Grail Gravity Maps of the Moon

Gravity Maps
Grail Gravity Maps of the Lunar Highlands
Image Credit: NASA / JPL-Caltech / MIT / GSFC

NASA released this graphic of the front (left) and back (right) of the Moon, based on gravity data from NASA’s GRAIL mission and topography data from NASA’s Lunar Reconnaissance Orbiter.

The graphic shows regions of high and low densities of the lunar highlands. Red is high and blue is low. White shows mare basalt regions and solid circles are prominent impact basins.

On the back side of the Moon, the South Pole-Aitken basin, has a higher than average density that reflects its atypical iron-rich surface composition.

Below is a highly detail gravity map of the front (visible) side of the Moon. You can watch the movie.

Visible Side
Grail Gravity Map of the Visible Side of the Moon
Image Credit: NASA / JPL-Caltech / MIT / GSFC


Lunar Topographic Map

Progress M-13M
100 meter resolution lunar topographic map
Image Credit: NASA’s Goddard Space Flight Center / DLR / ASU

NASA has released a nearly complete topographic map of the Moon at a resolution of 100 meters (the Global Lunar DTM 100 m topographic model – GLD100)

With the Lunar Reconnaissance Orbiter (LRO) Wide Angle Camera and the Lunar Orbiter Laser Altimeter (LOLA) instrument, scientists can now accurately portray the shape of the entire moon at high resolution.

Additional information can be found at the Lunar Reconnaissance Orbiter Camera center at Arizona State University.

1959 – Twelve Men On The Moon

Copernicus, Eratosthenes and Project Horizon
Image Credit: NASA / GSFC / Arizona State University

The Lunar Reconnaissance Orbiter Camera team recently released this image featuring the famous crater Copernicus with its ejecta splashed across much of the face of the Moon. Copernicus and the crater Eratosthenes lie just south of Mare Imbrium. To the east of Copernicus and south of Eratosthenes lies the nearly featureless plain called Sinus Aestuum. Here, just southeast of Eratosthenes lies the location of a proposed Moon Base. In addition to the scientific value of this area, the rich ores of the Rima Bode regional dark mantling deposit lie nearby.

On 20 March 1959, Arthur G. Trudeau, Chief of Research and Development for the U.S. Army, submitted a request for the study to place a lunar outpost on the Moon. The result was Project Horizon, a plan (dated 9 June 1959) to place a military base with 10-20 men on the surface of the Moon by 1965. Full details are in Vol. I and Vol. II (pdf).

The introduction to the proposal stated that the establishment of a lunar base would:

  • Demonstrate the United States scientific leadership in outer space
  • Support scientific explorations and investigations
  • Extend and improve space reconnaissance and surveillance capabilities and control of space
  • Extend and improve communications and serve as a communications relay station
  • Provide a basic and supporting research laboratory for space research and development activity
  • Develop a stable, low-gravity outpost for use as a launch site for deep space exploration
  • Provide an opportunity for scientific exploration and development of a space mapping and survey system
  • Provide an emergency staging area, rescue capability or navigational aid for other space activity

It further stated the following, prescient about the Soviet manned capability, but extremely optimistic about the timetable for the Moon Base:

Advances in propulsion, electronics, space medicine and other astronautical sciences are taking place at an explosive rate. As recently as 1949, the first penetration of space war accomplished by the US when a two-stage V-2 rocket reached the then unbelievable altitude of 250 miles. In 1957, the Soviet Union placed the first man-made satellite in orbit. Since early l958, when the first US earth satellite was launched, both the US and USSR have launched additional satellites, moon probes, and successfully recovered animals sent into space in missiles. In 1960, and thereafter, there will be other deep space probes by the US and the USSR, with the US planning to place the first man into space with a REDSTONE missile, followed in 1961 with the first man in orbit. However, the Soviets could very well place a man in space before we do. In addition, instrumented lunar landings probably will be accomplished by 1964 by both the United States and the USSR. As will be indicated in the technical discussions of this report, the first US manned lunar landing could be accomplished by 1965. Thus, it appears that the establishment of an outpost on the moon is a capability which can be accomplished.

