News continues to be slow and my workload high, so I will post (with permission) another abstract from the recent Low Cost Planetary Mission conference. The entry of India and China into the group of planetary faring nations will expand the roster of missions we'll be seeing the next decades. Our moon is a complex world, and exploring a new region by this joint Indian-Russian mission of the surface along with orbital observations is likely to bring new discoveries.
CHANDRAYAAN-2 MISSION. J. N. Goswami1 and M. Annadurai2, 1Physical Research Laboratory, Ahmedabad-380009, India, 2ISRO Satellite Center, Bangalore-560017, India.
The first Indian planetary mission to moon, Chandrayaan-1 [1], with a suite of Indian and International payloads on board, collected very significant data over its mission duration of close to one year. The success of this mission provided the impetus to implement the second approved Indian mission to moon, Chandrayaan-2, with an Orbiter-Lander-Rover configuration [2]. This will be a collaborative mission between the Indian Space Research Organization (ISRO) and the Federal Space Agency of Russia. ISRO will be responsible for the Launch Vehicle, the Orbiter and the Rover while the Lander will be provided by Russia.
The orbiter for the Chandrayaan-2 mission is similar to that in Chandrayaan-1 from structural and propulsion aspects. The indigenously developed Geostationary Satellite Launch Vehicle, GSLV(Mk-II), will place the Orbiter-Lander-Rover in GTO (180km-36,000km), following which the Orbiter will boost the orbit to LTT. Separation of Orbiter and the Lander-Rover modules will take place in LTT and they will reach lunar polar orbit independently. The orbiter will be placed in an elliptical (5000km-200km) polar orbit prior to the descent of the Lander-Rover module to the lunar surface. Multiple communication links involving Rover-Lander-Orbiter-Earth, direct Lander-Earth and Rover-Orbiter will be implemented.
Althouh the exact landing location is yet to be finalized, a high latitude location is preferred from
scientific interest. The orbiter will be finally placed in a 200 km circular orbit and the instruments on board will have a close up view of the moon. The scientific payloads on the orbiter include a Terrain Mapping Camera (TMC-2), an Imaging Infra-red Spectrometer (IIRS), a Synthetic Aperture Radar (SAR), a Collimated Large Area Soft X-ray Spectrometer (CLASS), and a Neutral Mass Spectrometer (ChASE-2). TMC will provide 3D imaging and DEM, while the IIRS will cover the 0.8-5 micron region and collect information on mineralogy, detect OH and H2O on lunar surface and measure thermal emission from the moon. CLASS is an improved version of C1XS flown on Chandrayaan-1 for inferring chemical composition based on detection of X-rays emitted from lunar surface during solar flares. ChASE-2 is a modified version of ChASE on the Moon Impact Probe (MIP) on Chandrayaan-1 that provided hints for the presence of water molecule and CO2 in the lunar exosphere. The Synthetic Aperture Radar will include both L (1.25 GHz) and S (2-2.2 GHz) bands with selectable (few meter) resolution.
There will be two payloads on the Rover: an Alpha Particle induced X-ray Spectrometer (APXS) and Laser Induced Breakdown Spectroscopy (LIBS) for studies of chemical composition and volatiles present in lunar surface near the landing site. The Lander will have a suite of Russian instruments to study physical and chemical properties of the lunar surface and sub-surface material, lunar environment and siesmic activity [3]. The lander will have direct communication link to Earth Stations as well as via Orbiter and act as the hub for communication with the Rover. The design and development of the various mission elements as well as of the scientific payloads are currently in progress both in India and in Russia.
References: [1] Goswami J. N. & Annadurai M. (2009) Current Science 96, 486-491. [2] Goswami J. N. & Annadurai M. (2011) LPS 42 #2042,. [3] Mitrofanov I. G. et al. (2011) LPS 42, #1798.
Friday, August 26, 2011
Tuesday, August 23, 2011
TiME and Updates
It's summer time, which means that news is slow and I'm spending over half my time doing field work for my research. Anticipating both a slowing of news and limits on my time, I've lined up a series of abstracts and news releases that either update or expand on a future mission proposal. If you assiduously scan the Internet for this type of news, I apologize for the repetition. Otherwise, I hope you find these posts informative. When news does occur, I will report it.
