LCROSS Impacts Moon, Science Data Pending


UPDATE: The MMTO Telescope on Mount Hopkins in Arizona has video from their observations that, while fuzzy, possibly show a bright plume emerging from the crater. (Further analysis says probably not). The video is here,,

In a bit of an anti-climax, the Centaur second stage, and later the LCROSS spacecraft impacted Cabeus Crater but produced no visible plume. Analysis of navigation telemetry indicated the trajectory was spot on, and the Centaur should have hit the surface to within about 64 meters (210 feet) of the planned target. The video above is from NASA TV, and below if video from the Lick Observatory, whose 36-inch telescope was trained on the Moon’s south pole. They didn’t see anything, as reports from telescopes at Palomar, Arizona, and Mauna Kea also confirmed. But a dim impact would mean regolith ejecta, which scientists say is good because that means it hit more dirt than rocks. Another thing to remember is that science is not always “seen” in visible light. The LCROSS sensors and instruments will provide the best data.

I’ll post more later after the LCROSS press conference at 9 am CDT. In the meantime, enjoy these animations created by Emily Lakdawalla of the Planetary Society from the LCROSS camera as it approached the Moon — very nice!
Continue reading “LCROSS Impacts Moon, Science Data Pending”

LCROSS (and the Moon) Up Close

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The LCROSS spacecraft will be giving it all up for science Friday morning when it and the second stage of the Centaur rocket impact Cabeus crater on the Moon’s south pole, searching for possible water ice hidden inside the perpetually dark portions of the crater. Since we’ll never see LCROSS again, its only fitting to take a good long, last look at her. Solar System Ambassador and Planetary Society volunteer Ken Kremer had the wonderful opportunity to see both LCROSS and her sister ship the Lunar Reconnaissance Orbiter (LRO) in the Astrotech Space Operations Facility clean room in Titusville, FL earlier this year before the dynamic duo launched together on June 18. Ken has graciously given permission to allow us to publish these images (which were previously posted on the Planetary Society website) so we can all remember what she looked like. Above is a side view of LCROSS wrapped in gold multi-layer thermal insulation. The solar array is on the left side. Science instrument, avionics, navigation, communication and thruster equipment panels encircle and are attached to the central payload adapter ring. The star tracker is on the right side, and the payload fairing halves sit at either side.

More images below.

LRO, LCROSS and Ken Kremer.  Credit: Ken Kremer and the Planetary Society.
LRO, LCROSS and Ken Kremer. Credit: Ken Kremer and the Planetary Society.

Here’s a picture of Ken with the two spacecraft. Visible are the solar arrays for LRO (top, left) and LCROSS (bottom, left). Visible is the LCROSS panel with the 9 science instruments (gold color) which run on just 100 watts of power. Above Ken’s head is the visible light camera.

LRO (gray) and LCROSS (yellow) lunar spacecraft stacked adjacent to Atlas V payload fairing at Astrotech Payload Facility on May 15, 2009.  Credit: Ken Kremer and the Planetary Society.
LRO (gray) and LCROSS (yellow) lunar spacecraft stacked adjacent to Atlas V payload fairing at Astrotech Payload Facility on May 15, 2009. Credit: Ken Kremer and the Planetary Society.


This image really provides a reference to how big these two spacecraft actually are. Note the person in the bunny (clean) suit standing next to LRO (gray) and LCROSS (yellow) lunar spacecraft stacked adjacent to Atlas V payload fairing.

And since we’ve now seen LCROSS up close, here’s a few new close-up images just released by NASA of Cabeus crater.

A birds-eye view of Cabeus crater, LCROSS' target.  Credit: NASA/Goddard Space Flight Center Scientific Visualization Studio
A birds-eye view of Cabeus crater, LCROSS' target. Credit: NASA/Goddard Space Flight Center Scientific Visualization Studio

This visualization image gives a bird’s-eye view of Cabeus crater and the target zone for the crash site. A 3.5-kilometer-wide “flagpole” marks the targeted location within the crater. Colored stripes on the pole indicate one kilometer steps in elevation above the crater floor, black stripes indicate 5 kilometer steps. The pole stands 25 kilometers tall, and the blue rings mark heights of 50 and 100 kilometers above the impact site.
Key landmarks to locate Cabeus Crater.  Credit: NASA/Goddard Space Flight Center Scientific Visualization Studio
Key landmarks to locate Cabeus Crater. Credit: NASA/Goddard Space Flight Center Scientific Visualization Studio

This image shows key lunar landmarks used to locate Cabeus crater. The yellow scale shows angular distances in the plane of the impact site; blue arcs show heights 50, 100 and 200 kilometers above it.

