Venera 13 (Венера-13) was a probe in the Soviet Venera program for the exploration of Venus.

Venera 13 and 14 were identical spacecraft built to take advantage of the 1981 Venus launch opportunity and launched 5 days apart, Venera 13 on 1981-10-30 at 06:04:00 UTC and Venera 14 on 1981-11-04 at 05:31:00 UTC, both with an on-orbit dry mass of 760 kg.

Design

Each mission consisted of a bus and an attached descent craft. The descent craft/lander was a hermetically sealed pressure vessel, which contained most of the instrumentation and electronics, mounted on a ring-shaped landing platform and topped by an antenna. The design was similar to the earlier Venera 9–12 landers. It carried instruments to take chemical and isotopic measurements, monitor the spectrum of scattered sunlight, and record electric discharges during its descent phase through the Venusian atmosphere. The spacecraft utilized a camera system, an X-ray fluorescence spectrometer, a screw drill and surface sampler, a dynamic penetrometer, and a seismometer to conduct investigations on the surface.

List of lander experiments and instruments:

• Accelerometer, Impact Analysis - Bison-M
• Thermometers, Barometers - ITD
• Spectrometer / Directional Photometer - IOAV-2
• Ultraviolet Photometer
• Mass Spectrometer - MKh-6411
• Penetrometer / Soil Ohmmeter - Prop-V
• Chemical Redox Indicator - Kontrast
• 2 Color Telephotometer Cameras - TFZL-077
• Gas Chromatograph - Sigma-2
• Radio / Seismometer - Groza-2
• Nephelometer - MNV-78-2
• Hydrometer - VM-3R
• X-Ray Fluorescence Spectrometer (Aerosol) - Bora-1
• X-Ray Fluorescence Spectrometer (Soil) - Arakhis-2
• Soil Drilling Apparatus - GZU
• Stabilized Oscillator / Doppler Radio

Landing

After launch and a four month cruise to Venus the descent vehicle separated from the bus and plunged into the Venusian atmosphere on March 1, 1982. After entering the atmosphere a parachute was deployed. At an altitude of about 50 km the parachute was released and simple airbraking was used the rest of the way to the surface.

Venera 13 landed at , about 950 km northeast of Venera 14, just east of the eastern extension of an elevated region known as Phoebe Regio.

The lander had cameras to take pictures of the ground and spring-loaded arms to measure the compressibility of the soil. The quartz camera windows were covered by lens caps which popped off after descent.

The area was composed of bedrock outcrops surrounded by dark, fine-grained soil. After landing an imaging panorama was started and a mechanical drilling arm reached to the surface and obtained a sample, which was deposited in a hermetically sealed chamber, maintained at 30 °C and a pressure of about 0.05 atmosphere (5 kPa). The composition of the sample determined by the X-ray fluorescence spectrometer put it in the class of weakly differentiated melanocratic alkaline gabbroids.

The lander survived for 127 minutes (the planned design life was 32 minutes) in an environment with a temperature of 457 °C (855 °F) and a pressure of 89 Earth atmospheres (8.9 MPa). The descent vehicle transmitted data to the bus, which acted as a data relay as it flew by Venus. The probe probably still rests on the surface as of today.

Image processing

American researcher Don P. Mitchell has processed the color images from Venera 13 and 14 using the raw original data. This representation is what the surface would look like in Earth sunlight, without the orange haze of Venus' thick atmosphere. The new images are based on a more accurate linearization of the original 9-bit logarithmic pixel encoding.

References