Why is it so challenging to reach Pluto? Pluto is the most distant celestial body that a spacecraft has ever reached. This dwarf planet is more than 6 billion kilometers from Earth, and on July 14, 2015, only the New Horizons spacecraft was able to look at it directly. But this ship did not go into orbit around Pluto. Instead, he just looked at it once and then went on to the farthest parts of the solar system. However, why expend so many resources for a simple visit to Pluto?
The most distant of all Pluto was considered the ninth and most distant planet in the solar system for many years. Located in the remote limits of the Sun’s domain, it appeared that it would take humans generations to reach this small planet. However, the first chance to visit Pluto arrived considerably sooner than most scientists anticipated. Gary Flandro, a scientist at NASA’s JPL laboratory, realized in 1964 that between 1976 and 1978, there would be a gap of approach between the gaseous planets. If a space exploration probe were launched on those dates, it would be able to visit most of the outer planets by using a series of successive gravitational assists to take advantage of the rare planetary alignment that occurs roughly once every two centuries.
NASA then started an ambitious mission named Grand Tour, which featured two identical TOPS probes (although, in principle, they should be four). In 1976 or 1977, one of the probes would be dispatched to Jupiter, Saturn, and Pluto, while the other would visit Jupiter, Uranus, and Neptune. According to NASA’s projections, Pluto would be encountered in 1985 or 1986. NASA concluded after assessing the ambitious Grand Tour project that its cost would be too expensive, so both the Grand Tour project and the TOPS probes were terminated.
Shortly thereafter, NASA would undertake a second, more modest, and less expensive mission, from which the renowned Voyager probes would emerge. NASA kept the possibility of sending Voyager 1 to Pluto following its visit to Saturn. Initially, Voyagers were intended to follow the same trajectory as the Grand Tour mission. Voyager 1 would have passed the Pluto system in the spring of 1986 if the mission had been approved. Instead of Pluto, NASA chose to send the probe near to Titan, Saturn’s largest moon. Thus, any visit to Pluto was once again canceled.
Why were repeated trips to Pluto canceled?
The answer is straightforward: Pluto is too distant. A problem with the available technology at the time The Voyager probes lacked solar panels because they were designed to visit distant worlds, where solar radiation is very low and a solar panel would not be able to provide adequate energy. Instead, the probes were equipped with nuclear batteries that generated electricity using the heat radiation radiated by a radioactive material.
NASA determined that, due to natural wear and tear, this supply of radioactive energy could be depleted well before reaching Pluto, therefore instead of abandoning the spacecraft, it was chosen to visit Titan. No one anticipated that Voyager’s power source would continue to function after visiting Titan; it was sheer serendipity. After these expeditions, NASA determined that Pluto is a desolate, small, and distant world, necessitating that any spacecraft that visit Pluto must be extremely sophisticated and expensive.
Numerous experts believed that it would be more prudent to invest the funds in studying the huge planets and their dozens of satellites, rather than the ninth planet. There was no genuine plan to investigate Pluto during the 1980s, although there were several exciting projects. Jet Propulsion Laboratory’s Interstellar Precursor Mission (IPM) research was the most intriguing of these (JPL). The IPM project sought to quickly deploy a huge probe to the heliopause, the edge of the solar system where the solar wind gives way to the interstellar medium.
The probe would weigh approximately 90 tons. This is the heaviest exploration probe in history and would require more than five Space Shuttle trips to assemble into Earth orbit. This spaceship would feature a nuclear reactor and an electric propulsion system (NEP) with ion thrusters.
What was IPM’s relationship to Pluto?
This craft had to carry a probe to explore the ninth planet as it passed through its neighborhood. This Jupiter orbiter would be comparable to the Galileo probe. In the first decade of the twenty-first century, it would employ a propellant stage, or rocket, to slow its velocity and enter orbit around Pluto. As you might expect, this never saw the light of day because, once again, the expense of such a project would be prohibitively expensive.
Arouse the interest of curiosity
The meeting between Voyager 2 and Neptune in 1989 rekindled interest in a mission to Pluto, as it was the last planet to be explored. Moreover, Triton, the biggest moon of Neptune, was a sophisticated globe with an atmosphere, polar ice caps, and nitrogen geysers. Observations from Earth showed that Triton and Pluto shared a common origin in the Kuiper belt and, thus, must be quite similar, especially after Pluto’s tenuous atmosphere was discovered in 1988.
In addition, the first moon of Pluto, Charon, was discovered in 1978, so a probe could potentially investigate two planets for the price of one. A mission to Pluto has again risen to the top of the scientific community’s list of objectives. The Pluto 350 mission idea was one of the first. The weight of the spacecraft, including the radioisotope generator (RTG) used to provide electricity, should not exceed 350 kilograms.
