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10-15-08

Scouting the Moon (III)

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Credits: NASA

 

In the previous two posts in this series, we presented NASA’s Lunar Reconnaissance Orbiter (LRO) and the Chandrayaan-1 mission, which was designed and developed by ISRO. These two missions are typical lunar scouting missions: the spacecraft with onboard remote-sensing instruments will orbit the Moon, collect scientific data, and relay it back to Earth.

 

NASA will launch another lunar scouting spacecraft on the same Atlas V rocket with LRO: the Lunar Crater Observation and Sensing Satellite (LCROSS). This mission is not a typical scouting mission and we will see why in this post.

 

In 1999, a precursor of LRO and LCROSS called the Lunar Prospector detected traces of concentrated hydrogen at the lunar poles. As a result, the LCROSS mission’s main goal is to confirm the presence or absence of water in a permanently shadowed crater near a lunar polar region. At the present time, landing a probe on the lunar surface and performing excavations or drilling would be very expensive. A less expensive solution for the LCROSS mission is to use a kinetic impactor to excavate a crater on the surface of the Moon.

 

Credits: NASA

 

After the launch, LRO will separate from LCROSS, and continue on a solo journey to the Moon. LCROSS will remain attached to the Centaur upper stage of the Atlas V launch system.

 

While LRO will follow a trajectory that will place it in a polar lunar orbit, LCROSS will execute a flyby of the Moon, and use an elongated Earth orbit to position itself on an impact trajectory. During this time, the LCROSS mission team will perform instrument calibration and corrections for the impact trajectory. The target of the impact will be the lunar south pole.

 

Seven minutes before the impact, LCROSS will separate from Centaur. The Centaur will be used as a kinetic impactor. Having a mass of approximately 2,200 kg, on impact, it will excavate a crater 20 meters wide and 3 meters deep. According to NASA scientists, more than 250 tons of lunar material will be propelled into space.

 

Credits: NASA

 

LCROSS will then fly through the debris of the previous impact. The instruments onboard LCROSS will collect scientific data and the spacecraft will relay it back to Earth. LCROSS will end its mission four minutes after the Centaur impact by creating its own impact crater on the lunar surface. The last S in LCROSS should stand for Smasher instead of Satellite considering the final act of the mission!

 

The scientific instruments onboard LCROSS cover a wide spectrum: two near-infrared spectrometers, a visible light spectrometer, two mid-infrared cameras, two near-infrared cameras, a visible camera, and a visible radiometer. The instruments can detect traces of organics, hydrocarbons, hydrated minerals, water ice, and water vapor. More details about the LCROSS scientific payload can be found on LCROSS mission page.

 

I wonder to what extent the debris caused by the impact of Centaur and LCROSS will interfere with the scientific instruments onboard LRO and Chandrayaan-1. Both LRO and Chandrayaan-1 will be orbiting the Moon on polar orbits at that time.

 

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10-8-08

Scouting the Moon (II)

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We presented in a previous post the Lunar Reconnaissance Orbiter (LRO) mission. The goals of the LRO mission are to map the lunar resources and to create a detailed 3D map of the lunar surface in preparation for future NASA missions to the Moon. However, NASA is not the only space agency that has high hopes regarding the exploration of the Moon. The Indian Space Research Organization (ISRO) is another agency heavily involved in space activities.

 

Credits: ISRO

 

Interest in undertaking a lunar scientific mission was sparked at a meeting of the Indian Academy of Sciences in 1999. One year later, the Astronautical Society of India made a recommendation supporting the idea.

 

The ISRO formed a National Lunar Mission Task Force that involved leading Indian scientists. The Task Force provided an assessment on the feasibility of such a mission. The mission, called Chandrayaan-1, was approved in November 2003 for an estimated cost of $83 million USD.

 

The Chandrayaan-1 spacecraft is a 1.5 meter cube with a weight mass of approximately 523 kg. The spacecraft bus is based on an already developed meteorological satellite. Chandrayaan-1 will carry a 30 kg probe that will be released to penetrate the lunar surface. The power for the onboard systems is generated by a solar panel. The 750 watts generated by the solar panel will be stored by the rechargeable batteries onboard the spacecraft. Maneuvering in the lunar orbit is done using a bipropellant propulsion system.

 

Credits: ISRO

 

The scientific payload contains a diverse collection of instruments. The instruments were designed and developed by ISRO, ESA, NASA, and the Bulgarian Space Agency.

