After Dodging Bullets in Development, MMS Set for Launch
GREENBELT, Md. — NASA’s formation-flying Magnetospheric Multiscale (MMS) mission is at last preparing for launch aboard its Atlas 5 rocket after a bullet-dodging development cycle complicated by a mass of bad parts, a government shutdown and a last-minute replan of final environment testing because of a double-booked cryogenic chamber.
After all that, the $850 million heliophysics observatory will launch March 12, about five months late, and cost roughly 3 percent more than estimated in 2009, when NASA Headquarters approved development.
Led by a team at NASA’s Goddard Space Flight Center here, MMS comprises four virtually identical octagonal spacecraft that will lift off from Cape Canaveral Air Force Station, Florida, to a highly elliptical 28-degree orbit for a two-year primary mission.
During the first year of their mission, the MMS fliers will swing about as close to Earth as 7,500 kilometers and about as far away as 75,000 kilometers. In the second year of operations, MMS will raise the high point of its orbit to almost 160,000 kilometers — about a sixth of the way to the moon.
The observatory will observe and record the physical phenomenon called magnetic field reconnection. This little-understood process involves high-energy interactions between overlapping magnetic fields, such as those of the sun and Earth. Magnetic reconnection, which happens in the blink of an eye and releases tremendous amounts of heat and energy, occurs not only in space, but also on Earth inside nuclear fusion reactors.
The U.S. solar science community anointed the study of magnetic field reconnection as a top priority in a 10-year science roadmap, or decadal survey, published in 2002 by the National Research Council.
Magnetic reconnection is “a process that happens throughout the universe that we don’t understand,” Brent Robertson, deputy program manager for MMS, told SpaceNews in a Feb. 10 interview here. “So understanding it, who knows what that’s going to lead to?”
Magnetic reconnection happens so quickly that “previous spacecraft basically missed it,” said Tom Moore, MMS project scientist. “It goes by in a fraction of a second.”
Getting a good look, one that could record the sort of data scientists would fight for grant money to study, required building a small squadron of spacecraft. Doing that, Robertson said, meant accepting a design that used massive quantities of parts no one had ever tested under the conditions in which MMS will operate.
And as with any untested design, there were problems lurking in the weeds for the MSS team.
The mission was stung particularly by the failure of high-voltage optocouplers, crucial subcomponents of the sensors in the MMS Fast Plasma Instrument suites. Each of the four spacecraft carries one such suite, making for about 300 optocouplers aboard MMS.
Optocouplers transfer electric signals via light waves. The ones in MMS are made by Amptek of Bedford, Massachusetts — which was acquired in November 2014 by Ametek of Berwyn, Pennsylvania — and their failure became apparent only after the MMS team integrated them with the sensors in the Fast Plasma Instrument suites.
The first batch of optocouplers fell apart after repeated exposure to extreme swings in temperature that are common in space. The MMS team replaced the failed optocouplers with new ones, and dedicated some extra spacecraft power to keeping the instruments that house the optocouplers constantly cool.
“We made the mission much more benign for these instruments, both in terms of how long we put high voltage on them and essentially almost keeping them at room temperature for two years so we don’t stress the parts,” said Craig Tooley, MMS program manager. In addition, the Fast Plasma Instrument suites will be switched on only when MMS is nearing the top of its orbit. Conserving power this way will limit the internal heat to which the instruments are subjected, Tooley said.
The Fast Plasma Instrument is being built by the Southwest Research Institute under a $225 million contract awarded in 2004.
In a phone interview Feb. 27, John Pantazis, founder and former chief executive of Amptek, said the parts failed only because Southwest Research Institute (SwRI) was “using the high-voltage optocouplers outside of our specifications.”
“We’ve been making those parts for 25 years and only this particular experiment, MMS, has managed to make them fail,” Pantazis said.
Jim Burch, vice president of SwRI’s space science and engineering division, said Amptek’s stock optocouplers could not meet the Fast Plasma Instrument’s requirements so SwRI asked Amptek to deliver a batch that met a tougher specification.
Pantazis said meeting SwRI’s requirements was no easy task.
“We didn’t even know how to write specifications for the conditions those guys were using them,” Pantazis told SpaceNews.
Sure enough, some of the nonstock optocouplers failed, prompting NASA to initiate the remedy Tooley described.
With the fix in place, Burch said, “we’re 100 percent confident in the parts.”
The optocoupler issue was dire — it could have led to total MMS failure not long after launch — but the replacement and redesigns associated with it were not the only things that led to cost and schedule overruns for the mission.
By the time MMS was ready for its final space environment tests in Goddard’s thermal vacuum chamber, the James Webb Telescope was, too.
Whereas MMS will ring in at about $1 billion to build and operate for its primary mission, James Webb will cost almost $9 billion. Webb’s price tag alone virtually assured that the infrared astrophysics observatory, already in hot water with Congress for the billions of dollars in cost growth it has registered since its confirmation review in 2008, would have priority in the Goddard cryo chamber.
But even if price and politics were not issues, the cryogenic testing regime for Webb, which will fly much closer to the sun than MMS, was the more complicated of the two projects competing for chamber time, Tooley conceded.
“The cost of delaying or moving James Webb was much greater than the impact for moving us,” Tooley said.
So in September 2013, MMS moved its cryogenic vacuum tests 30 kilometers down the road to the Naval Research Laboratory in Washington, forcing the MMS team to embark on essentially the same process required to ship the spacecraft for launch. Shipping costs, coupled with the bill for using the Navy’s test chamber, sucked up about $33 million of the project’s reserves, according to a 2013 report by the Government Accountability Office.
Even this inconvenience might not have been enough to slip MMS’s launch had not the federal government shut down in October 2013, Tooley said.
“As an in-house NASA mission, the impact on us is probably more severe than a contracted mission,” Tooley said. “If the contract’s open and it’s funded, some work can continue to happen even when [the government is] shut down. Goddard almost got shut down lock stock, and we just had to absorb that downtime.”
MMS lost about three weeks to the shutdown, Tooley said. However, launch provider United Launch Alliance, juggling NASA and Defense Department missions, could not simply launch MMS three weeks later than its originally planned October 2014 date. As a result, MMS waited for the next available slot on ULA’s manifest, which happened to be the currently scheduled March 12 date.
MMS is the fifth in NASA’s line of center-managed Solar Terrestrial Probes missions — and it could be the last to be managed that way, if the White House and Congress heed the advice the heliophysics community handed down in its most recent decadal survey, which was published in 2012.
Worried that the U.S. budget will only get tighter, the solar science community urged NASA to take Solar Terrestrial Probes missions out of the hands of centers like Goddard and give management responsibility to a single principle investigator, whose costs would be capped at $500 million.
In its 2016 budget request, NASA said the next Solar Terrestrial Probes mission would launch no sooner than 2023, with solicitations to appear in 2017 or so. The agency requested roughly $400 million for the Solar Terrestrial Probes line between 2017 and 2020, the last year covered in the request. The total assumes the start of a new Solar Terrestrial Probe in 2017, and also continuing operation of MMS and other missions in that line.