Chandrayaan-2

Chandrayaan-2/Čandraján-2

je druhá mesačná prieskumná misia Indie po Čandraján-1.[1] Vyvinutá indickou organizáciou pre výskum vesmíru (ISRO). Misia použije nosič Geosynchronous Satellite Launch Vehicle Mark III (GSLV Mk III).[2] Obsahuje lunárny orbiter, lander a rover, všetko vyvinuté Indiou.[3]

Termín štartu je 14. 7. 2019 v 21:21 UTC a pozemná sonda s vozítkom sa pokúsi o mäkké pristátie 6. 9. medzi dvoma kráterami Manzinus C a Simpelius N na južnej mesačnej šírke asi 70 °. Ak bude úspešná bude druhou misiou s pristátím rovera v blízkosti lunárneho južného pólu. [5]
Landing site[21]Coordinates
SLS54 (prime site)70.90267°S 22.78110°E
ALS01 (alternate site)67.87406°S 18.46947°W
https://www.hou.usra.edu/meetings/lpsc2018/pdf/1975.pdf

Podľa ISRO táto misia použije a otestuje rôzne nové technológie a uskutoční nové experimenty. Kolesový rover sa bude pohybovať na povrchu Mesiaca a bude vykonávať chemické analýzy. Údaje budú odovzdávané na Zemi cez modul Čandraján-2 na orbite.

Launch configuration. At 3850 kg
Lander
Orbiter
Rover

Sonda bude vynesená na parkovaciu dráhu 170 - 40 400 km okolo Zeme. Na eliptické obežnej dráhe okolo Zeme strávi sonda asi 16 dní a vykoná 5 zážihov motorov, ktorými bude postupne zvyšovať apogeum dráhy tak, až mierne presiahne dráhu Mesiaca. Prelet k Mesiacu bude trvať asi 5 dní. Po dosiahnutí sféry gravitačného vplyvu Mesiaca, vlastným pohonom spomalí tak, aby bola zachytená Mesiacom a dostala sa na jeho obežnú dráhu, čo sa stane 4. alebo 5. augusta. Eliptickú dráhu okolo Mesiaca bude postupne upravovať na výslednú kruhovú dráhu vo výške 100 km nad povrchom Mesiaca. Celkovo na obežnej dráhe Mesiaca strávi 33 dní.



Chandrayaan-2 is scheduled to launch 2019-July-14 @ 21:21 UTC from Satish Dhawan Space Centre on Sriharikota Island, India. Launch vehicle is a GSLV-MK3.

It consists of an orbiter, a lander ("Vikram") and a rover ("Pragyan")

After launch into Earth parking orbit (170 x 40400 km altitude), a series of maneuvers will rogressively raise the apogee of the spacecraft until a subsequent trans-lunar injection burn.

It will be inserted into an initial elliptic lunar orbit on Aug 5 or 6.

After lunar obit insertion, the lander and orbiter separate. The orbiter will then be placed in a 100 km circular polar orbit with a series of engine burns. Subsequently, the lander will separate and touch down at the predetermined site close to the lunar south pole.

Touchdown is to occur 2019-Sep-6 on a high plain between two craters, Manzinus C and Simpelius N, about 70 degrees south of the equator.

The orbiter mission covers 1 year, in a 100-km circular polar orbit.

The six-wheeled Pragyan rover, whose name means "wisdom" in Sanskrit, will be deployed from a ramp after landing. It is solar-powered and capable of  traveling up to 500 meters on the lunar surface at a speed of 1 cm/s.

The lander/rover missions are planned for 14-15 days (1 lunar daylight interval).

SPACECRAFT DETAILS
Launch mass : 3850 kg
Lunar orbital mass: 2379 kg (solar arrays ~1000 W
Lunar lander mass: 1471 kg (solar arrays ~ 650 W)
Rover mass : 27 kg (solar arrays ~ 50 W)

