China’s long march to the moon
This article originally appeared in the June 19, 2017 issue of SpaceNews magazine.
China is readying a robotic land, grab and go sampling of the moon, a multi-faceted mission that is a harbinger of things to come and a key step to landing a human crew on that neighboring world.
Chinese engineers are wrapping up work on the Chang’e-5 lunar mission for a targeted November launch atop a Long March 5 booster. It will depart from the newly completed Wenchang Space Launch Center in south China’s Hainan Province. If successful, this robotic mooncraft would carry the first lunar samples returned to Earth in over 40 years.
The country’s Chang’e-1 and -2 circled and charted the lunar surface in 2007 and 2010, respectively, with the Chang’e-3 spacecraft soft landing on the moon in December 2013, unleashing the wheeled Jade Rabbit rover to reconnoiter the lunar surface. In October 2014, the Chang’e 5-T1 probe carried out an eight-day circumlunar voyage that included the evaluation of critical reentry technology and a demonstration of techniques for hauling bits and pieces of the moon back to Earth.
According to China’s state-run news services, Chang’e-5 consists of four parts: the orbiter, ascender, lander, and Earth-reentry module. The lander and ascender form a combination that will touchdown on the moon to conduct the robotic sample collection mission. The primary task of collecting samples on the moon makes use of a drill to gather specimens beneath the lunar surface. Also to be used is a mechanical arm to pick up pieces from the moon’s landscape.
Then there’s the return leg of the Chang’e-5 mission, from the moon back to Earth. That step involves docking in lunar orbit and transferring the moon material from the ascender into the reentry capsule. The lunar samples will be shot back to the Earth contained within the mission’s reentry module.
Scoop and coring
“For them, it’s the next step in their plan of demonstrating technology and increasing capabilities,” said Jeff Plescia, a planetary scientist at The Johns Hopkins University’s Applied Physics Laboratory in Laurel, Maryland.
Plescia said that the mission design for Chang’e-5 is different from the approach taken by the Soviet Union’s Luna sample-return program. The Soviets deposited the sample directly into the Earth-return capsule then lobbed the specimens from the moon; a transfer in lunar orbit was not required. Also, the Soviet Union selected moon landing spots that permitted a direct-return trajectory to the Earth, he said.
Chang’e-5’s sampling system allows both scoop samples and coring. “Cores are always good for stratigraphy and trying to understanding the geologic history of a site, but the largest fragment is always limited by the core diameter. A scoop sample has the potential to collect a wide range of fragment sizes,” Plescia said.
Chang’e-5’s landing site was announced during the Global Space Exploration Conference (GLEX) 2017 meeting June 6-8 in Beijing. Liu Jizhong, director of China Lunar Exploration and Space Engineering Center of the China National Space Administration, identified the Mons Rümker region within a part of the moon’s Oceanus Procellarum.
Mons Rümker is a relatively young volcanic site, Plescia said. “It’s a most excellent choice. There are lots of domes and small features that suggest a style of volcanism very different from the emplacement of mare lavas on the moon,” he said.
Chang’e-5 could help in sorting out how the eruptive processes evolved, how the chemistry has changed, how old the rocks are in this area, and what that indicates for the thermal history of the moon, Plescia said.
China developed a moon exploration strategy some time ago and has been implementing each step as planned, Plescia said. “I have no doubt that they will land humans on the moon and certainly before the U.S. ever returns to the moon.”
“I believe that the mission, if successful, will prove a new landmark achievement for China, with important implications for the international space community too,” said Marco Aliberti, a resident fellow of the European Space Policy Institute in Vienna and author of the 2015 book “When China Goes to the Moon…”
“Technically, it is the most sophisticated and difficult exploration mission China will embark upon during the country’s 13th five-year plan, because of the many technological breakthroughs that China has not yet fully mastered,” Aliberti told SpaceNews.
Those steps forward include encapsulation of lunar samples, liftoff from the lunar surface, lunar-orbit-rendezvous- and docking-operations and re-entry at high speed back to Earth. “All these techniques would be important firsts for China,” he said, “and are all condensed in one mission.”
Aliberti said that, programmatically, Chang’e-5 will not only mark the realization of the third and final phase of the Chang’e program (orbiting the moon, soft landers/rovers, and sample return) but more importantly sets the stage for China’s potential fourth phase of exploration that bridges the Chinese Lunar Exploration Program and the human spaceflight program – a melding that results in human footprints on the moon.
