While NASA says its support for a mission to Jupiter’s moon Europa is now aligned with Congress, project officials are preparing for a possible “squeeze” on mission funding in the next fiscal year.
In presentations at an Aug. 11 meeting of NASA’s Outer Planets Assessment Group (OPAG) in Flagstaff, Arizona, officials involved with what’s widely known as the Europa Clipper mission said they are looking for ways to cut costs in 2017 while keeping the mission on track for a 2022 launch.
“There is this squeeze in FY17 that we have,” said Bob Pappalardo, the mission’s project scientist at the Jet Propulsion Laboratory, said. “We’re asking the instrument teams and various other aspects of the project, given that squeeze, what will it take in the out years to maintain that ’22 launch. We’re actively pursuing that question as we speak.”
Pappalardo didn’t elaborate on the budget details, but the administration’s request for the mission in its 2017 budget proposal, $49.6 million, is far less than the $175 million it received from Congress in 2016. There is uncertainty in Congress as well: a House appropriations bill for fiscal year 2017 offers $260 million for the Europa mission, yet a Senate bill, while “supportive” of the mission, does not explicitly allocate any funds for it. Neither bill has been passed by either chamber.
The outgoing director of NASA’s Jet Propulsion Laboratory on Nov. 19 floated the idea of sending a small scout helicopter to the red planet along with the Mars 2020 sample caching rover headed there in 2020.
“It’s not approved for that mission yet, but we are doing the technology which will enable us to actually have a drone which will fly around the rover, survey the area in front of it and enable the rover to basically drive more efficiently,” JPL Director Charles Elachi said after a luncheon speech on Capitol Hill hosted by the Space Transportation Association. “So you’ll have a drone taking the survey and sending the data to the rover and having the rover avoid hazards.”
JPL has been touting its Mars Helicopter since January but has not before linked it to any particular mission. The drone would be solar powered and capable of flying for two to three minutes a day, according to a video JPL uploaded to youtube earlier this year.
A scouting drone could help the Mars 2020 rover avoid the sort of mission-ending misstep that got the smaller Spirit rover — the twin of the still-operational Opportunity rover — stuck in martian sand in 2009.
The Mars 2020 rover is charged with drilling martian surface cores, which it will leave on the ground for some future mission — or missions — to retrieve, package, and launch into space for eventual return to Earth.
Although the Mars Helicopter has not been confirmed as part of Mars 2020, JPL is pressing ahead with proof-of-concept tests.
“By March of next year — we’re actually building a full-scale helicopter, 1 kilogram size — we’re going to put it in a chamber and simulate, exactly, the Mars atmosphere,” Elachi said. “We have done some tests and we’re confident it will [fly].”
As demonstrated by the bumpy landing of ESA's Philae lander on comet 67P/Churyumov–Gerasimenko, exploring comets, asteroids, and small moons can be difficult due to their low gravity. Not only can landing on one be like trying to alight on a trampoline, but roving around their surfaces is next to impossible because the negligible gravity offers practically no traction. To overcome this, a team of engineers is developing Hedgehog, a completely symmetrical robot rover for low-gravity exploration that moves by hopping.
A joint project by NASA's Jet Propulsion Laboratory (JPL), Stanford University, and MIT, the Hedgehog robot gets around these limitations with an unusual form of locomotion that allows it to hop, tumble, skip, and even launch itself with artificial "tornadoes." Essentially a cube with horns or spikes on each corner, it has no right way up and every face is identical, so it doesn't matter how it lands. In addition, the cube shape makes it easy to pack economically in a spacecraft.
The technology to 3D print a single part from multiple materials has been around for years, but only for polymer-based additive manufacturing processes. For metals, jobs are typically confined to a single powdered base metal or alloy per object.
However, researchers at NASA’s Jet Propulsion Laboratory say they are in development of a 3D printing technique that allows for print jobs to transition from one metal to another in a single object. According the JPL researchers, these gradient metals have been created previously in a lab setting but NASA’s process is the first to make usable objects that take advantage of the mechanical and thermal properties of the various metals used.
“We’re taking a standard 3-D printing process and combining the ability to change the metal powder that the part is being built with on the fly,” said Douglas Hofmann, a researcher in material science and metallurgy at JPL, and visiting associate at Caltech. “You can constantly be changing the composition of the material.”
According to the researchers, the process is based on Laser Deposition technology, in which metal powder is injected into a high-powered laser beam that melts the surface of the target object to form a small molten pool. Powder applied to this pool is absorbed and leaves a deposit as thin as 0.005 in. thick. These densely bonded layers can then be used to either build or repair metal parts.
In JPL’s technique, the build material’s composition is gradually transitioned as the print progresses. For example, the powdered build material might contain 97 percent titanium alloy and 3 percent stainless steel at the beginning of the transition. Then, in 1 percent increments between layers, the gradient progresses to 97 percent stainless steel and 3 percent Ti alloy by some defined point in the overall 3D printing process.
The main benefit — in addition to testing the metallurgical properties of new alloy compositions – is to take advantage of the differing physical properties (i.e. thermal expansion, magnetism or melting temperature) of the two or more metals in one solid component, say the researchers.
