As NASA prepares to launch the first 3-D printer [...]]]>

Made In Space employees test a 3-D printer on a parabolic aircraft flight in 2013, prior to its launch to the ISS later this year. A new report concludes that the near-term benefits of 3-D printing in space have been exaggerated. (credit: Made In Space)

As NASA prepares to launch the first 3-D printer for the International Space Station (ISS), a report released today says that while the technology may have considerable long-term benefits, its short-term potential has been exaggerated.

The National Research Council report, “3D Printing in Space,” examined the current state of 3-D printing, also known as additive manufacturing, and its potential applications in space. The report, sponsored by NASA and the US Air Force, concluded that the technology has benefits, but not necessarily in the immediate future.

“Many of the claims made in the popular press about this technology have been exaggerated,” said Robert Latiff, chair of the committee that prepared the report, in a statement accompanying the report. “For in-space use, the technology may provide new capabilities, but it will serve as one more tool in the toolbox, not a magic solution to tough space operations and manufacturing problems.”

The report echoes Latiff’s comments. “The specific benefits and potential scope of additive manufacturing remain undetermined, and there has been a substantial degree of exaggeration, even hype, about its capabilities in the short term,” the report states. “The realities of what can be accomplished today, using this technology on the ground, demonstrate the substantial gaps between the vision for additive manufacturing in space and the limitations of the technology and the progress that has to be made to develop it for space use.”

The concept of using 3-D printing in space has been attractive to some within NASA and industry for some time. A 3-D printer on the ISS or future spacecraft could, for example, simplify the logistical challenges of stocking spare parts by allowing crews to print replacement parts as needed from a common “feedstock” of material, like plastic or metal. Others have argued that 3-D printing could be used to manufacture structures or even entire spacecraft not possible on the ground.

The report notes that long-term potential for 3-D printing, and recommends that future uses of the technology be evaluated not just on its ability to lower costs but also to enable new capabilities. There are many challenges, though, associated with those capabilities, including difficulties getting 3-D printing to work in the microgravity and vacuum environments of space. Additive manufacturing also has significant power requirements, the report notes, and requires a stable platform free of significant vibrations, both challenges in space.

The report does make a number of recommendations for NASA and the Air Force to support 3-D printing applications. For NASA, those recommendations include identifying research projects for the short and medium term, particularly on the ISS. It also recommends NASA create “an agency-wide space-based additive manufacturing working group” to develop a technology development roadmap for 3-D printing that stretches out as far into the future as 2050. The Air Force, whose interest in 3-D printing in space is not as well established as NASA’s, should take similar steps to identify uses of the technology and experiments that can be flown in space to demonstrate it.

The release of the report comes as NASA prepared to launch the first 3-D printer designed for use on the ISS. That printer, developed by Silicon Valley startup Made In Space, is slated to fly on the next SpaceX commercial cargo flight to the ISS, currently scheduled for launch no earlier than September 12.

Jason Dunn, co-founder and chief technologist of Made In Space, said at the Future Space 2014 conference Thursday in Washington that the printer is completed and in NASA’s hands for eventual loading on the SpaceX Dragon spacecraft that will fly to the ISS. That printer is the first step in the company’s long-term goal in eventually being able to manufacture nearly anything in space, getting around the “bottleneck” of space access.

“This printer will be the first thing to ever manufacture anything off Earth,” he said. “It represents the beginning of a long path towards expanding our presence in space.”

When you think of hybrid engines, what typically comes to mind is the hybrid rocket motor developed for SpaceShipOne that powered it to the $10-million Ansari X PRIZE in 2004, [...]]]>

An earlier test of a 10-inch hybrid rocket motor by SPG. The company plans to test a larger 22-inch motor on Friday. (credit: SPG)

When you think of hybrid engines, what typically comes to mind is the hybrid rocket motor developed for SpaceShipOne that powered it to the $10-million Ansari X PRIZE in 2004, and its larger successor, RocketMotorTwo, under development today for SpaceShipTwo. Both those hybrid motors use a combination of liquid nitrous oxide and solid hydroxyl-terminated polybutadiene (HTPB) as propellants. Beyond that application, though, hybrids have seen little use in launch systems.

With a test firing later today, though, a small California company hopes to demonstrate an alternative hybrid engine technology that it believes addresses some of the issues associated with more conventional hybrid motors. Space Propulsion Group (SPG) plans to test-fire a motor 56 centimeters (22 inches) in diameter at its test site in Butte, Montana. That test is planned for 10 am local time (12 pm EDT), and the company plans to webcast it. (Update: I’m told that they’re having technical difficulties with the live web feed.)

“There’s this perception out there that hybrids combine the worst of the two worlds” of solid- and liquid rocket engines, SPG president and CTO Arif Karabeyoglu said during an interview at the company’s Sunnyvale, California, headquarters last week. “There are some hybrids that will do that, but what we’re saying is that we have other technology that doesn’t have the old, bad virtues of the classical hybrids.”

The key difference between SPG’s motor and other hybrids is the choice of propellants. SPG uses liquid oxygen for its oxidizer and paraffin for its solid fuel. This retains a key advantage of hybrids—safety—but offers solutions to a couple of issues with more convention hybrids. One such issue is their low “regression rate”, or the rate at which solid fuel burns away. This requires some complex designs for the fuel in order to increase the surface area of the fuel exposed to the oxidizer. These designs include some intricate “wagon wheel” geometries that can create some issues of their own regarding the structural stability of the motor as it burns, including chunks of fuel coming loose.

