Astronomy

Where is the sun relative to my lunar rover?

Where is the sun relative to my lunar rover?


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I'm a robotics researcher writing orienteering code for a solar-powered lunar rover. I have two similar problems:

  1. Given the position of a robot on the moon in lunar latitude/longitude, where is the sun? That is, which direction should I orient my solar panel to maximize incidence?

  2. For testing purposes, I need to solve the same problem on Earth. Given Earth lat/lon, where is the sun?

To be honest, I'm not even sure what coordinate system to use to express the answer to these questions. I was considering a coordinate frame centered on the rover with East, North, and Up axes, but I'm open to a better suggestion!

So far, I've found some information about VSOP87 and ELP2000, and I've started reading "Astronomical Algorithms", but I'd appreciate help from the experts.

Edit

Here's what I've got so far. I can get the coordinates of the Earth-Moon barycenter using VSOP2013. If I can get from the barycenter to the center of the Earth, I can probably use EPS2000/82 to find the position of the Moon in heliocentric coordinates.

Sun->VSOP->Earth-Moon Barycenter->Earth->EPS2000->Moon

At very least, I think this would get me the moon coordinates in the sun frame. I'm hoping it would also give me the orientation of the Moon in the sun frame?


If you like Python then see Skyfield; Observing from a Moon location which I believe will do exactly what you need! Also see for example this answer to Ephemeris for lunar body-centered body-fixed coordinates? written by Skyfield's author.

For example, you posted your question at2020-04-20 15:21:36 UTC. Let's say your rover has just driven up to Surveyor III at3° 0' 58.03" S, 23° 25' 4.48" W (-3.01612°, -23.41791°)(read more about Surveyor III in How did Apollo-12 manage to land next to Surveyor-3? First “Space-Tourists”?)

At that moment the Sun was below the horizon. The output of the script below is

RA: 01h 54m 39.28s Dec: +11deg 45' 38.6" alt: -38deg 30' 34.6" degrees (below the horizon) az: 265deg 50' 21.5" degrees around the horizon from north

I can get the coordinates of the Earth-Moon barycenter using VSOP2013

factoids: VSOP is what PyEphem uses under the hood. It is currently in maintenance mode maintained by the same person who wrote Skyfield.


#!/usr/bin/env python # -*- coding: utf-8 -*- # adapted from https://rhodesmill.org/skyfield/planetary.html from skyfield.api import PlanetaryConstants, Loader load = Loader('~/Documents/fishing/SkyData') # avoids multiple copies of large files ts = load.timescale(builtin=True) t = ts.utc(2020, 4, 20, 15, 21, 36) eph = load('de421.bsp') earth, moon, sun = [eph[thing] for thing in ('earth', 'moon', 'sun')] pc = PlanetaryConstants() pc.read_text(load('moon_080317.tf')) pc.read_text(load('pck00008.tpc')) pc.read_binary(load('moon_pa_de421_1900-2050.bpc')) frame = pc.build_frame_named('MOON_ME_DE421') Surveyor_III = moon + pc.build_latlon_degrees(frame, latitude_degrees = -3.01612, longitude_degrees = -23.41791) apparent = Surveyor_III.at(t).observe(sun).apparent() ra, dec, distance = apparent.radec() print('RA: ', ra) print('Dec: ', dec) alt, az, distance = apparent.altaz() if alt.degrees >= 0: print('alt: ', alt, 'degrees (above the horizon)') else: print('alt: ', alt, 'degrees (below the horizon)') print('az: ', az, 'degrees around the horizon from north')

All you really need to know is that the moon is rotating and one day on the moon is one month long.

The axial tilt of the moon is 1.5 degrees, so there are no significant seasons.

The path of the sun is (close to) a great circle in the sky. And is much like the path of sun on the Equinox on Earth. It rises, takes 7.4 days to reach the Meridian (at which point its altitude is equal to 90-latitude) and then it slowly sets over another 7.4 days. It is then dark until the sun rises again. The whole period takes one month, 29.5 days

If you need greater accuracy (if you want to point a telescope at the sun, not just a solar panel) you would need to account for the axial tilt, which is tricky because the moon's orbit is complex and non-Keplarian.

