A Russian Moon?
by Dwayne Day
|The Russians could possibly by the most active nation conducting lunar exploration in the next decade.|
Although they have experience with landing robotic craft on the Moon, launching a Moon orbiter before a lander is a better approach for the Russians because they need to re-learn how to walk before they can start to run. In late 2011 they suffered an embarrassing failure of their overly-ambitious Fobos-Grunt mission. The spacecraft fell silent almost immediately after launch, circled the Earth for a few weeks, and finally reentered. Many independent observers had predicted that Fobos-Grunt would fail because it was too complicated for a space program that had not built a planetary spacecraft in over a decade and a half (see “Red moon around a red planet,” The Space Review, November 7, 2011). The only real surprise was that the spacecraft failed so early, probably a sign that Russian quality control and systems engineering are both in bad shape, something that has been reinforced by a series of launch vehicle problems. Russian planetary science plans in recent years appeared to experience the “Christmas Tree” problem that American robotic spacecraft suffered from in the 1980s. This is where a mission gets more and more complex as scientists add more instruments, increasing the cost and the risk that something will go wrong. Fobos-Grunt had this problem in spades and some Russian lunar missions appeared to be succumbing to it as well. A single mission including an orbiter, lander, and rover, some of them from different countries, is very hard to integrate, but until recently such a mission was in Russian lunar plans.
A single lunar orbiter is a good place for the Russians to re-start their planetary science program (see “Red planet blues,” The Space Review, November 28, 2011). While they clearly want to pursue a science program, they also need to rebuild design and mission management capabilities lost decades ago. An orbiter, as long as it is not too complex, will provide experience that Russian engineers can then apply to a more challenging lander. Unfortunately for India, the changing Russian plans created too much turmoil for them, and India has now decided that instead of flying its Chandrayaan-2 rover on a Russian lunar lander, the Indians will go it alone and develop both a lander and a rover, although at the moment it is not clear how this affects their own schedule.
A lot of countries are going to be sending spacecraft to the Moon in the next few years. Right now the United States has the only operational Moon mission, the Lunar Reconnaissance Orbiter, launched in 2009, having ended its GRAIL mission a few weeks ago. But there are quite a few other Moon missions currently in the development or planning stages. NASA will launch another orbiter, LADEE, probably in November. This year China is planning on landing a spacecraft on the Moon, the first landing there in forty years. After that there are Indian, Chinese, Japanese, and possibly even private missions that will land on the Moon.
One of the unfortunate casualties of the Cold War was the loss of a vigorous and productive Soviet space science program. Although it was better known for its engineering accomplishments—getting somewhere first, only to be followed by the Americans often with a much better suite of scientific instruments—the Soviet space program accomplished a lot of important science during the Cold War. When it ended, Russia pretty much stopped launching scientific spacecraft, and then faltered when it tried again.
Luna-Glob has been under discussion for over a decade. In 1999, several Russian scientists proposed a spacecraft known as Luna-Glob that would focus on two primary scientific goals: determining the internal structure of the Moon, and analyzing the composition of possible volatiles at the lunar poles. The scientists noted that the origins of the Moon were still in dispute, as were key questions about its internal structure, such as whether or not it had a core. Although Apollo placed seismic sensors on the Moon, because they were all relatively close together, the sensors did not “see” deep beneath the lunar surface.
|At least from the outside it looks like the Russians are slowly developing a more rational approach to lunar science and exploration both from a scientific standpoint and from an experience base standpoint.|
The Russians proposed a seismic experiment that could provide greater data. This would consist of two “landers”—large penetrometers similar to those on the Russian Mars 8 spacecraft and equipped with wideband seismometers—and ten high-speed penetrators piercing the lunar soil space approximately 2–3 kilometers apart and forming an area approximately 10 kilometers in diameter. The large penetrometers were intended to survive an impact up to 1000 gravities upon striking the lunar surface and would have been placed close to the Apollo 12 and Apollo 14 landing sites. The smaller penetrometers would have struck the surface at 2.5 km/s and 10,000-g deceleration. They would have buried themselves up to 10 meters into the surface. The penetrometers were to operate for up to a year on the lunar surface. Using several seismic data processing methods, they could obtain information on the Moon’s internal structure.
The penetrators would be dropped from a spacecraft on approach trajectory. While an orbiter entered lunar orbit, another spacecraft would then decelerate to land at the lunar south pole, striking the surface at high velocity, but below 500 gravities. It would be similar to the “egg” used on Soviet Luna missions in the 1960s. It would be equipped with a TV camera with eight lenses for obtaining a panoramic view of the landing site as well as measuring the physical characteristics of the soil. By examining the albedo value and reflective properties of the soil at different wavelengths, and the reflectance characteristics of the surface under illumination at different angles, scientists would try to determine what, if any, volatiles the soil contained. The lander would also be equipped with a neutron detector, a gamma-ray spectrometer, a mass spectrometer, and several other instruments. Meanwhile, the orbiter would relay the data from the polar station back to Earth. The goal would be to land the polar station near the south pole in a shadowed region. The scientists selected a crater 56 kilometers in diameter for the landing.
