Fourteen seconds. That is the amount of time that the crew of Apollo 13 was instructed by NASA’s Mission Control to fire their Lunar Lander’s descent engine to return their damaged spacecraft back to Earth. With the ailing spacecraft being 60-80 miles off-course, this was the critical “push” that the crew needed to correct their return trajectory. The inside of the command module was close to freezing due to most onboard systems being shut down to conserve energy, including the onboard digital timer. With the odds stacked against the crew, it was up to a mechanical backup to time the engine burn – – Astronaut Jack Swigert’s Omega Speedmaster wristwatch. While the availability of a backup seems so obvious as to be an afterthought, it was in fact a decision that had been qualified by NASA five years earlier.

Flight qualification is a process by which components intended for space are subjected to a variety of conditions intended to replicate the harsh environment outside the atmosphere, not limited to vacuum, temperature, and shock. These tests are designed to push systems to their very limits to ensure functionality, an achievement that ThinGap motors have accomplished in support of an upcoming NASA mission.  Qualifying anything for use in space, whether it be a ThinGap brushless DC motor or a commercially made Omega wristwatch, is an important and complex process.

The story of the watch that saved Apollo 13 began nearly a decade earlier, with Mercury-Atlas 8 in October 1962. In the early days of manned spaceflight, astronauts were not issued watches, and instead were permitted to wear their personal timepieces. For Mercury-Atlas 8, test pilot and astronaut Wally Schirra wore his Omega Speedmaster, beginning what became a long relationship between Omega Watches and NASA.

With America’s lofty goal of fulfilling recently assassinated President John F. Kennedy’s dream of landing a man on the Moon by the end of the 1960s, no detail was overlooked, including the astronauts’ watches. By the time NASA was ready to select a watch for the Apollo program in 1965, they issued a solicitation to a handful of watchmakers based off of astronaut feedback, with ultimately only three makers responding: Omega, Rolex, and Longines.

With the three brand of watches procured for evaluation, it came time to test them in the most scientific way possible… to destruction, with the following flight certification regiment having been pulled from historical documents:

1. 1. 1. High Temperature– 48 hours at a temperature of 160°F (71°C) followed by 30 minutes at 200°F (93°C). For the high temperature tests, atmospheric pressure shall be 5.5 psi (0.35 atm) and the relative humidity shall not exceed 15%.
      2. Low Temperature –Four hours at a temperature of 0°F (-18° C)
      3. Temperature Pressure Chamber – pressure maximum of 1.47 x 10exp-5 psi (10exp-6 atm) with temperature raised to 160°F (71°C). The temperature shall then be lowered to 0°F (-18°C) in 45 minutes and raised again to 160°F in 45 minutes. Fifteen more such cycles shall be completed.
      4. Relative Humidity –A total time of 240 hours at temperatures varying between 68°F and 160°F (20°C and 71°C, respectively) in a relative humidity of at least 95%. The steam used shall have a pH value between 6.5 and 7.5.
      5. Pure Oxygen Atmosphere –The test item shall be placed in an atmosphere of 100% oxygen at a pressure of 5.5 psi (0.35 atm) for 48 hours. Performance outside of specification tolerance, visible burning, creation of toxic gases, obnoxious odors, or deterioration of seals or lubricants shall constitute a failure. The ambient temperature shall be maintained at 160°F (71°C).
      6. Shock –Six shocks of 40g each, in six different directions, with each shock lasting 11 milliseconds.
      7. Acceleration –The test item shall be accelerated linearly from 1g to 7.25g within 333 seconds, along an axis parallel to the longitudinal spacecraft axis.
      8. Decompression –90 minutes in a vacuum of 1.47 x 10E-5 psi (10 E-6 atm) at a temperature of 160° F (71° C), and 30 minutes at a 200° F (93°C).
      9. High Pressure –The test item shall be subjected to a pressure of 23.5 psi (1.6 atm) for a minimum period of one hour.
      10. Vibration –Three cycles of 30 minutes (lateral, horizontal, vertical, the frequency varying from 5 to 2000 cps and back to 5 cps in 15 minutes. Average acceleration per impulse must be at least 8.8g.
      11. Acoustic Noise –130dB over a frequency range from 40 to 10,000 HZ, for a duration of 30 minutes.

As if the torturous and destructive test routine wasn’t enough, the watches were subsequently required to retain their accuracy within 5 seconds a day. The Speedmaster was the winner by default, with the Longines and Rolex having failed at the beginning of the first temperature test. Despite being the victor, the Speedmaster was still worse for wear, with all the luminous paint on the dial having crumbled off, yet its workings remained accurate to within an impressive 4 seconds a day.

