Proximity Link UHF Transponder for Small Planetary Landers

Paper number

IAC-05-B3.6.05

Author

Mr. Jeremie Benoist, Centre National d'Etudes Spatiales (CNES), France

Year

2005

Abstract

INTRODUCTION

In the frame of CNES Mars PREMIER (Programme de Retour d’Echantillons Martiens et Installation d’Expériences en Réseau), the Netlander mission aimed to establish the first Martian landers network ever launched. After 9 months cruise carried by MSR orbiter (Mars Sample Return), four identical small stations (25 kg on the surface) would initiate for more than 700 sols the widest scale monitoring ever made on MARS. More than nine experiments and more than fifteen countries wanted to directly contribute to highly enhance our knowledge of the planet over all its facets : deep internal structure, sub-surface structure, surface mineralogy, atmosphere surface interaction and global circulation, ionosphere. Unfortunately, this CNES Martian program was withdrawn in 2003.

The development of the Netlander telecom system (transponder and antenna) was under CNES responsibility. Transponder initial studies began in 1998 and led to the start of the design in 2001. The UHF transponder called SMarT (Small Martian Transponder) has been designed by ELTA under CNES contract for NETLANDER program. A first engineering model (EM) is now tested and delivered.\\

DESIGN GOALS

This equipment shall comply simultaneously with very stringent constraints and a full diversity of applications :

•	TT\&C functions (Telemetry, Telecommand and Tracking via 2-way Doppler measurements),

•	Autonomous beacon EDL (Entry, descent and landing) phase support (Low rate status telemetry and 1-way Doppler),

•	Radioscience experiment (2-way very accurate Doppler measurements),

•	Mass, volume and power consumption requirements (less than 1 kg for entire telecom system and 20 W max instantaneous power),

•	Martian Environment (very high temperature changes, dust),

•	Reliability (dedicated Product Assurance plan).

The paper will describe UHF transponder main features, complying with CCSDS Proximity-1 link standard. This is a very efficient (high sensitivity, very good power efficiency) and highly (programmable) design. This is the reason why this design is well optimized for small planetary lander missions.

Furthermore, in order to reach both electrical and mechanical constraints, an intensive use of COTS parts was made. A dedicated product assurance plan inherited from previous programs was applied in order to guaranty the necessary reliability.\\

CONCLUSION

The present EM show excellent performances that should allow quite efficient TT\&C links for Martian exploration missions and experiments. This is the reason why although Netlander program is today withdrawn, a follow-on funding was obtained by French orbital system R\&D to reach today a 800 g for the transponder (including diplexer).

Thanks to its great integration level and high power efficiency, SMarT would constitute a serious candidate for future Mars and planetary exploration programs and especially for small planetary landers.

Thanks to SMarT digital implementation and to a modular electrical architecture, ELTA could efficiently propose a proximity links package for such programs.

Abstract document

IAC-05-B3.6.05.pdf

Manuscript document

IAC-05-B3.6.05.pdf (🔒 authorized access only).

To get the manuscript, please contact IAF Secretariat.