In In The Life of The ISS – Question Time
This post is dedicated to our friend Mihaela from Facebook that recently asked us a question that is partially related to the International Space Station (ISS). The Question was…
How many sunrises can an astronaut see from an orbiting space station, if it orbits the Earth in 90 minutes, and why?
This is a brilliant question and thank you Mihaela for asking us to look into it for you. I will be going through two parts to answering this. The first part is the straight forward answer, we will then go through a little more information about the ISS with some visulisations, that will help see why the aforementioned occurs. I have also used the ISS as an example as this is the most commonly known space station (seriously, isn’t it pretty cool we have space stations just whipping above us as we speak), plus there are some great apps available that allow you to track the ISS.
The Short Answer…
The ISS takes 92 minutes to orbit the earth once. Where as somewhere on Earth takes 24 hours to complete a full rotation and we see one sun rise and one sunset.
As it takes approximately 92 minutes for the ISS to complete and orbit, this means that every 45 minutes or so they will witness a sunrise or a sunset as they effectively pass over the point that Earth would be having a sun rise or a sun set at that particular time.
This means, over the course of 24 hours (Earth’s full rotation) the ISS will observe between 15 and 16 sun rises and sunsets.
Now a little more information on the ISS
The space station is made of many pieces. The pieces were put together in space by astronauts. The space station’s orbit is about 220 miles above Earth. NASA uses the station to learn about living and working in space. These lessons will help NASA explore space.
Questions and Facts
How Old Is the Space Station?
The first piece of the International Space Station was launched in 1998. A Russian rocket launched that piece. After that, more pieces were added. Two years later, the station was ready for people. The first crew arrived on November 2, 2000. People have lived on the space station ever since. Over time more pieces have been added. NASA and its partners around the world finished the space station in 2011.
How Big Is the Space Station?
The space station is as big inside as a house with five bedrooms. It has two bathrooms, a gymnasium and a big bay window. Six people are able to live there. It weighs almost a million pounds. It is big enough to cover a football field including the end zones. It has science labs from the United States, Russia, Japan and Europe.
What Are the Parts of the Space Station?
The space station has many parts. The parts are called modules. The first modules had parts needed to make the space station work. Astronauts also lived in those modules. Modules called “nodes” connect parts of the station to each other. Labs on the space station let astronauts do research.
On the sides of the space station are solar arrays. These arrays collect energy from the sun. They turn sunlight into electricity. Robot arms are attached outside. The robot arms helped to build the space station. They also can move astronauts around outside and control science experiments.
Airlocks on the space station are like doors. Astronauts use them to go outside on spacewalks.
Docking ports are like doors, too. The ports allow visiting spacecraft to connect to the space station. New crews and visitors enter the station through the docking ports. Astronauts fly to the space station on the Russian Soyuz. The crew members use the ports to move supplies onto the station.
Why Is the Space Station Important?
The space station is a home in orbit. People have lived in space every day since the year 2000. The space station’s labs are where crew members do research. This research could not be done on Earth.
Scientists study what happens to people when they live in space. NASA has learned how to keep a spacecraft working for a long time. These lessons will be important in the future.
NASA has a plan to send humans deeper into space than ever before. The space station is one of the first steps. NASA will use lessons from the space station to get astronauts ready for the journey ahead.
Some Quick Facts about the ISS
- 1. It took an astounding 136 space flights on seven different types of launch vehicles to build it.
- 2. It flies at 4.791 miles per second (7.71 km/s). That’s fast enough to go to the Moon and back in about a day.
- 3. It weighs almost 1 million pounds including visiting spacecraft. Picture 120,000 gallons of milk in supermarket cartons in your mind.
- 4. It has 8 miles of wire just to connect the electrical power system. That will be enough to connect a hair dryer in Newark, New Jersey, to a power plug in New York City.
- 5. It has a complete surface area the size of a US football field, which actually makes it almost as large as the Tantive IV, the Corellian Corvette that carried Princess Leia.
- 6. It has more livable space than a 6-bedroom house.
- 7. It has two bathrooms, a gymnasium and a 360-degree bay window.
- 8. It’s been the spaceport for 89 Russian Soyuz spacecraft, 37 Space Shuttle missions, three SpaceX Dragons, four Japanese HTV cargo spacecraft, and four European ATV cargo spacecraft.
- 9. All its research experiments and spacecraft systems are housed in a bit more than one hundred telephone-booth sized racks.
- 10. The US solar array surface area on the is 38,400 sq. feet (.88 acre), which is large enough to cover 8 basketball courts
- 11. According to NASA, “there are 52 computers controlling the ISS.” Just for the US segment, there are “1.5 million lines of flight software code run on 44 computers communicating via 100 data networks transferring 400,000 signals.”
- 12. Its internal pressurized volume is 32,333 cubic feet, which is about the same of a Jumbo Boeing 747.
