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NASA NTRS2004

A Slow Streamer Blowout at the Sun and Ulysses

On 10 June 2000 a streamer on the southeast limb slowly disappeared from LASCO/C2 over approximately 10 hours. A small CME was reported in C2. A substantial interplanetary CME (ICME) was later detected at Ulysses, which was at quadrature with the Sun and SOHO at the time. This detection illustrates the properties of an ICME for a known solar source and demonstrates that the identification can be done even beyond 3 AU. Slow streamer blowouts such as this have long been known but are little studied. We report on the SOHO observation of a coronal mass ejection (CME) on the solar limb and the subsequent in situ detection at Ulysses, which was near quadrature at the time, above the location of the CME. SOHO-Ulysses quadrature was 13 June, when Ulysses was 3.36 AU from the Sun and 58.2 degrees south of the equator off the east limb. The slow streamer blowout was on 10 June, when the SOHO-Sun-Ulysses angle was 87 degrees.

Seuss, S. T.↗
NASA NTRS2022

Decadal and Annual Variations in Meteoric Flux from Ulysses, Wind, and SOFIE Observations

Our solar system is filled with meteoric particles, or cosmic dust, which is either interplanetary or interstellar in origin. Interstellar dust (ISD) enters the heliosphere due to the relative motion of the sun and the interstellar flow. Interplanetary dust (IPD) comes primarily from asteroid collisions or comet sublimation, and comprises the bulk of material entering Earth’s atmosphere. This study examines variations in ISD and the IPD flux at Earth using observations from three different satellite techniques. First are size-resolved in situ meteoroid detections by the Ulysses spacecraft, and second are in situ indirect dust observations by Wind. Third are measurements of meteoric smoke in the mesosphere by the Solar Occultation For Ice Experiment (SOFIE). Wind and Ulysses observations are sorted into the interstellar and interplanetary components. Wind ISD show the anticipated correlation to the 22-yr. solar magnetic cycle, and are consistent with model predictions of ISD. Because Wind does not discriminate particle size, the IPD measurements were interpreted using meteoric mass distributions from Ulysses observations and from different models. Wind observations during 2007-2020 indicate a total meteoric influx at Earth of 22 metric tons per day (t d(exp -1)), in reasonable agreement with long-term averages from SOFIE (25 t d(exp -1)) and Ulysses (32 t d(exp -1)). The SOFIE and Wind influx time series both show an unexpected correlation to the 22-yr. solar cycle. This relationship could be an artifact, or may indicate that IPD responds to changes in the solar magnetic field.

Meteoric influx↗
NASA NTRS1991

Ulysses

The DSN (Deep Space Network) mission support requirements for Ulysses are summarized. The primary goal of the Ulysses mission is to explore the Sun, its environment, and possible links between solar variability and terrestrial weather and climate. The Ulysses spacecraft will be injected into an interplanetary orbit toward Jupiter after which the spacecraft travels in a heliocentric, out-of-ecliptic orbit with high heliographic inclination. The Ulysses mission objectives are outlined and the DSN support requirements are defined through the presentation of tables and narratives describing the spacecraft flight profile; DSN support coverage; frequency assignments; support parameters for telemetry, command and support systems; and tracking support responsibility.

Meeks, W.↗
NASA NTRS1992

The Ulysses mission

The Ulysses mission is unique in the history of the exploration of solar system by spacecraft. The path followed by Ulysses will make it possible, for the first time, to explore the heliosphere within a few astronomical units of the sun over the full range of heliographic latitudes, thereby providing the first characterization of the uncharted third heliospheric dimension. Advanced scientific instrumentation carried on board the spacecraft is designed to measure the properties of the heliospheric magnetic field, the solar wind, the sun/wind interface, solar radio bursts and plasma waves, solar energetic particles and galactic cosmic rays, solar X-rays, and interplanetary/interstellar neutral gas and dust. Ulysses will also be used to detect cosmic gamma-ray bursts and search for gravitational waves. The mission, a collaboration between ESA and NASA, was launched in October 1990 and employs a Jupiter gravity-assist to achieve the trajectory extending to high solar latitudes. The paper describes the characteristics of the Ulysses mission in order to establish a framework within which to better understand the objectives and goals of the scientific investigations.

