NASA launches Psyche, a mission to explore a metallic asteroid
Is the asteroid Psyche really a piece of metal? Is the object, which is almost as wide as Massachusetts, the core of a baby planet whose rocky outer layers were blown away in a cataclysmic collision in the early days of the solar system?
At this point, all astronomers can say is: maybe yes, maybe no.
NASA launched a spacecraft, also named Psyche, on Friday morning to travel to the asteroid belt between Mars and Jupiter to find out.
“We’re really going to see some kind of new object, which means many of our ideas will turn out to be wrong,” said Lindy Elkins-Tanton, a professor of Earth and space exploration at Arizona State University and the mission’s principal investigator.
That she was wrong, she added, “is, I think, the most exciting thing in science.”
That journey in search of answers began Friday at 10:19 a.m. Eastern Time. Falcon Heavy, SpaceX’s largest operational rocket, lifted off from the Kennedy Space Center in Florida, sending the massive spacecraft into space.
Friday’s flight overcame early, unfavorable weather forecasts for a seemingly flawless flight. Just over an hour after launch, the Psyche spacecraft detached from the Falcon Heavy rocket’s upper stage. NASA’s video stream showed the vehicle sailing into the darkness behind Earth and taking off on an excursion that will last about six years and cover billions of miles.
About five minutes later, mission managers in the control room of NASA’s Jet Propulsion Laboratory facility in California applauded as they received an initial signal from the spacecraft.
The asteroid called Psyche has long been a curious mystery. Spotted in 1852 by Annibale de Gasparis, an Italian astronomer, it was named after the Greek goddess of the soul, and was only the 16th asteroid discovered. In the first observations, it was, like the other asteroids, a star-like point of light orbiting the sun, and not much more.
Beginning in the 1960s, astronomers discovered in telescopic observations that Psyche’s color was similar to iron meteorites that have fallen to Earth, says Jim Bell, a professor of Earth and space exploration also at Arizona State University, who will lead research on the asteroid with the spacecraft’s camera instrument. Astronomers bounced radar pulses off Psyche, and the reflections returned to Earth were brighter than those from other small objects in the asteroid belt.
“It became quite clear that there is a part of the surface that is very radar reflective,” said Dr. Bell. “And the easiest way to do that is with metal fragments.”
And when scientists saw Psyche passing relatively close to larger worlds, its trajectory was deflected in a way that suggested something very massive, and potentially much denser than rock, was there.
Most rocks, such as granite, have a density of two to three grams per cubic centimeter. Water, whether liquid or ice, is approximately one gram per cubic centimeter. Metals such as iron are much denser, between six and nine grams per cubic centimeter.
“Some of those early estimates were like, wow, this is really unusual,” said Dr. Bell.
Psyche turned out to be almost pure metal. Earth’s core is made of iron and nickel, and Psyche’s measurements led to the idea that this could be the remnant of a similar core that belonged to a baby planet. Such worlds are known as planetesimals, where temperatures are so high that denser metals melt and fall toward the center.
It’s impossible to explore the core of a planet like Earth, 2,000 miles below the surface, but a visit to Psyche could reveal more information about what lies at the center of our planet.
Or that hypothesis could be completely wrong.
“Psyche can be something completely different than that,” said Dr. Elkins-Tanton. “I would love to be completely surprised.”
More recent measurements have led to lower estimates of the asteroid’s density, just under four grams per cubic centimeter: still denser than rock and ice, but not as dense as metal. That suggests that Psyche is made of metal and something else: maybe stone, maybe empty space.
“My best guess is that it’s more than half metal, based on the data we have,” said Dr. Elkins-Tanton.
If Psyche turns out to be full of valuable metals, it’s not too far off for anyone to mine with current technologies. Dr. Elkins-Tanton notes that even at its closest point, Psyche is about 150 million miles from Earth, which is about five times as far away as Earth is from Mars on the two planets. closest possible approximation.
The Psyche mission was supposed to start a year ago. The spacecraft had already been shipped to the Kennedy Space Center. But there were problems testing the navigation software that would guide the spacecraft through the solar system. These arose from incompatibilities between the flight software and the programs used to control it. Engineers ran out of time to fix the problems before the launch window closed.
A independent assessment of the missed launch, commissioned by NASA, concluded that leadership changes, communication failures, heavy workloads and the Covid-19 pandemic contributed to “an environment in which missions like Psyche did not receive the attention needed to address staffing levels and perceived staffing issues faced they were confronted.”
The project got back on track for 2023 by hiring new mission staff, minimizing remote work and implementing other recommendations from the review.
There were more bumps on the way to the launch pad. Psyche was scheduled to lift off on October 5, but the launch was postponed again when tests showed that thrusters used to orient the spacecraft during flight and which fired cold nitrogen gas produced higher temperatures than expected. NASA officials said they resolved the problem by planning to spin the thrusters lower energy levels to prevent them from overheating in the room.
Once launched, the Psyche spacecraft will head towards Mars, swinging past the red planet in May 2026 and using its gravity as a catapult towards the asteroid Psyche, arriving in August 2029 after a journey of 2.0 billion miles.
During his journey, Psyche will exchange laser messages with Earth as part of called an experiment Optical communications in deep space. Current spacecraft communicate using radio waves, but switching to lasers could increase the bandwidth of transmissions in deep space by up to 100 times. The laser experiment will provide the first demonstration of this new technology at distances far beyond the moon.
When it reaches the asteroid, the spacecraft will spend at least 26 months in orbit studying Psyche with a variety of instruments.
The mission’s cameras, known as multispectral imagers, will provide the first close-up view of Psyche, revealing surface features that cannot be seen from Earth. A magnetometer aboard the spacecraft will look for signs of an ancient magnetic field, perhaps similar to the one driven by Earth’s core, that may be imprinted in the asteroid’s terrain.
And a gamma-ray spectrometer will detect high-energy gamma rays and neutrons that are formed when cosmic rays collide with the asteroid’s surface. These particles contain information about the composition and distribution of metal and rock in Psyche’s alien landscape.
Finally, the spacecraft’s radio antenna will be used to map the asteroid’s gravitational field by measuring small shifts in the frequency of the Doppler signal shift, increasing as it moves toward Earth, and decreasing as it moves away. The experiment can detect differences in density within the asteroid, which could shed light on its origins.
“No instrument on its own will tell us whether Psyche is a nucleus,” Ben Weiss, the mission’s deputy principal investigator, said in a statement. Newsletter on Thursday. “It’s the combined data from all these different instruments.”
For more than 170 years, Psyche has been a small bright spot in the sky. Telescopes have revealed tantalizing glimpses of its size and features, but the nature of this unique world is otherwise a mystery. The Psyche spacecraft is now on its way to image this asteroid for the first time and solve the mystery of its origin.