GRAIL mission to launch today

Sep 08, 2011
These images show the various stages of pre-launch preparations of NASA's twin GRAIL spacecraft at Space Launch Complex 17B on Cape Canaveral Air Force Station in Florida. Image Credit: NASA/JPL-Caltech

(PhysOrg.com) -- NASA's GRAIL spacecraft are set to launch to the moon aboard a United Launch Alliance Delta II rocket on Sept. 8, 2011, from Cape Canaveral Air Force Station, Fla. There are two instantaneous (one-second) launch windows at 5:37:06 a.m. and 6:16:12 a.m. PDT (8:37:06 a.m. and 9:16:12 a.m. EDT). The launch period extends through Oct. 19. The launch times occur approximately four minutes earlier each day.

GRAIL's primary science objectives are to determine the structure of the , from crust to core, and to advance understanding of the thermal evolution of the moon.

The lunar orbiters are nestled inside the top of a United Alliance Delta II 7920H-10C , the most powerful Delta rocket in NASA's inventory.

On launch day, Sept. 8, NASA TV commentary coverage of the countdown will begin at 3 a.m. PDT (6 a.m. EDT). The coverage will be webcast at www.nasa.gov/ntv . Live countdown coverage on NASA's launch blog also begins at 3 a.m. PDT (6 a.m. EDT) at www.nasa.gov/mission_pages/gra… unch/grail_blog.html . Coverage features real-time updates of countdown milestones, as well as streaming video clips highlighting launch preparations and liftoff.

The launch will also be online, with a live chat available, on Ustream TV, at www.ustream.tv/nasajpl2 .

Here is a timeline of expected launch milestones:

Launch

At liftoff, the rocket's first-stage engine and six of its nine strap-on motors will ignite, and the rocket will be airborne, carrying GRAIL up and over the Atlantic Ocean.

First six solid rocket motors are jettisoned

GRAIL's Delta II is carrying nine strap-on graphite-epoxy motors. The first six will be ignited at the time of . The remaining three will be ignited shortly after the first six strap-on motors burn out.
Fairing separates

After the Delta's first stage completes its tour of duty, its second stage, which will provide 9,645 pounds of kick for GRAIL, will begin the first of two scheduled burns.

Shortly after ignition of the rocket's second stage, the Delta's 30-foot-long (8.88-meter-long) nose cone, or fairing, will separate and be jettisoned as planned, providing the GRAIL twins with their first taste of exo-atmospheric existence.

Parking at 17,500 miles per hour

The Delta's second stage will temporarily stop firing, as planned, and the rocket and GRAIL will begin a planned coast phase, also known as a "parking orbit" at about 90 miles (nearly 167 kilometers up).

GRAIL heading from Earth to the moon

The Delta's second stage will begin a second burn. This approximately four-and-a-half-minute-long burn will place GRAIL on its desired trajectory to the moon.

Spacecraft begin to separate from second stage

The GRAIL-A spacecraft begins its separation process from the Delta's second stage. The GRAIL-B spacecraft separates about 8 minutes later. At this point, the moon is three-and-a-half months away.

Explore further: NASA craft set to beam home close-ups of Pluto

add to favorites email to friend print save as pdf

Related Stories

GRAIL moon twins are joined to their booster

Aug 18, 2011

(PhysOrg.com) -- NASA's lunar-bound GRAIL twins were mated to their Delta II launch vehicle at the Cape Canaveral Air Force Station's Launch Complex 17 at 8:45 a.m. EDT (5:45 a.m. PDT) today. The 15-mile (25-kilometer) ...

NASA's twin craft arrive in Florida for moon mission

May 24, 2011

(PhysOrg.com) -- NASA's twin lunar probes have arrived in Florida to begin final preparations for a launch in late summer. The two Gravity Recovery And Interior Laboratory spacecraft (Grail) were shipped from ...

GRAIL launch less than one month away

Aug 12, 2011

(PhysOrg.com) -- NASA's twin lunar probes – GRAIL-A and GRAIL-B - completed their final inspections and were weighed one final time at the Astrotech Space Operations facility in Titusville, Fla., on Tuesday. ...

Recommended for you

NASA craft set to beam home close-ups of Pluto

13 hours ago

Nine years after leaving Earth, the New Horizons spacecraft is at last drawing close to Pluto and on Sunday was expected to start shooting photographs of the dwarf planet.

Elon Musk's SpaceX drops lawsuit against Air Force

23 hours ago

A spacecraft company run by billionaire Elon Musk has dropped a lawsuit alleging the U.S. Air Force improperly awarded a contract to launch military satellites to a joint venture between Boeing and Lockheed ...

NASA spacecraft almost to Pluto: Smile for the camera!

Jan 23, 2015

It's showtime for Pluto. NASA's New Horizons spacecraft has traveled 3 billion miles and is nearing the end of its nine-year journey to Pluto. Sunday, it begins photographing the mysterious, unexplored, icy ...

Gullies on Vesta suggest past water-mobilized flows

Jan 23, 2015

(Phys.org)—Protoplanet Vesta, visited by NASA's Dawn spacecraft from 2011 to 2013, was once thought to be completely dry, incapable of retaining water because of the low temperatures and pressures at its ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.