Updates
NASA continues to study options for missions for Europa with an update promised for this Fall. The proposals under consideration would use the Stirling-based ASRGs rather than the MMTGs that had been planned for the flagship mission. This probably both reflects the lack of a start of new plutonium production (ASRGs use approximately a quarter the plutonium of the MMTGs for the same power output) and the lower cost of the expected missions (NASA has been reluctant to commit a multi billion dollar mission to the still unflown ASRG technology).
The latest cost projections for the James Webb Space Telescope that will be the successor to the Hubble Telescope are $8B for the hardware and $700M for the first five years of operations after launch. The journal Nature reports that NASA has proposed taking half the money still needed from the science program and half from the rest of NASA's programs. Editorial Thoughts: In the last decade, NASA reduced science spending to fund the manned spaceflight program; if approved this proposal would tax the manned spaceflight program to support science. It's possible that the planetary program would also be reduced to help fund the Webb Telescope. This telescope promises to be a cornerstone mission to understanding the early history of the universe, and while I would hate to see a planetary mission not flown, I'd hate to see this telescope cancelled even more. (For a less optimistic view of NASA's budget problems, check out NASA Watch.)
The White House has ordered all federal agencies, including NASA, to prepare their FY13 budget proposals, which will be submitted to Congress next winter, assuming a 5% cut from this year and identifying an additional 5% cut that could be taken. Editorial Thoughts: I don't know what NASA's planetary budget will be two years from now, except that no further decline than already planned may be good news.
Titan Mare Explorer (TiME): A Discovery Mission to Titan’s Hydrocarbon Lakes
This mission to place a scientific probe to float in a Titan lake has been a popular one with readers (and myself). At the Low Cost Planetary Mission conference a couple of months ago, the current plans were presented. The abstract from that talk is republished with permission.
Abstract. The Titan Mare Explorer (TiME) will land on Ligeia Mare, one of three large methane seas discovered by Cassini in the northern hemisphere of Titan. The seas of Titan provide an opportunity to explore a planetary surface whose chemical constituents are radically different from Earth, with liquid hydrocarbons making up the lakes, rivers, seas, rain and clouds seen by Cassini-Huygens. The seas of Titan are also repositories of organic molecules, chemically generated in the atmosphere above the sea, altered in ways we do not yet know on the surface, then deposited in the polar seas. The seas provide chemical and isotopic clues to: the processes of organic chemical evolution that have gone on for billions of years on Titan; perhaps the original materials from which Titan formed; and a medium within which networks of organic reactions, different from those in the aqueous medium of Earth, proceed toward a threshold that could be considered as life.
The self-contained, ASRG-powered TiME capsule will enter directly into Titan’s atmosphere, to float on the Ligeia sea. It is designed to operate in an almost completely autonomous manner, floating with the wind and waves. The payload consists of just three instruments, focusing on organic chemistry, meteorology, seafloor topography, and sea characteristics. This short, simple, passive mission architecture is key to enabling Titan science within the Discovery program.
The next major step in understanding Titan will be achieved through the two goals of TiME: 1) Understand Titan’s methane cycle through study of a Titan sea, and 2) Investigate the history of Titan and explore the limits of life. The science objectives to support these goals focus on determining the key unknowns for Titan’s seas: their chemistry, meteorology at the sea surface, depth, and sea properties. TiME has a small, high-heritage payload of three instruments: a neutral mass spectrometer, a meteorology and physical properties package, and an imaging system.
The science objectives of TiME are highly responsive to NASA and Discovery program goals and the key themes and science questions in the NRC Decadal Survey for Planetary Science. TiME will directly measure the composition of one of the major organic inventories on Titan, responsive to the ‘Volatiles and Organics: The Stuff of Life’ theme. The noble gas and isotopic inventories to be measured by TiME are highly relevant to the cross-cutting theme of ‘Origin and Evolution of Habitable Worlds’, under ‘What planetary processes are responsible for generating and sustaining habitable worlds?’. TiME will examine the extent to which organic chemistry on Titan has progressed toward or even beyond the threshold of biochemistry, also relevant to the Decadal theme of ‘Origin and Evolution of Habitable Worlds’. The study of the first active liquid cycle on a planet other than Earth, and of Titan’s marine processes are directly relevant to ‘Processes: How Planetary Systems Work’.
