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Our deepest view of the universe is powered by photovoltaics. NASA was an early adopter of solar technology, and it remains an important element of spacecraft today.
American engineers at Bell Laboratories introduced the first photovoltaic solar cell in 1954. Four years later, the National Aeronautics and Space Administration (NASA) launched solar panels into space.
Today, solar panels power the James Webb Space Telescope, which has given the world the most detailed look at the farthest reaches of the universe to date.
NASA launched the Webb Space Telescope on Christmas Day 2021. The telescope consumes less power than you might think. In fact, only one kilowatt, equivalent to the energy used in the microwave, is needed to power the device. NASA said Webb will remain energy efficient more than 1 million miles from Earth, reliably powered by photovoltaics.
In the main observatory of the ship there is a deployable solar panel of 6 meters. It will act as the telescopes "power plant," powering all of its scientific instruments, communications, and propulsion systems. The system is sized at 2 kW to account for degradation that will occur over time due to harsh space conditions.
The assembly is made up of five panels connected by hinges to fold onto the launch vehicle, the Ariane 5 rocket. The telescopes onboard battery was designed to last only a few hours, so deployment and activation of the assembly was considered one of the most critical first steps of the telescopes journey. Below, you can see a video of the deployment of the unfolded set.
sun in space
The James Webb Telescope isnt the only NASA project to rely on photovoltaics to power its systems. Last June, NASA astronauts Shane Kimbrough and European Space Agency (ESA) Thomas Pesquet completed their International Space Station upgrade spacewalk, installing iROSA deployable solar arrays.
The installation of the six panels has cost about 100 million dollars. The panels are expected to add more than 120 kW of capacity, which will increase the stations power generation by 20% to 30%. The solar panels that were replaced were designed for a 15-year lifespan, but had been in continuous operation since December 2000. Although they worked well, the older arrays unsurprisingly showed signs of degradation.
Last December, NASA announced that it is testing solar-powered electric propulsion systems for defense against asteroids. The Double Asteroid Redirection Test (DART) mission will use deployable solar arrays and a 6.9 kW grid ion electric propulsion system to redirect asteroids in the direction of Earth, crashing the small craft into the asteroid.
The spacecraft is designed to propel at about 250 kilometers per hour, guided by an onboard camera and autonomous navigation software, directly into the asteroids path. The DART test will make contact with the asteroid in the Didymos system, which will go into orbit in September 2022.
NASA is also using two large cross-shaped photovoltaic arrays to power its Psyche mission, which will carry a spacecraft 1.5 billion kilometers from Earth to asteroid Psyche. The mission is to explore a large metal-rich asteroid with the remotely operated spacecraft.
Psyches solar array measures 7.1 feet long and 24 feet wide on each side when fully unfolded. The two cross-shaped arrays are deployed from the spacecraft, and represent the largest solar array ever deployed by the Jet Propulsion Laboratory, NASA said. So large, in fact, that the entire spacecraft failed to unfold during testing at the Arizona State University Tempe lab. The ASU has partnered with NASA on this mission, which will look at the allegedly unusually high amount of metals in the asteroids thickest band.
On Earth, the solar array can generate about 21 kW of electricity, but far from the sun, next to Psyche, they will only produce 2 kW, about the same energy demand as a hair dryer. Despite this low amount of energy, it will be enough to power the planned three-and-a-half-year trip to the asteroid, and the two years of orbiting and observing the body.
“Even early on, when we were designing the mission in 2012, we were talking about solar electric propulsion as part of the plan. Without it, we wouldnt have the Psyche mission,” says Lindy Elkins-Tanton of Arizona State University, who leads the mission as principal investigator. “And it has become part of the character of the mission. Specialized equipment is needed to calculate trajectories and orbits with solar electric propulsion.”
Launch is scheduled for this August, and the Psyche spacecraft could make first contact with asteroid Psyche in 2026. |
