China's 5-year space plan

The wide-ranging white paper lays out the purpose of China's space program as well as its vision and principles of development. It also includes a summary of China's major developments in space since 2011, and the major tasks ahead for the next five years.

The document also includes policies and measures for development and the role of international exchanges and cooperation.

In terms of deep-space exploration, the white paper explains that China will continue its lunar exploration project, and strive to attain the automated extraterrestrial sampling and returning technology by space explorers.

Three strategic steps

"We plan to fulfill the three strategic steps of 'orbiting, landing and returning' for the lunar exploration project by launching the Chang'e-5 lunar probe by the end of 2017 and realizing regional soft landing, sampling and return. We will launch the Chang'e-4 lunar probe around 2018 to achieve humanity's first soft-landing on the far side of the moon, and conduct an in-situ and rover detection and relay communications misison from the Earth-moon L2 point."

Also noted is that through China's lunar exploration project, topographic and geological surveys will be implemented and laboratory research conducted on lunar samples; geological survey and research as well as low-frequency radio astronomy observation and research will be carried out targeting the landing area on the far side of the moon for a better understanding of the formation and evolution of the moon.

Next lunar probe

At the press conference hosted by the State Council Information Office, Wu also detailed work underway on Chang'e-5, targeted for liftoff at the end of 2017.

"We will take samples from the surface of the moon as well as different depths of the moon rocks after drilling, and the samples will be used by scientists for scientific research," Wu said.

Wu added that work related to Chang'e-5 is going smoothly.

Mars and beyond

Explained in the white paper is that China intends to execute its first Mars exploration operation, and grasp key technologies for orbiting, landing and roving exploration.

China plans to launch this Mars probe by 2020 to carry out orbiting and roving exploration.

"It will conduct further studies and key technological research on the bringing back of samples from Mars, asteroid exploration, exploration of the Jupiter system and planet fly-by exploration. When conditions allow, related projects will be implemented to conduct research into major scientific questions such as the origin and evolution of the solar system, and search for extraterrestrial life," the paper explains.

Raising human spaceflight capacity

In the category of human spaceflight, the white paper notes that China plans to launch the Tianzhou-1 cargo spacecraft to dock with the now Earth-orbiting Tiangong-2 space laboratory, "and research and master key technologies for cargo transport and replenishment to accumulate experience in building and operating a space station."

"We strive to acquire key technologies and conduct experiments on such technologies," the paper continues, "to raise our manned spaceflight capacity, laying a foundation for exploring and developing cislunar space." [China's Tiangong-2 Space Lab in Pictures]

In June 2016, China's new Wenchang launch center on Hainan Island celebrated its first launch. Renovations have also been accomplished in the Jiuquan, Taiyuan and Xichang launch sites, "forming a launch site network covering both coastal and inland areas, high and low altitudes, and various trajectories to satisfy the launch needs of manned spaceships, space laboratory core modules, deep space probes and all kinds of satellites," the document explains. "The integrated capacities and functions of space launch sites will be enhanced and exploited to meet various needs."

Historical starting line

The white paper concludes by noting that the country is "standing at a new historical starting line," with China "determined to quicken the pace of developing its space industry, and actively carry out international space exchanges and cooperation."

Since 2011 China has signed 43 space cooperation agreements or memoranda of understanding with 29 countries, space agencies and international organizations.

To access the full white paper — "China's Space Activities in 2016" — visit: http://www.globaltimes.cn/content/1025885.shtml.

Leonard David is author of "Mars: Our Future on the Red Planet," published in October by National Geographic this October. The book is a companion to the National Geographic Channel six-part series, Mars. A longtime writer for Space.com, David has been reporting on the space industry for more than five decades. Follow us @Spacedotcom, Facebook or Google+. Originally published on Space.com.

RELATED: Welcome to Proxima b, Our Nearest 'Earth-like' Neighbor

Though we know that Proxima b is there, we can only guess at its composition and have no clue whether or not it possesses any water. But new evidence suggesting Proxima Centauri is indeed a distant sibling of the Alpha Centauri could help us find out.

