ALICE is a UV spectrometer that will monitor the sublimation rates of water vapor and carbon monoxide/dioxide.
Principal Investigator: S. A. Stern, SwRI, Boulder, Co, USA.
CONSERT (COmet Nucleus Sounding Experiment by Radiowave Transmission) will transmit radiowaves that will penetrate the cometary nucleus (and received by the CONSERT on the lander) to probe the inhomogeneity of the nucleus as an assemblage of component "cometesimals".
Principal Investigator: W. Kofman, LPG, Grenoble, France
COSIMA (COmetary Secondary Ion Mass Analyzer) will analyze the composition of key atomic elements and organic molecules in the cometary dust (in the tail).
Principal Investigator: J. Kissel, MPAe, Katlenburg-Lindau, Germany.
GIADA (Grain Impact Analyzer and Dust Accumulator) will measure the number, mass, momentum and velocity distribution of the dust grains.
Principal Investigator: L. Colangeli, Oss Astronomico di Capodimonte, Naples, Italy.
MIDAS (Micro-Imaging Dust Analysis System) will provide the population, size, volume and shape of the grains.
Principal Investigator: W. Riedler, IWF, Graz, Austria.
MIRO (Microwave Instrument for Rosetta Orbiter) is a radiometer that will monitor the surface temperature of the comet (and a few asteroids during its cruise phase). It will also monitor the abundance of water vapor and carbon monoxide, to determine how the sublimation varies according to the distance from the Sun.
Principal Investigator: S. Gulkis, NASA-JPL, Pasadena, CA, USA.
OSIRS (Optical, Spectroscopic, and Infrared Remote-imaging System) is a joint wide-angle and narrow-angle panchromatic camera to photograph the cometary nucleus.
Principal Investigator: H. U. Keller, MPAe, Katlenburg-Lindau, Germany.
ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) carries two sensors to determine the composition of the comet's atmosphere and ionosphere, and the velocities of ions.
Principal Investigator: H. Balsiger, University of Bern, Switzerland.
RPC (Rosetta Plasma Consortium) carries five sensors to measure the physical properties of the cometary nucleus, examine the structure of the inner coma, monitor cometary activity, and study the comet's interaction with the solar wind.
Principal Investigator: R. Lundin, Swedish Institute of Physics, Kiruna, Sweden et al.
RSI (Radio Science Investigation) will infer the ionization in the cometary environment by analyzing Rosetta's telemetry waves that passed through the environment on the way to Earth.
Principal Investigator: M. Patzold, University of Cologne, Germany.
VIRTIS (Visible and InfraRed Thermal Imaging Spectrometer) will map the nature of the solids, and the temperature of the nucleus' surface. It will also identify the gases in the coma and help identify a suitable landing site.
Principal Investigator: A. Coradini, IFSI, Rome, Italy.
Philae is the lander of mass 100 kg, and is covered by solar panels. It will unfold its three legs upon release from the orbiter, which will help to damp out the impact and enable the lander to stand upright. Upon landing, it will fire a harpoon to anchor it to the soil. The data from the instruments will be sent to the ground stations via the orbiter.
It has three Project Managers:
Stephen Ulamac, DLR, Köln Proz-Wahn, Germany;
Denis Moura, CNES, Toulouse, France; and
R. Mugnuolo, Italian Space Agency, Matera, Italy.
The following are the instruments on Philae.
APXS (Alpha Particle X-ray Spectrometer) will help infer the atomic composition of the cometary surface minerals.
Principal Investigator: Rudolf Rieder, Max Planck Institut für Chemie, Mainz, Germany.
CIVA is a set of six identical micro-cameras that will take panoramic pictures of the cometary surface.
Principal Investigator: Jean-Pierre Bibring of the Institut d'Astrophysique Spatiale, University of Paris, France.
CONSERT (COmet Nucleus Sounding Experiment by Radiowave Transmission) in the lander will receive the transmissions from the CONSERT instrument on the orbiter.
Principal Investigator: Wlodek Kofman of the Laboratoire de Planetologie, Grenoble.
COSAC (COmetary Sampling And Composition experiment) is a gas analyzer that will identify the organic molecules emanating from the comet.
Principal Investigator: Helmut Rosenbauer of the Max-Planck Institut für Aeronomie, Lindau, Germany.
MODULUS PTOLEMY is a gas analyzer that will provide isotopic ratios of light elements.
Principal Investigator: Ian Wright, Open University, Milton Keynes, UK is the Principal Investigator.
MUPUS consists of sensors to ascertain the density, and thermal and mechanical properties of the surface.
Principal Investigator: Tilman Spohn, Universität Münster, Germany.
ROLIS (ROsetta Lander Imaging System) is a CCD camera to obtain high- resolution pictures during landing, and panoramic images of areas sampled by other instruments.
