Thursday, May 06, 2010

LRO Locates Lunokhod 1 Rover and its Laser Retroflector

The first successful robotic lunar rover, Lunokhod 1, landed on 17 November 1970. For the next ten months the rover was driven by operators in the Soviet Union, with the total distance traveled exceeding 10 km. A French-built laser reflector was aboard rover, but after Lunakhod 1 fell silent on September 14, 1971, the location of the rover and retroreflector was unknown.

Laser retroreflectors are used by ground-based telescopes to pulse of laser light to the Moon and back. The time for the return tells the position of the retroreflector to less than a centimeter. This allows scientist to measure the shape or the moon as it bulges due to tides, the wobble of the Moon as it rotates on its axis, and the motion of the of Moon on its orbit to within an accuracy of one millimeter, or about the thickness of a paperclip. Three reflectors are required to lock down the orientation of the moon – the retroreflectors left by the Apollo 11, 14, and 15 missions are still routinely used for these measurements. Additional retroreflectors would allow determination of different lunar parameters and enable grater precision. Occasionally the Soviet Lunokhod 2 reflector has been used for this information, though it is severely degraded relative to the Apollo reflectors.

Ground-based observers had occasionally looked for the Lunokhod 1 reflector over the last two years, but faced tall odds against finding it until recently. The breakthrough came last month when the high-resolution camera on NASA’s Lunar Reconnaissance Orbiter, or LRO, obtained images of the landing site. The camera team, led by Mark Robinson at Arizona State University, identified the rover as a sunlit speck on the image (see below) —miles from where teams had been searching. On April 22, Tom Murphy at UCSD and his team used the 3.5 meter telescope at the Apache Point Observatory in New Mexico to find the long lost Lunokhod 1 reflector and pinpoint its location to 10 meters on the surface and 2 cm distance from the earth. Finding the Lunokhod 1 allows for much better geodynamics and studies of the lunar interior.

Tuesday, February 16, 2010

Perigee Moon & Mars at Opposition

The last weekend of January 2010 promised two very special "close encounters" with our nearest neighbors. Planetary scientist Barbara Cohen at NASA's Marshall Space Flight Center answered your questions online about Mars at Opposition and the "largest" full moon of the year via a live Web chat on Friday, January 29, 2010 for over 90 minutes.

Here's the transcript. Enjoy!

(Moderator) Brooke: This is a moderated chat. If you haven't seen your question answered yet, please wait a moment as it is in the queue to be answered. Many thanks for your patience.

Barbara: Hi everyone. Tonight is a special night because there's a full moon and Mars is near Opposition.

Omnologos: Given the extraordinary success of Spirit and Opportunity why don't we just build and send more of them to explore more of the Mars surface?

Barbara: Every mission we send builds on the others. We have new science questions even as we learn from Spirit and opportunity. Our next mission Curiosity (Mars Science Laboratory) will have more instruments and be able to roam further.

Erin: Is there science or observations that can be done at an Opposition that can't be done during other times?

Barbara: At opposition, Mars is very bright, so you can see it with your own telescope, so you can observe it. We learn more about the planet's orbit.

TelescopPeMater55: Hello, I tried to look at mars with my telescope and I don't know how much magnification I need to see it can you tell me how much I need?

Barbara: You can see Mars with your naked eye. It's small, reddish-orange, and doesn't twinkle. If you have binoculars, you can see a disk. If you have a larger telescope, you might be able to see bright polar caps and dark dust.

Goody: How often do we have a perigee moon?

Barbara: About once a year. But it doesn't always exactly coincide with a full moon.

Michael_C.: Why doesn’t Mars “twinkle” like Sirius? Thank you.

Barbara: Because the planets are very close relative to stars. The light they give comes from a disk, so the light doesn't "twinkle."

(Moderator) Brooke: We're working on answering your questions right now. If you haven't seen your question answered yet, please wait a moment as it is in the queue to be answered. Many thanks for your patience.

Gabrielle: Is there a way to see it online, since it's very overcast where I live?

Barbara: There will be lot of amateur photos online.

gayle: Hi, I'm a student at an elementary school in Tampa. I was wondering why, if we knew that Mars would be so close to the moon tonight, didn't we schedule a trip to Mars when it wouldn't take so long to get there?

Barbara: Great question! We DO schedule Mars launches so they take advantage of when the Earth and Mars are close to each other. But it takes six months to get to Mars, so we have to launch six months in advance of when they line up together.

omnologos: The Moon is quite close indeed compared to Mars. If Ares is cancelled, can we expect at least some rovers to explore the more interesting bits we have only looked at from orbit?

Barbara: Curiosity (Mars Science Lab) is a rover the size of a VW. We're launching it in 2011, and it will explore more of Mars from the ground.

Erin: What do you learn about a planet's orbit from it coming closer during the Opposition?

Barbara: Planets orbits aren’t exactly circular. They're influenced by many objects: the Sun, its own moons, Jupiter, etc. It doesn't come closer during Opposition, but it's a special time when it's on the opposite side of the Earth as the Sun.

earthvisitor: Where will Mars be located in the sky in relation to the moon?

Barbara: Very near the moon. Looking at the moon with the naked eye, Mars will be within a "fist" of the moon tonight (Friday).

WIstormspotter: With spirit now stationary, is there a plan if while doing stationary exploration that it gets dislodged to start up and move again?

