A look back into History:

The amazing LRO images – now released by NASA – show details which even include the actual footprint paths made when the astronauts explored the lunar surface during the Apollo missions.

Other easily identifiable areas – such as in the Apollo 17 site – include the tracks laid down by the lunar rover, along with the last foot trails left on the moon.

At each site, trails also run to the west of the landers, where the astronauts placed the Apollo Lunar Surface Experiments Package (ALSEP) to monitor the moon’s environment and interior.

LRO – which was built and managed by NASA’s Goddard Space Flight Center – managed to take the higher resolution photos via adjustments made to the spacecraft’s orbit, which is slightly oval-shaped or elliptical.

The maneuver lowered LRO from its usual altitude of approximately 31 miles (50 kilometers) to an altitude that dipped as low as nearly 13 miles (21 kilometers) as it passed over the moon’s surface. The spacecraft remained in this orbit for 28 days, long enough for the moon to completely rotate.

This allowed for full coverage of the surface by the LROC’s Wide Angle Camera on the spacecraft.

“The new low-altitude images sharpen our view of the moon’s surface,” said Arizona State University researcher Mark Robinson, principal investigator for the Lunar Reconnaissance Orbiter Camera (LROC). “A great example is the sharpness of the rover tracks at the Apollo 17 site. In previous images the rover tracks were visible, but now they are sharp parallel lines on the surface.”

“Without changing the average altitude, we made the orbit more elliptical, so the lowest part of the orbit is on the sunlit side of the moon,” added Goddard’s John Keller, deputy LRO project scientist. “This put LRO in a perfect position to take these new pictures of the surface.”

The cycle ended on Tuesday, resulting in the spacecraft returning to its 31-mile orbit around the Moon.

“These images remind us of our fantastic Apollo history and beckon us to continue to move forward in exploration of our solar system,” said Jim Green, director of the Planetary Science Division at NASA Headquarters in Washington.

Protecting the Lunar Sites:

The amazing images were published just days ahead of the Delta II mission to launch GRAIL (Gravity Recovery and Interior Laboratory) – twin lunar satellites – to the Moon on Thursday, which lift-off scheduled for 8:37am Eastern from Cape Canaveral Air Force Station (CCAFS).

The images also arrived shortly after an expansive internal NASA presentation – available on L2 - was debated at a NASA Staff Senior meeting in August, which discussed the protection of the heritage sites from future landers and robotic vehicles.

Such new arrivals in the near future include private robotic landers, such as those competing for the Google Lunar X PRIZE (GLXP) – as heavily referenced in the associated NASA presentation.

The GLXP has a prize fund of $30 million available to the first privately funded teams to safely land a robot on the surface of the Moon, have that robot travel 500 meters over the lunar surface, and send video, images and data back to the Earth.

There are currently 29 teams working on winning the GLXP, with $20 million on offer for the winner. The targeted landing sites for these teams are located all around the lunar surface.

According to the NASA presentation there is scientific interest in robotic visits to the Apollo sites, allowing for the collection of data on items such as dust transportations, Micrometeorite bombardment rates, sandblasting effects, the survival of microbes and Lunar Weathering.

“To characterize the effects on engineered materials following four decades of exposure to the lunar environment,” the presentation noted on the latter scientific item of interest.

However, there is a concern relating to the possible mechanisms of damage to the aforementioned “scientifically interesting data” as NASA worded it.

Fears include the proximity of landing, liftoff and flyover from a future landing/robotic vehicle, where rocket thrust may erase footprints and treads, sandblast nearby hardware and cause deposition of chemicals/dust.

There are also concerns relating to robotic rovers accidentally running over the footprints created by Apollo astronauts, or contaminate a site via physical contact with heritage hardware.

One of the worst case scenarios listed relates to the potential of Entry, Descent and Landing (EDL) errors, resulting in a “crash or off-nominal landing near a heritage site which may produce enormous amounts of debris, dust, chemical contamination, and possible biological contamination.”

Some data is already at hand via the actual Apollo missions, such as the “Plume/Ejecta particle analysis for Lunar Descent Engines” findings, which show the descent engines create a high velocity of horizontal flow across the lunar surface.

