![]() ![]() The ISS will appear at 11 degrees above the horizon in SSW sky. Your best chance to see it is Thursday, December 3, at 5:46 p.m. It will take a few extra seconds to load, but it’s worth the wait. Over the next week and a half you'll have a couple good opportunties to see the International Space Station from San Diego as it's whizzes by overhead on its orbit of the Earth. So I did an animation of a Space Shuttle orbit that might help you see how this can be. ![]() That’s a tough concept wrap your head around … how something can be falling toward the Earth and never hit it. Early morning before sunrise is another good time. One might say the ISS is falling around the Earth, and gravity is what holds it in a circular orbit. When is the ISS visible in the night sky The best sightings of the International Space Station occur in the evening shortly after sunset, when the Sun has slipped below your horizon but there’s still enough light to reflect off the craft’s solar panels. There will be another good chance to see it on Saturday, December 5, at 5:40 p.m. It will fly up to 58 degrees over the horizon and be visible for four minutes before descending below the line of sight at about 30 degrees above the ENE horizon. And that’s just far enough to “miss” hitting the Earth and carry the ISS over the horizon. The ISS will appear at 11 degrees above the horizon in SSW sky. ![]() But its extreme horizontal speed of 27,724 kilometers per hour (17,227 mph) ensures that by the time it falls that distance the ISS has also moved over 8000 km (5000 miles) horizontally. So what keeps the ISS from falling back to Earth?Īnswer: The ISS is continuously falling toward the Earth. Gravity extends to that altitude (and beyond), and is only a few percent less than at ground level. ![]() It has a current total mass of over 400,000 kg, and is pulled downward by gravity with a force of 4 million newtons (about 1 million pounds). NASA uses that fuel on many spacecraft because it’s hypergolic - the two compounds ignite on contact, providing high reliability and no need for a “spark plug.”īy the way, your description of the ISS as “floating” is not quite accurate. The fuel used by the Zvezda Module is a highly reactive combination of nitrogen tetroxide (N 2O 4) which acts as the oxidizer, and monomethylhydrazine (CH 3NHNH 2) which is what gets oxidized (burned). Using a docked spacecraft is a “backup plan.” That can only be done if the spacecraft has fuel to spare, and they don’t usually carry much more than they need since unburned fuel is extra weight. The air gets pretty thin up there, but it’s still enough to cause friction and gradually reduce the speed of any orbiting object. Zvezda is always kept fueled for such purposes, and that fuel is re-supplied as needed by scheduled cargo shipments. Answer: The International Space Station (ISS), like all other objects in orbit, experiences a slight amount of air drag, even at an altitude of hundreds of kilometers. Note that the Zvezda Module is on the aft end of the ISS, opposite its direction of motion. There are two ways to do this … either by using an onboard thruster in the Zvezda Module (see graphic), or the engines of a spacecraft docked with the ISS. It is the third brightest object in the sky and easy to spot if you know when to look up. They also sometimes change the orbit in other directions to avoid being hit by dangerous pieces of space junk. Watch the International Space Station pass overhead from several thousand worldwide locations. NASA will provide live coverage of the upcoming return activities for the agency’s SpaceX Crew-4 mission to the International Space Station. So every once in awhile they need to boost its orbit back to where it should be. That’s exactly what happened with Sky Lab back in July 1979. Left unchecked, that loss of speed would eventually cause the ISS to fall back to Earth in a meteoric reentry and break up. Another great viewing opportunity assuming skies are clear will be on July, 14.Question: How does the International Space Station stay in orbit? Isn’t gravity always pulling it downward toward Earth? And if so, do they have to do anything special to keep it floating up there in space? - BT, Minoqua, WIĪnswer: The International Space Station (ISS), like all other objects in orbit, experiences a slight amount of air drag, even at an altitude of hundreds of kilometers. Here are some other viewing times of the ISS for Texoma within the next several days. Typically it will be the brightest object in the night sky (except for the Moon). International Space Station in Texoma (kswo) The space station looks like a fast-moving plane in the sky, but it will be seen as a steady not blinking white pinpoint of light. ![]()
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