And click here for a link to a video visualization that zooms into Zoom into the Moon as it might look shortly after the LCROSS impact. Blue arcs represent 50, 100 and 200 kilometer heights above the crash site.

Hopefully the telescopes trained on this region of the Moon will give us the real images of this event!

Lead image caption: LCROSS Close Up. Side view of LCROSS wrapped in gold colored multi layer thermal insulation. Note solar array at left. Science instrument, avionics, navigation, communication and thruster equipment panels encircle and are attached to the central payload adapter ring. Star tracker at right. Payload fairing halves sit at either side.
Credit: Ken Kremer

Sources: Ken Kremer and the Planetary Society Blog, Goddard Space Flight Center

No, NASA Is Not Bombing the Moon

There seems to be a little lunacy making the rounds that NASA is going to “bomb” the Moon on Friday morning, or “hurt the Moon,” or “split the Moon in half,” or change its orbit. This is all just nonsense and scare-mongering, and those worried about our Moon can rest assured our lunar companion will remain in the sky relatively unchanged after this experiment to search for water ice on the Moon’s south pole. Let’s take a look at the physics involved and what might happen to the Moon.


First of all, there are no explosives involved. The LCROSS mission is going sending a upper stage of a Centaur rocket and a smaller spacecraft to impact the Moon. The two objects will create a crater — The 5,000-pound (2,270-kilogram) Centaur is expected to slam into Cabeus Crater on the Moon’s south pole at a sharp angle at a speed of 5,600 mph (9,000 kilometers per hour). The Centaur’s collision is expected to create a crater roughly 60 or 70 feet wide (20 meters wide) and perhaps as much as 16 feet (5 meters) deep, ejecting approximately 385 tons of lunar dust and soil — and hopefully some ice.

The LCROSS spacecraft itself, weighing in at 1,500-pounds (700-kilograms), will follow the Centaur by about four minutes and fly through the regolith plume thrown up by the collision, just before it too slams into the lunar surface, kicking up its own smaller plume of debris, all the while using its sensors to look for telltale signs of water, beaming the information back to Earth.

So, yes, it will make a rather big crater on the Moon. But one close-up look at the lunar surface will reveal that the Moon is full of craters, and still regularly receives hits by meteorites and larger space rocks – not as much as in the past, as most of the craters on the Moon are from an earlier period in our history when there was more debris left over from the formation of the solar system. The Moon was not “hurt” in the past, and it will not get hurt by this impact. Additionally, other spacecraft have hit the lunar surface with no adverse effects on the Moon or its orbit.

But will this impact change the Moon’s orbit? Dr. Jeff Goldstein from the National Center for Earth and Space Science Education writes about this on his blog, Blog on the Universe:

The Atlas V Centaur upper stage has a mass of 2,000 kg (the more massive of the two vehicles impacting the Moon). It will be moving at 5,600 mph (2.5 km/sec.) BAM! By comparison, the Moon is orbiting the Earth at the measely speed of 2,300 mph (1.022 km/sec). On the other hand, the Moon is just a tad bit more massive than the specks on a collision course.

So let’s say we wanted to change the Moon’s speed by JUST 1 MPH (0.0004 km/sec)—which is less than 1/2,000th its orbital speed—and we were going to do it by hurling Atlas V Centaur upper stages at the Moon. How many would we have to hurl its way? HEY, let’s give every person on planet Earth an opportunity to hurl one. Would that do it? Uh … nope. Every person on Earth (all nearly 7 billion of us) would each need to hurl 1 MILLION Atlas V Centaur upper stages at the Moon. I’d rather just hurl one and not worry about it. Rest easy, sleep well, and let’s see if we can find water on the Moon at the South Pole.

Another question people have been asking: Will the impact destroy the water we are looking for?

