Astronomy for RVers – International Space Station


The world’s laboratory in the sky

By Chris Fellows, Serenity Mobile Observatory

The most expensive thing humans have ever built, the International Space Station whips around the globe 15.5 times a day or every 92 minutes; it has been continuously occupied for nearly 20 years; it’s about the size of a football field; and you can spot it with your naked eye if you know where and when to look.

ISS from the Space Shuttle Atlantis on 23 May 2010. Photo from NASA (Click to enlarge.)

With a price tag of more than $150,000,000,000 (I just had to write that out) and an average of 4 people on board since 2000, or about 30,000 people days, it costs just over 5 million dollars a day per crew member to live onboard the ISS. That is a pricey room even if it has a great view! Not all this money is being provided by your tax dollars, however. Five countries are part of a consortium that build, launch and service the space station and its missions. The United States, Russia, Japan, Canada, and the European Space Agency (ESA) all have dogs in this fight and have shouldered at least part of the bills.

The mission of ISS has evolved over its life from being a laboratory, observatory and factory in low Earth orbit and provide transportation and maintenance, and act as a staging base for possible future missions to the Moon, Mars and asteroids (these latter functions have yet to be realized). Ten years into its life, in the 2010 United States National Space Policy the ISS was given additional roles of serving commercial, diplomatic and educational purposes.

The ISS is very complex and has many modules that have been added on over the years. It currently has 32,898 cubic feet of pressurized space: for reference, that is about 1.5 times the volume of an average American home of 2,500 square feet with 8-foot-tall walls. As of June 5, 2011, 159 components had been assembled during more than 1,000 hours of Extra Vehicular Activity (EVA), or space walks. The total mass of the ISS is now near 1 million pounds.

The components of the ISS in an exploded diagram. Diagram from NASA (Click to enlarge.)

It would be too lengthy to describe all the modules here but I will provide a list of the major modules so you can look them up yourself – just follow the links provided; they all have interesting features and missions. The major modules of ISS are: Zarya, Unity, Zvezda, Destiny, Quest, Harmony, Tranquility, Columbus, Kibō, Cupola, Rassvet, Leonardo, Bigelow Expandable Activity Module, and International Docking Adapter-2. This of course doesn’t include all the truss segments, solar arrays, radiator panels, or the Canadarm2 robotic arm. All very cool and worth doing a little reading about.

You can see the ISS for yourself without any equipment or special skills. You just need to know when to look up. There are many websites and phone applications that will guide and alert you when ISS is overhead. I have selected a few here but you can do your own research and decide which you like the best. The website Heavens-above has many astronomical tools to play with including an ISS predicting tool that will tell you when and in which direction to look. For your phone you can try ISS Detector Satellite Tracker; there is also a pro version for a couple of bucks that adds features. Like I said, there are many more out there – poke around a little to find your favorite.

To the naked eye the space station is a slow-moving, very bright white dot that can be seen between the hours just after sunset and just before sunrise. This is due to reflected sunlight hitting the shiny bits of the station while you, on the ground, are still in the night shade of the limb of the earth. It will take anywhere from about 90 seconds to more than 3 minutes to cross the sky depending on its orbit and your location on earth. ISS can be hard to track using binoculars or a telescope but with careful planning, a little practice, and a dash of luck you can actually see the shape and structure of ISS through a modestly powerful instrument.

Lastly, if you are not into standing out in a field and looking at the sky, NASA provides live video feeds from the ISS to the public. My favorite is this high resolution feed accompanied by classical music from Amazing Space. I sometimes put it on my bedroom TV and just drift off to sleep with these amazing views from orbit.

I hope you get a chance to spot the ISS yourself; it is one of mankind’s crowning achievements and worth the 2 or 3 minutes to see for yourself. Let me know in the comments if you spot it!

Till next time!

Clear Skies,
Chris Fellows, Serenity Mobile Observatory

Find Chris on Facebook (or, if you’re lucky, at your campground). (Editor: Check out his amazing photos on his Facebook page!)


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1 year ago

Thank you very much for this interesting article. I’ve already downloaded your suggested links!

Serenity Mobile Observatory
1 year ago
Reply to  Sid

I’m Glad you enjoyed it! Clear skies!

1 year ago

Thank you very much Chris for your article and especially including the links to some of the ISS location software available for computers and cell phones. Can’t wait for clear skys. 🙂

Serenity Mobile Observatory
1 year ago
Reply to  alvin.e

You are very welcome Alvin, good luck and let me know if you spot ISS!