 

There are two instruments that will map the surface of the Moon: the Terrain Mapping Camera (TMC) will produce a 5 meter resolution map of the surface, and the Lunar Laser Ranging Instrument (LLRI) will scan the lunar surface and determine the surface topography.

 

The X-ray spectrometer onboard the spacecraft has three components: the Imaging X-ray Spectrometer (CIXS), the High Energy X-ray/gamma ray spectrometer (HEX), and the Solar X-ray Monitor (SXM). The X-ray spectrometer will measure the concentration of certain elements on the lunar surface as well as monitor the solar flux in order to normalize the results of the measurements taken.

 

The mineralogical configuration of the surface will be mapped by four instruments: the Hyper Spectral Imager (HySI), the Sub-keV Atom Reflecting Analyzer (SARA), the Moon Mineralogy Mapper (M3), and the Near-Infrared Spectrometer (SIR-2).

 

The Radiation Dose Monitor (RADOM-7) will record the radiation levels in the lunar orbit.

 

Credits: ISRO

 

ISRO has two operational launch vehicles: the Polar Satellite Launch Vehicle (PSLV) and the Geosynchronous Satellite Launch Vehicle (GSLV). For Chandrayaan-1, ISRO has chosen to use PSLV as a launch vehicle. The PSLV developmental flights were completed in 1996 and the rocket has had 12 successful missions since then. PSLV is 44.43 meters tall and has a weight of 294 tonnes at launch. It can inject a payload of 1,000 kg – 1,200 kg into a polar orbit.

 

The launch of the Chandrayaan-1 mission is scheduled for the end of October 2008. The PSLV rocket will take off from the Satish Dhawan Space Center in Sriharikota on the southeast coast of India. The transfer to the lunar orbit will take approximately five days and after additional maneuvers the spacecraft will reach its final polar orbit, 100 km above the surface. The spacecraft will be operational for two years.

 

The Chandrayaan-1 mission opens the door to future lunar missions. ISRO has already committed to a second Chandrayaan mission that will land a rover on the surface of the Moon. The rover will perform a number of experiments on the lunar surface and the results will be relayed to Earth by the Chandrayaan-2 orbiter.

 

We will come back with more details about the Chandrayaan-1 mission as the events unfold. Please stay tuned on the OrbitalHub frequency.

 

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10-3-08

Carnival of Space #73

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The Carnival of Space #73 is hosted this week by Alice Enevoldsen at Alice’s Astro Info. This week’s Carnival theme is the celebration of NASA’s 50th Anniversary.

 

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09-24-08

Scouting the Moon

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NASA’s return to the Moon requires careful preparation. Finding safe landing sites, locating potential resources, and taking measurements of the radiation environment are some of the tasks the Lunar Reconnaissance Orbiter (LRO) spacecraft will perform while in lunar orbit. LRO is an unmanned mission that will create a comprehensive atlas of the moon’s surface and resources.

 

The data gathered by LRO will be crucial in designing and building a permanent lunar outpost. The data will also be used to reduce the risk and increase the productivity of the future manned missions to the Moon.

 

The launch of LRO is scheduled for February 2009. An Atlas V rocket launched from the Kennedy Space Center will place the LRO on a transfer trajectory. After 4 days, the spacecraft will reach the Moon and after performing additional orbital maneuvers, it will move into its final orbit. The LRO’s final orbit will be a circular polar orbit 50 kilometers above the lunar surface.

 

Credits: NASA

 

The mission is designed to last for one year, with a possible extension. The total mass of the spacecraft is around 1,000 kilograms, of which 500 to 700 kilograms will be the fuel. The power is supplied by articulated solar arrays, and for the peak and eclipse periods a Li-Ion battery is used. The bandwidth of the communication link will be approximately 100-300 Mbps.

 

The LRO payload is comprised of six scientific instruments and one technology demonstration.

 

The Cosmic Ray Telescope for the Effects of Radiation (CRaTER) was built and developed by Boston University and the Massachusetts Institute of Technology in Boston. CRaTER will help explore the lunar radiation environment. The data gathered by measurements will help in the development of protective technologies that will keep future lunar crews safe.

 

The Diviner Lunar Radiometer Experiment (DLRE) was built and developed by the University of California, Los Angeles and the Jet Propulsion Laboratory in Pasadena, California. DLRE is capable of measuring surface and subsurface temperatures from orbit.

