Clementine 1
The Clementine 1 probe is best known for being the probe which first discovered water at the Moon's poles.
Clementine 1 was a very low budget probe paid for by the Department of Defense's Strategic Defense Initiative (SDI, aka "Star Wars") program.
What is less known is that Clementine headed off for a rendezvous with near-Earth asteroid Geographos, which makes a very close approach to Earth periodically.
Unfortunately, Clementine 1 failed en-route to Geographos. A software bug in its star tracking navigation system misled the probe to think it was improperly oriented. The software had insufficient fault tolerance in that the probe suddenly started spending a lot of fuel in endless reorientation attempts. The software should have put limits on how much fuel it could expend, at the very least. There are several mission critical "system fault tolerance" algorithms that should have been built in to prevent what happened. Instead, it just went on spending all its fuel, and by the time mission controllers on the ground were notified, it was out of fuel and could no longer rendezvous with Geographos.
NEAR probe and asteroids -- Mathilde and Eros
The NEAR (Near Earth Asteroid Rendezvous) mission was the first in NASA's Discovery program of "smaller, faster, cheaper" missions, formally started in 1994 under new NASA Administrator Dan Golden, though it reflected a fundamental change in NASA budgetary and programmatic philosophy under the George Bush Sr. and Bill Clinton administrations, and which continues to this day under George Bush Jr. The purpose of the Discovery program is to design a series of low cost spacecraft, each at a cost within $190 million of development costs and another $100 million of mission costs, and a time frame of 3 years from design to launch. It meant major cuts in porkbarrel NASA spending, though private operations such as SpaceDev can still cut costs a lot more.
NEAR was launched successfully on February 17, 1996.
The main goal of NEAR was to be the first probe to orbit an asteroid. The near-Earth asteroid Eros was chosen, as it's a large asteroid and is more economically accessible than other large asteroids (though there are more accessible small asteroids).
Eros is an elongated asteroid about 40 km x 14 km x 14 km in size. The orbit around the asteroid was complex, and this was our first experience in orbiting an asteroid.
Eros arrived at the asteroid on Valentine's Day in the year 2000, and continued studying the asteroid for approximately a year. In the end, Eros landed on the asteroid, even though it was not designed to land. The mission was a resounding success.
Eros, two views, both sides. Photo by NASA and JHUAPL.
However, the mission was not without its problems. It was initially planned to rendezvous in January of 1999. However, a scheduled burst of rocket thrust on the main engine during an orbital refinement maneuver caused a vibration which exceeded the safety threshold setting in the computer, and the probe automatically shut down the engine immediately, missing a timely burn required for rendezvous. By the time everything was sorted out, it was far too late for another orbital correction for rendezvous and so the probe couldn't rendezvous for another year. However, the fast flyby of Eros gave valuable information for the next year's rendezvous. (They just raised the engine's safety threshold setting for the next thrust.)
Also of note, the NEAR probe was renamed the NEAR-Shoemaker probe, after the late Dr. Eugene Shoemaker, a leading asteroid research pioneer who died in 1997 in an automobile accident while visiting impact craters in the Australian outback.
Eros is one of the largest near Earth asteroids. Yet, its escape velocity is only about 22 miles per hour (35 kilometers per hour), i.e., a child could easily throw a rock off of it. Eros is an S-type asteroid with composition varying over its surface, and a rotation rate of 5.27 hours.
En route to Eros, NEAR did a close flyby of the asteroid Mathilde on June 27, 1997, pictured on the next page.
Mathilde has a maximum diameter of 53 kilometers (33 miles) which made it the largest asteroid visited by a spacecraft. A one ton object on Earth would weigh the same as 2 kilograms (4 pounds) on this asteroid. It also has an unusually long period of rotation, at 17.5 Earth days. The closest approach was around 1200 km (750 miles) which was the closest approach to an asteroid made by any spacecraft to date.