NASA answers that question on the LCROSS FAQ site:

The LCROSS impact will have the same effect on the water (if it is indeed there) as any other object that might naturally impact it. Most (>90%) of any water that is excavated by LCROSS will most likely return to nearby “cold traps”. The LCROSS impact is actually a slow impact and, thus, most of the material is not thrown very high upward, rather outward, adjacent to the impact site. Of the water that does get thrown upward, much of it will actually return to the Moon and eventually find its way back to the dark, cold craters. This is actually one possible way that the water was supplied in the first place: it was deposited following the impacts of comets and asteroids.

There is about 12,500 square km of permanently shadowed terrain on the Moon. If the top 1 meter of this area were to hold 1% (by mass) water, that would be equivalent to about 4.1 x 1011 liters of water! This is approximately 2% the volume of the Great Salt Lake in Utah. The LCROSS impact will excavate a crater approximately 20 meters in diameter, or about one-trillionth the total permanently shadowed area. It is safe to say the LCROSS impact will not have a lasting effect on lunar water, if it does indeed exist.

See our previous article on how to watch the LCROSS event.

Guide to Seeing the LCROSS Lunar Impact

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The LCROSS spacecraft is going to impact the Moon on Friday, October 9, and here’s your chance to watch the action, either just for fun, or to contribute to scientific observations. Whether you want to observe with your own equipment or watch the event on television or a webcast, below you’ll find all the information and links you should need to be a part of history. Amateur astronomers need a 10-inch or bigger telescope to make observations.

When: Following the latest trajectory correction maneuvers, the time of impact on Friday, October 9, 2009 is 11:31:19 UTC for the Centaur and 11:35:45 for LCROSS spacecraft (7:31:19 a.m. EDT and 7:35:45 a.m. EDT).

The impact time may be refined as the time for impact comes closer. You can check the LCROSS mission Facebook and Twitter pages for the latest updates (and we’ll try to post it here as soon as possible after any changes are announced.) Also check this NASA website for more information.

Where: both spacecraft are targeting Cabeus crater. The impact site coordinates are -84.675, 311.275 E. Click here to download the Targeting Coordinates, Timing, and Finder Charts presentation for detailed information. (Powerpoint presentation.)

New Mexico State University and Marshal Space Flight Center have made finder charts available based on similar illumination and libration that we expect to see on the night of the impact.

In general, here’s where to look: Start with the south pole (bottom edge) and look for the terminator, or where the sunlight and shadow merge. Here’s what the Moon should look like:

Moon oct 9

Zoom in with your telescope and identify the Cabeus craters. The target is in Cabeus proper, near the bottom of the Moon. Here’s what it should look like, along with a notated image:

Craters on the Moon's south pole.
Craters on the Moon's south pole.

What will I see? Based on an projections, there should be a visible ejecta cloud rising to 6Km above the lunar surface and crater wall. Latest estimates of the Cabeus proper crater impact site indicate the first two or three kilometers of that plume height (the brightest parts) may not be viewable from Earth, but that the plume will hopefully have crater wall shadow behind it to help us see it. Impact design location is to maximize the amount of this in sunlight, but variables here will determine how much of it is actually illuminated, and it may be that only the high power instruments will see good contrast. But we don’t know for sure.

“We expect the debris plumes to be visible through mid-sized backyard telescopes—10 inches and larger,” says Brian Day of NASA/Ames. Day is an amateur astronomer and the Education and Public Outreach Lead for LCROSS. “The initial explosions will probably be hidden behind crater walls, but the plumes will rise high enough above the crater’s rim to be seen from Earth.”

See this page for more information.

What is actually going on? The 5,000-pound (2,270-kilogram) Centaur is expected to slam into Cabeus at a sharp angle at a speed of 5,600 mph (9,000 kilometers per hour). If all goes according to schedule, the shepherding vehicle, carrying nine science payloads, will follow the Centaur’s plunge into the moon, and send back data live to Earth. The Centaur’s collision is expected to create a crater roughly 60 or 70 feet wide (20 meters wide) and perhaps as much as 16 feet (5 meters) deep, ejecting approximately 385 tons of lunar dust and soil — and hopefully some ice. In addition to recording the collision, the shepherding spacecraft weighing, 1,500-pounds (700-kilograms) will fly through the regolith plume thrown up by the collision, just before it too slams into the lunar surface some four minutes later, kicking up its own smaller plume of debris, all the while using its sensors to look for telltale signs of water.