Principal Investigator: Stefano Mottola, DLR, Berlin, Germany.
ROMAP (ROsetta lander Magnetometer And PLasma monitor) consists of a magnetometer and a plasma probe to monitor the cometary environment and the impacting solar wind.
Principal Investigator: Hans-Ulrich Auster, Technische Universität, Braunschweig, Germany.
SD2 (Sampling and Distribution device) will drill 20 cm into the cometary surface, collect samples either for microscopic inspection or for sending it to different ovens.
Principal Investigator: Ercol Finzi, Politechnico, Milan, Italy.
SESAME (Surface Electrical, Seismic and Acoustic Monitoring Experiment) will emit and receive sound waves that have traversed the surface.
Principal Investigator: Dietrich Mohlmann, DLR, Cologne, Germany.
The 2nd Rosetta Launch Campaign started formally on 24 October 2003. The status today, 3 November, is that the Alenia AIV team has succesfully mounted the High Gain Antenna (HGA) on the spacecraft and we are ready for the HGA deployment test.
In parallel the Dutch Space solar panel experts are doing everything to ensure that the Rosetta Solar Array's are ready to fly. Both solar arrays are still currently dismounted and they are being inspected on the solar array rig. Once this is finished the arrays are mounted on the spacecraft for the final deployment test.
With the launch of ESA's comet chaser scheduled for February 2004, the Rosetta team has been racing to meet a new challenge - a change of target.
Developed and planned over many
years, the pioneering Rosetta mission is one of the most challenging ever
undertaken in the history of space exploration. In May 2003, however, engineers
were presented with a new challenge when ESA's Science Programme
Committee announced that comet 67P/Churyumov-Gerasimenko would replace
comet 46P/Wirtanen as Rosetta's objective.
Not only were the two comets following different orbits and timetables, but the team from ESA, industry and academia would have to prepare the Rosetta lander for a hazardous descent onto a much larger ice world than originally anticipated.
Rising to the challenge, the team began to study the implications of exploring Churyumov-Gerasimenko and the modifications that might be required to the fragile lander. After months of intensive studies and simulations, engineers are now confident that everything possible has been done to ensure that the spacecraft will successfully complete history's first soft touchdown on a cosmic iceberg.
"Comet Churyumov-Gerasimenko is a much bigger comet than Wirtanen," said Philippe Kletzkine, ESA manager for the Rosetta lander. "It is about four times the diameter and its gravity could be at least 30 times greater. This means that the landing speed will increase from 0.2 - 0.5 metres per second to 0.7 - 1.5 metres per second.
"In the case of Wirtanen, our biggest problem was avoiding a rebound - the spacecraft only had to bounce slightly and the momentum would overcome the weak gravitational hold of the comet.
"Now, we also have to worry about absorbing the shock from a faster landing and the stability of the lander upon touchdown. In the worst case scenario of a 'hard' comet surface, rough terrain and relatively high gravity, it was possible that the lander could topple over. In order to prevent this we decided to modify the landing gear."
The design team wanted to avoid removing the landing gear or the entire lander from the Rosetta orbiter, which is currently at the launch centre in Kourou, French Guiana. They also wanted something, small, light and easy to fit. The answer was a small bracket, known as a tilt limiter, that could be attached to the bottom of the lander.
"By restricting the angle at which the landing gear can flex on touchdown to only 3 - 5 degrees, we improve the damping effect on touchdown and reduce the possibility of a rebound," explained Jean-Christophe Salvignol, Rosetta lander mechanical engineer.
"The limiter was designed by Astrium GmbH in collaboration with ourselves and the Max-Planck-Institute in Lindau. During pendulum tests with a model of the landing gear, we simulated landing on a wall at different angles of approach, and verified that the spacecraft could successfully touch down at speeds of up to 1.5 metres per second on a 10 degree slope, or up to 1.2 metres per second on a 30 degree slope.
"In parallel, computerised simulations of landings were run by the Max-Planck-Institute to better determine the landing performances for various surface characteristics, impact velocities and lander attitudes."
The tilt limiter was finally delivered to Kourou and mounted on the spacecraft landing gear on 30 September.
"This excellent collaboration between ESA, industry and MPAe has enabled us to adapt to the new mission very quickly and efficiently," said Salvignol.
No major changes are envisaged for the lander's descent profile. However, under the new mission scenario, there will be more time available for the orbiter's instruments to map the nucleus in detail and find a safe haven for the 100 kg lander.
The historic touchdown on the pristine surface of comet Churyumov-Gerasimenko is expected to take place in November 2014. "We anticipate a landing on the 'summer' side of the nucleus, where there is maximum illumination," said Philippe Kletzkine.
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