|Mission Control: Who's at the Helm?
On Saturday night, January 3, the Mission Support Area (otherwise known as "mission control") at the Jet Propulsion Laboratory will be filled, with every seat at every station occupied by members of the Mars Exploration Rover team. Everyone will be holding a collective breath in anticipation of a safe landing. That's especially true since many describe the challenges of entry into the martian atmosphere, rapid descent, and landing on the surface as "six minutes of terror." [See Video]
For six minutes of entry, decent, and landing, during which it must reduce its speed from 12,000 miles per hour to almost zero, Spirit is on its own. The hard work of scientists and engineers over more than three years has led up to this nail-biting moment. Like coaches watching a star athlete perform, they must let go and wait as the lander does what it was born to do: deposit the rover named Spirit safely on the surface of Mars.
As Mark Adler, Cruise Mission Manager for Spirit, puts it, "In the last hour or two of our approach to Mars, all of us are essentially spectators. By then, we have done all we can to assure a safe landing. We will be very careful spectators though, monitoring all of the data and signals coming from the spacecraft to determine how it is performing. " Mark will be managing the operations team. His job is to approve the final commands sent to the spacecraft and to monitor the progress of events.
Mark is joined by Rob Manning, the Mission Manager for Entry, Descent, and Landing, who must make sure that all of the pieces fall together. From flight software to communications with the Deep Space Network, he oversees every aspect of entry, descent, and landing. Rob agrees that entry, descent, and landing is primarily about monitoring Spirit's progress. "My team worked intensively to develop the dance that unfolds on Saturday night, but now I just watch from the sidelines. I will be carefully listening to the activities of the various teams to make sure that everyone is working together and doing their jobs."
As team member Arthur Amador puts it so well, "This mission is all about people--10% technology and 90% human skill, determination, and spirit. When Spirit and Opportunity land on Mars, we're all going to land with them, because in addition to the circuits and motors and heaters, these vehicles carry us--our hearts, our souls and our dreams." Here's what the rest of the team will be doing.
Jim Donaldson is the Avionics Systems Lead, and will spend a tense six minutes watching events unfold. "It's important to me--I worked on the team that designed many of the electronic boxes that control events during entry, descent, and landing. Afterwards, I'll be part of the team that analyzes the results of the landing. Everything counts."
Attitude Control Systems Team
Fred Serricchio, Steve Collins, and Miguel SanMartin are part of the Attitude Control Systems Team that is responsible for keeping the spacecraft pointed in the correct direction during cruise and for adjusting the spacecraft's course as it approaches Mars. They will monitor the final turn that the spacecraft makes before entry into the martian atmosphere, and will conduct the last check before entry into the martian atmosphere. They will also determine which way is north once the rovers are on the surface. "If all goes well," says Serricchio, "I will be extremely pleased. Ecstatic would probably be a better description."
Entry, Descent, and Landing Activity Leads
Activity Leads Martin Greco and Rob Grover will be monitoring the overall health of the spacecraft as it hurtles toward the martian surface. They will pay attention to how all of the individual system are working together and will pass this information on to the rest of the team. Greco expects he will be calm at first. "There's not much we can do at this point," he says. "A big part of getting the spacecraft to Mars is done, and there's some relief in that, but I'm sure I'll be less calm and more excited as soon as the realization of what we are attempting sinks in."
Fault Protection Team
Tracy Neilson heads up the rovers' fault protection team. This team designed and will monitor the rovers' autonomous software that can detect problems and react to those problems without commands from humans. During entry, descent, and landing, Tracy will monitor the fault-protection data and make sure everything looks normal.