Mathilde is one of the darkest asteroids we know of, reflecting only 3% of sunlight. It is twice as dark as charcoal. It is a C-class asteroid and thought to be very rich in carbon. Its density is roughly that of ice, which is about half the density scientists had expected before the encounter. Its color is extremely uniform, and the density of craters indicates its surface has been exposed for several billion years. This indicates it was never part of a large parent body which underwent gravitational differentiation. Scientists find it amazing that Mathilde is still intact after such huge impacts. It's almost more crater than body space. Also remarkable is its uniformity in composition, judging from its lack of color variation.
Mathilde is pictured above, the largest crater is more than half the width of the asteroid and 5 kilometers (3 miles) deep.
The NEAR probe manufacturer has a webpage on the Mathilde encounter.
Mathilde is not very economically attractive due to its distance and the energy that would be required to land on it, even though it seems to be volatile rich.
On the other hand, Eros is economically accessible from a transportation standpoint, but Eros is not very attractive in terms of what it's made of. While we really don't know very well what it's made of, even after NEAR's visit, we do know in general that Eros is a bright, rocky body that is probably poor in volatiles, though we really don't know what's under the uniform surface. Its material is twice the density of Mathilde's. It apparently formed in the inner solar system (not a captured comet), is made of primitive materials, is fairly uniform (undifferentiated, chipped off of a body that did not separate into core, mantle and crust), has not suffered catastrophic collisions, hasn't melted, and is consolidated in that it's held intact by its internal material strength. (In contrast, many asteroids are thought to be rubble piles from impacts, and others are burnt out comets with a sealing crust.) Eros is like a soft rock that's cracked but not broken. Lots of grooves and cracks, but intact.
We know the surface composition, but not the subsurface. However, in places where there has been recent shifting of material, such as on cliffs, the underlying material is brighter. It is an ordinary chondrite consisting of both heavy and light materials, never subjected to intense heating.
The home page for NEAR tells everything, at near.jhuapl.edu.
§ 1.5.2 Present probes
Deep Space 1 Probe
The Deep Space 1 (DS1) probe, launched on October 24, 1998, had as its declared objective "To test 12 advanced technologies in deep space to lower the cost and risk to future science-driven missions that use them for the first time." This includes using a very fuel-efficient electric ion-drive propulsion system for all its propulsion needs, once launched out into space.
As a "bonus", the Deep Space 1 mission was "extended" to make a very close asteroid fly-by, specifically of asteroid "1992 KD", subsequently renamed "9969 Braille", at a distance of only 10 kilometers in July, 1999. Emphasis was made that the mission was already entirely successful without any target flybys, and any and all asteroid and comet flybys were extra.
When the asteroid encounter occurred, no good pictures were taken, partly due to the asteroid being darker than the worst-case scenario envisioned (surface high in carbon?), and then a software bug which caused the failure of the target tracking system and a "safe mode". The best photo was just 4 pixels, from 70 minutes prior to the flyby. The "safe mode" caused a time dropout. After that, in all subsequent photo attempts, the camera was pointed in the wrong direction.
(The probe was programmed to essentially shut down and call Earth if it encountered that kind of bug, i.e., "safe mode". It was an inconvenient time -- during a rendezvous. The probe team had to hurriedly reset the probe. Perhaps it should have just reset and continued, with reporting as it goes, and reasonable limitations on behavior. Yes, this sounds a lot like Clementine's failure en route to Earth-crossing asteroid Geographos.)
"Braille" thus was a prophetic name for this asteroid.
However, the infrared camera functioned OK and the highlighted infrared image is at http://neo.jpl.nasa.gov/images/braille.gif.
That September, the mission was officially "extended" again, beyond the first budget allocation.
