This article details the creation of a custom star tracker for astronaut Don Pettit to capture stunning images of star trails and other celestial phenomena from the International Space Station (ISS). Engineer Jas Williams collaborated with Pettit to design a barn-door tracker that could withstand the ISS's unique environment and operate with Pettit's existing camera equipment. Key challenges included compensating for the ISS's rapid orbit, mitigating vibrations, and ensuring the device was safe and functional in zero gravity. The resulting tracker employed stepper motors, custom-machined parts, and open-source Arduino code, enabling Pettit to take breathtaking long-exposure photographs of the Earth and cosmos.
This PetaPixel article details the fascinating process of designing and building a custom star tracker for astronaut Don Pettit, enabling him to capture stunning astrophotography images from the unique vantage point of the International Space Station (ISS). The project originated from Pettit's desire to create breathtaking images of star trails, showcasing the Earth's rotation against the backdrop of the cosmos. Conventional star trackers, designed for terrestrial use, were unsuitable for the ISS environment due to factors like vibrations from the station's systems and the rapid orbital speed, which presents a different set of tracking challenges compared to Earth-based astrophotography.
Driven by this need, a collaborative effort involving Pettit, engineer Jaspal Chadha, and a team at the Johnson Space Center commenced. They embarked on designing a specialized star tracker dubbed the "Barn Door Tracker," referencing its resemblance to a traditional barn door. This ingenious device employs two plates connected by a hinge, with one plate fixed to the ISS and the other housing the camera. A carefully calibrated screw mechanism allows for precise adjustment of the angle between the plates, enabling the tracker to compensate for the ISS's orbital motion and keep the camera locked onto the stars.
The design process was iterative and involved meticulous calculations to determine the required tracking rate and the optimal screw pitch for the hinge mechanism. The team also had to consider the constraints of the ISS environment, including limited resources and the need for a compact and easily operable device. Furthermore, the tracker had to be robust enough to withstand the vibrations and temperature fluctuations experienced on the ISS.
The Barn Door Tracker's construction involved utilizing readily available materials and components, further highlighting the ingenuity of the project. Testing and refinement were conducted on Earth, simulating the conditions of the ISS to ensure its effectiveness. Once finalized, the tracker was transported to the ISS, where Pettit put it to use, capturing mesmerizing star trail images that showcased the beauty of the cosmos from an unparalleled perspective. The article highlights the unique challenges and innovative solutions involved in creating a specialized piece of equipment for space-based astrophotography, showcasing the intersection of scientific ingenuity and artistic pursuit in the extreme environment of the ISS. The successful deployment and operation of the Barn Door Tracker not only facilitated Pettit's artistic endeavors but also demonstrated the potential for adaptable and resourcefully designed tools in space exploration.
Summary of Comments ( 3 )
https://news.ycombinator.com/item?id=42701645
Hacker News users generally expressed admiration for Don Pettit's ingenuity and "hacker" spirit, highlighting his ability to create a functional star tracker with limited resources while aboard the ISS. Several commenters appreciated the detailed explanation of the design process and the challenges overcome, such as dealing with vibration and thermal variations. Some discussed the technical aspects, including the choice of sensors and the use of stepper motors. A few pointed out the irony of needing a custom-built star tracker on a space station supposedly packed with sophisticated equipment, reflecting on the limitations sometimes imposed by bureaucracy and pre-planned missions. Others reminisced about previous "MacGyver" moments in space exploration.
The Hacker News post "Designing a Star Tracker for Astronaut Don Pettit to Use on the ISS" has generated several comments, discussing various aspects of the project and Don Pettit's ingenuity.
Several commenters praise Don Pettit's resourcefulness and "hacker" spirit, highlighting his ability to create tools and conduct experiments with limited resources in the unique environment of the ISS. They appreciate his commitment to scientific exploration and his willingness to improvise solutions. One commenter specifically refers to Pettit as a "MacGyver in space," encapsulating this sentiment.
A thread discusses the challenges of astrophotography from the ISS, focusing on the difficulties posed by the station's movement and vibration. Commenters explore the technical intricacies of compensating for these factors, including the importance of precise tracking and stabilization. The original design of the "barn door tracker" and its limitations are also discussed, along with the advancements achieved with the newer, electronically controlled tracker.
Another commenter notes the interesting detail about using parts from a Russian cosmonaut's treadmill for the barn door tracker, further illustrating the improvisational nature of work on the ISS. This anecdote sparks a brief discussion about the collaborative environment on the station, where astronauts and cosmonauts from different nations work together and share resources.
Some comments delve into the technical specifics of the star tracker, discussing the choice of motors, control systems, and the challenges of operating equipment in the harsh conditions of space. The use of off-the-shelf components versus custom-designed parts is also touched upon.
Finally, a few commenters express their admiration for the ingenuity and dedication of the individuals involved in designing and building the star tracker, acknowledging the complexities of creating a device that can function reliably in such a demanding environment. They also appreciate the opportunity to learn about the behind-the-scenes challenges and solutions involved in space exploration.