Wenzel, K.-P.↗
NASA NTRS1994

Engineering Ulysses extended mission

The Ulysses Mission is a collaboration between the European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA). The mission is unique, enabling exploration of the heliosphere within a few astronomical units of the Sun over a full range of heliographic latitudes adding a third dimension to our understanding of the Solar System. The advanced scientific instrumentation on Ulysses continually measures the properties of the heliospheric magnetic field, the solar wind, solar radio bursts and plasma waves, galactic cosmic rays, energetic particles, solar X-rays, and interstellar neutral gas. By the end of 1995, the spacecraft will have completed measurements at heliographic latitudes up to 80 degrees over a single orbit of the Sun. The properties of the heliosphere are solar cycle dependent, and Ulysses' first orbit of the Sun will have taken place around a solar minimum. In order to characterize the heliosphere over a full (11 year) solar cycle, it is desirable to continue measurements over a second orbit of the Sun, a new Odyssey that will extend through 2001. Since the spacecraft was only designed for a five-year mission, a number of technical challenges have been surmounted in order to demonstrate the engineering feasibility of this unparalleled scientific opportunity. This paper describes the changes that were necessary to the Ulysses mission engineering and mission operations in order to ensure continual, effective payload operation throughout 1996-2001.

Standley, Shaun↗
NASA NTRS1993

Ulysses observations of a recurrent high speed solar wind stream and the heliomagnetic streamer belt

Near-ecliptic solar wind observations by Ulysses on its way to the polar regions of the Sun, compared with those from IMP 8 at 1 AU, showed that high-speed streams decay and broaden with heliocentric distance from IMP 8 to Ulysses, as expected. In July 1992 while traveling south at approximately 13 deg S and 5.3 AU, Ulysses encountered a recurrent high-speed stream, that may also have been observed at IMP 8. The stream has been observed a total of 14 times, once in each solar rotation through June 1993 at approximately 34 deg S. The source of the high-speed stream is an equatorward extension of the south polar coronal hole. From July 1992 through June 1993, averages of solar wind peak speed increased while density decreased with heliographic latitude. Both the stream and a low-speed, high-density flow, presumably associated with the heliomagnetic (coronal) streamer belt encircling the heliomagnetic equator, crossed Ulysses with the solar rotation period until April 1993 when the spacecraft was at approximately 29 deg S heliographic latitude. After this time, as the spacecraft climbed to higher latitudes, the central portion of the streamer belt with lowest speed and highest density disappeared. Therefore, at its maximum inclination, the belt was tilted at approximately 29 deg to the heliographic equator at this point in the solar cycle.

Bame, S. J.↗
NASA NTRS1995

Detectability of electrostatic decay products in Ulysses and Galileo observations of type 3 solar radio sources

Recent in situ Ulysses and Galileo observations of the source regions of type 3 solar radio bursts appear to show an absence of ion acoustic waves S produced by nonlinear Langmuir wave processes such as the electrostatic (ES) decay, in contradiction with earlier ISEE 3 observations and analytic theory. This letter resolves these apparent contradictions. Refined analyses of the maximum S-wave electric fields produced by ES decay and of the characteristics of the Ulysses Wave Form Analyzer (WFA) instrument show that the bursty S waves observed by the ISEE 3 should be essentially undetectable by the Ulysses WFA. It is also shown that the maximum S-wave levels predicted for the Galileo event are approximately less than the instrumental noise level, thereby confirming an earlier suggestion. Thus, no contradictions exist between the ISEE 3 and Ulysses/Galileo observation, and no evidence exists against ES decay in the published Ulysses and Galileo data. All available data are consistent with, or at worst not inconsistent with, the ES decay proceeding and being the dominant nonlinear process in type 3 bursts.

Cairns, Iver H.↗
NASA NTRS1995

Kilometric type 3 radio bursts observed from high southern ecliptic latitudes by Ulysses

The Ulysses URAP experiment has provided the first measurements of remote and in-situ wave phenomena from high southern latitudes. Remote sensing of type 3 solar radio bursts constitute an important component of the Ulysses observations. Type 3 radio emissions, which have never before been viewed from outside the ecplitic plane, have been observed by Ulysses to its maximum southern latitude (approximately 80 deg S), although their frequency of occurrence has generally diminished due to the declining phase of the solar cycle. In addition, the Ulysses radio receiver measures both the direction of arrival and the complete polarization state of incident radiation. These physical parameters provide information on the origin and nature of the radio emission. Preliminary analyses have indicated that kilometric type 3 radiation is often approximately 10-20% circularly polarized at the highest URAP frequencies. New directional information provides crucial information on the effects of beaming and scattering of the radiation in the interplanetary medium.

