International Space Station  

The Wall Street Journal ran an interesting article this week which discussed a significant health issue affecting astronauts on the International Space Station (ISS). Despite its 25-year history and 279 visitors, astronauts frequently experience health problems like rashes, allergies, and infections. Surprisingly, researchers believe these issues stem from a lack of microbial diversity on the ISS.

The ISS environment lacks the diverse microbes found on Earth, particularly those from soil and water. This microbial imbalance may contribute to chronic inflammatory diseases in astronauts. Scientists suggest cultivating a more diverse microbial environment could improve astronaut health. A study led by Rob Knight from UC San Diego mapped the microbes on the ISS. The research found the ISS to be more sterile than Earth-based living spaces, with most bacteria being human-associated.

The lack of exposure to beneficial microbes from soil, animals, and plants may be affecting astronauts’ immune systems. Researchers are exploring ways to introduce beneficial microbes to space environments to support astronaut health. This research highlights the complex relationship between human health and environmental microbes, even in the context of space exploration. Maybe astronauts should bring their pets along with their microbes with them to the ISS.

The ISS is a testament to human ingenuity and international cooperation in space exploration. In this blog post I hope to provide a short history of the ISS and information about the ISS’s status and future. The orbiting laboratory has been continuously occupied for over two decades, serving as a platform for scientific research, technological innovation, and international collaboration.

The ISS’s journey began in November 1998, when the Russian-built Zarya module was launched into orbit. Two weeks later, in December 1998, the first U.S. component, called Unity Node 1, was added. The station’s assembly continued over the years, with modules and components delivered by various space agencies using both Russian rockets and the Space Shuttle.

A significant milestone was reached in November 2000, when the first long-term crew, Expedition 1, arrived at the station. Since then, the ISS has maintained a continuous human presence in space for over 24 years, hosting 279 individuals from 22 countries as of March 2024. The ISS news in 2025 was well covered in the news. Two astronauts who were delivered to the ISS by a Boeing spacecraft but, due to Boeing technical issues, their less than ten-day mission turned out to be nine months. They returned to Earth aboard a SpaceX Crew Dragon.

As of March 2025, the ISS remains a hub of scientific activity and international cooperation. The station orbits Earth at an average altitude of 250 miles, completing 15.5 orbits per day. It boasts a pressurized volume of approximately 35,000 cubic feet and a mass of about 450 tons.

The ISS continues to serve as a microgravity laboratory, hosting hundreds of scientific investigations across various disciplines. Its external instruments gather data on subjects ranging from astrophysics to climate change, while internal experiments cover fields such as microbiology and metallurgy. According to the latest information from NASA, more than 4,000 investigations have been conducted aboard the ISS over its 25-year history. The experiments have resulted in over 4,400 research publications, with 361 publications in 2024 alone. The research conducted on the ISS spans a wide range of scientific disciplines and has contributed to advancements in technology, medicine, and our understanding of space exploration.

The ISS has yielded numerous benefits across scientific, societal, and economic domains. Research conducted on the ISS has led to breakthroughs in areas like protein crystallization, which has implications for drug development. The station has driven advancements in life support systems, power generation, and communications technologies.

There are other benefits from the ISS. Part of the educational outreach is the station has inspired millions of students worldwide through direct communication with astronauts and educational programs. I have written about this before, specifically about amateur radio operators (hams). The ISS has had astronaut hams on board and they talked with student hams on Earth. I am a ham myself and this is on my list of things to do one of these days.

The ISS has fostered the growth of commercial space activities, including cargo and crew transportation services. This has created economic opportunities. Over $15 billion in total financing was attracted by startup space ventures. Ten space startups have gone public.

Although most experts consider the ISS to be a remarkable success, its operational life is nearing its end. NASA and its international partners have committed to operating the station through 2030. After that, the ISS will be deorbited and burn up in the atmosphere in a controlled manner to ensure safety.

There are several aspects to the ISS’s future. First is the deorbiting process: NASA has selected SpaceX to develop the U.S. Deorbit Vehicle (USDV), which will guide the ISS through its final descent in 2031. NASA is also looking at commercial successors and is supporting the development of commercial space stations to replace the ISS. NASA aims to ensure a seamless transition from the ISS to commercial platforms, maintaining a continuous human presence in low Earth orbit.

The ISS’s legacy will continue through the lessons learned, technologies developed, and international partnerships forged during its lifetime. Looking beyond the ISS, the future of space habitation appears bright, with multiple commercial and government-led projects on the horizon. The new platforms will build upon the ISS’s success, opening new opportunities for scientific research and space tourism.

In 2021, my son Aaron and I took a trip to the U.S. Space & Rocket Center in Huntsville, Alabama. They have mockups of two ISS modules containing 20 full-scale replica racks, as well as a full-scale replica of the Cupola Observation Module. I highly recommend visiting Huntsville. The visit provided the opportunity to experience the scale and complexity of the International Space Station through touring various full-sized models and replicas. You can also see the amazing Saturn V.

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