Flight Directors for Spirit
As the Cruise Flight Director, George Chen has been hugely successful in getting Spirit to where it is right now. Over the last six months, Chen has worked with the activity leads and subsystem engineers to ensure the safe operation of the vehicle. In case of spacecraft emergencies, he is responsible for taking the necessary actions to maintain the health and safety of the spacecraft. Entry into the martian atmosphere means a change for Chen as he has successfully completed his stage of the mission and will now pass the baton to Jason Willis, Flight Director for Entry, Descent, and Landing. Jason's job is to get the spacecraft over the finish line and it is his voice that will often break the hush in mission control with spacecraft updates during the fateful six minutes.
Flight Director/Systems Lead for Opportunity
While Spirit's landing will take center stage on January 3, Opportunity will be hurtling toward Mars on the heels of Spirit. Engineers Leo Bister and Scott Doudrick will be monitoring Opportunity's health just like they would any other day. They will also lend additional pairs of eyes on the Spirit data. "If everything is stable on Opportunity, our primary role during Spirit's entry, descent, and landing will be to assess health, flag problems, and support the team however we can," Leo explains.
Flight Software Team
Flight software team mates Kim Gostelow, Ed Gamble, and Glenn Reeves will be watching their program run with the sole purpose of identifying and reporting anything out-of-the ordinary and also applying what's learned to Opportunity. "Of course I will be nervous," says Kim. "Being so close to the design and implementation of the spacecraft, you know all of the thousands of things that have to go exactly right. We're also very aware of the dangers of the martian environment. I am hopeful that it's a nice day on Mars."
Integrated Sequence Team
Arthur Amador, Grace Tan-Wang, Bill Bensler, and Saina Ghandchi are responsible for planning and sequencing the commands that are sent to the spacecraft during cruise and on the surface. They will observe incoming data and verify that the spacecraft is behaving as predicted. In the unlikely event that any last minute unplanned commanding is required, they are responsible for generating those commands.
Don Nieraeth is part of the power subsystems engineering team led by Richard Ewell. Together, they will monitor critical power-related data through entry, descent, and landing and a few hours before. They will report on the power status of the cruise solar arrays and the rover and lander batteries. The lander batteries are of particular importance because they are the main power source during entry, descent, and landing. This phase is the first time in the mission they will be used. "This very exciting day is the culmination of an intense and stressful development, fabrication, test, and delivery process." Ewell remarks. "We've spent the last few years developing one of the most complex power systems that JPL has ever built." Nieraeth calls landing day the "ultimate pay-off," but admits he'll be a little nervous. "The moments leading up to landing will be exciting, but also extremely tense for me since so many different actions during entry, descent, and landing will have to operate correctly and on time for a safe landing on Mars."
Julie Townsend and Ed Swenka will have a lot to do during the hours before entry, descent, and landing. Swenka will be monitoring the results of various systems tests that check the health of the spacecraft prior to entry into the martian atmosphere. Both will be excited, but Julie adds that it will also be a time of apprehension. "So much hard work has gone into the Spirit spacecraft over the past three-and-a-half years, and all of our hopes for more long, fruitful hours of surface operations can be made or broken in those six minutes."
Polly Estabrook, Jim Taylor, and Peter Ilott monitor the tones and other communications that the spacecraft sends back to earth to indicate when various steps in entry, descent, and landing have been completed. They share the information with the rest of the team so that everyone can follow Spirit's fast and furious descent to the martian surface.
As part of the spacecraft's Thermal Team, Glenn Tsuyuki and Eric Sunada monitor the spacecraft's temperature. During the frigid cruise through space to Mars, gas generators and the lander's primary batteries were stored at much cooler temperatures than required for entry, descent, and landing. Tsuyuki and Sunada will verify that the "pre-heating" of this cold hardware is occurring as planned. They will also monitor the rest of the flight system to ensure all temperatures remain within specified limits. Spirit's successful landing on Mars will represent more than a technological achievement to Glenn Tsuyuki, who lost his father to a 14-month battle with cancer as well as fellow development team member Kamesh Mantha. "When we successfully land on Mars, I plan on a moment of remembrance as a tribute to my dad and Kamesh."