| 1. What Is Chandrayaan-1 |
|
| Chandrayaan-1 is a scientific investigation –
by spacecraft – of the Moon. The name Chandrayaan
means “Chandra- Moon , Yaan-vehicle”, –in
Indian languages (Sanskrit and Hindi) , – the lunar
spacecraft. Chandrayaan-1 is the first Indian planetary
science and exploration mission. |
|
| 2. When, and from where,
Chandrayaan-1 will be launched? |
|
| Chandrayaan-1 will be launched in early 2008 from Satish
Dhawan Space Centre at Sriharikota (SHAR), India. |
|
| 3. How long will it take
Chandrayaan-1 to get to Moon? |
|
| It will take about 5½ days for Chandrayaan-1 to get
to the Moon. |
|
| 4. How close to Moon will
Chandrayaan-1 come while orbiting the Moon? |
|
| Chandrayaan-1 spacecraft will be in a 100 km polar orbit
around the Moon. |
|
| 5. What are Chandrayaan'
s scientific goals? |
|
| The Chandrayaan-1 mission is aimed at high-resolution
remote sensing of the Lunar surface in visible, near Infrared,
low energy X-rays and high-energy X-ray regions. Specific
scientific goals are: |
|
 |
To prepare a three-dimensional atlas (with a high
spatial and altitude resolution of 5-10m) of both
near and far side of the moon. |
|
To conduct chemical and mineralogical mapping
of the entire lunar surface for distribution of
elements such as Magnesium, Aluminum, Silicon, Calcium,
Iron and Titanium with a spatial resolution of about
20 km and high atomic number elements such as Radon,
Uranium & Thorium with a spatial resolution of about
40 km. |
|
|
| By simultaneous photo geological and chemical mapping
we will be able to identify different geological units,
which will test the hypothesis for the origin and early
evolutionary history of the moon and help in determining
the nature of the lunar crust. |
|
| 6. What are the basic components
of the Chandrayaan-1 spacecraft? |
|
| The basic components of the chandrayaan-1 spacecraft
are |
|
|
The scientific payloads: the instruments that
will gather science data. |
|
The solar array that provides power to the spacecraft.
Chandrayaan also carries a battery that stores the
power generated by the solar array and feeds it
to other systems. |
|
The thrusters perform fuel burns to change the
spacecraft’s trajectory and attitude. |
|
The various functional requirements of the spacecraft
such as Attitude and Orbit Control, Command processing,
House keeping telemetry, Sensor data processing,
Thermal management, payload data handling operation,
duel gimbaled data transmission antenna pointing
, onboard mission management etc would be taken
care by the Bus Management Unit (BMU). |
|
The spacecraft also carries two star sensors and
inertial reference unit based on miniaturized gyros
providing absolute attitude. |
|
|
| 7. What are the scientific
instruments onboard Chandrayaan-1? |
|
| There are altogether eleven scientific instruments onboard
Chandrayaan-1 spacecraft. Five of them are Indian and
other six are from European Space Agency (3), NASA(2)
and Bulgarian Academy of Sciences(1) selected through
ISRO Announcement Of Opportunity (AO). Two of the ESA
instruments have Indian collaboration. |
|
| 8. What type of propulsion
system will Chandrayaan-1 use? How much propellant will
it carry? |
|
| Chandrayaan-1 will use bipropellant integrated propulsion
system. The propulsion system consists of a unified bi-propellant
system for orbit raising and attitude control. It consists
of one 440N engine and eight numbers of 22N thrusters,
mounted on the negative roll face of the spacecraft. Two
tanks each with a capacity of 390 liter are used for storing
fuel and oxidizer. |
|
| 9. How will mission controllers
communicate with the spacecraft? |
|
| If the spacecraft encounters a problem, it can establish
contact with controllers on Earth through the Deep Space
Network. |
|
| 10. Can the team fix the
spacecraft from Earth? |
|
| If a component on the spacecraft fails, controllers
on Earth can instruct Chandrayaan to bring a backup online.
If the spacecraft points in the wrong direction, its attitude
can be corrected. If the spacecraft deviates from the
desired trajectory, a controlled burn (thruster firing)
can be performed to put it back on track. |
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| Back
to Top |
| Most minor problems can be corrected from Earth with
existing onboard instruction systems. |
|
| 11. How is the spacecraft
powered? |
|
| The spacecraft is mainly powered by its solar array,
which includes one solar panel covering a total area of
2.15 X 1.8 square meters, generating 700W power. The panels
are made of materials rated to withstand extreme temperatures
~ 119 ºC to –165 ºC. The power produced by the solar
array is stored in a Lithium-ion battery, and then distributed
from the battery to the spacecraft subsystems. The power
system is designed to support various phases of the mission.