The next scheduled target was asteroid/Comet Wilson-Harrington a year and a half later. This is a very interesting object because it was seen as a captured comet with a tail in 1949, then "lost". Subsequently, an asteroid was discovered in 1979. Years later, someone backtracked the asteroid's orbit and realized that the asteroid was the comet, but without the tail. Thus, it became the first (and only, to date) comet seen to become an asteroid - a "transitionary" object. This lent further support to the mathematical models which state that many, if not most, asteroids near Earth are captured comets, and probably are very volatile rich under a thin crust.
Thus, many professionals were greatly excited about the Comet Wilson-Harrington encounter, far more so than the asteroid Braille.
The bugs in the pointing system were worked out in transit.
Unfortunately, in November 1999, the star tracker of Deep Space 1 failed. The spacecraft entered a "safe mode" whereby it shut down the propulsion system. Without the star tracker, engineers had to devise alternative ways of pointing and controlling the spacecraft, a very challenging task. A improvised, best-we-can-do system was implemented in December and January, and the spacecraft was deemed to still have some useful life.
The encounter with Comet Wilson-Harrington was missed due to the down time of the spacecraft.
The star tracker was not one of the 12 technologies to be tested, but was an advanced subsystem which had experienced intermittent problems earlier in the mission, and finally failed totally that November.
The next target is Comet Boreally in September, 2001. It will make a difficult pass through the comet's tail, taking measurements of the composition of the tail and trying to get a good picture of the core. Getting a good picture will be very technically challenging due to the failure of the star tracker.
If we get any photos out of Deep Space 1, they will be of Comet Boreally.
The relevance to PERMANENT is low, of any photos and data regarding the Comet Boreally.
Further information is at http://nmp.jpl.nasa.gov/ds1.
However, the official website is not designed to give you the quick scoop on the mission, especially its failures in regard to the asteroid flybys. The news is just too roundabout and politically longwinded, with the bad news hidden and smoothed over. Out of all the files on the site, you must hunt down the files with an apparent date around the encounter with Braille in July 1999, and then again in November 1999. Those documents keep starting by saying that it's a completely successful mission because all 12 of its experimental technologies worked well (so they can be used in future private or public sector missions) -- something you get tired of reading over and over -- especially before they verbally deal with the photo failures as best they can. It's the style that I find irritating. Of course, most taxpayers not only want to see the photos but also want to know what's new and going on without having to dig and dig for that information! They could have made it a lot quicker and easier. For example, I could find only one place where they announce that the rendezvous with Comet Wilson-Harrington was ever aborted, deep down in a technical document, though they word it by saying that another comet (Boreally) is now the only one "selected". It would be quite forgivable if they'd just say it like it is rather than try to brush things under the carpet with incessant spin.
Some of the technologies tested included an autonomous navigation system using the star tracker, a Miniature Integrated Camera Spectrometer (MICAS), "SCARLET" solar arrays, and a small deep space transponder. Total cost of mission (1995-99) was $152.3 million, all inclusive, and the extended part should be relatively little.
Understand: It was a completely successful mission in testing the 12 new technologies in space, and the failures were in the bonus photos, the non-flyby of transitionary object Wilson-Harrington, but most of all their style in announcing the bad news. To their credit, the technical paper on the DS1 website regarding the extended mission is a fascinating, indeed riveting, blow-by-blow account of the mission, its difficulties, successes ... and failures in the extra events (worded more carefully than this).
§ 1.5.3 Future and proposed probes
Muses-C -- Japanese Sample Return Mission
Muses-C is the most interesting and relevant mission on the immediate horizon for PERMANENT.
Muses-C will return a sample of an near-Earth asteroid to a laboratory on Earth. Timeline:
- July 2002 -- launch
- October 2003 -- arrive at asteroid 1989ML, start studying the asteroid
- April 2004 -- take a sample, send it on a trajectory back towards Earth
- June 2006 -- re-entry vehicle with sample arrives on Earth
Muses-C will also land two surface vehicles, a microrover from the U.S. JPL and a hopper from Japan's ISAS.
