VOYAGER 1 IMAGING SCIENCE SUBSYSTEM FINAL DRAFT #4

Voyager 1 and the James Web Telescope have similar missions. Voyager 1’s imaging subsystem helps to search for new rings by “map the radial and azimuthal distribution of material in the ring plane”. It attains comprehensive multi-spectral imaging across all satellites, determines rotation speeds and spin axis orientations, examines Triton's surface features at resolutions below 2 km, and explores for any unidentified moons (NASA, n.d). The images of the planetary atmosphere captured by the cameras also help data analysts determine the wind velocities of each region observed (NASA, n.d).

Being launched in 1977, the Voyager 1 had the most technologically advanced imaging system at the time. However, the modern spacecraft imaging system of the James Web Telescope has improved based on the Voyager 1 imaging system and helps scientists to further study other planets with the images captured with the latest technology available.

The Imaging Science Subsystem (ISS) of Voyager 1 was used to capture valuable scientific images of the Jupiter and Saturn system allowing valuable research insights before adventuring into deep space (JetPropulsionLab, n.d.). James Webb Telescope is examining the phase of the universe with infrared vision and helping scientists to know how galaxies form over billions of years (NASA, n.d).

Voyager 1 played a crucial role in exploring the Jupiter system and paved the way for further deep space exploration around the Jovian systems. In terms of features, the system consists of two cameras, a 1500mm high-resolution narrow-angle f/8.5 camera and a 200mm lower resolution wide angle f/3 camera (SETI, n.d.). However, James Webb has better instruments that allow it to provide clearer images such as a Mid-Infrared Instrument (MIRI), Near-Infrared Spectrograph (NIRSpec) and Near- Infrared Camera (NIRCam) (NASA, n.d).

For imaging systems, Voyager 1 has two television-type cameras: low-resolution wide-angle and high-resolution narrow-angle, both mounted in front of the vidicons with 8 filters in a commendable Filter Wheel. James Webb has 2 different types of detectors: mercury-cadmium-telluride “H2RG” detector and arsenic-doped silicon detector. 

Voyager 1 employed a magnetic deflection vidicon with a 25mm diameter, utilizing a selenium sulphur target capable of retaining high-resolution images over 100 seconds. The active imaging area measures 11.14 x 11.14 mm, and each frame consists of 800 lines with 800 pixels per line. The electronic readout of one frame takes 48 seconds. Light flooding is used to remove residual images, followed by 14 erase frames to stabilize the vidicon target for the next exposure sequences (VGR ISS Calibration Report, 1978).

The “H2RG” detector is for 0.6-5 micrometres “near infrared” while the other one has 5-28 micrometres for “mid-infrared” and has about 4 million pixels and 1 million pixels (NASA, n.d.).According to NASA, n.d, the mercury-cadmium-telluride can be tuned to sense longer or shorter wavelengths by varying the ratio of mercury to cadmium. This feature can help to tailor each camera detector and obtain the peak performance over the wavelength which will be used (NASA, n.d.).

James Web Telescope has a special feature which is MIRI, it is an instrument specialising in mid-infrared detection, which operates under the coldest temperatures among all the telescope’s instruments (Space.com, n.d.). MIRI required additional cryocoolers to reach a temperature of -266 degrees, which is only 7 degrees above absolute zero, where atomic motion ceases (Space.com, n.d.).

By comparing the features of Voyager 1 and the James Webb Telescope, we can conclude that James Webb offers higher-resolution imaging and wider spectral range capabilities compared to Voyager 1's vidicon-based system. It shows that the improvement of technology has also helped us to explore space better as time passes.

First image of Jupiter by Voyager 1

Carina Nebula (high resolution) by James Web Telescope

Reference 

Ring-Moon Systems Node - Voyager 1 Narrow Angle Camera Description. (n.d.-b). https://pds-rings.seti.org/voyager/iss/inst_cat_na1.html#inst_info

Infrared Detectors Webb/NASA. (n.d.). https://webb.nasa.gov/content/about/innovations/infrared.html#:~:text=Webb%20uses%20two%20different%20types,Teledyne%20Imaging%20Sensors%20in%20California

Pultarova, T. (2022, November 8). James Webb Space Telescope’s supercold camera bounces back from glitch. Space.com. https://www.space.com/james-webb-telescope-miri-instrument-returns-science-mode

Voyager - Spacecraft - Imaging Science Subsystem (ISS). (n.d.). https://voyager.jpl.nasa.gov/mission/spacecraft/instruments/iss/

Near Infrared Camera (NIRCAM) instrument Webb/NASA. (n.d.). https://webb.nasa.gov/content/observatory/instruments/nircam.html

d

uy