How was New Horizons able to direct data so precisely back to Earth?












37














New Horizons is sending back images of Ultima Thule, 6.4 billion kilometres away. Barring having a very large power to send information back on a very large angle, it seems to me that the level of precision to send this information back so that it can be captured by an antenna on Earth is prohibitively hard to get. How is NASA accomplishing it?










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  • 5




    Related: it's standard procedure to supercool the receivers back on Earth, in freezers transparent to the wavelength to be received, to drastically reduce thermal noise. They can discern a very faint arriving signal.
    – Emilio M Bumachar
    16 hours ago






  • 1




    @EmilioMBumachar one of the biggest things we've done for detection accuracy is figure out how to link many radar dishes together into large arrays in order to increase the functional aperture of the detector. Basic optics dictates how sharply you can focus is dependent on the aperture of your camera. Only then can the sensors clearly "see" the spacecraft transmitting data. Also there is a high degree of redundancy in the data in order to perform error correction.
    – Aaron
    8 hours ago


















37














New Horizons is sending back images of Ultima Thule, 6.4 billion kilometres away. Barring having a very large power to send information back on a very large angle, it seems to me that the level of precision to send this information back so that it can be captured by an antenna on Earth is prohibitively hard to get. How is NASA accomplishing it?










share|improve this question









New contributor




user is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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  • 5




    Related: it's standard procedure to supercool the receivers back on Earth, in freezers transparent to the wavelength to be received, to drastically reduce thermal noise. They can discern a very faint arriving signal.
    – Emilio M Bumachar
    16 hours ago






  • 1




    @EmilioMBumachar one of the biggest things we've done for detection accuracy is figure out how to link many radar dishes together into large arrays in order to increase the functional aperture of the detector. Basic optics dictates how sharply you can focus is dependent on the aperture of your camera. Only then can the sensors clearly "see" the spacecraft transmitting data. Also there is a high degree of redundancy in the data in order to perform error correction.
    – Aaron
    8 hours ago
















37












37








37


2





New Horizons is sending back images of Ultima Thule, 6.4 billion kilometres away. Barring having a very large power to send information back on a very large angle, it seems to me that the level of precision to send this information back so that it can be captured by an antenna on Earth is prohibitively hard to get. How is NASA accomplishing it?










share|improve this question









New contributor




user is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











New Horizons is sending back images of Ultima Thule, 6.4 billion kilometres away. Barring having a very large power to send information back on a very large angle, it seems to me that the level of precision to send this information back so that it can be captured by an antenna on Earth is prohibitively hard to get. How is NASA accomplishing it?







nasa spacecraft new-horizons






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edited 56 mins ago







user













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asked yesterday









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  • 5




    Related: it's standard procedure to supercool the receivers back on Earth, in freezers transparent to the wavelength to be received, to drastically reduce thermal noise. They can discern a very faint arriving signal.
    – Emilio M Bumachar
    16 hours ago






  • 1




    @EmilioMBumachar one of the biggest things we've done for detection accuracy is figure out how to link many radar dishes together into large arrays in order to increase the functional aperture of the detector. Basic optics dictates how sharply you can focus is dependent on the aperture of your camera. Only then can the sensors clearly "see" the spacecraft transmitting data. Also there is a high degree of redundancy in the data in order to perform error correction.
    – Aaron
    8 hours ago
















  • 5




    Related: it's standard procedure to supercool the receivers back on Earth, in freezers transparent to the wavelength to be received, to drastically reduce thermal noise. They can discern a very faint arriving signal.
    – Emilio M Bumachar
    16 hours ago






  • 1




    @EmilioMBumachar one of the biggest things we've done for detection accuracy is figure out how to link many radar dishes together into large arrays in order to increase the functional aperture of the detector. Basic optics dictates how sharply you can focus is dependent on the aperture of your camera. Only then can the sensors clearly "see" the spacecraft transmitting data. Also there is a high degree of redundancy in the data in order to perform error correction.
    – Aaron
    8 hours ago