The data – as presented in the NASA document – notes that the force creates a “relatively flat sheet of dust – 1-3 degrees to surface – with particles lifted by aero forces. Total eroded and scouring volume is around two metric tons in volume, with dust velocities reaching as high as 2000 meters per second.”

As such, NASA created a set of recommendations for preserving/protecting the USG Lunar Artifacts, relating to three categories, ranging from the six Apollo sites, the unmanned soft-landing sites of Surveyor and Luna, and through to the impact/crash sites of Ranger and the expended S-IVB stages.

Among the recommendations cited in the presentation, the arrival of future craft – such as the GLXP vehicles – should follow certain flight rules, in order to provide protection for the heritage sites.

“The approach path for the Descent/Landing (D/L) trajectory should be tangential to the D/L boundary in order to protect the site from off-nominal descent/landing situations,” the document noted. “The visiting vehicle should ensure no overflight of the heritage sites.”

The recommendations add additional emphasis for the Apollo 11 and Apollo 17 sites, making reference to a “Keepout Zone”.

“While all the Apollo sites represent significant historical/heritage value in the material culture, the Apollo 11 and 17 landing sites carry special significance,” added the presentation.

“It is recommended that the sites for Apollo 11 and 17 be treated as unique by prohibiting visits to any part of the site (and) that all vehicles remain beyond the boundaries of the entire site.

“It is recommended that the entire site at Apollo 11 and 17 be restricted from close inspection by visiting robotic systems. The visiting vehicle mobility exclusion boundary will encompass all artifacts (hardware, footprints, etc) for this site.”

The exclusion zone for Apollo 11′s site will result in a keep-out zone of 75 meters from the lunar module descent stage, where as the zone will extend 200-225 meters from the Apollo 17 site.

However, for the Apollo 12, 14, 15 and 16 sites, more access should be provided to individual components and artifacts, NASA added, allowing for future robotic missions to get within touching distance of Apollo hardware – as much as they won’t be allowed physical contact.

This additional access is shown as buffer zones, with a three meter buffer for descent stages, one meter buffer distance for the Lunar Rovers, experiments, sampling sites and flags, while no restrictions are recommended on the footprints and rover tracks outside the identified keep-out zones.

These buffer zones will also apply to other spacecraft, such as a one meter buffer around all Surveyor spacecraft hardware. A ruling is also provided for the expended S-IVB stage impact site.

“Rovers may drive to the rim of the crater and observe,” added the presentation. “Entrance into the crater may be permissible with coordination with NASA, but may not disturb any debris.”

An additional note on the restrictions at the Apollo 12, 14-16 sites, is also listed, relating to the Laser Ranging Retro-Reflectors (LRRRs), which the presentation notes should be carefully preserved.

“The LRRRs should be treated as special cases with approach mobility being tangential to the site. Once within a 10 meter radius zone of the LRRR, mobility can only proceed at speeds that do not propel regolith particles forward of the rover up to the total exclusion zone of one meter radius around the retro-reflector.

“Direct approach to the LRRR should never occur.”

Several pages of additional rules and allowances are listed for landers in the hopper configuration, along with the potential that the GLXP missions may provide additional science opportunities and data to use in refining their rulings.

As such, NASA class the recommendations as an evolving document, based on early, small landers with imaging only. Such lander capabilities are likely to advance over the short-term.

Forward work will also include analysis on rocket exhaust interaction with the lunar regolith to attempt to reduce the D/L distance.

(Images: Via the NASA Presentation – available in L2, NASA images via the LRO photo release. The lunar landing site map is originally available here: http://evadot.com/glxplandingsites/)

(As the shuttle fleet retire, NSF and L2 are providing full transition level coverage, available no where else on the internet, from Orion and SLS to ISS and COTS/CRS/CCDEV, to European and Russian vehicles. 

(Click here to join L2: http://www.nasaspaceflight.com/l2/ )

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Atlas V/Launch Overview:

The veteran Atlas V rocket – making its 19th lunar flight – that will loft the LRO/LCROSS dual payload to the moon will fly in the 401 configuration with a four-meter fairing, no solid rocket boosters and a single-engine Centaur upper stage.

Given the precise nature of the LRO/LCROSS missions, the launch window is four days in duration – lasting from June 17 to June 20.

