Interplanetary Robots: True Stories of Space Exploration
“Rod Pyle writes in an accessible style that explains technically complex concepts in easy to understand language.”
Interplanetary Robots provides a look at space robotic missions from the past to the present. “This book is the story of exploration of the solar system” explains author Rod Pyle. Chapter by chapter, the reader will retrace the steps humankind has taken in exploring our solar system and beyond. Pyle writes in an accessible style that explains technically complex concepts in easy to understand language.
Each chapter in Interplanetary Robots is short and describes a particular satellite project or a series of satellite missions. Pyle’s history starts with the V2 rocket program in Nazi Germany where, at the end of WWII, scientist Werner Von Braun escapes to the West with through a secret mission carried out by U.S. Army special agents in a program called Operation Paperclip.
Along with Von Braun and other German scientists, the Americans capture enough hardware to build eighty V2s. The very first American rocket into space, the Vanguard satellite program, was based on V2 technology. The early, pre-NASA, U.S. space missions were run by the Army, Navy, and Air Force, and U.S. space efforts were intended to impress or intimidate the Soviet Union more than they were intended to explore outer space. Space missions used the same type of ballistic missiles to get to orbit as would be used to carry nuclear warheads to start World War III. Not surprisingly there were plans by both Russians and Americans to launch nuclear tipped missiles to explode on the Moon.
The Army Vanguard project failed to reach outer space, and the project was replaced by a Navy program, Explorer. The Russians too had captured German scientists and hardware for their space program, successfully launching the Sputnik satellite to orbit in 1961, beating the U.S. programs into space.
Pyle often returns to the scientists and space missions of NASA’s Jet Propulsion Laboratory, JPL. JPL is based in Pasadena, California, and was founded in the 1930s by the Air Force for the purpose of investigating the possibility of adding jets to airplanes to assist in takeoff from short runways. JPL’s mission expanded to include the development of interplanetary robots. When NASA was formed in 1958, oversight of JPL was handed off from the Army to NASA. The Explorer satellite built by JPL did succeed in reaching space.
After Explorer, two programs were started in 1959 and run by JPL in parallel: the Pioneer program and the Ranger program. The Pioneer satellite was intended to be sent to the moon for reconnaissance for a future manned moon landing. The early satellite programs—the Explorer, Pioneer, and Ranger—were not without significant problems, and so much so, that early satellites were launched in pairs to increase the odds of success. The Pioneer satellite used rockets and satellites designed by the Air Force. Pioneer’s first seven attempts to reach the moon failed. Later on, the Pioneer name was reused for a different mission, the study of space weather.
The Ranger satellite was originally planned to crash land into the moon, but it took until the fourth Ranger in the series to get there, and though Ranger 4 hit the moon, it landed on the dark side, out of radio contact. Ranger 5 missed the moon by 450 miles. Ranger 6 hit the moon, but its data transmission system failed. Ranger 7, 8, and 9 were successes, and Ranger 7 sent 4300 images back to Earth in its short 17-minute lifespan.
The Ranger program ended at Ranger 9 and was replaced by the Surveyor program. The Surveyor was a series of lunar orbiter missions with the purpose of photographing the surface of the moon, again in advance of a manned moon mission. Of the seven Surveyors launched, the first was successful from the start. Its landing was broadcast live on TV all over the world. Five Surveyors landed, one crash landed, and one orbiter and one lander failed in flight.
The first Russian moon mission series was Luna. The first Luna that survived launch, Luna 1 (the Russians did not number their failures), missed its target and ended up orbiting the sun. Luna 3 was the first spacecraft to take photos from space and transmit images back to Earth. Luna 3’s pictures were taken from a distance of 3800 miles and were the first photos of the dark side of the moon. How the Luna did this was by use of an onboard camera and film lab. Pictures was taken on photographic film, developed, and then sensed by an optical scanner in a technique similar to a fax. Images were then transmitted by FM transmitter, scanning the image line by line. The photographic technique used by the Russian spacecraft had been reverse engineered from recovered U.S. spy balloons that were shot down over Russia.