5




5




Related: it's standard procedure to supercool the receivers back on Earth, in freezers transparent to the wavelength to be received, to drastically reduce thermal noise. They can discern a very faint arriving signal.
– Emilio M Bumachar
16 hours ago




Related: it's standard procedure to supercool the receivers back on Earth, in freezers transparent to the wavelength to be received, to drastically reduce thermal noise. They can discern a very faint arriving signal.
– Emilio M Bumachar
16 hours ago




1




1




@EmilioMBumachar one of the biggest things we've done for detection accuracy is figure out how to link many radar dishes together into large arrays in order to increase the functional aperture of the detector. Basic optics dictates how sharply you can focus is dependent on the aperture of your camera. Only then can the sensors clearly "see" the spacecraft transmitting data. Also there is a high degree of redundancy in the data in order to perform error correction.
– Aaron
8 hours ago






@EmilioMBumachar one of the biggest things we've done for detection accuracy is figure out how to link many radar dishes together into large arrays in order to increase the functional aperture of the detector. Basic optics dictates how sharply you can focus is dependent on the aperture of your camera. Only then can the sensors clearly "see" the spacecraft transmitting data. Also there is a high degree of redundancy in the data in order to perform error correction.
– Aaron
8 hours ago












1 Answer
1






active

oldest

votes


















60














The high gain antenna of New Horizon as an opening angle of its beam of about 0.6°. That means, it has to be pointed at Earth with an error margin of 0.3°.
As a practical example, this is more like pointing a torch with a (focused) beam at a far target than aiming with a tiny Laser spot.



The antenna is fixed to the spacecraft, so that the whole space probe has to rotate (that's the reason there was no direct data download during the encounter with Pluto). Rotating is accomplished by its on-board thrusters that can be used to adjust rotation very precisely.



Now the only remaining point is to figure out were Earth is located. Luckily somebody installed a bright beacon light relatively close to Earth (better known as the Sun) that can be used to find it. From Pluto Earth is at most 1.3° off to either side of the Sun.



New Horizons is equipped with a star tracker - essentially a camera that takes images of the sky and some software that reads the position and brightness of stars and compares them with a map. If, for any reason, pointing the antenna at Earth fails the space probe can switch to its smaller medium gain antenna which can work even when missing Earth by up to 10°. Essentially this allows to operate in a pure Sun-tracking mode without knowing the precise orientation of the probe.



And, as a last backup, there is also an omnidirectional antenna that can receive commands under almost any conditions to help getting the spacecraft operational again. Due to its low gain, this antenna could be used during the initial phase of the flight only - after traveling more than a few AU the signal received is too weak to be useful.






share|improve this answer



















  • 13




    That bright beacon is particularly important for the medium gain antenna, especially just after the vehicle first wakes up after a long hibernation period. The medium gain antenna has a 10° half power beamwidth, so pointing the vehicle so the medium gain antenna points at that bright beacon means the vehicle is able to receive the command from the Earth that tells it where to point itself so the high gain antenna is pointed at the Earth.
    – David Hammen
    yesterday








  • 2




    In addition to rate gyros and star trackers, New Horizons is also equipped with bright beacon detectors, aka Sun sensors.
    – David Hammen
    yesterday










  • @david-hammen Thanks, I added the other antennas.
    – asdfex
    yesterday








  • 1




    I highly doubt the omni is in range anymore.
    – Joshua
    yesterday






  • 3




    @Joshua it appears not The low gain system was only intended to be used within 1AU. While there probably was some room to push it using a more powerful transmitter at its current distance or ~44AU an increase of ~2000x would be needed vs at 1AU. While Arecibo is a more powerful transmitter than any of NASAs normal radio telescopes, it's not that much more powerful. spaceflight101.com/newhorizons/spacecraft-overview
    – Dan Neely
    yesterday











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1 Answer
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1 Answer
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active

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active

oldest

votes









60














The high gain antenna of New Horizon as an opening angle of its beam of about 0.6°. That means, it has to be pointed at Earth with an error margin of 0.3°.
As a practical example, this is more like pointing a torch with a (focused) beam at a far target than aiming with a tiny Laser spot.



