The New Horizons Mission - Report Example

New Horizons From time immemorial, the exploration of the solar system beyond the earth has been one of the main endeavors of scientists. Many scientists and importantly space organizations have come up or coming up with many discoveries and are also launching missions into the interplanetary space. Speaking of missions, space organizations particularly NASA has been sending manned missions and unmanned probe missions to discover the origins and nature of the various planets in the solar system and even beyond. Among the planets, Pluto being the farthest “planet” or dwarf planet has not been explored that well by the space scientists thereby making the New Horizons mission to Pluto a path-breaking one. New Horizons is a flyby reconnaissance mission launched in 2006 to explore the Pluto system and the Kuiper Belt. With strong backing or reasoning from the scientists, this mission turned out to be the first mission under the NASA’s New Frontiers series consisting of medium-class, probe-based planetary exploration missions. Blasted off using Atlas 5 rocket from Cape Canaveral Air Force Station, Florida, the probe will travel more than three billion miles into the space reaching Pluto by 2015, with the aid of the time-saving slingshot effect which was gained from a Jupiter flyby in 2007. The flight system of the New Horizons mission is a 400 kg spacecraft, containing highly optimal subsystems as well as 7 key scientific instruments. The spacecraft is nuclear-powered using a Radioisotope Thermoelectric Generator (RTG). It was built primarily by Southwest Research Institute (SwRI) and the Johns Hopkins Applied Physics Laboratory (APL), with Alan Stern, a former NASA Associate Administrator and currently in SwRI, being the principle investigator. When the probe attains its closest approach to Pluto on July 14, 2015, coming within 10,000km of the Pluto, it will do an in-depth study and will try to accomplish number of its’ mission objectives. After its Pluto flyby, the probe will continue its journey to study the Kuiper Belt and even beyond. When the spacecraft was launched in early 2006, Pluto was still classified as a planet, but in the same year, it was reclassified as a dwarf planet by the International Astronomical Union (IAU) thereby making this mission quite crucial in developing a debate around Pluto’s status. So, as touched slightly in the above section, the report will focus on the reasons scientists proposed to convince NASA to fund and launch the New Horizons mission, the timeline of the mission, the instrument of RALPH, power source for the mission, the scientific goals, mission’s plans after flies by Pluto, and finally a personal opinion regarding the status of Pluto as a planet or not based on the findings of the mission. Reasons scientists proposed to convince NASA Interest about Pluto among the NASA scientists arose in 1990s, with NASA planning two missions, Pluto Fast Flyby and Pluto Kuiper Express. However, due to high costs, NASA cancelled both these missions. This decision of NASA was criticized by the scientific community, government officials, as well as the public, all of whom put intense pressure on NASA to renew it. Bowing to the pressure, in 2001, NASA solicited mission proposals for a flyby reconnaissance mission to Pluto and Kuiper belt (Berger). Five proposals were put forward with only two being short listed, with the New Horizon mission proposal submitted by APL being one of them and which was eventually selected. Although, NASA selected the proposal, it did not request funding from the government for the mission. However, when the Congress initiated the funding for this New Horizons mission as a budget earmark for first two years, and importantly when the scientists put forward their valid reasons for the mission, NASA got the message and requested the needed funds for the mission (Berger). The scientists at APL were able to formulate a convincing proposal with strong reasons. Before going into the technical details of the proposals, scientist provided practical reasons for exploring Pluto. Scientists are the opinion that as the Pluto goes on its 248-yearlong orbit around the sun, there are possibilities that its fragile atmosphere can freeze and eventually collapse to the surface (Berger). That is, as the already frigid Pluto becomes even colder as it travels away from the sun, scientists believe that majority of its surface will be inundated with nitrogen-based snow thereby increasing the freezing of the atmosphere and eventually collapsing it. In addition, scientists are also not aware about how much time is remaining before the atmosphere of Pluto collapses (Berger). When that happens to Pluto’s atmosphere, according to the scientists, it may not re-emerge for about 200 years (Berger). So, because of this disastrous possibility, scientists urged NASA to initiate the mission soon. The other reason put forward by the scientists was that it was not a symbolic mission; instead a lot of things could be studied and understood. As the principal investigator Alan S Stern stated, scientists wanted to go to Pluto to study about the outer solar system’s origins, to get a better understanding of the binary planets’ formation particularly the Earth-Moon system, as well as to explore for the first time an icy dwarf, not a terrestrial planet (Berger). Apart from these reasons, the APL team was able to convince NASA by