Flying with Manufacturing

The LRO will carry seven instruments to study the moon in addition to the LCROSS probe. Photo courtesy of NASA/Goddard Space Flight Center

When it comes to advancing space exploration, the sky is the limit at NASA’s Goddard Space Flight Center (GSFC), a place where studying black holes, conducting gravitational mapping of the moon, exploring Mars and Jupiter, and visiting the International Space Station propel science beyond possible thought.

Located in Greenbelt, MD, the GSFC designs, builds, and operates satellites and scientific equipment such as the Hubble Space Telescope, GOES weather satellites, LandSat earth imaging systems, the SOHO solar observatory, and many others.

A big part of the GSFC’s capabilities comes from its on-site Advanced Manufacturing Branch, which provides broad machining, fabrication, and assembly services via punches and press brakes, gaging systems, turning machines, and GF AgieCharmilles multi-axis high-speed machining centers. In addition, since the facility features in-house metal finishing, composite layup and curing, rapid prototyping, precision assembly, and more, there is not much the branch is unable to handle.

Matt Showalter, associate branch head for the Advanced Manufacturing Branch, code 547, often thinks of the facility as Goddard’s “temple of science and engineering.” He says, “It is a place for ideas to become reality. The branch’s motto, based on an old advertising logo, is ‘we bring concepts to flight.’”

The Mikron HPM1350U is one of four machines in a machining cell implemented at the NASA/Goddard Space Flight Center.

For nearly a decade, Showalter has been part of a team devoted to continuous improvement of Goddard’s manufacturing abilities. Showalter explains, “Our purpose here is to ensure that we have the capability and capacity to do anything that comes through the door. Prior to our initiative to modernize the shop, we were totally dependent on older systems and there were some things we just could not do. You can limit yourself from a science and engineering perspective if you do not put new technologies into your manufacturing.”

Before the modernization initiative began at Goddard nine years ago, one missing piece of the manufacturing puzzle was multi-axis high-speed machining. To that end, the Advanced Manufacturing Branch team has invested in Mikron multi-axis machining centers from GF AgieCharmilles. Starting with one Mikron HSM 600U machine seven years ago, the facility now has an impressive four-machine high-speed machining cell containing the original HSM 600U together with a Mikron HSM 400U, Mikron HPM 800U, and Mikron HPM 1350U.

Collaborative Efforts
Showalter explains that bringing in new machine tool technology is a collaborative effort, controlled by strict federal procurement regulations, where potential vendors receive invitations to show off their wares. Beginning with discussions about future needs of the engineers and scientists, and technical assessments by technicians from the shop floor, everyone contributes in developing the statement of work that defines the specifications for the necessary machine technology to meet the current and future requirements of the organization. It is not just a piece of equipment, rather a complete package of support, tooling, and training.

“When it hits the floor, we want it running and not waiting three years to tool it up,” Showalter says.

Today’s satellites and associated instruments are getting lighter and smaller, with modern satellites coming in at one-fourth the size of their older cousins.

“We have to minimize weight, because it is expensive to launch. As part features get smaller, our tolerances get smaller as well. And the high speed machining centers are critical to this work,” Showalter states.

With the capability of Mikron High Speed Machining (HSM) and High Performance Machining (HPM), the Advanced Manufacturing Branch is able to handle a variety of work.

“We machine anything from aluminum, titanium, Inconel, Invar, stainless steel, and high-nickel alloys…you name it,” Showalter says.

The Advanced Manufacturing Branch team at NASA/Goddard Space Flight Center has invested in Mikron multi-axis machining centers from GF AgieCharmilles, starting with one Mikron HSM 600U machine seven years ago.

From these materials, the Advanced Manufacturing Branch employees use the Mikrons to machine an expansive range of workpiece types, from components measuring 0.030" across with features as small as a human hair, all the way up to workpieces that would fill a 1m cube.

Designed to accommodate workpieces up to 9.05" x 13.77", the Mikron HSM 400U portal design provides simultaneous 5-axis machining in a compact footprint. Because of its reliability, traceability, and accuracy, the Mikron HSM 400U is an ideal solution for the Advanced Manufacturing Branch’s prototype work and mold construction. Additionally, the machine provides excellent surface finishes and precision part details while significantly reducing machining time for semi-finishing and finishing operations.

Based on a portal-type gantry design, the Mikron HSM 600U and Mikron HPM 800U 5-axis machines are built for high-performance machining applications, and for 100% full 5-axis simultaneous machining operations; the two machines feature direct drives in their circular and swiveling axes, which securely clamp in place for precision part positioning. Thanks to their unique designs and modularity, these machines provide the Advanced Manufacturing Branch with high-accuracy machining for both its single part production and rational series production.

