It’s 7:30 p.m. on Sunday, August 5 in Pasadena, California, and the evening is finally offering some relief after a scorching day. People are beginning to flood the campus of NASA’s Jet Propulsion Laboratory, where in three hours the world will learn the fate of the newest Mars rover, Curiosity.
From This Story
Nearby, where redwood tables and chairs are clustered around a large pool and fountain, JPL scientists and engineers chat in small groups, some talking with reporters. At a glance the scene is casual, even celebratory – like an outdoor cocktail party. A friendly but tense cocktail party.
Tom Rivellini, principal engineer for Entry, Descent and Landing (EDL) systems, is talking with colleagues in front of a large tent showcasing full-scale models of NASA Mars explorers: orbiters Mars Odyssey and Mars Reconnaissance Orbiter; landers Pathfinder, Mars Exploration Rover and Phoenix; and the much larger Curiosity.
Rivellini, like others on the science team, says he feels confident of success. But he also says he is resigned to whatever happens. “There’s nothing we can do at this point,” Rivellini says. “It’s nerve-wracking.”
Ten years of design work, mechanical tests, white board sessions, computer simulations, prototype tests in the desert, and intensive and endless performance reviews – all of this is riding on a spacecraft now speeding toward the Martian atmosphere. If all goes according to plan, Curiosity’s seven-minute descent, culminating in a cable drop from a rocket-powered sky crane, will kick off the most ambitious mission yet in our exploration of Mars.
John Essmiller, a systems engineer for guidance, navigation and control, is focused on how the onboard radar will perform in the final moments of the descent. Determining Curiosity’s altitude and speed relative to the Martian surface will be critical for timing the rocket firings.
“I think for me, getting that solution relative to the ground will be a big relief,” he says.
More than an hour from the scheduled landing, a crowd has gathered outside the newsroom at JPL, and there’s the sound of frequent laughter. Actor Seth Green holds court, cracking jokes. He is one of numerous celebrities invited to JPL, including musician will.i.am, Jeopardy’s Alex Trebek and others. Someone says Mars is now visible in the sky and the International Space Station is passing overhead. The crowd spills outside, and a few people hold their iPads and iPhones up to the sky, star maps glowing in the dark.
The actual landing sequence passes dizzyingly fast. At 10:06 p.m. in California, mission control receives word that Mars Odyssey, pre-positioned in Martian orbit, will be in the right orientation to track Curiosity’s landing as it happens – which had not been guaranteed.
Cruise stage separation occurs at 10:14 p.m. and atmospheric entry at about 10:25. A minute later the craft experiences peak heating and peak deceleration, absorbing 11 to 12 Gs. A quick succession of reports from the control room: chute deployed, 90 meters per second, 6.5 kilometers and descending … Odyssey telemetry still strong … powered flight … 1 kilometer and descending, 70 meters per second …50 meters per second, 500 meters altitude … ready for sky crane … 10 meters per second, 40 meters altitude … sky crane has started … touchdown.