Spaceflight Now Home



The Mission




Rocket: Delta 2 (7920-H)
Payload: GRAIL
Date: Sept. 10, 2011
Times: 8:29:45 a.m. and 9:08:52 a.m. EDT
Site: SLC-17B, Cape Canaveral, Florida

Mission Status Center

GRAIL preview story

High-definition video

GRAIL video archive

Launch window chart

Ascent events timeline

Ground track map

Delta 2 rocket info

Launch Complex 17

The pre-launch flow

NASA press kit

GRAIL fact sheet

Launch handout

Lockheed brochure

Our Delta archive






Mission Reports




For 12 years, Spaceflight Now has been providing unrivaled coverage of U.S. space launches. Comprehensive reports and voluminous amounts of video are available in our archives.
Space Shuttle
Atlas | Delta | Pegasus
Minotaur | Taurus | Falcon
Titan



NewsAlert



Sign up for our NewsAlert service and have the latest space news e-mailed direct to your desktop.

Enter your e-mail address:

Privacy note: your e-mail address will not be used for any other purpose.



Advertisement






Space Books






Lunar tandem successfully enters orbit around the Moon
BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: January 1, 2012


Bookmark and Share

Ringing in the new year with back-to-back successes, a second NASA science satellite slipped into orbit around the moon Sunday, one day after an identical spacecraft braked into the same polar orbit for a $496 million mission to map the moon's interior by precisely measuring how its gravity affects the trajectories of the twin spacecraft.


An artist's concept of the GRAIL spacecraft braking into orbit. Credit: NASA
 
Following programmed instructions, the second Gravity Recovery and Interior Laboratory -- GRAIL -- satellite fired its braking rocket at 5:05 p.m. EST (GMT-5), kicking off a 38.7-minute "burn" to slow the craft enough to let the moon's gravity capture it into an 11.5-hour orbit around the moon's poles.

"Cheers in JPL mission control as everything is looking good for GRAIL-B," NASA said in a Twitter posting after the rocket firing. "It's going to be a great 2012!!"

(LIVE Mission Status Center coverage of the burns)

The identical GRAIL-A satellite arrived New Year's Eve. Over the next two months, both satellites will be maneuvered into circular 34-mile-high orbits before beginning three months of close-order formation flying to map the moon's gravitational field.

By precisely measuring the distance between the two spacecraft as they fly along -- and thus the subtle effects of the moon's gravity as they sail over visible and sub-surface geologic structures -- scientists will be able to determine the nature of the moon's enigmatic core and perhaps confirm or refute theories about how the moon formed at the dawn of the solar system.

"GRAIL's a journey to the center of the moon," Maria Zuber, the principle investigator, told reporters last week. "It'll use exceedingly precise measurements of gravity to reveal what the inside of the moon is like. And that information will be combined with the plethora of other remarkable observations of the moon that have been taken by satellites before and that are being taken right now (to) enable us to reconstruct the moon's early evolution."

Despite more than 100 missions to the moon, including six manned landings, Zuber said more is known about Mars than Earth's nearest neighbor. Major questions, she said before launch, include "is there a core? How did the core form? How did the interior convect? What are the impact basins on the near-side flooded with magma and give us this man-in-the-moon shape whereas the back side of the moon doesn't have any of this?"

"These are all mysteries that despite the fact we've studied the moon before, we don't understand how that has happened. GRAIL is a mission that is going to tell us that."

Along the way, it also may help inspire school kids to take more of an interest in science. Each satellite is equipped with four cameras sponsored by former shuttle astronaut Sally Ride's science education company that can be used by students around the world to photograph the lunar surface. Zuber said more than 2,100 schools had signed up to participate in the "Moonkam" program.

"Students, in collaboration with their teachers, will be able to look at where the trajectory of the two spacecraft are and then when the school's turn comes up they will be able to target images and then take their own images of the moon," Zuber said. "We've had a great response to the Moonkam project, we're still accepting applications. We can accommodate another several hundred schools into the program if there's interest in doing that."