Barbara: No, Spirit is going to remain motionless during Martian winter because there's not enough solar power. In Martian spring, we may try to start moving it again.

Erin: Does the increased brightness of Mars at Opposition help observations from the large, professional observing telescopes?

Barbara: Yes, it does.

dwscott: What's the typical time gap between concept for a probe/rover and the time it lands on Mars? How far into that gap can the instrument(s) be modified to conduct an investigation inspired by results from existing probes/rovers?

Barbara: From concept to landing, it takes many years. :)

goody: How often does the moon and mars both have close encounters with the earth?

Barbara: The moon and Mars are both in elliptical orbits. The moon comes closest at a time called perigee, which happens once a month. For Mars, it gets to its closest point to the sun every two years.

Michael_C.: Is there a website similar to that provides sighting information for “natural” objects in the sky such as Mars? Thank you.

Barbara: Try Sky and Telescope's Web site.

robertbl22: What kind of binoculars (what power) do you recommend for viewing Mars?

Barbara: Any kind will work.

(Moderator) Brooke: We're working on answering your questions right now. If you haven't seen your question answered yet, please wait a moment as it is in the queue to be answered. Many thanks for your patience.

cosmo36: Hello, Is it possible for any unexplained Observation in 2003, on Earth? For instance perhaps unstable Magorstetic outer core disturbance that cause anything such as car malfunction?

Barbara: Opposition of the planets happens regularly. For Mars, it’s every two years. Mars isn't big enough to cause any disturbance on Earth.

(Moderator) Brooke: To those who want to see tracks of other near Earth objects, visit

gayle: How much difference in time does it take to get to Mars when the Earth and Mars aren't so close to each other?

Barbara: The fastest we can get there is about six months, but slowest could be years or more.

omnologos: Why not rovers on the Moon too?

Barbara: I wish! Many groups are proposing them, but NASA only has so much money. And we can't do everything. Hopefully, you'll see these in the future.

jjgravity: Will this conjunction happen with an eclipsed moon any time in the next few years?

Barbara: Great question. It's much rarer to happen with a lunar eclipse -- probably many years in between.

Erin: Regarding a question from gayle; might want to mention that (I think) the Curiosity mission was supposed to launch in time to take advantage of this opposition, but was delayed.

Barbara: Yes, that's right. There was a mission delay that caused us to miss the 2009 launch window, so next window is 2011.

Artemis: Are there other options besides the Aries project for space travel if this administration decides to kill the budget? It would be a shame if we couldn't explore the Moon or Mars.

Barbara: I can't speculate about future U.S. spaceflight plans. Right now we're staying focused on our current spacecraft such as LRO, MRO, and of course Spirit and Opportunity,

Ken: What is your opinion on the possibility of life on subsurface Mars, and would surface life be impossible due to radiation and sublimation of any water?

Barbara: We don't currently have any evidence for life on Mars. We think life depends on having liquid water and a benign radiation environment. So our Mars missions are looking for environments such as these where life might be able to live.

gwotty: Hi, Just joined & I'm happy to say after 2 weeks of total cloud, we have a FANTASTIC clear sky for viewing Mars & Moon tonight. I'm looking at it as we chat, out of my window, here in UK......

Barbara: Great -- good luck. If people have telescopes, they can take a look on any magnification. You can use binocular or the naked eye.

nasa: Will this be orange in colour?

Barbara: Yes, Mars is orange because the rocks are oxidized, making them red like rust.

robertbl22: How long will opposition last, or how long will it affect viewing?

Barbara: It's a moment in time, technically, but you can see it in that position for many days. In a year, it will be in its opposite configuration called conjunction, when it goes behind the sun.

One_Witchy_Woman: Can I take a picture of the moon and mars with a regular digital camera and have the halo show? Do I need something special?

Barbara: Yes, but the moon is so much brighter than Mars that it might not show up.

nasa: Will it look like a orange star next to the moon, when viewing with naked eyes?

Barbara: Yes, it will. But it won't twinkle like other stars.

revrosales: Humans have spent more than the six months for a trip to mars in the ISS and Mir already, correct?

Barbara: Oh yes. We learn a lot about how humans will be able to handle long spaceflight from our experience on the ISS. One difference is that the ISS is protected from radiation by Earth's magnetic field.

omnologos: Are the lessons learned from Spirit getting stuck being applied to Curiosity or is it too late?

Barbara: Yes, many lessons learned about the nature of the Martian surface, and the mechanics of roving. But Curiosity is probably not going to the same place, so we'll have more to learn when Curiosity arrives.

cbekiaris: what is your favorite color??!

Barbara: Magenta. :)

(Moderator) Brooke: This is a moderated chat. If you haven't seen your question answered yet, please wait a moment as it is in the queue to be answered. Many thanks for your patience.

Artemis: How long does it take to reach Mars with conventional spacecraft, and how long are the Martian seasons?

Barbara: Six months to arrive with current spacecraft. Martian year is about two years, so each Martian season is about six months.

llama1: Does NASA have any tentative schedule for sending people to Mars?

Barbara: No, not yet.

ZhaneDoe: Explain Perigee.

Barbara: The Moon's orbit around the Earth isn't exactly a circle, but an ellipse or oval. Earth isn't in the center. One end of the oval is far from Earth, one is close. When the moon is at the far end, it's called apogee. Near end is perigee. The orbit is once a month.

nasa: Can we see the pictures of mars as of today's event?