Politically, the mission could prove a very potent tool internally for Chinese President Xi Jinping and the Chinese dream of national rejuvenation, Aliberti said. “I think the mission might also refuel the idea of an intra-Asian space race.”
Cislunar space agenda
China’s moon goals are primarily strategic, not scientific, said Paul Spudis, a senior staff scientist at the Lunar and Planetary Institute in Houston. “I believe that all of China’s lunar missions serve the purpose of developing their capability to access and use the various levels of cislunar space,” he said.
The sample return of Chang’e-5 is another milestone in their tabulation of capability, Spudis said. “They have already demonstrated the ability to soft-land,” he said. “The return from the surface to orbit and then back to Earth are the next logical steps.”
Spudis pointed out that China’s plan to rendezvous in lunar orbit with an orbiting spacecraft before Earth return mimics the tactic taken by the U.S. Apollo moon landing program. Every step of a human mission will have been completed by some aspect of one of the Chinese Chang’e robotic mission series, he said, “and I have no doubt that they are preparing for human lunar missions and they could come very quickly, say within the next five years or so.”
Robust series of missions
China’s moon exploration agenda also entails a first-ever robotic landing on the moon’s farside, slated to occur in 2018 – a mission that requires a relay satellite beyond the moon to link communications between Earth and the farside probe. Also on the books are Chinese landers that dot the moon’s north and south poles.
James Head, a planetary scientist within Brown University’s Department of Earth, Environmental and Planetary Sciences in Providence, Rhode Island, is no stranger to the moon. He worked on the NASA Apollo program, analyzing potential landing sites, studying returned lunar samples and data, and training the Apollo astronauts.
Head subscribes to the view that the Chinese Lunar Exploration Program (CLEP) is undertaking a robust series of missions designed to explore the moon and prepare for human exploration missions in the coming decades.
Heart of the symbol
“In the last 43 years, there have been no samples returned from the moon by either humans or robots,” Head said. Robotic orbiters, however, have provided significant new remote-sensing data that have permitted detailed maps to be made of the mineralogy of the lunar surface, he said.
“Using data from U.S., Japanese, Indian, European and Chinese spacecraft and instruments, we can locate and map specific geologic units of interest, and indeed locate and map many specific outcrops of distinctive mineralogical character,” Head said. “It is clear that Chinese scientists are taking good advantage of all of these data to choose a landing site for not only the upcoming sample-return mission, but also their farside lander,” he said.
Last summer, Head visited five different planetary science laboratories at Chinese universities and institutes. “It was clear how engaged these groups were in the mapping of candidate landing sites and in preparation of sophisticated laboratory facilities in anticipation of the return of lunar samples by Chinese spacecraft…and were very interested in my experience in the training of the Apollo astronauts.”
Head said that he has no doubt that the CLEP plan will culminate in the scientific exploration of the moon by Chinese astronauts. One has only to look at the symbol of the CLEP website, he said, to see that the stylized Chinese character for the word “moon” is the heart of the symbol…and that the two horizontal lines are human footprints.
China’s Chang’e-5 undertaking is likely to stimulate two very different reactions, said John Logsdon, professor emeritus of political science and international affairs at The George Washington University’s Elliott School of International Affairs in Washington.
“One would be the competitive reaction,” Logsdon said, feeding into concern voiced by some that China is taking over the moon and we shouldn’t allow that to happen. “It could also remind us that it doesn’t make a whole lot of sense not to be cooperating with China,” he said, so their moon mission could spark both a competitive and cooperative reaction.
Logsdon said working with China would provide the United States far more insight into what they are planning, be it in the realm of robotic space exploration or their endeavors to put in place a space station in the 2020s.
NASA is barred from cooperating with its Chinese counterparts by legislation first backed by now-retired U.S. Rep. Frank Wolf (R-Va.), and presently supported by Rep. John Culberson (R-Texas), the chairman of the House appropriations subcommittee that funds NASA.
Meanwhile, the European Space Agency and the China National Space Administration are conferring about working together on a moonbase. “It’s a fair question to ask,” Logsdon said. “Are we going to be happy standing by and watching our long time space partner strike up a partnership with China in which we’re not involved?”