LLNL delivers compact dual-band telescope for launch this summer aboard NASA satellite

Lawrence Livermore National Laboratory’s (LLNL) space hardware team has delivered a payload for NASA’s Pathfinder Technology Demonstrator-R (PTD-R) satellite. LLNL developed the optical payload, called Deep Purple, that utilizes a new design for an ultra-violet (UV) and short-wave infrared (SWIR) monolithic telescope.

The mission will demonstrate simultaneous monolithic UV and SWIR optical sensing from space for the first time via two co-boresighted, 85 mm aperture monolithic telescopes using a new compact custom electronics module and a novel, lightweight, carbon-composite optical housing and radiator. It will demonstrate new possibilities for scientific observations and real-time space domain awareness.

The satellite is scheduled to launch this summer aboard SpaceX’s Transporter-11 mission from Vandenberg Space Force Base in California. Rideshare provider SEOPS has handled the integration and mission services for the spacecraft.

Designed, developed, qualified and delivered in roughly one year for less than $1 million, the Deep Purple telescope also will observe UV and short-wave infrared light from high-UV stars and the galactic bulge.

LLNL’s monolithic optics are a novel line of compact Cassegrain telescopes constructed out of a single piece of fused silica. This design allows for a very compact, shelf-stable and resilient space telescope that can endure the harsh environments of a rocket launch and outer space.

“The optical package also is highly configurable, which gives us the ability to mix and match different sensors and optics within the same infrastructure to meet a variety of mission needs using a standardized small-satellite bus,” said Jordan Smilo, the LLNL Deep Purple principal investigator and space hardware lead mechanical engineer.

“Deep Purple serves as an example of how the Lab’s Space Program combines the R&D nature of LLNL with the deployment of innovative technology and its national-security mission at heart. Each satellite provides an opportunity for development and flight heritage for the nation’s increasing need for responsive payloads.”

Deep Purple’s dual optical module and electronics are contained in a 25 centimeter x 15 centimeter x 10 centimeter package.

“We believe Deep Purple will be the smallest space telescope providing both SWIR and UV imaging in space,” said John Ganino, associate program leader for space hardware at the Laboratory and system engineer lead for Deep Purple.

“This satellite is a 6U-sized space vehicle [the volume of six 10-centimeter CubeSats], so the size and mass allowed for Deep Purple is very strict. The Deep Purple payload couldn’t weigh more than 5 kilograms (about 11 pounds) maximum. We also had the added challenge of incorporating our own electronics control module within the same volume,” Smilo said.

To make the payload small and lightweight enough to meet these requirements, the team redesigned the electronics module to exactly fit within the available space adjacent to the optics.

“We also traded the heavier invar material, a nickel-iron alloy, that’s typically used for optical housings for a novel, lightweight, carbon-fiber-nano-tube-composite housing. This made a huge difference in terms of keeping the satellite light, reducing the cost and production time while maintaining optical performance. We met the maximum mass for our entire payload with margin," Smilo said.

Once operational, Deep Purple will simultaneously observe the UV and SWIR light from high-UV stars and the Milky Way’s galactic bulge. Such simultaneous imagery gives way to observing time-domain astronomical events, such as Fast Blue Optical Transients (FBOTs), a phenomenon recently discovered and yet to be understood.

Deep Purple also will attempt to demonstrate real-time space domain awareness using these unique sensing bands. The Space Program at LLNL continues to demonstrate its leadership in developing and delivering small satellite tools and capabilities.

“Deep Purple may be small — not much bigger than a loaf of bread — but the information it will reveal for the first time could make a huge impact on space-domain awareness. The team’s ability to deliver such an incredible tool in such a short amount of time, while meeting NASA’s rigorous requirements is another impressive achievement for the Lab’s space program,” said Ben Bahney, program leader for the space program at Lawrence Livermore. “Our list of achievements continues to grow. It’s an exciting time.”

NASA’s Small Spacecraft Technology program, based at NASA’s Ames Research Center in California’s Silicon Valley and within the agency’s Space Technology Mission Directorate in Washington, funds and manages the PTD-R project.