The Omega Speedmaster has changed very little cosmetically since it’s 1957 introduction

The reasons for the Omega Speedmaster’s durability ultimately comes down to a simple, yet robust mechanical movement inside, as well as a rugged, yet elegant case that envelops it. Introduced in the late 1950s for use in motorsports, the Omega Speedmaster is a hand-wound chronograph (a watch with an integrated stopwatch function) with a minimalist black dial with white markings and protected by a domed bubble acrylic watch glass. The Speedmaster had become a favorite amongst pilots due to the highly reliability, legibility, and most importantly, the accuracy it possessed.

Ed White on a spacewalk during Gemini 4

With the Speedmaster now qualified for all manned space missions and extravehicular activities, they became standard issue to NASA’s crews.  In June 1965, Ed White wore his on the first American spacewalk during Gemini 4. When Apollo 11 landed on the Moon in July 1969, mission commander Neil Armstrong left his in the Lunar Lander to serve as a backup timer as the Lander’s internal electronic timer had malfunctioned. However, Buzz Aldrin chose to affix his for the moonwalk, making the Speedmaster the first watch worn on the Moon.

Buzz Aldrin in the Lunar Module ahead of lunar landing

Despite its previous widescale acceptance by the aeronautical community, the Speedmaster’s defining moment came during Apollo 13 in April 1970, after an exploded oxygen tank crippled the Apollo Lunar Module en-route to the Moon. With their vehicle critically damaged, making their lunar mission impossible, the astronauts agreed to forsake all creature comfort, and powered down all support systems, except for basic life support, including the digital mission timer to save power. Jack Swigert’s manual 14 second burn, timed on the watch, ensured that their freezing capsule re-entered the at the right angle, instead of their trajectory which would have bounced them off the Earth’s upper atmosphere and back into space.

Astronaut Jack Swigert during spacesuit fitment

The Speedmaster flew with NASA for the rest of the Apollo moon missions, and subsequent NASA programs. When Apollo-Soyuz, the first international space flight, flew in 1976, both the American astronauts and Soviet cosmonauts were seen wearing Speedmasters–an interesting detail given that cosmonauts had previously worn exclusively Soviet-made watches as a way to promote their domestic industry and were regularly worn aboard the Mir Space Station.

The Speedmaster was re-certified by NASA in 1978 for the Space Shuttle program, yet again undergoing the same rigorous regime. Through the Shuttle program, the Speedmaster remained standard issue for all astronauts, and in the 1990s, NASA and Omega collaborated on a clean-sheet watch, designed with the needs of modern astronauts in mind. This joint venture resulted in the Speedmaster X-33, which saw the purely mechanical watch upgraded to a modern, battery-powered computerized watch. Despite being superseded by a modern replacement, the original Speedmaster has still been seen worn aboard the International Space Station.

German Astronaut Alexander Gerst is seen wearing his Speedmaster X-33 aboard the International Space Station

To this very day, one can walk into a jeweler and buy a watch that is cosmetically and functionally identical to what has been flown since 1962. In fact, from the mid-1960s onward, the caseback of every Omega Speedmaster Professional (affectionately referred to as the Moonwatch) bears the inscription “Flight-Qualified By NASA In 1965 For All Manned Space Missions-The First Watch Worn On The Moon”.

1970s Omega print ads detailing the Speedmaster’s involvement with NASA and the Apollo program

ThinGap has supplied flight-qualified motors to NASA in support of their upcoming PACE mission. Focused on monitoring the overall health of worldwide oceans and atmosphere by monitoring the color of the seawater, PACE is set to launch in February 2024 from Kennedy Space Center. ThinGap is honored to support this mission by supplying custom LS Series slotless motors that drive the satellite’s primary sensor, the Ocean Color Instrument. Additionally, ThinGap has supplied more than 2,500 motor kits in support of a major commercial constellation.

Works Cited:

OMEGA and Apollo 13 – The 14 critical seconds between success and failure

NASA Testing Regime for the Omega Speedmaster Moonwatch

Apollo 13 — A Life-Saving Fourteen-Second Burn Timed With The Omega Speedmaster Professional

A Watch Made for Space but Ready for Anything

Actual Pictures Actually Showing The Speedmaster Professional Actually Being Used For EVA, Today (Well, In 2014)

Watches used in space exploration

Designed around a low profile cogless motor with an optical encoder, precision bearing set, and anodized aluminum housing, the unit is for use in a ground-based NASA optical platform.