This 500 kg Japanese probe will launch on a Japanese M-V launch vehicle, and use ion drive propulsion for the interorbital flight. The re-entry vehicle will undergo a far more stressful return than Apollo or the Space Shuttle, coming in from deep space. Muses-C follows the successful Muses-A (lunar orbiter) and Muses-B (radio astronomy satellite) missions.
Older reports on Muses-C had the probe going to the asteroid 4660 Nereus. However, the target was changed to 1989ML, which is thought to be an ordinary primitive body, based on the unchanging spectra obtained by telescopes. The likelihood of 1989ML being an attractive target for PERMANENT is thus reduced.
(The previously targeted asteroid, Nereus, looks different and may be a captured comet, which would make Nereus more attractive to PERMANENT. SpaceDev (below) may go after Nereus, and there have been other groups interested in Nereus. Nereus is also one of the quickest and most economical near-Earth objects to reach.)
Details on the Muses-C mission can be obtained at
www.muses-c.isas.ac.jp/English/index.html
Asteroid Nereus and SpaceDev's NEAP (private Near Earth Asteroid Prospector)
SpaceDev LLC embarked on an effort to send a private sector probe to an asteroid, with the most likely candidate being 4660 Nereus. Due to difficulties in raising money, they missed their first ambitiously announced launch date (on a Russian launcher), but other business has taken off well, and SpaceDev has now switched to a smaller microsatellite design, launched from the Ariane as a secondary payload, possibly as early as January 2002 for a rendezvous with asteroid Nereus six months later. More information on this project will go up in Chapter 8, Mission Plans and Concepts, but you should rely first on the SpaceDev website for accurate and current information, in their Missions section.
Clementine 2
Clementine 2, a joint venture between the U.S. Air Force Space Warfare Center, Phillips Laboratory and NASA, is intended to rendezvous with a number of near-Earth asteroids and characterize each via probe impact. Little information has been forthcoming on this project, but it is reportedly being funded. (paper reference) Targets being considered include asteroids 1987 OA, 1989 UR, and 1991 JX. Objectives include analyzing the dynamic strength of surface material, crater formation, dust cloud composition, stratification, thermal properties, and of course spectral data for composition and mechanical properties. Clementine 2 follows the now famous past probe Clementine 1 which discovered ice at a lunar pole.
In 1997, when the controversial U.S. President's "line item veto" was first exercised, one of the first things cut was the mere $20 million annual appropriation for Clementine 2. This reflected gross lack of leadership on the part of President Clinton and his top advisors. After all, Clementine 1 had just made the discovery that water ice exists on the Moon. It's also appauling given the uncounted billions we spend on military defense to defend the remaining exhaustible resources around the world. They cut the way out of the limited resources of Earth, just over hardheaded old conservatism. That's not good leadership. You're encouraged to politically support Clementine 2 any appropriate way you can.
NEARS and 4660 Nereus
A detailed 792 kg spacecraft design for a sample return mission to the near Earth asteroid 4660 Nereus was proposed by researchers at the Johns Hopkins Univ. Applied Physics Laboratory (JHU/APL) by many of the same people involved in NEAR above. (It is the same laboratory involved in many defense and civilian missions.) At the asteroid, an Earth return capsule would detach from the spacecraft with a "six-shooter" sampling device. Samples can be taken from rock or regolith. As the name implies, six samples would be taken. When the vehicle returns to low Earth orbit, the samples separate from the vehicle and parachute to Earth. On a budget trajectory, the round trip time is 4 years.
A good detailed account of this NEARS (Near Earth Asteroid Return Sample) proposal was given at a Princeton conference (paper reference).
4660 Nereus is a near-earth asteroid which is believed to be one of the most primitive asteroids in the solar system. It is definitely not a rocky asteroid, but is believed to be primitive C-type, perhaps rich in volatiles, and possibly a captured comet. It is about 1 km wide in an orbit that crosses Earth's orbit, and is economically fairly attractive.
