How are objects tracked in space?

Question

Like how do we know where mars exactly is? What kind of mapping system is used to get there. I imagine it is a little more complicated then point and shoot.

Answer 1

At first I thought you meant spacecraft when you said objects, but then you specified Mars, so I guess you mean natural objects like planets and asteroids. It is complicated since the planets are always moving. For thousands of years people had been watching the sky and knew that planets moved and stars did not. You can just see them as stars that are not always in the sample place in the sky and people had been plotting their positions for centuries, trying to explain how they moved, but not until Kepler did they have a good idea. In particular, Kepler's 3rd law tells us the ratios of the planets distances from the Sun. For example it tells us that Jupiter is 5 times as far from the Sun as Earth. The trick was to know any one planet's distance so we could use Kepler's 3rd law to tell us all the distances. Before the space age, the best measurement was of an asteroid which passed close enough to Earth to show a slightly different position from different places on Earth due to parallax. Direct measurement of the parallax angle determined that asteroids distance from Earth and from the all the other distances fell out of Kepler's 3rd law.

Answer 2

Hi. Objects in near Earth orbit are tracked by radar. Objects like planets, comets, asteroids, etc. are tracked by calculating the orbits based on a series of observations. Three or more positions can give a pretty good idea of where the object will be at a later time. More observations give more precise calculations.

Answer 3

They point a "laser" at it and when it bounces back, they can tell the distance by how long it takes to get there and back (when they know the speed of the laser beam). Same thing for getting the geography of the planet, they set a satellite to go around it that shoots consistent beams and makes computerized maps as they bounce back. Very very sophisticated technology.

Answer 4

satellites which are used for that purpose, can track anything in their range.

Answer 5

"The US Air Force Space Command, which tracks objects in space"

"The 1st Space Control Squadron (1st SPCS) of the U.S. Air Force Space Command, located inside Cheyenne Mountain Air Force Station in Colorado Springs, is responsible for tracking objects larger than 10 centimeters orbiting Earth. Five 11-person crews work around the clock, 365 days a year, to constantly track these objects. They task the Space Surveillance Network, a worldwide network of 19 space surveillance sensors (radar and optical telescopes, both military and civilian) to observe the objects. Then the crews use computers within the Cheyenne Mountain complex to match sensor observations to the more than 8,500 man-made orbiting objects and update the position of each one. These updates form the Space Catalog, a comprehensive listing of the numbers, types, and orbits of man-made objects in space.

NASA offers to the general public on its website, the opportunity to track various satellites. Click here to go to NASA's J-Track. USSTRATCOM does not make landfall predictions. Current capabilities and procedures give us a limited ability to predict within a 30-minute, 6,000-mile window when and where a particular object will re-enter the Earth's upper atmosphere.

Objects are tracked throughout their orbit life, with the results posted in the Space Catalog. When an object appears to be re-entering within seven days, orbital analysts in Cheyenne Mountain's Space Control Center (SCC) will increase sensor tasking (monitoring) and begin to project a specific re-entry time and location. At the four-day point, a monitor run is accomplished once a shift or three times a day. Messages indicating the calculated re-entry time and location are transmitted to forward users and customers at the four-, three-, two- and one-day points. Starting at the 24-hour point, the object is monitored at the highest level of scrutiny, with processing at the 12, six and two-hour points. Again, ground traces and messages are transmitted. The object is monitored throughout re-entry."

"To track the objects, the squadron uses data captured by the Space Surveillance Network, a worldwide collection of 19 space surveillance sensors -- radar and optical telescopes, both military and civilian. Inside Cheyenne Mountain, the squadron correlates the sensor data to the orbiting objects and updates the position of each one.

According to Thurston, the sensors can track satellites in a low-earth orbit down to a size of 10 centimeters. In high-earth orbit, Thurston said the ground-based Electro-Optical Deep Space Surveillance (GEODSS) sites, which use 40-inch telescopes, can track a satellite the size of a basketball at 35,000 kilometers.

As a historical data analyst, it is Thurston's job to use the data captured by radar sites to match up objects in space with their launches. For example, last December the center used data to match an object with an experimental satellite launched in June 1966.

The satellite, which measures 28 inches in diameter, stopped working in 1967. Tracking facilities were limited then, Thurston said, so once it stopped sending data, the Air Force had no way to track it.

"It had been floating around up there," Thurston said.

The oldest object tracked by the 1st SPCS is Vanguard 1, a 6-inch sphere launched from the Air Force Eastern Test Range (AFETR) on March 17, 1958. The largest object is the international space station.

The lost screwdriver
The objects aren't always satellites. One was a screwdriver that was lost during a 1985 space shuttle mission.

The space shuttle Discovery launched in August 1985 to deploy three communications satellites and to make repairs on LEASAT-3, which had been deployed from an earlier shuttle mission but was stranded in a low-earth orbit. After repairs, LEASAT-3 was successfully boosted into the proper orbit, and the sailing screwdriver burned up as it re-entered the atmosphere in February of 1986.


The 1st Space Control Squadron unit patchThe squadron is composed of roughly 120 military, civilian and contractor personnel assigned to the unit. Thurston is a civilian employee, but he started working at the SCC when he was an active-duty airman. He retired from the Air Force eight years ago with the rank of technical sergeant.

Five crews, staffed by six active-duty military personnel and two contractors, work in the Space Control Center 24 hours a day. The squadron also has 32 personnel in its Space Analysis Center, where Thurston works.

According to the Air Force, only a small amount of debris exists where the shuttle orbits and the likelihood of a "significant collision" between a piece of debris and the shuttle is extremely remote.

However, if it did happen, the impact would not be good. According to Thurston, satellites in orbit at 350 kilometers altitude, the altitude at which the ISS and most shuttle missions orbit, travel at 7.7 kilometers a second, or more than 16,000 mph.

Thurston said his job is very interesting and he enjoys working in Cheyenne Mountain -- and he is truly inside. The center is located deep in the mountain and is protected by 25-ton blast doors. Constructed during the Cold War, it was built to withstand a limited nuclear strike and rests on more than 1,300 three-foot high steel springs, which are supposed to help dampen an explosion. And despite the location, there are no lovely mountain views.

"I brought my wife in and she said, 'I don't know how you can work in here,'" he said."

"Re-entry Assessment is an "inexact science." It is virtually impossible to precisely predict where and when space debris will impact. This is due to limitations in our tracking system as well as environmental factors that impact on the debris. Most of our satellite tracking radar are located in the Northern Hemisphere, making continuous orbit coverage impossible. Consequently, a returning satellite could be outside sensor coverage for several hours.

Environmental factors acting on an object's orbit could include variations in the gravitational field of the land mass and ocean areas, solar radiation pressure and atmospheric drag. (Objects re-entering may skip off the Earth's atmosphere, much as a stone skipped across a pond, causing it to impact much further away than originally forecast.) Consequently, USSPACECOM does not give warning to civilian populations on point of impact for reentering objects."