Shuttle Launch Delayed Until January 2

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Space shuttle Atlantis’ STS-122 mission to the International Space Station has been further delayed and now is targeted to launch no earlier than Jan. 2. The liftoff date hinges on the resolution of a repeat failure of the shuttle’s fuel sensor system. NASA has not yet made a final decision if repairs to the system will be done on the launch pad or if Atlantis will need to be rolled back to the Vehicle Assembly Building where the external tank can be removed.

“It would depend on what we find…but we have a lot of options in front of us,� said NASA’s Mission Management Team chairman LeRoy Cain at Sunday morning press briefing. Cain added that if they do decide to roll back, that probably would not support a January 2 launch. However, STS-122 Launch Director Doug Lyons said he couldn’t envision a scenario that would necessitate a rollback. “We have almost limitless access (to the tank) and there are not many things we can’t do on the launch pad that we could do at the VAB.�

Early Sunday, one of the four engine cutoff (ECO) sensors inside the liquid hydrogen section of Atlantis’ external fuel tank gave a false reading while the tank was being filled. NASA’s new and updated Launch Commit Criteria require that all four sensors function properly. Following Friday’s launch scrub, the MMT decided to shorten the launch window to one minute in an effort to work around the sensor problem. Upon launch, this would send the shuttle on a direct trajectory to the space station, and would save fuel. Fuel depletion is what drives the need for the ECO sensors which protect the shuttle’s main engines by triggering engine shut down if fuel runs unexpectedly low. But the MMT also added the criteria that a failure of any of the four sensors would prompt a launch scrub.

Previously, the criteria required that three of the four sensors had to function properly. Atlantis’ scheduled launch on Thursday, Dec. 6, was delayed after two liquid hydrogen ECO sensors gave false readings. A third sensor gave a false reading while the tank was being emptied.

Meanwhile, ISS flight controllers informed space station commander Peggy Whitson that she and crewmate Dan Tani likely will be asked to carry out a spacewalk later this month to inspect a problematic solar array rotary joint on the right side of the lab’s main power truss. If the launch of STS-122 had gone as planned, a team of shuttle astronauts would have conducted the inspection.
The crew of STS-122 will come out of quarantine and return to Houston.

The main objective of Atlantis’ mission is to deliver, install and activate the European Space Agency’s Columbus laboratory, which will provide scientists around the world the ability to conduct a variety of life, physical and materials science experiments.

Following STS-122, the next two flights on the shuttle manifest for space station construction are scheduled for launch in mid February and late April. The next flight after that is an August mission to service the Hubble Space Telescope. Bill Gerstenmaier, Associate Administrator of spaceflight operations at NASA said that this delay shouldn’t affect NASA’s ability to complete station construction before the shuttle is scheduled to be retired in 2010. “This doesn’t impact the overall manifest. With the remaining time we can accomplish all the flights,� Gerstenmaier said.

Original News Source: NASA TV

Shuttle Launch No Earlier Than Saturday

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The crew of STS-122 and the Columbus science module will have to wait a little longer for their ride to space. The launch of space shuttle Atlantis has been pushed back to no earlier than Saturday, December 8. After assessing the problem with the engine cutoff sensors that scrubbed Thursday’s scheduled liftoff, NASA’s Mission Management Team decided they needed more time to look at the problem. But even a Saturday launch is a best-case scenario, and further delays loom as a possibility.

Engineers continue to examine the circuitry and NASA will hold a briefing at 5 pm EST today to announce when another launch will be attempted. A Saturday launch would be at 3:43 pm and Sunday at 3:20 pm EST. The forecast for Saturday calls for a 60 percent chance of good weather, improving to 70 percent on Sunday.

Based on data received during fueling on Thursday, engineers believe the problem may involve an open circuit between the sensors in the hydrogen portion of the external fuel tank and an electronic box in the shuttle main engine compartment. Two of four sensors failed in a test that is routinely done during tanking. The fuel cutoff sensor system is one of several that protect the shuttle’s main engines by triggering their shut down if fuel runs unexpectedly low. Launch Commit Criteria require that three of the four sensor systems function properly before liftoff. The sensors also gave another false reading while the tank was being emptied, but are now currently indicating correctly the tank is dry.

The current launch window closes on December 13. If the shuttle can’t launch before then, the next earliest launch date wouldn’t be until January 2. While NASA officials initially said they would try to launch today, after a five hour meeting the Mission Management Team decided to hold off for another day. “We need more time,â€? said LeRoy Cain, Chairman of the MMT. “This (problem) is a little bit new, so we want to sleep on it. I can almost guarantee you we will have some new thinking after we let this team go home and rest.”

Since engineers think the problem lies in an open circuit, currently, NASA doesn’t believe any major repairs in hardware will need to be done, which would cause a longer delay for the launch.