Barbara: There will be images online at various Web sites.

TaviGreiner: Read today that the Full Moon 15% of the Sun's light, compared to just 8% the day before or after - that's a 50% difference for not really much difference in illumination. Are those numbers accurate?

Barbara: I don't know if the exact numbers are accurate, but yes, the combination of the full moon and perigee make this full moon very bright compared to other full moons this year.

greg_p10: Can bacon be cooked in outer space? I need to settle a bet....

Barbara: Yes. If it couldn't, I wouldn't want to go! J

yummynuga: Will I be able to see Mars in the night sky?

Barbara: Yes, very close to the full moon. You must have clear skies.

Artemis: Will Mars be relatively visible to the naked eye this evening?

Barbara: Yes, will look like an orange "star" that doesn't twinkle.

quarkspin: Why use orbiters, landers, and rovers? Are there advantages to each?

Barbara: There are advantages to each kind of mission. Orbiters give you a global view of the planet. Rovers allow you to explore a small area in great detail. Landers allow you to do long-term observations in the same place.

goody: Question is there really a ring around earth made up of space junk??

Barbara: Yes, there is a lot of space junk around the Earth. NASA monitors it locations to make sure our satellites and the ISS have a clear orbital path.

WIstormspotter: Do you guys get a good laugh every time that article gets thrown out on the internet about Mars being so close to the earth it will be as large as a full moon?

Barbara: Yes, we do. :) Mars is not ever going to appear as large as the moon.

ZhaneDoe: How long is Mars away from earth?

Barbara: About 70 million miles.

cbekiaris: But seriously, is there any way to view Mars from Illinois at night? if so what kind of telescope would you recommend? And is there any way to view the moon and Mars at the same time?

Barbara: If it's not cloudy you can see Mars near the full moon tonight. To the naked eye, it will look like a small orange dot. With binoculars or telescope, you can see the disk.

Azorean: Hi all, Portugal here! Without the magnetosphere protection, it's not dangerous to travel between Earth and Mars?

Barbara: Yes. One of the primary risks in traveling between the Earth and Mars will be radiation. Humans and spacecraft will both need to be protected.

Clover: Is there a set date for sending another probe to explore Mars?

Barbara: Yes, Curiosity will launch in 2011.

julieta: Which features/aspects of the moon can viewers see today that can't be seen in another time of the year?

Barbara: It's about the same for each full moon, just brighter tonight.

Erin: Does having the Moon and Mars both being at least a little bit closer to Earth (compared to other times) affect tides?

Barbara: Great question. Yes, the closer the moon, the higher the tides. Perigee moon causes higher than normal tides by a tiny bit (millimeters). Mars has no measurable effect on Earth tides.

ZhaneDoe: Was water really found on the moon?

Barbara: Heck yeah! :) LCROSS kicked up a big cloud that had gallons of water in it.

Michael_C.: It’s cool that this event is taking place on the NASA Day Of Remembrance. A fitting tribute!

Barbara: Yes, all of us at NASA are remembering our lost comrades.

TaviGreiner: Will future human missions to Mars pose the same/similar dust issues that we faced with the Moon?

Barbara: Yes, but no. :) Mars is a dusty place, but Mars dust is very different than moon dust. Mars dust is rounded, moon dust is jagged. Mars dust is oxidized like rust, so it may react with metal. We'll have to deal with Mars dust in a different way.

omnologos: Is there a website with all scheduled and proposed future Mars missions?

Barbara: Yes, visit

(Moderator) Brooke: Learn more about past, present, and future Mars missions at

Mitch: I'm a retired NASA Expert and have heard rumor of a space rover to launch for Jupiter in 2012?

Barbara: Jupiter has no solid surface, so rovers won't work. :) But, NASA is sending a probe called JUNO in a few years.

yummynuga: How big is the moon?

Barbara: About 2,000 miles in diameter.

(Moderator)Brooke: Learn more about NASA's JUNO mission to Jupiter at

Sunstreaked: What exactly does a planetary scientist do?

Barbara: Web chats! :) Seriously, I study rocks from other planets to learn about their geology. We get the rocks here from missions like Apollo, or delivered to us as meteorites.

(Moderator) Brooke: We're working on answering your questions right now. If you haven't seen your question answered yet, please wait a moment as it is in the queue to be answered. Many thanks for your patience.

Yellowstone: Why is Mars the only red planet (oxidized)?

Barbara: It's not the only red planet. Jupiter is kind of red, and so is Mercury because oxygen has reacted to minerals on those planets as well.

johnpv: Will Curiosity investigate about the methane too, or is that a mission for MAVEN and later?

Barbara: I believe there's a joint ESA/NASA mission called Mars Trace Gas Explorer that will specifically investigate methane and other atmospheric gases.

vca186: Since Mars is closer to Earth than usual, what effect does its gravity have on Earth’s orbit?

Barbara: No measurable effect.

goody: Is there any possibility of another planet that can support life like Earth??

Barbara: Definitely. What we need to support life are air to breathe, water, shelter, and sunlight -- and solid surface. Other planets may not have the natural perfect combination, but we can bring some things with us or create them there.

Mitch: Will the Earth and Mars ever collide? When is that projected to be?

Barbara: No, they won't collide. The orbits are stable even if they're not perfect circles.

guest: Where will Mars be in relation to the Moon tonight?

Barbara: Within about a "fist" of the moon, to the naked eye.

