Podcast Summary: T-Minus Space Daily – "Astrophotography and the ISS with Don Pettit"

Release Date: December 21, 2024

Introduction to Astrophotography on the ISS

In this episode of T-Minus Space Daily, hosted by Maria Varmazes from N2K Networks, the spotlight is on the intriguing world of astrophotography aboard the International Space Station (ISS). The episode features an insightful interview with NASA astronaut Don Pettit, a seasoned chemical engineer renowned for his orbital astrophotography and in-space inventions. Launched to the ISS on September 11, 2024, aboard the Roscosmos Soyuz MS.26 spacecraft, Don Pettit serves as a flight engineer on Expedition 72, where he dedicates approximately six months to conducting scientific experiments and maintaining the space station.

Importance and Challenges of ISS Photography

Don Pettit delves into the significance of capturing images from space, emphasizing how these photographs serve as tangible memories and stories that bridge the gap between life on Earth and the extraterrestrial experience of living aboard the ISS.

Don Pettit [02:55]: "Images from space help tell the story to people on Earth that don't have the opportunity to go into space when your mission is over. It's photographs and memories... the photographs help complete the story of what it means for human beings to expand into space and expand into this frontier."

The challenges of astrophotography in microgravity are also discussed. Pettit highlights both the obstacles and advantages that come with photographing from an orbiting laboratory, such as managing reflections through the station's multiple window panes and utilizing the weightlessness to maneuver heavy camera equipment effortlessly.

Capturing Starlink Satellites

One of the standout topics in the conversation is Pettit's experience capturing images of Starlink satellites. Initially appearing unexpectedly in his imagery, Pettit decided to document these satellites intentionally once they became a recurring feature in his photographs.

Don Pettit [03:55]: "The images that I've sent down that show the Starlink satellites are ones that I intentionally did. Those bright reflections are only seen in an orbital environment from another orbit. Those reflections do not get down to Earth."

This discovery underscores the unique perspective astronauts have, observing phenomena that are not visible from the ground, thereby enriching the scientific and visual narrative of space activities.

Perspective from Space on Earth Events

Pettit articulates how observing Earth from the ISS provides a vastly different perspective compared to viewing events on the ground or even from an airplane. With an event horizon of about 4,000 kilometers, the continuous and expansive viewpoint allows for a more comprehensive understanding of planetary events.

Don Pettit [04:51]: "When you get on space station, our event horizon, our field of view is about 4,000 kilometers. So it really changes the perspective of what you see. You see the same thing, but it gives you a different perspective."

This broadened perspective enables a deeper appreciation and analysis of Earth-based phenomena, potentially influencing how such events are interpreted and addressed on a global scale.

Advancements in Photography Equipment on the ISS

The interview touches upon the recent upgrades to the ISS's photography toolkit, including new cameras, lenses, and ND filters. Pettit explains how these advancements enhance the quality and capabilities of space-based imaging.

Don Pettit [05:56]: "The newer technology is exactly that. It's newer technology and it allows us to operate and take the imagery in a manner that the older cameras would not allow."

He highlights a specific lens, a 15mm wide-angle with an F-stop of 1.5, which permits more light to be captured, thereby enabling the collection of previously unattainable imagery.

Influence of Microgravity on Photography Operations

Microgravity plays a pivotal role in how photography equipment is handled aboard the ISS. Pettit demonstrates with an 800mm telephoto lens and a solar filter, showcasing the ease of maneuvering heavy equipment without the constraints of gravity.

Don Pettit [07:04]: "Here you could have it on a little arm and because it is weightless, you don't need to worry about schlocking it around. You could just push it around with two fingers and do imagery in a way that you can't do on Earth with this camera and this lens system."

This flexibility allows for innovative shooting techniques that are impractical on Earth, expanding the creative possibilities for space-based photography.

Considerations for Shooting Through the Cupola Windows

Photographing through the ISS's cupola windows presents unique challenges due to the complex window structure designed to withstand micrometeorite impacts and maintain atmospheric pressure. Pettit describes the window assembly, which includes multiple panes, each contributing to potential reflections that must be managed during photography.