“We’re still hoping, and have reason to believe, that we’re going to get off in December,” said Doug Lyons, NASA’s shuttle launch director, “and that’s what we’re shooting for.”

Atlantis will carry the crew of STS-122 to the International Space Station to deliver the Columbus Science Module. Columbus is the European Space Agency’s major contribution the ISS.

Officials from the ESA were disappointed in the delays, but said that safety is most important. “This is perfectly normal,” said Alan Thirkettle, the ESA’s space station program manager, of the launch delay. “We want to launch on time, but we want to launch right.”

Original News Source: NASA TV

Shuttle Launch Postponed

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A problem with space shuttle Atlantis’ fuel sensors has prompted a scrub of today’s scheduled launch of the STS-122 mission to the International Space Station. During fueling of the shuttle’s external tank, two of four engine cutoff sensors failed. Engineers are working on fixing the problem and NASA will try to launch again tomorrow, Friday, December 7 at 4:09 pm EST.

Sensors located in the hydrogen portion of the tank “failed wet” during fuel loading this morning. That means the sensors could falsely indicate the tank still contains hydrogen in the last stages of the shuttle’s climb to space when it actually is empty. The engines would continue to run, and without fuel, the engines could ignite and explode.

Problems with the engine cutoff sensors have occurred before during tanking, including the first shuttle mission after the Columbia accident, STS-114 with space shuttle Discovery. The failed sensors caused a one-day delay in the launch and after the flight the problem was traced to a faulty connection in electrical cables. NASA hopes that in emptying the tank and then refueling tomorrow the sensors will reset correctly, as was the case with the STS-114 launch.

This shuttle mission, STS-122, will bring the Columbus science module to the ISS. Columbus is the European Space Agency’s cornerstone contribution to the space station. Two ESA astronauts, Hans Schlegel from Germany, and Leopold Eyharts from France, are part of the shuttle crew, and Eyharts will remain on board the station to lead the activation of the new lab. The other astronauts for the mission are Commander Stephen Frick, pilot Alan Poindexter and mission specialists Rex Walheim, Stanley Love, and Leland Melvin.

STS-122 is expected to be an 11 day mission. It is the 121st shuttle flight and the 24th mission to the ISS.

Original News Source: NASA TV

‘Tis the Season to Explore the North Pole on the Moon

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Mention the North Pole this time of year and perhaps what comes to mind are visions of snowy, candy cane-lined streets leading to a candle-lit workshop. But how about sun-drenched regolith dotted with craters cast in permanent shadows? Those are the types of images revealed in a new detailed map of the north pole — on the moon.

A mosaic created from data obtained by the SMART-1 spacecraft shows detailed features of the geography and illumination of the lunar north pole. These maps can be used by future explorers as an aid for traveling and traversing on the moon.

The lunar poles are of interest for science and the upcoming exploration of the moon mainly because of their exposure to sunlight. There are areas that are continually bathed in sunlight, but within craters in the same region are dark areas that rarely receive any light, and therefore could contain water ice. Both these aspects would be important for potential lunar base sites.

“Solar illumination makes these areas ideal for robotic outposts or lunar bases making use of solar power, ” said the European Space Agency’s Bernard Foing, who is Project Scientist for the SMART-1 Spacecraft.

Any water ice on the moon would be useful for the inhabitants of a lunar base.

The SMART-1 north pole map covers an area of about 800 by 600 km and shows the geographical locations of several craters. Of special interest is Peary Crater, the largest impact crater that is close to the lunar north pole. At this latitude the interior of the crater receives little sunlight, but SMART-1 was able to observe it during phases when the crater floor was sufficiently illuminated for imaging.

Also imaged was Crater Plaskett, located on the northern far side of the moon, about 200 kilometers from the north pole. Because of the location of this crater it receives sunlight at a low angle and it has been suggested as a lunar base that could be used for a possible analog to simulate conditions of a manned mission to Mars.

Foing also said that the discovery of water ice on the moon could help us understand Earth’s history as well. “If the layers of ice come from the volatiles deposited by comets or water-rich asteroids, we could better understand how, and how much, water and organic material was delivered to Earth over its history,” he said.

Using electric propulsion navigation, SMART-1 reached lunar orbit in November of 2004 and performed a year and a half of scienctific observations. The mission ended with a controlled impact on the moon’s surface in September of 2006.

The polar mosaics were presented and discussed at the 9th International Lunar Exploration Working Group (ILEWG) lunar conference in October 2007.

SMART-1 science investigations include studies of the chemical composition of the Moon, of geophysical processes such as volcanism, tectonics, cratering, and erosion, and high resolution studies in preparation for future steps of lunar exploration.

