Giuseppe D. Racca

SMART-1 mission description and development status

Abstract SMART-1 is the first of the Small Missions for Advanced Research in Technology of the ESA Horizons 2000 scientific programme. The SMART-1 mission is dedicated to testing of new technologies for future cornerstone missions, using Solar-Electric Primary Propulsion (SEPP) in Deep Space. The chosen mission planetary target is the Moon. The target orbit will be polar with the pericentre close to the South-Pole. The pericentre altitude lies between 300 and 2000 km , while the apocentre will extend to about 10,000 km . During the cruise phase, before reaching the Moon, the spacecraft thrusting profile allows extended periods for cruise science. The SMART-1 spacecraft will be launched in the spring of 2003 as an auxiliary passenger on an Ariane 5 and placed into a Geostationary Transfer Orbit (GTO). The expected launch mass is about 370 kg , including 19 kg of payload. The selected type of SEPP is a Hall-effect thruster called PPS-1350. The thruster is used to spiral out of the GTO and for all orbit maneuvers including lunar capture and descent. The trajectory has been optimised by inserting coast arcs and the presence of the Moons gravitational field is exploited in multiple weak gravity assists. The Development Phase started in October 1999 and is expected to be concluded by a Flight Acceptance Review in January 2003. The short development time for this high technology spacecraft requires a concerted effort by industry, science institutes and ESA centres. This paper describes the mission and the project development status both from a technical and programmatic standpoint.

Moon surface thermal characteristics for moon orbiting spacecraft thermal analysis

Abstract The thermal characteristics of the funar surface are of great importance for the calculation of the surface heat flux affecting a lunar orbiting spacecraft. This paper aims to collate the existing information from the literature and systematically arrange the data in a readily usable way. Two simple surface temperature mathematical models are deyeloped, to simulate steady state and transient behaviour. The analytical model results are compared with experimental measurements and good agreement is found. Finally, the problem of the worst cases for the spacecraft thermal analysis is discussed.

SMART-1 mission to the moon: Technology and science goals

Abstract SMART-1 is a technology demonstration mission for deep space solar electrical propulsion and Technologies for the Future. SMART-1 will be Europes first lunar mission and will contribute to developing an international program of lunar exploration. The spacecraft has been readied in April 2003 for a launch in summer 2003, as an auxiliary passenger to GTO on Ariane 5, to reach the Moon after 15 months cruise. SMART-1 will carry six experiments, including three remote sensing instruments that will be used during the missions nominal six months in lunar orbit. These instruments will contribute to key planetary scientific questions, related to theories of lunar origin and evolution, the global and local crustal composition, the search for cold traps at the lunar poles and the mapping of potential lunar resources.

Capability of solar electric propulsion for planetary missions

Abstract Historically, deep space exploration was initiated by a series of flyby missions that were propulsively and energetically modest. The basic energy barrier given by the use of chemical propulsion system was not a limiting factor. Later on, the use of gravity assists has enabled missions with enlarged velocity increments. Unfortunately, multiple gravity assists have the drawback to narrow dramatically the launch windows. Moreover, the cruise phases are extremely long with obvious impacts on the operation costs. The most promising solution for the future deep space missions is found in the use of the electric propulsion (EP). Owing to its high specific impulse, the EP enables very high velocity increments, higher payload ratios and the use of smaller launchers. In addition it allows to have more flexible launch windows and ultimately reduces the cruise time. Europe possesses a variety of EP systems. Two main parameters characterise the performance of these EP systems: the specific impulse and the specific power. The first parameter is a measure of the fuel consumption, while the second is the main design driver for the on board power system. The increase in specific impulse enables missions requiring a large ΔV. However, in practice the maximum ΔV is limited to some 10 km / s , while a typical EP-based mission to Mercury requires 16 km / s . Hence, trajectories combining both low-trust and gravity-assist techniques have been devised for the ESAs BepiColombo mission. SMART-1 is a precursor mission to test these system and mission aspects.

SMART-1 technology preparation for future planetary missions

Abstract SMART-1 is the first ESA Small Mission for Advanced Research in Technology, with the prime objective of demonstrating the use of Solar Electric Primary Propulsion in a planetary mission. Further to this, SMART-1 will test novel spacecraft technologies and will host six instruments carrying out nine technology and science experiments, all aimed at preparing future ESA Cornerstones, including the ESA Mercury Cornerstone (now named BepiColombo) and other future planetary missions under study, as well as solar and fundamental physics missions.

SMART-1: The First Time of Europe to the Moon

After 40 years from the first lunar missions, Europe has started for the first time the development of a mission which has the Moon as a target. SMART-1 will be the first Western-European mission to the Earth’s satellite. The primary objective of the mission is to flight test technology innovation for the future scientific deep-space missions. This paper describes the mission concept, the technology and the scientific aspects.