Russian satellites that were also moon rovers were called Lunokhods. The Lunokhod rover was powered by batteries and solar panels, contained an array of antennas and TV cameras, and was capable of running experiments. The first Lunokhod was launched 1969 but failed during launch. The second attempt a year later succeeded and landed in 1973.
The next target for exploration after the moon for the U.S. and Russia was Mars, and Mars turned out to be a more difficult target. The greater the distance from the Earth, the more complicated it becomes to communicate, command, orient and navigate. “. . . for the first few decades of Martian exploration, almost half the attempts failed— everything must be perfect [to succeed].”
Pyle adds cultural context on the idea of Mars, that is, Mars of the imagination populated by little green men, that is, before science discovered what Mars was really like. The idea that Mars that was populated or that Mars could sustain life, was tempered by data returned by robot satellites. When the Mariner satellites sent back images from their flybys in the mid 1960s they showed Mars to be desolate and inhospitable.
For another book that addresses the Mars of imagination, readers may be interested in 4th Rock from the Sun by Nicky Jenner, previously reviewed at NYJB.
The first lander on Mars was a result of the Viking project. One of the more difficult aspects in preparation for Viking was figuring out just where on Mars to land. Mars’ surface is rough; Pyle writes, “The closer you got to Mars, the more craters you saw. There were once again craters within craters within craters.” Adding to the difficulty in choosing a landing site was a disagreement between biologists and geologists between landing where life would be more likely to be found versus landing where the geology was more interesting.
Viking was launched in in 1975 and landed in 1976. Viking was comprised of both an orbiter and lander. The lander had color cameras, robot arms, and automated laboratories for life science experiments. Pyle describes the experiments to find signs of life and provide a study of the men who designed the experiments. The data sent back from Viking were ambiguous and inconclusive. The Mars Phoenix Explorer, which landed in 2008, performed experiments intended to resolve the ambiguity, but, Pyle writes, “the debate has not gone away.”
Russia also sent satellites to Mars. The Russian Mars 2 in 1971 was the first successful Mars orbiter, though its lander malfunctioned and crashed. The Russian Mars 3, also launched also in 1971, landed successfully but its electronics failed after 90 seconds. These satellites were followed by Mars 4, 5, 6, and 7, all having problems of their own and all fascinating in their ambitiousness.
NASA went back to Mars in 2004 with the Mars Explorer, which was comprised of twin rovers named Spirit and Opportunity. Pyle interviewed members of the Mars Explorer team at JPL, and presents details of the Explorer lander’s complex landing mechanism, which consisted of a heat shield called an aeroshell, thrusters, ejecting weights, a supersonic parachute, and an airbag. All were combined in a landing rocket pack. The final descent was made by lowering the rover by tether.
The most recent mission to Mars by NASA was just last year. The InSight lander was accompanied by two smaller satellites called CubeSats. The CubeSats, as a combined pair, are called Mars Cube One, or individually called MarCO-A and MarCO-B. Mars Cube One provided status updates on the lander during the landing, and as well, showcased future capabilities of CubeSats.
The next future mission to Mars, Mars2020 has been planned to launch in, you guessed it, 2020. This mission will have, as before, a rover with instruments for conducting experiments, but in addition will have a robotic helicopter and will gather rock samples for future retrieval. One of the experiments on the rover, the Mars Oxygen In-Situ Resource Utilization Experiment, MOXIE, will as an engineering test, generate oxygen from Mars’ mostly carbon dioxide atmosphere. One of this reviewer’s day job’s tasks is to support the flight software that runs on MOXIE. It is expected that in the future a scaled-up MOXIE will generate enough oxygen to fuel a manned return trip from Mars.
After Mars, Pyle recounts satellite missions to Venus which, despite Venus’ closeness to Earth, has been rarely visited. When Venus was first visited by satellite, it was found to be “a true hell hole of a planet” with a surface temperature above 800 degrees Fahrenheit, and an atmosphere that is 96% carbon dioxide. Pyle tells us Venus is “The poster child for runaway global warming.”
The first of the Soviet Union’s Venera series of satellites sent to Venus was launched in 1961, but it took 11 launches over a period of six years to finally get there. The Venera 4 launched in 1964 conducted a flyby but also carried a lander. Venera 4 provided the first direct measurement of another planet’s atmosphere, however the lander did not survive the trip through Venus’ atmosphere.