TiME will reduce the risk and enhance the science return from future Flagship-class missions by exploring in situ a key component of Titan’s methane cycle, and pathfinding operations in Titan’s extraterrestrial marine environment. Future missions that arrive after Earth has set from view of Titan’s high northern latitudes would need to include a costly relay spacecraft or target the much smaller southern lakes. An opportunity such as that embodied in TiME will not occur again for almost 30 years. In situ exploration of a major sea is the essential next step for advancing our understanding of Titan, provides an unprecedented opportunity to engage the public, and will be a reminder of the excitement inherent in visiting an unexplored and exotic environment for the first time.
Editorial Thoughts: All three Discovery mission finalists (which also include a comet multi-lander and a Mars geophysical station) are compelling, and I hope that each gets to fly. TiME is the only mission, so far as I know, that must be selected in this competition to fly so that it lands when Titan's northern lakes are in view of Earth. Assuming that this mission survives the engineering and programmatic reviews over the next year, my guess is it has a high chance of selection.
Updates
NASA continues to study options for missions for Europa with an update promised for this Fall. The proposals under consideration would use the Stirling-based ASRGs rather than the MMTGs that had been planned for the flagship mission. This probably both reflects the lack of a start of new plutonium production (ASRGs use approximately a quarter the plutonium of the MMTGs for the same power output) and the lower cost of the expected missions (NASA has been reluctant to commit a multi billion dollar mission to the still unflown ASRG technology).
The latest cost projections for the James Webb Space Telescope that will be the successor to the Hubble Telescope are $8B for the hardware and $700M for the first five years of operations after launch. The journal Nature reports that NASA has proposed taking half the money still needed from the science program and half from the rest of NASA's programs. Editorial Thoughts: In the last decade, NASA reduced science spending to fund the manned spaceflight program; if approved this proposal would tax the manned spaceflight program to support science. It's possible that the planetary program would also be reduced to help fund the Webb Telescope. This telescope promises to be a cornerstone mission to understanding the early history of the universe, and while I would hate to see a planetary mission not flown, I'd hate to see this telescope cancelled even more. (For a less optimistic view of NASA's budget problems, check out NASA Watch.)
The White House has ordered all federal agencies, including NASA, to prepare their FY13 budget proposals, which will be submitted to Congress next winter, assuming a 5% cut from this year and identifying an additional 5% cut that could be taken. Editorial Thoughts: I don't know what NASA's planetary budget will be two years from now, except that no further decline than already planned may be good news.
Titan Mare Explorer (TiME): A Discovery Mission to Titan’s Hydrocarbon Lakes
This mission to place a scientific probe to float in a Titan lake has been a popular one with readers (and myself). At the Low Cost Planetary Mission conference a couple of months ago, the current plans were presented. The abstract from that talk is republished with permission.
Abstract. The Titan Mare Explorer (TiME) will land on Ligeia Mare, one of three large methane seas discovered by Cassini in the northern hemisphere of Titan. The seas of Titan provide an opportunity to explore a planetary surface whose chemical constituents are radically different from Earth, with liquid hydrocarbons making up the lakes, rivers, seas, rain and clouds seen by Cassini-Huygens. The seas of Titan are also repositories of organic molecules, chemically generated in the atmosphere above the sea, altered in ways we do not yet know on the surface, then deposited in the polar seas. The seas provide chemical and isotopic clues to: the processes of organic chemical evolution that have gone on for billions of years on Titan; perhaps the original materials from which Titan formed; and a medium within which networks of organic reactions, different from those in the aqueous medium of Earth, proceed toward a threshold that could be considered as life.
The self-contained, ASRG-powered TiME capsule will enter directly into Titan’s atmosphere, to float on the Ligeia sea. It is designed to operate in an almost completely autonomous manner, floating with the wind and waves. The payload consists of just three instruments, focusing on organic chemistry, meteorology, seafloor topography, and sea characteristics. This short, simple, passive mission architecture is key to enabling Titan science within the Discovery program.
The next major step in understanding Titan will be achieved through the two goals of TiME: 1) Understand Titan’s methane cycle through study of a Titan sea, and 2) Investigate the history of Titan and explore the limits of life. The science objectives to support these goals focus on determining the key unknowns for Titan’s seas: their chemistry, meteorology at the sea surface, depth, and sea properties. TiME has a small, high-heritage payload of three instruments: a neutral mass spectrometer, a meteorology and physical properties package, and an imaging system.