TaviGreiner: For current Mars viewing, is one hemisphere more prominent than the other (N vs. S)?

Barbara: Only very slightly more visible in the northern hemisphere.

Erin: What would your reactions be if life was found on Mars?

Barbara: I think it would be one of the most interesting discoveries of all time.

(Moderator) Brooke: Learn more about the MAVEN mission mentioned earlier at:

Joyce: When is man going to Mars?

Barbara: We don't know yet. NASA doesn't have a current date.

(Moderator) Brooke: This is a moderated chat. If you haven't seen your question answered yet, please wait a moment as it is in the queue to be answered. Many thanks for your patience.

SpaceChimp16: I see the moon, full and clear and a small orange-y star looking thing on the top left from the moon, how big will Mars get? I am 16 and I'm really excited!!

Barbara: Yes! :) Mars looks like small star with the naked eye. It won't be very large.

planewatchers: Should we expect to see a halo with this evening’s event as we did last night?

Barbara: The halo you saw is probably related to your local weather. You might have ice crystals in your local atmosphere.

Erin: What originally got you interested in Planetary Science?

Barbara: I took a class in college about geology and how you can "read" rocks to understand the planet. I thought it would be cool to read the history of a planet that I couldn't step on.

werkbert: Hi. Q? If the moon is moving away from Earth (1 inch a yr), did the moon look any different in the sky 1 bil or 2 bil yrs ago vs. today and by what % bigger?

Barbara: It is moving away from the Earth, so it did appear bigger, but we don't really know where it was 3 billion years ago. Scientists are working on models to understand this.

BEA: When can I see the full moon the best?

Barbara: Tonight is the full moon. It will look nearly full tomorrow night.

(Moderator) Brooke: We're working on answering your questions right now. If you haven't seen your question answered yet, please wait a moment as it is in the queue to be answered. Many thanks for your patience.

Erin: What classes in school or experiences do you feel prepared you for work as a Planetary Scientist?

Barbara: All of them. :) Math, science, writing -- I do a lot of writing. Problem-solving and critical thinking.

TaviGreiner: Why do planets not twinkle, as opposed to the stars that do?

Barbara: Because they're closer to Earth than stars, they aren't perfect point sources of lights. They're disks.

Michael_C.: Are Phobos and/or Deimos ever closer to the Earth than Mars? Thank you.

Barbara: No, very close to Mars.

ve3cxb: Regarding the electron microscope image of the alleged bacterial-like life form found in the Martian meteorite several years ago that caused all the excitement. I'm a professional electron microscopist so as soon as I saw that photo I knew it wasn't a life form. However I never did hear what you folks determined it to be.

Barbara: Yes, they were too small to be life forms as we know life, so probably are minerals.

the11ama: Would a spacecraft sending people to mars contain a rotating section for artificial gravity?

Barbara: We don't know how to solve that problem yet. We use research on ISS to determine long-term effects of microgravity on humans.

guest: Does NASA have any tentative schedule for returning people to the Moon?

Barbara: I can't speculate on the future of U.S. spaceflight plans. However, here at Marshall are working on plans to send robotic missions to the moon for science.

omnologos: What do you think of the proposal of sending people to Mars on one-way tickets? It'd make a great site for a retirement home!

Barbara: NASA isn't in the business of sending humans to places where we can't bring them home safely.

WIstormspotter: Will Mars transit the moon at all tonight or will they basically be moving in sync with each other?

Barbara: The moon occulted -- passed in front of -- Mars during conjunction in 2007 but won't this year.

CollinDue: Will the nearness of MARS cause a shift in the tide, or change the ocean's PULL in any way?

Barbara: No, Mars is too small to have measureable effect on the tides.

guest: Would it be to the left, right, above or below the full Moon tonight?

Barbara: It's to the west, but what you see will depend on where you're observing from tonight. Check the Sky and Telescope Web page.

CollinDue: Does NASA have any regulation/restrictions in regards to leaving Spacecraft debris on MARS?

Barbara: Yes. We have a policy called Planetary Protection that governs our decisions in sending and leaving spacecraft.

Erin: How do you feel about the argument of robotic versus human missions to the Moon and Mars?

Barbara: Good question. Robotic and human missions are complementary to each other. You need both to effectively explore the solar system.

revrosales: Barbara, I recall reading about a training simulation in Russia that involved six months of isolation for the "crew", and that there would be more simulations in the near future. Any idea when further simulations are scheduled to run? –Thanks

Barbara: Sorry, I don't know.

Erin: What are your thoughts on the private companies aiming for landings on the Moon?

Barbara: The Google lunar X-Prize projects are very exciting. I'd love to see a whole fleet of rovers and landers on the moon.

hello: Are you posting the pics on NASA website?

Barbara: No, but many other sites will be.

Erin: Yes, bacon can be cooked in space. Heat works the same way there as here. But remember, there's nothing to hold it to a frying pan! =D

Barbara: Agreed. :) Maybe you could spin the frying pan really quickly.

LuDean: How many rover robots are currently operating on Mars?

Barbara: Two: Spirit and Opportunity. Both are still going after six years.

TaviGreiner: Why does the Full Moon look so much larger against the horizon than in the sky? Is this an illusion created by our atmosphere, the curvature of our Earth, or simply the perspective of foreground objects? I've seen explanations for all three.

Barbara: You're right, an illusion. The perspective of foreground objects is by far the greatest contributor.