The Euclid mission design

Euclid is a space-based optical/near-infrared survey mission of the European Space Agency (ESA) to investigate the nature of dark energy, dark matter and gravity by observing the geometry of the Universe and on the formation of structures over cosmological timescales. Euclid will use two probes of the signature of dark matter and energy: Weak gravitational Lensing, which requires the measurement of the shape and photometric redshifts of distant galaxies, and Galaxy Clustering, based on the measurement of the 3-dimensional distribution of galaxies through their spectroscopic redshifts. The mission is scheduled for launch in 2020 and is designed for 6 years of nominal survey operations. The Euclid Spacecraft is composed of a Service Module and a Payload Module. The Service Module comprises all the conventional spacecraft subsystems, the instruments warm electronics units, the sun shield and the solar arrays. In particular the Service Module provides the extremely challenging pointing accuracy required by the scientific objectives. The Payload Module consists of a 1.2 m three-mirror Korsch type telescope and of two instruments, the visible imager and the near-infrared spectro-photometer, both covering a large common field-of-view enabling to survey more than 35% of the entire sky. All sensor data are downlinked using K-band transmission and processed by a dedicated ground segment for science data processing. The Euclid data and catalogues will be made available to the public at the ESA Science Data Centre.

Global lunar gravity recovery from satellite-to-satellite tracking

Abstract A feasibility study is presented of high resolution and accuracy determination of the global grayity field of the Moon from a combination of low-low satellite-to-satellite range-rate observations and conventional tracking from stations on Earth. The European Moon ORbiting Observatory (MORO) mission, studied as a candidate for the third mediumsized science mission (M3) under the European Space Agencys Horizon 2000 scientific programme, is adopted for the simulation purposes. Global coverage and mapping of the fine details of the gravity field is achieved by satellite-to-satellite tracking (SST) of a small sub-satellite deployed by MORO in its 100 km polar orbit, whereas the long-wavelength features are obtained from Earth-based tracking. The combination of SST and Earth-based tracking therefore represents a powerful tool over a wide range of wavelengths. Moreover, tracking from Earth provides a clear reference for the satellite orbits, which are hard to determine from SST data only. The baseline mission proposal foresees a co-orbiting satellite pair in which the two satellites follow each other in essentially the same orbital plane with only a small spacing in time. The MORO gravimetry experiment requirements prescribe a surface level radial acceleration accuracy of a few mGal with a surface resolution of 50–100km. A number of satellite tracking configurations has been investigated and the influence of noise and systematic errors has been studied. Using perfect measurements and in the absence of systematic model errors the gravity field of the Moon, assumed to be pertectly represented by the 60 × 60 Lun60d model of Konopliv et al. (1993) with a surface resolution of 91 km, has been recovered with a radial acceleration accuracy better than 0.003 mGal using a 3° in-plane satellite spacing. Introducing uncorrelated random noise to the tracking links and a 10% model error in the direct solar radiation pressure model, still an accuracy better than 5 mGal can be achieved. Finally, it is shown that a small angular separation in right ascension of the ascending node of the orbital planes of MORO and its sub-satellite adds extra cross-track information to the SST range-rate signal and thus enables better determination of high sectorial and near-sectorial terms of the gravity field.

SMART 1: The first small mission for advanced research in technology

Abstract SMART-1 is the first of the Small Missions for Advanced Research in Technology of the ESA Horizons 2000 Science plan. The main mission objective of SMART-1 is to demonstrate innovative and key technologies for scientific deep-space missions. One of the key technologies is the solar electric propulsion used as primary propulsion. The launch is foreseen at the end of 2001 and the total life cost budget allocated to this mission is 50 million ECU (~ 65 million US dollars). Given this budget constraint, the obvious European launch system is as Piggyback passenger of an Ariane 5 in a standard GTO. This imposes stringent spacecraft mass constraints and by consequence limitations on the planetary bodies which can be reached in a given short (1.5–2 years) overall mission lifetime. Alternatively a direct injection into an escape trajectory has been considered with a small launcher, e.g. Eurockot. The planetary bodies identified are the Moon and Earth crossing asteroids or comets, generally classified as Near Earth Objects (NEO). Three mission options are currently envisaged. An Announcement of Opportunity for scientific payload, issued in March 1998, calls for scientific investigations to be performed and indication of the preferred mission options. A second Announcement of Opportunity will be issued in April 1998, concerning the technology payload. SMART-1 will also be a test case for a new approach in the implementation strategy and spacecraft procurement for the ESA Science Programme.

SMART-1 after lunar capture: First results and perspectives

SMART-1 is a technology demonstration mission for deep space solar electrical propulsion and technologies for the future. SMART-1 is Europe’s first lunar mission and will contribute to developing an international program of lunar exploration. The spacecraft was launched on 27th September 2003, as an auxiliary passenger to GTO on Ariane 5, to reach the Moon after a 15-month cruise, with lunar capture on 15th November 2004, just a week before the International Lunar Conference in Udaipur. SMART-1 carries seven experiments, including three remote sensing instruments used during the mission’s nominal six months and one year extension in lunar science orbit. These instruments will contribute to key planetary scientific questions, related to theories of lunar origin and evolution, the global and local crustal composition, the search for cold traps at the lunar poles and the mapping of potential lunar resources