Underlying all of this was the traditional von Braun team approach:

paramount to successful major systems design is a conservative approach which requires that no item be more “advanced” than required to do the job. It recognizes that an unsophisticated success is of vastly greater importance than a series of advanced and highly sophisticated failures that “almost worked. “

The proposal discusses the ongoing development of the Saturn I by ARPA, expecting it would be fully operational by 1963. The Saturn I stood more than 200 feet tall, and would be superseded by the Saturn II in 1964, standing 304 feet tall. By the end of 1964, a total of 72 Saturn I rockets would have been launched on various programs of discovery, including 40 to support the manned lunar base. In order to support the full complement of 12 men, 61 Saturn I and 88 Saturn II launches would be required by the end of 1966, landing 490,000 pounds of cargo on the lunar surface. 64 launches were scheduled for 1967, landing an additional 266,000 pounds of supplies. The total cost of the eight and one-half year program was estimated to be $6 Billion.

The von Braun team thought very large indeed.

Lunar Base
Project Horizon – Lunar Base 1965
Image Credit: US Army

Project Horizon – Rockets
Image Credit: US Army

Orbital Trajectories
Image Credit: US Army

Let us know what you think. What do you want to know about? Post a comment.


The Gravity Recovery and Interior Laboratory
Image Credit: NASA / JPL / MIT

GRAIL is one of those nifty experiments. Relatively small, GRAIL consists of two spacecraft weighing less than 500kg each. Orbiting the Moon, the two craft will piece together an extremely detailed map of the Moon’s gravitational field. This will allow scientists to construct a model of the interior structure of the Moon from crust to core.

The two GRAIL spacecraft will be launched aboard a Delta II rocket during a 26 day window, which opens on 8 September 2011. Lasting only 90 days, the mission is designed to avoid the lunar eclipses of 10 December 2011 and 4 June 2012.

The GRAIL mission’s principal investigator is Maria Zuber, who is chair of MIT’s Department of Earth, Atmospheric and Planetary Science. In 2008, she was selected by NASA as the first woman ever to head a major planetary robotic research mission.

The GRAIL spacecraft design and their components are derived from Lockheed Martin’s XSS-11 (pdf) spacecraft heritage. GRAIL’s science team includes NASA Goddard Space Flight Center, JPL, the Carnegie Institution of Washington, the University of Arizona, the University of Paris and the Southwest Research Institute.

Four of the Science Team members (Frank Lemoine, Greg Neumann, Dave Smith, Maria Zuber) have ties to current lunar missions (LRO and Kaguya/SELENE)

The GRAIL spacecraft is designed to conduct the following measurements:

  • Map the structure of the crust & lithosphere
  • Understand the Moon’s asymmetric thermal evolution
  • Determine the subsurface structure of impact basins and the origin of mascons
  • Ascertain the temporal evolution of crustal brecciation and magmatism
  • Constrain deep interior structure from tides
  • Place limits on the size of the possible inner core

The GRAIL website describes the mission objectives this way:

The Grail Spacecraft
Image Credit: NASA / JPL / MIT

The Moon is the most accessible and best studied of rocky, or “terrestrial”, bodies beyond Earth. Unlike Earth, however, the Moon’s surface geology preserves the record of nearly the entirety of 4.5 billion years of solar system history. Orbital observations combined with samples of surface rocks returned to Earth, show that no other body preserves the record of geological history so clearly as the Moon.

The structure and composition of the lunar interior (and by inference the nature and timing of internal melting and heat loss) hold the key to reconstructing this history. Longstanding questions such the origin of the maria, the reason for the nearside-farside asymmetry in crustal thickness, and the explanation for the puzzling magnetization of crustal rocks, all require a greatly improved understanding of the Moon’s interior. Deciphering the structure of the interior will bring understanding of the evolution of the Moon itself, and also extend knowledge of the origin and thermal evolution of the Moon to other bodies in the inner solar system. For example, while the Moon was once thought to be unique in developing a “magma ocean” shortly after accretion, and now such a phenomenon has now been credibly proposed for Mars as well.