ThinGap recently shipped a housed version of its LSI 267-32 motor kit to a commercial customer in support of a ground-based NASA application, adding to the list of successful deliveries of housed units. Built around the company’s slotless 267 mm outer diameter BLDC motor kit, the H-LSI 267-32 integrates the high performance motor with a precision bearing set, and an optical encoder into a lightweight, Chem Film coated aluminum housing.

As a turnkey solution designed for a ground-based optical platform, this unit adds to ThinGap’s repertoire of housed and framed motor assemblies. The assembly measures 282 mm in diameter, with an axial height of 86 mm, and an internal aperture of 190 mm; the whole assembly weighs in at 8.34 kg (18.4 Lbs.), and produces a continuous torque output of 12.5 N-m, with a peak 1-second torque of 184 N-m.

Customers often come to ThinGap in need of a motor kit, wanting to take advantage of the low-profile, lightweight, and frameless architecture that is ideal for deep system integration. Yet, the time and cost of developing a housed solution are not lost on program managers and developers, so the availability of a ThinGap-led, fully engineered direct drive assembly provides a tangible advantage.

Beyond zero cogging, ThinGap’s air core motor kits have near zero Eddy current, and a harmonic distortion of less than 1%, so torque output is directly proportional to current. The resulting smooth motion and linear output makes them perfect for use in precision applications. ThinGap’s LS Series of slotless motor kits range in size from 25 to 267 mm in diameter, torque from 0.1 to 12 N-m continuous, and voltages from 24-400 volts.

For additional information on custom motor development, please contact the company at [email protected] or visit www.thingap.com.

As part of regular documentation updates, ThinGap recently outlined the process by which commercial-off-the-shelf motor kits are modified for space applications. Titled “ThinGap Space Qualification Capabilities Statement,” and available on the Compliance Information page, this one-page document provides an overview on how the company handles modifications to meet the needs of both LEO applications typical of NewSpace, as well as more rigorous Government space programs, including NASA and defense applications.

ThinGap’s brushless DC electric motor kits are high quality, high performance motion components. The company has an extensive space heritage with commercial, scientific and military programs, including 2,500 motor kits supplied for an undisclosed LEO satellite constellation, 20+ space-grade programs actively being supported, and delivery of flight-grade kits for NASA’s PACE Program.

ThinGap has a standard approach and delivery set for providing space-grade motors, as well as the capability to support more stringent customer-specific flow downs, in addition to offering the space-rated off-the-shelf TGR Series.

Commercial Space Standard

ThinGap has established a commercial standard to provide “space-grade” motor kits using a set of process and material callouts. Essentially any of ThinGap’s standard motor kits can be upgraded to a space standard. The defined space upgrades provide an affordable option, especially for high volume and rapid reaction programs, such as commercial LEO applications.

The baseline for commercial space motor kits includes the following:

• A controlled Materials and Processes (M&P) list
• Use of low outgassing materials, per NASA guidelines
• Class 3 PCBs
• Leaded solder and IPC J-STD workmanship
• Raw material certifications
• First Article Inspection Reports

Additional Supplemental Deliverables

ThinGap can quote a wide range of customer requested flow downs applicable to motor deliveries. When requested, the company can engage third parties to satisfy requirements outside its on-site capabilities, including certain types of testing and analysis. Optional customer requested deliverables include i.) structural and finite element analyses, ii.) on-site source inspection, iii.) DFARS compliant material sourcing and iv.) thermal vacuum testing conducted by a third party.

At the time of quoting, ThinGap requests a customer-provided compliance matrix with any required callouts or flow downs to be completed and returned by ThinGap.

Summary

The company prides itself on its heritage and being able to support a range of requirements called for by space applications.  Default deliverables are the baseline of the company’s capabilities, and can be supplemented with additional customer-specific requirements as required.

To view and download the statement, click here.

ThinGap was pleased to learn of the acquisition of Sierramotion by its parent company Allient, formerly known as Allied Motion Technologies. Sierramotion is a company that ThinGap has a solid history of working with to provide tailored mechatronic solutions for customers in the robotic, medical, defense, semiconductor, and industrial fields.

John Baumann, President of ThinGap commented “I see lots of potential officially being on the same team as Sierramotion, and expect to work even more closely with them going forward.”

Sierramotion and ThinGap’s working relationship was first announced back in 2019 and has been mutually beneficial ever since.  Sierramotion even mentioned ThinGap’s LS Series as a market leader in direct drive motors on their website back in 2021. With such a shared history of collaboration, this news offers great potential for the future.