You don't need to account for the motion of the moon around the Earth. The parallax is not enough to invalidate the calculation of the position, for the sake of pointing a solar panel. So just treat the moon as a slowly spinning body with almost not axial tilt and forget about the Earth.

The prime meridian on the moon is the meridian facing Earth. On the Prime meridian the sun culminates at full moon

If you are 90degrees East then the sun will culminate 1/4 month earlier and 90degrees West, then 1/4 month later.


Astronomy for Beginners 6: Lunar Eclipses

When the Moon eclipses the Sun, its shadow follows a narrow track across the Earth’s surface and few people see what happens but when the Earth’s shadow falls on the Moon, it can be seen from anywhere on the hemisphere facing the Moon at the time.

In the early part of the eclipse, often there’s little or nothing to be seen. That’s because the Sun shows as a disc half a degree across, and it takes time for the Earth to cover it. During that time, from the Moon, the Sun would be seen only partly eclipsed. This outer part of the Earth’s shadow is known as the penumbra. From within the inner cone, the umbra, the Sun would seem to be completely eclipsed. The curved edge of the umbra, as it sweeps across the Moon, helped to convince the ancient Greeks that the world must be round.

As it happens, the Moon and the Sun appear almost the same size from here, and that’s why solar eclipses are so dramatic when the outer atmosphere of the Sun flashes into view. (It took quite a long time to establish that it was the Sun’s atmosphere and not the Moon’s.) But from the Moon, the Earth has four times the apparent size of the Sun – another reason why lunar eclipses are more frequent and last longer.

Nobody has seen a lunar eclipse from a lunar viewpoint, though artists have been fascinated by the prospect for a long time. One of the earliest pieces of astronomical art I know is the colour page in the 19th century book “The Moon”, by Naysmith & Carpenter, showing the red-rimmed Earth eclipsing the Sun. The late Chesley Bonestell had several paintings on this theme, and it had been hoped that they could be compared with the reality by the camera on the Apollo 15 Lunar Rover, after the astronauts returned to Earth. Unfortunately contact was lost before the due eclipse occurred – the British artist David Hardy painted the Rover being driven away by a mocking alien.

Nevertheless we have one ‘picture’ of the phenomenon: compiled with some difficulty by a sensor on the unmanned spacecraft Surveyor 3 before manned landings on the Moon. The surprising thing was that the Earth wasn’t surrounded by a uniform ring of light – there were breaks in it, like the ‘Bailly’s Beads’ effect caused by mountains on the rim of the Moon during eclipses seen from here. Earth has no mountains of such size in relation to its diameter, but careful checking revealed that the breaks in the ring coincided with masses of cloud, on the rim of the Earth seen from the Moon.

What this means is that we can never be entirely sure what we’re going to see in a lunar eclipse. How soon the penumbral effect will become visible, and how dark the umbra will be, depends very much on the clouds round the sunrise and sunset limbs of the Earth at the time.

Clouds have another marked effect on eclipses, as far as we’re concerned. Back in my schooldays, before Luna III showed us the far side of the Moon for the first time, I was brought up on a poem – attributed to a servant of a poet, in the 30s, by Patrick Moore – which ran:

“Oh Moon, lovely Moon, with the beautiful face,

Careering along through the bound’ries of space

Whenever I see you, I think in my mind,

Shall I ever, oh ever, behold thy behind?”

Not often quoted nowadays, when the Farside has been thoroughly mapped. But one night back then, while waiting out an eclipse in which the clouds never broke at all, I came up with my own version.


Where is the sun relative to my lunar rover? - Astronomy

Is the flag that the astronauts left still on the moon? If so can it be seen by using a telescope? What about the lunar rover? Can we use the Hubble Space Telescope to see anything left behind by the astronauts?

Yes, the flag is still on the moon, but you can't see it using a telescope. I found some statistics on the size of lunar equipment in a Press Kit for the Apollo 16 mission. The flag is 125 cm (4 feet) long, and you would need an optical wavelength telescope around 200 meters (

650 feet) in diameter to see it. The largest optical wavelength telescope that we have now is the Keck Telescope in Hawaii which is 10 meters in diameter. The Hubble Space Telescope is only 2.4 meters in diameter - much too small!

Resolving the larger lunar rover (which has a length of 3.1 meters) would still require a telescope 75 meters in diameter.