Let us know what you think. What do you want to know about? Post a comment.

LCROSS – IMPACT Imaged by Diviner on LRO

From the UCLA Diviner LRO blog:

The LRO Diviner instrument obtained infrared observations of the LCROSS impact this morning. LRO flew by the LCROSS Centaur impact site 90 seconds after impact at a distance of ~80 km. Diviner was commanded to observe the impact site on eight successive orbits, and obtained a series of thermal maps before and after the impact at approximately two hour intervals at an angle of approximately 48 degrees off nadir. In this viewing geometry, the spatial footprint of each Diviner detector was roughly 300 by 700 meters.

Diviner Impact Images of LCROSS

Credit: NASA / GSFC / UCLA

From the Planetary Society Blog:

preliminary, uncalibrated Diviner thermal maps of the impact site acquired two hours before the impact, and 90 seconds after the impact. The thermal signature of the impact was clearly detected in all four Diviner thermal mapping channels.

LCROSS – Impact

Images and Events of the final hour of the LCROSS mission.

3:42 – I MB data rate has been confirmed

3:43 – First Image from LCROSS Shepherding Spacecraft

3:48 – All Payload Instruments are Operating Nominally

3:59 – 3500 MPH at 3400 Miles from the Moon

4:23 – Poll of All Systems Ready for Observing Impact

4:31 – Impact of Centaur Stage

4:35 Impact of LCROSS Shepherding Spacecraft

A possible impact image in the infrared can be seen at the forum at

Centaur After Separation

Centaur after Separation #1 with Low Data Rate Transmission

Centaur after Separation

Centaur after Separation #2 with Low Data Rate Transmission

First Image of Moon

First Image of Moon after High Data Rate Enabled

Image 2

Lunar Image

10 Minutes
10 Minutes Before Impact
Aim Point

Aim Point at Cursor Arrow

4 Minutes Infrared

4 Minutes Infrared Image

1 Minute Flash Mode

1 Minute – Transition to Flash Mode

30 Seconds30 Seconds 30 Seconds Infrared30 Seconds Infrared
15 Seconds Infrared15 Seconds Infrared 10 Seconds10 Seconds – Small Crater Visible at Top
LOSLoss of Signal It will be several days before the data has been calibrated and results begin to be released.

Credit: Screen Shots of NASA TV Images

LCROSS – Brace for Impact


Credit: NASA Image

Tomorrow morning at 4:31:20 PDT (Phoenix time), the Centaur upper stage of the LRO mission will impact Cabeus crater on the Moon. At 4:35:39 the LCROSS instrument package will impact the Moon, having recorded the Centaur impact with a variety of imaging and spectroscopic instruments.

What are we looking for? WATER. Worth its weight in gold.

A complete list of events leading up to impact can be found at the LCROSS Flight Director’s Blog. Key events:

  • 01:00 PDT: Final orbit determination delivery for Separation(completed)
  • 17:00 PDT: Slow rotation to Separation attitude starts
  • 18:50 PDT: Separation
  • 19:30 PDT: Braking Burn starts (LCROSS)
  • 03:00 PDT: Start of Impact onboard command sequence
  • 3:36 PDT: Payload powers on
  • 4:10 PDT: Total Luminescence Photometer (TLP) Instrument powers on
  • 4:30:20 PDT: Flash Mode begins
  • 4:31:20 PDT: Centaur Impact
  • 4:31:23 PDT: Curtain Mode begins
  • 4:34:23 PDT: Crater Mode begins
  • 4:35:39 PDT: Shepherding Spacecraft impact

The latest LCROSS news can be found here.

Watch the LCROSS impact live starting at 3:30 PDT on NASA TV.

You can follow the live blog at NasaSpaceFlight. Current comments on the last page listed in the upper left.