UPDATE: Story first
posted 7:15 a.m.
There has been a scientific
and public backlash at the thought of shutting down spacecraft, like the
vintage Voyager missions, all for the want of a few millions dollars.
But Voyager is likely to be an
early signal from a growing dilemma of finding cash to keep NASA spacecraft
functioning beyond their initial work period.
There are plenty of
examples, like the still-going strong Mars Exploration Rovers. Also count on
keeping the Hubble Space Telescope alive. Toss in an extended Cassini mission at Saturn too. Also, there's early talk
about the Deep Impact flyby spacecraft possibly using its telescopic gear to
scout about after it completes its main choir of hurling an impactor
at comet Tempel 1 and monitoring the upshot this
coming July.
But now there is growing
talk of setting up something analogous to a "hit squad" at NASA that
impartially agrees what projects should be ended, when, and under what rules.
Reportedly, a number of
space probes could be on the chopping block, from the Ulysses mission to the
Sun to several Earth-oriented space physics satellites busily sleuthing about.
Upsetting to many scientists
is shutting down the long-distance Voyager -- seemingly a fit of heliospheric heresy. The valiant twin Voyager spacecraft
were launched in 1977 and can define the end of the heliosphere
-- the entire region of space affected by the Sun -- and the start of
interstellar space.
The mission currently
employs the equivalent of about 10 full-time people at the Jet Propulsion
Laboratory, significantly less than the approximately 300 during the height of
its legendary "Grand Tour" of the planets through 1989.
Scientific novelty
New NASA Administrator, Mike
Griffin, will likely revisit a number of "pulling the plug"
decisions, suggested Stamatios Krimigis,
Head Emeritus of the Space Department at the Johns Hopkins University Applied
Physics Laboratory in Laurel,
Maryland.
"It's clear that in a
limited resource environment, decisions and choices have to be made...none would
argue with that," Krimigis said. "The key
issue is the criteria used to arrive at such decisions."
Speaking at the press
conference Monday following his appointment, Griffin said NASA was months away deciding
which missions get terminated, and that it "would not be done without a full
and careful review."
But, he added, that is not
"to say that all missions are of the same importance. Voyager may well outrank
others whose time to be turned off really has come. So I'm not making a blanket
offer that we're going to reach a particular answer on any one mission or that
we will treat them all as a block. But we are going to consider it carefully
before we turn anything off."
Principal among the criteria
would be the scientific productivity of a particular mission, Krimigis said.
"This is the area where
the Voyager decision is totally indefensible. Why? Because Voyager has been at
the fringes of the solar 'cocoon' that separates us from interstellar space for
nearly three years now," Krimigis explained.
Voyager has generated impressive science for so many years, and the excitement
hasn't stopped, he observed.
As a principal investigator
on Voyagers 1 and 2, Krimigis also serves in that
role on the Cassini mission now orbiting Saturn.
The scientific novelty of
this region of space is clearly intriguing not only for scientists but the
public at large, Krimigis argued.
Exploration at its finest
Voyager is "exploration
at its finest," Krimigis said. "NASA has no
present plans for an Interstellar Probe, and even if they approved such a
mission tomorrow it couldn't launch until 2014 and wouldn't catch up with
Voyager for at least 15 years after that," Krimigis
noted. Voyager is likely to run low on power by about 2020, he said, but could
possibly continue in some reduced capacity for several years after that, doing
so through power sharing and other procedures.
"It's a legacy mission
that this generation can preserve for our children and even
grandchildren," Krimigis stated. NASA pondering a
pull-the-plug dictum on Voyager, he continued, is a decision without thought
about the mission's current scientific productivity or appeal of the science to
the public.
"After all, $4 million
is $4 million...and to accountants all funds are the same. No wonder the
scientific community has so little confidence in the decision-making at [NASA]
Headquarters," Krimigis said.
Of course, not all extended
missions hold the excitement of the Voyagers, but all of the ones scheduled for
termination next year are scientifically productive, Krimigis
said.
"I believe the return
on investment for all is very high," he said, and there is no way NASA
could reconstitute these assets in the next 20 years. They are the equivalent
of a "Great Observatory" and must be recognized as such, Krimigis concluded.
NASA's extended family
NASA has several spacecraft
they embrace as part of their "extended family".
Mars has become home to the
extended orbital missions of Mars Global Surveyor and Mars Odyssey.
Furthermore, those workaholic surface robots, Spirit and Opportunity,
just got the go-ahead for up to 18 more months of operations - purportedly at
roughly $3 million per month.
The peppy twin Mars rovers
have been a surprise to engineers and scientists. They had already completed 11
months of extensions on top of their successful three-month prime missions. And
what does another 18 months buy?
Pose that question to Steve Squyres of Cornell
University as leader of
the Mars rover science team. He's quick to answer about the value of their
recently renewed Mars driving license.
"The thing that makes
it so valuable is that we keep moving across the Martian countryside. If you're
stuck in one place, sooner or later your science becomes nothing but routine
monitoring of time-varying phenomena... like studying the atmosphere. That's
important science, but it wouldn't use the rovers to anything like their full
capability," Squyres told SPACE.com.
By keeping the rovers on the
move, new places are always just around the bend, beyond a crater wall, or
behind a sand dune.