Even barely resolving the lunar lander base, which is 9.5 meters across (including landing gear), would require a telescope about 25 meters across. And in reality you would want a couple (or a few) resolution elements across the object so that it's possible to identify it. (Otherwise it'll look like a one pixel detection, not an image, and I don't think people would be convinced by a couple pixels!) In addition, with a ground based telescope, you have to deal with distortion by the atmosphere as well, so you'll probably want something considerably larger than 25 meters if you want a good, believable, image of the lander. We don't have anything that big built yet! So there's really no way to image equipment left behind by the astronauts with current telescope technology.

More details for the mathematically inclined: How did I calculate this stuff? Well, here's the procedure. Let's take the case of Hubble and find out what the smallest thing it can see on the surface of the Moon is.

  1. Resolution (in radians) = (wavelength)/(telescope diameter) or R= w/D. This is a formula from optics.
  2. So for Hubble we know that the telescope diameter is 2.4 meters (it's not very big - it had to fit into the Shuttle.) Also, we know that visible wavelength light is in the range 400-700 nanometers. I'll use 600 nm, because it's somewhere in the middle and I've used it before for this calculation.
  3. If you use all units of meters and do R= (600e -9 )/(2.4) = 2.5e -7 . Well, that gives us the resolution of Hubble in radians which isn't too intuitive, but we can convert to meters on the surface of the Moon.
  4. To find the spatial extent that 2.5e -7 radians is at the distance of the moon, set up a triangle between Earth and the Moon, where R is the angle in radians that we calculated, x is the side opposite angle R which corrosponds to the object on the moon, and the adjacent side is the Earth-Moon distance. Then you have Tangent(R)=x/(distance Moon). The distance to the moon is 384,400 km. So converting to meters again and plugging in R and dmoon will give you a size in meters of the smallest size thing HST can see.
  5. When you do this you get 96.1 meters (315 feet). The astronauts didn't leave anything this big! If you look at this HST image of the Moon you can see that they say "Hubble can resolve features as small as 280 feet across." I think they used 500 nm as their wavelength instead of 600 nm, but it's the same order of magnitude as what we got here. So there's no way HST can see anything humans left behind. HST can do a good job of studying large-scale geology, like craters, which is what the images were of. People and their stuff are just really small on a planetary scale!

Update from Ann: It's still the case that the relatively small telescopes we have on Earth, and orbiting Earth, can't see these tiny features on the Moon. But in 2009 NASA launched the Lunar Reconnaissance Orbiter (LRO) probe to orbit the Moon, study the landscape in detail, and characterize the environment (mostly focused on checking for radiation, with which future astronauts would have to contend).

In addition to carrying out this scientific mission, LRO was able to take images of the Apollo landing sites (for the Apollo 11, 12, 14, 15, 16, and 17 missions) and could identify the flags and other equipment. Read more about that here or here, and check out NASA's multimedia image archive from LRO including this stunning image of the Apollo 11 site.


SOFIA discovers water on sunlit surface of moon

This illustration highlights the Moon’s Clavius Crater with an illustration depicting water trapped in the lunar soil there, along with an image of NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA) that found sunlit lunar water. Credit: NASA

NASA's Stratospheric Observatory for Infrared Astronomy (SOFIA) has confirmed, for the first time, water on the sunlit surface of the Moon. This discovery indicates that water may be distributed across the lunar surface, and not limited to cold, shadowed places.

SOFIA has detected water molecules (H2O) in Clavius Crater, one of the largest craters visible from Earth, located in the Moon's southern hemisphere. Previous observations of the Moon's surface detected some form of hydrogen, but were unable to distinguish between water and its close chemical relative, hydroxyl (OH). Data from this location reveal water in concentrations of 100 to 412 parts per million—roughly equivalent to a 12-ounce bottle of water—trapped in a cubic meter of soil spread across the lunar surface. The results are published in the latest issue of Nature Astronomy.

"We had indications that H2O—the familiar water we know—might be present on the sunlit side of the Moon," said Paul Hertz, director of the Astrophysics Division in the Science Mission Directorate at NASA Headquarters in Washington. "Now we know it is there. This discovery challenges our understanding of the lunar surface and raises intriguing questions about resources relevant for deep space exploration."

As a comparison, the Sahara desert has 100 times the amount of water than what SOFIA detected in the lunar soil. Despite the small amounts, the discovery raises new questions about how water is created and how it persists on the harsh, airless lunar surface.

