In February 2000, after the fifth in-flight cruise check-out of the Huygens Probe, a dedicated Probe Relay Link Test was performed, aimed at characterising the performance of the Probe Support Equipment (PSE) under realistic mission conditions. This test revealed some unexplained anomalies in the communication subsystem in terms of data recovery in the presence of Doppler at mission-representative levels.

An Investigation Team was therefore established in Spring 2000, with the participation of ESA, NASA/JPL and industry representatives, to investigate this matter further and assess its potential impact on the Huygens mission. Ground tests conducted at ESOC on the Huygens reference model (engineering and spare models) confirmed the non-optimal behaviour of the communication subsystem, which would have an adverse impact on data recovery during the Probe’s descent at Titan.

The ESA Director General subsequently convened an independent Enquiry Board charged with:

  • assessing the current status of the Huygens communication link
  • recommending a course of action to be followed to safeguard the mission objectives and guarantee full scientific data return
  • providing recommendations to ensure that such problems will not occur on future projects

Board members held interviews and hearings with ESA, NASA and Industry project staff and experts. Today, 20 December 2000, the Board presented their findings, recommendations and conclusions.

  • Huygens communications link enquiry board report [Word]
  • Huygens communications link enquiry board – annex [Acrobat] [Powerpoint]