Mapping magnetic anomalies.The Martian Chronicles on a Swedish instrument called SARA on board the ship: "SARA will also be able to study magnetic anomalies, presumably because the magnetic fields will change how the solar wind interacts with the surface."
"Magnetic anomaly" caught my attention because this is what begins the fuss in Arthur Clarke's famous novel "2001 A Space Odyssey". TMA it was called in the story - Tycho Magnetic Anomaly, because it was found in the Tycho region.What's the use of "Radioactive mapping"?Radioactive mapping is one of the things the mission will do. But what is it? And why do it?
The Martian Chronicles clarifies the purpose of the on board Bulgarian instrument that will do this job: "The whole goal is for this thing to get bombarded with radiation and see how much there is, what range of energies the particles have, and figure out how that dose might change for different locations on the moon. The Apollo astronauts were only out of Earth’s protective magnetic field for a few days, but for colonists spending months or years out there, it’s important to know how much radiation shielding they will need, and what type of radiation is the most dangerous."Detecting water ice.The Martian Chronicles on an on board Indian instrument called HEX: "a thick ice deposit would absorb x-rays that normally would be emitted to space, so by measuring changes in x-ray emission, HEX might be able to detect water ice."Chandrayaan-1 Project Director answers some questions on ship's trajectory.Technical details of trajectory to moon of Chandrayaan-1 spaceshipVia R Prasad's article titled "How Chandrayaan-1 is raised to higher orbits" in The Hindu newspaper of Madras. Article is based on correspondent's interaction with "M. Annadurai, Project Director of Chandrayaan-1". Click image above for full size original.
Why this multistage trajectory? Answer is, primarily, caution: "We could have done it [in] one shot, but there is a possibility of missing the moon. So we have adopted an incremental increase in the orbits’ perigee." I suppose "apogee" is meant, & "perigee" is a misquote.
Also, "There will be a need to correct the orbit once in two weeks to maintain a 100 km circular orbit" on moon. I guess at the end of its useful life - meaning propellant & fuel exhausted - it will simply fall somewhere on moon?
Why this multistage trajectory? Answer is, primarily, caution: "We could have done it [in] one shot, but there is a possibility of missing the moon. So we have adopted an incremental increase in the orbits’ perigee." I suppose "apogee" is meant, & "perigee" is a misquote.
Also, "There will be a need to correct the orbit once in two weeks to maintain a 100 km circular orbit" on moon. I guess at the end of its useful life - meaning propellant & fuel exhausted - it will simply fall somewhere on moon?
Related: Arthur Clarke's novel "Islands in the Sky" lightly touches upon the subject of human littering in space. A habit now when it doesn't cause much damage but a costly danger when space travel becomes common (because habits die hard). Not that ISRO is alone - everyone traveling to space seems to be doing it today.
Mr Annadurai answers several other questions too, including why fire at perigee & how moon capture will happen.
A related point: Reducing the speed - needed for capture by moon & lowering of orbit there - requires that "the orientation of the spacecraft is reversed — turned 180 degrees". This implies the craft is fitted with special orientation rockets that can fire simultaneously in more than one directions. I'd not thought of it; I guess it's needed by all craft that orbit earth too.Chandrayaan-1 is now on "Lunar Transfer Trajectory".Illustration accompanying the ISRO announcement that Chandrayaan spacecraft is now in Lunar Transfer Orbit after the fifth orbit raisingISRO announcement dated 4 November 2008: "The fifth and final orbit raising manoeuvre of Chandrayaan-1 spacecraft was successfully carried out today (November 4, 2008) morning at 04:56 am IST... With this, Chandrayaan-1 entered the Lunar Transfer Trajectory". Current orbital parameters: apogee = 380,000 km. Perigee not specified in the announcement. Click image for original size picture.
Mr Annadurai answers several other questions too, including why fire at perigee & how moon capture will happen.
A related point: Reducing the speed - needed for capture by moon & lowering of orbit there - requires that "the orientation of the spacecraft is reversed — turned 180 degrees". This implies the craft is fitted with special orientation rockets that can fire simultaneously in more than one directions. I'd not thought of it; I guess it's needed by all craft that orbit earth too.Chandrayaan-1 is now on "Lunar Transfer Trajectory".Illustration accompanying the ISRO announcement that Chandrayaan spacecraft is now in Lunar Transfer Orbit after the fifth orbit raisingISRO announcement dated 4 November 2008: "The fifth and final orbit raising manoeuvre of Chandrayaan-1 spacecraft was successfully carried out today (November 4, 2008) morning at 04:56 am IST... With this, Chandrayaan-1 entered the Lunar Transfer Trajectory". Current orbital parameters: apogee = 380,000 km. Perigee not specified in the announcement. Click image for original size picture.