TRAJECTORY:
This is a pre-launch planning trajectory created 2019-July-3. It begins in the elliptical Earth parking orbit, 19 minutes after launch:


orbit Perigeum date Apogeum date
1 182 2019-Jul-14 21:39:18 38815 2019-Jul-15 14:54:00 1.
2 171 2019-Jul-15 20:39:00 42335 2019-Jul-16 03:00:00 2.
3 171 2019-Jul-16 09:21:00 42333 2019-Jul-16 15:42:00
4 205 2019-Jul-17 10:45:00 42333 2019-Jul-17 17:06:00
5 209 2019-Jul-17 23:28:00 55535 2019-Jul-18 08:12:00 3.
6 215 2019-Jul-18 16:59:00 55537 2019-Jul-19 01:45:00
7 210 2019-Jul-19 10:31:00 55538 2019-Jul-19 19:15:00
8 210 2019-Jul-20 04:02:00 55539 2019-Jul-20 12:46:00
9 209 2019-Jul-20 21:34:00 71380 2019-Jul-21 09:30:00 4.
10 210 2019-Jul-21 21:31:00 71382 2019-Jul-22 09:26:00
11 205 2019-Jul-22 21:27:00 71383 2019-Jul-23 09:23:00
12 207 2019-Jul-23 21:24:00 97550 2019-Jul-24 15:21:00 5.
13 387 2019-Jul-25 09:22:00 97541 2019-Jul-26 03:16:00
14 216 2019-Jul-26 21:13:00 139115 2019-Jul-28 02:12:00 6.
15 242 2019-Jul-29 07:12:00 139075 2019-Jul-30 12:10:00
16 241 2019-Jul-31 17:08:00 359979 2019-Aug-05 02:59:00 Moon


CHANDRAYAAN-2 LANDING TRAJECTORY
From M. Annadurai et al. presentation to the 10th IAA Symposium on the Future of Space Exploration, Torino, Italy, 27-29 June, 2017.


Chandrayaan-2 Lunar Lander (with Rover) Soft Landing Sequence (image credit: ISRO)



The lander's propulsion system consists of eight 50 N (11 lbf) thrusters for attitude control and five 800 N (180 lbf) liquid main engines derived from ISRO's 440 N (99 lbf) Liquid Apogee Motor.[37][47] Initially, the lander design employed four main liquid engines, but a centrally mounted engine was added to handle new requirements of having to orbit the Moon before landing. The additional engine is expected to mitigate upward draft of lunar dust during the soft landing.[48]

Payload
ISRO selected five scientific instruments for the orbiter, four for the lander,[56] and two for the rover.[26][57] While it was initially reported that NASA and ESA would participate in the mission by providing some scientific instruments for the orbiter,[58] ISRO in 2010 had clarified that due to weight restrictions it will not be carrying foreign payloads on this mission.[59]However, in a last moment update just a month before the launch of the mission, a small laser retroreflector from NASA was added to the lander's payload to help scientists measure exact distances to the Moon.[60]Orbiter payload
Large Area Soft X-ray Spectrometer (LASS) from ISRO Satellite Centre (ISAC), Bangalore and Solar X-ray monitor (XSM) from Physical Research Laboratory (PRL), Ahmedabad for mapping major elements present on the lunar surface.[26]
L and S band Synthetic Aperture Radar (SAR) from Space Applications Centre (SAC), Ahmedabad for probing the first few tens of metres of the lunar surface for the presence of different constituents, including water ice. SAR is expected to provide further evidence confirming the presence of water ice below the shadowed regions of the Moon.[26]
Imaging IR Spectrometer (IIRS) from SAC, Ahmedabad for mapping of lunar surface over a wide wavelength range for the study of minerals, water molecules and hydroxyl present.[26]
Neutral Mass Spectrometer (ChACE-2) from Space Physics Laboratory (SPL), Thiruvananthapuram to carry out a detailed study of the lunar exosphere.[26]
Terrain Mapping Camera-2 (TMC-2) from SAC, Ahmedabad for preparing a three-dimensional map essential for studying the lunar mineralogy and geology.[26]Vikram lander payload
Seismometer for studying Moon-quakes near the landing site[56][8][61]
Thermal probe for estimating the thermal properties of the lunar surface[8]
Langmuir probe for measuring the density and variation of lunar surface plasma[56][8]
Radio occultation experiment for measuring the total electron content[8]
A laser retroreflector array (LRA) by NASA Goddard Space Flight Center for precise measurements of the Earth–Moon distance.[60]Pragyan rover payload
Laser induced Breakdown Spectroscope (LIBS) from Laboratory for Electro Optic Systems (LEOS), Bangalore.[26]
Alpha Particle Induced X-ray Spectroscope (APIXS) from PRL, Ahmedabad.