The science objectives of TiME are highly responsive to NASA and Discovery program goals and the key themes and science questions in the NRC Decadal Survey for Planetary Science. TiME will directly measure the composition of one of the major organic inventories on Titan, responsive to the ‘Volatiles and Organics: The Stuff of Life’ theme. The noble gas and isotopic inventories to be measured by TiME are highly relevant to the cross-cutting theme of ‘Origin and Evolution of Habitable Worlds’, under ‘What planetary processes are responsible for generating and sustaining habitable worlds?’. TiME will examine the extent to which organic chemistry on Titan has progressed toward or even beyond the threshold of biochemistry, also relevant to the Decadal theme of ‘Origin and Evolution of Habitable Worlds’. The study of the first active liquid cycle on a planet other than Earth, and of Titan’s marine processes are directly relevant to ‘Processes: How Planetary Systems Work’.
TiME will reduce the risk and enhance the science return from future Flagship-class missions by exploring in situ a key component of Titan’s methane cycle, and pathfinding operations in Titan’s extraterrestrial marine environment. Future missions that arrive after Earth has set from view of Titan’s high northern latitudes would need to include a costly relay spacecraft or target the much smaller southern lakes. An opportunity such as that embodied in TiME will not occur again for almost 30 years. In situ exploration of a major sea is the essential next step for advancing our understanding of Titan, provides an unprecedented opportunity to engage the public, and will be a reminder of the excitement inherent in visiting an unexplored and exotic environment for the first time.
Editorial Thoughts: All three Discovery mission finalists (which also include a comet multi-lander and a Mars geophysical station) are compelling, and I hope that each gets to fly. TiME is the only mission, so far as I know, that must be selected in this competition to fly so that it lands when Titan's northern lakes are in view of Earth. Assuming that this mission survives the engineering and programmatic reviews over the next year, my guess is it has a high chance of selection.
Sunday, August 14, 2011
Red Dragon to Mars?
Click on the screen shot to read Space.com's article on Red Dragon
There's an interesting Discovery mission proposal in the works. It would use a commercial spacecraft in development to land what could be a very large payload on Mars within a price cap of $425M.
The spacecraft would be a derivative of the Dragon manned capsule under development by the Space Explorations Technologies (SpaceX) corporation. The capsule currently being developed would ferry crews and cargo to and from the International Space Station. While the current capsule is designed to splash down in the ocean, a future version is planned that would land using rockets.
The founder of SpaceX thinks big, and wants to develop technology that eventually will enable manned landings on Mars. As a result, the capsule is being developed with eventual use on Mars in mind.
Chris McKay at NASA's Ames research center is working with SpaceX to define a Discovery proposal that would use a version of the Dragon capsule -- nicknamed 'Red Dragon' -- to put a payload on Mars with a launch in 2018. The goals of the mission would be to drill down a meter or more below the surface in an area known to have ice just below the surface. (Two possible landing sites: Near the Phoenix lander or near the Viking 2 lander.) Samples would be brought into the capsule to be analyzed for molecules that would indicate life.
While the proposal in development is modest in its scope, the capsule would be capable of landing several tons of payload, more than all the payloads delivered to Mars to data.
Editorial Thoughts: What to make of this proposal? SpaceX is a credible company that has successfully developed the Falcon 9 booster and has orbited and returned a prototype Dragon capsule. It's recently won some big launch contracts, showing that the satellite industry is comfortable with its capabilities.
If the Red Dragon lander were to be developed, it might significantly drive down the cost of landing payloads on Mars since the technology would be based on a production line spacecraft instead of being a unique design. There's been a lively discussion at the Unmannedspaceflight forum discussing what might or might not be possible.
My take on this is that it's a clever idea, but many things have to happen before it could fly. SpaceX would have to complete development of its Falcon Heavy booster that would launch the mission. NASA requires several successful launches before it will commit a science mission to a new booster. The Dragon capsule would have to be enhanced to land on rockets. The entire entry, landing, and descent at Mars would have to be thoroughly tested. SpaceX might treat much of this development as internal R&D and not charge it to an individual Discovery mission. Even so, I wonder if the first flight can be kept within the Discovery mission cost cap. NASA would also have to pay for the Falcon Heavy launch in addition to the $425M for the lander and payload; I don't know how this launcher's costs would compare to launch costs for other Discovery proposals. A launch in 2018 given everything that must happen seems ambitious.
