Solar Polar Mission Research Articles

Orbit design and attitude control of diffractive sail and validation with solar polar mission

Liquid crystal diffractive sails can generate controllable tangential radiation pressures, which have advantages in the Solar Polar Imager mission (SPI). This paper proposes a composite diffractive sail design consisting of an ideal passive diffraction grating sail and liquid crystal polarization gratings (LCPGs). The main diffractive grating sail generates thrust for orbital transfer with a sun-facing attitude. An optimal 3.8-year transfer trajectory is obtained by an improved direct method. Small-area LCPGs distributed around the edge are used for three-axis attitude control. The LCPGs can continuously modulate the force and torque by controlling the applied voltage based on the electro-optical characteristic of liquid crystal materials. A control strategy, including an adaptive attitude-tracking PD controller and a control allocation method, is designed to track the attitude profile generated by the transfer trajectory. Finally, the attitude-orbit coupling dynamics are used to simulate the whole process, and the results show that orbital insertion errors are minor.

Enhanced transfer performance of sun-facing diffractive sails in solar polar imager missions

A diffractive sail represents an advancement in solar sailing technology, capable of generating tangential radiation pressure force when oriented towards the sun. This unique property allows for varied radiation pressure distributions, making it a potential candidate for complex space missions. This paper delves into the transfer performance of the sun-facing diffractive solar sail in a solar polar imager mission.We establish both the radiation pressure force model and the time-optimal control problem specific to the sun-facing diffractive solar sail in interplanetary transfers. Applying an indirect method and a combined approach of parameter optimization with the direct method, we explore how different diffractive angles and acceleration capacities affect transfer times. This research offers insights to the design and fabrication of thin novel optical metamaterial films that efficiently diffract light at appropriate angles for potential solar sails in the solar polar imager mission. Compared with reflective sails, the diffractive sail demonstrates remarkable transfer efficiency and simplicity in attitude control, making it a more suitable choice in the solar polar imager mission.

Solaris: A Focused Solar Polar Discovery-class Mission to achieve the Highest Priority Heliophysics Science Now

Solaris: A Focused Solar Polar Discovery-class Mission to achieve the Highest Priority Heliophysics Science Now

Sun Sailing Polar Orbiting Telescope (SunSPOT): A solar polar imaging mission design

Although the Sun has been a focus of space-based research for several decades, there are still many open questions. One severe gap in solar physics knowledge is the lack of detailed, long-term observations of the solar polar regions to explore the origins of the Sun’s magnetism and other connected phenomena.To fill this gap, this paper presents a feasibility study of a mission concept for a solar polar orbiting imaging mission called the Sun Sailing Polar Orbiting Telescope (SunSPOT). SunSPOT utilizes a doppler magnetograph instrument to observe the polar magnetic structure and a large deployable solar sail to reach high inclination orbit. The mission concept is derived from two science objectives investigating the formation of solar active regions and the solar dynamo. These objectives are aligned with the science goals formulated by the National Research Council (NRC) in the 2013 Decadal Survey in Solar and Space Physics and their science closure is shown in the Science Traceability Matrix. The mission and spacecraft design are explained, including a cost and risk analysis, with a special focus on the requirements and risks of the solar sail propulsion system. While the solar sail presents a significant design challenge and financial risk to this and other proposed solar polar missions, it is a necessity to achieve the orbit required for closure of decadal science goals. Although originally conceived of as a Discovery-class mission fitting within a $600 M budget, the solar sail pushes the cost beyond this threshold.The work presented here is the outcome of the NASA Heliophysics Mission Design School (HMDS) 2020 hosted by the NASA Jet Propulsion Laboratory.