This proposed spacecraft would have been highly complex, consisting of ten penetrators, two landers, a polar lander, and an orbiter. But although the 1999 proposal for Luna-Glob was not pursued, its science goals survived and were incorporated into a newly proposed mission with the same name.
By the early 2000s Russia’s Institute for Space Research decided to send two spacecraft to the Moon, originally scheduled for 2013–2014, each of them consisting of orbiters and landers. Luna-Glob would be an all-Russian mission and would follow Luna-Resource, a joint mission with India carrying the Chandrayaan-2 rover, the next step in India’s exploration of the Moon. The two spacecraft would have nearly identical scientific payloads in order to minimize costs. The plan was for both Luna-Glob and Luna-Resource to land at the lunar poles. Luna-Glob would have a drill for penetrating the surface, and both spacecraft would have manipulators for delivering samples to onboard analytic instruments.
As of a few years ago, the overall science goals of both missions were to study the content of volatiles in the polar regolith and their transport and accumulation, study the content of elements of the regolith for comparison with previously returned samples, and to measure key isotopic ratios of lunar material. In addition, the spacecraft would study the lunar exosphere in the polar region, including dust, and investigate how the solar wind interacts with the surface. Finally, the spacecraft would study subsurface thermal variations.
A manipulator arm on each lander spacecraft would have two instruments, an infrared spectrometer and a TV camera. The internal instruments would include the composition analysis system consisting of a thermal differential analyzer, gas chromatograph, and a mass spectrometer. The spacecraft would also carry a laser mass spectrometer.
|We can only hope that the Russians carry through with these plans, which are starting to look like a systematic scientific exploration of Earth’s nearest neighbor.|
Several other instruments would be mounted on the spacecraft, including an imaging spectrometer for measuring mineralogical composition, and the ADRON-L, for active neutron and gamma-ray analysis of nuclear composition. A radiometer-thermometer would measure variations in the temperature of the subsurface down to one meter. In addition, a contact thermometer would measure the lunar surface temperature, and Luna-Glob would have an instrument for measuring the temperature in the hole made by the spacecraft’s drill, which could penetrate 50–90 centimeters below the surface. The spacecraft would have instruments for measuring dust flux on the surface as well as neutral and charged particles at the landing site. In addition, the spacecraft would have a seismic instrument for acting in concert with other seismic spacecraft landed by other nations on the Moon. For example, one of NASA’s proposed missions in its New Frontiers class is a Lunar Geophysical Network consisting of several landers.
Two years ago, and just before the failure of Fobos-Grunt, the Russians laid out a mid-term “Russian Lunar Program” consisting of Luna-Resource in 2013, Luna-Glob in 2013–2014, a Luna-Rover mission in 2015 or later, to be followed by a Luna-Sample Return mission. Part of the goal of the sample return mission would be to develop techniques for returning future cryogenic samples from the Moon—in other words, keeping the volatiles frozen at or near their temperature when collected.
It appears that the original plan to fly Luna-Resource first was prompted by the presence of the Indian rover, which was going to be a paying customer. Both the Luna-Glob and Luna-Resource missions included orbiters and landers together. In the early months of 2012, following the Fobos-Grunt failure, some Russian scientists talked about immediately re-flying that complex mission. But those plans apparently never solidified. By 2012, the Luna-Glob and Luna-Resource missions had been flipped in order, and the orbiter and lander parts of Luna-Glob separated. Now the orbiter and lander parts of Luna-Glob have been flipped on the schedule. Of course, all of the dates have slipped by a number of years. The schedule and mission changes reflect many issues, including the Russian experience base and budgets, although over a year ago Russian space expert Anatoly Zak pointed out that Russian space science programs are not short of funds, but do lack skilled personnel.
At least from the outside it looks like the Russians are slowly developing a more rational approach to lunar science and exploration both from a scientific standpoint and from an experience base standpoint. Separating the orbiter missions made good sense because it is difficult to build two spacecraft simultaneously, not to mention integrating two separate spacecraft into a single launch. Flying the orbiter first makes sense as well, because it is a simpler spacecraft than the lander, and its data can also be used to select landing sites. The Luna-Glob orbiter is planned to operate for up to three years and carry instruments for mapping mineral and ice distribution on the lunar surface as well as electric and magnetic fields and dust and plasma, which constitute a sort of lunar atmosphere.
We can only hope that the Russians carry through with these plans, which are starting to look like a systematic scientific exploration of Earth’s nearest neighbor. If they carry out only some of their current plans, they may still perform more significant lunar science and exploration than China.