The antenna is fixed to the spacecraft, so that the whole space probe has to rotate (that's the reason there was no direct data download during the encounter with Pluto). Rotating is accomplished by its on-board thrusters that can be used to adjust rotation very precisely.



Now the only remaining point is to figure out were Earth is located. Luckily somebody installed a bright beacon light relatively close to Earth (better known as the Sun) that can be used to find it. From Pluto Earth is at most 1.3° off to either side of the Sun.



New Horizons is equipped with a star tracker - essentially a camera that takes images of the sky and some software that reads the position and brightness of stars and compares them with a map. If, for any reason, pointing the antenna at Earth fails the space probe can switch to its smaller medium gain antenna which can work even when missing Earth by up to 10°. Essentially this allows to operate in a pure Sun-tracking mode without knowing the precise orientation of the probe.



And, as a last backup, there is also an omnidirectional antenna that can receive commands under almost any conditions to help getting the spacecraft operational again. Due to its low gain, this antenna could be used during the initial phase of the flight only - after traveling more than a few AU the signal received is too weak to be useful.






share|improve this answer



















  • 13




    That bright beacon is particularly important for the medium gain antenna, especially just after the vehicle first wakes up after a long hibernation period. The medium gain antenna has a 10° half power beamwidth, so pointing the vehicle so the medium gain antenna points at that bright beacon means the vehicle is able to receive the command from the Earth that tells it where to point itself so the high gain antenna is pointed at the Earth.
    – David Hammen
    yesterday








  • 2




    In addition to rate gyros and star trackers, New Horizons is also equipped with bright beacon detectors, aka Sun sensors.
    – David Hammen
    yesterday










  • @david-hammen Thanks, I added the other antennas.
    – asdfex
    yesterday








  • 1




    I highly doubt the omni is in range anymore.
    – Joshua
    yesterday






  • 3




    @Joshua it appears not The low gain system was only intended to be used within 1AU. While there probably was some room to push it using a more powerful transmitter at its current distance or ~44AU an increase of ~2000x would be needed vs at 1AU. While Arecibo is a more powerful transmitter than any of NASAs normal radio telescopes, it's not that much more powerful. spaceflight101.com/newhorizons/spacecraft-overview
    – Dan Neely
    yesterday
















60














The high gain antenna of New Horizon as an opening angle of its beam of about 0.6°. That means, it has to be pointed at Earth with an error margin of 0.3°.
As a practical example, this is more like pointing a torch with a (focused) beam at a far target than aiming with a tiny Laser spot.



The antenna is fixed to the spacecraft, so that the whole space probe has to rotate (that's the reason there was no direct data download during the encounter with Pluto). Rotating is accomplished by its on-board thrusters that can be used to adjust rotation very precisely.



Now the only remaining point is to figure out were Earth is located. Luckily somebody installed a bright beacon light relatively close to Earth (better known as the Sun) that can be used to find it. From Pluto Earth is at most 1.3° off to either side of the Sun.



New Horizons is equipped with a star tracker - essentially a camera that takes images of the sky and some software that reads the position and brightness of stars and compares them with a map. If, for any reason, pointing the antenna at Earth fails the space probe can switch to its smaller medium gain antenna which can work even when missing Earth by up to 10°. Essentially this allows to operate in a pure Sun-tracking mode without knowing the precise orientation of the probe.



And, as a last backup, there is also an omnidirectional antenna that can receive commands under almost any conditions to help getting the spacecraft operational again. Due to its low gain, this antenna could be used during the initial phase of the flight only - after traveling more than a few AU the signal received is too weak to be useful.






share|improve this answer



















  • 13




    That bright beacon is particularly important for the medium gain antenna, especially just after the vehicle first wakes up after a long hibernation period. The medium gain antenna has a 10° half power beamwidth, so pointing the vehicle so the medium gain antenna points at that bright beacon means the vehicle is able to receive the command from the Earth that tells it where to point itself so the high gain antenna is pointed at the Earth.
    – David Hammen
    yesterday