The mission is planned to fly on a Geosynchronous Satellite Launch Vehicle Mark III (GSLV Mk III) with an approximate lift-off mass of 3,877 kg (8,547 lb) from Satish Dhawan Space Centre on Sriharikota Island.[8][7][37] As of June 2019, the mission has an allocated cost of ₹978 crore(approximately US$141 million) which includes ₹603 crore for space segment and ₹375 crore as launch costs on GSLV Mk III.[17][38] Chandrayaan-2 stack would be initially put in a Earth parking orbit of 170 km perigee and 40,400 km apogee by the launch vehicle.[39] It will then perform orbit raising operations followed by trans-lunar injection using its own power.
Orbiter[edit]

The orbiter will orbit the Moon at an altitude of 100 km (62 mi).[40] The mission will carry five instruments on the orbiter. Three of them are new, while two others are improved versions of those flown on Chandrayaan-1. The approximate launch mass will be 2,379 kg (5,245 lb).[2][3][26][41] The Orbiter High Resolution Camera (OHRC) will conduct high-resolution observations of the landing site prior to separation of the lander from the orbiter.[40][1] Interfaces between the orbiter and its GSLV Mk III launch vehicle have been finalised.[42] The orbiter's structure was manufactured by Hindustan Aeronautics Limited and delivered to ISRO Satellite Centre on 22 June 2015.[42][43]

The mission's lander is called Vikram (Sanskrit: विक्रम, lit. 'Valour')[45] named after Vikram Sarabhai (1919-1971) who is widely regarded as the father of the Indian space programme.[46]

The Vikram lander will detach from the orbiter and descend to a lunar orbit of 30 km × 100 km (19 mi × 62 mi) using its 800 N (180 lbf) liquid main engines. It will then perform a comprehensive check of all its on-board systems before attempting to land on the lunar surface. Unlike Chandrayaan-1's Moon Impact Probe, the Vikram lander will make a soft landing, deploy the rover, and perform some scientific activities for approximately 15 days. The approximate combined mass of the lander and rover is 1,471 kg (3,243 lb).[2][3] The preliminary configuration study of the lander was completed in 2013 by the Space Applications Centre (SAC) in Ahmedabad.[27]

The lander's propulsion system consists of eight 50 N (11 lbf) thrusters for attitude control and five 800 N (180 lbf) liquid main engines derived from ISRO's 440 N (99 lbf) Liquid Apogee Motor.[37][47] Initially, the lander design employed four main liquid engines, but a centrally mounted engine was added to handle new requirements of having to orbit the Moon before landing. The additional engine is expected to mitigate upward draft of lunar dust during the soft landing.[48]

Some associated technologies include a high resolution camera, navigation camera, hazard avoidance camera, an 800 N throttleable liquid main engine and attitude thrusters, altimeter, velocity meter, accelerometer, and the software needed to run these components.[1][40] The lander's main engine has successfully undergone a high altitude test for a duration of 513 seconds, and closed loop verification tests of the sensors, actuators and software were completed in 2016.[42] Engineering models of the lander began undergoing ground and aerial tests in late October 2016, in Challakere in the Chitradurgadistrict of Karnataka. ISRO created roughly 10 craters on the surface to help assess the ability of the lander's sensors to select a landing site.[49]
Pragyan rover[edit]


The mission's rover is called Pragyan (Sanskrit: प्रज्ञान, lit. 'Wisdom').[50][51] The rover's mass is about 27 kg (60 lb) and will operate on solar power.[2][3] The rover will move on 6 wheels traversing 500 meter distance on the lunar surface at the rate of 1 cm per second,[52][53] performing on-site chemical analysis and sending the data to the lander, which will relay it to the Earth station.[26][41][17]
Stereoscopic camera-based 3D vision using two NAVCAMs in front of rover will provide the ground team controlling the rovers a 3D view of the surrounding terrain, and help in path-planning by generating a digital elevation model of the terrain.[54]
Control and motor dynamics - The rover has a rocker-bogie suspension system and six wheels, each driven by independent brushless DC electric motors. Steering is accomplished by differential speed of the wheels or Skid Steering.[55]


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