 

The Lyman-Alpha Mapping Project (LAMP) was built and developed at the Southwest Research Institute in San Antonio. LAMP will be used to map the entire lunar surface in the far ultraviolet spectrum.

 

Credits: NASA

 

The Lunar Exploration Neutron Detector (LEND) was developed at the Institute for Space Research in Moscow. This detector will create high-resolution maps of the hydrogen distribution and gather data about the neutron component of the lunar radiation.

 

The Lunar Orbiter Laser Altimeter (LOLA) was conceived and built at NASA’s Goddard Space Flight Center. LOLA will generate high-resolution three-dimensional maps of the moon’s surface.

 

The Lunar Reconnaissance Orbiter Camera (LROC), developed at Arizona State University at Tempe, will image the lunar surface in color and ultraviolet. LROC will be able to capture 1 m resolution images of the lunar poles.

 

The technology demonstration is called Mini-RF Technology Demonstration. The primary goal of this demonstration is to locate subsurface water ice deposits. The advanced single aperture radar (SAR) that will be used is capable of taking high-resolution imagery of the permanently shadowed regions on the lunar surface.

 

The data gathered by LRO will help us develop a better understanding of the lunar environment. This understanding is essential for a safe human return to the Moon and for the future exploration of our solar system.

 

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Yes, they do. They really do! One of NASA’s deep space mission probes, New Horizons, is undergoing a check. The mission operators wake the spacecraft out of hibernation once a year. A number of checks are performed: the antennas must be pointed toward Earth, the trajectory must be corrected if needed, and instruments must be calibrated. These checks last more than a usual visit to a doctor… about 50 days. The operators verify the health of the spacecraft, perform maintenance on subsystems and instruments, and gather navigation data.

 

Credits: NASA

 

The highlight of the current check was the upload of a new version of the software that runs the spacecraft’s Command and Data Handling system. The brain transplant, as it was called, was a success. The mission team at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland, sent the updates through NASA’s Deep Space Network (DSN) to the spacecraft. Two more updates are to be sent for both the Autonomy and Guidance and Control systems.

 

All commands that are sent to the spacecraft must pass a rigorous development and review process. After the command sequences are tested on the ground, the mission operations team will send them from the New Horizons Mission Operations Center at APL using the DSN, which is operated and managed by NASA’s Jet Propulsion Laboratory.

 

Credits: NASA

 

The New Horizons spacecraft was launched on January 19th, 2006 on top of an Atlas V rocket from Cape Canaveral Air Force Station, Florida.

 

The trajectory chosen for the probe is not complicated, as the probe is flying to Pluto using just one gravity boost from Jupiter. The journey consists of 5 segments: the early cruise, the Jupiter encounter, the interplanetary cruise, the Pluto-Charon encounter, and the Kuiper Belt.

 

During the early cruise segment of the voyage, spacecraft and instrument checkouts, instrument calibrations, and trajectory corrections were performed. Rehearsals for the Jupiter encounter were also conducted.

 

During the second segment of the voyage, the closest approach to Jupiter occurred on February 28th, 2007.

 

Credits: JHUAPL / SwRI

 

The third segment of the voyage consists mainly of spacecraft and instrument checkouts, trajectory corrections, instrument calibrations, and Pluto encounter rehearsals. This part of the voyage lasts for 8 years and is the current segment of the mission.

 

The Pluto-Charon encounter is planned for July 14th, 2015.

 

 

In the Kuiper Belt, plans are for one or two encounters with Kuiper Belt Objects (KBOs). These objects would be in the 40 to 90 kilometer size range and New Horizons would acquire the same data it collected during the Pluto-Charon encounter and send it back to Earth for analysis.

 

Credits: JHUAPL / SwRI

 

New Horizons is a small spacecraft. It weighs 478 kilograms in total, of which 77 kilograms is the hydrazine fuel, and 30 kilograms the scientific instruments. It measures 0.7×2.1×2.7 meters.

 

For communication with Earth, the spacecraft is using a 2.1 meter high-gain antenna. The data transfer rate is 38 kilobits per second at Jupiter, and 0.6 to 1.2 kilobits per second at Pluto. The data gathered during the encounter with Pluto will take 9 months to transmit back to Earth.

 

The scientific payload of the spacecraft draws less than 28 Watts of power. The mission uses a radioisotope thermoelectric generator (RTG) for power generation. The RTG contains 11 kilograms of plutonium dioxide. At the start of the mission, the RTG provided 240 Watts of energy at 30 Volts. Due to the decay of the plutonium, the power output decreases during the mission, and by the time of the Pluto encounter the RTG will only produce about 200 Watts.