  • 2




    In addition to rate gyros and star trackers, New Horizons is also equipped with bright beacon detectors, aka Sun sensors.
    – David Hammen
    yesterday










  • @david-hammen Thanks, I added the other antennas.
    – asdfex
    yesterday








  • 1




    I highly doubt the omni is in range anymore.
    – Joshua
    yesterday






  • 3




    @Joshua it appears not The low gain system was only intended to be used within 1AU. While there probably was some room to push it using a more powerful transmitter at its current distance or ~44AU an increase of ~2000x would be needed vs at 1AU. While Arecibo is a more powerful transmitter than any of NASAs normal radio telescopes, it's not that much more powerful. spaceflight101.com/newhorizons/spacecraft-overview
    – Dan Neely
    yesterday














60












60








60






The high gain antenna of New Horizon as an opening angle of its beam of about 0.6°. That means, it has to be pointed at Earth with an error margin of 0.3°.
As a practical example, this is more like pointing a torch with a (focused) beam at a far target than aiming with a tiny Laser spot.



The antenna is fixed to the spacecraft, so that the whole space probe has to rotate (that's the reason there was no direct data download during the encounter with Pluto). Rotating is accomplished by its on-board thrusters that can be used to adjust rotation very precisely.



Now the only remaining point is to figure out were Earth is located. Luckily somebody installed a bright beacon light relatively close to Earth (better known as the Sun) that can be used to find it. From Pluto Earth is at most 1.3° off to either side of the Sun.



New Horizons is equipped with a star tracker - essentially a camera that takes images of the sky and some software that reads the position and brightness of stars and compares them with a map. If, for any reason, pointing the antenna at Earth fails the space probe can switch to its smaller medium gain antenna which can work even when missing Earth by up to 10°. Essentially this allows to operate in a pure Sun-tracking mode without knowing the precise orientation of the probe.



And, as a last backup, there is also an omnidirectional antenna that can receive commands under almost any conditions to help getting the spacecraft operational again. Due to its low gain, this antenna could be used during the initial phase of the flight only - after traveling more than a few AU the signal received is too weak to be useful.






share|improve this answer














The high gain antenna of New Horizon as an opening angle of its beam of about 0.6°. That means, it has to be pointed at Earth with an error margin of 0.3°.
As a practical example, this is more like pointing a torch with a (focused) beam at a far target than aiming with a tiny Laser spot.



The antenna is fixed to the spacecraft, so that the whole space probe has to rotate (that's the reason there was no direct data download during the encounter with Pluto). Rotating is accomplished by its on-board thrusters that can be used to adjust rotation very precisely.



Now the only remaining point is to figure out were Earth is located. Luckily somebody installed a bright beacon light relatively close to Earth (better known as the Sun) that can be used to find it. From Pluto Earth is at most 1.3° off to either side of the Sun.



New Horizons is equipped with a star tracker - essentially a camera that takes images of the sky and some software that reads the position and brightness of stars and compares them with a map. If, for any reason, pointing the antenna at Earth fails the space probe can switch to its smaller medium gain antenna which can work even when missing Earth by up to 10°. Essentially this allows to operate in a pure Sun-tracking mode without knowing the precise orientation of the probe.



And, as a last backup, there is also an omnidirectional antenna that can receive commands under almost any conditions to help getting the spacecraft operational again. Due to its low gain, this antenna could be used during the initial phase of the flight only - after traveling more than a few AU the signal received is too weak to be useful.







share|improve this answer














share|improve this answer



share|improve this answer








edited 17 hours ago

























answered yesterday









asdfexasdfex

5,4591525




5,4591525








  • 13




    That bright beacon is particularly important for the medium gain antenna, especially just after the vehicle first wakes up after a long hibernation period. The medium gain antenna has a 10° half power beamwidth, so pointing the vehicle so the medium gain antenna points at that bright beacon means the vehicle is able to receive the command from the Earth that tells it where to point itself so the high gain antenna is pointed at the Earth.
    – David Hammen
    yesterday








