Category: Moon

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Chandrayaan-1, India’s first unmanned spacecraft mission to moon, successfully entered lunar orbit on November 8. The spacecraft fired its engines to reduce velocity and enable the Moon’s gravity to capture it; engines were fired for 817 seconds when Chandrayaan-1 was about 500 km away from the moon. Next up for the spacecraft will be to reduce the height of its lunar orbit to about 100 km. Then, on Nov. 14th or 15th, the Moon Impact Probe (MIP) will be launched, and crash into the Moon’s surface (more about the MIP below). If you enjoy watching animations and want to see exactly how the spacecraft attained its lunar orbit, here’s a few animations for you:

A simple animation of how the spacecraft went from its spiraling elliptical orbit around Earth to its now spiraling elliptical orbit around the moon can be found on the India Space Agency’s site. (Sorry, the file was to big to insert here.)

Another quite large animation that was created by Doug Ellison (of UnmannedSpaceflight.com) shows how the X-ray Spectrometer aboard Chandrayaan-1 will work. This one takes a long time to download, but the wait is well worth it: the animation is spectacular.

Here’s a video that shows an animation of the entire mission; again, some great animation here. Enjoy.

The spacecraft is now orbiting the moon in an elliptical orbit that passes over the polar regions of the moon. The nearest point of this orbit (perigee) lies at a distance of about 504 km from the moon’s surface while the farthest point (apogee) lies at about 7502 km. Currently, Chandrayaan-1 takes about 11 hours to orbit the moon.

The MIP carries three instruments:

Radar Altimeter – measures the altitude of the probe during descent and for qualifying technologies for future landing missions.

Video Imaging System – acquires close range images of the surface of the Moon during descent. The video imaging system consists of analog CCD camera.

Mass Spectrometer measures the constituents of lunar atmosphere during descent.

Source: ISRO

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Following the fifth and final orbit raising maneuver which put Chandrayaan-1 closer to the moon, the spacecraft snapped the first picture of its final destination. This clear, crisp image of the moon While the images are still being processed and are not available yet, mission managers says the images bode well for spacecraft’s mission to map the entire moon’s surface with its Terrain Mapping Camera. And all systems are go for the final maneuver on November 8, which will put Chandrayaan-1 in lunar orbit.

After launch on October 22, the spacecraft was first injected into an elliptical 7-hr orbit around Earth, at 255 km from Earth at perigee (its closest point) and 22,860 km away at apogee, its farthest point. After five engine firings, Chandrayaan-1 has spiraled outwards in increasingly elongated ellipses around Earth, until it reached its lunar transfer orbit on November 4.

In the final maneuver, engineers fired the spacecraft’s 440 Newton liquid-fuel propelled engine for about two and a half minutes. The lunar transfer orbit’s farthest point from Earth is about 380,000 km.

On November 8, as it nears the moon, the spacecraft’s engine will be fired again to slow the spacecraft, allowing the moon’s gravity to capture it, and then it will go into an initial elliptical orbit around the moon. A group of engineers from JPL are assisting the engineers from India, acting as experienced back-up for the “first-time-flyers” from India. And everything has gone smoothly thus far.

The spacecraft will make observations from the initial orbit, and then the orbit will be lowered a 100 km circular polar orbit. Following this, the Moon Impact Probe (MIP) will be ejected, impacting the lunar surface. Then the main mission will begin with Chandrayaan-1 exploring the moon from orbit with its array of instruments for two years.

Source: Bharat Chronicle

After a successful maneuver early today (October 26, 2008), the Chandrayaan-1 spacecraft has crossed the 150,000 km distance mark from Earth, officially entering deep space, on course for the moon. This was the third orbit raising maneuver of the mission. The spacecraft’s 440 Newton liquid engine was fired for about nine and a half minutes, beginning at 07:08 IST. With this, Chandrayaan-1 entered a much higher elliptical orbit around the Earth. The apogee (farthest point from Earth) of this orbit lies at 164,600 km while the perigee (nearest point from Earth) is at 348 km. In this orbit, Chandrayaan-1 takes about 73 hours to go round the Earth once.

To compare, Chandrayaan’s initial orbit had a perigee of 255 km and an apogee of 22,860 km, with about a 6.5-hour period. After the second boost from its engines, Chandrayaan raised its apogee to 37,900 kilometers, and increased its orbit period to 11 hours.