The power will supplement the mission with equal efficiency
in both noon/midnight and dawn/dusk orbits. The power
system consists of power generation, energy storage and
power conditioning elements. 36AH Li-Ion battery powers
the spacecraft during orbital and lunar eclipses. Power
electronics system controls the solar array power to supply
the load and charge the batteries. |
|
| 12. What other missions
are scheduled to study Moon? |
|
| The first leap in Lunar observation was made by Galileo
Galilei who used his new invention the telescope to observe
mountains and craters on the lunar surface. |
|
| The first man-made object to reach the Moon was the
unmanned Soviet probe Luna 2 in September 1959. Luna 9
was the first probe to soft land on the Moon in February
1966 and transmit pictures from the Lunar surface. The
first robotic lunar rover to land on the Moon was the
Soviet Lunokhod 1 in November 1970. |
|
| Humans first landed on the Moon on July 20, 1969. The
first man to walk on the lunar surface was Neil Armstrong,
commander of the American mission Apollo 11. The last
man to walk on the Moon was in December 1972 by Eugene
Cernan during Apollo 17 mission. |
|
| Moon samples have been brought back to Earth by three
Russian Luna missions (16, 20, and 24) and the US Apollo
missions 11, 12 and 14 through 17. |
|
| The European Space Agency has launched European spacecraft
Smart1 on September 27 2003 to explore the Moon, survey
the lunar environment and create an X-ray map of the Moon.
Japan has two planned lunar missions, LUNAR-A and Selene.
India plans to launch a lunar orbiter for simultanious
chemical and mineralogical study of the lunar surface.
The People’s Republic of China has also expressed
ambitious plans for exploring the Moon (Change series).
The Lunar Reconnaissance Orbiter (LRO) of USA is designed
to map the surface of the Moon and characterize future
landing sites in terms of terrain roughness, usable resources,
and radiation environment with the ultimate goal of facilitating
the return of humans to the Moon. |
|
| Back
to Top |
| 13. Comparison between earth
and moon |
|
| Basic parameters of the earth and the moon |
|
|
Parameters |
|
Moon
|
|
Earth |
|
Ratio |
|
|
|
|
|
|
|
| Mass
(1024 kg) |
|
0.07349 |
|
5.9736 |
|
0.0123
|
|
|
|
|
|
|
|
| Volume
(1010 km3) |
|
2.1958 |
|
108.321 |
|
0.0203 |
|
|
|
|
|
|
|
|
Equatorial radius(km) |
|
1738.1 |
|
6378.1 |
|
0.2725
|
|
|
|
|
|
|
|
|
Polar radius (km) |
|
1736.0 |
|
6356.8 |
|
0.2731
|
|
|
|
|
|
|
|
|
Volumetric mean radius (km) |
|
1737.1 |
|
6371.0 |
|
0.2727
|
|
|
|
|
|
|
|
|
Ellipticity |
|
0.0012 |
|
0.00335 |
|
0.36
|
|
|
|
|
|
|
|
|
Mean density (kg/m3) |
|
3350 |
|
5515 |
|
0.