  • 2




    In addition to rate gyros and star trackers, New Horizons is also equipped with bright beacon detectors, aka Sun sensors.
    – David Hammen
    yesterday










  • @david-hammen Thanks, I added the other antennas.
    – asdfex
    yesterday








  • 1




    I highly doubt the omni is in range anymore.
    – Joshua
    yesterday






  • 3




    @Joshua it appears not The low gain system was only intended to be used within 1AU. While there probably was some room to push it using a more powerful transmitter at its current distance or ~44AU an increase of ~2000x would be needed vs at 1AU. While Arecibo is a more powerful transmitter than any of NASAs normal radio telescopes, it's not that much more powerful. spaceflight101.com/newhorizons/spacecraft-overview
    – Dan Neely
    yesterday














  • 13




    That bright beacon is particularly important for the medium gain antenna, especially just after the vehicle first wakes up after a long hibernation period. The medium gain antenna has a 10° half power beamwidth, so pointing the vehicle so the medium gain antenna points at that bright beacon means the vehicle is able to receive the command from the Earth that tells it where to point itself so the high gain antenna is pointed at the Earth.
    – David Hammen
    yesterday








  • 2




    In addition to rate gyros and star trackers, New Horizons is also equipped with bright beacon detectors, aka Sun sensors.
    – David Hammen
    yesterday










  • @david-hammen Thanks, I added the other antennas.
    – asdfex
    yesterday








  • 1




    I highly doubt the omni is in range anymore.
    – Joshua
    yesterday






  • 3




    @Joshua it appears not The low gain system was only intended to be used within 1AU. While there probably was some room to push it using a more powerful transmitter at its current distance or ~44AU an increase of ~2000x would be needed vs at 1AU. While Arecibo is a more powerful transmitter than any of NASAs normal radio telescopes, it's not that much more powerful. spaceflight101.com/newhorizons/spacecraft-overview
    – Dan Neely
    yesterday








13




13




That bright beacon is particularly important for the medium gain antenna, especially just after the vehicle first wakes up after a long hibernation period. The medium gain antenna has a 10° half power beamwidth, so pointing the vehicle so the medium gain antenna points at that bright beacon means the vehicle is able to receive the command from the Earth that tells it where to point itself so the high gain antenna is pointed at the Earth.
– David Hammen
yesterday






That bright beacon is particularly important for the medium gain antenna, especially just after the vehicle first wakes up after a long hibernation period. The medium gain antenna has a 10° half power beamwidth, so pointing the vehicle so the medium gain antenna points at that bright beacon means the vehicle is able to receive the command from the Earth that tells it where to point itself so the high gain antenna is pointed at the Earth.
– David Hammen
yesterday






2




2




In addition to rate gyros and star trackers, New Horizons is also equipped with bright beacon detectors, aka Sun sensors.
– David Hammen
yesterday




In addition to rate gyros and star trackers, New Horizons is also equipped with bright beacon detectors, aka Sun sensors.
– David Hammen
yesterday












@david-hammen Thanks, I added the other antennas.
– asdfex
yesterday






@david-hammen Thanks, I added the other antennas.
– asdfex
yesterday






1




1




I highly doubt the omni is in range anymore.
– Joshua
yesterday




I highly doubt the omni is in range anymore.
– Joshua
yesterday




3




3




@Joshua it appears not The low gain system was only intended to be used within 1AU. While there probably was some room to push it using a more powerful transmitter at its current distance or ~44AU an increase of ~2000x would be needed vs at 1AU. While Arecibo is a more powerful transmitter than any of NASAs normal radio telescopes, it's not that much more powerful. spaceflight101.com/newhorizons/spacecraft-overview
– Dan Neely
yesterday




@Joshua it appears not The low gain system was only intended to be used within 1AU. While there probably was some room to push it using a more powerful transmitter at its current distance or ~44AU an increase of ~2000x would be needed vs at 1AU. While Arecibo is a more powerful transmitter than any of NASAs normal radio telescopes, it's not that much more powerful. spaceflight101.com/newhorizons/spacecraft-overview
– Dan Neely
yesterday










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