PDS_VERSION_ID                = PDS3
LABEL_REVISION_NOTE           = "20170317 R. Lorenz"
RECORD_TYPE                   = STREAM

OBJECT                        = INSTRUMENT
 INSTRUMENT_HOST_ID           = VEGA2
 INSTRUMENT_ID                = "VG2LR"

 OBJECT                       = INSTRUMENT_INFORMATION
  INSTRUMENT_NAME             = "VEGA2 LANDER METEO"
  INSTRUMENT_TYPE             = "METEOROLOGY"
  INSTRUMENT_DESC             = "

Instrument Overview
===================

The details of the implementation of the atmospheric structure investigation
('METEO') on the Vega landers are described in LINKIN1986A and LINKIN1987.
In fact, no results from the Vega-1 lander has been reported.  The tabulated
Vega-2 results give a profile of measurements from an altitude of 63km down
to the surface (reached about 1 hour and 1 minute later) and for about 1
minute thereafter.

Science Objectives
==================

The investigation was to measure atmospheric temperature and pressure during
the descent, to make a profile of the atmospheric structure and stability.
The instrumentation and the comparatively high data rate afforded by radio
relay via the Vega flyby spacecraft allowed a much higher-resolution profile
to be obtained than was possible with previous Venera landers.

METEO Detailed Description
=======================

As is typical given the wide dynamic range of pressures encountered in Venus
atmospheric descent (tens to hundreds of millibar at the end of entry,
roughly at the cloudtops or 65km altitude) to the surface at about 90 bar,
the pressure sensing was implemented by three sensors with overlapping ranges
(0-2, 0-20 and 2-110 bar).  In fact only the latter was mounted inside the
large, well-insulated lander ; the first two operated in benign enough
conditions that an external box proofed to 30 bar was adequate for their
housing.

Two temperature sensors were used during descent, one a bare platinum wire
(similar to those flown on Pioneer Venus), the other mounted inside a
ceramic shield to protect against acid droplets - [LINKIN1987] notes the
failure of the Pioneer Venus sensors below 12km altitude.

The two different sensors with different thermal inertias allowed the
possibility of isolating short-term ambient temperature variations.

Two additional temperature sensors, using nickel films on a glass substrate,
gave data in the earliest parts of descent, but appear to have failed when a
pyro to separate the entry shell was fired.

Principal Investigator
======================

The principal investigator for the Vega lander METEO experiment was
Slava Linkin of the Space Research Institute IKI in Moscow."

 END_OBJECT                   = INSTRUMENT_INFORMATION

 OBJECT                       = INSTRUMENT_REFERENCE_INFO
  REFERENCE_KEY_ID            = "LINKIN1986A"
 END_OBJECT                   = INSTRUMENT_REFERENCE_INFO

 OBJECT                       = INSTRUMENT_REFERENCE_INFO
  REFERENCE_KEY_ID            = "LINKIN1987"
 END_OBJECT                   = INSTRUMENT_REFERENCE_INFO

END_OBJECT                    = INSTRUMENT
END