Venera 7 launched in 1970 survived landing on the surface of Venus, lasting 23 minutes before succumbing to heat. Venera 8, which landed in 1972, lasted one whole hour. Venera 9 launched in 1975, comprised of both an orbiter and lander, and made several space firsts. Venera 9 was the first satellite to orbit another planet, and the first satellite to send an image to Earth from another planet. Venera 9’s lander, however, lasted only 53 minutes. The Russian Veneras were followed by Vegas, which were more capable; the Vegas floated above Venus’ surface by balloon.
The U.S. flew past Venus in 1962 with Mariner 2, and the Mariner 5 provided a flyby in 1967. The early Mariner series were not designed with cameras, it was believed that there would be nothing to see as Venus is wrapped in clouds. NASA flew two Pioneers to Venus in 1978, the first was an orbiter that survived 14 years. The second flew into Venus’ atmosphere and lasted until it overheated. That Mariner released four smaller probes that were not expected to survive landing though one did and continued transmitting for almost an hour. NASA’S Magellan satellite launched in 1989 remained in orbit around Venus for almost four years making a high-resolution radar map of the planet’s surface.
NASA has a space rover in development that is planned for a future Venus mission. The rover is called AREE for Automaton Rover for Extreme Environments. In order to operate in Venus’ heat, AREE will be fully mechanical using gears and cogs for automation and computation and will communicate by using of a reflector with mechanical shutters in a manner similar to Morse code. AREE is also being considered for future missions to Jupiter and Saturn.
Heat is not the only concern in designing a robotic satellite, so is surviving harmful radiation, and generating enough power to function. When Pioneer 10 and 11 flew by Jupiter, the radiation emanating from Jupiter was so strong it generated false commands to the satellite. Both the Pioneer series (of which there were 11 satellites) and the Voyager series (of which there were only but two) were powered by electricity generated from nuclear thermopiles.
Of the Pioneer series, Pioneer 10 was last heard from in 2003, and while Pioneer 11’s instruments failed in 1995, its communication system still worked, and was last talked to in 2002. The Voyagers were both launched in 1977, a month apart. The Voyagers visited the distant planets in our solar system with a flyby of Jupiter and its moons, then flew by Saturn and its rings and moons, Uranus and moons, and then flew by Neptune and its moons. Finally, both Voyagers exited the solar system. The Voyagers are still traveling away from the Sun, and their nuclear power supplies are expected to last until the mid 2020s. Says Pyle, “Not bad for a couple of repurposed Mariner spacecraft first designed in the 1960s.”
Satellite missions were also dedicated to travelling to Jupiter and Saturn, not just flying past. There is a chapter on the Galileo satellite mission to Jupiter and a chapter on the Cassini-Huygens satellite mission to Saturn. There is a future mission proposed to travel to Saturn’s largest moon Titan. This mission may include a robot submarine to explore Titan’s methane ocean. The submarine would be powered by radioisotropic generators (a fancy word for nuclear power generated electricity), and use a ballast of neon gas instead of air; Earth air would liquify at Titan’s icy temperatures.
Interplanetary Robots also mentions a number of planned and speculative space projects. Planned missions include the James Webb Telescope—the replacement for the Hubble and TESS, the Transiting Exoplanet Survey Satellite—intended to discover distant Earthlike planets. Of the more speculative missions, one is aptly named Breakthrough Starshot, an initiative started in 2016. Breakthrough Starshot is a plan to build a fleet of light sail spacecraft to travel to the nearest star to the Sun, Proxima Centauri. Pyle identifies the precursor to Breakthrough Starshot, Project Longshot, a proposal dating back to 1980. Though Project Longshot never got further than paper, this satellite would have been an unmanned probe powered by nuclear pulses from a fission reactor that powered lasers to heat helium 3/deuterium pellets into a fusion reaction. It was believed that by using nuclear propulsion Longshot would reach 5% of the speed of light. Woohoo!
Interplanetary Robots includes photographs and end notes.