Sun Polar Probe Trajectory Design Based on Multi-objective Genetic Algorithm

针对太阳高纬度探测器轨道设计任务要求, 研究了基于多目标遗传算法的小推力借力飞行轨道设计方法. 基于圆锥曲线拼接假设, 将探测器轨道分为小推力日心转移轨道段和木星借力飞行轨道段两部分. 在日心转移轨道段, 选择燃料最省为优化目标, 采用标称轨道法设计小推力的推力控制率. 在借力飞行轨道段, 选择借力后日心轨道倾角为优化目标, 对借力飞行的关键参数进行分析. 采用多目标遗传算法对该多目标进行了优化. 结果表明, 多目标遗传算法可以有效地解决轨道设计中的多目标优化问题. 优化得到的小推力控制率不仅可以节省发射能量, 还可以保证借力飞行后探测器能够进入太阳高纬度探测轨道.

Solar Polar Orbiter: A Solar Sail Technology Reference Study

An assessment is presented of a Solar Polar Orbiter mission as a Technology Reference Study. The goal is to focus the development of strategically important technologies of potential relevance to future science missions. The technology is solar sailing, and so the use of solar sail propulsion is, thus, defined a priori. The primary mission architecture utilizes maximum Soyuz Fregat 2-1b launch energy, deploying the sail shortly after Fregat separation. The 153 × 153 m square sail then spirals into a circular 0.48-astronomical-unit orbit, where the orbit inclination is raised to 90 deg with respect to the solar equator in just over 5 years. Both the solar sail and spacecraft technology requirements have been addressed. The sail requires advanced boom and new thin-film technology. The spacecraft requirements were found to be minimal because the spacecraft environment is relatively benign in comparison with other currently envisaged missions, such as the Solar Orbiter mission and BepiColombo.

ESA's experience with managing joint international projects

The European Space Agency (formerly ESRO), has been involved in joint international projects since its inception in 1962. These started with familiarising of European staff in space matters in the United States and the launching of the European scientific satellites (ESRO II, ESRO I and HEOS I) with US provided launchers. Then followed several joint space science missions: the International Sun-Earth Explorer (ISEE), the International Ultraviolet Explorer (IUE), the Hubble Space Telescope and Ulysses the International Solar Polar mission. Applications programmes in the post Apollo era led to a joint programme with the US Space Shuttle in which the European effort resulted in the Spacelab element still in use today. Subsequently ESA is involved in the International Space Station Program Freedom with its Columbus programme. This paper summarises these international activities from the European standpoint. It points out the motivations, benefits and difficulties experienced in each programme and the lessons learnt which could be used in any future international cooperative ventures.

Mars Observer magnetic fields investigation

The Mars Observer magnetic fields investigation will provide fast vector measurements of the Martian magnetic field over a wide dynamic range. The fundamental objectives of this investigation are (1) to establish the nature of the magnetic field of Mars, (2) to develop appropriate models for its representation, which take into account the internal sources of magnetism and the effects of the interaction with the solar wind, and (3) to map the Martian crustal remanent field to a resolution consistent with the Mars Observer orbit altitude and ground track separation. The basic instrumentation complement implemented for this mission is a synergistic combination of a dual, triaxial, flux gate magnetometer system and an electron reflectometer with sensors mounted on a spacecraft boom. The dual magnetometer system allows the real‐time estimation and correction of spacecraft‐generated fields, while the electron reflectometer provides remote magnetic field sensing capabilities. These instruments have an extensive spaceflight heritage, and similar versions of the same have been flown in numerous missions like Voyager, Magsat, International Solar Polar mission (ISPM), Giotto, Active Magnetospheric Particle Tracer Explorers, and Global Geospace Science (GGS). Depending on the telemetry rate supported, a minimum of 2–16 vector samples per second will be acquired. The instrument is microprocessor controlled, can be partially reprogrammed in flight, and supports the packet telemetry protocol implemented for Mars Observer.