While the potential to land large payloads is enticing, larger payloads cost more to develop and test than smaller payloads, and fully utilizing a Red Dragon's capacity could exceed a Discovery mission budget. And the capsule itself might make it hard to deliver some types of payloads. For example, could a reasonably large rover be packaged inside and then safely exit the capsule?
There are also questions of whether this is the best choice of landers for the type of mission McKay envisions. Could the drill and instruments be flown on the proven Phoenix lander instead? (Note: McKay is a seasoned researcher, so he's undoubtedly already asked himself that question. Red Dragon may enable a key capability for this mission that the Phoenix lander doesn't within a $425 mission cap.)
Many questions, and for the moment few answers, which would be expected for a new idea and a spacecraft that is still under development. If these questions can be answered with clever engineering and within tight budget caps, then this would be an exciting development. I hope we hear more about Red Dragon in the future.
Resources:
Space.com article on Red Dragon
MSNBC interview with SpaceX CEO on his plans for Mars
Wikipedia background on SpaceX and the Dragon capsule
Saturday, August 6, 2011
PriME/MASPEX and Updates
I'll cover the updates first. Aviation Week and Space Technology (AWST) has had a series of good articles on planetary exploration and space science in the last two issues. (Unfortunately, most require a subscription.) Amy Svitak, formerly with Space News, now writes for AWST, and continues her excellent coverage of policy issues there.
In an article discussing issues with NASA and ESA joint missions across a breadth of disciplines, Svitak reports that, "ESA is considering modifying the proposed Ganymede orbiter to to incorporate some Europa science." Presumably, this would be science gathered in a series of Europa flybys. (Source: NASA's money woes thwart joint science missions with ESA)
In another article, Svitak reports that ESA is considering downsizing or eliminating its technology demonstration lander from the joint ESA-NASA 2016 mission so that more funding can be applied to the 2018 joint rover mission. (Source: Europe could downsize Mars 2016 mission)
In yet another article, (this time not by Svitak), AWST reports that the Russian Phobos-Grunt sample return mission that will be launched this year is on track.
PriME/MASPEX
Sometimes a good mission concept can enabled by a single instrument. When NASA announced it's list of candidate missions for its next Discovery mission (http://futureplanets.blogspot.com/2011/05/discovery-mission-candidates-announced.html), it also listed three missions that would be funded for technological development to enhance their ability to compete in future selections. One of these was the PriME mission, "Primitive Material Explorer (PriME), which would use an advanced mass spectrometer to provide high precision measurements of the the composition of a comet using a new, advanced mass spectrometer.
First some background on mass spectrometers, which are workhorse instruments in many laboratories and on many spacecraft. To over simplify what they do, mass spectrometers 'weigh' the chemical compounds found in a plasma or gas. (The composition of solids and liquids can be measured by heating them until they vaporize.) The weights of the different molecules form a mass spectra that can be interpreted to determine the compositon of the orginal material.
Two figures of merit are frequently quoted when comparing mass spectrometers. One is the range of masses they can measure, which are frequently expressed in atomic mass units (amu), which are approximately the mass of a single proton or neutron. The Cassini spacecraft's Ion and Neutral Mass Spectrometer (INMS) has a range of 1-99 amu, the Rosetta spacecraft has two mass spectrometers with ranges of 1-150 and 1-300 amu, and the Mars Science Laboratory's mass spectrometer has a range of 2-535 amu. The second figure of merit is the resolution of the measurements in terms of how finely different masses can be distinguished. (The websites for the different instruments either do not give the second figure or report it in different units.)