Don Pettit [08:22]: "Each one giving a bit of a reflection. And you're always trying to fight reflections off the windows in a way that you typically don't need to worry about on Earth."

Understanding and mitigating these reflections is crucial for achieving clear and unobstructed images of space.

Custom Tracking Devices Developed for Astrophotography

A significant highlight of the conversation is Pettit's development of a home-built tracking device known as the Orbital Sidereal Drive. This device compensates for the ISS's rapid rotation, allowing stars to remain pinpointed in long-exposure photographs—a feat not possible without such innovation.

Don Pettit [09:52]: "This device rotates once every 90 minutes. So it counteracts the rotation, attitude motion of station. And now it allows you to photograph stars as pinpoints. You could do time exposures."

The creation of both mechanical and battery-operated versions ensures redundancy and reliability, reflecting NASA's standard for mission-critical equipment.

Handling Photography Workflows and Sharing Data

Managing the vast amount of imagery captured aboard the ISS requires efficient workflows. Pettit relies on ground-based support teams from the Astronaut Office and the Photo TV group to handle image processing and distribution, allowing him to focus on data collection.

Don Pettit [15:50]: "I rely on these people heavily because I want to spend my time on space station collecting the primary data, the imagery."

This collaborative approach ensures that the high-quality images Pettit captures are effectively shared with the public and scientific communities without burdening him with post-processing tasks during the mission.

Balancing Scheduled Work and Personal Photography

While the ISS mission is meticulously planned, Pettit emphasizes that personal astrophotography is conducted during off-duty time. The structured schedule prioritizes scientific research and station maintenance, with photography serving as a personal passion project that enriches the overall mission experience.

Don Pettit [17:44]: "Most of our work is actually that we have a timeline... we take pictures during these operation tasks... but it's a labor of love and that's what astronauts spend a lot of their off duty time doing."

This balance ensures that essential mission objectives are met while still fostering personal endeavors that contribute to the broader narrative of space exploration.

Capturing Starship's Sixth Flight from the ISS

A notable achievement discussed is Pettit's successful documentation of SpaceX's Starship sixth flight from the ISS. This endeavor required precise timing and coordination, leveraging the ISS's orbital mechanics to capture the launch.

Don Pettit [19:17]: "We happened to be within sight of Boca Chica during the launch... it was just the way the clockwork of orbital mechanics and the schedule for launching worked out."

Assisted by fellow astronaut Suni Williams, Pettit was able to orient his equipment effectively, resulting in a series of high-quality photographs showcasing the Starship launch from an unprecedented vantage point.

Most Unexpected or Personally Significant Images

Among the myriad of images captured, Pettit highlights two particularly significant sets. The first involves photographing freezing thin wafers of ice to study crystal structures under polarized light, utilizing a specialized freezer onboard that reaches temperatures of minus 100 degrees Celsius.

Don Pettit [20:37]: "I did some imagery of freezing thin wafers of ice so that you could look at the interlocking single ice crystals under polarized light."

The second notable project is his ongoing work with the Orbital Sidereal Drive to achieve starfield images previously unattainable, marking a personal and technical milestone in space-based astrophotography.

Conclusion

The episode concludes with heartfelt appreciation for Don Pettit's dedication to astrophotography aboard the ISS. His efforts not only enhance scientific understanding but also bring the awe-inspiring beauty of space closer to those of us on Earth.

Don Pettit [21:27]: "Because when you make images like that, it really helps bring home space flight to people."

The interview underscores the symbiotic relationship between advanced technology, personal passion, and collaborative support in advancing space exploration and public engagement.

Produced by Alice Carruth, Associate Producer Liz Stokes, Mixed by Elliot Peltzman and Trey Hester, with Original Music by Elliot Peltzman. Executive Producer Jennifer Ibin and Executive Editor Brandon Karp oversee the production, under the leadership of President Sivone Petrella and Publisher Peter Kilby.

For more insights and updates, visit N2K Networks.