Replacing HTBP with paraffin eliminates this problem, Karabeyoglu said, because it has a much higher regression rate. The “wagon wheel” and other complex designs can be replaced with a simple, single port down the middle of the motor. He said they have also tweaked the design of the motor to address low-frequency instabilities, another issue with hybrids.

Using paraffin also has cost advantages. “The advantage of the paraffin is that it’s dirt cheap,” Karabeyoglu said. “You can’t find anything cheaper than that. It’s actually less expensive than gasoline.” They buy ordinary paraffin in bulk from candle suppliers and cast it into cylindrical motors in a relatively simple process at their facility, located in a nondescript industrial park just off the 101 Freeway in the heart of Silicon Valley.

Work on the LOX-paraffin motor, including some earlier, smaller 25-centimeter (10-inch) designs, has been funded in part by the Air Force through SBIR awards. With the upcoming tests of the 22-inch motor, SPG hopes to demonstrate the capabilities of this alternative approach to hybrids and open up some opportunities for future business. The company has already looked at using this motor as part of an air-launch system as well as a ground-launched smallsat launcher that could place 100 kilograms into LEO for $2.5 million.

“It’s time to transition this technology to a product,” he said. “We were not ready last year to talk to people, because we did not have a viable solution. Now we do.”

Dan Rasky of NASA Ames presented on the status of their Commercial RLV Technology Roadmap Study, seeking to identify what technologies needed for such vehicles (both suborbital and orbital) are of most interest to industry. The full details [...]]]> [The first in a series of posts from the Space Access ’10 conference this week in Phoenix.]

Dan Rasky of NASA Ames presented on the status of their Commercial RLV Technology Roadmap Study, seeking to identify what technologies needed for such vehicles (both suborbital and orbital) are of most interest to industry. The full details of the effort are in his slide presentation, posted here by popular request. The goal, he said, is to have an interim roadmap ready to present at the NewSpace 2010 conference in July at NASA Ames; the final version will be out in September.

One interesting note from the presentation: Rasky said that NASA Dryden recently acquired the two airframes from the canceled X-34 program. They had been in storage since the program’s cancellation when a Dryden employee bought them for $1 each from Orbital Sciences, but when he retired the airframes were dragged out to the bombing range at Edwards AFB. Fortunately the airframes were recovered intact, although several crates of other X-34 parts were lost. Rasky said his office is trying to get some funding to study the airframes and determine their potential viability for future integrated flight tests, something the roadmapping study has found considerable interest for so far.

Our first stop is Davos, Switzerland, where Space Adventures’ Eric Anderson says “business is good” for the space tourism company. Anderson, attending the World Economic Forum, said he’s looking for additional customers, but potential clients “should not expect any bargains because of the global financial [...]]]> A roundup of space tourism news from across the globe:

Our first stop is Davos, Switzerland, where Space Adventures’ Eric Anderson says “business is good” for the space tourism company. Anderson, attending the World Economic Forum, said he’s looking for additional customers, but potential clients “should not expect any bargains because of the global financial turmoil.”

While we’re in Europe, check out a Flight International report on new European vehicle studies funded by the EU’s Future High-Altitude High-Speed Transport (FAST) 20XX program, to the tune of nearly $10 million. The effort is looking at two concepts: a relatively near-term (circa 2015) suborbital vehicle and a long-term hypersonic point-to-point transport. (How long term? Try 2075.) The funding is only for early-stage technology studies; where the money would come from for further development, even of the suborbital vehicle, is unclear.

The prospects for space tourism in China is examined in an Asia Times article this week. Industry officials agree that there’s tremendous potential in the Chinese market given its size, but for US companies export control restrictions would make it difficult to do business there. Also, the lack of a commercial space regulatory framework in China would hinder any effort for a domestic space tourism industry to develop.

There is, though, interest in space tourism in Mexico. The English-language Guadalajara Reporter said that an anonymous local businessman has signed up to fly with Virgin Galactic, becoming the first person from Mexico’s second-largest city to reserve a flight to space. Viajes Capistrano, the tourist agency who is one of five in the country that sells Virgin Galactic trips, is planning to make a bigger push for clients in the city in coming weeks.

Advanced Composites Group Ltd. (ACG, Heanor, Derbyshire, U.K.) will supply a new generation of out-of-autoclave prepregs for the project, featuring MTM45-1, a variable-cure temperature, high-performance, toughened epoxy matrix developed for resin film infusion and prepreg processing. It was designed for low-pressure vacuum [...]]]> The trade publication High-Performance Composites offers this news about the development of SpaceShipTwo:

Advanced Composites Group Ltd. (ACG, Heanor, Derbyshire, U.K.) will supply a new generation of out-of-autoclave prepregs for the project, featuring MTM45-1, a variable-cure temperature, high-performance, toughened epoxy matrix developed for resin film infusion and prepreg processing. It was designed for low-pressure vacuum bag processing and, in addition to resin film and prepreg formats, is available in partially or selectively impregnated formats to reduce layup time, surface defects and internal voids. After a freestanding postcure, the system is capable of 150°C (302°F) wet Tg and reportedly exhibits good damage tolerance. Initial cure can be as low as 80°C/176°F, which ACG says allows for the use of lower cost tooling materials.

But you all knew that already.