China Goes Back to the Moon

Launch of the Chang’e 2 Aboard a Long March 3C Image Credit: Xinhua/Li Gang

Three years ago, China became the third nation to orbit a spacecraft around the Moon, with the Chang’e-1, in October 2007. India subsequently successfully orbited the Moon with Chandrayaan-1 in October, 2008. Now, China is on its way back. The Chang’e 2 spacecraft was launched on Friday, the national day of China, at 10:59:57 UTC (3:59 AM Phoenix), beginning the second phase of China’s lunar exploration. The launch was from the Xichang Satellite Launch Center in southwest China’s Sichuan Province. Chang’e 2 was launched directly into an Earth-Moon transfer orbit.

The perigee is 200 km and the apogee is about 380,000 km. Once in orbit, the perigee will be reduced to 15 km and the apogee to 100 km. The cameras on the Chang’e 2 should have a resolution of 10 meters at 100 km and 1.5 meters at the 15 km low point, a great improvement compared to the 120 meters of their first lunar orbiter. The new spacecraft will study the lunar surface using gamma-ray and x-ray spectroscopy, in order to detect the content and distribution of silicon, magnesium, aluminum, calcium, titanium, potassium, thorium and uranium. The thickness of the lunar soil and other properties will be probed by microwave radiation of the lunar surface at 3.0GHz, 7.8GHz, 19.35GHz and 37GHz.

Grand LaGrange

The Artemis (Acceleration, Reconnection, Turbulence and Electrodynamics of the Moon’s Interaction with the Sun) mission is designed to study the Sun’s magnetosphere on opposite sides of the moon. The mission utilizes two of the five THEMIS spacecraft, which have completed their original mission. The five spacecraft were launched in 2007, and completed their research earlier in 2010. Their mission was to investigate the auroras in the Earth’s atmosphere and why they dramatically change from slowly shimmering waves of light to wildly shifting streaks of color. The data from the spacecraft will provide scientists with important details on how the planet’s magnetosphere works and the important Sun-Earth connection. Now, two of these craft are headed toward the Moon and the two Lagrange points, EML-1 and EML-2. As shown in the two diagrams below, EML-1 (L-1) lies between the Earth and the Moon (about 61,000 km above the Moon’s surface) and EML-2 (L-2) lies beyond the Moon at the same distance.

Artemis Spacecraft P1 Earth Moon Lagrange Orbits Image Credit: NASA / Goddard

Artemis Spacecraft P1 Earth Moon Lagrange Orbits – Side View Image Credit: NASA / Goddard

The first spacecraft (P-1) has migrated from Earth orbit to L-2 and entered a Lissajous orbit about L-2. These orbits (as seen in the diagrams above) are dynamically unstable, and require adjustments from on-board thrusters. The spacecraft will take from 14 to 15 days to complete a single loop. The plan is for the two spacecraft to spend about three months monitoring the influence of the magnetospheres of the Earth and the Moon on the solar wind. This will provide the first three-dimensional perspective of how energetic particle acceleration occurs near the Moon’s orbit as well as the space environment behind the Moon. After this period, the spacecraft at L-2 will migrate to L-1 and join its sister. In late March of 2011, both spacecraft will maneuver into elliptical orbits around the Moon and continue to observe magnetospheric dynamics, solar wind and the space environment over the course of several years. The research to be conducted by the Artemis program is important for several reasons. One is the pure research itself. Second is the fact that both L-1 and L-2 are proposed as propellant and supply depots for the robotic and manned exploration of the Moon and the Solar System. Understanding the solar radiation environment at these locations will be important for manned operations and the health of the astronauts (see the related problems associated with Galactic Cosmic Rays (GCR) – The 800 Pound Gorilla). For the importance of propellant depots, see the discussion in this post Post Augustine Commission – ULA Says “Fly Me to The Moon”, and the uses of propellant depots here The Augustine Commission – Final Report – Hits and Misses – Wrapped Up

1959 – Twelve Men On The Moon

Copernicus, Eratosthenes and Project Horizon Image Credit: NASA / GSFC / Arizona State University The Lunar Reconnaissance Orbiter Camera team recently released this image featuring the famous crater Copernicus with its ejecta splashed across much of the face of the Moon. Copernicus and the crater Eratosthenes lie just south of Mare Imbrium. To the east of Copernicus and south of Eratosthenes lies the nearly featureless plain called Sinus Aestuum. Here, just southeast of Eratosthenes lies the location of a proposed Moon Base. In addition to the scientific value of this area, the rich ores of the Rima Bode regional dark mantling deposit lie nearby.

On 20 March 1959, Arthur G. Trudeau, Chief of Research and Development for the U.S. Army, submitted a request for the study to place a lunar outpost on the Moon. The result was Project Horizon, a plan (dated 9 June 1959) to place a military base with 10-20 men on the surface of the Moon by 1965. Full details are in Vol. I and Vol. II (pdf). The introduction to the proposal stated that the establishment of a lunar base would: Demonstrate the United States scientific leadership in outer space Support scientific explorations and investigations Extend and improve space reconnaissance and surveillance capabilities and control of space Extend and improve communications and serve as a communications relay station Provide a basic and supporting research laboratory for space research and development activity Develop a stable, low-gravity outpost for use as a launch site for deep space exploration Provide an opportunity for scientific exploration and development of a space mapping and survey system Provide an emergency staging area, rescue capability or navigational aid for other space activity It further stated the following, prescient about the Soviet manned capability, but extremely optimistic about the timetable for the Moon Base: Advances in propulsion, electronics, space medicine and other astronautical sciences are taking place at an explosive rate. As recently as 1949, the first penetration of space war accomplished by the US when a two-stage V-2 rocket reached the then unbelievable altitude of 250 miles. In 1957, the Soviet Union placed the first man-made satellite in orbit. Since early l958, when the first US earth satellite was launched, both the US and USSR have launched additional satellites, moon probes, and successfully recovered animals sent into space in missiles. In 1960, and thereafter, there will be other deep space probes by the US and the USSR, with the US planning to place the first man into space with a REDSTONE missile, followed in 1961 with the first man in orbit. However, the Soviets could very well place a man in space before we do. In addition, instrumented lunar landings probably will be accomplished by 1964 by both the United States and the USSR. As will be indicated in the technical discussions of this report, the first US manned lunar landing could be accomplished by 1965. Thus, it appears that the establishment of an outpost on the moon is a capability which can be accomplished. Underlying all of this was the traditional von Braun team approach: paramount to successful major systems design is a conservative approach which requires that no item be more “advanced” than required to do the job. It recognizes that an unsophisticated success is of vastly greater importance than a series of advanced and highly sophisticated failures that “almost worked. “ The proposal discusses the ongoing development of the Saturn I by ARPA, expecting it would be fully operational by 1963. The Saturn I stood more than 200 feet tall, and would be superseded by the Saturn II in 1964, standing 304 feet tall. By the end of 1964, a total of 72 Saturn I rockets would have been launched on various programs of discovery, including 40 to support the manned lunar base. In order to support the full complement of 12 men, 61 Saturn I and 88 Saturn II launches would be required by the end of 1966, landing 490,000 pounds of cargo on the lunar surface. 64 launches were scheduled for 1967, landing an additional 266,000 pounds of supplies. The total cost of the eight and one-half year program was estimated to be $6 Billion. The von Braun team thought very large indeed.

Project Horizon – Lunar Base 1965 Image Credit: US Army Project Horizon – Rockets Image Credit: US Army Orbital Trajectories Image Credit: US Army

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