Japanese 4660 Nereus mission
The Japanese ISAS is planning to launch a probe to rendezvous with the asteroid 4660 Nereus and return a sample to Earth. The mission is being developed for the year 2001. Not much information is available on the WWW yet on this mission. Good contact people on this mission include Jun'ichiro Kawaguchi, Akira Fujiwara and Kuninori Uesugi of the ISAS.
The Japanese ISAS and the JHU/APL people are not the only two to take primary interest in 4660 Nereus. SpaceDev's NEAP probe might also be targetted for Nereus.
US Stardust probe -- comet sample return mission
The Stardust probe was originally proposed for launch in February 1999 for rendezvous with comet P/Wild 2 in January 2004, to collect data of many kinds on the comet, collect material for return to Earth, and deliver the comet samples to Earth in January 2006. I haven't kept up with this one. Since there's been little word on this mission for a long time, it has probably not been given any more funding to go forward. However, the probe's paper design may be interesting.
Rosetta, Mimistrobell and Shipka
The European Space Agency is planning to launch the probe Rosetta in 2003, which will rendezvous with the comet Wirtanen in the year 2011 and release two landers to perform on-site analysis of its surface. The long delay between launch and rendezvous is largely due to the need to get multiple gravity assists from Mars and the Earth over a period of years in order to save on fuel propellant launch costs and maintain a small budget.
This probe will also fly by two asteroids on the way to the comet -- the main belt asteroid 3840 Mimistrobell and the asteroid 2530 Shipka.
Neither of these objects are of interest for materials utilization for space industrialization, though the scientific data will be interesting in a more general sense. But by that time, we should be visiting near Earth asteroids for materials utilization already. The timeframe 2003 to 2011 seems a long way away for me, but I'm sure it's not for the Europeans involved in the mission.
The equipment being designed on paper today for this future mission to take the samples and return them is interesting. There is a list of the scientific equipment to be put on the Rosetta spacecraft at the Rosetta internet reference above, and its designers could be good people to help design probes for near Earth asteroids before then...
§ 1.5.4 Surface Lander Technologies
The previous section lists several planned and proposed probes with designs for surface samplers. A company interested in designing a probe can contact the sources and get that public domain, taxpayer funded information.
This section discusses some of the technologies and issues involved with asteroid surface landers, as well as sources of information in addition to the probes above.
Russian Phobos probes
The Russians sent two missions to Mars' asteroidal moon Phobos in the 1980s with microgravity robot landers. The landers were designed to move around the surface of Phobos by hopping, without any fuel propellant, just rotating legs. However, both probes failed before the robotic landers arrived at the asteroid. One lost communication en route to Mars, and the other lost communication at Phobos. The latter is believed to have possibly suffered a fuel propellant explosion during a close-in maneuver.
Some of the recent Russian literature on asteroid missions is written by V.A. Simonenko and his colleagues, e.g., paper references 1, 2, and 3.
Attachment techniques in microgravity
One of the main challenges of dealing with an asteroid, whether it be probes or mining, is working in the microgravity environment. We have little experience in this. Once we gain some experimental experience, we will develop some routine techniques, and the first to gain experience will get some valuable patents. However, we have very little experience in microgravity to date, especially as regards something like an asteroid.
So far, the alternatives considered by various studies for surface attachment and mobility on, in and around an asteroid are:
- Just relying on the microgravity and moving around ballistically ("hoppers"), by wheels or by crawling using a claw device (the claw in turn having many potential designs...)