Erin: Would you rather see humans first go to the Moon or to Mars?

Barbara: It's a personal opinion, but I'd like to see humans go to the Moon first.

jmorcone: Why is this the fullest moon of the year? What makes it bigger than others... is it the proximity to Earth?

Barbara: Yes, proximity at perigee makes it the biggest full moon of the year.

Richard_Stember: In the announcement that the MER Spirit is now a stationary observatory it was mentioned that it be used to determine if Mars has a solid of liquid core. How will this be done? Measuring wobbles in its orbit?

Barbara: Yes, this technique is very much like the laser ranging arrays on the moon. The position of the spacecraft when stationary tells you how the planet wobbles around its axis, which is related to its internal structure.

CollinDue: Would Mars have a sky if we added more water on the surface?

Barbara: I think you're asking about an atmosphere? Yes, if Mars were warmer and there were liquid water there would be thicker atmosphere and the sky would be bluer.

the11ama: How different would Mars look tonight between someone on the ground and someone on the ISS?

Barbara: Almost no difference because Mars is so far away.

TaviGreiner: Are meteoroids / asteroids of much concern when sending crafts to Mars?

Barbara: Micrometeorites are a great concern. They are everywhere and we have to make spacecraft able to withstand them.

earthvisitor: With the newest announcements of cuts to NASA, will Curiosity still launch as scheduled or is it in danger?

Barbara: Just can't speculate right now. Sorry!

DankNugs: Is the moon made of cheese?

Barbara: No. :) It’s made of rocks like Earth and other planets.

Vladimir: If there’s water on mars does that mean we can live there if we actually go to it?

Barbara: It would certainly help!

cbekiaris: I want to say thank you for answering my question, I’m in my high school astronomy class right now working on a worksheet (you don’t need to answer this or anything) but for someone at NASA to answer my question is really awesome! Also all the silly questions you are getting like the one about bacon in space, they are all from kids in my class so on behalf of Mundelein High School Astronomy class I want to say thank you for amusing us. I hope you have a nice day!

Barbara: My pleasure. Now get back to work! :)

Vladimir: How would it take us to get to Mars if we flew there?

Barbara: Six months at the best.

omnologos: Mars has no effect on Earth...has the Earth any effect on Mars?

Barbara: No, no measurable effect. The biggest effects on Mars are the Sun and Jupiter.

LuDean: Would a manned mission to Mars potentially launch from a base on the Moon?

Barbara: Good question. Some people think it would be helpful to launch from the moon because the moon's gravity is lower than Earth, but at this point we build everything on Earth. So we'd have to launch from Earth to the moon first, which probably negates savings now.

Karl_Hovekamp: Could it be there is liquid water on Mars periodically (in millions of years)?

Barbara: You may have heard that Mars has what we call "chaotic obliquity" which means over many millions of years, the seasons aren't constant and could be warmer. Maybe warm enough to have liquid water. Missions are looking for evidence of that liquid water, even though it's not there now.

(Moderator) Brooke: We've got time to answer just a few more questions.

Erin: Was there any modifications proposed to be made to Curiosity to protect it, when the Martian dust devils were discovered by Spirit and Oppy?

Barbara: We already knew that there's dust in the Martian atmosphere. Curiosity won't rely on solar panel for power like Spirit and Opportunity do.

DankNugs: Are there rocks on other planets that look like some from Earth or the moon?

Barbara: Do you mean meteorites? Spirit and Opportunity have found rocks on Mars that come from the asteroid belt, but so far none that we think came from the Earth or the moon.

WIstormspotter: Now that the LCROSS mission had found that there is water on the moon, Is there anything else that is worth looking for on the moon?

Barbara: Sure. Resources on the moon are things like light, water, and the oxygen found in the rocks.

(Moderator) Brooke: We've only got time for 2 more questions.

TaviGreiner: We've returned dust from a comet - why have we not returned samples from asteroids or Mars? Do on-site investigations with rovers tell us as much as would a sample return?

Barbara: Sample return is an important part of space exploration. We can learn more about the rocks in our labs and do duplicate analysis. Sample return missions are proposed for Mars and the moon and hopefully will happen soon.

adam: Why can liquid water not exist on the surface of Mars for extended periods of time?

Barbara: To have liquid water, you have to have warmth and pressure. Mars is very cold and has a very thin atmosphere, so water isn't stable as a liquid. We've seen it exist as a solid.

Bill_Macfarlane: Several years ago, Mars was at it closest in many thousands of years. What is the difference in distance now compared to back then?

Barbara: presently about twice as far away during this conjunction as during the 2003 conjunction, when it was closest

(Moderator) Brooke: Thanks to all of you for all the great questions, and thanks to our guest scientist, Barbara Cohen! Our Mars Opposition chat is now closed, but you can find more information at Check back on Monday for a posted transcript of today’s chat. Have a great weekend.

