NASA's asteroid hunter Psyche, recently launched into space, is designed to give us a glimpse of a body that could resemble the depths of the Earth, where we will never be able to reach. However, an instrument that accompanies it on its journey is exciting scientists specialized in a completely different field: that of space communications. Since the dawn of the space age, such communications have relied on radio waves, just a small part of the electromagnetic spectrum. But scientists hope to soon expand their scope to another part of the spectrum. Its goal is to add lasers to our cosmic communication tools.
The main mission of the spacecraft Psyche is to explore a 232-kilometer-long, potato-shaped asteroid with an orbit approximately three times farther from the Sun than that of the Earth. One of the main theories maintains that the target asteroid, also called Psycheis the metallic core of a possible ancient planet that lost its rocky surface after constant collisions in the asteroid belt between Mars and Jupiter.
If so, exploring its unique mix of iron, nickel and rock may be the closest we get to investigating the Earth's metallic core.
It will take six years for the spacecraft to arrive and find out if measurements of the asteroid suggesting a metallic surface are correct. If so, we could find ourselves with a more extraterrestrial object than the writers of pulp of the 1940s and 1950s, with metallic ejecta frozen into strange shapes due to encounters with other asteroids.
But space communications researchers will begin to see results much sooner. The Deep Space Optical Communications (DSOC) test will be the first demonstration of laser or optical communication beyond the Moon, and could facilitate astronauts' return to the Moon and take the next big leap: a Mars. It also represents a key step in opening a new era in space communications.
If this and other tests work as expected, the lasers will provide a needed boost to the bandwidth limits facing the main off-planet communications system, called the Deep Space Network (DSN). ). DSN's three radio antenna sites, each dominated by a 70-meter satellite dish and located 120 degrees apart in Spain, Australia and the California desert, are facing a massive traffic jam. proportions. Today, the demands of dozens of space missions, from the James Webb Telescope to small commercial satellites (which pay for the service), must compete for network time.
“There may be conflicting requests between multiple missions,” says Mike Levesque, DSN project manager at NASA's Space Communications and Navigation (SCaN) office. “20% of requests are not met today. The problem will only get worse over time. It will be 40% in 2030.”
And in the near future, another 40 space missions will be launched, each of which will require time from the communications network. More importantly, some of those missions will be manned, with instruments transmitting high-definition video and metabolic readings of astronauts as they work on the Moon, building laboratories and shelters. They won't want to be told they have to wait for a commercial CubeSat, the minisatellites that transmit various types of scientific data and provide Internet connectivity, and which have proliferated in low-Earth orbit.
“Delays may be acceptable for science, but for human missions we need all hands on deck,” says Jason Mitchell, program executive at SCaN. “As we see what human astronauts want when we go to the Moon and plan to go to Mars, scientific instruments will also grow. “We could send terabytes of data every day.”
In the newly launched demonstration test, researchers aim to take advantage of the greater information-carrying capacity of laser light over radio waves. Optical wavelengths in the near-infrared of the electromagnetic spectrum are so small—measured in nanometers—and the frequencies so high that they can contain much more information in the same space, enabling data transmission rates 10 to 100 times faster. to those on the radio.
“That's why optics are such a good option,” says Mitchell. “The data speeds are very high.”
For similar capabilities, laser systems can also be smaller than radio ones, so they require less power, another important factor when spacecraft travel a few hundred million kilometers from home.
For the past decade, NASA has been testing the new technology in different environments, from low Earth orbit to the Moon. The instrument on board Psyche will make possible the first test in deep space, an important milestone since optical communication has drawbacks. Because the laser beam is narrow, it must be aimed at receivers on Earth with great precision, a challenge that increases with distance.
Abhijit Biswas, a DSOC project technologist at NASA's Jet Propulsion Laboratory who built the instrument, compares the difficulty to trying to hit a moving dime from a mile away. Even a shake could interfere: to keep the transceiver stable in PsycheJPL installed special struts and actuators to isolate it from vibrations from the 81-foot (about 25 meters) long spacecraft.
Other potential problems are clouds on Earth, which can block the optical beam, and significant weakening of the signal as distance increases and the beam disperses. This limits its use at distances beyond Mars, at least with current technology. Therefore, the test will only be carried out during the first two years of the mission, before the spacecraft travels further, to the asteroid itself.
For these reasons, as well as the fact that no terrestrial network of optical receivers exists today, no one predicts a time when laser communication will replace radio waves. But I could add a new channel. “Future operations will be designed for diversity,” says Biswas.
During tests on board Psyche, a five-kilowatt transmitter on Table Mountain in Southern California, will send a low-speed communications packet — nothing exotic, mostly random patterns, Biswas explains — to a laser transceiver attached to the 8.6-inch telescope. 22 centimeters) from the spacecraft. The instrument will lock on to the beam and download the message, using a camera that counts light particles, or photons, before relaying it at high speed to the 200-inch (about 508 centimeters) Hale telescope on Mount Palomar, near San Diego, where its accuracy can be compared with the original.
Even at distances closer than Mars, the laser signal is relatively fragile. The package arriving at the Hale telescope from Psyche It will consist of only a few photons, so its decoding depends on an extremely sensitive, cryogenically cooled photon-counting detector (made of superconducting nanowires) attached to the telescope.
For Biswas, an expert in laser spectroscopy, the optical communications test is the culmination of a decade-long effort. “It's very exciting,” he says. “There are many things we are doing for the first time.”
Although laser communication, such as multi-passenger lanes on highways, may not prevent future traffic jams on the Deep Space Network, it could help some messages avoid traffic jams in space.
Article translated by Debbie Ponchner.
This article originally appeared in Knowable in Spanisha nonprofit publication dedicated to making scientific knowledge available to everyone.
You can follow SUBJECT in Facebook, x and instagramor sign up here to receive our weekly newsletter.
#Fast #downloads #NASA #turning #lasers #nextgeneration #space #communications