Scheduled for launch in late 2027, NEO Surveyor will be stationed a million miles away at the L1 Lagrange point between Earth and the Sun. Its position, along with a large sunshade to block sunlight, will allow the spacecraft to track near-Earth objects approaching from the direction of the Sun - a challenging area for traditional observatories to monitor. The mission may also provide new insights into Earth Trojans, asteroids that share our planet's orbit and are typically difficult to observe from Earth or its orbit.

The NEO Surveyor spacecraft will utilize advanced infrared detectors capable of observing near-Earth objects regardless of their reflectivity. By detecting the infrared radiation these objects emit as they are warmed by the Sun, the telescope will identify and measure asteroids and comets, even those that are dark and do not reflect much visible light. This capability will enhance the accuracy of detecting both small reflective and large dark objects, a task that visible-light telescopes struggle to perform.

"NEO Surveyor is optimized to help us to do one specific thing: enable humanity to find the most hazardous asteroids and comets far enough in advance so we can do something about them," said Amy Mainzer, survey director for NEO Surveyor and a professor at the University of California, Los Angeles. "We aim to build a spacecraft that can find, track, and characterize the objects with the greatest chance of hitting Earth. In the process, we will learn a lot about their origins and evolution."

Progress in Assembly
The spacecraft's primary instrument, its telescope, is currently under assembly. This telescope, similar in size to a washer-and-dryer set, features a blocky aluminum structure known as the optical bench, built in a JPL clean room. The three-mirror anastigmat design will focus infrared light with minimal optical aberrations, enhancing its ability to detect near-Earth objects.

"We have been carefully managing the fabrication of the spacecraft's telescope mirrors, all of which were received in the JPL clean room by July," said Brian Monacelli, principal optical engineer at JPL. "Its mirrors were shaped and polished from solid aluminum using a diamond-turning machine. Each exceeds the mission's performance requirements."

After inspecting the mirrors for any debris or damage, JPL's team attached them to the telescope's optical bench in August. The next steps include performance measurement and alignment of the mirrors.

The telescope's infrared detectors, made of mercury-cadmium-telluride, are akin to those used in the now-retired NEOWISE mission. These detectors have the advantage of not requiring cryogenic coolers or cryogens, which can limit spacecraft lifespan. NEO Surveyor will maintain low temperatures through its sunshade and its orbit beyond the Moon, minimizing heat from Earth.

The telescope will be installed within the spacecraft's instrument enclosure, currently under construction in JPL's historic High Bay 1 clean room. The enclosure, made of a dark composite material to allow heat dissipation, will help keep the telescope cool and prevent internal heat from interfering with observations.

Once completed in the coming weeks, the enclosure will undergo rigorous testing to ensure it can withstand the demands of space. It will then be mounted on the sunshade, atop the spacecraft's electronic systems.

"The entire team has been working hard for a long time to get to this point, and we are excited to see the hardware coming together with contributions from our institutional and industrial collaborators from across the country," said Tom Hoffman, NEO Surveyor's project manager at JPL. "From the panels and cables for the instrument enclosure to the detectors and mirrors for the telescope - as well as components to build the spacecraft - hardware is being fabricated, delivered, and assembled to build this incredible observatory."

Related Links
NEO Surveyor
Asteroid and Comet Mission News, Science and Technology