:PrOP-M

{{Infobox spaceflight

| name = PrOP-M

| image = PrOP-M.jpg

| image_caption = Rendering of the PrOP-M

| insignia =

| insignia_caption =

| mission_type = Mars rover

| operator = Soviet Space Program

| website =

| mission_duration =

| manufacturer = Mobile Vehicle Engineering Institute

| launch_date = 1971

}}

PrOP-M ({{langx|ru|Прибор оценки проходимости — Марс (ПрОП-М)}}, Passability Estimating Vehicle for Mars or Device Evaluation Terrain—Mars{{cite web |last1=Ackerman |first1=Evan |title=Meet the Very First Rover to Land on Mars |url=https://spectrum.ieee.org/meet-the-very-first-rover-to-land-on-mars |website=IEEE |access-date=28 October 2021}}) were two Soviet Mars rovers that were launched on the unsuccessful Mars 2 and Mars 3 missions in 1971. PrOP-M were the first rovers to be launched to Mars, 26 years before the first successful rover mission of NASA's Sojourner in 1997. Because the Mars 2 and Mars 3 missions failed, the existence of the rovers was kept secret for nearly 20 years.

The rovers, built by a team led by Alexander Kemurdzhian, were small, rectangular devices that were tethered to the lander and used skis for movement.

History

File:PrOP-M on the manipulator.jpg

File:PrOP-M moving on skis.gif

File:FP2A3620 (23497688248) (cropped).jpg in Moscow. PrOP-M is seen on top.]]

The PrOP-M rover was designed and manufactured at the Mobile Vehicle Engineering Institute (VNIITransmash) by a team of approximately 150 engineers led by Alexander Kemurdzhian, who also developed the Lunokhod rover.

The Mars 2 and Mars 3 landers each carried a PrOP-M rover, designed to move across the Martian surface on skis while connected to the lander with a {{Convert|15|meter|ft|abbr=out|adj=on}}-long power cable. Two small metal rods were used for autonomous obstacle avoidance because radio signals from Earth would have taken too long to drive the rovers using remote control. Each rover carried a dynamic penetrometer (made by Transmash) and a gamma-ray densitometer (made by the Institute of Geochemistry of the Soviet Academy of Sciences).{{cite book|last=Perminov|first=V.G.|title=The Difficult Road to Mars - A Brief History of Mars Exploration in the Soviet Union|date=July 1999|publisher=NASA Headquarters History Division|isbn=0-16-058859-6|pages=[https://archive.org/details/difficultroadtom00perm/page/34 34–60]|url=https://archive.org/details/difficultroadtom00perm/page/34}} After landing, the rovers were planned to be placed on the Martian surface by a 6-joint manipulator arm and to move in the field of view of the lander's cameras. They would have stopped to make measurements every {{Convert|1.5|meters|ft|abbr=on}}, with maximum range of {{Convert|15|meters|ft|abbr=on}}—the length of the tether. The rovers' tracks in the Martian soil would have been used to determine the soil's material properties.

The rovers' main chassis was a {{convert|4.5|kg|lb|abbr=out|adj=on}} square box with a small protrusion at the center. Sources differ on the dimensions of the rover.{{efn|Sources give the following numbers:
{{Convert|25|x|22|x|4|cm|abbr=on}},{{cite web |title=Марс-3 |url=https://epizodyspace.ru/01/2u/solnthe/ams/m-3/m-3.html |website=epizodyspace.ru |access-date=28 October 2021}}
{{Convert|25|x|25|x|4|cm|abbr=on}},{{cite book |last1=Huntress |first1=Wesley T. |title=Soviet robots in the solar system : mission technologies and discoveries |date=2011 |publisher=Springer |location=New York |isbn=978-1441978974 |page=256}}
{{Convert|21.5|x|16|x|6|cm|abbr=on}},{{cite book |last1=Ulivi |first1=Paolo |title=Robotic exploration of the solar system |date=2007 |publisher=Springer |location=Berlin |isbn=978-0387493268 |page=105}}{{cite book |last1=Gao |first1=Yang |title=Contemporary Planetary Robotics: An Approach Toward Autonomous Systems |date=13 September 2016 |publisher=John Wiley & Sons |location=Weinheim, Germany |isbn=978-3-527-41325-6 |page=33 |url=https://books.google.com/books?id=D5tPCwAAQBAJ&dq=prop-m+rover&pg=PA33 |access-date=17 January 2022 |language=en}}
{{Convert|25|x|20|x|4|cm|abbr=on}}{{cite book |last1=Harvey |first1=Brian |title=Russian space probes : scientific discoveries and future missions |date=2011 |publisher=Springer |location=New York |isbn=9781441981509 |page=270 |url=https://books.google.com/books?id=q6qyVkapjeoC&q=prop-m%20rover |access-date=18 January 2022}}}} The frame was supported on two wide, flat skis, one extending from each side, elevating the frame slightly above the surface. At the front of the box were obstacle detection bars. Rover's maximum speed was up to 1 meter per hour.{{cite book |last1=Truszkowski |first1=Walt |last2=Rouff |first2=Christopher |last3=Akhavannik |first3=Mohammad |last4=Tunstel |first4=Edward |title=Robot Memetics: A Space Exploration Perspective |date=30 January 2020 |publisher=Springer Nature |isbn=978-3-030-37952-0 |page=7 |url=https://books.google.com/books?id=FG_NDwAAQBAJ&dq=prop-m+rover&pg=PA7 |access-date=17 January 2022 |language=en}} PrOP-M was the only rover that used skis for locomotion, all other rovers used wheels.{{cite book |last1=Ellery |first1=Alex |title=Planetary rovers : robotic exploration of the solar system |date=2016 |location=Berlin |isbn=9783642032592 |page=59}}

