A NASA laser just fired successfully in a deep-space test.
On Nov. 14, NASA picked up a laser signal fired from an instrument that launched with the Psyche spacecraft, which is currently more than 10 million miles (16 million kilometers) from Earth and heading toward a mysterious metal asteroid. (The spacecraft is at more than 40 times the average distance of Earth's moon, and still voyaging afar.)
The moment marked the first successful test of NASA's Deep Space Optical Communications (DSOC) system, a next-generation comms link that sends information not by radio waves but instead by laser light. It's part of a series of tests NASA is doing to speed up communications in deep space, on different missions.
"Achieving first light is a tremendous achievement. The ground systems successfully detected the deep space laser photons from DSOC," Abi Biswas, the system's project technologist at NASA's Jet Propulsion Laboratory (JPL) in Southern California, said in an agency statement.
"And we were also able to send some data, meaning we were able to exchange 'bits of light' from and to deep space," Biswas added.
Other missions have tried out laser comms in Earth orbit or on the way to the moon and back, but DSOC gives laser communications its trickiest, most distant test yet. If it's successful, NASA officials expect that astronauts of the coming decades, bound for the moon or for Mars, may use laser light as their means of taking with ground control.
This DSOC test began in California, at JPL's Table Mountain Facility. There, in the hills outside Los Angeles, engineers switched on an uplink beacon, a near-infrared laser pointed in Psyche's direction. About 50 seconds later, a transceiver on Psyche received the laser and relayed its own laser signal back to Palomar Observatory, near San Diego.
The task requires astronomical precision, and automated guidance systems help aim Psyche's own laser. But should the test work out, the benefits are high: Because laser light has shorter wavelengths than radio waves, using optical light would allow space missions to send 10 to 100 times more information per unit time than they currently do.
The Nov. 14 test marked "first light" for DSOC, and engineers will continue to test the system as Psyche voyages to its namesake asteroid, which resides in the asteroid belt between Mars and Jupiter. Psyche should get there in 2029, then spend 29 months surveying the bizarre metallic world.
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Rahul Rao is a graduate of New York University's SHERP and a freelance science writer, regularly covering physics, space, and infrastructure. His work has appeared in Gizmodo, Popular Science, Inverse, IEEE Spectrum, and Continuum. He enjoys riding trains for fun, and he has seen every surviving episode of Doctor Who. He holds a masters degree in science writing from New York University's Science, Health and Environmental Reporting Program (SHERP) and earned a bachelors degree from Vanderbilt University, where he studied English and physics.
I wonder how much that laser spot grew in 10 million miles.Reply
Now we can download much faster. But we still have 30 yr old data no one has seen yet.
Perhaps A.I. can help with this.
Beam divergence is limited by diffraction. Divergence angle in radians = wavelength divided by (pi times beam diameter).Reply
The beam is "near infrared" which runs from 860 nm up to 2500 nm. I can't find the exact wavelength but on a graph I could see that at 860 the Earth's atmosphere is 100% transparent, no so for the entire rest of the band.
The laser beam coming from the spacecraft is 20 cm in diameter and the distance right now is 16 million km.
Beam spread in radians = 8.60e-7 / (3.14 * .02) = 14 micro radians.
At 16e6 km the beam width would be 219 km.
This is why they are using the Hale telescope on Mt Palomar to receive the data.
Thank you. I had no idea the beam was that large.Reply
I'm sure it will improve and give us higher transfer rates. But we will still have the delay.
We need some kind of "space shaft", to connect instant motion at both ends.
Any solid shaft depends upon electromagnetism between atoms, as one outer shell electron presses against a neighboring outer shell electron. The movement of a sold shaft cannot be any faster than the speed of light.Reply
Seems like the only way to get faster communication would be to really master the ability to use entanglement. Not sure we will ever get that working for us.Reply
I think a rotating shaft has a quantum condensate property. Not all condensate properties, but it has the same spacetime thru out it's structure. A singularity sorta. In a time and motion sense.Reply
A twist on one end, gives the same instant twist on the other end.....at a distance. And all along the distance. A space time synchronizer.
Unlike gases and liquids, the metal solid has locked and fixed bonding structures. Even in Ag, the vast majority of electrons are locked and bonded. And I think there is more to just electron sharing involved with solids. The atomic EM fields have shapes and densities and fit, and not fit, halfway fit, due to these structures.......sorta like locks and keys. Shape fit bonds.
If there were a shaft between here and the moon, I believe a twist would have no delay. A push might take a delay, but I don't think a twist would. And I don't believe a change in the twist would delay either. But no one else thinks this way and I know of no way to try it.
But rotating shafts provide this function with mechanical analog computers. Or any timed or ratio-ed motion.
Too bad we can't lock and align space like that.
I don't understand why you think that a solid shaft moves without distortion when subjected to torque. Have you ever turned the head off of a screw by trying to turn it into something the is providing too much resistance? And the same with longitudinal forces, which create waves that travel at the speed of sound in the material. Just listening to a bell ring should tell you that the whole object does not move as a single, undeformable part when struck at one point on its surface. Solids do not behave like you posted. They deform and can spring back, stay deformed or even break when forces are applied.Reply
Entanglement cannot be used to transmit information. The reason is that the sender has no way of choosing the quantum state of the particle. The receiver can look at their particle and know what the sender's quantum state was. They could use this to coordinate activities thus qualifies as "information". Problem is, that information did not travel at the speed of light, it traveled in the space traveler's vehicle to get to the destination at less than the speed of light.Reply
A solid shaft made of pure diamond has a speed of sound of 18,350 meters per second. To communicate with the Moon, it would take 11.6 hours to get an answer. To the Sun and back is 378 days. To the nearest star 138,000 years.Reply
Oh, I have seen solid distortion. But what I have seen takes a certain level of force to distort. And I understand sound propagation and the distortion of solids with it. And have used E fields to distort solid structures. But it seems distortions take certain stimulation levels and stimulation rates for it. I understand temp causes distortion too. Are we now saying any force and any motion causes distortion in solids? I was not aware of that.Reply
So the concept of a solid is not strictly a solid. A solid can not be accelerated without distortion? So one end of the shaft is distorted and has a delay in the torque applied from the other end? A delay in the twist. The twist takes time to reach the other end.
Can you measure this?