Water is a precious resource in deep space and a key ingredient of life as we know it. Whether the water SOFIA found is easily accessible for use as a resource remains to be determined. Under NASA's Artemis program, the agency is eager to learn all it can about the presence of water on the Moon in advance of sending the first woman and next man to the lunar surface in 2024 and establishing a sustainable human presence there by the end of the decade.

SOFIA's results build on years of previous research examining the presence of water on the Moon. When the Apollo astronauts first returned from the Moon in 1969, it was thought to be completely dry. Orbital and impactor missions over the past 20 years, such as NASA's Lunar Crater Observation and Sensing Satellite, confirmed ice in permanently shadowed craters around the Moon's poles. Meanwhile, several spacecraft—including the Cassini mission and Deep Impact comet mission, as well as the Indian Space Research Organization's Chandrayaan-1 mission—and NASA's ground-based Infrared Telescope Facility, looked broadly across the lunar surface and found evidence of hydration in sunnier regions. Yet those missions were unable to definitively distinguish the form in which it was present—either H2O or OH.

"Prior to the SOFIA observations, we knew there was some kind of hydration," said Casey Honniball, the lead author who published the results from her graduate thesis work at the University of Hawaii at Mānoa in Honolulu. "But we didn't know how much, if any, was actually water molecules—like we drink every day—or something more like drain cleaner."

SOFIA offered a new means of looking at the Moon. Flying at altitudes of up to 45,000 feet, this modified Boeing 747SP jetliner with a 106-inch diameter telescope reaches above 99% of the water vapor in Earth's atmosphere to get a clearer view of the infrared universe. Using its Faint Object infraRed CAmera for the SOFIA Telescope (FORCAST), SOFIA was able to pick up the specific wavelength unique to water molecules, at 6.1 microns, and discovered a relatively surprising concentration in sunny Clavius Crater.

"Without a thick atmosphere, water on the sunlit lunar surface should just be lost to space," said Honniball, who is now a postdoctoral fellow at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "Yet somehow we're seeing it. Something is generating the water, and something must be trapping it there."

Several forces could be at play in the delivery or creation of this water. Micrometeorites raining down on the lunar surface, carrying small amounts of water, could deposit the water on the lunar surface upon impact. Another possibility is there could be a two-step process whereby the Sun's solar wind delivers hydrogen to the lunar surface and causes a chemical reaction with oxygen-bearing minerals in the soil to create hydroxyl. Meanwhile, radiation from the bombardment of micrometeorites could be transforming that hydroxyl into water.

How the water then gets stored—making it possible to accumulate—also raises some intriguing questions. The water could be trapped into tiny beadlike structures in the soil that form out of the high heat created by micrometeorite impacts. Another possibility is that the water could be hidden between grains of lunar soil and sheltered from the sunlight—potentially making it a bit more accessible than water trapped in beadlike structures.

For a mission designed to look at distant, dim objects such as black holes, star clusters, and galaxies, SOFIA's spotlight on Earth's nearest and brightest neighbor was a departure from business as usual. The telescope operators typically use a guide camera to track stars, keeping the telescope locked steadily on its observing target. But the Moon is so close and bright that it fills the guide camera's entire field of view. With no stars visible, it was unclear if the telescope could reliably track the Moon. To determine this, in August 2018, the operators decided to try a test observation.

"It was, in fact, the first time SOFIA has looked at the Moon, and we weren't even completely sure if we would get reliable data, but questions about the Moon's water compelled us to try," said Naseem Rangwala, SOFIA's project scientist at NASA's Ames Research Center in California's Silicon Valley. "It's incredible that this discovery came out of what was essentially a test, and now that we know we can do this, we're planning more flights to do more observations."

SOFIA's follow-up flights will look for water in additional sunlit locations and during different lunar phases to learn more about how the water is produced, stored, and moved across the Moon. The data will add to the work of future Moon missions, such as NASA's Volatiles Investigating Polar Exploration Rover (VIPER), to create the first water resource maps of the Moon for future human space exploration.

