Question: When was the launch of the seventh spacecraft bearing the name of the planet where Samara Valles is found?

full_context: Document 1: Mars 2M No.522: Mars 2M No.522 was launched at 10:33:00 UTC on 2 April 1969 atop a Proton-K 8K78K carrier rocket with a Blok D upper stage, flying from Baikonur Cosmodrome Site 81/24. One of the first stage engines caught fire almost immediately at liftoff. The remaining engines managed to compensate for about 30 seconds of flight, but the thrust section fire eventually resulted in loss of control. The Proton pitched over and began flying horizontally before ground controllers sent a manual shutoff command. The vehicle nosedived into the ground just outside the launch complex 41 seconds after launch. Subsequent examination found that a missing drain plug allowed nitrogen tetroxide to leak out and start a fire.
Document 2: Vedra Valles: Vedra Valles is an ancient river valley in the Lunae Palus quadrangle of Mars, located at 19.4° N and 55.6° W. It is 115.0 km long and was named after an ancient river in Great Britain.
Document 3: Kosmos 176: A Kosmos-2I 63SM carrier rocket was used to launch Kosmos 176 from Site 133/1 at Plesetsk Cosmodrome. The launch occurred at 17:00 UTC on 12 September 1967, and resulted in Kosmos 176's successful deployment into Low earth orbit.
Document 4: Sabis Vallis: Sabis Vallis is an ancient river valley in the Memnonia quadrangle of Mars, located at 5.3° south latitude and 152.5° west longitude. It is 206 km long and was named after a classical name for the present Sambre River in France and Belgium.
Document 5: Foton-M No.4: Foton-M No.4 was launched from the Baikonur Cosmodrome on 18 July 2014, atop a Soyuz-2-1a carrier rocket. The launch was completed successfully, with the satellite separating from its rocket and beginning data transmission to its controllers. However, after four orbits, it ceased responding to commands issued to it from the ground. As a consequence of this, the spacecraft did not perform an orbit-raising maneuver that had been scheduled to occur shortly after orbital insertion. Satellite control was regained on 26 July by which time some of the microgravity experiments had already begun. On 1 August the head of Roskosmos, Oleg Ostapenko, was quoted as saying that the satellite will fly its entire two-month mission as originally planned, despite the cancellation of the orbit-boosting maneuver. However, all of the experiments completed by 27 August, and the Russian space agency decided to return the spacecraft to Earth on 1 September, two weeks earlier than the original 15 September target landing date.
Document 6: Kosmos 173: A Kosmos-2I 63SM carrier rocket was used to launch Kosmos 173 from Site 133/1 at Plesetsk Cosmodrome. The launch occurred at 04:59:49 UTC on 24 August 1967, and resulted in Kosmos 173's successful deployment into low earth orbit.
Document 7: Mars Orbiter Mission: The Mars Orbiter Mission probe lifted - off from the First Launch Pad at Satish Dhawan Space Centre (Sriharikota Range SHAR), Andhra Pradesh, using a Polar Satellite Launch Vehicle (PSLV) rocket C25 at 09: 08 UTC on 5 November 2013. The launch window was approximately 20 days long and started on 28 October 2013. The MOM probe spent about a month in Earth orbit, where it made a series of seven apogee - raising orbital manoeuvres before trans - Mars injection on 30 November 2013 (UTC). After a 298 - day transit to Mars, it was successfully inserted into Mars orbit on 24 September 2014.
Document 8: Samara Valles: Samara Valles is a valley bordering the Memnonia quadrangle and the Margaritifer Sinus quadrangle on Mars, located at approximately 25.1° south latitude and 19.1° west longitude. It is 615 km long and was named after the ancient name for modern Somme River, France.
Document 9: Maumee Valles: Maumee Valles is an ancient river valley in the Lunae Palus quadrangle of Mars, located at 19.7° N and 53.2° W. It is 350.0 km long and was named after a North American river in Indiana and Ohio.
Document 10: Mars 7: Mars 7 was launched by a Proton-K carrier rocket with a Blok D upper stage, flying from Baikonur Cosmodrome Site 81/24. The launch occurred at 17:00:17 UTC on 9 August 1973, with the first three stages placing the spacecraft and upper stage into a low Earth parking orbit before the Blok D fired to propel Mars 7 into heliocentric orbit bound for Mars. The spacecraft performed a course correction on 16 August 1973.
Document 11: Stura Vallis: Stura Vallis is an ancient river valley in the Elysium quadrangle of Mars, located at 22.9° north latitude and 217.6° west longitude. It is 75 km long and was named after a classical river east of Rome, Italy.
Document 12: Warrego Valles: Warrego Valles is an ancient river valley in the Thaumasia quadrangle of Mars, located at 42.2° south latitude and 93° west longitude. It is 188 km
Document 13: Paraná Valles: Paraná Valles is a valley in the Margaritifer Sinus quadrangle (MC-19) region of Mars, located at approximately 23.1° South and 10.2° West. It is 350 km long and was named after an ancient and modern name for a South American river (Brazil, Argentina). A low area between Paraná Valles and Loire Valles is believed to have once held a lake.
Document 14: Simud Valles: Simud Valles is an ancient outflow channel in the Oxia Palus quadrangle of Mars, located at 19.8° N and 37.8° W. It is 945.0 km long and was named for the word for "Mars" in Sumerian. Note: Descriptor term changed to the plural (valles), and coordinates redefined 3/31/2008.
Document 15: Space Race: In 1953, Korolev was given the go-ahead to develop the R-7 Semyorka rocket, which represented a major advance from the German design. Although some of its components (notably boosters) still resembled the German G-4, the new rocket incorporated staged design, a completely new control system, and a new fuel. It was successfully tested on August 21, 1957 and became the world's first fully operational ICBM the following month. It would later be used to launch the first satellite into space, and derivatives would launch all piloted Soviet spacecraft.
ground_truth: 9 August 1973
sub_queries: Where is Samara Valles found? Answer: Mars
What day was Mars 7 launched? Answer: 9 August 1973