Solar electric space mission analysis Progress report, 1 Jun. - 31 Dec. 1966
Characteristics and trajectory analysis of solar electric propulsion space missions - Mars orbiter and Jupiter flyby
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Characteristics and trajectory analysis of solar electric propulsion space missions - Mars orbiter and Jupiter flyby
Data from the Pioneer 10 and 11 missions to Jupiter and beyond are used in a study of solar flare accelerated particles at distances of several astronomical units from the sun. The intensity-time profiles out to at least 6 AU are consistent with mainly diffusive interplanetary propagation. The outer boundary of the diffusion region is thought to be beyond 10 AU, since no obvious effects of a free escape boundary were observed. Four solar particle events are discussed in detail. The events are interpreted in terms of a spherically symmetric propagation model which includes the effects of diffusion, convection, and adiabatic deceleration and which assumes that the particles are impulsively injected at the sun.
As the interest in exploring icy and ocean worlds gains increasing traction among scientists and mission communities, there are many potential icy and ocean world targets for in-situ lander missions. Potential targets include Europa, Enceladus, Titan, Triton, Ceres, Pluto, and more, which will allow the scientific community to address icy and ocean world related questions for understanding the distribution of life in the Solar System. Beyond Jupiter, solar power is infeasible for any landed missions and primary batteries are infeasible for long-duration missions. Radioisotope Power Systems (RPS) can be enabling for these long-duration in-situ missions. However, the interaction of RPS waste heat with icy world surfaces must be understood to assure the science and mission communities that RPS are a safe, enabling option to explore the surface of icy bodies. This paper describes a study for the RPS Program that was conducted by the RPS Mission Analysis Team and JPL’s Team X to investigate the system-level impact of a heat rejection system that would be required for RPS-enabled exploration of icy and ocean worlds.
Electric propulsion ion engine systems using solar power source for Mars and Jupiter exploratory unmanned spacecraft is adaptable to existing launch vehicles
Ground processing and operation activities for selected automated and sortie payloads are evaluated. Functional flow activities are expanded to identify payload launch site facility and support requirements. Payload definitions are analyzed from the launch site ground processing viewpoint and then processed through the expanded functional flow activities. The requirements generated from the evaluation are compared with those contained in the data sheets. The following payloads were included in the evaluation: Long Duration Exposure Facility; Life Sciences Shuttle Laboratory; Biomedical Experiments Scientific Satellite; Dedicated Solar Sortie Mission; Magnetic Spectrometer; and Mariner Jupiter Orbiter. The expanded functional flow activities and descriptions for the automated and sortie payloads at the launch site are presented.
Since 1960s NASA’s missions have spanned the entire solar system, from Apollo to Jupiter entry ~50 km/s. Ablative TPS has been critical to the success. NASA’s missions will continue to be innovative, one-of-a kind and at the same time, competed mission selection process requires technology readiness to be high to ensure cost and risks are better understood. If missions require new TPS technology, it takes a decade and significant resources to develop them. Competitive proposal tend to use existing ablative TPS. Sustainability of ablative TPS is then essential. This talk will focus on approaches to address the future challenges.
NASA is currently considering a mission to investigate the moons of Jupiter. When designing a spacecraft for this type of mission, there are a number of engineering challenges, especially if the mission chooses to utilize solar arrays to provide the spacecraft power. In order for solar arrays to be feasible for the mission, their total mass needed to fit within the total budget for the mission, which strongly suggested the use of carbon composite facesheets on an aluminum core for the panel structure. While these composite structures are a good functional substitution for the metallic materials they replace, they present unique challenges when interacting with the harsh Jovian space environment. As a composite material, they are composed of more than one material and can show different base properties depending in differing conditions. Looking at the electrical properties, in an Earth-based environment the carbon component of the composite dominates the response of the material to external stimulus. Under these conditions, the structures strongly resembles a conductor. In the Jovian environment, with temperatures reaching 50K and under the bombardment from energetic electrons, the non-conducting pre-preg binding materials may come to the forefront and change the perceived response. Before selecting solar arrays as the baseline power source for a mission to Jupiter, the response of the carbon composites to energetic electrons while held at cryogenic temperatures needed to be determined. A series of tests were devised to exam the response of a sample solar array panel composed of an M55J carbon weave layup with an RS-3 pre-preg binder. Test coupons were fabricated and exposed to electrons ranging from 10 keV to 100 keV, at 1 nA/cm2, while being held at cryogenic temperatures. While under electron bombardment, electrical discharges were observed and recorded with the majority of discharges occurring with electron energies of 25 keV. A decrease in temperature to liquid nitrogen temperatures showed a marked increase in the magnitude of these discharges. The results indicate that dielectric discharges are primarily produced due to the presence of large regions of the non-conductive pre-preg on the surface of the carbon sheets. The frequency and magnitude of discharges decreased when layers of the pre-preg material were removed from the composite surface. These tests indicate that solar array panels may be used in the Jovian environment, but that electrostatic discharges can be expected on the carbon composite solar arrays.