Recent advances in silicon-germanium alloy technology and an assessment of the problems of building the modules for a radioisotope thermo-electric generator

This paper reviews the state of the art of silicon-germanium technology and assesses the problems of building thermoelectric modules in Europe, based upon silicon-germanium alloys, for use in a multihundred watt radioisotope thermoelectric generator. The generator developed in the United States for the International Solar Polar mission has been used as a reference system. The essential features of an alternative system, which employs thermocouples fabricated from improved silicon-germanium alloys based upon a design by the Fairchild Space and Electronics Company, is also described. It is concluded that although the fabrication of reliable electrical contacts will present a major problem, the technology is available in Europe to build thermoelectric modules similar to those developed for the International Solar Polar mission.

Cancelling the US solar-polar spacecraft

Abstract In 1981 the US spacecraft planned for the international Solar Polar Mission, in cooperation with the European Space Agency, was abruptly withdrawn. This article discusses the events leading up to the withdrawal and how it was handled by NASA and US government officials, and ESA's reaction. Reflections are offered on the experience, and ESA's current attitude towards space partnerships with the USA is examined. The author concludes the Europe is in a stronger bargaining position today, and has also advanced towards having its own autonomous space capability.

ESA plans new missions

The tragic explosion of the space shuttle Challenger has caused a delay of at least 13 months to the European Space Agency/National Aeronautics and Space Administration (ESA/NASA) cooperative mission Ulysses, previously known as the Solar Polar Mission. Ulysses was scheduled for launch in May 1986. The launch of the Hubble Space Telescope, in which ESA is a cooperative partner, is certain to be delayed beyond the October 1986 launch date.As Eos went to press, the Giotto spacecraft, which has been on its way to Comet Halley since July 1985, was performing well, according to ESA. All investigator groups participated in operation rehearsals at the European Space Operations Centre in Darmstadt, Federal Republic of Germany, in preparation for the cometary encounter, which occurred near midnight (UT) on March 13, 1986.

Shuttle science missions officially postponed

As expected, the National Aeronautics and Space Administration (NASA) postponed the Astro 1, Ulysses, and Galileo missions pending the investigation into the shuttle disaster on January 28, 1986 (Eos, February 4, 1986, p. 57). The Astro 1 visible and ultraviolet telescopes had been planned to fly in March to view Comet Halley during the times of the European, Japanese, and Russian spacecraft encounters. Ulysses (formerly the International Solar Polar Mission) had been planned for a May launch and was to have used a Jupiter swing‐by to escape the ecliptic plane. Galileo, a tandem Jupiter orbiter and probe, was also scheduled for a launch during the May “window” for Jovian missions.

The Mass-Separating Ion Spectrometer on the AMPTE Ion-Release Module

Mass-Separating Ion Spectrometer (MSIS) flown on the Ion Release Module of the AMPTE Mission was derived from a similar instrument (MASSWE) proposed and accepted for the United States spacecraft of the International Solar Polar Mission (Ulysses). It features an energy-per-charge range of 0.5 V to 14 kV, two separate systems for particle detection, each with a field of view of approximately 3° X 36°, and is distinguished from previously flown instruments by imaging capabilities in mass per charge which are employed for simultaneously detecting the ion species H+, 4He2+, 16O6+, 4He+, (7Li+; 56Fel0+; 56Fe8+), (16O2+; 56Fe7+; 56Fe6+), 16O+, (3He2+, or 137Ba+). Three different measurement modes make possible the adaption to low-energy particle measurements in an ion-release cloud, solar-wind investigations, and magnetospheric plasma measurements.

ESA/NASA Solar Polar Mission renamed Ulysses

The International Solar Polar Mission (ISPM), a joint project between the European Space Agency (ESA) and NASA, has been renamed “Ulysses.” The primary mission of the project, which has not changed with its name, is to investigate the properties of the solar wind, the structure of the sun/wind interface, the heliosphere magnetic field, the interplanetary magnetic field, the solar wind plasma, solar and galactic cosmic rays, and cosmic dust.Scheduled for launch from the space shuttle in May 1986, the Ulysses mission will make a 14‐month journey to Jupiter. That planet's gravitational effect will deflect the probe into a high‐inclination orbit toward trie sun. Reaching the sun about 2.5 years later, the satellite will take measurements over the sun's poles. The entire mission will last 5 years.

