Chandrayaan-1 Enters Lunar Orbit

Flag Of India Is Planted On Moon

The Indian Space Research Organisation (ISRO) unmanned spaceship Chandrayaan-1 entered lunar orbit successfully, ISRO announced.

Then the spaceship ejected a lunar craft called the Moon Impact Probe that struck the surface of the moon to kick up dust that could be analyzed. As well, the probe took pictures of the lunar surface, according to ISRO.

And the probe planted the flag of India on the surface of the moon, a flag painted on the sides of the probe.

This Indian arrival on the moon comes as the United States once again sent another manned mission to low Earth orbit, with Space Shuttle Endeavour headed to the International Space Station. (Please see full story in this issue.)

The fully successful unmanned Indian mission to the moon also comes three-and-a-half decades after the last manned U.S. mission to the moon, Apollo 17. The United States won’t have another manned lunar mission until 2020 at the earliest, assuming development of the next-generation Orion-Ares spacecraft/booster system and Altair lunar lander proceeds on schedule.

From above the moon, Chandrayaan-1 also is taking pictures, including one taken over the polar region of the moon showing various-sized craters, including Moretus, a crater 72.7 miles (117 kilometers) wide.

Chandrayaan-1 swoops within roughly 124 miles from the surface of the moon at the lowest point in its orbit.

The liquid-fuel engine was fired when it was a bit more than 300 miles from the moon. That cut the spacecraft velocity, so the lunar gravitational field could capture Chandrayaan-1 into orbit.

The lowest point of the orbit was 313 miles from the moon, which Chandrayaan-1 circled every 11 hours.

Lunar orbit insertion was executed from the Chandrayaan-1 Spacecraft Control Centre at ISRO’s Telemetry, Tracking and Command Network at Bangalore, India. The performance of all the systems on board Chandrayaan-1 was registered as normal.

After that, the Chandrayaan-1 engine was fired for about 57 seconds, reducing the orbit low point to 124 miles from the lunar surface, while the farthest point remained unchanged at 4,662 miles.

Finally, ISRO began, in stages, to reduce the spacecraft altitude to about 62 above the surface of the moon, in a polar orbit.

The Moon Impact Probe (MIP) was then released to hit the lunar surface, after which the other instruments on board began to be turned on.

Chandrayaan-1 was launched Oct. 22 from the Indian spaceport at Satish Dhawan Space Centre SHAR, Sriharikota, India. The launcher placed the spacecraft in an elliptical orbit around Earth.

In past weeks, the Terrain Mapping Camera (TMC), one of the eleven scientific instruments of the spacecraft, was successfully operated to take pictures.

The probe, and the flag of India, were placed on the moon on the birthday of Pandit Jawaharlal Nehru, a former prime minister of India. It was the first time India placed a craft on the surface of the moon.

Weighing roughly 75 pounds (34 kilograms) at the time of its launch onboard Chandrayaan-1, the box-shaped MIP carried three instruments — a video imaging system, a radar altimeter and a mass spectrometer.

The video imaging system took pictures of the moon’s surface as MIP approached it. The radar altimeter was included to measure the rate of descent of the probe to the lunar surface. Such instruments are necessary for future lunar soft landing missions. And the mass spectrometer was for studying the extremely thin lunar atmosphere.

MIP’s 25-minute journey to the lunar surface began with its separation from Chandrayaan-1 spacecraft, followed by a series of automatic operations that began with firing its spin-up rockets after achieving a safe distance of separation from Chandrayaan-1.

Later, the probe slowed by firing its retro rocket and started its rapid descent towards the moon’s surface. Information from its instruments was radioed to Chandrayaan-1 by MIP. The spacecraft recorded this in its onboard memory for later readout. Finally, the probe had a hard landing on the lunar surface that terminated its functioning.

Two of Chandrayaan-1′s payloads – the Terrain Mapping Camera (TMC) and Radiation Dose Monitor (RADOM) – were switched on. Some eight remaining payloads are being switched on in the mission.

Chandrayaan-1 was launched Oct. 22, attained elliptical Earth orbit, then transferred to a lunar trajectory and orbit, entering lunar orbit Nov. 8, to begin a gradual lowering of the orbit so the spacecraft passed near the surface of the moon.

Further, the Lunar Laser Ranging Instrument (LLRI), one of the 11 scientific instruments (payloads) carried by Chandrayaan-1, was turned on yesterday as the spacecraft passed over the western part of the moon’s visible hemisphere.

Preliminary assessment of the data from LLRI by ISRO scientists indicates that the instrument’s performance is normal. LLRI sends pulses of infrared laser light towards a strip of lunar surface and detects the reflected portion of that light.

The instrument thus can very accurately measure the height of moon’s surface features. LLRI will be continuously taking 10 measurements per second on both day and night sides of the moon.

It provides topographical details of both polar and equatorial regions of the moon. Detailed analysis of the data sent by LLRI helps in understanding the internal structure of the moon as well as the way that celestial body evolved.

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