In the same issue of Nature Astronomy, scientists have published a paper using theoretical models and NASA's Lunar Reconnaissance Orbiter data, pointing out that water could be trapped in small shadows, where temperatures stay below freezing, across more of the Moon than currently expected. T

"Water is a valuable resource, for both scientific purposes and for use by our explorers," said Jacob Bleacher, chief exploration scientist for NASA's Human Exploration and Operations Mission Directorate. "If we can use the resources at the Moon, then we can carry less water and more equipment to help enable new scientific discoveries."


Where is the sun relative to my lunar rover? - Astronomy

Observations from HST and the Kepler space telescope have provided evidence for the first moon discovered orbiting a planet outside of our solar system. The discovery was announced on 03 October 2018. The moon may be the size of Neptune, orbiting a planet several times the mass of Jupiter with the designation Kepler-1625b. More.

Heliophysics

The Voyager 2 became the second spacecraft (the first was Voyager 1) to escape the heliosphere and enter insterstellar space. More.

The Parker Solar Probe made its first perihelion pass on 05 November 2018, coming within 25 million km of the Sun. The probe will orbit the Sun over the course of the next seven years, ultimately coming closer than 7 million km from the Sun's surface.

Lunar and Planetary Science

On June 7 at 17:35 UT (1:35 p.m. EDT), the NASA Juno spacecraft passed within about 1000 km of the surface of Ganymede, the largest moon in the solar system.

NASA has selected two new missions to Venus as part of its Discovery program, an atmospheric probe: DaVinci+ (Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging), and an orbiter: VERITAS (Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy), to launch in 2028 to 2030. For more detail see the NASA Press Release.


Where is the sun relative to my lunar rover? - Astronomy

The Moon has been theobject of awe and fascination since our humanoid ancestors first looked up into the sky. Here are some questions about the Moon and our links with it. You have three choices to complete each statement about our satellite. You can then check your answers, and also find out a bit more.


  1. A lunar eclipse occurs when: (A) the Moon is lined up between the Sun and the Earth (B) when a full Moon is nearest to the Earth (C) the Earth is directly between the Sun and the Moon
  2. The phase of the Moon that is also known as the second quarter is: (A) half Moon (B) gibbous Moon (C) full Moon
  3. We always see the same side of the Moon because the Moon: (A) doesn't turn on its axis (B) the Sun's gravity pulls strongly on it (C) takes the same amount of time to orbit as it does to turn once on its axis
  4. The length of a month counted from new Moon to the next new Moon (a synodic month) is: (A) 28.5 days (B) 29.5 days (C) 30.5 days
  5. The first image ever seen of the far side of the Moon came from: (A) NASA's Surveyor 1 (B) the Soviet Luna 3 (C) NASA's Ranger 7
  6. The Moon's orbit isn't circular. The point where the Moon is at its closest to the Earth is called: (A) apogee (B) perigee (C) aphelion
  7. The dark areas on the face of the Moon (the lunar maria) are: (A) basaltic rock that formed in ancient craters (B) dried-up beds of ancient seas (C) areas darkened by impact debris from the Late Heavy Bombardment
  8. The number of Apollo missions that landed people on the Moon was: (A) 2 (B) 4 (C) 6
  9. Neil Armstrong was the first man on the Moon. The last one (so far!) was: (A) Gene Cernan (B) Harrison Schmitt (C) David Scott
  10. The name of the Chinese lunar rover was: (A) Chang'e (Moon goddess) (B) Heng-O (mother of heavens) (C) Yutu (jade rabbit)

1. A lunar eclipse occurs when: (C) the Earth is directly between the Sun and the Moon.
It's the Earth's shadow that we see on the Moon during a lunar eclipse. It can only occur when the Earth is precisely aligned with a full Moon.

2. The phase of the Moon that is also known as the second quarter is: (C) full Moon.
This diagram shows the Moon phases. Follow the diagram from new Moon counterclockwise to half Moon – that is the first quarter Moon. Another quarter circle takes you to the second quarter Moon which is the full Moon.

3. We always see the same side of the Moon because the Moon: (C) takes the same amount of time to orbit as it does to turn once on its axis.
This little animation shows the Moon in motion. The Moon on the left orbits Earth keeping the same side facing Earth. It rotates on its axis once in the time it takes for one orbit. The Moon on the right shows what would happen if it didn't rotate as it orbited. Watch it carefully, and you can see that all parts of the Moon would at some time be visible from somewhere on Earth.

