On Dec. 4, the cameras of NASA’s Psyche spacecraft took their first images 26 million kilometers away from Earth. This milestone, called “first light,” was one of many the agency needed to complete on its way to its destination, a metallic asteroid called 16 Psyche. The spacecraft is set to reach this asteroid in the main asteroid belt between Mars and Jupiter in 2029.
Psyche was launched on Oct. 13 atop a SpaceX Falcon Heavy rocket from Launch Complex 39A at the Kenedy Space Center in Florida. A few hours after launch, the spacecraft entered an initial checkout phase that is set to last about 100 days, during which teams will test the spacecraft’s instruments and systems to verify they are working as planned. Testing the spacecraft’s cameras was the latest step in this phase to be completed.
Psyche’s “first light”
The first image from Psyche shows stars in the constellation Pisces, which the spacecraft’s Multispectral Imager instrument happened to be pointing at when it was first turned on. Each of the instrument’s two identical cameras took one image, both of which were stitched together to create one picture.
“These initial images are only a curtain-opener,” said Psyche imager instrument lead Jim Bell of Arizona State University. “For the team that designed and operates this sophisticated instrument, first light is a thrill. We start checking out the cameras with star images like these, then in 2026 we’ll take test images of Mars during the spacecraft’s flyby. And finally, in 2029, we’ll get our most exciting images yet – of our target asteroid Psyche. We look forward to sharing all of these visuals with the public.”
The team captured 68 images to test and calibrate the instrument and its filters. These filters allow scientists to observe 16 Psyche in different wavelengths of light and analyze the composition of the asteroid’s surface. Additionally, they will use the cameras to study Psyche’s geology and history by creating a 3D map of the asteroid.
Psyche’s Multispectral Imager instrument provides scientific images and serves as a mission-critical optical navigation instrument. The spacecraft is fitted with a pair of cameras to provide redundancy for these important tasks.
Laser communication experiment
Earlier, on Nov. 14, the teams reached another notable milestone when they tested the Deep Space Optical Communications (DSOC) experiment. This experiment is designed to demonstrate optical communications using near-infrared laser beams in deep space. Even though this technology has been used in space before, this was the first test using optical communications beyond the Moon.
To test this experiment, NASA’s Jet Propulsion Laboratory (JPL) used a laser beacon to send a signal to Psyche, which the spacecraft then locked onto and used to aim its laser at a receiving telescope on Earth. The large distance between the spacecraft and the earth – 16 million kilometers at the time of the test – meant the spacecraft had to be capable of aiming its laser extremely precisely. As an additional challenge, the teams had to compensate for the distance Psyche had traveled during the time it took the signal to traverse space.
If DSOC can demonstrate reliable optical communications, future space missions can use this technology to send and receive a lot more data per unit of time compared to radio communications. NASA hopes the DSOC can increase transmission rates by 10 to 100 times what they are currently.
“Optical communication is a boon for scientists and researchers who always want more from their space missions, and will enable human exploration of deep space,” said Dr. Jason Mitchell, director of the Advanced Communications and Navigation Technologies Division within NASA’s Space Communications and Navigation program. “More data means more discoveries.”
Even though Psyche did not use the DSOC experiment to transmit mission data, the DSOC and Psyche teams had to work closely together to make sure the test did not interfere with the spacecraft’s operations. “It was a formidable challenge, and we have a lot more work to do, but for a short time, we were able to transmit, receive, and decode some data,” said Meera Srinivasan, operations lead for DSOC at JPL.
Other tests and instruments
The DSOC experiment was not the only distance record achieved by the spacecraft. When teams fired up two of the four electric Hall-effect thrusters on Nov. 8, it was the first time this type of propulsion was used beyond lunar orbit.
Besides the Multispectral Imager instrument and the DSOC experiment, Psyche carries three more science instruments. The spacecraft’s magnetometer will measure the asteroid’s magnetic field, the Gamma-Ray and Neutron Spectrometer (GRNS) will allow scientists to determine the elemental composition of the asteroid, and finally, the X-band radio communications system will also be tasked with measuring the asteroid’s gravity field.
Shortly after Psyche’s magnetometer was powered on in late October, it detected a magnetic signal caused by a solar eruption. This not only indicated that the instrument worked and was able to detect small magnetic fields but also confirmed that the spacecraft itself did not generate magnetic fields that interfered with the observations. The latter could not be verified on Earth because of the planet’s magnetic field.
Between Nov. 6 and Nov. 27, the gamma-ray spectrometer of the GRNS was turned on to collect data for the first time since launch. “[The data] are showing us that we have a really high-performance instrument, and will allow us to refine calculations about how sensitive we’ll be when we get to Psyche,” said Psyche Gamma-Ray Spectrometer investigation lead David Lawrence of The Johns Hopkins University Applied Physics Laboratory.
Next, the teams are planning to test the neutron spectrometer of the GRNS during the week of Dec. 11.
(Lead image: Illustration of NASA’s Psyche spacecraft and asteroid 16 Psyche. Credit: NASA/JPL-Caltech/ASU)