THE SOCIET VENERA 5 SPACE PROBE IS LAUNCHED IN 1969

Today, The Grandma has been reading about Venera 5, the Soviet space probe that was launched on a day like today in 1969.

Venera 5, in Russian Венера-5 meaning Venus 5, was a space probe in the Soviet space program Venera for the exploration of Venus.

Venera 5 was launched towards Venus to obtain atmospheric data. The spacecraft was very similar to Venera 4 although it was of a stronger design. The launch was conducted using a Molniya-M rocket, flying from the Baikonur Cosmodrome.

When the atmosphere of Venus was approached, a capsule weighing 405 kg and containing scientific instruments was jettisoned from the main spacecraft. During satellite descent towards the surface of Venus, a parachute opened to slow the rate of descent. For 53 minutes on 16 May 1969, while the capsule was suspended from the parachute, data from the Venusian atmosphere were returned.

It landed at 3°S 18°E. The spacecraft also carried a medallion bearing the State Coat of Arms of the Soviet Union and a bas-relief of Lenin to the night side of Venus.

Given the results from Venera 4, the Venera 5 and Venera 6 landers contained new chemical analysis experiments tuned to provide more precise measurements of the atmosphere's components. Knowing the atmosphere was extremely dense, the parachutes were also made smaller so the capsule would reach its full crush depth before running out of power as Venera 4 had done.

Venera 5 was launched into an Earth parking orbit on 5 January 1969 at 06:28:08 UTC and then from a Tyazheliy Sputnik (69-001C) towards Venus. After a mid-course maneuver on 14 March 1969, the probe was released from the bus on 16 May 1969 at a distance of 37,000 km from Venus. The probe entered the nightside atmosphere at 06:01 UTC and when the velocity slowed to 210 m/s the parachute deployed and transmissions to Earth began. The probe sent read-outs every 45 seconds for 53 minutes before finally succumbing to the temperature and pressure at roughly 320 °C and 2,610 kilopascals.

The photometer detected a light level of 250 watts per square meter and confirmed the high temperatures, pressures, and carbon dioxide composition of the atmosphere found by Venera 4.

More information: NASA

Anyone who has spent any time in space
will love it for the rest of their lives.
I achieved my childhood dream of the sky.

Valentina Tereshkova

VENERE 7, THE SUCCESSFUL RUSSIAN LANDING ON VENUS

Today, The Grandma has received the wonderful visit of one of her closest friends, Joseph de Ca'th Lon.

Joseph likes Astronomy, History and Archaeology. They have been talking about Venera 7, the Soviet spacecraft, part of the Venera series of probes to Venus, that landed on the Venusian surface on a day like today in 1970.

Venera 7 (in Russian Венера-7 meaning Venus 7) was a Soviet spacecraft, part of the Venera series of probes to Venus. When it landed on the Venusian surface on 15 December 1970, it became the first spacecraft to soft land on another planet and the first to transmit data from there back to Earth.

The lander was designed to be able to survive pressure of up to 180 bars and temperatures of 580 °C. This was significantly greater than what was expected to be encountered but significant uncertainties as to the surface temperatures and pressure of Venus resulted in the designers' opting for a large margin of error. The degree of hardening added mass to the probe which limited the amount of mass available for scientific instruments both on the probe itself and the interplanetary bus.

The interplanetary bus carried a solar wind charged particle detector and a cosmic ray detector. On the lander there were temperature and pressure sensors as well as an accelerometer to measure atmospheric density. The probe also carried a radar altimeter.

The probe was launched from Earth on 17 August 1970, at 05:38 UTC. It consisted of an interplanetary bus, based on the 3MV system, and a lander. During the flight to Venus, two in-course corrections were made using the bus' on-board KDU-414 engine.

Venera 7 entered the atmosphere of Venus on 15 December 1970. The lander remained attached to the interplanetary bus during the initial stages of atmospheric entry, to allow the bus to cool the lander to −8 °C for as long as possible.

More information: Russian Space Web

The lander was ejected once atmospheric buffeting broke the interplanetary bus's lock-on with Earth. The parachute opened at a height of 60 km, and atmospheric testing began with results showing the atmosphere to be 97% carbon dioxide. The parachute was initially reefed down to 1.8 square meters, opening to 2.5 square meters 13 minutes later, when the reefing line melted as designed. Six minutes after the unreefing, the parachute started to fail, resulting in a descent more rapid than planned.

The parachute eventually failed completely, and the probe entered a period of freefall. As a result, the lander struck the surface of Venus at about 59 km/h at 05:37:10 UTC.