Reiner, M. J.↗
NASA NTRS1995

Helium abundance variations in the solar wind: Observations from Ulysses

The abundance of helium in the solar wind averages approximately 4% but has been observed to vary by more than two orders of magnitude from 0.1 to 30%. Physical processes responsible for this variability are still not clearly understood. Previous work has shown a correlation between low He abundance and coronal streamer plasma and between high He abundance and coronal mass ejections (CMEs). We now have out-of-ecliptic data on helium in the solar wind from the plasma experiment aboard Ulysses. Tentative results show that the average high-latitude helium concentration is comparable to the in-ecliptic value for the present phase of the solar cycle, that excursions of the hour-averaged abundance very seldom fall outside the range 2.5 to 6.5%, and that there seems to be very little abundance enhancement associated with CMEs encountered at latitudes greater than 30 deg as opposed to the situation commonly encountered with in-ecliptic CMEs. In addition, preliminary observations of a single CME by both ISEE (in-ecliptic) and Ulysses (out-of-ecliptic) show a considerable He enhancement at ISEE with little or no perturbation of the average value at Ulysses' location. This paper will first present new results from the Ulysses mission up to the time of the meeting on the average abundance of helium in the solar wind as a function of spacecraft position, and will then focus on the out-of-ecliptic results including latitudinal abundance variations and observations of abundance enhancements (or lack thereof) in high-latitude CMEs.

Barraclough, B. L.↗
NASA NTRS1996

Modeling of Jovian Hectometric Radiation Source Locations: Ulysses Observations

The Unified Radio and Plasma Wave (URAP) experiment on Ulysses has provided unique high latitude measurements of Jovian hectometric radiation (HOM) during its encounter with Jupiter in February 1992. URAP was the first radio instrument in the Jovian environment with radio direction-finding capability, which was previously used to determine the HOM source locations in the Jovian magnetosphere. These initial source location determinations were based on several assumptions, including the neglect of refractive effects, which may be tested. We have, for the first time, combined the measured incident ray-direction at the spacecraft with a model magnetosphere to directly trace the rays back to the HOM source. We concentrate on the observations of HOM from high northern latitudes when Ulysses was at distances less than 15 R(sub j). The three- dimensional ray-tracing calculations presented here indicate that the HOM sources probably lie on L shells in the range 3 less than or approximately equal to L less than 7 (tilted dipole magnetic field model) consistent with previous determinations that ignored the effects of refraction. The ray-tracing results, however, indicate that wave refraction due to the Io torus and the magnetic field can significantly influence the precise source location. We show that constraints on the locations imposed by the gyroemission mechanism suggest that the lo torus density may have experienced temporal and/or spatial fluctuations during the Ulysses observations of HOM. Finally, in the cold plasma approximation we demonstrate that even if the emission were nearly linearly polarized near the source region, almost circular polarization will be observed at Ulysses, in agreement with observations.

Menietti, J. D.↗
NASA NTRS1998

Ulysses: UVCS Coordinated Observations

We present results from coordinated observations in which instruments on Solar and Heliospheric Observatory (SOHO) and Ulysses were used to measure the density and flow speed of plasma at the Sun and to again measure the same properties of essentially the same plasma in the solar wind. Plasma was sampled by Ultraviolet Coronagraph Spectrometer (UVCS) at 3.5 and 4.5 solar radii and by Ulysses/SWOOPS at 5 AU. Data were acquired during a nearly 2 week period in May-June 1997 at a latitude of 9-10 degrees north of the equator, on the east limb and, hence, in the streamer belt and the source location of slow wind. Density and outflow speed are compared, in order to check for preservation of the near Sun characteristics in the interplanetary medium. By chance, Ulysses was at the very northern edge of the visible streamer belt. Nevertheless, no evidence of fast wind, or mixing with fast wind coming from the northern polar coronal hole, was evident at Ulysses. The morphology of the streamer belt was similar at the beginning and end of the observation period, but was markedly different during the middle of the period. A corresponding change in density (but not flow speed) was noted at Ulysses.