3. The length of a month counted from new Moon to the next new Moon (a synodic month) is: (B) 29.5 days.
The Moon takes 27.5 days to get around the Earth. However as it does this, the Earth is moving. Therefore the Moon needs some extra time to get back to its original position with respect to the Earth and the Sun to complete its cycle of phases.

4. The first image ever seen of the far side of the Moon came from: (B) the Soviet Luna 3.
Here is humanity's first look at the far side of the Moon. The quality isn't great, but it's good enough to show that there isn't much cratering on the far side. That was quite a surprise.

5. The Moon's orbit isn't circular. The point where the Moon is at its closest to the Earth is called: (B) perigee.
Apogee is the most distant point in the lunar orbit. Aphelion is the most distant point in an orbit of the Sun, so it doesn't apply to the Moon.

6. The dark areas on the face of the Moon (the lunar maria) are: (A) basaltic rock that formed in ancient craters.
A heavy bombardment left the giant craters, and later in the Moon's history they were filled with lava which solidified into a dark basaltic rock.

7. The number of Apollo missions that landed people on the Moon is: (C) 6.
Many people aren't aware that there were so many manned missions to the surface of the Moon. There were six successful ones: Apollo 11, 12, 14, 15, 16 and 17. Apollo 13 made it into lunar space, but had suffered an explosion that left them barely able to make it home alive.

8. Neil Armstrong was the first man on the Moon. The last one (so far!) was: (A) Gene Cernan.
Cernan was the Commander of Apollo 17. Harrison Schmitt was on the Moon with Cernan, but Cernan followed him into the lunar module.

10. The name of the Chinese lunar rover was: (C) Yutu (jade rabbit).
Chang'e is Chinese Lunar Exploration Program. Jade Rabbit's visit to the Moon was the first soft landing on the Moon in four decades. The program had a big following in China (and elsewhere), but technical problems left the mission incomplete. Provided with a Twitter account, Yutu's final tweet was “Good night, planet Earth. Good night, humanity.”

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Chinese space rover begins first surface exploration of moon's far side

BEIJING — China’s Chang’e-4 lunar lander touched down on the far side of the moon Thursday morning Beijing time, the latest milestone marking the nation’s determination to become a global leader in space exploration.

Chinese scientists have already declared China’s ambitions to establish a manned moon base and to send nuclear-powered rockets into space in future decades to colonize and exploit space.

No nation has ever landed a lunar lander on the far side of the moon, a mission complicated by the fact that the moon blocks direct communications with Earth. China used a relay satellite, Queqiao, to send transmissions to scientists.

Chang’e-4, carrying a 300-pound lunar rover with probes and spectrometers, touched down in the Von Karman Crater in the South Pole-Aitken Basin, according to the China National Space Administration, which published a color photograph of the moon’s smooth surface, a crater and the dark horizon beyond.

The moon landed at 10:26 a.m. on the planned landing site, “lifting the mysterious veil” of the far side of the moon, the administration said in a statement, “which opened a new chapter in human lunar exploration.”

The state-owned Global Times said it marked a major step toward the establishment of a Chinese manned lunar base — and toward deep space exploration.

Chang’e-4 was launched from Xichang satellite launch station in Sichuan province, southern China, on Dec. 8. A forerunner, Chang'e-3, landed on the moon in 2013, making China the third country after the Soviet Union and the United States to soft land a spacecraft — meaning the craft would not be destroyed in the landing — on lunar soil. However, its lunar rover malfunctioned soon after landing and was unable to move after its second night, although it continued to send information to Earth.

Later this year, China is expected to launch another lunar lander, Chang’e-5, with its own rover to bring back samples.

The six-wheeled lunar rover will probe the lunar surface and transmit photographs to Earth. The mission also encompasses a biological experiment, to assess whether seeds can germinate and silkworm larvae can hatch and grow in a sealed container containing nutrients, water and air.

Chang’e-4 also carries German and Swedish research equipment to study radiation and lunar wind. It is also expected to experiment with conducting low frequency radio astronomy observations free of interference from Earth.

“The far side of the moon is a rare quiet place that is free from interference of radio signals from Earth. This probe can fill the gap of low-frequency observation in radio astronomy and will provide important information for studying the origin of stars and nebula evolution,” mission spokesman Yu Guobin told New China News Agency.

