The Galileo Mission
From orbit around Jupiter, the Galileo spacecraft will take the closest look ever at the planet and its natural satellites.
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From orbit around Jupiter, the Galileo spacecraft will take the closest look ever at the planet and its natural satellites.
Galileo's orbital tour at Jupiter will involve multiple close passes by the Galilean satellites, typically 10-100 times closer than Voyager encounters.
The Galileo spacecraft Energetic Particle Detector (EPD) has been used to map Jupiter's trapped electron radiation in the jovian equatorial plane for the range 8 to 16 Jupiter radii.
The SCaN Testbed is an advanced integrated communications system and laboratory facility installed on the International Space Station (ISS) in 2012. The testbed incorporates a set of new generation of Software Defined Radio (SDR) technologies intended to allow researchers to develop, test, and demonstrate new communications, networking, and navigation capabilities in the actual environment of space. Qascom, in cooperation with ESA and NASA, is designing a Software Defined Radio GalileoGPS Receiver capable to provide accurate positioning and timing to be installed on the ISS SCaN Testbed. The GalileoGPS waveform will be operated in the JPL SDR that is constituted by several hardware components that can be used for experimentations in L-Band and S-Band. The JPL SDR includes an L-Band Dorne Margolin antenna mounted onto a choke ring. The antenna is connected to a radio front end capable to provide one bit samples for the three GNSS frequencies (L1, L2 and L5) at 38 MHz, exploiting the subharmonic sampling. The baseband processing is then performed by an ATMEL AT697 processor (100 MIPS) and two Virtex 2 FPGAs. The JPL SDR supports the STRS (Space Telecommunications Radio System) that provides common waveform software interfaces, methods of instantiation, operation, and testing among different compliant hardware and software products. The standard foresees the development of applications that are modular, portable, reconfigurable, and reusable. The developed waveform uses the STRS infrastructure-provided application program interfaces (APIs) and services to load, verify, execute, change parameters, terminate, or unload an application. The project is divided in three main phases. 1)Design and Development of the GalileoGPS waveform for the SCaN Testbed starting from Qascom existing GNSS SDR receiver. The baseline design is limited to the implementation of the single frequency Galileo and GPS L1E1 receiver even if as part of the activity it will be to assess the feasibility of a dual frequency implementation (L1E1+L5E5a) in the same SDR platform.2)Qualification and test the GalileoGPS waveform using ground systems available at the NASA Glenn Research Center. Experimenters can have access to two SCaN Testbed ground based systems for development and verification: the Experimenter Development System (EDS) that is intended to provide initial opportunity for software testing and basic functional validation and the Ground Integration Unit (GIU) that is a high fidelity version of the SCaN Testbed flight system and is therefore used for more controlled final development testing and verification testing.3)Perform in-orbit validation and experimentation: The experimentation phase will consists on the collection of raw measurements (pseudorange, Carrier phase, CN0) in space, assessment on the quality of the measurements and the receiver performances in terms of signal acquisition, tracking, etc. Finally computation of positioning in space (Position, Velocity and time) and assessment of its performance.(Complete abstract in attached document).
