A long wait for cosmic answers

Seven years.

By any means, it is a long stretch of time. For a number of scientists in Tucson, however, it is the time they must wait to finish a space project.

The project will make history, by bringing a bit of asteroid dust back to Earth.

Osiris Rex has a mission. Launched in September, the spacecraft will travel to the asteroid Bennu, and then return.

"The Osiris Rex launch was flawless. It was a beautiful launch," said Heather Enos. Now, she and other scientists who planned the mission will be in for a long wait.

First, the spacecraft will slingshot around the earth in a bit less than 342 days, 23 hours, and 13 minutes, for an Earth Gravity Assist.

"We will use a little bit of the momentum and power of the Earth to give us a slingshot, and get us into the path of Bennu and into the orbital plane," said Enos.

Two years later, Osiris Rex will rendezvous will Bennu.

"We arrive at Bennu, and that's the big 'wahoo' moment in the summer of 2018," said Enos.

Bennu is a space rock about 1,600 feet wide, and it is a little taller than the Empire State Building. It may, in the 22nd Century, hit Earth, although the chance is one in 2,700.

"We will spend two years mapping the surface," said Enos. During the mapping, Osiris Rex will find the best spot for a final approach, which is targeted for July 4, 2020. The spacecraft is planned to fly so close to the asteroid, that it will be able to vacuum up a two ounce sample of dust. That's about teh same as four tablespoons of sugar.

"We'll then stow the sample in our sample return capsule," said Enos. "We arrive back in the Utah Desert in September of 2023."

In the meantime, the scientists will make sure Osiris Rex stays on course, and the navigation team is using images of stars to make sure Osiris Rex is in the right place. In addition, the team will make sure instruments on Osiris Rex will still work.

More crews will arrive when the spacecraft scoops up the dust on Bennu, and then make its return. It's a long wait, but Enos believes it is worth it.

"You have to remind yourself that the primary goal is to return that sample here, because it's really going to be the gift that keeps on giving for generations to come," said Enos.