Suess, S. T.↗
NASA NTRS2001

Low-Latitude Solar Wind During the Fall 1998 SOHO-Ulysses Quadrature

The Fall 1998 SOlar-Heliospheric Observatory (SOHO) - Ulysses quadrature occurred when Ulysses was at 5.2 AU, 17.4 deg South of the equator, and off the West line of the Sun. SOHO coronal observations, at heliocentric distances of a few solar radii, showed that the line through the solar center and Ulysses crossed, over the first days of observations, a dark, weakly emitting area and through the northern edge of a streamer complex during the second half of the quadrature campaign. Ulysses in situ observations showed this transition to correspond to a decrease from higher speed wind typical of coronal hole flow to low speed wind. Physical parameters (density, temperature, flow speed) of the low latitude coronal plasma sampled over the campaign are determined using constraints from what is the same plasma measured later in situ and simulating the intensities of the Hydrogen Lyman-alpha and OVI 1032 and 1037 Angstrom lines, measured by the Ultra Violet Coronagraph Spectrometer (UVCS) on SOHO. The densities, temperatures and outflow speed are compared with the same characteristic flow parameters for high-latitude fast wind streams and typical slow solar wind.

Poletto, G.↗
NASA NTRS2004

A Detection of the Same Hot Plasma in the Corona: During a CME and Later at Ulysses

We show direct evidence for the same very hot plasma being detected remotely from SOHO in the corona and subsequently, at Ulysses in the solar wind. This is, to our knowledge, the first time that such an unambiguous identification has been made in the case of hot plasma. This detection complements studies correlating other plasma and field properties observed to the properties measured at the source in the corona. This observation takes advantage of a SOHO-Sun-Ulysses quadrature, during which the Sun-Ulysses included angle is $90^\circ$ and it is possible to observe with Ulysses instruments the same plasma that has previously been remotely observed with SOHO instruments in the corona on the limb of the Sun. The identification builds on an existing base of separate SOHO and interplanetary detections of hot plasma. SOHO/UVCS has found evidence for very hot coronal plasma in current sheets in the aftermath of CMEs in the [Fe XVIII] $\lambda$ \AA\ line, implying a temperature on the order of $6\times 10(exp 6)$ K. This temperature is unusually high even for active regions, but is compatible with the high temperature predicted in current sheets. In the solar wind, ACE data from early 1998 to middle 2000 revealed high frozen-in Fe charge state in many cases to be present in interplanetary plasma.

Suess, S. T.↗
NASA NTRS1990

Ulysses Launch

Ulysses is a joint mission between the United States National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA) to explore the heliosphere over the full range of solar latitudes, especially in the polar regions. The goal of the Ulysses mission is to provide an accurate assessment of our total solar environment. This collaborative ESA/NASA mission will, for the first time, explore the heliosphere -- the region of space that is dominated by the Sun-- within a few astronomical units of the Sun over the full range of heliographic latitudes. The path followed by the spacecraft, using a Jupiter gravity-assist to achieve a trajectory extending to high solar latitudes, will enable the highly sophisticated scientific instruments on board to make measurements in the uncharted third dimension of the heliosphere. The Ulysses spacecraft will carry nine scientific instruments to measure the properties of the solar corona, the solar wind, the Sun/wind interface, the heliospheric magnetic field, solar radio bursts, plasma waves, solar X-rays, solar and galactic cosmic rays, and the interplanetary/interstellar neutral gas and dust. Scientists will take advantage of the enormous distance between the spacecraft and the Earth to perform astrophysical measurements and to search for gravitational waves. In conjunction with instrumentation on Earth-orbiting spacecraft, Ulysses will help to precisely locate the mysterious sources of cosmic gamma bursts. The results obtained will help to solve outstanding problems in solar and heliospheric physics, while undoubtedly revealing new and unanticipated phenomena.