- 13. The ISS crews have eaten about 25,000 meals since 2000. That’s a staggering “seven tons of supplies per three astronauts for six months.” That’s 32,558 Big Macs.
- 14. 211 people from 15 countries have visited the ISS so far.
- 15. When it reaches the end of its life, some of the most modern Russian modules—like Nauka—will be reused to make a third space station to support interplanetary mission to Mars, the Moon and Saturn, serving as a launching and return point.
Some Questions Answered by the NASA Team
Do you believe in that the design of the ISS will cause a problem in case of a meteor shower? Why?
That’s a really good question. The space environment is a very harsh environment: there’s radiation and micrometeorite strikes, and other things in the environment that cause it to be very hazardous. So, one of the things that we’ve designed the space station for is to protect the astronauts against micrometeorite striking the outer shell of the space station. Now, in doing so, the basic design philosophy of the pressurized modules has been to develop an inner shell, which contains the pressurized interior of the space station, and then a layer of insulation around that inner shell, and then an outer armor plating, if you will, to the exterior. And what that does is protects against small pieces of debris that strike the station and can cause leaks. Now, for larger pieces of debris: they actually track them and have to actually move the space station out of the way of the larger pieces that could cause serious damage to the station.
What kind of contingency plan does the ISS have in case of an emergency? How long do life support systems on board last for the stranded astronauts? Is there such a thing as an emergency launch to the ISS using the current space shuttles?
Well, there are several redundant systems on the space station, which really enable the astronauts to survive for long periods of time without a space shuttle or a Russian re-supply ship coming to bring additional supplies. Now, in the event of an outright emergency, where the lives of the astronauts were threatened, they would have to evacuate the space station using the Soyuz module, but the life support systems themselves are designed to last for months at a time without a re-supply ship.
What would you say to date has been the greatest benefit to mankind from the space station, and what is its predicted benefits?
Well, I think it’s all a matter of judgment, but to me the greatest benefit of the space station is the international cooperation to date that we’ve had with over 16 different countries contributing to the International Space Station; countries that were at one time, enemies of each other, have now come together to do something that will benefit mankind. I think down the road the space station will bring great leaps in science, in medical fields, in the materials manufacturing fields, and it will also teach us a lot about long duration human space flight so that we can expand our civilization beyond Earth.
Why is the center truss section called S-Zero?
That’s actually a really good question, because the trusses are named for whether they’re on the starboard side or the port side; so you have S-Zero, S-One, P-One, S-Three, P-Three, P-Four, S-Four, P-Five, S-Five. Well, S-Zero being in the middle, I guess they couldn’t decide whether to call it S-Zero or P-Zero, and maybe they flipped a coin or whatever else and decided to call it S-Zero, but it’s actually in the center, it’s not on the starboard side or the port side, so it could have just as easily been named P-Zero.
Does the International Space Station have any hardware or machines that were specifically invented for it and cannot be found anywhere else? What are they?
Well, the International Space Station has lots of unique hardware elements that were designed specifically for the International Space Station. They also use off-the-shelf technology when possible; one instance of that is the cameras that they use on the space station for the interior of the space station are actually just off-the-shelf camcorders. But, some, there’s certainly a great amount of technology that was developed specifically for the International Space Station to function specifically in the space environment. I think one of the best examples of that is the Canadian robotic arm. The Canadian robotic arm was developed specifically for the International Space Station and fills the task of actually constructing the International Space Station, and it doesn’t even function in the Earth environment in the one-G conditions that we have here on Earth.
When will the International Space Station be completed?
Well also that’s a very interesting question. The core complete milestone that we are reaching for right now is due in the mid-2004 timeframe. Now, after we finish building what’s essentially the core of the International Space Station then we have a lot of additional options to add elements developed by international partners, and other additional features that we might want to add. The fact that the space station was designed the way it was allows us to once we get to the core complete milestone to expand it to provide lots of additional capabilities.
Which ISS docking port is being used by the Soyuz TM-34 spacecraft? Also, where on the station will Endeavour and Leonardo dock?
Well, the Soyuz module is nominally docked to the end of the Russian service module. Now, there are additional docking ports on the Russian functional cargo block, I’m sorry, on the bottom of the service module, where the Soyuz modules can be docked. And when they bring a second one up onto orbit in order to switch out the first one when they have to replace them, they actually have to move one of the Soyuz modules from the end of the service module to the bottom of the service module, and the second service module goes on to the end. The space shuttle, on the other hand, docks to the American side of the space station, to the Destiny laboratory. And the MPLM, Leonardo, in this case, is docked to Node-1, which was also built by an American company, Boeing.
Is it possible to give the times and locations of when the ISS passes over Central California?
Well, it’s actually possible to find out when the space station will be passing over your head no matter where you live, and there’s a website, it’s http://spaceflight.nasa.gov, and if you go that website, you can follow links and actually no matter what city you are in the country, you can find out when the space station will be traveling overhead.