Secrecy around China’s space program is intense, and news from Chinese authorities about Chang’e-4 was limited in the lead-up to the landing, perhaps because of setbacks in past missions.

Global media attention on China’s space program has often focused on those setbacks rather than the steady progress being made. In October China’s first private rocket failed to reach orbit, and earlier in the year one of its two orbiting space stations, Tiangong-1, crashed uncontrolled to Earth. The previous year two Long March rocket launches failed. However, China completed dozens of successful rocket launches last year.

Independent space expert Namrata Goswami, writing in the Diplomat, said Chang’e-4 had underscored China’s seriousness about meeting deadlines and targets for space travel, noting that Chinese space scientists set the 2018 deadline for the far-side lunar landing years ago.

“This meeting of deadlines set has been the trajectory of China’s unmanned (1999) and manned space missions (2003), its space stations, the Tiangong 1 (2011) and Tiangong 2 (2016), as well as the indigenously built cargo spacecraft, the Tianzhou 1 (2016), which docked with the Tiangong 2,” she wrote.

“Significantly, China’s ambitions for the moon and outer space have only been growing, to include ambitions of a Chinese research base on the moon, as well as developing bio-regenerative life support systems to ensure that humans can settle and survive in lunar conditions.”

She said China’s ambition was to be able to “set the rules of the game in outer space” by establishing a long-term human presence.

In May, eight Chinese volunteer students concluded a year-long test of a bio-regenerative life support system at Beihang University, an astronautics and aeronautics university in Beijing. They marked a record for human habitation in an enclosed system with recycled water, food and air — a crucial facility for lunar habitation. The students grew food including wheat, potatoes, carrots, beans and onions, and ate high-protein mealworms.

Underscoring the growing strategic rivalry between the U.S. and China, President Trump has announced plans for a military space force. Meanwhile NASA announced plans in 2017 to return to the moon and to establish a long-term manned base on the moon “for a sustained period of exploration and use,” and as a possible launch pad for a future manned mission to Mars. NASA’s eighth spacecraft landing on Mars was in November.

But last month two NASA Apollo mission veterans warned of the need for funding, technology and a cohesive, consistent plan, complaining that successive administrations had failed to fund NASA adequately.

China’s rapid expansion of its space program has the Pentagon concerned, although China has insisted it has no plans to militarize space. In August, a Pentagon report on China’s military capabilities warned of China’s advance in space exploration and its capacity to use space technology for military and surveillance purposes, including the potential to knock out opponents’ satellites. China has already tested anti-satellite missiles. The Pentagon predicted China would have a crewed orbiting space station by 2025. China is also swiftly developing its own global satellite navigation system, Beidou.

The lunar lander is just part of an ambitious, carefully planned, long-term space exploration plan that includes colonizing and commercially exploiting the solar system and beyond.

After unmanned rocket launches, China became the third nation to independently send a human into space in 2003 (after Russia and the United States). It has plans to de-orbit its second space station and launch a third, which will be manned. Its manned and robotic missions aim to build its technological prowess and research, and eventually develop the capacity to send astronauts into space for longer periods. From there China plans better space vehicles, deep space exploration and exploitation of resources.

Chinese officials rarely discuss the nation’s expansive space ambitions, but in late 2017 the state-owned People’s Daily spelled out the plans of the China Academy of Launch Vehicle Technology, China’s rocket manufacturer, including plans to establish a fleet of nuclear-powered space shuttles by the 2040s for regular space flights to other planets, in order to commercially exploit resources.

In the nearer term, it aims to catch up to American rocket technology, launch a Mars probe and launch a reusable shuttle by 2025 to begin space tourism.

China’s space exploration is a key part of its Made In China 2025 program, which involves attaining global leadership in space travel by the middle of the century. Chinese officials and state media have stopped using the term lately, after it was censored by authorities last year over concerns that it was antagonizing the Trump administration as trade tensions between the two nations mounted.

Although hopes are mounting that the two nations may reach a deal to end the trade war — with tariffs on billions of goods on both sides — analysts do not expect China to give up its core aspiration to become a global leader in strategic technology such as rockets, robots and artificial intelligence.


Comments

According to 'Space Reference.org', 'Snoopy' tracks alot nearer to earth than 35 million kilometres, and surprising that it hasn't been found before. Power of the craft must have expired along time ago, or could they power it up?

