India's Moon Exploration Program

[Indx TechStyle]

Current Space Situation around the Moon – An assessment

Introduction

Exploration of space beyond the near-Earth regime has been one of the most challenging and fascinating ventures of humankind and continues to capture the imagination of generations. Over the ages, several space-faring nations have undertaken numerous missions to explore most of the planets in the solar system, their natural moons, various minor planets/ asteroids, comets and even interplanetary voyages. The Moon and Mars are the most explored and also comparatively more crowded planetary bodies at present. India’s Chandryaan-3 (CH3) is the latest entry into the lunar orbit. More intensified activities around the Moon are foreseen in the next few years due to the renewed interest in lunar exploration, heralded by Artemis missions for return to the Moon and preparations for colonisation of Mars. While the previous missions were essentially aimed at scientific explorations, upcoming ventures will likely involve multiple actors of diverse interests, including those primarily driven by resource utilisation for commercial purposes. A better understanding of theenvironment is needed to formulate reasonable mitigation practices to avoid close-approach threats in planetary orbits.

The current Space Debris Mitigation Guidelines by the UN and Inter-Agency Space Debris Coordination Committee (IADC) are applicable to spacecraft and orbital stages “that will be injected into Earth orbit.Currently space debris pose a major threat to the long-term sustainability of outer space activities in the ever-increasingly congested Earth orbits. Therefore, based on the lessons learnt while operating in the near-Earth regime, it is interesting and desirable to undertake studies related to close approaches in view of the increasing number of objects in the lunar orbits.

Tracking of deep space objects

Observation and tracking of deep space objects are inherently more complex compared to that in the near-Earth regime, mainly due to the vast distance involved between the object and the observer which introduces considerable latency, signal attenuation and associated complexities. Functional assets like spacecraft/landers/rovers are tracked by active and passive means. Typical active techniques involve range and Doppler measurement, very long baseline interferometry (VLBI)/Delta Differential One-way Ranging (DOR), and laser ranging with retro-reflectors. Optical transponders have also been demonstrated for missions like the Messenger, Mars Global Surveyor, and Hyabusa-2 which can give better accuracy.

Lunar orbits

Orbital evolution in lunar orbit is primarily influenced by lunar gravity, gravity of the Sun and the Earth, and the Sun Radiation Pressure. For orbits lower than 500 km, non-uniformity of lunar gravity due to mass concentrations dominates, which along with the third body perturbations due to the Earth and the Sun causes the orbit eccentricity (without any change in the semi-major axis) to increase. As a result, the perilune altitude is gradually lowered leading to eventual impact with the lunar surface. For example, the expected orbital lifetime of a spacecraft at a 100 km circular orbit is about 160 days.

The major types of lunar orbitsinclude Halo orbit around Langrange’s point, Nearly Rectilinear Halo Orbit (NRHO), Low Lunar Orbit (LLO), and Distant Retrograde Orbit (DRO). NRHO orbits offer the advantages of being stable and requiring less orbit maintenance, maintaining continuous communication with Earth and other lunar orbiting crafts, eclipse avoidance etc. and are highly suitable to host lunar gateways. Several forthcoming missions may also be placed in similar orbits, but given the vast spatial extent of such orbits (far larger than the GEO belt), no congestion is anticipated in the foreseeable future. Majorityof the currentlyorbiting lunar probes operate in LLO.

The current situation around the moon

As of July 2023, there are 6 active lunar orbiters (see Fig-1). Two of the five probes of NASA’s THEMIS mission have been re-purposed under ARTEMIS (Acceleration, Reconnection, Turbulence and Electrodynamics of the Moon's Interaction with the Sun) as ARTEMIS P1 and ARTEMIS P2, both operate in eccentric orbits of low inclination. NASA’s Lunar Reconnaissance Orbiter (LRO) orbits the Moon in a nearly polar, slightly elliptical orbit. Chandrayaan-2, the second lunar mission of ISRO and Korea Pathfinder Lunar Orbiter (KPLO) also operate in polar orbits of 100 km altitude. NASA’s Capstone operates in a 9:2 resonant southern L2 NRHO, its perilune passes over the lunar North pole at 1500-1600 km altitude, while the apolune is over the South pole at a distance of nearly 70,000 km. The Japanese spacecraft Ouna which was placed in lunar orbit as part of Kaguya/SELENE mission in 2009 and Chandrayaan-1 launched in 2008 are the two defunct spacecraft. All the other orbiters have been either moved out of the moon-bound orbital regime or have landed/impacted the lunar surface, either deliberately or due to failure to land softly. For example, Chang’e 4 mission’s data relay satellite Queqiao, launched by China in May 2018, was later moved to a halo orbit near the Earth-Moon L2 point. Currently, the only operating rover is China’s Yutu-2 rover released by Chang’e 4, which operates on the far side. From the available media sources, it is expected that Luna-25 of Russia with a Lander and Rover will be in Lunar orbit of 100 km by August 16, 2023 and will be landing on South pole of the moon by August 21-23, 2023.