The International Solar Polar Mission – Its Scientific Investigations

ESA 1983 Noordwijk: ESA iv + 317 pp price FF175 ISSN 0379 6566 In May 1986 (d.v.), NASA and the European Space Agency will jointly launch the International Solar Polar Mission satellite. The orbit will be Jupiter-gravity assisted, and the satellite will make observations in regions of the heliosphere where the very complex solar wind, which confuses observations near the ecliptic, is expected to be absent.

Calibration of a space-borne charged particle telescope using protons in the energy range 0.4 to 20 MeV

Detailed measurements of the response to protons in the energy range 0.4 to 20 MeV of a charged particle telescope to be flown on the International Solar Polar deep-space Mission (ISPM) have been carried out using the cyclotron facility of the Free University, Amsterdam. The purpose of the measurements was two-fold; firstly to accurately calibrate the energy bandwidths of the instrument measurement channels, and secondly to study the effect of two thin foils (0.98 mg/cm 2 aluminised Kapton required for thermal control of the instrument when on the spacecraft, 0.91 mg/cm 2 titanium needed for electrical screening) which cover the telescope aperture. The particle beam used for the measurements was derived from the population of inelastically-scattered protons produced by the interaction of the primary cyclotron beam with a scattering target. The energy of the protons arriving at the telescope was selected by means of a magnetic spectrograph. This procedure enabled changes in incident energy to be made easily and with high precision. Details of the measurement technique are given, together with examples of the telescope response data.

Gamma-ray burst localization with the international solar polar mission

The European Space Agency's Solar Polar spacecraft is scheduled for launch in 1986. A solar X-ray and cosmic gamma ray burst detector will be aboard. Although the solar polar mission will not provide the long baselines originally planned, due to the cancellation of the NASA spacecraft, it is shown that arrival time analysis between the remaining ESA spacecraft and other missions will nevertheless achieve extremely precise localizations.

Centaur—The high-energy upper stage for space shuttle

General Dynamics is under contract with NASA to integrate the Centaur high-energy upper stage with the Space Shuttle. This powerful vehicle combination will deliver a Galileo spacecraft to Jupiter, launch the International Solar Polar mission, and have a 14,000-pound capability to geosynchronous orbit for large communication satellites.

NRC favors original solar mission

Following a review of alternatives to the International Solar Polar Mission (ISPM), a National Research Council panel concluded that the original mission with two space probes would provide net benefits ‘much greater’ than any of the scaled‐down options. Now slated for launch no earlier than 1986, ISPM was to be the first exploration far out of the ecliptic plane in which the planets orbit the sun.The original ISPM plans called for the European Space Agency (ESA) to build one space probe and for the National Aeronautics and Space Administration (NASA) to build the other probe, which would include X ray, extreme ultraviolet, and visible light instruments to take images of the sun. Both probes were to be launched by NASA. Budget cuts earlier this year (Eos, March 24, 1981, p, 123) halted the development of a U.S. spacecraft for ISPM. In June, following protests from ESA and others, Congress partially restored ISPM funding and requested a review of alternatives.

New design aspects for an energetic particle telescope for space missions

Describes new aspects which have been achieved in designing a charged particle <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dE</i> / <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dx</i> - <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</i> telescope to be flown on the International Solar Polar Mission. The instrument is designed to measure and resolve masses up to iron at energies above 100 keV per nucleon. Weight restrictions and radiation damage considerations led to new solutions for the overall system design and specific components. Beside radiation-resistant amplifiers, an analog-OR, a sample-and-hold circuit, and an extremely low power threshold discriminator have been developed. Power strobing of a fast ADC is another novel aspect of a `classical' measuring technique.