The lunar-crashingsecondary payload that will share an Atlas 5 launcher with NASA's LunarReconnaissance Orbiter has entered comprehensive performance testing about amonth ahead of schedule. That payload, the Lunar Crater Observation and SensingSatellite (LCROSS), is designed to gather data to help researchers determinehow much water-ice might be contained in lunar surface material.
Besides promising to puton an impressiveshow when two separate pieces of hardware plow into one of the Moon'spermanently shadowed craters in early 2009 at a speed of more than 9,000kilometers per hour, the LCROSS mission has been providing a great hands-on trainingexperience for a new generation of engineers.
LCROSS beat out 19 otherproposals in April 2006 to win $79 million in funding that was accompanied by astrict 1,000-kilogram mass allowance. The ultimate goal of the mission is tofind out once and for all whether the Moon's permanently shadowed regionscontain the water ice hinted at by findings from the Clementine and LunarProspector missions of the 1990s.
To do this resourcefully,NASA Ames Research Center and its industrial partner, Northrop Grumman SpaceTechnology, designed a mission that will send the Atlas 5's spent Centaur upperstage hurtling into the lunar surface while LCROSS ? a standard payload adapterring cleverly transformed into a fully functional science satellite ? observesthe impact, flies through the resulting plume of debris, and then finallycrashes into a different part of the crater. Just four minutes will separatethe impact of the Centaur upper stage from the impact of LCROSS.
A similarly compressedschedule has defined the mission from the beginning. The LCROSS preliminarydesign review was held in September 2006, just shy of five months from theselection. LCROSS passed its mission confirmation and critical design reviewsin February 2007. Just under a year later, the LCROSS instrument payload, afterbeing assembled and tested at Ames, was shipped to Northrop Grumman's Redondo Beach, Calif., campus for integration with the spacecraft.
Dan Andrews, the LCROSSproject manager at Ames, said one of the keys to keeping to such a tightschedule has been NASA's willingness to let the LCROSS team take more risksthan the agency usually tolerates. LCROSS formally is designated a Class Dmission. Whereas NASA's human missions and multibillion-dollar planetaryflagships are considered Class A missions, Class D missions, Andrews said, "areat the other end of the spectrum. They are very risk tolerant. D is as tolerantas the agency gets."
Andrews said the Class Ddesignation gives LCROSS latitude to do less mission assurance and "lighter,more strategic testing" in order to keep the mission within its cost andschedule box.
To keep overall missionrisk in tow, Andrews said, the LCROSS team has striven to keep the spacecraftdesign as simple as possible and use high heritage hardware wherever it can.
"If you take a lookat our avionics, at our star tracker, at our core sun sensors and all of ourpayload instruments ? these have all either flown spaceflight missions, or are[Defense Department] proven [equipment] in the case of the payloads,"Andrews said. "We've even got some automotive industry industrial devicesthat are being used on this that we have then flight qualified on our own."
Steve Hixson, NorthropGrumman Space Technology's vice president of advanced concepts, in an April 10interview here with Andrews, credited the involvement of young engineers on LCROSSwith the project's success to date.
"They don't have anypreconceived notions as to how long things take," he said. "Theyhaven't been told it cannot be done."
From a work-forcedevelopment point of view, Hixson said, LCROSS is providing a great trainingopportunity for the new generation of engineers the aerospace industry sorelyneeds.
"The neat thingabout these kinds of missions is a young engineer can get the experience of allphases of a program ? the design phase, the fabrication of equipment, theintegration and test ? in two years rather than 10 years," he said. "Forthe Gen Y's and millennials that are entering our industry, they are prettyimpatient in that regard, so these kind of missions are very attractive fromthe point of view of training a work force fairly quickly."
"And a Class Dmission is an excellent training ground for that," Andrews added.
The core of the LCROSSmission is the Evolved Expendable Launch Vehicle Secondary Payload Adapter(ESPA), a rugged aluminum ring roughly 1.5 meters in diameter designed by theU.S. Air Force as a way of fitting up to six tiny satellites into an Atlas 5 orDelta 4 below the rocket's primary payload. The ESPA ring made its debut inMarch 2007, carrying four military microsatellites into orbit beneath thelarger Orbital Express spacecraft.
Hixson said LCROSS marksthe first time that an ESPA ring has been outfitted with a propulsion system,effectively transforming the aluminum ring into a standalone spacecraft.
"So that is veryexciting to us," he said. "It is now Air Force policy that every EELVlaunch will have an ESPA ring and I think their hope is that these sort[s] ofthings will be leveraged as additional launch capability is available."
Northrop Grumman alreadyhas been thinking about how the approach taken with LCROSS could be applied toother mission needs.
"We've looked at allsorts of things," said Dave Ryan, Northrop Grumman Space Technology's vicepresident for civil space programs. Adding additional avionics would give anESPA-based spacecraft the added redundancy it would need to do longer durationmissions, Ryan said, including Earth-observation and planetary treks and "conceivablyeven a similar kind of mission where we might direct a projectile into Mars andfind out more about the crust construction of the planet."
"There's a lot offlexibility using the ESPA ring type of architecture and the attractivenessthat most of these missions could be done in a couple of years. They could berapid response missions and with some of the additional things we've learneddoing LCROSS be even longer lived."
For now, at least, Ames and Northrop are focused on making LCROSS a success.
Hixson said thespacecraft is fully assembled except for its fixed solar array, which is readyto be installed once the spacecraft's performance tests conclude in the weeksahead. After that, LCROSS will undergo a couple months of environmental testsbefore shipping out to Cape Canaveral, Fla., in late July or early August ?several weeks ahead of schedule.
"There were somenaysayers on various sides when we started doing this," Hixson said. "Whetheror not we'd be able to do this quickly was a real question."
Although it appears to bea moot point given that LCROSS is closer to shipping out than the Lunar ReconnaissanceOrbiter (LRO), NASA would have no qualms about leaving LCROSS on the groundif it was not ready to go when LRO lifts off. Nonetheless, Hixson said knowingthat push come to shove NASA would fly ballast in place of LCROSS has helpedkeep the team motivated.
"Thechoice is do you fly this or do you fly a mass simulator ? that drivesdecisions along the way, and it also drives the work force ? both on thegovernment side and on the contractor side ? to team together and sometimesjust out of pride and say, 'Well, they're not going to fly a mass simulatorinstead of us,'" Hixson said. "We've got a very energized, verymotivated work force on both sides."
- Video Player: Incentive to Innovate
- Video Player: Moon 2.0
- Video Player: Moon meets Rover