With an outer diameter of 146 mm, the LSI 146-16 fits between the LSI 130 and LSI 152 motor kits

The axial height of the newest addition to the LS Series is only 16 mm tall

ThinGap continues to build out its LS Series of slotless motor kits with the latest release, the LSI 146-16. The new LSI 146-16 kit has an outer diameter (OD) of 146 mm, and an axial height of just 16 mm. With a total mass of just over 460 grams, it offers a continuous torque output of 1.48 N-m, and peak 1 second torque as high as 18.1 N-m.

Despite a maximum operating speed of up to 1,600 RPM, the LSI 146-16 was designed for use in slower speed gimbal systems, joining other LS Series models that have found uses in this application. Multi-axial gimbal systems leverage the benefits of high performance cogless Ring Motors, such as ThinGap’s industry leading LS Series, to directly drive movement and maintain position, while offering significant Size, Weight, and Power (SWaP) savings.

Using its proprietary thin wire-wrapped stators and optimized permanent-magnet rotors, ThinGap provides motors with specifications that can match the torque output of slotted motors, while avoiding the cogging, size and weight penalty that plagues them. ThinGap’s LS Series of slotless motor kits range in size from 25 to 267 mm diameter and torque from 0.1 to 12 N-m continuous and voltages from 24-400 volts.

Left to Right-Joseph Kay, PhD-Director of Engineering, John Baumann, President of ThinGap, and Robby Estep and Dustyn Strosnider from NASA Goddard Spaceflight Center

This past week, ThinGap hosted visitors from NASA who delivered their appreciation for the support of their PACE mission. The team from NASA Goddard gave a progress update on the mission, as well providing a Certificate of Appreciation that the ThinGap team can proudly display. NASA’s PACE mission is focused on monitoring the overall health of worldwide oceans by monitoring the color of the water, as well as atmospheric observation.  ThinGap is honored to support this mission by supplying custom LS Series slotless motors that drive the satellite’s primary sensor, the Ocean Color Instrument. NASA’s PACE Spacecraft is schedule to launch from the Kennedy Space Center in January 2024.

With the growing urgency for sustainable energy, pioneers are innovating new ways to harness the power of ocean waves.  Southern California based Ocean Motion Technologies is one of those pioneers. The company is developing a zero-emission energy solution using ThinGap’s motor technology in its generator mode.

Ocean Motion’s R&D is focused on sustainable, scalable, and more efficient marine hydrokinetic energy by focusing on small-scale applications like scientific & maritime buoys and moorings, offshore aquaculture, and coastal security and defense. Up until now, oceanic buoys have been powered by solar panels, which have a high cost of maintenance. Ocean wave energy is a natural choice for these use cases, but most wave energy devices are not designed for small-scale applications, as they can only function within a narrow range of sea states.

Leveraging SBIR Grants from the U.S. Department of Energy and National Science Foundation, Ocean Motion Tech has designed a wave generating prototype leveraging ThinGap’s TGD-108 (image). Originally designed and optimized for an aerospace application, the TGD-108 is available as a framed assembly with 1.4 kW of continuous power output while weighing only 670 grams or just less than 1.5 lbs.

With the adage that good motors make good generators, ThinGap’s technology is a logical choice for renewable energy applications that require overall system efficiencies. ThinGap’s unique scalable motor architecture and design offer efficiency up to 95%, and largely eliminates internal magnetic losses. The low impedance stator typical in ThinGap designs provides a stable, pure 3-phase sinusoidal, low-droop, with less than 1% harmonic distortion voltage output of clean, conditioned power.

Ocean Motion’s solution for powering data buoys is an adaptive wave energy device, with the ability to scale the technology up, and networking them together for oceanographic monitoring. The primary reason for pursuing marine power generation is due to the inherent energy density of ocean waves, which concentrates solar and wind energy and thus offering far greater energy potential in comparison.

With more than two decades of experience in the design and production of slotless motor kits, ThinGap salutes the novel efforts of customers like Ocean Motion Tech.  Ongoing and future projects designed to combine proven technology in an applied fashion are at the heart of innovative solutions like the ones being actively demonstrated in the Pacific Ocean.

Designed with airborne gimbals in mind, this new variant builds on the LS Series’ flight heritage

The 85mm OD fills the gap between the LSI 75 and LSI 105 standard models

ThinGap continues the expansion of its LS Series of slotless motor kits with the latest release, the LSI 85-13. The new LSI 85-13 motor kit has an outer diameter (OD) of 85 mm, and an axial height of just 13 mm, making it a little wider than 3 inches and roughly half an inch tall. With a total mass of 232 grams, it offers a continuous torque output of 0.324 N-m and a peak as high as 3.88 N-m.