The basis of GF AgieCharmilles’ Mikron HPM 1350U, on the other hand, is on a cross-bed-type design. The machine’s frame-shaped traveling column moves the spindle in the Y- and Z-axis travels, while the X-axis is in the table. This special design allows the Advanced Manufacturing Branch to eliminate problems associated with any superimposed machine movements.
 

The LRO will orbit the polar regions of the moon where it may have continuous access to sunlight and will be able to search some of the permanently shadowed areas of the lunar surface, which could contain water ice. Photo courtesy of NASA/Goddard Space Flight Center

Designing Better Parts
However, there is more to the story than high-performance and high-speed machining. The multi-axis capabilities of the Mikrons allow Goddard engineers to design better parts.

Says Showalter, “With the 5-axis system, we have the ability to take a multiple-component bracket or assembly configuration and make it into one part. We can go from plane normal to a reverse angle plane or compound angle plane and do everything in one workpiece and a single operation. So instead of stacked tolerances (as in a multiple-part assembly), our accuracies are controlled by a single reference coordinate system.”

One of the people using the Advanced Manufacturing Branch’s services is Adam Matuszeski, electromechanical engineer at NASA. Matuszeski was part of the group responsible for building the Lunar Reconnaissance Orbiter, or LRO, placed into orbit around the Earth’s moon in 2009. Designed to map out potential landing sites and gather information about the moon’s surface and geography, the LRO mission, slated to last only 14 months, is still successfully streaming data back to Goddard.

Circling the moon at an altitude of 30 miles, the LRO satellite carries seven high-tech devices designed to image the moon’s surface, measure radiation levels, and look for areas of frost, water, and ice, especially near the poles. Critical to the LRO’s success is always knowing the precise location of the spacecraft.

To accomplish this feat, scientists mounted a small telescope on the orbiter’s antenna dish.

Says Matuszeski, “The telescope looked through a hole in the dish, and was connected via fiber optics from the back of the telescope to a detector on the laser altimeter. Because it was going to the moon and taking very precise instrument data, it needed to have a way of knowing exactly where in space it was.

“The solution was a tiny telescope hidden behind the antenna dish and designed to give a laser-referenced measurement from earth,” Matuszeski explains. “It picks up a pulse of green laser light shot from a station at Greenbelt and measures the amount of time it takes to get from the earth to the LRO, indicating how far away the spacecraft is from earth.

“For this project, we had to run seven 0.25mm diameter fiber optics across the spacecraft. The trickiest part of that was machining the tip of the connector, called the ferrule. It is a 2.5mm cylinder that is hollow on one side, like a long thin cup about 17mm long. We milled a flower-shaped pattern in the end of the cup using a 0.006" end mill on our Mikron machine, which allowed us to locate those seven fibers, six on the outside and one in the middle, then affix them there with an epoxy and polish them flat,” Matuszeski explains.

With the LRO, NASA has already collected the same amount of data as all previous planetary missions combined.
 

The science team that oversees the imaging system on board NASA’s Lunar Reconnaissance Orbiter (LRO) has released the highest resolution near-global topographic map of the moon ever created. This new topographic map, from Arizona State University in Tempe, AZ, shows the surface shape and features over nearly the entire moon with a pixel scale close to 100m (328ft). A single measure of elevation (one pixel) is about the size of two football fields placed side-by-side. Photo courtesy of NASA/Goddard Space Flight Center

Complex, Little, Tough
Another of the seven devices riding aboard the LRO is LOLA, short for the Lunar Orbiter Laser Altimeter. LOLA is a complex little device, but in simple terms, her job is to generate a high-resolution 3D map of the moon, which will help scientists find the best place to land future spacecraft, or possible sites for solar power stations.

“LOLA uses what is called a LIDAR. It is like radar, but it uses a laser for detection and ranging to measure distance,” Matuszeski says. “However, the art of creating a laser that can fly in space is kind of a black art, and it is one of the things that our center at Goddard prides itself on. We have probably done five or six of them successfully over the last 15 to 20 years, and all of them were challenging.”

Matuszeski goes on to say that it is quite difficult to build a laser that will last years in space, not only because of the harsh environment, but also because it is impossible to make any physical adjustments after the device has left the launching pad.

To accomplish its difficult mission, LOLA depends on a tiny array of five fiber-optic lenses held in a precision-machined ferrule. LOLA fires a laser beam through this optical array, where it is broken into five separate beams, each of which bounces off the moon’s surface before returning to LOLA and being transmitted back to earth, allowing scientists to measure the surface variations and piece together a 3D map of the lunar surface.