What if it is cloudy where I live, or I live in Europe/Asia and it is daytime, or I don’t have a telescope to watch?

You can watch the event on NASA TV, and here’s where you can watch it online.

Slooh is having a webcast and will have two telescopes trained on the impact site.

The Exploratorium is also showing a webcast.

If you want to watch with other space enthusiasts, check out this list of people and organizations that are sponsoring observing parties.

Also, if you are in Mumbai, India the Nehru Planetarium there has a free viewing of the event at 4 pm IST. (thanks for pradx on Twitter for that info.)

If you are in the Pasadena area, JPL’s Von Karman Auditorium will have a public viewing, opening the gates 3:00 am. local time.

SMART -1 Updates Image for LCROSS Impact

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Since the LCROSS team reloaded and switched which lunar crater they are targeting for impact with the spacecraft and its upper stage of the Centaur rocket on October 9, the SMART-1 team has reloaded as well, and has released an updated image of the new crater. LCROSS (Lunar Crater Observation and Sensing Satellite) will search for water ice on the Moon by making two impacts into Cabeus crater at the lunar South Pole. The impacts are scheduled for 11:31:19 UTC and 11:35:45 UTC.

Previously, the SMART-1 team had released an image of Cabeus A, the original target crater.
Bjoern Grieger, the liaison scientist for SMART-1’s AMIE camera, and Bernard Foing, ESA SMART-1 Project Scientist, searched through SMART-1’s database for images of Cabeus, taken four years ago. The
SMART-1 images are at high resolution as the spacecraft was near its closest distance of 500 km from the South Pole.

The Cabeus crater interior is permanently shadowed, so ice lying inside the crater could be protected from the Sun’s harsh rays. LCROSS will send the upper stage Centaur rocket crashing into Cabeus and a
shepherd spacecraft will fly into the plume of dust generated and measure its properties before making a second impact with the lunar surface. Astronomers will observe both impacts using ground and space-based telescopes. The SMART-1 spacecraft also concluded its mission with a controlled bouncing impact on September 3, 2006. The event was observed with ground-based telescopes (a “dry run” for LCROSS), and the flash from the impact was detected at infrared wavelengths.

“The Cabeus topographic features as observed by SMART-1 vary greatly during the lunar rotation and the yearly seasons due to the polar grazing illumination conditions,” said Foing. “The floor of Cabeus
near LCROSS targets shows a number of small craters and seems old enough to have accumulated water ice delivered from comets and water-rich asteroids, and might have kept it frozen in its shadowed
area.”

Source: ESA

LCROSS Team Changes Target Crater for Impact

LCROSS Mission

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Based on new analysis of the latest lunar data, the science team for NASA’s Lunar Crater Observation and Sensing Satellite mission (LCROSS) decided to change the target crater for impact from Cabeus A to Cabeus (proper). The decision was based on a consensus that Cabeus shows, with the greatest level of certainty, the highest hydrogen concentrations at the south pole. The most current terrain models provided by JAXA’s Kaguya spacecraft and the LRO Lunar Orbiter Laser Altimeter (LOLA) was important in the decision process, as the latest models show a small valley in an otherwise tall Cabeus perimeter ridge, which will allow for sunlight to illuminate the ejecta cloud, making it easier to see from Earth.

The decisison was based on continued evaluation of all available data and consultation/input from members of the LCROSS Science Team and the scientific community, including impact experts, ground and space based observers, and observations from (LRO), Lunar Prospector (LP), Chandrayaan-1 and JAXA’s Kaguya spacecraft. This decision was prompted by the current best understanding of hydrogen concentrations in the Cabeus region, including cross-correlation between the latest LRO results and LP data sets.

As for the sunlight illuminating the ejecta cloud on Oct. 9, it should show up much better than previously estimated for Cabeus. While the ejecta does have to fly to higher elevations to be observed by Earth telescopes and observers, a shadow cast by a large hill along the Cabeus ridge, provides an excellent, high-contrast, back drop for ejecta and vapor measurements.

See this link for how to observe the impact from Earth. Eastern and central north America has the best chance of seeing the impact.

