Lunette: Reducing Network Mission Costs

Note: While I'm traveling this month with only occasional short access to the Internet, I'm reading through some of the back log of proposed mission concepts.  I'll post short summaries of the more interesting ideas.  Unfortunately, I'm unlikely to have time to search down Internet sites to provide hot links to the abstracts and presentations I'm reading.  I'll try to provide sufficient information on each that you can easily do a search to find the original documents.

In this post, I'll a mission concept for the Discovery program (~$425M PI cost, ~$800M fully burdened cost) that would explore the moon's interior.

The proposal was described in an extended abstract (2 pages) for this year's 41st Lunar and Planetary Science Conference.

Lunnette: Establishing a lunar geophysical network without nuclear power through a Discovery-class mission
LPSC abstract 2710.pdf

Studies of the interiors of the moon and planets has been repeatedly prioritized by review panels prioritizing future planetary exploration.  Planets and large moons have had complex interactions between the formation, evolution, and current state of their interiors and surfaces and, where they exist, their atmospheres.  While surfaces and interiors have received considerable attention, interiors have received much less investigation.  Gravity measurements from orbiters and flybys provide some information on interiors, but seismic and heatflow measurements are considered essential to extend our knowledge.  To date, only the moon has been investigated by a network of surface stations left by the Apollo astronauts.  Those instruments represent decade old technologies and were placed at sites chosen for surface geology rather than optimizing the design of the network.

The Lunette proposal attempts to address one of the major roadblocks to establishing surface networks, cost.  The current leading proposal for an initial four node lunar network, the International Lunar Network (ILN), reportedly would cost more than a New Frontiers mission (~$650M PI cost, ~$1.2B fully burdened cost).  I've seen estimates for a four node Mars network in the range of $1.5B.

The Lunette proposal would minimize costs through three strategies.  First it would use solar power in place of nuclear power and would "use new power management technology" to survive and operate through the long lunar night for at least two years of operation.  Second, it would place just three nodes on the surface instead of ILN's four.  And third, it would depend on international partners to supply and pay for a very broad band seismometer that would be an order of magnitude more sensitive than the Apollo seismometers, a short period seismometer, and a heat flow probe.  U.S. scientists would supply a low-frequency electromagenetic sounding instrument and a laser retroreflector.

Editorial thoughts:  Studying planetary interiors is important.  Two NASA missions in development, the JUNO Jupiter orbiter and the GRAIL lunar orbiters would study the interiors of their bodies using gravity and magnetometer measurements.  Studying the interiors of the moon and Mars from the surface is the next logical step.  If the Lunette team has found ways to dramatically reduce costs for surface networks, that would be welcome news.  The list of authors includes two authors from JPL, suggesting that the engineering analysis may be reasonably advanced.  (I don't recognize these author's names and so don't know if they are on the science or engineering side of JPL, and I can't do a web search from the tent I'm writing this in.)  On the other hand, the costs of many Discovery proposals reportedly have proven to have under estimated costs in the eyes of the panels that review the proposals.  Getting a network mission into even the cost cap of a New Frontiers mission would still be a significant achievement, though.  The Lunette proposal sounds like solid progress in that direction.

MoonRise Proposed New Frontiers Mission

The SPA basin lies almost entirely on the far side of the moon.  MoonRise would be the first mission to collect samples from that hemisphere.   In this topographic map, red indicates high elevations while purple indicates low elevations.  From Wikipedia based on Kaguya data.

Late last year, NASA announced three finalists in the selection for the next New Frontiers mission.  Two of the three missions, the SAGE Venus Lander and the OSIRIS-REx asteroid sample return mission have previously been discussed in this blog.  This time, I'll describe the goals for the third finalist, the lunar MoonRise South Pole-Aitken (SPA) basin sample return.  

Unfortunately, I largely will only be able to describe goals.  As with most mission proposals for the New Frontiers and Discovery programs, the proposing teams are keeping the implementation details to themselves.  It's common for these missions to be proposed several times, and there's no point to giving potential competitors ideas.  We do know that a single lander is being proposed (unlike a previous New Frontiers proposal to sample the SPA basin) and that there will be a communications satellite.  The goal is to gather 1 kg of lunar soil, which is expected to contain 10,000 2-4 mm particles, >3,000 4-10 mm framents, and "a significant number" of small rocks >1 cm.  Because large impacts spread material across the lunar surface and small impacts churn the local soils, it's believed that a single soil sample will sample a diversity of sites from within the basin.  Thanks to the plethora of satellites that have and are studying the moon, the proposers think that they can pick a site to optimize the value of that heterogeneous soil sample.  No rover would be needed to collect samples.

