NASA's Air Traffic Controller
Belinda Arroyo is in charge of the team that negotiates
tracking time with the Deep Space Network for 12 NASA missions.
May 10, 2002 -
So many spacecraft - so little time - tracking time, that is. It's
something of a luxury these days because of the dozens of space
missions sprinkled around the solar system routinely competing for
the undivided attention of the few antennas capable of communicating
with their spacecraft.
Negotiating tracking time is what Belinda Arroyo's team does for a
living. She is the team chief of the Mission Management Office
Multi-Mission DSN Allocation and Planning Team, an organization that
makes sure that the 12 NASA missions
for which they are responsible
have adequate time allotted with the
Deep Space Network. Managed by NASA's Jet Propulsion Laboratory, the
Deep Space Network
has three sites disseminated in key areas of the world -- Spain,
Australia and California. To communicate with spacecraft, each site
has a 70-meter (230-foot) in diameter antenna and a variety of
Arroyo is so good at what she does that she is even attributed
special powers by those JPL team members who depend on her skills to
communicate with their spacecraft roaming the solar system.
"The Deep Space Network is usually over-subscribed by the many users,
but with Belinda I don't worry about controlling our spacecraft and
retrieving data," said Robert Ryan, Stardust mission flight director.
"Belinda is our 'superwoman.' She makes a very complex negotiation
process seem simple."
Longer missions and a drastic increase in the number of spacecraft
needing the antennas's exclusive attention render scheduling which
antenna to point to which spacecraft a daunting job. The Deep Space
Network currently supports an average of 28 missions per month.
Priority is given to spacecraft performing critical maneuvers such as
orbit insertion or encounters with celestial bodies, but even during
periods of low activities, demand for the antennas is always high
because of limited ground resources.
A comprehensive study finished in February 2001 concluded that new
antennas were needed to meet the growing demand on the network in the
near future. However, NASA approved only one antenna. It is being
built in the network's site near Madrid, Spain, leaving missions
still scrambling for more access.
Arroyo's office is remarkably simple compared to the complicated
schedules she supervises. Plants and flowers lay on top of a file
cabinet, a few pictures adorn the walls. The whiteboard on the wall,
however, tells a different story. Held by magnetic clips, loads of
papers with schedules for each mission cover the writing underneath.
And while often stressful, she says her job is very stimulating.
"It's very exciting to be part of a flight project," Arroyo says. "I
really like learning about each mission, interfacing with the
different people in the missions and working with my team."
The fast pace does take its toll, though.
"It is constant activity. There are no peaks and valleys," she says
smiling. "We are kind of always at a peak because we have a large
number of missions. It can be stressful."
In addition to supporting 12 missions that are currently active,
Arroyo's team is working on another 16 that are still in the
On average it takes about five minutes to lock on the signal from a
spacecraft. To download information, however, can take up to many
hours. The exact time depends on the data rate of transmission and
the kind of information being received by the antennas. Images and
other science data take the longest, while the so-called, "spacecraft
health information" -- used by scientists and engineers to routinely
monitor instruments functionality -- take the least time to download.
Scheduling problems occur because often the ideal view from Earth is
shared by more than one spacecraft. And even a well-coordinated
schedule is useless if an anomaly occurs, leaving Arroyo and her team
of seven scrambling and negotiating, in real time, for additional
time with other users.
"It doesn't happen often but, depending on the anomaly, it can be a
real nightmare," she says. "But even without anomalies, sometimes it
is difficult having to make trades and balance the workload."
Balancing loads, however, is something Arroyo does all week long.
Besides working full time she is also completing a bachelor's degree
in management and human resources at California State Polytechnic,
Pomona. In her spare time, Arroyo does volunteer work with senior
citizens, often in convalescent homes, and in community events. She
also likes to read and when it's time to regenerate her seemingly
inexhaustible energies, she enjoys camping and hiking.
At JPL, Arroyo began as a scheduling engineer in 1991 -- where she
helped develop scheduling software for daily operations that
increased productivity by approximately 50 percent.
Her talent and hard work didn't go unnoticed. In 1999, Arroyo was
awarded NASA's Exceptional Service Medal. Last year, she moved to her
current position as mission management office team chief, where
beside marketing and negotiating services for flight projects, she
develops and manages team processes.
Arroyo also trains new personnel.
"It's a lot of fun to train people and teach them your area of
expertise and watch them grow," she says. "This area introduces you
to a lot of different areas because you work not only with teams --
like the ground data system team or the sequencing team -- but you
work across organizations like navigation and mission planning," she
explains. "I think working in the mission management office is a good
base for somebody coming in new to a flight project. It gives you a
kind of a global view of a flight project and introduces you to
options to help you decide where you might want to go next with your
Next year is looking up as the busiest time ever for the Deep Space
Network. Red planet-bound NASA and European missions are scheduled to
launch, and they will join the spacecraft already there, Mars Odyssey
and the Mars Global Surveyor. These spacecraft, as well as all the
other missions already in space, will need to communicate with Earth
with the same scarce resources.
One at a time, Arroyo and her team will find a way to schedule
tracking time for all of the ones in their mission set.