The PriME mission would fly a next generation space-borne mass spectrometer, MASPEX, with a range of 1-1000 amu. MSPEX's resolution and sensitivity would allow far more precise measurements of the composition of the gases released by a comet that has been possible with previous and current missions. MASPEX could help us work around a key limitation of any comet sample return launched this decade. We currently lack the technology to keep many of the cometary ices frozen throughout the long delivery back to Earth. As a result, we'd lose the ability to measure pristine samples. An instrument like MASPEX could enable more precise measurements at the comet of unaltered materials. It's not clear, however, that MASPEX would be flown on a sample return mission itself. A sample return mission is likely to sample the comet as far from the sun as possible to avoid its volatile outgassing and then head back as early as orbital mechanics allow. A spacecraft carrying MASPEX, however, would want to linger at the comet through out the periods of maximum outgassing closest to the sun. As a result, separate missions might be likely.
An enhanced mass spectrometer would be useful in missions to many types of destinations including Mars, Titan, and Enceladus.
We have no details on MASPEX's cost, mass, size, or power requirements compared to current generation mass spectrometers (which apparently can be among the heavier and more costly instruments for many missions). Hopefully, MASPEX will be competitive, and will provide a new level of capability for a wide range of missions. For some destinations, its improved capabilities would be enabling by itself, as with the PriME mission.
With the permission of the PriME mission's Principal Investigator, Dr. Anita Cochran, I'm reprinting an abstract on the PriME mission. I'm also reprinting a press release on the MASPEX mass spectrometer. I've read elsewhere that while this mission wasn't selected as a finalist for the current Discovery mission selection, the team plans to propose it again for the next selection.
The Primitive Material Explorer (PriME) Mission
Cochran, Anita L.; Weaver, H. A.; Science, PriME; Engineering Teams
American Astronomical Society, DPS meeting #42, #49.17; Bulletin of the American Astronomical Society, Vol. 42, p.1006
The Primitive Material Explorer (PriME) Mission is a proposed Discovery mission that will rendezvous with comet 46P/Wirtanen in 2021 in order to 1) clarify the roles played by comets in the formation and evolution of the Solar System and the origin of life; 2) ascertain the bulk physical properties, the surface geology, and the sources of activity in a fresh comet nucleus; and 3) investigate the compositional diversity of primitive material in the Solar System. PriME teams an experienced group of comet scientists (led by PI Anita Cochran and by DPI Harold Weaver) with university and industrial partners.
The PriME payload accomplishes the mission objectives with only three instruments. MASPEX (MAss Spectrometer for Planetary EXploration) has higher mass resolution and is more sensitive than any mass spectrometer ever flown. MASPEX will measure D/H in H2O, noble gases, isotopes of many species, and complex molecular compounds to test solar nebula models and the role comets played in delivering water and other biologically important materials throughout the Solar System. The VIS (Visible Imaging System), consisting of a Narrow Angle Camera (NAC) and Wide-Angle Camera (WAC), will constrain the conditions under which the building blocks of the outer Solar System were assembled by measuring key physical properties of the nucleus of 46P/Wirtanen. Using the radio antenna and close flybys of the nucleus, PriME will determine the mass of the nucleus to an accuracy of 1% and the bulk density and average porosity of the nucleus to better than 5%. All spacecraft subsystems have significant planetary flight heritage. The spacecraft is a high-heritage derivative of the Kepler and Deep Impact spacecrafts, compatible with the three launch vehicle families specified in the Discovery Announcement of Opportunity.
NASA selects SwRI mass spectrometer for technology development funding, possible future planetary mission
For immediate release
San Antonio — May 17, 2011 — NASA has selected Southwest Research Institute's MAss Spectrometer for Planetary EXploration (MASPEX) for technology development funding. Originally offered as part of the Primitive Material Explorer (PriME) mission proposal, the mass spectrometer was selected to further advance NASA's capability for evaluating the chemical composition of comets.
MASPEX is a highly sensitive ion and neutral mass spectrometer based on novel detection technologies under development by SwRI. Although similar to a spectrometer on the ESA Rosetta mission currently on course to reach comet 67P/Churyumov-Gerasimenko in 2014, MASPEX extends its resolution and sensitivity by one to two orders of magnitude. The spectrometer is designed to measure precisely the composition of volatile gases and plasmas found in planetary atmospheres as well as comets. Identification of isotopes in these extremely low-density populations is a particularly challenging target and an area where MASPEX is expected to excel. In addition to comets, the SwRI team is exploring a number of Earth-based spin-off applications of this novel technology.
Institute Scientist Dr. Hunter Waite and Program Director Dr. David Young, both of the SwRI Space Science and Engineering Division, serve as MASPEX co-principal investigators.