Two months after Voyager 2’s rendezvous with Neptune, Pluto 350 was born. It intended to feature only four instruments: a camera, an ultraviolet spectrometer for studying the atmosphere, a radio experiment to watch the atmosphere primarily, and a plasma analysis equipment. Alan Stern, a planetary scientist and one of the mission’s planners, played a pivotal role in the history of Pluto’s exploration. Scientists believed that the atmosphere of the dwarf planet might freeze as the planet traveled away from the 1987 equinox, thus the launch should occur as soon as feasible.
As with the other Pluto-bound spacecraft ideas, the Pluto 350 mission was designed to fly by Jupiter in order to perform a gravity assistance maneuver, so reducing the flight duration by two or three years, depending on the launch window. The most powerful American launcher at the time, the Titan III or Titan IV, was required for the mission’s launch in order to set the ship on a direct trajectory to the gas giant. Nevertheless, this condition increased the mission’s cost. NASA rejected the Pluto 350 mission on the grounds that it was too basic.
Due to the fact that many scientists and engineers stated that launching a 350 kilogram probe into the outer solar system was irresponsible and lacked any prospect of success, given that earlier Voyagers had a launch mass of approximately 800 kg. In other words, NASA favored a difficult and expensive mission with a certainty of success to a simple one with a chance of failure. Missions that were never completed.
In an era with limited funds, NASA prioritized simple flyby missions. Robert Staehle of JPL went farther in 1992 by announcing the Pluto Fast Flyby (PFF) mission. A small mission compared to everything that had been accomplished to that point. If Pluto 350 was a little probe in the past, PFF would be minuscule, as its mass would be less than 150 kg. Few anticipated that such a probe could be constructed a few years ago, but due to NASA’s budget limitations, these new low-cost missions are now almost the only choice.
Years later, NASA rejected the Pluto Fast Flyby mission idea in favor of the Pluto Express mission. Since David Jewitt and Jane Luu found the first object in the Kuiper belt in 1992, it has become increasingly evident that Pluto is a member of this new family of trans-Neptunian objects and not a planet like the others. This is why the mission will be called Pluto Kuiper Express (PKE). PKE would weigh 175 kilograms compared to Pluto Fast Flyby’s 140 kilograms and carry 9 kilograms of scientific gear, although having an identical design. Pluto Fast Flyby and Pluto Kuiper Express were ultimately canceled owing to budget cuts.
However, a trip to Pluto remained a scientific priority as the launch window from 2001 to 2006 rapidly closed, leaving no other option. In desperation, NASA held a public contest in 2000 to select a mission to Pluto. This method had worked exceptionally well previous Discovery missions, but never before had such an expensive mission been attempted. Since the Pluto mission requires a more expensive mission than a Discovery mission but a less expensive mission than a Flagship mission, NASA created the New Frontiers category for this sort of probe in 2002. Thus, on February 5, 2001, the New Horizons was the winning proposal.
Initially, it would transport four scientific apparatus, including:
- PERSI (consisting of the Alice ultraviolet spectrometer;
- The MVIC color camera;
- The LEISA infrared spectrometer;
- REX (a radio experiment)
- LORRI (a black and white telescopic camera)
- PAM (for the study of particles) (for the study of particles)
To lower the mass and cost of the probe, the triangular structure’s corners were “trimmed” and the antenna’s diameter was reduced from 3 to 2.1 meters. The final vehicle mass was 478 kg. In 2014, the overall cost of the mission would amount to $646 million.
New Horizons approached Jupiter during February and March 2007 to acquire a speed differential of approximately 4,023 meters per second (14,482 kilometers per hour). In July 2013, the probe transmitted the first photographs in which Pluto and Charon, its largest satellite, can be recognized as distinct bodies. As New Horizons approached Pluto, the resolution of the photos transmitted back increased. The New Horizons spacecraft flew 12,500 kilometers from Pluto’s surface at a relative speed of 49,600 kilometers per hour on July 14, 2015, capturing the most detailed photographs ever of what was once the ninth planet in the solar system.
In addition to taking photographs of Pluto, the probe transmitted a great amount of data that has helped uncover all of this celestial body’s mysteries; as a result, we now know that Pluto is a large ice-covered sphere with recent geological activity that may contain water. After its flyby of Pluto, the New Horizons probe resumed its voyage to the farthest regions of the solar system; no other mission has yet reached this remote world. Do you believe we will return to Pluto?