The LSI 85-13 can operate at speeds of 0-1,760 RPM. Unique to the cogless nature of ThinGap’s slotless architecture, all of its motor kits can effectively operate across its entire range of speeds. Effective low speed is due to not needing to overcome the detent torque typical in a slotted or stepper motors.

Designed from the ground up for use in a gimbal system, the LSI 85-13 joins other ThinGap motors that have found homes in airborne applications. Multi-axial gimbal systems leverage the benefits of high performance cogless Ring Motors to directly drive movement and maintain position, while offering Size, Weight, and Power (SWaP) savings, which are all highly desirable traits. ThinGap’s LS Series of slotless motor kits is an industry leader for gimbal applications.

Using its proprietary, thin wire-wrapped stators, and optimized permanent-magnet rotors, ThinGap provides motors with specifications that can match the torque output of slotted motors, while avoiding the cogging that plagues them. ThinGap’s LS Series of slotless motor kits range in size from 25 to 267 mm diameter and torque from 0.1 to 12 N-m continuous, voltages from 24-400 volts, and current from 1 to 100 amps.

With the fast and aggressive build out of LEO constellations orbiting Earth, comes the pervasive need for free-space Optical Communications Terminals (OCT) that allow space-to-space, space-to-air, and space-to-ground connections. Point-to-point use of highly collimated light is critical to the utility of mesh networks connecting each spacecraft with each other and the ultimate users on the ground.

Satellites use gimbal mechanisms for the pointing and positioning portion of the Optical Communications Terminal (OCT), commonly referred to as the Coarse Pointing Assembly. Within the Coarse Pointing Assembly is a device called a fast-steering mirror that acts as the Fine Pointing Assembly that ensures a reliable optical connection.

Multi-axial gimbals, like those used in Coarse and Fine Pointing Assembly systems can leverage the benefits of high performance cogless Ring Motors to directly drive movement and maintain position. Frameless motor kits offer the further ability to integrate the actuation function as part of optimized systems, offering Size, Weight, and Power (SWaP) savings, which are highly desirable in spacecraft applications.

ThinGap’s LS Series of slotless motor kits is an industry leader for gimbal applications requiring high performance and efficiency, decisive move-and-hold positioning, and smooth motion for long-range target lock. LS motors have been widely used in OCT systems and even NASA’s PACE Mission’s optical scanner payload.

Using its proprietary design, thin wire-wrapped stators, and optimized permanent-magnet rotors, ThinGap provides motors with specifications that can match the torque output of slotted motors while avoiding the cogging that plagues them. ThinGap’s LS line of slotless motor kits range in size from 25 to 267 mm diameter and torque from 0.1 to 12 N-m continuous. With standard and modified configurations, the product line will cover voltages from 24-400 volts and current from 1 to 100 amps.

To learn more about the LS Series, click here.

With a focus on providing engineered solutions for a variety of high performance applications, ThinGap regularly provides modified versions of its off-the-shelf motor kits to meet customer specifications. Many of these changes include switching a motor’s winding configuration, space rating, high-temperature capability, or custom mounting configurations to create a modified-off-the-shelf product. In some cases, customers request an increase in axial height of an existing motor to improve the torque output of the motor kit without increasing the width.

Important to note that with ThinGap’s proprietary slotless motor architecture, torque increases exponentially with the outer diameter, but only proportionally with axial height. So while a larger outer diameter motor is always the better choice, customers often have mechanical constraints that limit their ability to accept a wider motor, making a taller product the next best solution.

ThinGap’s tooling is vertically modular, making it simpler and less expensive to change the axial height of a kit to improve torque output. Tall variants share much of the same material components with their smaller cousins, and can in many case be built in parallel. Many of ThinGap’s tall motor variants began as modified-custom solutions, such as the LSI 39-39, LSI 75-30, LSI 130-40, LSI 152-55, and LSI 267-58. By way of example, several motors sizes offer three different axial highest, such as the LSI 25 that is available in axial heights of 10, 16 and 25mm.

With two decades of experience in the design and production of slotless motor kits, ThinGap leverages its proven designs and analytical modeling that results in highly accurate transitions from predicted performance to real world operation. Furthermore, the process steps needed to produce motors of all sizes are highly scalable and ThinGap has standard products as small as 25mm, up to 393mm in outer diameter.

For a complete listing of our standard products, including our tall variants, please click here.