Progress Made By Voyager 1 & 2 Spacecraft
In the late 1970s, space scientists realized that a periodic alignment of the outer planets would enable a single probe to visit Jupiter, Saturn, Uranus, and Neptune, by taking advantage of the then-new technique of gravity assists.
The idea led to Grand tour works by NASA which later turned into a massive project involving two groups and two probes with one probe from each group.
One of the group’s probes is meant for visits to Jupiter, Saturn, and Pluto, and the other is for Jupiter, Uranus, and Neptune. The spacecraft would be designed with redundant systems to ensure survival throughout the entire tour.
As at 1972, the mission was scaled back and replaced with two mariner-derived spacecraft. The first was known as the Mariner Jupiter-Saturn probes. Its mission includes only flybys of Jupiter and Saturn, but keep the Grand Tour option open. As the program progressed, the name was changed to Voyager.
The primary mission of the Voyager 1 was to explore Jupiter, Saturn, and Saturn’s moon ‘Titan’.
Voyager 2 is a space probe launched by NASA on August 20, 1977, to study the outer planets. Being part of the Voyager program, it was launched 16 days before the launch of the Voyager 1, on a trajectory that took longer to reach Jupiter and Saturn but enabled further encounters with Uranus and Neptune. It happens to be the only spacecraft to have successfully visited the mentioned planet.
Voyager 2 was to explore Jupiter and Saturn, but on a trajectory that would have the option of continuing on to Uranus and Neptune, or being redirected to Titans as a backup for Voyager 1. Upon the successful completion of Voyage 1 objectives, Voyager 2 would get a mission extension to send the probe towards Uranus and Neptune.
Meanwhile, the primary mission of the Voyager 2 ended on October 2, 1989, after the exploration of the Neptunian system, the Uranian system, the Saturnian system, and the Jovian system, in 1989, 1986, 1981, and 1979 respectively.
The probe is now in its extended mission to study the outer reaches of the Solar system and has been operating for 41 years and still counting. It had been in contact with NASA through its Deep Space Network.
Based on Voyager 2 data, it stands at a distance of 119 AU i.e. (1.78 x 1010km) (about 16.5 light-hours) from the Sun as of early 2018. Moving at a velocity of 15.341 km/s relative to the sun.
Voyager 2 is the fourth of five spacecraft to achieve the escape velocity that will allow them to leave the solar system. The probe left the heliosphere for interstellar space on November 5, 2018, and has begun to provide the first direct measurements of the density and temperature of the interstellar plasma.
DESIGN FEATURES OF VOYAGER 1 & 2
Voyager 2 was constructed by the Jet propulsion Laboratory (JPL), it included 16 hydrazine thrusters, three-axis stabilization, gyroscopes, and celestial referencing instruments (Sun sensor/Canopus Star tracker) to maintain the pointing of the high-gain antenna toward Earth.
Collectively, the instruments are part of the altitude and Articulation Control Subsystem (AACS) along with redundant units of most instruments and 8 backup thrusters. It also has 11 scientific instruments to study celestial objects as it travels through space.
COMMUNICATION METHOD OF Voyager 1 & 2 Spacecraft
Because it was built with the intent of eventual interstellar travel, Voyager 2 included a large, 3.7 m (12 ft) parabolic, high-gain antenna to transceiver data via Deep Space Network on the Earth.
Communications are conducted over the S-band which is about 13 cm wavelength and the X-band which is about 3.6 cm wavelength, providing data rates as high as 115.2 kilobits per second at the distance of Jupiter and then ever-decreasing as the distance increases.
Based on the inverse-square law. In the case of communication breakdown with the earth, the digital tape recorder (DTR) in it can record about 64 kilobytes of data for transmission at another time.
THE POWER SYSTEM OF Voyager 1 & 2 Spacecraft
Voyager 2 was equipped with 3 Multihundred-Watt radioisotope thermoelectric generators (MHW RTG). Each RTG includes 24 pressed plutonium oxide spheres, and provided enough heat to generate approximately 157 W of electrical power at launch.
Collectively, the RTGs supplied 470 watts to the spacecraft during its launching and it will ensure that the operation continues up to the year 2020.
THE PROPULSION AND CONTROL SYSTEM OF Voyager 1 & 2 Spacecraft
Since a boost with a 1,819-pound (825kg) payload energy would help the spacecraft achieve the Jupiter trajectory
The following were used to equip its propulsion system; a module made of a 2,476-pounds (1,125 kg) solid-rocket motor and eight hydrazine monopropellant rocket engines, four providing pitch and yaw attitude control and four for roll control.
The sixteen hydrazine MR-103 thrusters on the mission module provide altitude control. Four are used to execute trajectory correction maneuvers, the others in two redundant six-thruster branches, to stabilize the spacecraft on its three axes.
Only one branch of altitude control thrusters is needed at any time. The thrusters are supplied by a single 28-inch diameter spherical titanium tank. It contained 230 pounds of hydrazine at launch, providing enough fuel until the year 2034.
