Launching a prototype telescope to the International Space Station

A prototype telescope designed and built by Lawrence Livermore National Laboratory (LLNL) researchers has been launched from Cape Canaveral, Florida, to the International Space Station (ISS).

The telescope, known as the Stellar Temporal Superimaging Payload (SOHIP), uses patented LLNL monolithic optics technology on an observing and measuring deflector instrument. atmospheric gravitational waves and disorder.

The SOHIP instrument was launched on Tuesday, and will be installed as part of the Department of Defense’s Space Test Program — Houston 9 platform once it is aboard the International Space Station.

Livermore’s multidisciplinary team produced the SOHIP instrument and met strict NASA safety requirements for inclusion on NASA’s International Space Station, a laboratory first. Also, SOHIP was delivered on time and on a modest budget of only $1 million.

“Our goal was to design, develop and deliver a pair of compact, rugged, single-module telescopes that take advantage of patented monolith technology and off-the-shelf parts that require little or zero-orbit testing for inclusion on the International Space Station,” said Pitt. Supsinskas, chief space technologist for the LLNL Space Science and Security Program. And we achieved this goal.

Hypersonic vehicles – aircraft or missiles – travel at five times the speed of sound below altitudes of 90 kilometers (km) / 56 miles – operating in an extreme, unpredictable environment at the top atmospheres, which can affect flight performance. Atmospheric gravitational waves – oscillations of air that transfer energy and momentum from the lower atmosphere to the upper atmosphere as they propagate vertically and horizontally – create turbulence such as ocean waves crash on the beach.

“if it was boundary layer on a hypersonic vehicle that experiences atmospheric turbulence along its flight path, Aerodynamics The heat on the vehicle would increase dramatically, affecting vehicle control, said Matthew Horsley, LLNL physicist and SOHIP principal investigator. Vehicle design, reduce costs and improve overall performance for hypersonic flight. ”

understand the atmosphere

One well-known data point about the upper atmosphere is the refractive index of air, which is measured by temperature and density. Another measurable aspect of conditions in Earth’s atmosphere is how light passes through it – bending of the rays occurs, sensitive to the average refractive index. The turbulence also affects the light, causing it to shimmer. This is why the stars shine so brightly in the night sky.

The SOHIP development team decided to exploit these phenomena to sense changes in atmospheric temperature and density and use fluctuations in air refraction to detect turbulence.

“By carefully measuring the bending of the rays and the luminescence, we can estimate the properties of the atmosphere that created these effects,” Horsley said.

SOHIP uses two monocular telescopes, which are connected to a gimbal assembly. The pivot allows the telescopes cameras to aim at two bright stars On the heels of the International Space Station. “The real challenge is that every camera needs to shoot a star at frame rates in excess of 1,000 frames per second,” said Lance Sims, SOHIP’s Flight Programs and Operations Leader. Achieving these higher frame rates requires a small sub-matrix readout, or “window,” from the camera’s sensor.

“Tracking the star’s apparent motion and keeping it within that window using the axis would introduce unacceptable vibrations. Therefore, we developed specialized firmware and algorithms to keep the axis constant and have the window follow the star through the sensor instead.”

The high frame rate facilitates the quantification of observation flash, while relativistic measurements between the two telescopes allow platform motion and vibration to be rejected. The first telescope has a narrow field of view and once installed on the International Space Station, it will spot a single bright star, the “flag” star, as its line of sight passes through Earth’s atmosphere.

The second telescope images the second star, the “reference” star with line of sight above the atmosphere. SOHIP will measure the relative angular separation of the flag star relative to the reference star to determine the refractive index. Flag star blink will also be measured by recording the flag star’s intensity at rates over 1,000 frames per second.

Not much bigger than a shoebox

On board the International Space Station, SOHIP weighs 30 pounds and isn’t much bigger than a shoebox. This tiny beam will reveal new insights into the average atmospheric temperature, pressure, density and strength of turbulence at unprecedented height and resolution.

“SOHIP may offer opportunities to improve hypersonic vehicle design and flight performance,” said David Patrick, chief engineer. “The data SOHIP captures about gravitational waves from multiple angles and star settings will inform future missions, allowing us to develop algorithms to predict upper atmosphere conditions.” . for the SOHIP project.

A follow-up Laboratory-Directed Research and Development (LDRD) feasibility study titled “Remote Monitoring of Gravitational Waves with Multiple Satellite Data Sets” investigates whether SOHIP data can be combined with data from three other instruments on the International Space Station to measure atmospheric gravitational waves disturbing the atmosphere upper.

“We are investigating whether the different properties of the atmosphere measured by the four International Space Station instruments can be combined to observe gravitational waves with horizontal resolution of up to 10 km throughout the upper atmosphere. Characterization of gravitational waves will allow us to better understand upper atmosphere The constraining models of the atmospheric cycle, says Dana McGuffin, a postdoctoral researcher in the Department of Physics and Life Sciences in the Atmospheric, Earth, and Energy Laboratory in the Physical and Life Sciences.

“We set out to develop, manufacture, deliver and demonstrate an economical and scalable in-orbit prototype capable of observing atmospheric gravitational waves and high-altitude turbulence from ground level to altitudes of up to 70 kilometres,” said John Janino, LLNL. Associate Program Leader for Space Instruments.

“The fact that this team can do something so technically complex on a limited budget and tight schedule is testament to their experience, collaborative spirit, and commitment to excellence,” said Ben Bahni, program lead for the Laboratory’s Aerospace Science and Security Laboratory.