Bevel Gears India's Role in the Chandrayaan-3 Moon Landing Mission

On August 23, 2023 at 12:32 UTC, India’s Chandrayaan-3 mission made a successful landing on the southern part of the moon near the crater Manzinus. After carrying out all of the Indian Space Research Organization (ISRO)–planned investigations and explorations on the lunar surface and before the start of the two-week lunar night, the Pragyan rover was put into sleep mode on September 2nd, 2023, and the Vikram lander on September 4th. We were able to catch up with Mushtaq Jamal, vice president of engineering and business development at Bevel Gears India Pvt Ltd (BGI), to discuss BGI's role in this monumental achievement for India. [Special thanks are due to Divya Sudarsanan, Content Editor for Gear Technology India, for helping facilitate this interview.]

For context, BGI was founded by Sulaiman Jamal in 1976, and, as the company name suggests, they specialize in manufacturing high-precision bevel gears. Across a very broad range from 5 mm to 1,800 mm, BGI covers various applications that you would not normally see produced at one facility such as robotics, automation, aerospace, high-speed machine tools, performance motorsport, aggregate, steel, mining, and space programs. The company's unique selling proposition (USP) is high mix, low volume, allowing for a large variety of customers across different international geographies.  

In terms of capabilities, BGI is the first private company in India to install multiple CNC bevel grinding machines, including both Klingelnberg and Gleason bevel grinders. BGI is presently the first and only company in India to have CNC straight bevel grinding. Another niche is Curvic coupling grinding. This was a result of the leadership team focusing on investing in bevel gear technology to stay relevant on a global level. 

Aaron Fagan: How did BGI come to be involved in India's moon-landing project and how long a process has this been? 

Mushtaq Jamal: BGI has been honing its capabilities and investing in new bevel technology for several years. Presently these technological upgrades include cutting-edge Gleason and Klingelnberg CNC spiral bevel grinding machines, CNC bevel gear cutting, and CNC inspection. These technological advancements are continually conveyed to both new and potential customers and this was shared at various vendor meetings with the government organizations. Once ISRO was made aware of our capabilities, they contacted us, and it took 12 months for our company to be approved and thereafter over two years to supply prototypes and the final products.

AF: Can you share aspects of the technical specifications of the gears in the project (i.e., material, design standards, production methods)?

MJ: As with most programs of this nature, details are shared selectively. As you would imagine with anything space-related, the requirement was the parts had to be low in weight with a specific emphasis on precision and accuracy. Thus, in the manufacturing process, we were chasing microns (one micron is a thousandth of a millimeter) and not production cycle time as you would in high-volume manufacturing. These particular bevel gears play a critical role in the Pragyan rover’s drivetrain and had to be fail-safe. Special steel grades were used, and the bevel gears had many critical processes along every step of the way. Demanding topography requirements had to be maintained too.

A big part of the reason for our selection in this project was our ability to not only manufacture but to measure very small bevel gears. We had installed a brand-new state-of-the-art CNC Gleason 475 GMS measuring center and this piece of equipment certainly gave the customer peace of mind. Today we make and measure some of the smaller bevel gears in the country going down to 0.4 module.

AF: Were you asked to both help with the design and production? 

MJ: BGI’s role was primarily to execute a specified design. However, our suggestions for improvements were well received. That is a testament to ISRO’s team because they are very receptive to areas of improvement. 

AF: What were some of the biggest technical challenges you and your team faced? What were some of the central constraints to which you had to find solutions? 

MJ: One of the challenges was the material we needed to work with. The material was difficult to machine and wore out the tools rapidly. This in turn affected the ability to maintain the close tolerances the parts required so we had to modify our machining strategy. It is fair to say it took far longer than anticipated to machine the prototypes. However, this modified strategy helped immensely in the final part production. 

AF: Can you tell us what it’s like being involved in such a momentous project for your company and your country, but also for the benefit of the world at large? 

MJ: As in any other project, it is always teamwork. Not only within our company but also with the customer. First, we must understand that this is unchartered territory, and yet the product must be absolutely fail-safe. It’s only the successes that are known, but a number of times one must fail to understand the concept of success in these cases. Finally, it is like doing a trapeze act without a net. The audience is not only India but the world at large. Therefore, the serious commitment to ensure that there is no chance of failure was prime. In this case, it was a combination of our talent and the right combination of high-end machines that ensured the result. 

In many such cases, we do our best to ensure that India has the talent to do such jobs. Also, an important point to note is that just as the saying goes: “talent is nothing without opportunity.” We are grateful to ISRO for having given us this opportunity to prove our and the country’s capabilities. On a global level, this makes a huge statement for us and our country. A recognition for us being a manufacturer who has the capability to take on fail-safe products and the world to know that India is second to none. Import of such parts will no longer be required and on the contrary, we can look forward to exporting such critical parts. Our ship has arrived in the true spirit of Aatmanirbhar Bharat. [Aatmanirbhar Bharat translates to “self-reliant India,” a phrase Indian Prime Minister Narendra Modi and his government use to describe the country’s plans for economic development.] 

AF: Given that the lunar landscape has its own set of challenges, how have your gears performed under those circumstances? 

MJ: The lunar landscape imposes constraints that render some of our basic everyday assumptions invalid. The south side of the moon experiences immense temperature variations and the parts and subassemblies all had to weather these extremes for as long as possible. From all accounts, the program has been a great success, and all the tasks assigned to the rover were completed successfully. Now we have to wait and see if the rover can “wake up” and be mobilized again once the south side of the moon sees the sun again.  

AF: What are your thoughts about the prospect of gear technology and space explorations for the future? 

MJ: Emerging technologies such as 3D metal printing will play increasingly significant roles. The ability to print the parts you need on-site without holding any inventory is immensely appealing and practical. We have seen how the transition to EVs accelerated the adoption of higher specification gears, albeit fewer per assembly. Similarly in other aspects of space and airborne vehicles, gears will certainly play a relative role though probably not as much as it has in the past. 

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An Inside Look at BGI’s Facilities 

BEFORE—BGI hangar in 2009. 

AFTER—The same hangar at BGI in 2023. 

CNC straight bevel grinding on the Gleason Phoenix 275G—presently the only machine in India with this capability. 

Gleason Phoenix 275G CNC bevel gear grinder with Curvic coupling and straight bevel options. 

Klingelnberg Oerlikon G27 CNC bevel gear grinder.