Engineers from the Jet Propulsion Laboratory are also providing backup navigation assistance to the Indian Space Agency in Bangalore, India, by helping to track the flight dynamics. The antennas of the Indian Deep Space Network at Byalalu are being used for tracking and communicating with Chandrayaan-1 spacecraft in its high orbit. From the image below, you can see how additional orbit raising maneuvers in the next few days will take Chandrayaan-1 towards the Moon, and then into lunar orbit. Currently, the spacecraft is scheduled to reach lunar orbit on November 8.

Source: ISRO

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It’s been a long-held belief that the Moon is hiding significant quantities of water ice, safe from the Sun’s ablative effects inside shady craters. One such crater is called Shackleton at the lunar South Pole and previous Moon missions have indicated it might hold a large reservoir of ice for all the water needs of future Moon colonists. Alas, the Japanese lunar mission Kaguya (or the Selenological and Engineering Explorer – “SELENE”) has taken a peek into the crater to find… nothing. At least, it hasn’t spotted any significant quantities of surface ice. So where does this leave future lunar colonies?

In 1994, the US Clementine lunar orbiter (a joint venture between NASA and the Ballistic Missile Defense Organization) carried out the “Bistatic Radar Experiment” which involved bouncing radio signals from the probe’s transmitter from the lunar poles. The reflected signal was then received by the Deep Space Network antennae on Earth. Scientists deduced from the reflected signal that volatile ices were present in the lunar regolith, most probably water ice. However, this claim was disputed after a similar experiment was done using the Arecibo radio telescope in Puerto Rico. This time, radio signals were reflected from regions on the Moon bathed in sunlight (where it would be impossible for water ice to survive) and identical results to the Clementine mission were found.

NASA’s 1998 Lunar Prospector also had mixed results. Using its Neutron Spectrometer (NS) instrument, the probe had detected large quantities of water, leading NASA to make the estimate that 3 billion metric tons of water ice was located at or near the surface of the Moon in its polar regions. However, when the mission ended in 1999, the Lunar Prospector was deliberately crashed into a crater in the lunar South Pole in the hope of kicking up a plume of lunar surface material and detecting water ice from Earth. Unfortunately, no water was discovered. (Out of interest, the Lunar Crater Observation and Sensing Satellite, set for launch in April 2009, has a similar suicidal goal to put a divot in the Moon.)

Now, using the Japanese lunar mission Kaguya, scientists have taken the opportunity to have a closer look into the Shackleton crater, the most likely candidate to have a supply of water ice shaded from the Sun. As there is no atmosphere (apart from some very tenuous outgassed chemicals), sunlight cannot be scattered into the bottom of the crater to illuminate its surface. However, scientists have taken images during lunar mid-summer when enough light is scattered off the crater’s upper inner wall to faintly brighten the darkness below.

Although it is very cold inside the crater (-183°C or -297°F), certainly ideal conditions to preserve ice, there is no visual evidence of any surface ice at all.

Although this isn’t great news for future lunar colonists, don’t pack up your Moon buggies quite yet. The Japanese team have concluded that although there is no visual brightening due to ice, water ice may be mixed in low quantities with the lunar dirt. Or there’s simply no ice in Shackleton crater. Either way, I wouldn’t suggest mounting a manned expedition to Shackleton any time soon…

Source: Space.com

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Chandrayaan-1, India’s first mission to the Moon, was successfully launched earlier this morning from the Satish Dhawan Space Centre (SHAR) in Sriharikota, India. The PSLV-C11 rocket lifted off at 02:52 Central European Summer Time (CEST). About 20 minutes later the spacecraft was , injected into a highly elongated orbit around the Earth. The spacecraft will reach the moon in about two weeks. It will take several days for the Chandrayaan-1 to reach its lunar transfer orbit, and then it will take about 5 days to reach the moon. Once the spacecraft is orbiting the moon, it will progressively lower its altitude through propulsive maneuvers to reach its final 100 km-high circular orbit.

At the earliest opportunity, the spacecraft will eject the ‘Moon Impact Probe’ to provide information about the lunar surface. The mission will then continue from orbit, with remote-sensing studies carried out by its 11 scientific instruments. Three of these instruments were provided by Europe (UK, Germany, Sweden) through ESA.

Sources: ESA,