highlighting the cost-effectiveness of their proposal. That is, in the proposal, APL laid strong emphasis on reducing programmatic risks, which included the cost rises and schedule delays (Stern). The other reason which was put forward by the APL team is its incorporation of a very large, 48 Gbit solid state memory (Stern). This is in big leap from the 8 Gbit memory proposed in the earlier but defunct mission of Pluto Kuiper Express. This increased memory is expected to allow the spacecraft take optimum advantage of its exploration in the Pluto system. So, although NASA was initially against sending a probe to Pluto, scientists with their valid reasons were able to convince it. Timeline of the mission New Horizons was launched successfully on January 19, 2006 at 19:00 hrs. The spacecraft got separated from the carrier rocket within an hour. The next day New Horizons probe crossed Moon’s orbit successfully showing it as the fastest spacecraft ever to leave from earth (“New Horizons Full Mission Timeline”). On April 07, it crossed Mars orbit. On January 2007, New Horizons took images of Jupiter and Io from a very long distance. By mid of February 2007, New Horizons was traveling towards Jupiter. It approached Jupiter’s orbit system, so it can use the gravitational assist to fasten its speed. New Horizons moved closer to Jupiter’s moon Europa in the next two weeks and also encountered a closest approach towards most of Jupiter’s other moons namely Ganymede, Callisto and Io (“New Horizons Full Mission Timeline”). By the month of June, New Horizons was 10 Astronomical Units away from Sun as it continues it journey towards its destination planet of Pluto. In the next few days it came very closer towards Asteroid Chiron which was 11.908 AU away from Sun (“New Horizons Full Mission Timeline”). In June itself, New Horizons crossed Saturn. In the year 2010, by end of February, it was found that New Horizons has traveled halfway to Pluto. On July same year New Horizons had traveled halfway the distance between Sun and Planet Pluto. By March 2011, it crosses the Uranus orbit (“New Horizons Full Mission Timeline”). During May the same year, it was 20 Astronomical Unit away from Sun. On November, it crossed by Asteroid Pholus. In 2014 during July end, it was traveling at a distance of 30 AU away from Sun. On August 2014, it crossed Neptune’s orbit the day before celebrating 25th anniversary of Voyager 2 which flew over Neptune and captured pictures of the ice giant (“New Horizons Full Mission Timeline”). On November 2014, New Horizons approached nearer to L5 one of Neptune Trojans. To conclude, New Horizons is estimated and expected to reach Planet Pluto on 15 July, 2015(“New Horizons Full Mission Timeline”). RALPH and power source for New Horizons New Horizons carries seven scientific instruments, namely ALICE (ultraviolet spectrometer), Ralph (combines infrared spectrometer (LEISA) and color optical imager (MVIC)), REX (radio experiment), LORRI (optical telescope), PEPSSI (plasma-sensing instrument), SWAP (plasma-sensing instrument), and finally SDC (instrument to measure dust impacts). Among these instruments, the focus is on the RALPH which is considered to be one of the core instruments of the mission, with Stern even dubbing it as the mission’s main sense of sight (“Ralph Aims to Put Pluto in Focus”). As above-mentioned, Ralph combines infrared compositional mapping spectrometer along with visible-light CCD imager having broadband and color channels backed by a powerful telescope. It weighs around just 10.5kg and requires just 7.1W peak thereby making it compact power efficient (Reuter et al.). RALPH’s primary purpose is to map the surface geology, geomorphology, and composition of the related objects. It will map based on a typical resolution of about 1 km per pixel, taking stereo as well as night-time images thereby aiding the scientists to form and refine the radii and the orbits of Pluto and Charon (Reuter et al.). Basically, it will make the maps which could show how the objects in Pluto, Charon, and Kuiper Belt might look like. Its other purpose is to map the surface temperature, which can be done by sensing the spectral features of certain gases including frozen nitrogen, water as well as carbon monoxide (“Ralph Aims to Put Pluto in Focus”). RALPH has plans to search for cloud formations and hazes in Plutos atmosphere, as well as additional satellites around Pluto. New Horizons mission is powered using a cylindrical radioisotope thermoelectric generator (RTG). Developed by the U.S. Department of Energy at the Materials and Fuels Complex, Arco in Idaho, the Plutonium-238 fuel in it is only used to power the RTG thereby leading to probe’s long battery life. RTG actually contains around 11 kg of plutonium-238 oxide pellets. Each of each pellet is surrounded using iridium, which in turn was encased in a graphite shell. The RTG has provided about 250 W, 30 V DC at launch, and as the probe traveled into the deep space, it dropped approximately 5% every 4 years thereby decaying to around 200 W during its encounter with the Pluto (“New Horizons begins”). In addition, RTG output is comparatively predictable, with load transients carried out by a capacitor bank along with the support of fast circuit breakers (“New Horizons begins”). Scientific goals of the mission The scientific goals of the mission are categorized into three groups, with Group 1 consisting of primary goals (which are