Saturday, September 12, 2009

A Day at Desert-RATS

I spent an amazing couple of weeks in northern Arizona with the Desert-RATS team this year. The Desert RATS field test activity coordinates individual science, technology and operations development efforts into a field test demonstration under representative (analog) planetary surface terrain conditions. The purpose of the RATS effort is to drive out preliminary exploration operational concepts for EVA system requirements by providing hands-on experience with simulated planetary surface exploration extravehicular activity (EVA) hardware and procedures. The 2009 Desert RATS activity had the first significant integration of science into the overall operational scenario by providing geological context and protocols both prior to and during surface activities at the Black Point Lava Flow. We had one half of an operations trailer for the SSR. Each day, we had eight backroom functions and two field observers out in the real world looking over the crew’s shoulders. I got to rotate though field observing, the three “expert” stations (Petrography, GigaPan, and Structures), and SciCom, who communicated directly with the crew during science operations. August 29/30 were one-day traverses by Crew B (Andy Thomas and Jake Bleacher), and September 2-9 were geologic traverses during a 14-day test by Crew A (Mike Gernhard and Brent Garry). I was an SSR observer on Sept. 3 and here’s the play-by-play. Keep up with their photos here!

7:45 today I’ll try to keep up a stream from the science backroom @DESERT_RATS. It's a very busy place but today I am a floater/observer.
7:56 our day has already started with a tagup at 7 am and everyone is busily preparing for wheels rolling at 8:14.
8:02 the astronauts are in the rover and the science backroom is starting the daily pretraverse briefing. it's in powerpoint, of course :/
8:07 Jose is PI today; he planned the traverse and science objectives, and is explaining them to the crew.
8:10 the science prep purposefully used only bw aerial imaging. It's up to the crew travers to help us understand the area and its geology
8:18 Lunar Electric Rover (LER) is rolling
8:40 the crew has reached station 1 and are preparing for egress; backroom is using LER cameras to see the surroundings
8:45 EV1 (Jake) is in his suit and backroom gave him a set of targets to sample. it's a collaboration between what we want and what he can get.
8:55 EV2 (Andy) is in the LER feeding images and descriptions to us
9:05 nearing the end of the 25 minute EVA; we bagged 2 basalt rocks and a soil.
9:08 and a bonus float rock from EV2. thanks Jake!
9:10 phew, that was frantic. backroom captures images, documents samples, types observations, keeps time, and reassesses on the fly.
9:16 on the short drive to the next site, EV2 is hanging out in the suit port
9:22 we're getting a narrative of site 2 environs and preparing for a rapid Gigapan acquisition
9:26 when crew goes out of LER, it's egress. when they hang out in the back and step off, it's offgress. Offgress?
9:30 now at site 2. we only have a single comm channel and right now it's cacophonous.
9:31 science objectives at site 2; contact between lava flow and sandstone; sample sandstones.
9:53 we've accumulated 20 mins negative time, so site 3 will be drive-by rather than EVA
9:59 the flexible shroud that covers the suit ports is called the Cabana, and you *know* that always triggers Barry Manilow in my mind.
10:38 pays to have an itchy trigger finger: snuck in a quick gigapan when the crew stopped to answer some medical metrics
10:40 I walked out of the trailer and nearly bumped into the ATHLETE. Yowza.
10:45 passing stations 4 and 5, small mesas of the beautiful red Moenkopi formation
11:04 the LER navigates on GPS and Google Earth. Good thing we've also got Google Moon!
11:08 large brownish quadrupeds surrounded by a large fence-like formation on the left
11:20 driving over shale and brush to the next visible outcrop. science backroom is catching up and filling out metrics (ugh)
11:32 oooh, someone brought in otter pops for the backroom! :)
11:33 found station 6 via combination of K10 reconnaissance knowledge and realtime navigation
11:39 preparing for dual crew egress. station 6 goals: sample lava flow and sandstone; compare with previous site stratigraphy
12:11 one of the reasons I am here is to understand ops differences between Apollo and MER. they are as big as I expected!
12:18 lunchtime!!
12:55 science backroom took the lunchbreak to modify the traverse plans for the afternoon. No science is worth staying until 9 pm :)
13:01 psyched to see @marsrovergirl here @DESERT_RATS; she's putting ATHLETE thru its paces
13:34 hooray! BubbleCam is functional, capturing images right below the LER nose.
13:50 heading on a northern spur where we may lose comm; briefing the team on EVA activities without us in the loop
13:58 passing old tracks, footprints, cowpatties. If we could find them on Mars, we'd be golden :)
14:04 hooeee our science backroom trailer is a'rockin in the fierce wind outside
14:07 oh and also, tons of fun to Dust_devil_WATCH
14:23 ok, finally to station 8. science goals: describe and sample every unit. modest, we know.
14:35 during EVAs, we get video from cameras on the crew's halmets and shoulders, and we get to control the rover cameras to zoom in on outcrops.
15:04 extremely successful station 8 with 10 samples in 25 minutes! rocks : geologists :: donuts : Homer Simpson.
15:07 gorgeous photo of station 8 from @DESERT_RATS
15:36 we're making extensive use of GigaPan. 360 color coverage at 2 elevations in 1.93 minutes. But no near IR channels.
15:41 driving thru soft soils in a wash; soil is caking on the wheels. But its shallow compared with LER's big fat tires (mmm cake and a Fat Tire)
16:00 team is doing dome driveby geology on the way home. conglomerates, high albedo depressions, mesas oh my
16:55 made good time on the way back so were able to squeeze in one more EVA. Crew and ops are both feeling good about the day!
16:56 pics from the last EVA of the day
17:31 LER is back in camp; science team is discussing and preparing debrief
17:42 We get 15 minutes with the crew after Human Factors gets their info.
18:17 Great job everyone. it was a long day but we all learned a LOT :)

Tuesday, September 01, 2009

Decadal Survey in 140 characters or less

I'm a member of the Inner Planets panel of the Planetary Science Decadal Survey. We're responsible for representing the communities who study Mercury, Venus, and the Moon. We recently held our first panel meeting in Washington DC and I tried to twitter along. The tweets were crossposted to Facebook and generated a lot of interesting discussion too! But if you aren't a fan of those two sites, here's the running narrative.

