the analog age of vacuum tube processing systems such as the ENIAC (Electronic Numerical Integrator and Computer), the transistor was the key catalyst of the digital age [4]. The ENIAC was the first programmable, general-purpose computer operated by six women; it was built during World War II and occupied a room 15 m by 9 m, and had over 6,000 switches. It was the most powerful, and yet most complex, electronic system at the time [5, 6]. Transistor technology allowed the creation of small, lightweight computers that would fit onboard spacecraft (Fig. 1). Transistors continue to inspire technological advances across all sectors of engineering. However, their contribution to both the space and the healthcare industry offers the chance to transform many more lives [7]. By enabling a digital revolution, transistors have brought into reality technology previously thought of as science fiction. They have successfully transformed our lives and provided us with an opportunity to contribute to the advancement of the UN Sustainable Development Goals, furthering our knowledge of both the world we live in and ourselves.

Figure 1 - Transistors and Space. By Amber Briscoe, Youth STEM Matters Artist.

What Are Transistors?

In essence, a transistor (Fig. 2) is a small semiconductor device with two main functions: to amplify current and act as a switch in electrical circuits. Usually made out of silicon, a semiconductor has a conductivity value between a good electrical conductor and an effective insulator. This property allows them to change resistivity under certain temperatures, making them perfect for controlling the flow of electricity in a circuit [8].

Figure 2 - A range of transistors  Credit: Ben Merghart [9].

Transistors and Space 

Launched in 1957, Prosteyshiy Sputnik 2 was the first spacecraft that included transistors, as well as a living animal: a dog named Laika [10]. Despite the overheating malfunction that caused the death of Laika and the limited use of transistors in only a few instruments, the mission was the first to successfully prove that transistors could be used above the Earth’s atmosphere. Eventually, in January 1958, the satellite Explorer 1 was launched, marking the beginning of satellites that used only transistors in their equipment [11, 12]. 

The primary instrument on Explorer 1 was a cosmic ray detector invented by James Van Allen: it was this instrument that made the first discovery of the Space Age - the existence of Earth’s radiation belts [13]. The Van Allen Radiation Belt is a zone of energetically charged particles, held in place by the Earth’s magnetic field. It is composed of an inner belt (1,000 km to 12,000 km above the Earth) and an outer belt (13,000 km to 60,000 km above the Earth), sheltering us from high-energy particles and deadly solar winds that could cause irreparable destruction to the atmosphere [14, 15, 16]. These zones represent the start of Space Age discoveries, and their detection has allowed satellite technology to be built to be more resistant to these conditions. As space systems get smaller, the importance of particle interference increases, leading researchers to design spacecraft that are able to withstand these hazardous conditions [17]. Transistors enabled the era of space discovery, and revolutionised our understanding of the universe beyond our atmosphere. 

With 2,666¹ operational satellites now orbiting the Earth, Explorer 1 was the beginning of a growing reliance on remote sensing and satellite communication systems [18]. Satellite data is helping to contribute to our understanding of the Sustainable Development Goal 13: Climate Action, and has enabled us to alter our behaviours to slowly combat the growing climate emergency [19]. In addition, throughout the COVID-19 pandemic NASA, the European Space Agency (ESA) and the Japanese Aerospace Exploration Agency (JAXA) have used satellite data to create the COVID-19 Earth Observation Dashboard — a platform that monitors the global impact of the pandemic on the agriculture, economic and climate sectors [20]. The transistor enabled the first satellite carrying scientific equipment to enter Earth’s orbit, and its legacy continues across all sectors integral to our lives.

Innovation and the use of transistors still continues. A newly emerging field of self-healing transistors pioneered by the Korean Advanced Institute of Science and Technology (KAIST) may provide a solution to deep space exploration [21]. Using nanowire transistors to withstand cosmic rays and high levels of radiation, these small-scale spacecraft hope to reach our nearest star, Alpha Centauri, in under 20 years [21]. Despite the many challenges involved, this new method of space exploration may eventually allow us to explore further from Earth than ever done before [22].

Now a global centre of cutting edge technology, Silicon Valley’s reputation is partially due to the privatisation of transistor production. In 1955, William Shockley created the ‘Shockley Semiconductor Laboratories’ [23]. After disputes over his leadership qualities, a group known as the ‘Traitorous Eight’ defected from Shockley to establish their own company - ‘Fairchild Semiconductors’ [24]. Working closely with MIT, Fairchild Semiconductors produced the integrated circuits for the Apollo missions. The company built itself a reputation for reliability and innovation [25]. Eventually, in 1968, Robert Noyce and Gordon Moore resigned from Fairchild to start ‘Intel' - altering the future of the microprocessing system [26].

The incredible transformative nature of transistors is not only confined to the space industry, as transistors become smaller in line with Moore's law². They also are becoming more efficient and inexpensive, and hence, more accessible to a larger audience.

Transistors and Healthcare 

In recent years the use of transistors in health care has become a rapidly expanding field. Furthering the progress of the Sustainable Development Goal 3: Good Health and Well-Being, the transistor is continuing its positive contribution to our way of life. Researchers at Tufts University have developed completely flexible transistors from linen thread [27]. These transistors can then be attached to clothing, placed directly on the skin, or integrated as biomedical sensors inside the body. By monitoring real-time human biomarkers, the potential to improve the resolution and accuracy is immense. One such application is the detection of radiation in cancer treatment [28].

According to Cancer Research UK, nearly 50% of cancer patients receive some type of radiotherapy [29]. Utilising the sensitivity of transistors, an increase in dose accuracy could be established, reducing the side effects of damaging healthy cells. A radiation detector based on an organic transistor that uses an electric field to control the flow of current would be able to act as a dosimeter relaying real time radiation exposure information [30, 31]. Not only would this enhance the effectiveness of the treatment but it would also aid patient care and wellbeing . Using organic semiconductor materials in transistors provides a simple yet effective and cost‐efficient solution for the early detection of disease [32]. By taking the electrical properties of semiconductors and the inexpensive manufacturing processes used to make organic materials³, these transistors could assist in daily disease prevention, guaranteeing greater quality of life.

Conclusion 

The transistor revolutionised our lives and continues to do so. It has helped us reach the moon and communicate across oceans. It may even take us further from Earth than we have ever gone before. However, its use is expanding beyond that of classic electronic devices. Flexible, high functioning transistors are the beginning of a new era of accessible personalised health care and, like their use in the Space Race, transistors are the catalyst for the modernisation and transformation of the healthcare industry. They are playing an important role in advancing the Sustainable Development Goals and have become an integral part of our everyday lives.

Footnotes

1. Data is correct as of April 2020.

2. In 1965, Gordon E. Moore predicted that the number of transistors on a microchip doubles every two years thus increasing the speed and capacity of the computer. Currently, the rate at which this occurs is much quicker then every two years [33].

3. Organic materials can be processed from their liquid state using processes such as mould injection and even 3D printing.

References

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