A collection of optimum trajectory and spacecraft data is presented for unmanned interplanetary missions from 1975 to 1990 using solar electric propulsion. Data are presented for one-way flyby and orbiter missions from Earth to Venus, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. The solar system model assumes planetary ephemerides which very closely approximate the true motion of the planets. Direct and indirect flight profiles are investigated. Data are presented for two representative flight times for each mission. The launch vehicle is the Titan 3 B (core)/Centaur, and a constant jet exhaust speed solar electric propulsion system having a specific mass of 30 kg/kw is completely optimized in terms of power level and jet exhaust speed to yield maximum net spacecraft mass. The hyperbolic excess speeds at departure and arrival and the launch date are optimized for each mission. For orbiter missions, a chemical retro stage is used to brake the spacecraft into a highly eccentric capture orbit about the target planet.
In response to the recommendations by the National Research Council (NRC), NASA's Solar System Exploration (SSE) Roadmap identified the in situ exploration of Venus and Jupiter as high priority science objectives. For Jupiter, deep entry probes are recommended, which would descend to approx.250 km - measured from the 1 bar pressure depth. At this level the pressure would correspond to approx.100 bar and the temperature would reach approx.500(deg)C. Similarly, at the surface of Venus the temperature and pressure conditions are approx.460(deg)C and approx.90 bar. Lifetime of the Jupiter probes during descent can be measured in hours, while in{situ operations at and near the surface of Venus are envisioned over weeks or months. In this paper we discuss technologies, which share commonalities in mitigating these extreme conditions over proposed mission lifetimes, specially focusing on pressure and temperature environments.
A mission close to the sun is only possible if new spacecraft technologies can be developed and incorporated into a state-of-the-art spacecraft concept. The perihelion goal of 4 solar radii requires a shielded spacecraft that can tolerate the 3000 suns solar flux while maintaining the electronics components at room temperature. In addition, the shield surface should sublimate at a rate of less than 3 mg/s at perihelion. Many shield configuration designs have been studied and the most promising is a parabolic shape that functions as both a shield and a large high gain antenna. The shield material chosen for this design is a carbon-carbon material with highly emissive surface properties. A mission requirement for a high telecommunications power stems from the expected interference when attempting to transmit data through the solar corona. It is expected that the large carbon-carbon shield/antenna will have a large power gain even at high temperatures and will return adequate telemetry at the X-band radio frequency chosen for the Solar Probe mission. Other key technology needs include a non-nuclear power subsystem that can function in the extreme environments of the mission from Earth to Jupiter and onward to a 4 solar radii perihelion.
The possible future of the United States program of planetary exploration in the next two decades is examined. The scientific goals and strategy for the exploration of the solar system outside of the earth-moon system are outlined, and the increasing cost effectiveness (per bit of data returned) of the first two decades of space exploration is pointed out. Attention is then given to the next two missions which are currently authorized and under development, the Galileo Jupiter orbiter and descent probe mission and the International Solar Polar Mission, and to possible missions for the next two decades, which would require additional thrust capabilities, including cometary missions, the Venus Orbiting Imaging Radar mission, a follow-on solar probe mission, a Saturn-Titan dual probe, and a Mars sample return mission.
Research and development of silicon solar cells for low solar intensity and low temperature operation on Jupiter mission
The Office of Space Science at NASA Headquarters has a current staff of about 60 professionals (aka, scientists, engineers, budget analysts) and an annual budget of $2.5 B out of NASA s $15.0 B. About 35 missions or programs in various stages of development or operation are managed by OSS, notable among them are Hubble Space Telescope, Mars Global Surveyor, Mars 2001 Odyssey, Chandra X-ray Observatory, TRACE (solar observatory), Cassini (mission to Saturn), Galileo (mission at Jupiter), and Next Generation Space Telescope. OSS has an annual technology budget of several hundred million dollars. So, what is it that we are doing?
This report covers progress to date under this grant on our continuing program to conduct ground based studies of the outer solar system planets and satellites, with emphasis on spectroscopy and atmospheric phenomena. The research continues under our new PAST grant, NNG04G131G beginning 5/1/2004. The original period of performance of the subject grant was 3/1/2001 to 2/28/2004, but was extended one year at no cost. Although there is some overlap in the scientific projects conducted during the extended year with those of the new grant, this report is confined to the portion of the work funded under NAG5-10435. The primary goals for this grant period were a comparative study of outer planet thermospheres/ionospheres near solar maximum, extended to the mid-IR, and the investigation of molecular dimers in outer solar system atmospheres. This project supports NASA's planned space missions, Jupiter Polar Orbiter, outer Planet Microprobes, and the recent Cassini flyby of Jupiter. It also supports the OSS strategic plan themes, The Exploration of the Solar System and The Sun-Earth Connection/ Understanding comparative planetary space environments.
