The angle for the quasar is subtracted from the angle of the spacecraft, giving the angular separation of the quasar and the spacecraft. That angle is accurate to about five to ten nanoradians, which means when the spacecraft is near Mars, say million kilometers away, it can determine the position of the spacecraft to within one kilometer 0. During the entry, descent and landing phase of the Mars Exploration Rover mission, engineers listened anxiously for distinct tones that indicated when steps in the process were activated; one sound indicated the parachute deployed, while another signaled that the airbags had inflated.
These sounds were a series of basic, special individual radio tones. The Mars Science Laboratory spacecraft transmitted in X-band during its entry, descent and landing process, which was the expected path for confirmation of the initial events in the process.
Due to signal strength constraints, these transmissions were simple tones, comparable to semaphore codes, rather than full telemetry. The Deep Space Network listened for these direct-to-Earth transmissions. By then, the bent-pipe relay via Odyssey had begun. Not only does the rover send messages directly to the DSN stations, but it is also able to uplink information to other spacecraft orbiting Mars, utilizing mainly the Mars Reconnaissance Orbiter and Mars Odyssey if necessary spacecraft as messengers that pass along news to Earth for the rover.
The respective spacecraft mainly "talk" via their UHF antennas. The benefits of using the orbiting spacecraft are that the orbiters are closer to the rover than the DSN antennas on Earth and the orbiters have Earth in their field of view for much longer time periods than the rover on the ground.
The rover communicates with the orbiters and the DSN through radio waves. They communicate with each other through X-band, which are radio waves at a much higher frequency than radio waves used for FM stations. The radio waves to and from the rover are sent through the orbiters using UHF antennas, which are close-range antennas that are like walkie-talkies compared to the long range of low-gain and high-gain antennas.
Only Odyssey relayed the information immediately, however. The other two orbiters recorded Mars Science Laboratory data from the Mars Science Laboratory spacecraft, holding it onboard, and sending it to Earth hours later. Mars Reconnaisance Orbiter even captured images of the spacecraft on its parachute during entry, descent and landing.
The cruise stage had two antennas that were used to communicate with the Earth. Actually, radio waves travel very quickly through space. Radio waves are a kind of electromagnetic radiation, and thus they move at the speed of light. The speed of light is a little less than , km per second. At that speed, a beam of light could go around the Earth at the equator more then 7 times in a second.
Sometimes they are on the same side of the sun and, at closest approach, light only takes about 3 minutes to travel between the two. Sometimes they are on opposite sides of the sun and it takes up to about 22 minutes. As to the other responses, the difference between speed of light and radio waves is negligible over these short distances. Depends on the positionsame of earth and Mars. If we are on the same side of sun we are closer. If the planets are on opposite sides of sun.
The sun is closer. The sun distance from Earth is relatively constant. Mars is not. Varges, we are not necessarily the same side of the sun at the same time — so the longest time is for when Earth and Mars are degrees opposite each other and both at aphelion, and the shortest would be when we are both the same side, with Mars at perihelion and Earth at aphelion.
Now you are making sense, but at that point how much longer will it take the suns light to reach mars? Well, you have to remember that both Earth and Mars are moving at different speeds while the rocket is en route. Nobody is suggesting that there need to be fundamental changes in physics here. I just want to establish some facts here for those who are confused about physics.
That includes visible light, radio waves, and so forth. The speed of light in matter can vary, but in this case that is not important since all the space between mars, the earth, and the sun is vacuum. There is no air in space. If earth and Mars are traveling in different orbits around our sun ,their distances between them is continually changing and so will be the communication speed and all this makes it even more complicated on a permanent basis to figure this out just a bit to much for my math capabilities I really appreciate the skills of the modern scientists to make this all possible.
You are all the frontiersmen and women of humanity……thanks! I was having a discussion with my Circuits professor about the speed of communication to the Rover being faster than light. My professor and I wondered how that was possible.
Thanks for all the great Info. Bulldog6 Through quantum entanglement that would be possible however it has only been preformed on particles, scientists are yet to find a way for this to be used in a wave which is what would need to be done to communicate with the Rover at faster than light communication.
For now communication with the Mars Rover happens at the speed of light until a better understanding of quantum entanglement comes into existence. Can We transmit using light? Radio signals are a light wave and travel at the same speed as the light emitted from a laser.
Since we have established that light and radio waves go at the same speed, it would make no differences. Communications The Mars rover, Perseverance, has three antennas that serve as both its "voice" and its "ears. Having multiple antennas provides operational flexibility and back-up options just in case they are needed. Because the rover and orbiter antennas are within close range of each other, they act a little like walkie-talkies compared to the long-range telecommunications with Earth provided by the low-gain and high-gain antennas.
It generally takes about 5 to 20 minutes for a radio signal to travel the distance between Mars and Earth, depending on planet positions.
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