August 26th

6:21 AM I'm headed to DC for a meeting of the Inner Planets panel of the Decadal Survey. Hoping to twitter it! Stay tuned.

1:16 PM kicking off the closed session with boring but necessary logistics.

1:24 PM I wonder how many mission statements you can sing to the tune of the Preamble to the Constitution. Well, at least one, the NAS.

1:30 PM the National Academy of Science started around he civil war; early studies included "how to keep soldiers from drinking too much whiskey"

1:37 PM in order of descending age: National Academy of Sciences > smackwell > Space Studies Board > NASA > me

2:27 PM bias and conflict of interest, or, True Confessions, Science Edition.

2:44 PM wow, what an impressive group of people assembled in this room.

3:07 PM I'll never, ever be sick of listening to Steve Squyres

3:52 PM open session (Ellen says, "truly open") beginning now. live webcast at

4:14 PM Only planetary bodies without current or planned missions: Uranus and Neptune. Good time to be a planetary scientist!

4:35 PM Discovery draft AO is signed and expected by FY09; AO by CY09; cost cap $425M excluding LV and ASRG provided as GFE. LOL and BYOB.

4:53 PM How is community input is shaping up for lunar science in white papers for the Decadal Survey?

5:31 PM was the last decadal survey *too* detailed in specifying what missions were expected to accomplish? or does detail help scope the issues?

5:46 PM open session is over. we're breaking before a working dinner. predinner: small group to get the creative juices flowing ;)

August 27

8:07 AM ILN is first on the agenda today; nerves starting to set in.

8:09 AM Inner Planets webcast and telecon number are listed on our agenda:

10:08 AM Sean Solomon is talking about Mercury now. Mercury is cool (hot). Also Sean is wearing an excellent abstract-modern-planetary tie.

10:21 AM Great acronym for a Mercury mission: WGBMWGMWDPD! (We're Going Back to Mercury and We're Going to Map the Whole Damn Planet Dammit!)

10:34 AM huh, Mercury's spectra are pretty flat - not much ability to pull out mineralogy.

10:40 AM Post-MESSENGER, Bepi-Columbo ESA/JAXA mission with dual coplanar orbiters to Mercury in 2014. What should be next? Landers or sample return?

11:35 AM ahhhh, for days spent lounging by warm salty oceans on Venus.

1:04 PM 2 really awesome lunch discussions with 2 of my science idols, wow, I am lucky to be here.

1:08 PM Sue Smrekar: Venus challenges our ideas of how a terrestrial planet "should" work.

1:54 PM Jim Head on future science for Moon & Mars: the future is not in plastics, but plasticity - that is, adaptability and opportunity

2:22 PM Did Carl Sagan really call the Moon a burned-out cinder? Wow. That's harsh.

2:37 PM Venus: Earth's twin? Earth's sister? Earth's future self? Some other relation?

2:42 PM Jim Head: Could global resurfacing (Venus) happen here? If I were in charge of Earth, I'd worry about it; fortunately for everyone I'm not.

3:34 PM For the rest of the afternoon, we'll be talking about JPL, APL, and GSFC support for mission studies we'll be exploring.

4:14 PM I have a new role model: Ellen Stofan. She's brilliant, organized, and wears pink.

4:36 PM GSFC on LRO: "Even though this mission went to the Moon, it really was very much like a planetary mission"

5:18 PM thank you thank you thank you GSFC and APL presenters for making up schedule time.

August 29

8:15 AM Inner Planets starting in 15 minutes; join us using info here

8:17 AM Sample Return: Part of a balanced and nutritious planetary mission portfolio

8:44 AM Sample return missions include more than just the mission itself - curation and laboratory facilities are crucial (but legacy)

8:55 AM atmospheric sample return from Venus?

9:39 AM lunar meteorites = poor man's sample return mission

10:12 AM Closed session until lunch - discussing all the work we have in front of us!

10:25 AM Everyone should be writing or endorsing White Papers - it's your way of letting us know what's important to you!!

11:37 AM How well did NASA follow the recommendations of the last Planetary Decadal Survey?

12:59 PM White papers *must* be submitted via the SSB web page by September 15!

3:27 PM this afternoon: DCA-PHX, shuttle to Flagstaff. Tomorrow I join @DESERT_RATS; *so* psyched!

Wednesday, August 19, 2009

ILN update

Several of you have asked for a mission status for the ILN. Things have been in flux for the last couple of weeks but look like they are settling out so it's a good time to update you, and also to ask for your help.

The project has been conducting trade studies in response to HQ's changing directions regarding this mission, finally presenting two alternatives to HQ: a 2-node solar-battery option and a 4-node ASRG option. Neither one fits under the original $200M cost cap (unsurprisingly). Therefore OMB initiated a review of the project to understand the design and cost and to define "alternatives." The review went well and found that the cost and schedule for the mission concepts were in-family. You can see a summary of the ILN project to date in my NLSI talk.

