After five years of space journey NASA space probe Juno is getting close to its mission’s objective: Jupiter.
Yesterday NASA used Deep Space Network 70 m dishes to send four commands from Goldstone, Colorado for Juno space probe which is 860.81 million kilometers from Earth and is getting close to Jupiter. Commands were sent at 19:15 GMT and were received by Juno after 48 minutes. Most crucial “ji4040” command switched Juno to autopilot which will perform maneuver of insertion into Jupiter’s orbit. To reach correct orbit Juno will start its propulsion for 35 minutes to reduce speed and enter correct orbit.
Juno space probe was developed by NASA under New Frontiers program and launched on August 5, 2011. It was designed by Lockheed Martin; It is powered with solar panels (as first in history space probe sent to Jupiter) installed symmetrically around fuselage. Length of single panel is 8.9 m (width is 2.7 m) what makes span of the probe at almost 18 m. Due the huge radiation level, solar panels are providing only 420 W of power for scientific payload and avionics. During passing through eclipse out of day zone close to Earth, Juno was powered by two Lithium batteries with capacity of 55 Ah each. Lockheed Martin and various institutions cooperating in creating Juno, were forced to design scientific instruments and avionics on highest technical level combining low power consumption with radiation resistance. Probe was equipped in thermal protection system to keep electronics in stable conditions inside titanium case with dimensions of 0.8 m × 0.8 m × 0.6 m and with sides thick for10 mm. Communication equipment is based on Ka and X band transponders provided by Jet Propulsion Laboratory (X band with 2.5 m dish) and Agenzia Spaziale Italiana (Ka band with two smaller dishes). Communication with Juno is performed via Deep Space Network (70 m dish) communication system. Onboard scientific equipment covers two magnetometers (by NASA Goddard Space Flight Center); Advanced Stellar Compass (ASC by Danmarks Tekniske Universitet) which is star tracker based on four CCD cameras. Probe is also equipped with six Microwave Radiometers, each with separate antenna for measuring layers of Jupiter atmosphere (provided by JPL), Jupiter Energetic Particle Detector Instrument (JEDI by Johns Hopkins University Applied Physics Laboratory) is based on three particles detector with mass spectrometers, Jovian Auroral Distributions Experiment (JADE by Southwest Research Institute) with three energetic particle detectors, Waves (by University of Iowa) which is dipole magnetic antenna for measuring magnetic and electric fields, Ultraviolet Imaging Spectrograph (UVS by Southwest Research Institute), Jovian Infrared Auroral Mapper (JIRAM by Istituto Nazionale di Astrofisica in Milan) which is infrared camera for imaging upper layers of Jovian atmosphere and Junocam (by Malin Space Science Systems) which is wide angle camera operating in resolution of 3 km per pixel with four optical filters (420 – 520 nm , 500 – 600 nm, 600 – 800 nm, 890 nm). Propulsion of Juno is based on single bipropellant thruster and twelve smaller thrusters. Main LEROS-1b engine (by AMPAC-ISP) uses hydrazine and nitrogen tetroxide and is able to provide 645 N of thrust. Twelve additional thrusters are utilized for attitude control and trajectory corrections.
Probe after being launched on August 5, 2011, from Cape Canaveral AFS on atop of Atlas V (551), reached heliocentric orbit and after two years started its pass around Earth. It used Earth gravity to increase own speed and started final journey to Jupiter orbit where it will stay for 11 days and 33 orbits. After this time it will burn in Jupiter’s atmosphere on 19th October 2017.