required to be accomplished), Group 2 consisting of secondary goals (which are expected to be achieved), and finally Group 3 consisting of tertiary goals (which are desired). Among these goals, the focus is on the primary goal of characterizing the neutral atmosphere of Pluto and its escape rate and the secondary goal of searching for an atmosphere around Charon. Among the instruments in New Horizons, ALICE will only be used to measure Pluto’s neural atmospheric composition. In that direction, Nitrogen and Methane will be measured on the basis of solar UV occultation. Nitrogen densities are going to be measured through continuum absorption as well as electronic transitions from 465-1000 A (Fountain et al.). On the other hand, Methane will be detected through its continuum absorption at 1000-1300 A (Fountain et al.). Apart from these two, Carbon Monoxide and Argon can be measured using the technique of airglow observations with ALICE, although both species may be found out in the occultation spectra as well (Fountain et al.). So, by measuring or detecting these gases, the neutral atmosphere can be characterized. When it comes to Charon’s atmosphere, it is a fact that the surface gravity of Charon is less than half that of Plutos and so its primordial atmosphere is likely to have escaped since Charons origins. However, certain studies suggested the possibility of a tenuous atmosphere (Fountain et al.). So, the New Horizons mission using ALICE is expected to detect whether atmosphere is present or not. When ALICE UV observes a solar occultation by Charon, it would be able to detect an atmosphere, even going down to the nanobar range if it is actually present (Fountain et al.). So, by using ALICE and observing solar occultation, Charon’s atmosphere can be found out. NASA’s plans for New Horizons after it flies by Pluto After New Horizons probe fly past the Pluto, it will venture into a zone of space called as the Kuiper Belt. In that belt, there may be a number of icy planets or dwarf-planets, with the probe examining one or two of those mini icy worlds. The journey to those worlds, also known as Kuiper Belt Objects (KBO), will span from 2016 to 2020. The probe will focus on only one or two KBOs because of its limited maneuverings capability caused by the decaying or draining of its power source and restricted communications. So, keeping this limitation in mind, New Horizons team has already searched and focused on three potential KBOs using the Hubble Space telescope. These KBOs are provisionally designated as PT1, PT2 and PT3, with each of the objects’ diameter estimated to be in the 30–55 km range (Lakdawalla). So, based on New Horizons’ fuel budget, any one or two of these objects could be explored by the probe, after it flies past Pluto. Then, if it survives the Kuiper Belt, New Horizons is expected to proceed to the outer heliosphere, with the heliopause likely to be reached by 2047 (Lakdawalla). Debate on whether Pluto should be called a planet or not When the mission was launched, it was dubbed as the first mission to the farthest or last planet. However, given the decision by IAU to declassify Pluto, questions are being raised regarding that tag. The counter perspective put forward by Stern and the New Horizons team is that Pluto has to be regarded as a planet because planets like Pluto form the majority in the solar system. So, when majority is the norm, Pluto has to be considered as the planet. That is, few more icy planets which are bigger than Pluto have been discovered beyond it and so they predicted the number of planets in the solar system could grow. Furthermore, they opine that considering Pluto as a misfit among the other planets of the solar system is dubious because the discovery of more Pluto-like planets can make Earth as a misfit and thereby initiate a paradigm shift in the debate about Pluto’s status as planet (David). Conclusion Based on the above-analysis, it is possible to state that the New Horizons mission is a path-breaking one which would not only unravel undiscovered aspects about Pluto but also bring in newer understanding of the planet. With number of effective instruments, the New Horizons probe is expected to do a detailed and optimal study of the planet thereby presenting interesting and insightful data. So, as the limits of the human understanding of the solar system are being extended, it will lead to more discoveries which will further enrich their understanding. Works Cited Berger, Brian. “New Discoveries await out on the Horizon.” Space, 12 Dec. 2005. Web. 12 Mar. 2015. David, Leonard. “New Horizons Pluto Probe Readied for Launch.” Space, 1 Sept. 2005. Web. 12 Mar. 2015. Fountain, Glen H. et al. “The New Horizons Spacecraft.” Space Science Reviews, 140 (2008) 1-47 Lakdawalla, Emily. “Finally! New Horizons has a second target.” The Planetary Society, 15 Oct. 2014. 12 Mar. 2015. “New Horizons Full Mission Timeline.” Daniel Muller, n. d. Web. 13 Mar. 2015. “New Horizons begins Pluto observations ahead of July flyby.” NASA Spaceflight, 19 Jan. 2015. Web. 12 Mar. 2015. “Ralph Aims to Put Pluto in Focus.” NASA, 2 Mar. 2011. Web. 12 Mar. 2015. Reuter, Dennis C et al. “Ralph: A Visible/Infrared Imager for the New Horizons Pluto/Kuiper Belt Mission.” Space Science Review, 140 (2008):129-154. Stern, Alan S. “The New Horizons Pluto Kuiper belt Mission: An Overview with Historical Context.” Cornell University Library, 2007. Web. 12 Mar. 2015. Read More