For its opening launch attempt on June 18, the Atlas team will have three opportunities to launch the pair of lunar satellites on their mission. The first attempt comes at 5:12pm EDT, with subsequent attempts available at 5:22pm and 5:32pm. Due to weather, controllers opted for the final available attempt.

For launch day, the 45th Weather Squadron of the Air Force is predicting a 40 percent chance of violating weather constraints – with the main concerns being anvil clouds, cumulus clouds, and rain within 10nm of the launch pad/flight path.

The weather forecast, at this time, remains essentially unchanged in the event of a 24-hour or 48-hour scrub turnaround.

In the event of a launch on June 19, the three launch times are: 6:41pm, 6:51pm, and 7:01pm. Similarly, if launch should occur on June 20, the launch times are: 8:08 pm, 8:18 pm. and 8:28 pm.

If, for some reason, the Atlas team is not able to achieve launch by June 20, the next four day launch window starts June 30.

LRO:

The primary satellite for this mission is the Lunar Reconnaissance Orbiter (LRO).

LRO, which sits on top of the LCROSS experiment for launch, will be released from its LCROSS companion after it is placed on its lunar-transfer trajectory to enter lunar orbit approximately four days after launch from Cape Canaveral.

LRO is expected to have a two month commissioning period prior to beginning its one year primary science mission.

In all, the LRO spacecraft has six primary instruments: CRater, DLRE (Diviner Lunar Radiometer Experiment), LAMP, LEND (responsible for acquiring high-resolution neutron datasets), LOLA, and LROC.

In particular, one of LRO’s six primary instruments is the DLRE – the first instrument to “systematically map the global thermal state of the Moon and its diurnal and seasonal variability.”

During LRO’s primary one year science mission, the DLRE will be capable of locating resources critical to humanity’s return to the moon – currently scheduled for the end of the next decade.

DLRE will be responsible for creating detailed, global maps of the lunar surface temperature over the lunar day and year, assessing the stability of potential polar ice deposits, mapping compositional variations in the lunar surface, and allowing lunar scientists to identify potential hazards on the lunar surface such as roughness of the terrain and rock concentration.

As a side note, the DLRE will also be able to detect the lunar rover tracks and the six descent stages left behind from the various Apollo missions in the late 1960′s and early 1970′s.

Overall, the main science goals for DLRE – identified by the science team and NASA – are: “Mapping global day/night surface temperatures, characterizing thermal environments for habitability, determining rock abundance at potential landing sites, identifying polar cold traps and potential polar ice deposits, and mapping variations in silicate mineralogy.”

To accomplish these objectives, DLRE will collect measurements on reflected solar and emitted infrared radiation along nine spectral channels with wavelengths between 0.3 and 400 microns.

Among these nine channels are “two solar reflectance channels, three mineralogy channels, and four thermal channels.”

These particular channels are distributed between two identical, bore-sighted telescopes – telescopes A and B. These telescopes are 3-mirror, off-axis, focal length 1.7 telescopes with 4-centimeter apertures.

Telescope A will monitor channels between 0.35 and 23 microns, where Telescope B will monitor channels between 25 and 400 microns.

The DLRE will be positioned primarily in a nadir orientation. It is mounted on the nadir panel of the LRO which will allow the instrument continuous views of the lunar surface as LRO’s other instruments conduct their observations or — thanks to two actuators which allow 270 degrees of motion – a view of space.

One of the reasons this instrument is so important to the LRO team and NASA is its ability to increase our knowledge of the lunar seasons and lunar thermal environments.

As the DLRE fact sheet indicates, the moon’s surface thermal environment is among the most extreme of the planetary bodies in our solar system – representing a unique challenge to future human settlements and robotic mission to our natural satellite as all spacecraft and housing units will have to be able to withstand the drastic thermal changes present on the moon.

In particular, there are three thermal areas on the moon: daytime, nighttime, and polar.

Specifically, the moon’s daytime thermal environment is controlled by “the flux of solar radiation” – allowing temperatures to reach as high as 260 degrees F/127 degrees C. In contrast, the 14-day lunar night cycle sees temperatures of -179 degrees F/-173 degrees C.

However, the lunar polar regions’ thermal characteristics are more complex. Essentially, the topography and lunar seasons play a large role in determining the polar regions’ thermal properties.

