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Planetary News: Mars (2006)A New Arrival at Mars: The Mars Reconnaissance Orbiter Earns Its 'O'By A.J.S. RaylMarch 10, 2006
The Mars Reconnaissance Orbiter (MRO) pulled into port at Mars today after a 493-kilometer (306-million mile) journey and, right on schedule, slowed and dropped seamlessly into orbit. “Today we earned our ‘O’ – we are the Mars Reconnaissance Orbiter and we were not until today,” said an obviously happy Howard Eisen, flight systems manager at JPL. MRO, which was designed and developed by the Jet Propulsion Laboratory (JPL) and Lockheed Martin Space Systems as a "next generation" spacecraft, joins three other orbiters -- NASA's Mars Global Surveyor and 2001 Mars Odyssey, and the European Space Agency's Mars Express -- and two American rovers, Spirit and Opportunity, each of which has been exploring and studying the Red Planet for more than 2 years. This new $720 million dollar orbiter brings to the elite flotilla the most technically advanced payload ever sent to another planet, including state-of-the-art suites of scientific, engineering, and communications instruments that give MRO the capability of returning more than 10 times the amount of data returned by all previous Mars missions combined and rewriting the planetary textbooks. MRO initiated main engine burn for Mars orbit insertion (MOI) at 1:24 pm Pacific Standard Time (PST) -- essentially putting the "foot on the brakes" to reduce the spacecraft's velocity by at least 20% as it swung around the Red Planet at 5,000 meters per second (11,000 miles per hour). Orbit insertion is like getting a spacecraft to sail through a keyhole. Since it takes about 12 minutes for a signal to get from Earth to Mars, there was no time in the final minutes leading up and during the burn for the team to react or make any changes, so MRO was on its own. Despite the "tremendous amount of anxiety and concern" team members had been feeling in the days leading up to MOI, as Jim Graf, MRO project manager at JPL put it earlier this week, they had been unusually calm this morning. And, as it turned out, the maneuver turned out to be textbook. The spacecraft was on time and on the money. “We got through that keyhole,” said a beaming Rich Zurek, MRO project scientist at JPL, who has suffered more Mars mission losses than any other scientist. It’s really great to be here right now -- I’ve gotta tell you, it’s great to be on the flip side of M-O-I,” said a jubilant Graf at the post-arrival press conference. “We started out on the 12th of August [2005], with a picture perfect launch and the whole mission is continuing along the same way. Today was picture perfect. In fact I thought today was a simulation because we came so close to being right on.”
In fact, the MOI maneuver “couldn’t have been better,” reported Eisen. Prior to beginning the maneuver, the spacecraft had to be pressurized, a critical task if MRO was to make it safely into Martian orbit. “The pressurization occurred on time and that was the first big cheer you heard from the crowd at 35 minutes before MOI [beginning at 1:24 pm PT], and we had almost instantaneous confirmation that the system pressurized as planned,” he said. At 1:46 pm PST, MRO went behind Mars and out of communication range as scheduled, leaving mission control in the dark for the last 6 minutes of the burn, which engineers designed to slow the spacecraft just enough for Mars' gravity to capture it in to a very elongated elliptical orbit. For the next 30 minutes, the team persevered through the "white-knuckle" period that every space mission knows. “John Glenn gets a lot of credit for sitting on top of a rocket and his pulse didn’t go up above 50 the whole time,” said Jim Crocker, vice-president of the Civil Space division at Lockheed Martin. “I don’t know what the big deal is – the whole time we were behind Mars, my pulse didn’t go above zero.” But when it was over, held breaths, and pulses, turned to big sighs and huge smiles. Right on schedule, at 2:16 pm PST, MRO emerged from behind the planet and contacted Earth. Despite the fact that mission control picked up the signal immediately, the team didn't know for sure if the spacecraft was in orbit or not. In order to make that judgment, engineers had to get and review the Doppler data. As it turned out, it didn't take long. Just about 11 minutes later, at 2:27 pm, the announcement came over the loudspeakers: ‘We have 2-way Doppler and MRO is in orbit around the planet Mars!’ Project Manager Graf whooped and threw his arms into the arm with delight and, no doubt, relief, as the mission control room erupted in a roar of cheers and applause. “We didn’t have to send any commands to the spacecraft at all until after we saw it on the other side of the planet,” Eisen said at the press conference. “We barely dipped into our batteries. Less than 10% came out of the batteries. We saw the spacecraft at 2:16 pm, which is exactly when predicted. The commanded velocity change on the vehicle had been 2,237.6 mph and we overshot that by 0.4 mph,” he noted with a grin. They did notice that during the burn MRO appeared to be “underperforming by about 2%,” but the vehicle is smart enough to take care of itself, Eisen pointed out. “It actually burned 33 seconds longer to make up the difference and that’s why we came in so exact.” At 3:04 pm PST, MRO responded to commands properly. “We got it back to high-rate com [communications] – no errors, no fault protection responses, nothing at all wrong on the vehicle, “Eisen said. “Most importantly, based on the first hour of navigation data, we are in an excellent orbit. We are at 35.5 hours in period – the predicted was 35.4. We are 264.5 miles at closest approach and 28,000 miles tomorrow at farthest all exactly as predicted. So it’s been a wonderful day.” It was all in the fortunes, Eisen confessed. Following a mission-honored tradition, a bunch of the crew got together last night and opened up fortune cookies. From the fortunes received, all indications seemed to point to MRO being a slam-dunk. “My fortune said: A thrilling time is in your immediate future,’” Eisen said, as he pulled the tiny, freshly laminated memento from his pocket. “This is very emotional moment for me,” said Zurek. “Two of our 8 investigations were investigations lost with the Mars Climate Orbiter and are now in orbit at Mars and one of those – Mars Climate Sounder -- was lost also with Mars Observer and so this concludes the recovery of all of the Mars Observer investigations. Now, we’ve got these capabilities at the planet and they way the team and spacecraft have performed say that we have the capability of knocking your socks off when we get these science instruments opened up at the planet.”