 

The scientific instruments that were selected meet the mission’s goals. NASA set out a list of things it wanted to know about Pluto: the composition and behavior of the atmosphere, the appearance of the surface, the geological structures on the surface of Pluto, etc. The scientific payload contains seven instruments.

 

Credits: NASA

 

Ralph is a visible and infrared imager/spectrometer. It will obtain high-resolution color maps and surface composition maps of the surfaces of Pluto and Charon.

 

Alice is an ultraviolet imaging spectrometer. It will be used to analyze the composition and the structure of Pluto’s atmosphere and to look for atmospheres around Charon and Kuiper Belt Objects (KBOs).

 

REX is the Radio Science Experiment. It is a passive radiometer that measures atmospheric composition and temperature by using what is called an occultation technique: after passing Pluto, the spacecraft will point its antenna back to Earth and record the transmissions sent by the NASA’s DSN. The alterations of the transmissions caused by Pluto’s atmosphere will be recorded and sent back to Earth for analysis. REX will also be used to measure weak radio emissions from Pluto itself.

 

LORRI stands for Long Range Reconnaissance Imager. It is a telescopic camera and it will be used to obtain encounter data at long distances, to map Pluto’s far side and to provide high-resolution geologic data. LORRI will take images having 100-meter resolution.

 

SWAP, the solar wind and plasma spectrometer, stands for Solar Wind Around Pluto. It will measure the atmospheric escape rate and it will observe Pluto’s interaction with solar wind, determining whether Pluto has a magnetosphere or not.

 

Credits: NASA / JHUAPL

PEPSSI, Pluto Energetic Particle Spectrometer Science Investigation, is an energetic particle spectrometer used to measure the composition and density of plasma (ions) escaping from Pluto’s atmosphere.

 

SDC is the Student Dust Counter. It is the first scientific instrument built by students mounted on a space probe. It measures the space dust impacting the spacecraft during the voyage across the solar system, recording the count and the size of dust particles. It was built primarily by students from the University of Colorado in Boulder, with supervision from scientists.

 

If you want to know the present location of the spacecraft, there is a dedicated page on APL that you can visit.

 

For more information on the New Horizons Mission you can read the New Horizons Missions Guides document on the APL website.

 

The New Horizons Mission also has a page on Twitter.

 

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09-11-08

Carnival of Space #70

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Welcome to The OrbitalHub – the place where space exploration, science, and engineering meet. My name is DJ and I will be your host for this week’s Carnival. This is not only my first time participating in the Carnival, but also my first time hosting it. I hope you will enjoy reading this week’s entries.

 

Stuart Atkinson at the Cumbrian Sky points out that ESA marked a successful and historic day by beginning to involve the public more in their missions. He reminds us about some past missions that ESA was very reluctant to share with the general public.

 


Credits: NASA

 

On October 10, 2008, the Space Shuttle Atlantis will lift off on a fourth service mission to the Hubble Space Telescope. This sky veteran has served astronomers over the past (almost) two decades. On Astronomy at the CCSSC Rosa Williams explains why this mission is important and presents the upgrades that Hubble will undergo.

 

Space Shuttle flights may end in 2010. Alpha Magnetic Spectrometer, an ambitious cosmic ray experiment, is completed and sitting on the ground without a ride to the Space Station. The AMS mission may coincide with Shuttle retirement. Read The Last Flight at A Babe in the Universe to find out how scientists and the US Congress strongly support an extra mission for AMS. One controversial plan would deliver AMS and retire an Orbiter in space. The AMS mission would be a dramatic end to the Shuttle era.

 

On Kentucky Space, we can see how The Space Systems Design Studio at Cornell has been studying some superconducting technologies that might enable the building of modular spacecrafts.

 

 

Alexander DeClama, on Potentia Tenebras Repellendi, outlines more arguments on why space exploration is justified. Many byproducts of the space industry have migrated into healthcare and other industries over the years, bringing with them increased quality and reliability.

 

Centauri Dreams, in Cepheid Variables: A Galactic Internet?, looks at a recent paper that speculates on how a super-civilization might be able to modulate the extremely useful (and highly visible) Cepheid variable stars to encode a signal, for broadcast as one type of interstellar beacon. Intriguingly, if such a long-shot scenario turned out to be true, we might actually have data that could confirm it in existing records about Cepheid variables. The authors suggest how we might parse that data, and how future observations could help with such studies.

