Chandrayaan 3 and common navigation method in spacecrafts

Spacecraft navigation without GPS.

 Comparison table:

Examples:

Astrix 90 fibre optic gyroscope FOG used on ExoMars

Hazard avoidance in ALHAT in project Morpheus lander

SPLICE 

NDL Navigational Doppler Lidar to be used on Intuitive Machines IM-1, as early as Nov 15 2023, launched by Spacex falcon 9

 

Chandrayaan-3 landing:

Laser Inertial Referencing and Accelerometer Package (LIRAP): LIRAP is like a special “balance and motion sensor” for the lander. It helps the lander understand its position, orientation, and any movements it makes during its descent and landing on the lunar surface. ( Laser gyroscope)

Chandrayaan-2 had a front-facing camera(TMC-2). Still, the communication system could not transfer the images in real-time. But now the communication system has been beefed up to enable the front-facing camera of the CY3 lander to transmit the images in real-time to the ISRO control centre. The images are collected as part of the autonomous hazard identification and avoidance manoeuvre. “The images from the front-facing camera will be used for autonomous navigation and hazard avoidance manoeuvre, and the images will be sent back to the ground in real-time,” says Annadurai. “Last time, only housekeeping telemetry was downlinked in real-time,” he added. 

Hi res DEM was generated when Chandrayaan 2 orbiting at 100 Km , GSD 0.25m, swath of 3km

    Ka-Band Altimeter (KaRA): KaRA is like a high-tech “height measurement tool” for the lander. It uses radio waves to measure the distance between the lander and the Moon’s surface, helping it know how far it is from the ground.(40-100m)

    Lander Position Detection Camera (LPDC) (Landing Imager?): LPDC is like a “smart camera” that helps the lander see where it is on the Moon’s surface. It takes pictures and helps the lander identify its exact position and location.

    LHDAC (Lander Hazard Detection & Avoidance Camera): LHDAC is like a “safety camera” for the lander. It scans the lunar surface for any obstacles or hazards that could be dangerous during landing. This helps the lander avoid any potential dangers and land safely.( terminal descent phase, similar to ALHAT, up to 2500m range )

    Laser Altimeter (LASA): LASA is like a “precision height measurer” for the lander. It uses laser beams to measure the distance between the lander and the Moon’s surface very accurately, helping it maintain a safe and precise descent.( before terminal descent, 1.6-3km)

    Laser Doppler Velocimeter (LDV): LDV is like a “speedometer” for the lander. It uses laser light to measure the speed of the lander during its descent and landing, ensuring a controlled and safe landing.(before terminal descent)

    Lander Horizontal Velocity Camera (LHVC) TMC-2?: LHVC is like a “side view camera” for the lander. It helps the lander see its horizontal speed and movement as it approaches the lunar surface, ensuring a smooth landing.( Start imaging 4400km above moon)

    Micro Star Sensor: The Micro Star Sensor is like a “celestial compass” for the lander. It helps the lander determine its orientation and alignment with respect to the stars, which is crucial for precise navigation.( during navigation)

    Inclinometer & Touchdown Sensors: These sensors are like “tilt detectors” and “landing detectors” for the lander. The inclinometer measures the angle at which the lander is tilted during its descent, and the touchdown sensors detect when the lander touches down on the lunar surface.

Landing Imager

ISRO’s Chandrayaan-3 lander-rover-based mission is proposed to land in the plateau between two craters Manzinus and Boguslawsky and a third Simpelious in an area between 68 and 70° S and 31 and 33° E coordinates near the moon’s south pole. targetting 69.37˚S 32.35˚E

Additionally, an alternate landing site has also been proposed in the west of Moretus crater (∼114 km diameter; coordinates: 70.6° S, 6.2° W), within an area between 68 and 70° S and 16 and 18° W.

ISRO Chairman S. Somnath unveiled the ensemble of sensors guiding this cosmic venture. Velocimeters and altimeters contribute vital speed and altitude data, forming the backbone of AI’s navigation prowess. The array of cameras, from hazard avoidance to inertia-based, paints a visual canvas of the lunar terrain. These diverse inputs merge seamlessly through complex algorithms, crafting a holistic image of the lander’s whereabouts.

Cf mars helicopter ingenuity 

Landing schedule( in AET):

Propulsion module separation:17/8 (~ 2 days earler than CH2)

Then de-orbit/de-boost to 100 km x 30 km orbit

Dss34 22/8 1215 1400

Dss36 23/8 1110-2250

Dss34 23/8 1815-2300

cdscc

ESA EStrack

landing success:

23/8/2023 12:34 UTC, 

-69.37302, 32.32017  (in a 10x10m box) twitter

Region of -230 deg C

Aug 2023

Failed to wake up after hibernation 

Reference:

Terrain relative navigation 

Ixblue

Drpress 

integration of vision and navigation information 

Gareeb

Federal, 10 key upgrades 

Chandrayaan 2, youtube 

Role of AI technology 

Twitter