However, in the current budget, SMD cannot afford the ILN. So for FY10, HQ has chosen to allocate the project $3.7M and direct it to become the Lunar Quest lander project office, who will conduct risk-reduction activities on a generic ILN-class lander. SMD's current stance is to wait for the results of the Decadal Survey to decide what direction to take for a lunar lander mission, which may or may not be ILN, depending on the Decadal prioritization.

If you think the ILN idea is still a good one, I urge you to sign on to Clive Neal's white paper to the Decadal Survey about the importance of a lunar geophysical network. Having an interested and enthusiastic community backing will help the ILN achieve a high prioritization in the Decadal Survey.

Friday, July 10, 2009

The Moon is a planet too

The Moon would totally be its own planet if it weren't orbiting the Earth. Also, it deserves its own capital letter. However, style-conforming blog post follows, from the LRO and LCROSS blog site. Enjoy!

Lunar scientist Barbara Cohen explains how our moon functions very much like a planet.

You've all probably heard about the International Astronomical Union (IAU) decision to define a planet -- probably because it clarified that there is a big belt of icy objects out beyond the orbit of Neptune, and we now know that Pluto is one of thousands of them. The IAU definition also excludes moons from being planets. But did you know our moon functions like a planet? It has a lot to teach us about how planets form and evolve.

Solar system rendering of the eight planets. (Image credit: Koolang Astronomical Observatory and Science Display Center)

Like the Earth, our moon has a crust, a mantle and a core. These interior layers we think are present on most planets, even if the crust is made of rock or ice. Mars probably has a crust, mantle, and core, and so do Venus and Mercury. The rocks we brought back from the moon from the Apollo missions helped us learn that this process of forming internal layers, or differentiation, is a common process on all planets. So when the moon formed, it formed like a planet.

Another hallmark of planets is that they have active geology. The big, dark splotches you see on the moon’s surface are lava flows. Yes, there were active volcanoes on the moon. There aren’t any volcanic cones, because the lava was very fluid and flowed out through cracks and into low-lying areas. The Apollo samples contain small beads of volcanic glass that tell us there were giant fire-fountains on the moon too. Though volcanic activity on the moon ended about 3 billion years ago, the Apollo missions picked up thousands of earthquakes on the moon, or moonquakes. Moonquakes tell us that the moon is not geologically dead. It's still acting like a planet today.

Hawaii Volcanoes National Park. (Image credit: Photo Credit: National Park Service)

My favorite part about planets is their impact craters, formed when asteroids or comets whizz into our part of space and collide. When you look at the moon, you can see that it preserves many impact craters on it for researchers like me to study. Did you know that all the craters you see on the moon (and there are hundreds of thousands of them!) had counterparts on the Earth at one point? We don't see many impact craters on Earth today because the Earth's crust continually renews itself and erases old rocks and formations. No one rock on Earth is older than 4 billion years. The Earth definitely got beat up by impacts from comets and asteroids in its past -- and that record is preserved for us to study on the moon.

For me, the best thing about the moon is that it may not be defined as a planet, but it definitely acts like one. Studying the moon allows us to learn about how all planets work. And because the moon is ancient, it's like a time capsule back into the early days of our solar system. But, I also love that the moon looks so beautiful reflecting sunlight to us on dark nights and I can't wait to get more information from our two lunar missions. Go LRO and LCROSS!

Saturday, July 04, 2009

Uranium on the Moon?

A spate of recent articles is covering the presentation of the first orbital uranium maps of the lunar surface, like this article in SpaceRef (the original work was presented by the Kaguya GRS team, including my former colleague Bob Reedy, at this year's LPSC). Some of these articles suggest that the new maps mean "nuclear power plants could be built on the moon, or even that Earth's satellite could serve as a mining source for uranium needed back home." Just how significant is this new finding?

The media is spinning this as "uranium discovered on the Moon," but in fact we've known about uranium in lunar samples since the return of the Apollo 11 samples in 1968. When the lunar samples came back, there was a phase in them that was highly enriched in potassium (K), rare earth elements (REE) and phosphorus (P), among other freaky elements. This material was nicknamed KREEP, and the moniker stuck. Lunar rocks are known to contain hundreds of ppb uranium, and some minerals up to 4000 ppm. The natural decay of uranium to He and lead is a commonly-used dating scheme for lunar rock ages.

So what is this KREEP layer, anyway? During planetary formation, minerals crystallize and sink or float depending on their density. That gives early planets a layered internal structure - the crust, mantle, and core. However, uranium (along with other similar elements like Th, K, etc.) doesn't have an affinity for fitting into most common minerals. They are called "incompatible" elements for being incompatible with mineral structures. As the Moon crystallized, these elements stayed in a liquid layer and wound up being squeezed between the crust and mantle. This layer contains all those incompatible elements, the leftovers of differentiation.

After the Moon formed its layered structure, giant impacts dug below the crust and scattered the KREEP layer over the surface, mostly on the nearside where the crust is thin. So when you look at a thorium map of the Moon, you're looking at the surface expression of KREEP, including all those incompatible elements like U.

The real news story here isn't that there is uranium on the Moon, but that it's the first time U has been directly detected from orbit. The natural decay of uranium emits characteristic gamma rays, which can be measured from orbit by very sensitive instrumentation. Because U is only present in trace amounts, it's a truly amazing accomplishment for the Kaguya GRS to measure these gamma rays from orbit. The new information will allow us to understand the distribution of U on the surface, which gives us insight into how the KREEP layer was dug up and flung about. Congratulations to the Kaguya GRS team!