A dataset provided by the European Space Agency

URL ftp://npsa01.esac.esa.int/pub/mirror/CASSINI-HUYGENS/DWE/HP-SSA-DWE-2-3-DESCENT-V1.0
DOI 10.5270/esa-gekm0td
Abstract N/A
Description Data Set Overview = On January 14, 2005, the Huygens Probe, part of the joint NASA/ESA Cassini-Huygens mission to Saturn, entered the atmosphere of Titan, descended for 2.5 hours under a parachute and eventually landed softly on the surface of Titan [LEBRETONETAL2005]. Six experiments collected data during the descent and on ground. The data set, which this data set catalog belongs to, is the archive of the Huygens Doppler Wind Experiment (DWE), which was designed to measure Titan's zonal winds by Doppler tracking Huygens from Cassini and from Earth [BIRDETAL2005]. In contrast to the other five experiments, DWE was not designed to collect data aboard Huygens. Instead, it was designed to measure the frequency of the Huygens carrier signal received aboard Cassini and on Earth. The radio link between Huygens and Cassini had two independent and partially redundant channels. One of them (channel A) was used for DWE Doppler tracking of Huygens. The accuracy desired by DWE required the use of special Ultra-Stable Oscillators (USO) for the channel A transmitter aboard Huygens and for the channel A receiver aboard Cassini. For the reception on Earth, a USO was not required, as the accuracy of the H-maser driven radio antennas is much higher than that of a USO. The data rate of the Huygens signal was 8 kHz. It was recorded, decoded and stored aboard Cassini in real-time for later transmission to Earth via the Cassini High Gain Antenna. The Huygens signal level was, however, to weak to be decoded on Earth. The minimum integration time for the detection of the Huygens signal on Earth was of the order of 1 sec. Due to an error in the sequence, which was executed by Cassini during the Huygens mission, the receiver USO was not switched on for the mission. Consequently, the channel A receiver aboard Cassini could not lock onto the channel A signal from Huygens and all data transmitted via this channel including the D...
Instrument DWE
Temporal Coverage 2005-01-14T10:19:27Z/2005-01-14T15:52:46Z
Version V1.0
Mission Description The majority of the text in this file was extracted from the Cassini Mission Plan Document, D. Seal, 2003. [JPLD-5564] The Cassini spacecraft, including the Huygens Probe, was launched on 15 October 1997 using a Titan IV/B launch vehicle with Solid Rocket Motor Upgrade (SRMU) strap-ons and a Centaur upper stage. The spacecraft used a 6.7-year Venus-Venus-Earth-Jupiter Gravity Assist (VVEJGA) trajectory to Saturn, during which cruise observations were conducted to check out, calibrate, and maintain the instruments as well as to perform limited science. After Saturn Orbit Insertion (SOI) (1 July 2004), the Huygens Probe separated and, on the third encounter with Titan, entered the satellite's atmosphere to make in situ measurements during an approximately 150 minute descent (14 January 2005). The Orbiter continued a tour of the Saturn system until mid-2008 collecting data on the planet and its satellites, rings, and environment. The Cassini Orbiter (CO) was a three-axis stabilized spacecraft equipped with one high gain antenna (HGA) and two low gain antennas (LGAs), three Radioisotope Thermoelectric Generators (RTGs) for power, main engines, attitude thrusters, and reaction wheels. It carried twelve orbiter instruments designed to carry out 27 diverse science investigations. The Huygens Probe (HP) was equipped with six instruments designed to study the atmosphere and surface of Titan. It entered the upper atmosphere protected by a heat shield, then deployed parachutes to descend slowly to the surface from an altitude of about 200 km. The instruments, with acronym and Principal Investigator (PI) or Team Leader (TL), are summarized below: Instrument Acronym PI/TL ----------------------------------------------- ------------ Orbiter: Cassini Plasma Spectrometer CAPS Young Cosmic Dust Analyzer CDA Srama Composite Infrared Spectrometer CIRS Flasar Ion and Neutral Mass Spectrometer INMS Waite Imaging Science Subsystem ISS Por...
Date Published 2006-07-15T00:00:00Z
Publisher And Registrant European Space Agency
Credit Guidelines European Space Agency, 2006-07-15T00:00:00Z, HP-SSA-DWE-2-3-DESCENT, V1.0. https://doi.org/10.5270/esa-gekm0td