The rover had a algorithm to overcome obstacles: when it approached one, it was programmed to reverse and "use the skids on alternate sides to walk around the obstacle".{{cite book |last1=Harvey |first1=Brian |title=Russian Planetary Exploration: History, Development, Legacy and Prospects |date=2007 |publisher=Springer Science & Business Media |isbn=9780387496641 |page=[https://books.google.com/books?id=jKmIclMIwPAC&dq=prop-m+rover+alexander+%5E&pg=PA134 134]|author-link=Brian Harvey (author)}}

The first rover was destroyed in the November 27, 1971 crash landing of Mars 2, launched May 19, 1971.

{{Cite web|title=Mars 2 Lander|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1971-045D|access-date=7 November 2021|website=NASA Space Science Data Coordinated Archive|publisher=NASA|id=NSSDCA/COSPAR ID: 1971-045D}} The second one was launched on May 28, 1971 on Mars 3 and was lost when the lander stopped communicating 110 seconds after landing on December 2, 1971.{{cite web|title=Mars 3 Lander|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1971-049F|access-date=7 November 2021|website=NASA Space Science Data Coordinated Archive|publisher=NASA|id=NSSDCA/COSPAR ID: 1971-049F}} The loss of communication may have been due to the extremely powerful Martian dust storm taking place at the time or a problem with the Mars 3 orbiter's ability to relay communications. The second rover was never deployed. The rover missions were secret and were not mentioned in official news reports about the landings; their existence was revealed almost 20 years later in 1990.{{cite web |last1=Anderson |first1=Charlene |title=The First Rover on Mars - The Soviets Did It in 1971 |url=https://www.planetary.org/articles/tpr_1990_4_anderson |publisher=Planetary Society |access-date=28 October 2021}} The PrOP-M rovers preceded NASA's 1997 Sojourner by 26 years.{{Cite book |last=Bard |first=Jonathan |date=2020 |title=Destination Mars |publisher=Gareth Stevens Pub

|url=https://books.google.com/books?id=tUImEAAAQBAJ&dq=rover+26+years+earlier+than+sojourner&pg=PA15 |isbn=9781538258736 |page=15 }} Authors of the Planetary Landers and Entry Probes wrote that Mars 6 and Mars 7 also carried PrOP-M rovers.{{cite book |last1=Ball |first1=Andrew |last2=Garry |first2=James |last3=Lorenz |first3=Ralph |last4=Kerzhanovich |first4=Viktor |title=Planetary Landers and Entry Probes |date=10 May 2007 |publisher=Cambridge University Press |isbn=978-1-139-46161-0 |page=127 |url=https://books.google.com/books?id=cyehD1KsTKoC&dq=prop-m+rover&pg=PA127 |access-date=17 January 2022 |language=en}}

A model of the rover can now be seen in the Memorial Museum of Cosmonautics in Moscow, another is in the Museum of Space and Missile Technology in Saint Petersburg.{{cite news|url=https://www.spbmuseum.ru/exhibits_and_exhibitions/93/49128/?sphrase_id=45363|title=Первая колея на Луне. Выставка приурочена к юбилею конструктора планетоходов Александра Кемурджяна|trans-title=The first track on the moon. The exhibition is timed to the anniversary of the designer of planetary rovers Alexander Kemurdzhian|work=www.spbmuseum.ru|access-date=24 November 2021}}

Notes

References

External links

Soviet films about Mars exploration, featuring PrOP-M rover
[https://www.youtube.com/watch?v=tVJfjDOa3TI Mars 2 and Mars 3]
[https://www.youtube.com/watch?v=nF2gU3_9WC4 From Moonrover to Marsrover]
[https://www.spb.kp.ru/daily/26980/4039317/ Found 42 years later: How Leningrad scientists created the world's first rover.] (Russian: Нашли спустя 42 года: Как ленинградские ученые первый в мире марсоход создавали.)

Category:Mars rovers

Category:Space program of the Soviet Union

Category:Spacecraft launched in 1971

Category:1971 on Mars

Category:Robots of the Soviet Union