Lunar orbiting spacecraft

Table 1: Future Missions to Moon

Name	Country/ Organisation	Launch	Type
Luna-25	Russia	2023	Lander
Commercial Lunar Payload Services (CLPS)	USA	2023	Lunar delivery services
Lunar Trailblazer	USA	2023	Orbiter
Beresheet 2	Israel	2024	Orbiter and lander
VIPER (Volatiles Investigating Polar Exploration Rover)	USA	2024	Rover
Artemis II	USA	2025	Lander
China's Lunar Exploration Programme (CLEP): Chang’e 6,7,8	China	2024-2027	Lunar robotic research station
China’s lunar communication and navigation satellite constellation	China	2023	Relay satellites to support lunar surface operations
Hakuto-II and III	Japan	2024-2025	Orbiter/lander
SLIM (Smart Lander for Investigating Moon)	Japan	2023	Orbiter/lander
LUPEX (Lunar Polar Exploration Mission)	India/Japan	After 2024	Orbiter, lander, rover

Risk of Close Approaches in Lunar Orbits and its Mitigation

Even with a handful of orbiting spacecraft, frequent conjunctions are experienced by LRO, KPLO, and CH2O as their orbital regimes in LLO overlap. Sometimes such conjunctions even warrant collision avoidance manoeuvres to be executed to be on the safer side because of the uncertainty associated with orbital estimates. Till July 2023, Chandrayan-2 has performed 3 collision avoidance manoeuvres to mitigate critical close approaches with LRO and KPLO. It is noteworthy that effective coordination is taking place among the agencies to avoid critical conjunctions in the Lunar orbit. For Chandryaan-3 (CH3) mission, the propulsion module is expected to orbit around the moon in a circular LLO of about 150 km altitude for many years to come. Majority of the lunar landers are also likely to temporarily reside in LLO (typically for a few days or weeks) before landing.

Under the ambit of ISRO System for Safe and Sustainable Space Operations Management (IS4OM) critical analyses of each of the Lunar Bound Manoeuvres for orbit loweringare being performed to assess potential risks of close approaches with the other lunar orbiters before executing the manoeuvres.

Role of India and way forward

The space object population has been growing for space beyond the Earth as well as in the lunar environment, where the greater uncertainty associated with the orbital knowledge entailscollision risk assessment to be a necessity for safe operations for a spacecraft orbiting the Moon.

India has pro-actively taken up many initiatives in collaboration with International Organisations like Inter Agency Space Debris Coordination Committee (IADC), which include studies related to future evolution of space object environment in cislunar and lunar region to bring out specific guidelines and best practices for space operations to be sustainable in these regions.

 

[Cheran]

Somebody upset

China is just a template. Tomorrow it could will be us.

Ofc, if amerishits were to "win" the "new space race", they will only be "democratizing the lunar south pole".

 

[Sanglamorre]

View attachment 217814

Somebody upset

China is just a template. Tomorrow it could will be us.

Ofc, if amerishits were to "win" the "new space race", they will only be "democratizing the lunar south pole".

Which is why I'm happy we're taking part in the new era colonization. Actually having been there and being part of this race will ensure we get a chunk of this moon pie.

 

[Vamsi]

There have been so many failed rocket tests in Japan recently,



These are not very advanced rockets


This is reinventing the wheel

its not reinventing the wheel, just because one country achieved something, doesn't mean all countries will also have the same capability, hence each country should develop their own capabilities. India landing on moon might not add new to science, but it will give us independent capability

 

[Vamsi]

AS PER MY CALCULATIONS

Both are landing on ~ 69.5°S
Moon's 69.5°S latitude has circumference of ~ 3800 km / 360 Longitudes. = 10.6 km

Russia 43.5°E .
India 32.5°E

DISTANCE BETWEEN BOTH
11 * 10.6 = 117 KM

@Indx TechStyle
@Vamsi

What's the endurance of our rover.

Edit-
Just found out maximum distance travelled is 11km by USSR rover.
So it's impossible we could meet Luna25 110km far, that too at south pole.

max range for our rover is 500 meters

 

[Vamsi]

Luna has a ROver in it?