Matuszeski explains that the five fiber optics – each just 0.1mm in diameter – were precisely placed in a cross pattern on the back of the telescope. “It kind of looked like the cross section of a clover leaf or club from a deck of cards. We were trying to machine that shape into a stainless steel ferule 2.5mm across.”

He further says, “All five of them had to be located within respect to the center of the pattern within 10µ to 15µ. The holes had to be slightly more precise than that, because otherwise the fibers could move around and bond in the wrong place. We used a 0.003" end mill running at up to 36,000rpm, and looked at the tool after every cut to check for wear. We would then adjust the next cut based on that. I do not think we could have done these particular parts on any other machines than a highly accurate 5-axis machining center.”

What Stays In, What Goes Out
It is tough machining work, to be sure. So why not outsource it? With today’s budget-cutting economy, would it not be easier and cheaper just to send this work out to a job shop, someone who specializes in this sort of work?

“In fact, the majority of the work that we do goes outside to our vendors,” says Showalter, in response to outsourcing work. “However, what I see as different from a job shop is that we are here to produce a part, sure, but we are also here to figure out the process. That is why we keep a lot of the tougher work in-house. When you are doing internal research and development or solving critical tolerance issues for a flight project, it gives you in-house control and feedback in real time for the development of that process.”

An artist's concept of LRO. Photo courtesy of NASA/Goddard Space Flight Center

That is because, aside from high precision and high-performance machinery, and the knowledge to operate it, building a spacecraft also requires a high level of collaboration.

Explains Showalter, “We look at this as a triangle – science, engineering, and manufacturing; you need science for the ideas of what you are going to do. Engineering determines the designs for the hardware. Nevertheless, nobody flies without manufacturing. There are three legs to the stool.”

According to Showalter, “At times we will go back to the machine and cutting tool vendors to get their input. We do not pretend to be the expert on everything. That is why we collaborate with the organizations that sell us the equipment. We do not want to go in and just buy a machine. The most value to us, the government, is the full package: is it the correct manufacturing technology, what does the machine cost, what does the training cost, are application engineers available when needed?”

These factors are important because the facility’s schedules are critical. When dealing with celestial events, there may be times there is only one chance for success.

“For instance, if we are involved in a project specific to a comet fly by, such an event may not have occurred in hundreds of years,” Showalter states. “Therefore, when we are involved with such once-in-a-lifetime events, meeting specified launch dates is mandatory. To do so, we will use all the resources available to us, including our machine tool suppliers.

“After the new machines were installed, GF AgieCharmilles came out and had both machines up and running in less than 10 days. Training began. We were bringing new folks into the cell. Because of that, we made calls and had applications support quickly queued up and on the phone whenever we needed it.”

Showalter says that level of support continues today, “We had a job that was kind of rushed and we needed support, and they sent an applications engineer out who was on site within 48 hours. Considering we had three new people coming into that group, that is pretty good. Pretty much, that is the standard. Anything we put on the floor, the expectation is that is what we want, and AgieCharmilles is quite aware of what we need, so they deliver it and meet our expectations every time.

“Overall, GF AgieCharmilles is a very responsive technical collaborator and has played a vital role for us,” Showalter comments. “We are looking to make Goddard a world-class, premiere manufacturing facility. That said, as the technology grows, we intend to grow with it. The days of buying a piece of equipment and keeping it for 25 years until its dead are gone.”

With the rapid change of technology, it is important that the facility can update the equipment at the end of its useful life.

Bill Cowan, sales associate with Tuckahoe, the GF AgieCharmilles Sales Agent that supplied the Mikron equipment to Goddard, supports that statement. “Something that is different here than in a lot of other government facilities is this: machines at Goddard are being utilized more consistently than what I see in a lot of private shops. Goddard works as teams that are all on campus, so production times are shorter and operations more efficient with less waste.”

For more than 50 years, the U.S. space program has been making important scientific discoveries, providing the raw stuff of high technology. It is not just about putting people in space. Aside from the obvious benefits of space technology – global positioning systems, weather monitoring, and telecommunication satellites, to name a few – there are also the everyday items often taken for granted: athletic shoes, water purification, smoke detectors, invisible braces, instant-read thermometers, pizza delivery boxes, and golf-ball dimples. The list goes on, and will continue to grow, as NASA and the talented people at the Goddard Space Flight Center continue to push the limits.

GF AgieCharmilles
Lincolnshire, IL
gfac.com/us

NASA Goddard Space
Flight Center (GSFC)
Greenbelt, MD
nasa.gov/goddard