Using speed of sound measurements to constrain the Huygens probe descent profile

Details Using speed of sound measurements to constrain the Huygens probe descent profile Using speed of sound measurements to constrain the Huygens probe descent profile

Feb 2004

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004esasp.544..221s&link_type=abstract

In: Proceedings of the International Workshop Planetary Probe Atmospheric Entry and Descent Trajectory Analysis and Science, 6-9

Computer Science

Sound

1

Entry Probes, Titan, Huygens

Scientific paper

The Acoustic Properties Investigation (API) is a set of sensors for acoustic measurements in gases or liquids, making a part of the Surface Science Package (SSP) on the Huygens probe. It consists of two units, API-V (Velocity of sound) and API-S (Sounding). The API-V has two ultrasonic transducers sending and receiving acoustic pulses over an unobstructed path of 15 cm. An accurate timing circuit is measuring the time it takes to propagate over the distance. Measurements are made in both directions to eliminate the effect of a constant drift of the medium. The transducers have been optimised to operate at low pressure (high altitude) and will operate from about 60 km down to the surface. They will also perform well in case of landing in a liquid. The API-S unit is an acoustic sounder, sending short pulses at 15 kHz every second and listening for echoes in between. It will detect droplets in the atmosphere and for the last 100 m it will characterise the acoustic scattering properties of the surface below. It will also give an accurate value for the descend velocity during the last 100 m. In case of landing in a (liquid) lake/ocean it will measure the depth of the late-ocean down to a maximum of about 1000 m. Accurate measurements of the velocity of sound will, together with knowledge on the temperature, enable the mean molecular weight to be calculated along the descent trajectory. The temperature will be measured by complementary sensors inside the SSP Top Hat, near the API-V, and to a high accuracy by the HASI instrument at the periphery of the Huygens probe. The API units and associated electronics has been designed and build at the Research and Scientific Support Department at ESTEC, where also the testing and initial calibration has been done. Detailed calibration has been performed with different gas mixtures and at different temperatures in the Titan simulation chamber at the University of Kent, Canterbury, UK. Further supporting studies are planned in the new Titan simulation chamber at the Open University, Milton Keynes, UK. This paper discusses the hardware, the modes of operation, the calibration and the expected performances, including error sources, measurement accuracy and range of operation.

Affiliated with

Also associated with

No associations

Rating

Using speed of sound measurements to constrain the Huygens probe descent profile does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Using speed of sound measurements to constrain the Huygens probe descent profile, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Using speed of sound measurements to constrain the Huygens probe descent profile will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1018892