The LCROSS team concluded that Cabeus provided the best chance for meeting its mission goals. The team critically assessed and successfully advocated for the change with the Lunar Precursor Robotic Program (LPRP) office. The change in impact crater was factored into LCROSS’ most recent Trajectory Correction Maneuver, TCM7.

During the last days of the mission, the LCROSS team will continue to refine the exact point of impact within Cabeus crater to avoid rough spots, and to maximize solar illumination of the debris plume and Earth observations.

Source: LCROSS

SMART-1 Releases Image of LCROSS Impact Site

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ESA’s SMART-1 team has released an image of the future impact site of NASA’s Lunar Crater Observation and Sensing Satellite (LCROSS). The SMART-1 team searched through their database to find images of Cabeus A, where LCROSS will search for water ice by making two impacts into this crater at the lunar south pole. The impacts are scheduled for 11:30 and 11:34 am UT on 9 October 2009. This image was taken four years ago by SMART-1, a spacecraft that ended its mission in 2006 by deliberately crashing to the Moon, similar to what LCROSS will do, hoping to exhume materials buried under the lunar surface, particularly water ice. “This is like gathering evidence for a Crash Scene Investigation, but before the action takes place,” said Bernard Foing, SMART-1 project scientist.

Cabeus A is permanently shadowed, so ice lying inside the crater could be protected from the Sun’s harsh rays. LCROSS will send the upper stage Centaur rocket crashing into Cabeus A and a shepherd spacecraft will fly into the plume of dust generated and measure its properties before making a second impact with the lunar surface. Astronomers will observe both impacts using ground and space-based telescopes. The SMART-1 spacecraft also concluded its mission with a controlled bouncing impact on 3 September 2006. The event was observed with ground-based telescopes and the flash from the impact was detected at infrared wavelengths.

Find out more about observing the LCROSS event here.

Foing and Bjoern Grieger, the liaison scientist for SMART-1’s AIMIE camera searched through SMART-1’s database for images of Cabeus A, taken four years ago at conditions where solar elevation and direction were similar to those of LCROSS impact. The SMART-1 image is at high resolution as the spacecraft was at its closest distance of 500 km from the South Pole.

“We are pleased to contribute these ESA SMART-1 observations of the LCROSS target site in order to help in the planning and interpretation of impact observations,” said Foing. “The coordination and exchange of information between lunar missions is an important step for future exploration of the Moon. Cooperation is vital if we are ever to see ‘villages’ of robotic landers and eventual lunar bases, as recommended by the International Lunar Exploration Working Group.”

Source: AlphaGalileo

LCROSS Anomaly Causes “Substantial” Fuel Loss

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The operations team for the Lunar Crater Observation and Sensing Satellite (LCROSS) mission has discovered the spacecraft experienced an anomaly, causing it to use up a substantial amount of its fuel. According to spacecraft data, the LCROSS Internal Reference Unit (IRU) experienced a fault. The IRU is a sensor used by the spacecraft’s attitude control system (ACS) to determine the orientation and trajectory of the spacecraft. The anomaly caused the spacecraft ACS to switch to the Star Tracker Assembly for spacecraft positional information and caused the spacecraft’s thruster to fire excessively, consuming a substantial amount of fuel. Initial estimates, however, indicate that the spacecraft still contains sufficient fuel to complete the full mission.

LCROSS is scheduled to impact the lunar south pole in early October.

The team discovered the problem during a communications pass with the spacecraft on August 22, 2009. Mission operations declared a ‘spacecraft emergency’ and were allocated additional communications time on the Deep Space Network. The team conducted procedures to mitigate the problem and were able to restart the IRU and reduce fuel consumption to a nominal level. Automatic operations procedures also were implemented to minimize the possibility of another IRU anomaly from occurring while the spacecraft is out of contact with the ground.

Thankfully, since the re-start of the IRU, the spacecraft has not experienced any additional problems.

The team continues to actively assess and mitigate the situation and is in contact with the manufacturers of the IRU and star tracker to investigate the root cause of the problems. Mission managers remain optimistic the LCROSS mission can reach its successful conclusion with projected impact at the lunar south pole currently set for 4:30 a.m. PDT on Oct. 9, 2009.

LCROSS launched with the Lunar Reconnaisance Orbiter on June 18, 2009. The main LCROSS mission objective is to confirm the presence or absence of water ice in a permanently shadowed region near a lunar pole. Learn more about LCROSS and LRO here.

