NASA to Test AstroPix Gamma-Ray Detectors on Upcoming Robotic Mission

A new type of gamma-ray sensor developed by NASA, named AstroPix, is slated for a robotic arm demonstration on the agency’s Fly Foundational Robots mission. The mission is targeted for launch in late 2027.

Gamma rays represent the highest-energy form of light and originate from events such as lightning in Earth's atmosphere, powerful solar flares, and cosmic collisions in distant galaxies. The AstroPix technology demonstration sensors are engineered to measure gamma rays with energies between 20,000 and 700,000 electron volts. This contrasts with visible light, which falls between 2 and 3 electron volts.

While current NASA missions, including the Fermi Gamma-ray Space Telescope and Neil Gehrels Swift Observatory, also observe gamma rays, existing detectors exhibit reduced sensitivity for energies ranging from 500,000 to 1 million electron volts. This specific energy range is where many powerful gamma-ray bursts are brightest and where astronomers anticipate strong glows from massive, distant active galaxies fueled by black holes. Future missions could utilize stacked AstroPix detectors to bridge this observational gap.

Each AstroPix chip contains four silicon pixel gamma-ray detectors, with each detector incorporating 1,225 pixels. These detectors, developed at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, operate similarly to cellphone camera sensors but are specifically sensitive to gamma-ray light. Dan Violette, an AstroPix team member and post-doctoral fellow at NASA's Goddard Space Flight Center, stated, "We need to thoroughly test AstroPix’s performance before we can use the sensors in future science missions."

The AstroPix Satellite Technology dEmonstration Payload (A-STEP) will be housed within the Fly Foundational Robots mission's Orbital Replacement Unit. This movable module, along with a robotic arm, is provided by Rocket Lab Robotics. Astro Digital will supply the spacecraft for the mission. The robotic arm will reposition the unit during flight to perform in-orbit operations, with the A-STEP payload collecting data following this repositioning.

Bo Naasz, senior technical lead for In-space Servicing, Assembly, and Manufacturing at NASA Headquarters, noted, "One of our major goals with Fly Foundational Robots is to demonstrate robotic changeout of payloads in orbit, enabling upgrades or improvements to satellites and space instruments." He added that the Orbital Replacement Unit, initially designed for repositioning without a payload, was found to have the necessary volume, power, and data interfaces for the AstroPix team's design.

According to NASA Breaking News, this collaboration offers a unique orbital flight opportunity for AstroPix, as many comparable technology demonstrations typically only reach near-space environments.