With MRO is in orbit, the team will take a much-deserved break, but not for long. “We will be standing down for the weekend to try to give everybody a little bit of rest,” said Graf. “Then, we will start preparing for the aerobraking phase -- those 5 to 7 months when we’ll be slowly reducing the apoapsis – the furthest point from the planet – down from 44,000 kilometers down to about 300 kilometers.” MRO will make more than 500 carefully calculated "dips" into Mars' atmosphere over the next 5 to 7 months in order to gradually shrink the highly elliptical orbit to the nearly circular shape chosen as the most advantageous for the science phase, slated to begin in November. “In preparation for that, what we’ll be doing is performing an operational test to make sure the team is ready to go ahead and start the aerobraking and that all the contingency plans are worked out,” Graf said. “We will also be reconfiguring the spacecraft to make sure that it’s ready to move into that phase.” In addition, they have some software patches they want to upload. “As we’ve been flying, where we see problems or issues or risks we want to mitigate, we’ll develop a software patch to change the basic code. So far, we’ve been able to put up 9 patches and we have a couple more we want to put up.” The plan currently calls for MRO to begin the aerobraking phase at the end of this month. At the same time during the next couple of weeks, the team will be taking some early images with several of the cameras onboard MRO. “Now these are engineering image and not science quality images and are to test out the camera to make sure that they are working properly,” said Graf. “We’ll also be processing that data on the ground to make sure that the processing centers can extract the good images from the data that we’re going to be sending down. So it’s actually be a fairly busy time, just not as intensive as MOI.” Although the science phase does not officially begin until November, there will be some science experiments taking place as MRO is aerobraking. “The first science investigation uses the spacecraft itself as the measuring device, but to do that it has to dip into the atmosphere,” said Zurek. “What we’re doing is we’re working our way down – we’re walking in – to the altitudes that we’ll ultimately be aerobraking at for most of the 5 months. That lowest altitude is only 60 miles above the surface of Mars, so we’re dipping down to altitudes where we’ll be able to understand what the structure of the atmosphere as we go in and out of the atmosphere over 500 orbits over the next 5 months. So that investigation starts with the walk in which will be at the end of March.” Although the NASA Administrator didn’t show up for the event, nor did any of the celebrities or politicos that turned up two years ago for the Mars Exploration Rovers (MER) landings, the joy of victory was every bit as much in the air at JPL tonight and the team was every bit as ecstatic as the MER team was on those two cold and blustery January nights in 2004 – and deservedly so considering that it is technically more difficult to get a spacecraft into orbit than it is to get one on the ground at Mars. “This kind of thing doesn’t happen just by itself,” Graf said in closing. “It happens because we have a dedicated team that works long hours and overcomes a lot of obstacles to get to this point.” That team, he added, also gets a lot of help. “The NOAA [National Oceanic and Atmospheric Administration] space weather forecast team gave us forecasts about the Sun and its activity and the Deep Space Network (DSN) – no mission leaves Earth without them -- maintained lock with MRO all along and were able to recover the spacecraft almost instantaneously after it came out of occultation. The NASA management team suffered with us the whole time all the trials and tribulations and Lockheed Martin did a wonderful job in putting together a great spacecraft, getting it launched, and getting it to Mars.” At the end of this day, NASA got, in every positive sense of the word, what it paid for, said Dan McCleese, the Mars chief scientist at JPL, and the principal investigator of the Mars Climate Sounder, a weather satellite and one of the six science instruments onboard MRO. As space explorers go, McCleese knows well the anguish of missions lost, but today was a new day. This was, after all, the third time he’d gotten a chance to get his weather satellite to Mars – and now with MRO, it was, at long last there, safe and sound. “And it feels great!" he exclaimed. The lesson learned from past failures, said McCleese, is that doing missions on the cheap doesn't work. "With Mars Observer and Mars Climate Orbiter -- the two examples where we failed -- we tried to do it as cheaply as we could; therefore the people standing behind the people who are watching the people doing the work weren't there. Here we had checks and rechecks, redundant systems, testing that we had not done previously, and we were in the hands of very capable people. As for the future exploration of the planet, in my view, it pays to spend the time and money to do it right." After it was all over, the team regrouped at a local area Mexican restaurant to celebrate. As Graf, Eisen, and other team leaders made their entrances they were greeted by standing ovations and margaritas, and the team finally got the chance to breathe out and party down. “It’s been a good day,” said Zurek softly as he headed into the celebration. |
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