With respect to the space station, why can’t we just shoot the trash off towards the sun instead of bringing it back to Earth?
Well, that’s actually a question that I used to wonder about when I was growing up, why didn’t we just put all the trash into the sun to save our garbage problems here on Earth. Unfortunately, it would take a lot of rocket power to get anything to the Sun, and so it’s sort of a limiting factor to be able to launch something out the sphere of influence of the Earth. Now, the trash on the International Space Station, not all of it is brought back to Earth. Some of it is placed in the Russian Progress modules, which are sent on a trajectory into the Earth’s atmosphere that burns it back up. So it’s not all brought back to Earth, just some of it in the MPLM modules.
After the completion of the ISS, how much will it contribute to the flight of humans to Mars, and return trips to the Moon?
Well, this kind of goes with the earlier question, about what the benefits of the International Space Station are. If we’re going to go to Mars, or spend long periods of time on the Moon, we have to learn what the effects of long term space flight is going to be on our astronauts. We don’t have a lot of information about what the space environment does to our astronauts, beyond, say six months. There are astronauts, particularly from Russia, who have spend more time than that in space, but very few, so we don’t have a large amount of data, and it’d be very risky to send astronauts to Mars, to spend say, a year and a half outside of the Earth environment, or more, without knowing exactly what the effects of the long term exposure to space would be. So, the International Space Station in addition to us just developing the technology to live in space for large amounts of time, it gives us the information that we need about how long astronauts can safely stay in space.
Is it possible to use a flywheel mechanism to produce power for the space station? Have there been any experiments using this technology to produce power in space?
Well, it’s actually not possible to use flywheels to generate power in the classical sense, but you can use flywheels to store power. So, you would have to use some other source to generate the power, but then to store it you could spin up flywheels and then use the kinetic energy from the flywheels to actually store energy. But because the power requirements of the space station are so large, it’s a lot more practical for us to use batteries to store power on the station. So, the answer to the question is no, we don’t use flywheels to store power.
How many different civilian contracting companies, on average, participate in the building of one of our space station modules?
Well, most of the American space station modules were developed and built by the prime contractor for the space station, which is Boeing. Now, Boeing has dozens, if not hundreds of subcontractors that it uses to build everything from the smallest screw used on the space station to a complex computer, or a solar array. So, there’s one prime contractor, but dozens, if not hundreds of subcontractors.
When the space station needs to make an orbital adjustment, do the occupants of the space station feel the movement of the adjustment?
Well, the reason why I think that’s such a good question is because it really highlights one of the most fundamental laws of physics we have, and there are basically three laws of physics that Isaac Newton postulated hundreds of years ago, and one of those laws it that force equals mass times acceleration. Now, the key thing about these laws is that no matter where you are in the universe, they are true. So whether you’re on Earth or whether you’re in space, these laws are true. Now, this particular law, force equals mass plus acceleration, when you press the gas pedal in your car, your car accelerates, you go from say, 55 miles an hour to 60 miles an hour. That acceleration is what causes you to feel that force. Now, in space, when they fire the thrusters on the space station, the space station also accelerates. But the acceleration is generally very, very small. So sometimes the astronauts might not notice the space station is accelerating. But that also brings in another interesting point, in what they might see, since the astronauts are floating free with respect to the space station, that when the space station fires it thrusters, the space station would move, and the astronauts, not touching one of the surfaces, would not move, so they would see the space station actually moving around them.
During a 24 hour period, how many times does the ISS orbit the Earth?
Well, the space station orbits Earth about every 90 minutes, so that means in a 24 hour day, the space station orbits approximately 16 times.
In operating, maintaining, and troubleshooting problems on the ISS, how involved does the ISS crew get versus the control center team?
Well, that’s a very good question. NASA has an entire army of people supporting the operations of the International Space Station. Of course, the astronauts are often the first line of defense, and especially in emergency situations, they have to make quick, critical decisions that will allow everybody to be safe. Now, the mission control people are a huge part of supporting that and laying out those plans for the emergency situations. But, in the event that something goes wrong on the station, NASA has the ability to go back to the people who actually designed the hardware and ask them what they think about the problem, and if it’s something they might have seen before in ground testing. So it’s a collaborative effort across all of the different countries that make up the hardware that we use on the International Space Station.
On certain days we are able to visualize the space station as it seems to streak across the sky. How fast is the ISS traveling?
Well, in order for the space station to stay in orbit, it has to travel at seven kilometers per second, which the equivalent in miles per hour, is around 15,500 miles per hour. So that’s pretty fast!
I hope you enjoyed this post and Mihaela, I hope this answered your question and then some more 🙂 thank you so so much for the question. If you or anyone else has any more questions please let us know on our Scientia facebook page or use the forums on Scientia to start your own thread.
– Credit and Resource –
NASA
In The Life of The ISS