As part of NASA's new deep space exploration system, the Space Launch System (SLS) will provide the United States with guaranteed access to deep space and an unparalleled capability for launching primary and co-manifested payloads beyond Earth's orbit. Planned missions for the new SLS family of vehicles include launching the Orion spacecraft and elements of the new Gateway astronaut-tended outpost to lunar orbit and sending robotic probes deep into the solar system, such as to Jupiter's moon Europa. If mission parameters allow, secondary payloads in 6U, 12U or larger sizes will also have rideshare opportunities, providing CubeSats with access to deep space. The SLS vehicle will evolve into progressively more powerful variants with fairings in several sizes available to meet an array of mission needs. Superior mass, volume and characteristic energy (C3) enable sending larger, heavier payloads to a variety of destinations. Several elements of the Block 1 vehicle for the first mission, Exploration Mission-1 (EM-1) are complete and have been delivered to the Exploration Ground Systems (EGS) Program at Kennedy Space Center (KSC), which has responsibility for integrating and launching the vehicle. Contractors are already at work manufacturing the second Block 1 vehicle and incorporating numerous lessons learned in manufacturing America's first super heavy-lift deep space rocket since the Apollo Program's Saturn V enabled humankind to take a giant leap forward.
Europa, the fourth largest moon of Jupiter, is believed to be one of the best places in the solar system to look for extant life beyond Earth, and the Europa Clipper Mission is preparing to investigate. Now entering the fifth year of life as a formal project, the Europa Clipper Mission has completed its major design phase and is preparing for implementation. The mission envisions sending a flight system, consisting of a spacecraft equipped with a payload of NASA-selected scientific instruments, to execute numerous flybys of Europa while in Jupiter orbit. The mission is being formulated and implemented by a joint Jet Propulsion Laboratory (JPL) and Applied Physics Laboratory (APL) Project team. At the Project Preliminary Design Review (PDR) in August 2018, it was determined that the unique integration of the REASON instrument’s antennas with the spacecraft’s solar arrays required additional time for maturity and review. The required maturity was demonstrated, and in June 2019 the Clipper Mission passed its Delta Preliminary Design Review, and formal confirmation for entry into Phase C was announced by NASA in August 2019. The earliest launch opportunity is now in July 2023, one year later than originally planned. The Project is now working toward its Critical Design Review in May 2020. This paper will describe the progress of the Europa Clipper Mission since January 2019, including maturation of the spacecraft, subsystem and instrument designs, the beginning of fabrication of engineering models and the first flight models, planning for the verification & validation phase, and planning for operations.
We present the discovery and characterization of five hot and warm Jupiters—TOI-628 b(TIC 281408474; HD288842), TOI-640 b(TIC 147977348), TOI-1333 b (TIC 395171208, BD+47 3521A), TOI-1478 b (TIC409794137), and TOI-1601 b (TIC 139375960)—based on data from NASA’s Transiting Exoplanet Survey Satellite(TESS). The five planets were identified from the full-frame images and were confirmed through a series of photometric and spectroscopic follow-up observations by the TESS Follow-up Observing Program Working Group. The planets are all Jovian size (RP=1.01–1.77RJ) and have masses that range from 0.85 to 6.33MJ. The host stars of these systems have F and G spectral types (5595Teff 6460 K)and are all relatively bright (9.5 1.7RJ, possibly a result of its host star’s evolution) and resides on an orbit with a period longer than 5 days. TOI-628 b is the most massive, hot Jupiter discovered to date by TESS with a measured mass of-+6.310.300.28MJ and a statistically significant, nonzero orbital eccentricity of e=-+0.0740.0220.021. This planet would not have had enough time to circularize through tidal forces from our analysis, suggesting that it might be remnant eccentricity from its migration. The longest-period planet in this sample, TOI-1478 b (P=10.18 days), is a warm Jupiter in a circular orbit around a near-solar analog. NASA’s TESS mission is continuing to increase the sample of well-characterized hot and warm Jupiters, complementing its primary mission goals.
The management of the Ulysses project, a probe which will fly a solar polar orbit, is described. The 5-yr mission will feature a flyby of Jupiter to deflect the spacecraft into a high-inclination orbit. Data on the solar corona, solar wind, the sun-wind interface, the heliospheric magnetic field, solar and nonsolar cosmic rays, etc., will be gathered as a function of the solar latitude. NASA will track and control the probe with the Deep Space Network. JPL provides project management for NASA while the Directorate of Scientific Programs performs ESA management functions. The DOE will provide a radioisotope thermoelectric generator while NASA and ESA each supply half the scientific payload. A NASA-ESA Joint Working Group meets about twice per year to monitor the project and discuss the technical and scientific requirements. Safety issues and measures which are being addressed due to the presence of the Pu-238 heat source for the RTG are discussed.