Source record↗
NASA NTRS2007

SOHO-Ulysses Coordinated Studies During the Two Extended Quadratures and the Radial Alignment of 2007-2008

During quadrature, plasma seen on the limb of the Sun, along the radi al direction to Ulysses, by SOHO or STEREO can be sampled in situ as lt later passes Ulysses. A figure shows a coronagraph image, the rad ial towards Ulysses at 58 deg. S. and the SOHO/UVCS slit positions d uring one set of observations. A CME subsequently occurred and passed Ulysses (at 3/4 AU) 15 days later.

Suess, S. T.↗
NASA NTRS1988

An analytic-geometric model of the effect of spherically distributed injection errors for Galileo and Ulysses spacecraft - The multi-stage problem

In previous work the problem of injecting the Galileo and Ulysses spacecraft from low earth orbit into their respective interplanetary trajectories has been discussed for the single stage (Centaur) vehicle. The central issue, in the event of spherically distributed injection errors, is what happens to the vehicle? The difficulties addressed in this paper involve the multi-stage problem since both Galileo and Ulysses will be utilizing the two-stage IUS system. Ulysses will also include a third stage: the PAM-S. The solution is expressed in terms of probabilities for total percentage of escape, orbit decay and reentry trajectories. Analytic solutions are found for Hill's Equations of Relative Motion (more recently called Clohessy-Wiltshire Equations) for multi-stage injections. These solutions are interpreted geometrically on the injection sphere. The analytic-geometric models compare well with numerical solutions, provide insight into the behavior of trajectories mapped on the injection sphere and simplify the numerical two-dimensional search for trajectory families.

Longuski, James M.↗
NASA NTRS1989

The solar flare and cosmic gamma-ray burst experiment aboard the Ulysses spacecraft

The HUS-Ulysses team has prepared an instrument for the Ulysses spacecraft consisting of 2 Csi detectors and 2 Si surface barrier detectors for measuring x rays in the range 5 to 200 keV with up to 8 ms time resolution. The prime objectives of the experiment are the study of solar flares and cosmic gamma-ray bursts. The Ulysses mission will leave the ecliptic during the forthcoming solar maximum. The total time above ecliptic latitudes + or - 70 degrees is expected to be 230 days. The solar data can be used in conjunction with other experiments to measure the directivity of the emission and for correlative studies.

Boer, Michel↗
NASA NTRS1990

Final Environmental Impact Statement for the Ulysses Mission (Tier 2)

This Final (Tier 2) Environmental Impact Statement (FEIS) addresses the environmental impacts which may be caused by implementation of the Ulysses mission, a space flight mission to observe the polar regions of the Sun. The proposed action is completion of preparation and operation of the Ulysses spacecraft, including its planned launch at the earliest available launch opportunity on the Space Transportation System (STS) Shuttle in October 1990 or in the backup opportunity in November 1991. The alternative is canceling further work on the mission. The Tier 1 EIS included a delay alternative which considered the Titan 4 launch vehicle as an alternative booster stage for launch in 1991 or later. This alternative was further evaluated and eliminated from consideration when, in November 1988, the U.S. Air Force, which procures the Titan 4, notified that it could not provide a Titan 4 vehicle for the 1991 launch opportunity because of high priority Department of Defense requirements. The Titan 4 launch vehicle is no longer a feasible alternative to the STS/Inertial Upper Stage (IUS)/Payload Assist Module-Special (PAM-S) for the November 1991 launch opportunity. The only expected environment effects of the proposed action are associated with normal launch vehicle operation and are treated elsewhere. The environmental impacts of normal Shuttle launches were addressed in existing NEPA documentation and are briefly summarized. These impacts are limited largely to the near-field at the launch pad, except for temporary stratospheric ozone effects during launch and occasional sonic boom effects near the landing site. These effects were judged insufficient to preclude Shuttle launches. There could also be environmental impacts associated with the accidental release of radiological material during launch, deployment, or interplanetary trajectory injection of the Ulysses spacecraft. Intensive analysis indicates that the probability of release is small. There are no environmental impacts in the no-action alternative; however, the U.S. Government and the European Space Agency would suffer adverse fiscal and programmatic impacts if this alternative were adopted. The scientific benefits of the mission would be delayed and possibly lost. There could be significant impacts on the ability of the U.S. to negotiate international agreements for cooperative space activities.

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