"One thing that we've
learned consistently on this mission is that our landing sites are so complex
and interesting that when we go to a new place...we see new science," Squyres confirmed.
The surface of Mars is a big
place. It takes a little driving around to find things, said David DesMarais of NASA's Ames Research
Center. He is lead
scientist of the long-term planning team in NASA's Mars Exploration Rover (MER)
mission.
"The longer the mission
goes, the smarter we get about Mars geology," DesMarais
said. "The longer we live...we're doing a better job."
Searching for nickels everywhere
Long-lived spacecraft that
receive mission extensions usually cost less to operate than during their prime
time.
However, they should be made
to run cheaper too, which is not always the case, said Wesley Huntress, Jr.,
Director of the Geophysical Laboratory at the Carnegie Institution of
Washington in Washington, D.C. In a former post, he served as the
chief of NASA's space science missions.
Space is populated with a
large collection of older spacecraft still cranking out data, Huntress said.
That being the case, the accumulative cost of running them begins to become
significant, he said.
And that's what is happening
now, with NASA "searching for nickels everywhere," Huntress stated.
Budget pressure is omnipresent.
"It's a limited
resource. You want to do new things, but you have some old things that are
still productive. How do you make that tradeoff? The advocates of these
missions don't have to worry about that...the folks who are writing the checks
do," Huntress advised. "And so you see that battle happening."
Precipitous decisions
Huntress said he worries
that NASA at its upper levels has lost the understanding that they have
stakeholders. "They can't make precipitous decisions without consultation
with their stakeholders. The idea of canceling Voyager, for example, seems ill
conceived ...it seems to me to make very little sense," he said.
Similar in view is Sean
Solomon, Director Department of Terrestrial Magnetism at the Carnegie
Institution of Washington. He is principal investigator for the now en route MErcury Surface, Space ENvironment,
GEochemistry, and Ranging (MESSENGER) mission.
"One of the reasons
that the Voyager discussion is so intense is because there is a potential for
new science...even though this mission has been on the books now for more than 30
years," Solomon remarked. While NASA has many demands on its resources,
the price tag to follow Voyager a little longer is not that great.
"On the other hand,
there are many missions that are contemplating extended periods. So you
probably can't do them all," Solomon pointed out. "The question is
how do you decide which are the most worthy of these missions to continue to
invest in?"
There are gauges for making
such a determination: Health of the spacecraft's instruments; remaining fuel
onboard to maintain attitude and pointing accuracy; and the originality and importance
of the scientific return.
"But at some point NASA
is deciding between extending a mission and flying a new mission. And that's a
tougher call," Solomon said. "There is a natural tendency for active
scientific groups to continue to want to see data coming in. So that's why any
process of deciding on how to invest scarce dollars in extended missions should
be an objective one...one in which a broader community is looking at comparisons
among different kinds of missions with different kinds of objectives," he
concluded.
Report card: far from stellar
The debate over the Hubble
Space Telescope's longevity is a hard call, Huntress said. Essentially, both
the Hubble and its follow-on, the James Webb Space Telescope (JWST) are on more or less a fixed budget.
"So the money spent on
Hubble you're not going to spend on JWST. When do you make that call? That's a
tough judgment," Huntress said. "And it's tougher in the case of
Hubble because it is not just a telescope for scientists anymore. It has become
the people's telescope."
Try turning off one of the
Mars rovers today, Huntress said. "You'd get the same reaction that you're
getting from Hubble. So I don't think it's peculiar to Hubble. I think it's
peculiar to the way the American public takes ownership of these
instruments," he noted.
During his tenure at NASA,
Huntress had to put to rest the Compton Gamma Ray Observatory. Compton was safely deorbited
and reentered the Earth's atmosphere on June 4, 2000.
"That one had no public
consequences. That was strictly an engineering and scientific decision,"
he said, with gamma ray astronomers knowing that American and European
follow-on missions were coming. "Compton's
time had come."
Overall, NASA's report card
on turning off spacecraft is far from stellar, Huntress admitted. "I think
NASA prepares poorly, if at all, for extended missions...and that includes my
tenure there too. We did not plan well for extended missions because we never
anticipated them. But we always knew there was the potential for them," he
said.
Striking the right balance
"It's something I'm
wrestling with," said NASA's Alphonso Diaz,
NASA's Associate Administrator for the Science Mission Directorate.
"Somebody's extended mission is another person's prime mission," he
told SPACE.com.
Diaz said that a senior
review process done a few years ago to rank the strategic importance of
missions "may or may not be relevant to the discussion today." NASA
is presently engaged in strategic road-mapping, he said, with some missions
perhaps having more significance now given the space agency's Moon, Mars, and
beyond visionary agenda.
"I'm willing to
listen...to sit down and talk about that," Diaz said. "We're currently
developing a strategy to try and understand how to get to another review, one
that's based on more current understanding of the significance of those
missions," he said.
Reducing the cost of
operating some spacecraft over a long period is on the table too, Diaz
explained. Coming up with the right balance of continuing to operate extended missions
versus new developments is the trade that has to be made, he said.
"It'll be a while
before we have a solution," Diaz added. "We can't operate everything
all the time forever."
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