Polar Mission Research Articles

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.

Gravitational wave searches with the galileo and solar polar missions (abstract)

Gravitational wave searches with the galileo and solar polar missions (abstract)

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.

Shuttle upper stage for Galileo

NASA has awarded four letter contracts totaling $7,483,000 for design of a modified Centaur launch vehicle and related components for use as an upper stage with the space shuttle. The modified Centaur will be an adaptation of the vehicle that has flown as an upper stage for both the Atlas and Titan boosters over the past 15 years.All of the contracts are in support of the Galileo mission to Jupiter scheduled for launch in 1985 and the International Solar Polar Mission in 1986.

Solar polar mission: Joint project saved?

Solar polar mission: Joint project saved?

Multi-spacecraft observations of solar hard X-ray bursts

The role of multi-spacecraft observations in solar flare research is examined from the point of view of solar hard X-ray bursts and their implications with respect to models of the impulsive phase. Multi-spacecraft measurements provide a stereoscopic view of the flare region, and hence represent the only direct method of measuring directivity of X-rays. In absence of hard X-ray imaging instruments with high spatial and temporal resolution, multi-spacecraft measurements provide the only means of determining the radial (vertical) structure of the hard X-ray source. This potential of the multi-spacecraft observations is illustrated with an analysis of the presently available observations of solar hard X-ray bursts made simultaneously by two or more of the following spacecraft: International Sun Earth Explorer-3 (ISEE-3), Pioneer Venus Orbiter (PVO), Helios-B and High Energy Astrophysical Observatory-A (HEAO-A). In particular, some conclusions have been drawn about the spatial structure and directivity of 50–100 keV X-rays from impulsive flares. Desirable features of future multi-spacecraft missions are briefly discussed followed by a short description of the hard X-ray experiment on the International Solar Polar Mission which has been planned specifically for multi-spacecraft observations of the Sun.

Recent developments in space-borne zodiacal light photometry

The 1985 International Solar Polar Mission will provide the first opportunity to perform measurements from out of the ecliptic and from above the solar poles. Included in this mission is the Zodiacal Light/Background Starlight Experiment of the Ruhr-University Bochum, FRG (in collaboration with the State University of New York at Albany). The experiment is based on the use of a multicolor, sky-scanning photopolarimeter, which will be carried on the NASA S/C. The scientific objectives of the experiment are to investigate the intensity, polarization, and color of the diffuse sky brightness and determine the spatial distribution and physical properties of the interplanetary dust, including a possible interstellar component, as a function of S/C position in and out of the ecliptic. The instrument will allow simultaneous measurements in two separate wavelength bands. Measurements will be performed at 180, 220, 240, 280, 320, 350, 360, 440, 540, 640, 800 nm, including the state of polarization. Two different fields-of-view (1 sq deg and 5.6 sq deg) can be selected. The use of a microprocessor system in the instrument electronics will provide flexibility in measurement sequences and programs, on-board data processing and data quality control.

Prediction of energetic particle behavior at high solar latitudes

Emphasis is placed on predictions of the galactic cosmic-ray flux at high heliographic latitudes. Recent work on gradient and curvature drifts in the large-scale heliospheric magnetic field have modified the traditional argument that the cosmic rays should be essentially unmodulated over the solar poles. In fact, drift effects during the next solar cycle, when the International Solar Polar Mission is to fly, are predicted to cause considerable modulation in the polar regions. However, it is pointed out that the use of conventional drift formulae in the solar wind, which contains magnetic-field fluctuations with large amplitudes and perhaps systematic properties, is highly suspect. Prediction of cosmic-ray behavior over the solar poles is thus currently uncertain. Also considered is the behavior of the anomalous cosmic-ray component at high heliographic latitudes.

The scientific objectives of the International Solar Polar Mission

The International Solar Polar Mission (I. S. P. M. ), originally known as the Out-of-Ecliptic Mission, will be the first spacecraft mission to explore the third dimension of the heliosphere within a few astronomical units of the Sun and to view the Sun over the full range of heliographic latitudes. Its main objectives are to investigate, as a function of solar latitude, the properties of the interplanetary medium and the solar corona. The I. S. P. M. is a two spacecraft venture jointly conducted by E. S. A. and N. A. S. A. The two spacecraft will be injected into elliptical heliocentric orbits approximately at right angles to the ecliptic plane, by using the Jupiter gravity assist method, one northwards and the other southwards. After passing nearly above the poles of the Sun, each spacecraft crosses the ecliptic plane and passes over the other solar pole. The complete mission time from launch, foreseen for February 1983, to the second polar passage is approximately 4⅔ years. This paper summarizes the main scientific objectives of the instruments to be carried on this exploratory mission. It concludes with an outline of the payload, the spacecraft, the trajectory and the mission schedule.

United States: Solar Polar Mission threatened

United States: Solar Polar Mission threatened

The Effect of Radiation Pressure on the Restricted Three-body Problem

The classical restricted three-body problem is generalized to include the force of radiation pressure and the Poynting-Robertson effect. The positions of the Lagrangian points L4and L5are found as functions of β, the ratio of radiational to gravitational forces. The Poynting-Robertson effect renders the L4and L5points unstable on a time scale (T) long compared to the period of rotation of the two massive bodies. For the solar system, T is given by T = [(1-β)2/3/β] 544 a2yr where a is the separation between the Sun and the planet in AU. Implications for space colonization and a mechanism for producing asymmetries in the interplanetary dust complex are discussed; testing the latter may be possible from the Zodiacal Light/Background Starlight Experiment aboard the International Solar Polar Mission spacecraft to be launched in 1983.

CCD Camera Systems and Support Electronics for a White Light Coronagraph and X-Ray XUV Solar Telescope

Two instruments, a White Light Coronagraph and an X-ray XUV telescope built into the same housing, share several electronic functions. Each instrument uses a CCD as an imaging detector, but due to different spectral requirements, each uses a different type. Hardware reduction, required by the stringent weight and volume allocations of the interplanetary mission, is made possible by the use of a microprocessor. Most instrument functions are software controlled with the end use circuits treated as peripherals to the microprocessor. The instruments are being developed for the International Solar Polar Mission.