Source: SpaceRef

LCROSS Sees Life on Earth

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The LCROSS spacecraft took a look back at Earth, and guess what it saw? Evidence of intelligence? Not so much. But it did see evidence of life. On Aug. 1, 2009, the LCROSS spacecraft took a gander at Earth to help calibrate and test its science payload. During the Earth observations, the spacecraft’s spectrometers were able to detect the signatures of the Earth’s water, ozone, methane, oxygen, carbon dioxide and possibly vegetation.

Phil Plait explained on Bad Astronomy that this spectrum covers part of the ultraviolet and visible range of light, and this type of observation with better instruments in the future could help us find life on other planets. Phil wrote. “You can see that LCROSS clearly detected ozone (O3) and water, which you might see on any old planet. But it also saw a feature that is from free oxygen (O2), something you don’t see just anywhere .… The only reason we have a lot of it in our air (more than 20% of the Earth’s atmosphere is O2) is because we have life in the form of plants.” Check out Phil’s post here.

LCROSS images of Earth. Credit: NASA
LCROSS images of Earth. Credit: NASA

The spacecraft also took these images of Earth, again, helping to refine camera exposure settings, check instrument pointing alignment, and check radiometric and wavelength calibrations.

LCROSS is in an elongated Earth orbit, and on course to impact the Moon’s south pole in October. From its current vantage point of 223,700 miles (360,000 km) from Earth, the LCROSS science team changed exposure and integration settings on the spacecraft’s infrared cameras and spectrometers and performed a crossing pattern, pushing the smaller fields of view of the spectrometers across the Earth’s disk. At this range, the Earth was approximately 2.2 degrees in diameter.

“The Earth-look was very successful,” said Tony Colaprete, LCROSS project scientist. “The instruments are all healthy and the science teams was able to collect additional data that will help refine our calibrations of the instruments.”

An additional Earth-look and a moon-look are scheduled for the remainder of the cruise phase of the mission.

Sources: NASA, Bad Astronomy

LRO Successfully In Lunar Orbit; LCROSS Provides Flyby Video

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The Lunar Reconnaissance Orbiter fired its braking thrusters for 40 minutes early today, successfully inserting the spacecraft into orbit around the Moon. Over the next several days, LRO’s instruments will be turned on and its orbit will be fine-tuned. Then LRO will begin its primary mission of mapping the lunar surface to find future landing sites and searching for resources that would make possible a permanent human presence on the moon. Also, early Tuesday, the companion mission Lunar Crater Observation and Sensing Satellite (LCROSS) sent back live video as it flew 9,000 km above the Moon, as it enters its elongated Earth orbit, which will bring it on course to impact the Moon’s south pole in October.

The two spacecraft reached the Moon four-and-a-half days after launch. LRO’s rocket firing began around 9:20 GMT (5:47 a.m. EDT) and ended at 10:27 GME (6:27 a.m. EDT), putting the spacecraft into an orbit tilted 30 degrees from the moon’s poles with a low point of 218 km (136 miles) and a high point of 3,000 km (1,926 miles). Over the next five days, additional rocket firings will put the spacecraft into the correct orbit for making its observations for the prime mission, which lasts a year — a polar orbit of about 31 miles, or 50 kilometers, the closest any spacecraft has orbited the moon.

Meanwhile, at 12:20 GMT (8:20 EDT) on Tuesday, LCROSS made a relatively close flyby of the Moon, sending back live streaming video. Watch the replay here.

LCROSS on its way to impact. Credit: NASA
LCROSS on its way to impact. Credit: NASA

LCROSS is now in its “cruise phase” and will be monitored by the mission operations team. During the flyby, the science team was able to obtain the data needed to focus and adjust the cameras and spectrometers correctly for impact.

LCROSS will never actually be lunar orbit, but is working its way to an elongated Earth orbit which will eventually bring it to the correct orientation for meeting up with the south pole of the Moon later this year. LCROSS will search for water ice on the moon by sending the spent upper-stage Centaur rocket to impact part of a polar crater in permanent shadows. The LCROSS spacecraft will fly into the plume of dust left by the impact and measure the properties before also colliding with the lunar surface.