While parts of the polar regions receive very little direct illumination from the sun, others receive permanent illumination or no illumination at all. In the regions that receive very little sunlight, it is currently thought that the daily temperatures range from -297 degrees F/-182 degrees C to -387 F/-232 C – possibly even lower.

By using the DLRE and LEND instruments, NASA and lunar scientists will be able to correlate hydrogen abundance with cold-trap surface and subsurface temperatures.

To this end, high levels of hydrogen would lend evidence to the presence of cold-trapped water ice – an important find for the future of human exploration of the solar system.

LCROSS:

NASA’s Lunar CRater Observation and Sensing Satellite (LCROSS) was selected in April 2006 as a “low-cost, fast track companion mission for LRO.”

Designed to answer the question “Does water exist in a permanently shadowed lunar crater,” the LCROSS experiment will utilize a “shepherding spacecraft” packed with instrumentation and the Atlas V’s Centaur upper stage to complete its mission objectives of smashing into a permanently shadowed crater on the moon’s south pole and examining the ejecta plume for traces of water and other minerals/materials that might be useful to future human settlements on our closet cosmic neighbor.

To accomplish these objectives, the LCROSS part of the mission will separate from the LRO satellite shortly after the combined spacecraft is put into it lunar-transfer trajectory.

After separation from LRO, a guided blow down – blowing cold propellants through the Centaur’s engine, without igniting the engine, to get a few hundred pounds of thrust – will be performed to place LCROSS on course of its elongated Earth orbit and eventual impact with south pole lunar crater.

After that, the Centaur upper-stage with the attached shepherding spacecraft will be put into a flat-spin to deplete propellants and inert the centaur upper-stage so no contaminants are introduced to the lunar crater during the Centaur impact roughly 100-days later in early October (9th – 11th depending on launch day).

After a nearly 100-day coasting phase to properly align the combined satellite and impactor with its final crater target, the LCROSS satellite will separate from the Centaur upper stage.

After firing its thrusters to slightly lower its velocity, the LCROSS shepherding satellite will trail about four minutes behind the Centaur upper stage, flying through the ejecta cloud created by the Centaur’s impact with the lunar surface.

After flying through the debris cloud – collecting invaluable scientific data and transmitting that data real-time to Earth – the LCROSS shepherding satellite will also impact the lunar surface, creating a second debris cloud.

Onboard the LCROSS shepherding spacecraft will be a host of scientific instruments including two near-infrared spectrometers, a visible light spectrometer, two mid-infrared cameras, two near-infrared cameras, a visible camera, and a visible radiometer.

These instruments were selected to “provide mission scientists with multiple complimentary views of the debris plume created by the Centaur impact,” notes a NASA fact sheet about the mission.

Following the Centaur’s impact in a predetermine crater, the ejecta cloud will rise above the surface of the crater’s rim – thereby exposing the ejecta to sunlight. Once this occurs, any water, hydrocarbons, or organic materials will vaporize or sublimate and break down into their basic components.

It is these components at the LCROSS shepherding spacecraft will monitor and analyze as it passes through the ejecta cloud before its impact to the lunar surface.

The near-infrared and mid-infrared cameras will help determine the total amount and distribution of water in the debris plume while the visible radiometer will monitor the flash created by the Centaur’s impact on the surface.

Based on a launch during the June 18th - 20th window, both debris plumes from Centaur and LCROSS’ shepherding spacecraft are expected to be visible from Earth-based telescopes of 10- to 12 inches and larger across the continental U.S.

The plumes are also expected to be visible from space-based telescopes as well – including the recently upgrading Hubble Space Telescope.

The LCROSS mission is expected to expedite our search for water ice on the moon using information gathered from the Clementine and Lunar Prospector missions in 1994 and 1998, respectively.

Together, the LRO/LCROSS missions – which are components of the Lunar Precursor Robotic Program from the Marshall Spaceflight Center in Huntsville, AL – will help map the moon’s surface and pave the way for future robotic and human missions to the moon in the years to come.

As Todd May stated in the LRO/LCROSS pre-launch briefing on Monday, “LRO and LCROSS will give us the information about the moon that we already have about Mars.”

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