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David Dickinson Post Author

Correct 35 million (miles) is the object's current distance, trailing Earth. It laps us in 2037. The suspect object was just discovered during a close pass by Earth in 2018.

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I have some Gemini era flight test article nicad cells which still take and hold a charge. I know of a friend who had a nicad cell device recently which he'd not powered on for 25 years start up.

It's possible with good quality space rated stuff and some really good cells that it would hold a charge.

however with all older equipment there are a lot of other electronic components which would not have aged well even if on earth that would pose a problem.


Far side find

Yutu 2 has been making its way west from the Chang'e 4 landing site, which is situated within the roughly 110-mile-wide (180 kilometers) Von Kármán Crater. On July 28, during Lunar Day 8 of the mission, the rover came across a crater about 6.5 feet (2 meters) in diameter containing a material deemed to have an unusual color and luster.

The initial discovery was made by a Yutu 2 drive team member checking images from the rover's main camera. The drive team consulted lunar scientists, resulting in the decision to postpone plans to have Yutu 2 continue west and instead order the rover to check out the strange material.

Our Space, which announced the findings on Aug. 17, used the term "胶状物" ("jiao zhuang wu"), which can be translated as "gel-like." This description sparked wide interest and speculation among lunar scientists.

The first images of the crater and its contents came from an obstacle-avoidance camera. These images did not, however, have a high resolution, and they included colored shapes likely related to Yutu 2's science instruments, further obscuring the material.

Yutu 2 made a number of approaches to the material to analyze it using the rover's Visible and Near-Infrared Spectrometer (VNIS), which detects light that is scattered or reflected off materials to reveal their makeup.

The small adjustments in orientation and roving tested the rover and its team, with the danger that Yutu 2 could fall into and become stuck in the crater. The movement of the sun across the sky also altered shadowing and affected results.

A second set of measurements, taken in August, was apparently more successful than the first, but results from VNIS have not been announced.

Yutu 2 has driven a total of 950 feet (289 m) across 10 lunar days. Yutu 2 and the Chang'e 4 lander power down to hibernate during the roughly two-week-long lunar nights, when temperatures can drop to as low as minus 310 degrees Fahrenheit (minus 190 degrees Celsius).

Sunrise over the landing site in Von Kármán Crater occurred Oct. 21 Yutu 2 will wake for Lunar Day 11 on Oct. 22, and the lander will do so about 24 hours later.


Russian lunar rover found: 37-year-old space mystery solved

A researcher from The University of Western Ontario has helped solve a 37-year old space mystery using lunar images released March 15 by NASA and maps from his own atlas of the moon.

Phil Stooke, a professor cross appointed to Western's Departments of Physics & Astronomy and Geography, published a reference book on lunar exploration in 2007 entitled, "The International Atlas of Lunar Exploration."

On March 15, images and data from NASA's Lunar Reconnaissance Orbiter (LRO) were posted. The LRO, scheduled for a one year exploration mission about 31 miles above the lunar surface, will produce a comprehensive map, search for resources and potential safe landing sites and measure lunar temperatures and radiation levels.

Using his atlas and the NASA images, Stooke pinpointed the exact location of the Russian rover Lunokhod 2, discovering tracks left by the lunar sampler 37 years ago after it made a 35-kilometre trek. The journey was the longest any robotic rover has ever been driven on another celestial body.

As soon as the NASA photos were released, scientists around the world, including Stooke, began work to locate the rover. Stooke set up a searchable image database and located the photograph he needed, among thousands of others.

"The tracks were visible at once," says Stooke. "Knowing the history of the mission, it's possible to trace the rover's activities in fine detail. We can see where it measured the magnetic field, driving back and forth over the same route to improve the data. And we can also see where it drove into a small crater, and accidentally covered its heat radiator with soil as it struggled to get out again. That ultimately caused it to overheat and stop working. And the rover itself shows up as a dark spot right where it stopped."

The find, he adds will mean that older maps published by Russia will now need to be revised.

Stooke says that NASA scientists have used his atlas in both preparation and data recovery.

His next project is a similar volume on Mars exploration which will include the best maps of the moons of Mars.

Story Source:

Materials provided by University of Western Ontario. Note: Content may be edited for style and length.


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