"With further development, MASPEX will have by far the highest sensitivity for identifying, measuring and sampling gases and plasmas of any mass spectrometer ever flown in space," says Waite.
"Measuring isotopic composition will yield for the first time quantitative clues to the origin of comets and other bodies in the solar system, and could provide valuable insights into the origin of life," Young adds.
To be considered for space flight, the SwRI team must demonstrate continued advancement of the technology in preparation for a future mission proposal. The spectrometer is one of three technology developments selected by NASA for further development.
In an article discussing issues with NASA and ESA joint missions across a breadth of disciplines, Svitak reports that, "ESA is considering modifying the proposed Ganymede orbiter to to incorporate some Europa science." Presumably, this would be science gathered in a series of Europa flybys. (Source: NASA's money woes thwart joint science missions with ESA)
In another article, Svitak reports that ESA is considering downsizing or eliminating its technology demonstration lander from the joint ESA-NASA 2016 mission so that more funding can be applied to the 2018 joint rover mission. (Source: Europe could downsize Mars 2016 mission)
In yet another article, (this time not by Svitak), AWST reports that the Russian Phobos-Grunt sample return mission that will be launched this year is on track.
PriME/MASPEX
Sometimes a good mission concept can enabled by a single instrument. When NASA announced it's list of candidate missions for its next Discovery mission (http://futureplanets.blogspot.com/2011/05/discovery-mission-candidates-announced.html), it also listed three missions that would be funded for technological development to enhance their ability to compete in future selections. One of these was the PriME mission, "Primitive Material Explorer (PriME), which would use an advanced mass spectrometer to provide high precision measurements of the the composition of a comet using a new, advanced mass spectrometer.
First some background on mass spectrometers, which are workhorse instruments in many laboratories and on many spacecraft. To over simplify what they do, mass spectrometers 'weigh' the chemical compounds found in a plasma or gas. (The composition of solids and liquids can be measured by heating them until they vaporize.) The weights of the different molecules form a mass spectra that can be interpreted to determine the compositon of the orginal material.
Two figures of merit are frequently quoted when comparing mass spectrometers. One is the range of masses they can measure, which are frequently expressed in atomic mass units (amu), which are approximately the mass of a single proton or neutron. The Cassini spacecraft's Ion and Neutral Mass Spectrometer (INMS) has a range of 1-99 amu, the Rosetta spacecraft has two mass spectrometers with ranges of 1-150 and 1-300 amu, and the Mars Science Laboratory's mass spectrometer has a range of 2-535 amu. The second figure of merit is the resolution of the measurements in terms of how finely different masses can be distinguished. (The websites for the different instruments either do not give the second figure or report it in different units.)
The PriME mission would fly a next generation space-borne mass spectrometer, MASPEX, with a range of 1-1000 amu. MSPEX's resolution and sensitivity would allow far more precise measurements of the composition of the gases released by a comet that has been possible with previous and current missions. MASPEX could help us work around a key limitation of any comet sample return launched this decade. We currently lack the technology to keep many of the cometary ices frozen throughout the long delivery back to Earth. As a result, we'd lose the ability to measure pristine samples. An instrument like MASPEX could enable more precise measurements at the comet of unaltered materials. It's not clear, however, that MASPEX would be flown on a sample return mission itself. A sample return mission is likely to sample the comet as far from the sun as possible to avoid its volatile outgassing and then head back as early as orbital mechanics allow. A spacecraft carrying MASPEX, however, would want to linger at the comet through out the periods of maximum outgassing closest to the sun. As a result, separate missions might be likely.
An enhanced mass spectrometer would be useful in missions to many types of destinations including Mars, Titan, and Enceladus.
We have no details on MASPEX's cost, mass, size, or power requirements compared to current generation mass spectrometers (which apparently can be among the heavier and more costly instruments for many missions). Hopefully, MASPEX will be competitive, and will provide a new level of capability for a wide range of missions. For some destinations, its improved capabilities would be enabling by itself, as with the PriME mission.
With the permission of the PriME mission's Principal Investigator, Dr. Anita Cochran, I'm reprinting an abstract on the PriME mission. I'm also reprinting a press release on the MASPEX mass spectrometer. I've read elsewhere that while this mission wasn't selected as a finalist for the current Discovery mission selection, the team plans to propose it again for the next selection.