 

Ian Musgrave at Astroblog presents an animation of a cloud floating high above the Martian surface. He used Mars Express VMC camera images that ESA has released to the general public for analysis and processing.

 

Inspired by an article on Centauri Dreams, Music of the Spheres does some virtual space sailing with the help of the Orbiter space flight simulator and a solar sail add-on.

 

On The Planetary Society Weblog, Emily Lakdawalla covers a hot topic this week in the blogosphere: the encounter of ESA’s Rosetta with asteroid Steins.

 

David Portree of Altair VI describes the challenges that astronauts must face living and working in microgravity and an ambitious plan for the settlement of Mars in Delivering settlers to Mars (1995). The plan was initially published in the August 1995 issue of the Journal of the British Interplanetary Society by NASA Ames Research Center engineer Gary Allen.

 

Since the landing on Mars, the Phoenix lander has developed some odd little clumps on one of its legs, leading to speculations about their origin. Read about them on The Meridiani Journal in What is growing on Phoenix?

 

Even if space is a very harsh environment, it has been demonstrated that the water bears, a sea-monkey-like creature, can survive in the hard vacuum of space. Read all about it on Visual Astronomy in the article that Sean Welton has submitted for this week’s Carnival: Bears in Space?

 

Any old school astronomy geeks around here? Steinn Sigurdsson presents an illustration of Homeric Epicycles on Dynamics of Cats.

 


Credits: NASA/Pat Rawlings

 

Arthur C. Clarke’s vision of the future seems to be closer to reality as advances are made in separating carbon nanotubes. Read Brian Wang’s post Advance in separating carbon nanotubes brings space elevators a step closer at Next Big Future. This is a significant step towards building a space elevator and towards wider scale use of carbon nanotubes for other applications.

 

The future in space (and on Earth) of the next 20 years is so bright, you’ll probably need shades… Bruce Cordell of 21st Century Waves explains why in the post Why the World is Not Going to End.

 

It seems like the LHC (Large Hadron Collider) has an abort button! Thankfully, LHC physicists have a sense of humor about all of this doomsday mumbo-jumbo. Dave Mosher of Space Disco posted a picture of the ‘device’ in The LHC’s Abort Button.

 

At One Astronomer’s Noise, Nicole Gugliucci tells us about the successful attempt to resolve the super massive black hole at the center of our galaxy. Astronomers used what is called 1.3mm VLBI (Very Long Baseline Interferometry). VLBI is a technique that allows you to create a giant virtual telescope by linking multiple telescopes across long distances.

 

Measuring the positron emissions of the giant black hole at the center of the universe is quite a challenge. Ethan Siegel, at Starts With A Bang!, presents measurements taken by a detector in the gamma-ray domain and why these measurements are up for debate.

 

On Cosmic Ray, Ray Villard explores the possibility that the satellites of a Jovian-like planet orbiting around Epsilon Eridani, a star only 10 light-years away from our solar system, could harbor the seeds of life.

 


Credits: MOST Science Team

 

David Gamey, from Mang’s Bat Page, posted three articles about MOST (Microvariability and Oscillations of Stars), the suitcase sized microsatellite designed to probe stars and extra solar planets by measuring tiny light variations undetectable from Earth. By using a computer-controlled telescope, an astronomer from Toronto was able to catch MOST on camera. The MOST also started to offer its services to the public: Canadian amateur astronomers can win time on MOST. Even though it is a small telescope, MOST can be used to detect asteroids in an exo planetary system.

 

If you are an amateur astronomer, Alan Dyer at What’s Up Astronomy can show you how to catch on camera a cosmic flasher. Under the right conditions, the sunlight, reflected by the solar panels of communication satellites, can be observed from Earth.

 

The Earth is not left out this week. Phil Plait aka The Bad Astronomer, at Bad Astronomy, presents Ten things you don’t know about the Earth. I do not want to spoil the pleasure of reading the post, but I have to mention one of them: there is a measurable effect due to the centrifugal forces caused by the spinning motion of the Earth. The Earth’s diameter measured across the Equator is ~42km bigger than the diameter measured between the poles!

 

That’s it for this week’s Carnival! Thanks to everyone who submitted an entry. I enjoyed reading all of the posts and getting to know some members of the community. For more details on the Carnival of Space and past editions, you can check out the Carnival page at Universe Today. Many thanks to Fraser Cain at Universe Today for inviting me to host this Carnival.

 

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