NASA Logo, National Aeronautics and Space Administration
NASA Space Science Data Coordinated Archive Header

Comet Nucleus Sounding Experiment by Radio Wave Transmission (CONSERT)

NSSDCA ID: 2004-006A-05

Mission Name: Rosetta
Principal Investigator:Dr. Wlodek Kofman

Description

The Comet Nucleus Sounding Experiment by Radiowave Transmission (CONSERT) is designed to probe the interior of the comet nucleus by making careful measurements of radio sounding pulses transmitted through the comet. This experiment has components on the Rosetta orbiter and the lander. The scientific objectives are to study the mean permittivity of the nucleus to identify electrical properties, identify classes of nucleus material from mean absorption, search for irregularities, small structures, and internal interfaces, and characterize the size of possible cometesimals.

The CONSERT experiment involves a transmitter on the Rosetta orbiter and two perpendicular dipoles 90 degrees out of phase which are fed a coded (pseudo-noise, 255 x 100 nanosecond) radio signal and emit a 90 Mhz circularly polarized 25.5 microsecond duration pulse. The RF power of the transmission from the orbiter is 2 W. Repeated transmissions occur over about 200 milliseconds. The pulses propagate through the comet nucleus and are received by a transponder on the Rosetta lander, where they are digitized and compressed. After a known measured delay corresponding to the propogation of the signal through the strongest path, the lander transponder re-emits a new pulse at 0.2 W RF power, which travels back through the nucleus and is detected by a linear phase 86 to 94 MHz receiver on the orbiter. The time for one session is less than one second. Compilation of thousands of these sessions (~6000/orbit) will allow radio tomography of the interior of the nucleus and give information on electrical properties of the comet. The antenna and ground plane elements are made of aluminum rods with a carbon fiber mast. The antenna on the lander will consist of four metallic wire monopoles mounted so they will be within 40 cm of the surface of the comet to ensure good coupling with the ground.

Alternate Names

  • CONSERT
  • Rosetta/CONSERT

Funding Agency

  • European Space Agency (International)

Discipline

  • Planetary Science: Small Bodies

Additional Information

Questions and comments about this experiment can be directed to: Dr. David R. Williams

 

Personnel

NameRoleOriginal AffiliationE-mail
Dr. Wlodek KofmanPrincipal InvestigatorCNRS, Centre d'Etude des Phenomenes Aleatoires et Geophysiqueswlodek.kofman@obs.ujf-grenoble.fr

Selected References

  • Kofman, W., et al., Comet nucleus sounding experiment by radiowave transmission, Adv. Space Res., 21, No. 11, 1589-1598, doi:10.1016/S0273-1177(97)00952-6, 1998.
  • Kofman, W., et al., The Comet Nucleus Sounding Experiment by Radiowave Transmission (CONSERT): A Short Description of the Instrument and of the Commissioning Stages, Space Sci. Rev., 128, 413-432, doi:10.1007/s11214-006-9034-9, 2007.
[USA.gov] NASA Logo - nasa.gov