“The next giant leap has begun.” So says the slogan for Constellation, NASA’s current human exploration program for the moon and Mars.
When Constellation first began in 2004, JPL was seen as a center whose focus was solely on robotic exploration. But with approximately 150 JPLers now engaged in Constellation and exploration technology programs, the Lab has shown it can contribute to human spaceflight as well.
“JPL leadership strongly supports the Lab being an active partner in NASA’s human spaceflight activities,” noted JPL’s Brian Muirhead, Constellation’s chief architect. “It’s also recognized by NASA that JPL has unique skills and experience that are extremely valuable to the development and the ultimate success of the Constellation Program.”
Throughout Constellation’s development process, JPL has provided technical and leadership talent involved with program-level system engineering; software, test and evaluation; Altair system design; and mission operations system engineering.
Constellation’s integrated architecture calls for the use of an Ares I rocket to launch a four-person crew in the Orion capsule into a low-Earth orbit, where it will rendezvous with the Earth departure stage and the Altair lunar lander vehicle, launched by an Ares V. The Orion docks to the Altair lander and the pair is sent on a trajectory to the moon by the Earth departure stage. The Orion/Altair vehicles enter low-lunar orbit, from which the Altair then descends to the moon surface with the crew. After the crew completes their tasks, they are carried back to the orbiting Orion by an ascent stage, much like Apollo. A second, uncrewed version of the Altair is capable of carrying a 15-metric-ton payload to the moon’s surface for building up an outpost.
Constellation is the largest-scale architectural project NASA has been involved in for decades, and with it comes large-scale engineering problems that JPLers are eager and ready to solve, according to John Baker, ascent abort phase system engineering lead. “The issues are very different than what we typically run into on our space missions,” he said. “It’s broadened our engineering exposure.” The Lab is providing leadership in solving some key Ares I rocket ascent issues, according to Baker.
In addition, JPL is assisting with the guidance, navigation and control of the Altair landers and is running operations integration for lunar surface systems. JPL is also working on landing risks and safety, including making recommendations for better parachute systems. Many designs have come about after carefully studying the Apollo missions and assessing the risks their engineering teams were both aware and unaware of at the time, noted Michael Sander, manager of JPL’s Exploration Systems and Technology Office.
Another part of NASA’s human spaceflight effort is the Exploration Technology Development Program, where JPL is leading the team for the All-Terrain Hex-Limbed Extra-Terrestrial Explorer (or ATHLETE), a cargo transporter for the moon capable of carrying up to 15 tons. A vehicle with six wheeled legs designed to stand 8 meters tall, Athlete would serve several functions on the moon: removing cargo—primarily habitats—from landers, transporting cargo, relaying communication, providing power through solar arrays and repositioning landers to better locations.
JPLers are currently advancing ATHLETE by essentially cutting the hexagon-shaped vehicle into three pieces—a center rectangle that becomes an interchangeable cargo pallet and two triangular wings, each of which has three legs with a wheel. The two “tri-ATHLETEs” can pick up a cargo pallet on top of a lunar lander and carry it to any desired place, even setting it down on the lunar surface.
Part of what makes ATHLETE so unique is its mix of wheel and leg technology, according to principal investigator Brian Wilcox. ATHLETE’s small wheels are designed to navigate normal lunar terrain and cannot traverse the small percentage of very soft or very rocky ground—that’s where the legs come in. Ames Research Center is developing the software for walking.
This mixed structure actually creates a lighter—and therefore slightly less expensive—overall system than a purely wheeled or a purely legged vehicle, Wilcox said. All-wheel vehicles like the Mars Exploration Rovers and Sojourner used bigger wheels and wheel actuators, which helped them get through extreme terrain but also weighed about six to eight times more than Athlete’s smaller wheels and wheel actuators. “The savings in mass actually pays for the whole rest of the leg, with savings left over,” Wilcox said.
A field test is scheduled for September to demonstrate the tri-ATHLETEs’ ability to lift cargo. And while no decisions have been made, most scenarios for the Constellation architecture call for anywhere from one to four pairs of these vehicles. “We serve a role in the architecture that no other system can compete with at this time,” said Wilcox.
Also through the technology program, JPL is leading the development of a new generation of space-qualified lithium ion batteries, doubling their specific capacity. The Lab is testing other developments too, notably actuators that can operate at minus 230 degrees C (minus 382 F).
The International Space Station is another part of the human spaceflight program that JPL is engaged in, including proposing new ideas for payloads. Out of 20 ideas, 11 were picked for initial discussion and seven were formally presented for consideration, Sander said. The Lab’s ideas have been well received and the prospects for the various payloads are hopeful, he added.
“A lot of this activity is starting up now because the ISS is within two years of being completed, and even at its current state has many sites to accommodate payloads,” said Sander. “The point is that ISS has a lot of payload accommodation capability. JPL engineers and scientists have identified some really good ideas, and we think the well is far from being dry.”
Indeed, JPL is no stranger to the space station, having previously developed the Electronic Nose and Vehicle Cabin Atmosphere Monitor.
Currently, the Lab is partnering with Johnson Space Center in creating an avionics subsystem, called the ISS to the Crew Exploration Vehicle Communications Adaptor (or ICCA), which will enable reliable, autonomous communication between the ISS and Orion during proximity and docked operations. The device is like a “router in space,” adapting the newer communication methods of Orion to the older communication of the station, said JPL Project Manager Caroline Racho. The adaptor is still in its formulation phase, but the development of its hardware is based on a heritage design used in other flight payloads such as the Moon Mineralogy Mapper and Electra radios.
Another exciting prospect for the ISS is the High Definition Television Testbed, a next-generation, high-definition camera put in a pressurized cylinder and remotely operated from the ground. Although the final decision for the go-ahead on funding is pending, JPL is still optimistic, said Sander.
The future direction of Constellation may be impacted by the options being developed by the federally chartered Review of the U.S. Human Space Flight Plans Committee. The advisory body, headed by Norman Augustine, former Lockheed Martin CEO, is looking at all aspects of the human spaceflight program including NASA’s exploration architecture and future utilization of the International Space Station beyond 2016.
“Norm Augustine is a very thoughtful person to run this committee, and that says something about its credibility and hopefully its results,” said Sander.
The Augustine Committee is holding public meetings throughout the summer. It is expected to release a report by mid-August, and Sander indicated that the committee’s decisions could affect NASA’s FY10 budget.
“We’re planning in 2010 and beyond to engage in even more strategic ways how JPL can provide more discernable deliverables in areas such as software, test and verification, and mechanical systems,” Muirhead added.
Story by Alex Abels Republished with permission from Daily Planet, JPL’s intranet news website.