607 |
|
|
|
|
|
|
|
|
Surface gravity (m/s2) |
|
1.62 |
|
9.78 |
|
0.166
|
|
|
|
|
|
|
|
|
Escape velocity (km/s) |
|
2.38 |
|
11.2 |
|
0.213 |
|
|
|
|
|
|
|
|
Obliquity |
|
6.7 |
|
23.4 |
|
0.286 |
|
|
|
|
|
|
|
|
Rotational period |
|
27.32 days |
|
23 hr 56 min 4.09s |
|
1.138 |
|
|
|
|
|
|
|
|
Revolution period |
|
23.32 days |
|
365.26 days |
|
0.0748 |
|
|
|
|
|
|
|
|
Eccentricity |
|
0.055 |
|
0.017 |
|
3.235 |
|
|
|
|
|
| Back
to Top |
| 14. Is there water-ice present
on the Moon? |
|
| The comets and meteorites continuously bombard the surface
of the Moon. Many of these objects contain water and as
a result of their impact may leave water molecules on
the lunar surface. Solar wind hydrogen bombarding the
lunar surface continuously may also lead to production
of water molecule through interaction with oxygen present
in the lunar soils. Due to solar heating much of this
water evaporate and lost into space very fast. However,
the current hypothesis is that some of the water molecules
may reach areas that are permanantly shadowed from sunlight
and gets trapped and significant traces of water/water
ice may be present in such regions of the Moon. |
|
| Due to the very slight "tilt" (only 1.5°)
of the Moon’s axis, some of the deep craters. particularly
near the polar regions never receive any light from the
Sun — they are permanently shadowed and can act
as permanent trap of water molecules and in such craters
scientists expect to find water in frozen form, if it
is there at all. |
|
| The Radar reflectivity experiments performed by Clementine
hinted at the possibility of existence of large amounts
of water frozen on these permanently shadowed regions
of the moon. |
|
| Lunar Prospector’s neutron spectrometer detected
bursts of slow neutrons over the moon’s poles, suggesting
presence of hydrogen atoms and hence possible presence
of water/ice. However, these experiments could not decisively
confirm the presence of water/ice on moon, which still
remains a mystery. |
|
| If there’s water ice present on the Moon then
we won't have to transport water from Earth to the Moon,
which would be extremely expensive. But instead will be
able to rely on lunar ice. This is important for a cost-effective
lunar habitation. |
|
| 15. What is the temperature
on the moon? |
|
| The moon undergoes extremes in temperature -- it is
scorching hot at 130 º C during the day and freezing cold
at –180 º C during night. |
|
| 16. Is there any Life on
moon? |
|
| So far none of the lunar missions have detected any
signature of presence of life on the Moon. |
|
| 17. Why do we see only one
side of the Moon? |
|
| As the Moon orbits, it always presents the same side
toward the Earth. This is so because Earth's gravity has
slowed the Moon’s rotation so that it just matches
the time it takes to go around the Earth. So the Moon
takes the same amount of time to revolve around the Earth
as it takes to rotate around its spin axis. |
|
| Back
to Top |
| 18. How was the Moon formed? |
|
| There are various theories on the evolution of Earth
and Moon system. Currently four main hypotheses have been
considered to explain the origin of the Moon:
1. Simultaneous
Formation: Earth and the Moon formed from the
solar nebula separately, but near each other. During
or immediately following its formation, the Moon began
to orbit Earth. This theory is able to explain why Earth
and Moon rocks are so similar but cannot explain the
fact why the lunar soil is depleted of Iron (Fe).
2. Capture:
Moon formed somewhere else in the Solar System where
the iron content was lower. After it formed, it drifted
and came near Earth and Earth’s gravitational
field captured the Moon. Eventually, the Moon settled
into its current orbit. This theory cannot explain why
Earth and Moon rocks are so similar except for the missing
ironand also the high angular momentum of the Earth-Moon
system.
3. Fission:
According to this hypothesis, originally there was no
Moon. Earth was spinning very rapidly (one day would
have been 2 hours long), and the spinning would have
been so rapid that a large chunk of Earth would have
split off, or fissioned, from the main body. This large
chunk would then cool and become the Moon. This hypothesis
can explain why Earth and Moon rocks are similar (they
were the same body at one point, and the low iron content
of Moon can be explained by postulating that the material
which formed the Moon came from parts of the Earth which
are iron-poor. But this theory is not able to support
the conservation of angular momentum. The Earth and
Moon are both spinning and the Moon is revolving around
Earth, so the Earth-Moon system has angular momentum.
The laws of physics say that angular momentum must be
conserved as things change. If Earth and Moon are put
together into a single body, and calculate the angular
momentum, it is found that Earth would spin about once
every 8 hours. However, for fission to explain the Moon’s
existence, Earth would have to spin four times that
quickly. This contradiction rules out the fission hypothesis. |
4.
Giant-Impact: This hypothesis suggests
that a body about 1-3 times the size of Mars slammed
into Earth at a time shortly after Earth’s
formation but after it has formed an iron core.
When the impact happened, it blasted a large part
of Earth into space and the ejecta then began
orbiting Earth. The material blasted off Earth
coalesced into the Moon. This hypothesis is able
to explain (a) the missing Moon iron as most of
the material blasted into space would have been
depleted in iron, (b) Moon rocks and Earth rocks
are so similar because they came from the same
place and (c) why the Moon’s orbit as well
as the Earth’s orbit are tilted.
