Dwarf planet? Five reasons to care about NASA's Dawn mission to Ceres

On March 6, NASA’s Dawn spacecraft will be pulled into orbit around the dwarf planet Ceres, reaching the peak of a mission that could help us better understand the origin of our solar system. Space buffs are psyched, and non-space-buffs should be too. Here’s why:

1. The photos

Dawn, which launched back in 2007, has finally traveled close to Ceres in last few months. In that time, instruments on the spacecraft snapped pretty amazing pictures of the dwarf planet. This, for example, is what Ceres looked like from Dawn in December:

NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

And this is what Ceres looked like from Dawn in mid-February:

NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Dawn will be the first spacecraft to reach a dwarf planet, so these close-up shots are already making history. And we’ll be seeing more before the mission ends in 2016.

2. Science!

NASA describes the point of the Dawn mission, which also explored the asteroid Vesta in 2012, as “characteriz[ing] the early solar system and the processes that dominated its formation.” An article in the journal Science, “Dawn probe to look for a habitable ocean on Ceres,” notes that the presence of ice on the dwarf planets has “astrobiologists salivating at the arrival of NASA’s Dawn spacecraft.”

Researchers suspect that Ceres is comprised of water, and that it (or a planet like it) may have physically brought water to Earth. Dawn Principal Investigator Christopher Russell explains: “We think that the building blocks of Earth were the siblings of Ceres and Vesta…those like Vesta came to Earth and delivered the iron core, and other materials, while others, like Ceres, brought water.” Getting closer to Ceres will help confirm, or contradict, the hypothesis.

3. A history made for the movies

It took more than seven years for Dawn to reach Ceres, but much longer for the Dawn team to actually get the mission off the ground. Including the earliest iteration, the mission dates back to 1992, Dawn’s Russell told Fusion in a phone interview.

“We designed missions and proposed them, but it was not until the year 2000 that NASA showed interest in developing our concept,” he said. “So we had eight years of repeatedly refining our mission and sending it to NASA for consideration.” They failed to advance to the pitch phase three times before, in 1994, 1996, and 1998.

By 2000, Russell’s team was one of three finalists to present a proposal for a NASA discovery mission. In September 2001, the Dawn team prepared to speak to NASA a day ahead of the formal presentation, but other events took over. “We were going to review our mission with NASA officials and go through everything we were doing, showing how prepared we were,” he said. “We looked up at the TV screen and saw the World Trade Center on fire and we knew that something had gone terribly, terribly wrong.” That meeting was cancelled, and Russell and his team drove rental cars back from Washington, DC, to California.

Eventually, the team was able to present before NASA, and Dawn was selected for a Discovery mission. “Things went well until Christmas Eve 2003, when our project was suddenly canceled,” Russell said. They were reinstated after Orbital Sciences Corporation, the mission’s spacecraft partner, said they’d be willing to continue at cost. But then, in 2005, a changing of the guard at NASA again put the mission in jeopardy. “Every time there’s a change in administration there’s new people at the top,” said Russell. The new officials shut down the project in 2006. “They stopped us doing new work [in 2005] but didn’t fire everybody or close after the congressional hearings were over in June… This time, it was while I was attending my mother’s funeral that I received the news. JPL [NASA’s Jet Propulsion Laboratory] protested and a review of the project was held and we were reinstated again.”

Dawn launches. Image via NASA TV

By 2007, NASA was firmly behind the Dawn mission.

4. The mystery of the spots

Last month, Russell said in a statement that “we expected to be surprised; we did not expect to be this puzzled.” Asked to expand, he said, “I thought that when the surprise came we would understand. You see something and say ‘Aha!’ that’s the answer, but instead we keep getting higher and higher resolution pictures, and those higher resolution pictures are not solving the problem.” That problem is that two bright spots on Ceres are being picked up by Dawn’s instruments. At first, there was only one.

NASA/JPL

But days later, the Dawn team picked up a second, dimmer spot next to the first one discovered.

NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

In a statement released by NASA, Russell said that “Ceres’ bright spot can now be seen to have a companion of lesser brightness, but apparently in the same basin. This may be pointing to a volcano-like origin of the spots, but we will have to wait for better resolution before we can make such geologic interpretations.”

He told Fusion, “We keep trying to unwrap Ceres to get down to what it is that is causing that bright spot, and we just haven’t got there yet. We’re trying to solve the problem of, why does this very dark body have a few very bright spots? There’s a lot of different things that are bright — for example, salt is bright, the material on the surface could be producing salt of different types.”

It’s also possible that those spots are related to plumes of water vapor the European Space Agency’s Herschel telescope discovered last year.

NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

The way to solve the problem of the spots, Russell told Fusion, is through snapping more, higher resolution photos of Ceres, soon. “We’ve been doubling our resolution, getting twice as close — but if we don’t solve it very quickly there’s a period of time coming up in March and April when we move further away before we come back to the higher resolution.” That dark period will be when Dawn is on the planets dark side, so the team needs a few photos within the coming weeks to figure out that spot.

5. A tale of triumph

Russell sees a lesson in the journey. “When you have a good idea, keep after it. Do not give up,” he said.

Danielle Wiener-Bronner is a news reporter.