An artist's concept depicts the GRAIL spacecraft conducting their mapping mission and relaying the data to Earth. Credit: NASA
 
The twin GRAIL spacecraft were launched from the Cape Canaveral Air Force Station in Florida on Sept. 10 atop a United Launch Alliance Delta 2 rocket. While a larger rocket could have boosted the satellites to their target in a matter of days, the less powerful Delta 2 kept costs down and gave flight controllers more time to activate, check out and calibrate the sensitive radio gear that will be used to precisely measure the distance between the spacecraft.

The so-called low-energy trajectory was set up to allow about a day between the arrival of GRAIL-A and GRAIL-B. Following programmed instructions, GRAIL-A's main engine fired at 4:21 p.m. Saturday, burning for nearly 40 minutes to slow the craft by some 427 mph and put it into the planned 11.5-hour elliptical orbit.

"Just because we're in lunar orbit doesn't mean we're good to go for the science phase," David Lehman, GRAIL project manager at NASA's Jet Propulsion Laboratory in Pasadena, Calif., said last week. "There's still work to be done. Following lunar orbit insertion, the spacecraft will perform a series of intricate burns that take about two months. These are required before we can get both spacecraft down to a 34-mile altitude. Once that's done, that's when the science for GRAIL can begin."

If all goes well, science operations will begin around March 8. Flying in formation at distances ranging from about 46 to 140 miles, the two spacecraft will send radio pulses and timing signals back and forth to precisely measure the distance between them.

Sailing over buried mass concentrations, craters, mountain ranges, basins and other geologic features, the satellites will ever so slightly speed up and slow down, one after the other. The ranging system is accurate enough to detect differences of as little as one micron, or the width of a red blood cell.

By carefully analyzing those changes, scientists can determine the distribution of mass within the moon to gain insights into its hidden interior structure and the nature of its deep interior.

The primary mission must be completed by early June when the solar-powered satellites will experience an extended eclipse. The spacecraft were not designed to survive that long without power, but Zuber said the systems are performing better than expected and it now appears an additional, extended mapping mission may be possible.

Spaceflight Now Plus
Additional coverage for subscribers:
VIDEO: THE FULL LAUNCH EXPERIENCE PLAY
VIDEO: ONBOARD ROCKET CAMERA: GRAIL-A DEPLOYED PLAY
VIDEO: ONBOARD ROCKET CAMERA: GRAIL-B DEPLOYED PLAY
VIDEO: POST-LAUNCH NEWS CONFERENCE PLAY

VIDEO: GRAIL LAUNCH AS SEEN LIVE! PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: PAD 17A CAMERA PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: PAD 17B CAMERA PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: BACKSIDE CAMERA PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: NORTHSIDE CAMERA PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: JETTY PARK PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: PATRICK AFB PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: PRESS SITE 1 PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: KSC TRACKER PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: TRIDENT BLUFF PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: UCS 23 TRACKER PLAY | HI-DEF
VIDEO: AERIAL VIEWS OF HISTORIC COMPLEX 17 PLAY | HI-DEF

VIDEO: FIRST LAUNCH ATTEMPT IS SCRUBBED PLAY | HI-DEF
VIDEO: MOBILE SERVICE GANTRY ROLLED BACK PLAY | HI-DEF
VIDEO: TIME-LAPSE OF TOWER RETRACTION PLAY | HI-DEF

VIDEO: GRAIL'S PRE-LAUNCH CAMPAIGN PLAY | HI-DEF
VIDEO: ROCKET'S PRE-LAUNCH CAMPAIGN PLAY | HI-DEF
VIDEO: GRAIL PRINCIPAL INVESTIGATOR INTERVIEW PLAY | HI-DEF
VIDEO: PREVIEW OF DELTA 2-HEAVY ROCKET'S ASCENT PLAY | HI-DEF