No, but as per the original plan of 2007, this lander was supposed to carry Pragyan rover as part of Chandrayaan-2

 

[AnantS]

Russia launches a Moon mission after 47 years, Luna-25 by Roscosmos might reach before ISRO's Chandrayaan-3

Indian space organisation ISRO, whose Chandrayaan 3 mission is also on the way to the Moon, has congratulated Roscosmos, the Russian space agency. | OpIndia News

www.opindia.com

 

[astransastra]

It is said Lander of Luna 25 is expected to function for one year where as C-3 rover is supposed to last only 14 earth days. How is Russia able to extend the lander life to 1 year on South pole of moon which is in shadows and hence no solar energy?

 

[AnantS]

It is said Lander of Luna 25 is expected to function for one year where as C-3 rover is supposed to last only 14 earth days. How is Russia able to extend the lander life to 1 year on South pole of moon which is in shadows and hence no solar energy?

Luna 25 has radio-isotope power generator, RITEG.

ISRO & BARC are also developing same for future missions. Dont go by title as RITEG/RTG are not used for direct propulsion. They are long term power source used over Li Ion batteries.

ISRO, BARC join hands to develop nuclear engines for rockets

ISRO and BARC are developing nuclear-powered engine, RTGs, to power satellites on deep space missions. RTGs use radioactive materials to generate heat, which is then converted to electricity to charge batteries and provide motive force. 5W RTG is the target. US spacecrafts have used RTGs in the...

www.thehindubusinessline.com

 

[SKC]

It is said Lander of Luna 25 is expected to function for one year where as C-3 rover is supposed to last only 14 earth days. How is Russia able to extend the lander life to 1 year on South pole of moon which is in shadows and hence no solar energy?

Did you forget that Russia was part of USSR which did all these things much earlier?

 

[ym888]

its not reinventing the wheel, just because one country achieved something, doesn't mean all countries will also have the same capability, hence each country should develop their own capabilities. India landing on moon might not add new to science, but it will give us independent capability

You actually agree with me



Other countries are inventing the wheel on their own

 

[TopWatcher]

Why are we worried so much about russia moon landing before india, anyhow they are previous USSR and already reached moon.

Here our first priority must be to show soft land capability to the world. The budget we use are very less compare to world space agencies.

ISRO has its own path. Moon bahut bada hai , kahin na kahin jagah mil hi jayengi.

 

[SKC]

Why are we worried so much about russia moon landing before india, anyhow they are previous USSR and already reached moon.

Here our first priority must be to show soft land capability to the world. The budget we use are very less compare to world space agencies.

ISRO has its own path. Moon bahut bada hai , kahin na kahin jagah mil hi jayengi.

Kis kis ko samjhaoge!

 

[astransastra]

Did you forget that Russia was part of USSR which did all these things much earlier?

Never mind i got the answer from poster 'Anants' above. I know USSR did several moon mission, but this specific case is related to Moon's south pole which doesn't have sun light, so wondered what Russia did that India didn't do.

 

[TopWatcher]

Kis kis ko samjhaoge!

Hmmm Sahi Kaha

 

[Rassil Krishnan]

max range for our rover is 500 meters

why, do you want to meet and dine with the russian rover ?

 

[Rassil Krishnan]

It is said Lander of Luna 25 is expected to function for one year where as C-3 rover is supposed to last only 14 earth days. How is Russia able to extend the lander life to 1 year on South pole of moon which is in shadows and hence no solar energy?

maybe they a radioactive matter engine that allows powering of the rover for a long time?i don't know.

we are also trying to develop our own i think

 

[Vamsi]

why, do you want to meet and dine with the russian rover ?

not me, but others

 

[RedHood108]

Why are we worried so much about russia moon landing before india, anyhow they are previous USSR and already reached moon.

Here our first priority must be to show soft land capability to the world. The budget we use are very less compare to world space agencies.

ISRO has its own path. Moon bahut bada hai , kahin na kahin jagah mil hi jayengi.

Honestly wasn't even bothered about the Russian Mission. Felt like a coincidence.

But then read the interview of the Roscosmos Chief. And seems like they were deliberately trying to land Luna-25 before Chandrayaan-3 just to snatch a stupid title.

Thats a fuckin cheap stunt. It wouldn't even serve any purpose other than quench their ego.

 

[Sanglamorre]

Honestly wasn't even bothered about the Russian Mission. Felt like a coincidence.

But then read the interview of the Roscosmos Chief. And seems like they were deliberately trying to land Luna-25 before Chandrayaan-3 just to snatch a stupid title.

Thats a fuckin cheap stunt. It wouldn't even serve any purpose other than quench their ego.

It's fine. USSR might have done it before but if they are looking to beat India, it must involve rejig of schedules at last minute. It might not be as successful if they're pressed for time.