Proxima Centauri was only discovered a century ago and, since then, astronomers have been trying to understand its motion in the sky, a task that becomes very complicated when considering how dim it is. Red dwarfs are many times smaller and produce only a fraction of the light of our sun. But using the High Accuracy Radial velocity Planet Searcher (HARPS) instrument at the ESO's La Silla Observatory in Chile, astronomers have, for the first time, gained precision measurements of the dim star's radial velocity, a key metric if we are to understand if it is in any way related to Alpha Centauri.

The HARPS instrument is extremely sensitive to the wobble of stars as small exoplanets orbit around them, gravitationally tugging at them. Indeed, it was the HARPS instrument that discovered the tiny wobble of Proxima Centauri, revealing the presence of Proxima b. But this time, HARPS was able to deduce the velocity at which the tiny star is moving away from us and compared it with the radial velocity of Alpha Centauri. Both radial velocities closely match, which means that, in all likelihood, Proxima Centauri has a wide orbit around Alpha Centauri. They are therefore, probably, gravitationally bound.

RELATED: Proxima Centauri Is Like Our Sun... on Steroids

Though this is a significant find — indeed, the question of whether or not all three stars are in orbit around one another has been vexing astronomers since Proxima Centauri was first spotted — it could reveal an interesting tidbit about the nature of Proxima b itself.

If Proxima Centauri and Alpha Centauri are gravitationally bound, this gives us a clue that the group formed from the same star-forming nebula billions of years ago. They are all therefore the same age. Over time, the trio's orbits evolved and Proxima Centauri for some reason was thrown away from the Alpha Centauri binary. In research to be published in the journal Astronomy & Astrophysics, the researchers speculate that before Proxima Centauri was ejected and sent on the lonely orbit it's in today, a planet formed far from the star and then migrated to a lower orbit. As it occupied such a distant (and cold) orbit, it would have likely been an icy world and that ice could have been water. And now Proxima b is orbiting in a very habitable location for liquid water to exist on its surface, then perhaps — just perhaps — it possesses water to this day.

Though it's a bit of a reach to be making any assumptions about the water content of a planet we cannot directly see, it's interesting to think that Proxima b may have formed with an abundance of water ice and it's hard not to get excited for the artistic renderings of alien oceans under a red sun.

RELATED: Proxima B: Another Earth Just Next Door

Originally published on Seeker.

ISS consists of a wide-angle and a narrow-angle digital camera, which are sensitive to visible wavelengths of light and to some infrared and ultraviolet wavelengths. The monochrome image at the top was captured by ISS from a distance of about 398,000 miles (640,000 kilometers) and is almost cloud-free. However, the bottom image was captured from about 28,000 miles (45,000 km) by the VIMS at the longer, infrared wavelength, and bright clouds are visible in Titan's northern skies. 

"Even though these views were taken at different wavelengths, researchers would expect at least a hint of the clouds to show up in the upper image," NASA officials said in a statement. "Thus, they have been trying to understand what's behind the difference."

Based on atmospheric models, scientists have predicted that clouds will become more common at high northern latitudes during summer on Titan. Since 2004, Cassini has documented alterations in weather patterns as seasons change on Titan. Images collected by Cassini will help track the onset of clouds in the north, where Titan's lakes and seas are located, NASA officials said. 

"The answer to what could be causing the discrepancy [between the ISS and VIMS images] appears to lie with Titan's hazy atmosphere, which is much easier to see through at the longer infrared wavelengths that VIMS is sensitive to (up to 5 microns) than at the shorter, near-infrared wavelength used by ISS to image Titan's surface and lower atmosphere (0.94 microns)," NASA officials said in the statement. 

Differences in illumination geometry or changes in the clouds themselves were ruled out, as the images taken by ISS and CIMS were made over the same 24-hour period. 

"High, thin cirrus clouds that are optically thicker than the atmospheric haze at longer wavelengths, but optically thinner than the haze at the shorter wavelength of the ISS observations, could be detected by VIMS and simultaneously lost in the haze to ISS — similar to trying to see a thin cloud layer on a hazy day on Earth," NASA officials said. "This phenomenon has not been seen again since July 2016, but Cassini has several more opportunities to observe Titan over the last months of the mission in 2017, and scientists will be watching to see if and how the weather changes."

Follow Samantha Mathewson @Sam_Ashley13. Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.