The Giant Impact hypothesis is currently the favoured
explanation for the origin of Moon. |
|
 |
|
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| Back
to Top |
| 19. What is the total budget
for realising Chandrayaan-1 mission? |
|
| The budgetary estimate for realising the proposed Indian
lunar mission Chandrayaan-1 stands at Rs. 386.00 crores
(about $76 million). This includes Rs. 53.00 crores (about
$11 million) for Payload development, Rs. 83.00 crores
(about $17 million) for Spacecraft Bus, Rs. 100.00 crores
($20 million) towards establishment of Deep Space Network,
Rs. 100.00 crores ($20 million) for PSLV launch vehicle
and Rs. 50.00 crores ($10 million) for scientific data
centre, external network support and programme management
expenses. |
|
| 20. Chronology of Lunar Missions |
|
| No |
Launch
date |
Mission |
Country |
Accomplishment |
| 1. |
2 Jan 1959 |
Luna 1 |
USSR |
First lunar flyby,
magnetic field |
| 2. |
3 Mar 1959 |
Pioneer
4 |
USA |
Lunar flyby by 60,000
km, radiation |
| 3. |
12 Sept 1959 |
Luna 2
|
USSR |
First hard landing,
magnetic field |
| 4. |
4 Oct 1959 |
Luna 3
|
USSR |
First photos of lunar
farside |
| 5. |
23 Aug 1961 |
Ranger
1 |
USA |
Attempted test flight |
| 6. |
18 Nov 1961 |
Ranger
2 |
USA |
Attempted test flight |
| 7. |
26 Jan 1962 |
Ranger
3 |
USA |
Missed the Moon by
36,793 km |
| 8. |
23 Apr 1962 |
Ranger
4 |
USA |
Crashed on the lunar
farside |
| 9. |
18 Oct 1962 |
Ranger
5 |
USA |
Missed the Moon by
724 km |
| 10. |
2 Apr 1963 |
Luna 4
|
USSR |
Missed the Moon by
8,500 km |
| 11. |
30 Jan 1964 |
Ranger
6 |
USA |
Hard landing, television
failed |
| 12. |
29 July 1964 |
Ranger
7 |
USA |
Hard landing, First
close-up TV |
| 13. |
17 Feb 1965 |
Ranger
8 |
USA |
Hard landing, close-up
TV |
| 14. |
21 Mar 1965 |
Ranger
9 |
USA |
Hard landing, close-up
TV |
| 15. |
9 May 1965 |
Luna 5
|
USSR |
Crashed on the Moon |
| 16. |
8 June 1965 |
Luna 6
|
USSR |
Missed the Moon by
1,60,000 km |
| 17. |
18 July 1965 |
Zond 3
|
USSR |
Photographed lunar
farside |
| 18. |
4 Oct 1965 |
Luna 7
|
USSR |
Crashed on the Moon |
| 19. |
3 Dec 1965 |
Luna 8
|
USSR |
Crashed on the Moon |
| 20. |
31 Jan 1966 |
Luna 9
|
USSR |
First soft landing
and TV panorama |
| 21. |
31 Mar 1966 |
Luna 10
|
USSR |
First lunar satellite,
gamma-spectra, magnetic and gravity measurements |
| 22. |
30 May 1966 |
Surveyor
1 |
USA |
Lander, on-surface
T V, soil mechanics |
| 23. |
10 Aug 1966 |
Lunar Orb1
|
USA |
TV imaging, radiation,
micrometeorites |
| 24. |
24 Aug 1966 |
Luna 11
|
USSR |
Orbiter, gamma-and
X-ray measurements, gravity, micrometeorites |
| 25. |
22 Oct 1966 |
Luna 12
|
USSR |
Orbiter, TV imaging |
| 26. |
6 Nov 1966 |
Lunar Orb
2 |
USA |
TV imaging, radiation,
micrometeorites |
| 27. |
21 Dec 1966 |
Luna 13
|
USSR |
Lander, on-surface
T V, soil mechanics |
| 28. |
5 Feb 1967 |
Lunar Orb
3 |
USA |
TV imaging, radiation,
micrometeorites |
| 29. |
17 Apr 1967 |
Surveyor
3 |
USA |
Lander, on-surface
T V, soil mechanics |
| 30. |
4 May 1967 |
Lunar Orb
4 |
USA |
TV imaging, radiation,
micrometeorites |
| 31. |
19 July 1967 |
Explorer
35 |
USA |
Orbiter, Plasma, fields
and particles |
| 32. |
1 Aug 1967 |
Lunar Orb
5 |
USA |
TV imaging, radiation,
micrometeorites |
| 33. |
8 Sept 1967 |