- Attaching a net and moving around along its cables
- One penetrator attachment, and moving around by rigid crane, or ballistically by tether and winch
- Two penetrator attachments with two loose tethers and winches, and move from location to location by moving one of the penetrators at a time
- Three penetrator attachments with winches, holding device tightly down to the asteroid by tension of three cables
- Using propellant to fly around from spot to spot
- Magnetic attachment (iron rich asteroid)
- Tunnelling in and pushing against opposite walls for wheels, treads or crawling
Penetrator attachments can be one or more of the following:
- Simple spike
- Harpoon with retractable catch
- Screw device - helical drill
MIT study on asteroid surface probe
The MIT Artificial Intelligence Laboratory has developed small, low mass robots and analyzed how they could be adapted to an asteroid environment. As in the Russian designs, hopping was adopted. The final design looks like a flat insect with six legs. Included in the MIT study were momentum wheels used to aid in stability during motion over the surface, and solar panels which could be cleaned of dust ("grooming"). Close attention was paid to joints sealed from dust and thermal management. (To keep out dust, it seems to me that a baloon type of ball joint is simple enough and this should be no such drama.) It was estimated this robot could completely scope out a 2 kilometer diameter asteroid in about 125 days. (reference).
In addition to hopping, the claws of the robot could be designed to give the probe the capability to operate much like a rock climber in case the asteroid has a hard surface. One option they considered is to mimic an insect's legs, which have hooks capable of latching onto surface irregularities, which is what allows insects to walk across ceilings, or latching into fairly cohesive soil.
A fairly generic robot with a combination of transport capabilities would be able to adapt to different asteroids' environments as well as different environments on the same asteroid. Such a multifaceted design could result in standard asteroid robot capable of dealing with a wide range of conditions, without any need for another probe to go scope out the asteroid environment prior to sending the surface probe.
Due to the low mass of asteroid robots, several robots could be sent on the same mission to an asteroid using a small rocket. Thus, it may also be feasible to send more than one kind of robot on a given scouting mission.
SKITs - laboratory work by SSI, USC and JPL
The most interesting current work as of this writing on asteroid probes is being conducted jointly by the Space Studies Institute (SSI), the University of Southern California (USC), and the Jet Propulsion Lab (JPL). The researchers are pursuing a concept of deploying multiple, very small telerobots (e.g., 1 kg) called Sub-Kilogram Intelligent Tele-robots or "SKITs" to the surface of an asteroid. The mother craft would continue orbiting the asteroid and would serve as the communications relay to Earth. The research is attempting to produce substantial results in 1 years' time, using hardware/software simulation studies and taking advantage of new technology in the areas of robotics, artificial intelligence and communications.
Several experimental SKITs have already been built and tested in the laboratory.
"A typical scenario for this research would be to release a number of vehicles with some communication capability, and with a specialization of functions on a simulated landscape. Humans would control the overall deployment policy but the telerobots would have some autonomy to deal with obstacles….
"Our intent was to develop a research program involving actual hardware development to produce prototypes of intelligent miniature tele-robots that could later be improved, space-qualified and used in precursor missions for space resource prospecting, mining and manufacturing. In addition we focused our attention on the effective utilization of the abundant and rich untapped resources of asteroids…
"Our plan was to study the relative merits of miniature size robots, with various degrees of intelligence for the initial phase of this process… The leverage these [size and weight] constraints may provide are substantial benefits in the areas of reliability, high coverage and low cost…
"The primary prospecting objectives for asteroids are surface imagery and a detailed determination of their composition. These diagnostic elements should be measured with sufficient global coverage to determine the scale and extent of chemical heterogeneity. In addition, in order to get samples that are pristine, a drill or some similar tool will be needed."
The study did not try to come up with one recommended probe set, but rather to come up with concrete design alternatives which a prospector could choose from, depending upon the prospector's objectives, budget and other judgement factors. Tradeoff analyses are a main part of this research.
However, one concept researched in greater depth was a group of SKITs that are attached to a net which in turn is attached to the asteroid. A base is formed at one place on the net. The net serves more than one purpose:
- The net provides anchoring and mobility
- The net provides wired communications between SKITs and the net base
- The net provides power to the SKITs from the net base (e.g., solar power plant and rechargable batteries)
- The net serves as a large antenna for communications to the orbiting craft, as well as to Earth - a bigger antenna means better two-way communications with Earth
The net can be small and anchored over one region, or it can be large and wrap around the asteroid. The net can consist of parallel and perpendicular cables - a square pattern, or it can consist of circular concentric rings.