The Primitive Material Explorer (PriME) Mission
Cochran, Anita L.; Weaver, H. A.; Science, PriME; Engineering Teams
American Astronomical Society, DPS meeting #42, #49.17; Bulletin of the American Astronomical Society, Vol. 42, p.1006
The Primitive Material Explorer (PriME) Mission is a proposed Discovery mission that will rendezvous with comet 46P/Wirtanen in 2021 in order to 1) clarify the roles played by comets in the formation and evolution of the Solar System and the origin of life; 2) ascertain the bulk physical properties, the surface geology, and the sources of activity in a fresh comet nucleus; and 3) investigate the compositional diversity of primitive material in the Solar System. PriME teams an experienced group of comet scientists (led by PI Anita Cochran and by DPI Harold Weaver) with university and industrial partners.
The PriME payload accomplishes the mission objectives with only three instruments. MASPEX (MAss Spectrometer for Planetary EXploration) has higher mass resolution and is more sensitive than any mass spectrometer ever flown. MASPEX will measure D/H in H2O, noble gases, isotopes of many species, and complex molecular compounds to test solar nebula models and the role comets played in delivering water and other biologically important materials throughout the Solar System. The VIS (Visible Imaging System), consisting of a Narrow Angle Camera (NAC) and Wide-Angle Camera (WAC), will constrain the conditions under which the building blocks of the outer Solar System were assembled by measuring key physical properties of the nucleus of 46P/Wirtanen. Using the radio antenna and close flybys of the nucleus, PriME will determine the mass of the nucleus to an accuracy of 1% and the bulk density and average porosity of the nucleus to better than 5%. All spacecraft subsystems have significant planetary flight heritage. The spacecraft is a high-heritage derivative of the Kepler and Deep Impact spacecrafts, compatible with the three launch vehicle families specified in the Discovery Announcement of Opportunity.
NASA selects SwRI mass spectrometer for technology development funding, possible future planetary mission
For immediate release
San Antonio — May 17, 2011 — NASA has selected Southwest Research Institute's MAss Spectrometer for Planetary EXploration (MASPEX) for technology development funding. Originally offered as part of the Primitive Material Explorer (PriME) mission proposal, the mass spectrometer was selected to further advance NASA's capability for evaluating the chemical composition of comets.
MASPEX is a highly sensitive ion and neutral mass spectrometer based on novel detection technologies under development by SwRI. Although similar to a spectrometer on the ESA Rosetta mission currently on course to reach comet 67P/Churyumov-Gerasimenko in 2014, MASPEX extends its resolution and sensitivity by one to two orders of magnitude. The spectrometer is designed to measure precisely the composition of volatile gases and plasmas found in planetary atmospheres as well as comets. Identification of isotopes in these extremely low-density populations is a particularly challenging target and an area where MASPEX is expected to excel. In addition to comets, the SwRI team is exploring a number of Earth-based spin-off applications of this novel technology.
Institute Scientist Dr. Hunter Waite and Program Director Dr. David Young, both of the SwRI Space Science and Engineering Division, serve as MASPEX co-principal investigators.
"With further development, MASPEX will have by far the highest sensitivity for identifying, measuring and sampling gases and plasmas of any mass spectrometer ever flown in space," says Waite.
"Measuring isotopic composition will yield for the first time quantitative clues to the origin of comets and other bodies in the solar system, and could provide valuable insights into the origin of life," Young adds.
To be considered for space flight, the SwRI team must demonstrate continued advancement of the technology in preparation for a future mission proposal. The spectrometer is one of three technology developments selected by NASA for further development.
Monday, August 1, 2011
Articles and a Blog
A couple of good articles were published today on the Juno and Mars Science Laboratory missions.
Nature: Closing in on Jupiter's Past
Aviation Week and Space Technology: NASA bets big rover on novel landing scheme
I also discovered a new blog that covers space exploration, including in-depth posts on planetary exploration. I'm not sure how I missed this blog for so long; perhaps because it's in Spanish and my search terms didn't translate well. (Google translate seems to do a pretty good job at providing readable English text.) I've added this blog to my blog list, and you can visit it at http://danielmarin.blogspot.com/.
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