Surveyor
5 |
USA |
Lander, on-surface
T V, First chemistry |
| 34. |
7 Nov 1967 |
Surveyor
6 |
USA |
Lander, on-surface
T V, chemistry |
| 35. |
7 Jan 1968 |
Surveyor
7 |
USA |
Lander, on-surface
T V, chemistry |
| 36. |
7 Apr 1968 |
Luna 14
|
USSR |
Orbiter, gamma-spectra.,
magnetic measurements |
| 37. |
14 Sept 1968 |
Zond 5
|
USSR |
First lunar flyby and
Earth return |
| 38. |
10 Nov 1968 |
Zond 6
|
USSR |
Lunar flyby and Earth
return |
| 39. |
21 Dec 1968 |
Apollo
8 |
USA |
First humans to orbit
the Moon |
| 40. |
18 May 1969 |
Apollo
10 |
USA |
First docking in lunar
orbit |
| 41. |
13 July 1969 |
Luna 15
|
USSR |
Failed robotic sampler |
| 42. |
16 July 1969 |
Apollo
11 |
USA |
First humans on the
Moon (20 July) |
| 43. |
6 Aug 1969 |
Zond 7
|
USSR |
Lunar flyby and Earth
return |
| 44. |
14 Nov 1969 |
Apollo
12 |
USA |
Human landing, Oceanus
Procellarum |
| 45. |
11 Apr 1970 |
Apollo
13 |
USA |
Aborted lunar landing |
| 46. |
12 Sept 1970 |
Luna 16
|
USSR |
First robotic sample
return, Mare Feccunditatis |
| 47. |
20 Oct 1970 |
Zond 8
|
USSR |
Lunar flyby and Earth
return |
| 48. |
10 Nov 1970 |
Luna 17
|
USSR |
First robotic rover
Lunokhod 1, Mare Imbrium |
| 49. |
31 Jan 1971 |
Apollo
14 |
USA |
Human landing, Fra
Mauro |
| 50. |
26 July 1971 |
Apollo
15 |
USA |
Human landing, Hadley-Apennine |
| 51. |
2 Sept 1971 |
Luna 18
|
USSR |
Failed robotic sampler |
| 52. |
28 Sept 1971 |
Luna 19
|
USSR |
Orbiter, lunar gravity,
T V, micrometeorites |
| 53. |
14 Feb 1972 |
Luna 20
|
USSR |
Robotic sample return,
Apollonius |
| 54. |
16 Apr 1972 |
Apollo
16 |
USA |
Human landing, Descartes |
| 55. |
7 Dec 1972 |
Apollo
17 |
USA |
Human landing, FIRST
geologist on the Moon, Taurus-Littrow |
| 56. |
8 Jan 1973 |
Luna 21
|
USSR |
Robotic rover Lunokhod
2, Le Monier |
| 57. |
10 Jun 1973 |
Explorer
49 |
USA |
Non-lunar radio astronomy
from lunar orbit |
| 58. |
29 May 1974 |
Luna 22
|
USSR |
Orbiter, lunar gravity,
T V, micrometeorites |
| 59. |
28 Oct 1974 |
Luna 23
|
USSR |
Failed robotic sampler |
| 60. |
9 Aug 1976 |
Luna 24
|
USSR |
Robotic sampler return,
Mare Crisium |
| 61. |
24 Jan 1990 |
Hiten |
Japan |
Flyby and orbiter,
technological experiments |
| 62. |
25 Jan 1994 |
Clementine |
USA |
Orbiter, imaging lunar
surface in U V, VIS, IR, laser altimetry |
| 63. |
6 Jan
1998 |
Lunar Prospector |
USA |
Gamma-neutron-alpha
spectrometry, magnetometry, gravity |
| 64. |
Sept 2003 |
SMART-1 |
ESA |
Solar electric propulsion,
near IR and X-ray Spectrometer |
| 65. |
2007 |
Lunar-A |
Japan |
Seismic heat flow phenomena |
| 66. |
2007 |
Selene |
Japan |
Mapping of lunar topography,
surface composition & magnetic field |
| 67. |
2007 |
Chang-e |
China |
Explore lunar surface
environment,,, topography, geological structures. |
| 68. |
2008 |
Chandrayaan-1 |
India |
High resolution Chemical,
mineralogical and photo-geological mapping of lunar
surface in visible, near IR, low and high energy
X-rays. |
| 69. |
2008 |
Lunar Reconnaissance
Orbiter |
USA |
Obtain
data to facilitate returning men safely to the moon |
|
|
|
Note: If you have a question
that has not been answered here, we invite you to
submit it to us. We also welcome questions and comments
on the CHANDRAYAAN-1 Website. Send a note to moon@isro.gov.in |
|
|
|