There were many kinds of SKITs conceived, and some built. The SKITs could be divided into three kinds of units:
- Home base units - performing centralized functions on the net such as Earth communications, computerized control and analysis, tool storage, battery recharging, non-mobile instruments (e.g., for material analysis), etc. - not mobile in daily operations, but movable
- Mobile workers -- performing prospecting and asteroid material handling tasks - mobile but really geared for the more sophisticated work in the trenches
- Mobile helpers -- assisting the mobile workers by shuttling tools and instruments between the base and the workers in the trenches, as well as samples back to non-mobile analysis equipment at the base, as well as deploying and positioning the net and its anchors - the most mobile SKITs
There are obvious variations of the above three kinds of units, especially breakouts among the latter two. How specialized or modular the SKITs may be is up to the design choice of the mission planner.
An impressive, complete setup of SKITs was demonstrated by the researchers in May 1997 at the Space Studies Institute's (SSI) Conference on Space Manufacturing XXIII in Princeton, New Jersey, using a base unit and several SKITs, each robot being a little smaller than an average coffee cup, as pictured here.
Pictures of SKITs, and a Mobile Helper at a Base Station (bottom right)
Payloads for probes
Desired data include asteroid size, shape, mass, gravity, spin state, elemental and mineral composition, texture, and variations in composition and texture in different places on the asteroid.
The kinds of payloads considered for probes include:
- Imager (CCD camera)
- Gamma ray, neutron and X-ray spectrometers (to determine composition)
- Infra-red (IR), NIR and visible spectrometers (to determine composition)
- Magnetometer
- Seismic analyzers (to try to determine internal structure by induced shock waves)
- Drilling device
- Sample collector analyzer
- Mass spectrometer (to determine composition)
Most of these instruments have been used in probes before and thus could be considered practically flight ready.
REGA - NASA JSC
The NASA Johnson Space Center (JSC) is developing a flight instrument for probes to measure volatiles in samples of regolith "[f]or bodies such as the Moon or asteroids". It consists of a small programmable furnace which can measure volatiles released at different temperatures, a supply of reactant gas, and a quadrupole trap mass spectrometer. It is a small instrument.
Technical parameters:
- Size: 15 x 20 x 27 cm - less than 0.03 cubic meters (6 x 8 x 11 inches)
- Mass: less than 5 kg (12 pounds)
- Power: less than 50 watts
- Soil sample size: 1 gram
- Maximum oven temperature: 900 C
"During 1994-95 we accomplished the following:
- Completed laboratory studies of lunar soil reactivity
- Completed oxygen release experiments in prototype REGA sample containers
- Completed thermal modeling of the sample container to optimize furnace design
- Finalized furnace and gas system designs and commenced fabrication
- Fabricated a 1:1 volumetric mockup for integration
"During 1996 we are conducting verification and calibration tests on the furnace and gas distribution systems. We will integrate these two systems with a quadruple mass spectrometer to be provided by University of Texas at Dallas. This instrument is modified from the mass spectrometer which flew on the Shuttle Wake Shield Facility during the summer of 1995. We will then perform a series of tests to determine the background, sensitivity, and performance of the integrated REGA.
The mockup is designed to contain and insulate the full suite of REGA components and instrumentation. Dimensions are 15cm x 20cm x 27cm (5.9" x 7.9" x 10.6")
"Future work will build on the results of these tests. We will define the instrument's control, data and communication requirements and commence design of this system. We will fabricate an integrated prototype with its control and data system and conduct verification testing in a vacuum chamber. To complete this project we intend to bring REGA to a flight-ready status. " (paper reference).
Probes
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