The probe appeared to go silent on impact, but recording tapes kept rolling. A few weeks later, upon a review of the tapes by the radio astronomer Oleg Rzhiga, another 23 minutes of very weak signals were found on them. The spacecraft had landed on Venus, and probably bounced onto its side, leaving the medium gain antenna not aimed correctly for strong signal transmission to Earth.

The probe transmitted information to Earth for 53 minutes, which included about 20 minutes from the surface. It was found that the temperature at the surface of Venus was 475 °C ± 20 °C. Using the temperature, and models of the atmosphere, a pressure of 9.0 MPa ± 1.5 MPa was calculated.

From the spacecraft's rapid halt, from falling to stationary inside 0.2 seconds, it was possible to conclude that the craft had hit a solid surface with low levels of dust.

The probe provided information about the surface of Venus, which could not be seen through a thick veil of atmosphere. The spacecraft definitively confirmed that humans cannot survive on the surface of Venus, and excluded the possibility that there is any liquid water on Venus.

More information: New Atlas

 There is good evidence that Venus once had
liquid water and a much thinner atmosphere,
similar to Earth billions of years ago.
But today the surface of Venus is dry as a bone,
hot enough to melt lead,
there are clouds of sulfuric acid that reach
a hundred miles high and the air is so thick
it's like being 900 meters deep in the ocean.

Bill Nye

THE CASSINI-HUYGENS LAST MISSION IN SPACE

The Cassini–Huygens

The Cassini–Huygens mission was a collaboration between NASA, the European Space Agency (ESA), and the Italian Space Agency (ASI) to send a probe to study the planet Saturn and its system, including its rings and natural satellites. The Flagship-class unmanned robotic spacecraft comprised both NASA's Cassini probe, and ESA's Huygens lander which would be landed on Saturn's largest moon, Titan. Cassini was the fourth space probe to visit Saturn and the first to enter its orbit. The craft were named after astronomers Giovanni Cassini and Christiaan Huygens.

Launched aboard a Titan IVB/Centaur on October 15, 1997, Cassini was active in space for more than 18 years, with 13 years spent orbiting Saturn, studying the planet and its system after entering orbit on July 1, 2004. The voyage to Saturn included flybys of Venus, Earth , the asteroid 2685 Masursky, and Jupiter. 

Its mission ended on September 15, 2017, when Cassini was commanded to fly into Saturn's upper atmosphere and burn up, in order to prevent any risk of contaminating Saturn's moons, some of whose environments could potentially bear life, with stowaway terrestrial microbes. 

The Cassini–Huygens

The mission is widely perceived to have been successful beyond expectation. Cassini-Huygens has been described by NASA's Planetary Science Division Director as a mission of firsts, that has revolutionized human understanding of the Saturn system, including its moons and rings, and our understanding of where life might be found in the Solar System.

Cassini's original mission was planned to last for four years, from June 2004 to May 2008. The mission was extended for another two years until September 2010, branded the Cassini Equinox Mission. The mission was extended a second and final time with the Cassini Solstice Mission, lasting another seven years until September 15, 2017, on which date Cassini was de-orbited by being allowed to burn up in Saturn's upper atmosphere.

More information: NASA

The Huygens module traveled with Cassini until its separation from the probe on December 25, 2004; it was successfully landed by parachute on Titan on January 14, 2005. It successfully returned data to Earth for around 90 minutes, using the orbiter as a relay. This was the first landing ever accomplished in the outer Solar System and the first landing on a moon other than our own. Cassini continued to study the Saturn system in the following years.

Landed on Saturn's largest moon Titan

At the end of its mission, the Cassini spacecraft executed the Grand Finale of its mission: a number of risky passes through the gaps between Saturn and Saturn's inner rings. 

The purpose of this phase was to maximize Cassini's scientific outcome before the spacecraft was destroyed. The atmospheric entry of Cassini effectively ended the mission, although data analysis and production will continue afterwards.

Until September 2017 the Cassini probe continued orbiting Saturn at a distance of between 8.2 and 10.2 astronomical units from the Earth. It took 68 to 84 minutes for radio signals to travel from Earth to the spacecraft, and vice versa. Thus ground controllers could not give real-time instructions for daily operations or for unexpected events. Even if response were immediate, more than two hours would have passed between the occurrence of a problem and the reception of the engineers' response by the satellite.

More information: Cassini-The Grand Finale

We must believe then, that as from hence we see Saturn and Jupiter; 

if we were in either of the Two, 

we should discover a great many Worlds which we perceive not; 

and that the Universe extends so in infinitum.
 

Cyrano de Bergerac