That's the what of the mission, but what about the why of the mission?  The SPA basin is the largest of the impact craters on the moon (and possibly the solar system) and was one of the earliest of the large lunar impacts (see Wikipedia article).  It is so large, that several later good sized impacts lie within it.  One of the key questions for the early history of the terrestrial planets has been the nature of the large bombardments of the planets near the end of their formation.  There's a debate about whether there was a single dramatic pulse of impacts or whether they were more spread out over time.  Samples from the SPA basin can date the impacts within the basin. Coupled with information on the dates of impacts elsewhere on the moon from samples collected in the 1970s, this mission could help to resolve this debate or take it in new directions.

A second goal for this mission is to use the samples to better understand the effect the initial and subsequent impacts had on the development of early planetary crusts.  Samples will allow us to determine how deeply the impacts penetrated the crust, the thermal state of the moon at the time of impact, and provide ground truth for the remote sensing data on the current surface of the basin.  

The third goal is to use the basin to collect samples from various depths of the lunar crust and possibly mantel.  The cumulation of large impacts within the basin means that samples are likely to have been thrown up from various depths beneath the surface.  Understanding how terrestrial planets differ with depth and across their surface has long been a goal of terrestrial and planetary science.

You can read about the goals of this mission in much more depth in the two following two-page abstracts from the last Lunar and Planetary Science Conference:

• SAMPLING THE SOUTH POLE-AITKEN BASIN: OBJECTIVES AND SITE SELECTION CRITERIA  
• PULLING MARBLES FROM A BAG: DEDUCING THE REGIONAL IMPACT HISTORY OF THE SPA BASIN FROM IMPACT-MELT ROCKS  

Editorial Thoughts:  The New Frontiers selections are highly competitive and it's not surprising that three finalists are all scientifically strong.  Any one of them will make a significant contribution to planetary science.  OSIRIS-REx would provide a major boost to the study of primitive bodies in the solar system and would build upon a number of previous missions and compliment the Rossetta comet mission.  SAGE would re-invigorate the study of the Venus surface and could be an American contribution to a series of missions to study Venus from several space agencies.  MoonRise would provide ground truth for the number of missions that have recently flown to the moon and the several that are planned in the coming decade.

Given that the science potential of all these missions would be high, the final selection is likely to be made on the basis of technical maturity, costs, and programmatic risks.  Unfortunately, the public has no insight into these issues and therefore has no way to handicap the selection.  The current date for the selection is April or May of 2011.

Europe Plans a Moon Lander

ESA is planning to land a probe in a lunar south polar crater by the end of this decade.  The landing site would be in an area of possible water ice.   ESA’s article on the mission lists the goals as “that it uses the latest navigation technology to fly a precise course from lunar orbit to the surface and touch down safely and accurately. On the way down, it must image the surface and recognize dangerous features by itself, using its own ‘intelligence’.  Then the Lander shall investigate this unique region with a suite of instruments. It will investigate the properties and possible health effects of radiation and lunar dust on future astronauts, and it will examine the soil for signs of resources that could be used by human explorers.”  The next step will be to further develop possible designs over the next 18 months.

Editorial Thoughts: I was unable to find much information on this lander and its goals.  This appears to be a technology development program run by ESA's Directorate of Human Spaceflight.  In its scope and goals, it appears to be similar to the proposed series of NASA Precursor missions that will prove new technologies and investigate possible locations for future manned flights.  Because the mission apparently will investigate sites with lunar ice, it has the potential of producing some good, original science.

Resources:

ESA article on the moon lander http://www.esa.int/esaCP/SEM83CIK97G_index_0.html

Information on the overall program http://www.esa.int/esaCP/SEMBM4CDNRF_Life_0.html  

Lander design concepts from http://www.esa.int/esaCP/SEM83CIK97G_index_1.html#subhead3

Upcoming Lunar Exploration Plans

Just a quick link to a short article at Space Daily about upcoming plans to explore the moon with unmanned missions.  http://www.moondaily.com/reports/Moon_Exploration_is_Not_Dead_999.html