The SCaN Testbed is an advanced integrated communications system and laboratory facility installed on the International Space Station (ISS) in 2012. The testbed incorporates a set of new generation of Software Defined Radio (SDR) technologies intended to allow researchers to develop, test, and demonstrate new communications, networking, and navigation capabilities in the actual environment of space. Qascom, in cooperation with ESA and NASA, is designing a Software Defined Radio GalileoGPS Receiver capable to provide accurate positioning and timing to be installed on the ISS SCaN Testbed. The GalileoGPS waveform will be operated in the JPL SDR that is constituted by several hardware components that can be used for experimentations in L-Band and S-Band. The JPL SDR includes an L-Band Dorne Margolin antenna mounted onto a choke ring. The antenna is connected to a radio front end capable to provide one bit samples for the three GNSS frequencies (L1, L2 and L5) at 38 MHz, exploiting the subharmonic sampling. The baseband processing is then performed by an ATMEL AT697 processor (100 MIPS) and two Virtex 2 FPGAs. The JPL SDR supports the STRS (Space Telecommunications Radio System) that provides common waveform software interfaces, methods of instantiation, operation, and testing among different compliant hardware and software products. The standard foresees the development of applications that are modular, portable, reconfigurable, and reusable. The developed waveform uses the STRS infrastructure-provided application program interfaces (APIs) and services to load, verify, execute, change parameters, terminate, or unload an application. The project is divided in three main phases. 1)Design and Development of the GalileoGPS waveform for the SCaN Testbed starting from Qascom existing GNSS SDR receiver. The baseline design is limited to the implementation of the single frequency Galileo and GPS L1E1 receiver even if as part of the activity it will be to assess the feasibility of a dual frequency implementation (L1E1+L5E5a) in the same SDR platform.2)Qualification and test the GalileoGPS waveform using ground systems available at the NASA Glenn Research Center. Experimenters can have access to two SCaN Testbed ground based systems for development and verification: the Experimenter Development System (EDS) that is intended to provide initial opportunity for software testing and basic functional validation and the Ground Integration Unit (GIU) that is a high fidelity version of the SCaN Testbed flight system and is therefore used for more controlled final development testing and verification testing.3)Perform in-orbit validation and experimentation: The experimentation phase will consists on the collection of raw measurements (pseudorange, Carrier phase, CN0) in space, assessment on the quality of the measurements and the receiver performances in terms of signal acquisition, tracking, etc. Finally computation of positioning in space (Position, Velocity and time) and assessment of its performance.(Complete abstract in attached document).
This paper provides an overview of the architecture of the Galileo spacecraft.
Galileo has completed its survey of the large moons of Jupiter.
The Galileo spacecraft has been subjected to the charged particle environment around Jupiter since 1995. There have been numerous system failures attributable to radiation effects. We summarize those failures, their causes and any associated fixes.
Since 1995, the Galileo mission, despite all the technical troubles, has provided a detailed view of the Jovian system, revealed only fleetingly in the Pioneer and Voyager flybys of the 1970s. The atmospheric probe penetrated the clouds and conducted the first in situ sampling of an outer planet's atmosphere, transmitting data for an hour before it was lost in the gaseous depths. The orbiter, which is still going strong, has photographed and analyzed the planet, its rings, and its diverse moons. Some of the results obtained so far are reviewed.
Infrared spectral images of Jupiter's volcanic moon Io, acquired during October and November 1999 flybys of the Galileo spacecraft, were used to study the thermal structure and sulfur dioxide distribution of active volcanos.
A one year follow-on to the Galileo Europa Mission (GEM) has been proposed. This extension to GEM begins in October 1999 and consists of six encounters, the first two overlapping with the last two encounters in GEM.
Unexpected energy increases during Earth flybys of both the Galileo and Near Earth Asteroid Rendzvous (NEAR) spacecraft have drawn evidence of spacecraft trajectory modeling errors, an unknown perturbing force or failure of Newtonian gravity.
The Galileo Spacecraft completed its primary mission on December 7, 1997.
Following the successful release of the Galileo Probe in July of 1995, navigation efforts forced on implementing the critical Io approach and Jupiter orbit insertion strategy that had been refined over the previous decade.
On the 7th of December, 1995 the Galileo spacecraft arrived at Jupiter. It began its mission by collecting data radioed from the Probe as it descended into Jupiter's atmosphere. A Short time later it fired its main engine for about 45 minutes, slowing the craft enough to be captured by Jupiter's gravity. The vessel named for the discovery of Jupiter's natural satellites thus became the first known artificial satellite of the giant planet.
Galileo's accomplishment of a science-rich mission through a low-gain antenna was possible by the coordinated efforts of the Deep Space Network support team, the spacecraft designers, and the science principal investigators.
Since November 1, 1996, the Galileo orbital tour of jupiter and its moons is routinely supported by a massive array of large antennas: two 70-meter antennas in GDSCC and CDSCC, a 64-meter antenna at Parkes, and additional 34-meter antennas at CDSCC. The scope of this array is unprevented, it operates daily in a routine fashion, inter-continentally, and employs antennas of several agenscies, namely two complexes of JPL's Deep Space Network (DSN) an CSIRO's Parkes facility. The Success of this routine arraying operation is the basis for the DSN's new array of 34-meter antennas that is being implementet at GDSCC.
Earth-based observations indicate that the Galileo Probe entered a 5 Mue hot spot, a region of unusual clarity and dryness. These feature was in the process of evolving both to a larger size and lower atmospheric opacity when the Probe entered on 1995 December 7.