In case you missed it, NASA recently beamed this “Cat video from Space” on December 11.
The video was sent using laser optics from the NASA Psyche spacecraft as part of the Deep Space Optical Communications (DSOC) technology experiment. DSOC is an experiment to demonstrate laser-based communications from deep space to augment traditional microwave radio based communications, since lasers can provide much higher data rates at much lower size, weight and power for the onboard equipment.
During the event, the Psyche spacecraft was 31 million km away. It took 101 seconds for light to travel from the spacecraft to the receiving station in Palomar, CA. The data rate achieved in the experiment was a blazing 267 Mbps! www.jpl.nasa.gov/...
The 15-second ultra-HD video features Taters the cat, who lives with Joby Harris, a visual strategist for the NASA laboratory’s design team, which uses art to communicate missions to the public. In the video, 3-year old Taters is shown chasing a red laser (video of cat chasing laser beamed down using a laser, got it!). The cat video also has a graphical overlay of technical information about DSOC, the Psyche spacecraft, info about Taters including its heart rate and DSOC data rates achievable at various distances.
The video was created and stored on the spacecraft before launch which took place on Oct 13.
Psyche and DSOC
DSOC is a technology demonstration piggybacked on the Psyche spacecraft, which was launched on Oct 13, 2023, to study the metallic asteroid 16 Psyche in 2029.
See the graphic below for an overview of DSOC and its parameters.
A 4W infrared laser onboard the spacecraft is used to modulate data using light at 1.55 µm wavelength. A 200-inch telescope, superconducting detectors and sophisticated signal processing equipment is used at the Palomar Observatory in California to recover data from the faint signal and to forward it to JPL. A lower rate uplink is transmitted from JPL’s research station at Table Mountain, NE of JPL, to help the optical equipment in the spacecraft point its laser with high precision at the receiving station.
Downlink data rates decrease with distance, falling to 1 Mbps at 2.5 AU (1 AU = 150 million km = mean Earth-Sun distance); rates are higher at night than during daytime (one can guess why).
The spacecraft telescope assembly has a point-ahead mirror, which is used for fine-pointing of the laser and for "pointing ahead" since the receiver can move quite a distance after the photons leave the quarterback laser transmitter. E.g., in the 8.3 minutes it takes light to travel 1 AU, earth moves about 15,000 km along its orbit.
The Hale Telescope and the Palomar Observatory
The DSOC laser beam was received using the 200-inch Hale Telescope at the Palomar Observatory located in San Diego County, CA. The astronomical research center is owned and operated by Caltech.
The 200-inch Hale Telescope (f/3.3) was the world's largest effective telescope for 45 years (1948-1993). The revolutionary telescope was considered the “moon shot” of the 1930s and 40s.
You can read more about the telescope at https://sites.astro.caltech.edu/paloma and take a fascinating virtual tour of the facility at sites.astro.caltech.edu/...
Epilogue
Why a cat video? Obviously, cats have a special relationship with humankind and with the Internet today. Also, cats and cat images have been used in space missions and TV test broadcasts before. The cat chasing a laser beam was a nice touch. It certainly got everyone’s attention.
More importantly, this paves the way for laser based communications from deep space directly to earth, whose higher data rates will be beneficial for future deep space missions.
Well done, NASA and NASA engineers 🐱🐱🐱