VIDEO: LEARN ABOUT GRAIL'S SCIENCE GOALS PLAY
VIDEO: THE PRE-LAUNCH NEWS CONFERENCE PLAY
VIDEO: PRE-FLIGHT MISSION INTRODUCTION BRIEFING PLAY
VIDEO: GRAIL'S ROADMAP TO THE MOON PLAY | HI-DEF
VIDEO: DELTA/GRAIL LAUNCH ANIMATION PLAY | HI-DEF
VIDEO: GRAIL LUNAR MAPPING ANIMATION PLAY | HI-DEF
VIDEO: HOW GRAVITY MEASUREMENTS ARE MADE PLAY | HI-DEF

VIDEO: DELTA ROCKET'S NOSE CONE INSTALLED PLAY | HI-DEF
VIDEO: GRAIL MOVES TO ROCKET'S LAUNCH PAD PLAY | HI-DEF
VIDEO: SECOND SATELLITE PUT ON LAUNCH DEPLOYER PLAY | HI-DEF
VIDEO: FIRST SATELLITE PUT ON LAUNCH DISPENSER PLAY | HI-DEF

VIDEO: SOLAR ARRAYS UNFURLED FOR CHECK PLAY | HI-DEF
VIDEO: SATELLITES READY TO START TESTING PLAY | HI-DEF
VIDEO: UNBOXING THE SPACECRAFT AT ASTROTECH PLAY | HI-DEF
VIDEO: SATELLITES UNLOADED FROM TRANSPORT PLANE PLAY | HI-DEF
VIDEO: GRAIL SPACECRAFT TOUCH DOWN IN FLORIDA PLAY | HI-DEF

VIDEO: ROCKET'S SECOND STAGE INSTALLED PLAY | HI-DEF
VIDEO: SECOND STAGE CARTED TO COMPLEX 17 PLAY | HI-DEF

VIDEO: SOLID ROCKET BOOSTERS ATTACHED PLAY | HI-DEF
VIDEO: READYING THE FIRST SET OF BOOSTERS PLAY | HI-DEF

VIDEO: ON-PAD ASSEMBLY OF ROCKET UNDERWAY PLAY | HI-DEF
VIDEO: GANTRY HOISTS FIRST STAGE VERTICALLY PLAY | HI-DEF
VIDEO: FIRST STAGE ARRIVES AT THE PAD PLAY | HI-DEF
SUBSCRIBE NOW



STS-134 Patch

Free shipping to U.S. addresses!

The final planned flight of space shuttle Endeavour is symbolized in the official embroidered crew patch for STS-134. Available in our store!
 U.S. STORE
 WORLDWIDE STORE

Final Shuttle Mission Patch

Free shipping to U.S. addresses!

The crew emblem for the final space shuttle mission is now available in our store. Get this piece of history!
 U.S. STORE
 WORLDWIDE STORE

Apollo Collage
This beautiful one piece set features the Apollo program emblem surrounded by the individual mission logos.
 U.S. STORE

STS-133 Patch

Free shipping to U.S. addresses!

The final planned flight of space shuttle Discovery is symbolized in the official embroidered crew patch for STS-133. Available in our store!
 U.S. STORE
 WORLDWIDE STORE

Anniversary Shuttle Patch

Free shipping to U.S. addresses!

This embroidered patch commemorates the 30th anniversary of the Space Shuttle Program. The design features the space shuttle Columbia's historic maiden flight of April 12, 1981.
 U.S. STORE
 WORLDWIDE STORE

Mercury anniversary

Free shipping to U.S. addresses!


Celebrate the 50th anniversary of Alan Shephard's historic Mercury mission with this collectors' item, the official commemorative embroidered patch.
 U.S. STORE
 WORLDWIDE STORE
MISSION STATUS CENTER

INDEX | PLUS | NEWS ARCHIVE | LAUNCH SCHEDULE
ASTRONOMY NOW | STORE

ADVERTISE

© 2014 Spaceflight Now Inc.