Original News Source: ESA Press Release

Columbus to Set Sail for Space

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For European scientists and space enthusiasts, the wait will soon be over. The Columbus module, the European Space Agency’s (ESA) major component for the International Space Station, will finally be delivered to the ISS aboard space shuttle Atlantis on STS-122. The launch is scheduled for Thursday, December 6, 2007 at 4:31 pm EST. Flying along with Columbus are two ESA astronauts, Hans Schlegel from Germany, and Leopold Eyharts from France.

The ESA considers Columbus as the most important European mission to the ISS to date and the cornerstone of Europe’s contribution to this cooperative international endeavor.

Creating a human-capable science module for a space station was first proposed by Europeans back in 1985. At that time France was considering building a mini space shuttle called Hermes to fly to a proposed space station called the Man Tended Free Flyer (MTFF) to be built by Germany and Italy. But with the postponement of MTFF in 1991 and the termination of Hermes in 1993, the planned Columbus module was left with no ride to space and nowhere to go.

When the ESA joined as an ISS partner in 1995, the Columbus science module was a logical contribution for the Europeans. The module was completed in 2000, and the original date for delivery of Columbus to orbit was 2004. But that date was pushed back following the Columbia space shuttle accident in 2003.

Columbus is 7 meters (23 feet) long and 4.5 meters (15 feet) in diameter and will hold specialized experiments for multidisciplinary research into biology, physiology, material science, fluid physics, technology, life science and education. Columbus can hold ten science racks, but will launch with only five in place, as future missions will bring more science racks on board. Additionally, there are two stands bolted to the outside of the module that can be used for research on materials and for unfiltered views of space. Columbus will be attached to the Harmony node’s starboard docking port.

Schlegel will play a key role in two of the three spacewalks or EVA (Extra-Vehicular Activity) scheduled for the mission, helping to install and power up the laboratory.

Eyharts will stay aboard the ISS for a long duration mission, replacing Dan Tani who will return to Earth on the shuttle. Eyharts will play a key part in the installation, activation and in-orbit commissioning of Columbus and its experimental facilities.

Once in orbit, Columbus will be monitored from ESA’s Columbus Control Centre located within DLR’s German Space Operations Centre in Oberpfaffenhofen, near Munich.

The American astronauts on Atlantis are Commander Stephen Frick, pilot Alan Poindexter and mission specialists Rex Walheim, Stanley Love, and Leland Melvin.

The forecast for Thursday’s launch is 80 percent “go,” decreasing to 60 percent on Friday and Saturday.

Original News Source: ESA Press Release

NASA’s New Look

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NASA unveiled a new look for its website over the weekend, and hopes that blogs, interactive features, and a customizable layout will especially appeal to 18-25 year olds.

A New York Times article reported that NASA is concerned that the social networking generation hasn’t shown enough interest in NASA, and the space agency hopes their new webpage will attract the MySpace crowd. This is the first major overhaul for NASA’s website since 2003, and NASA now hopes to compete with Space.com and CNN’s more chic presentations of space exploration. Numerous rollovers, links, and spectacular graphics can keep a visitor engaged for quite awhile, and readers can now Digg, del.icio.us or StumbleUpon stories that they like or want to share. The “Image of the Day” Gallery also benefited with a much-needed upgrade.

Critical Mass, the company that assisted NASA with the new design, says on their website that NASA’s site will now “inspire, involve and inform” and will unify over 3,500 different sites into a “cohesive information gateway.”

One past criticism of the different NASA webpages is that there was sometimes redundant or conflicting information. Critical Mass and their partner eTouch Systems claim the new site will fuel NASA’s efforts to “reconnect with the public and re-capture significance as one of the world’s most visionary and imaginative organizations.”

Still, Brian Dunbar, Internet Services Manager for NASA estimates that even before the overhaul, NASA’s website received approximately one million unique visitors each month. Not bad for an aging, old-fashioned, 50-year old.

Chime in with your thoughts about NASA’s revamped webpage on the BAUT Forum.

Original Source: New York Times

Meteorites Reveal Mars’ Past: Molten Surface, Thick Atmosphere

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If Mars ever had water flowing on its surface, as the many canyons and riverbed-like features on the Red Planet seem to indicate, it also would have needed a thicker atmosphere than what encircles that planet today. New research has revealed that Mars did indeed have a thick atmosphere for about 100 million years after the planet was formed. But the only thing flowing on Mars’ surface at that time was an ocean of molten rock.

A study of Martian meteorites found on Earth shows that Mars had a magma ocean for millions of years, which is surprisingly long, according to Qing-Zhu Yin, assistant professor of geology at the University of California- Davis. For such a persistent event, a thick atmosphere had to blanket Mars to allow the planet to cool slowly.

Meteorites called shergottites were studied to document volcanic activities on Mars between 470 million and 165 million years ago. These rocks were later thrown out of Mars’ gravity field by asteroid impacts and delivered to Earth — a free “sample return mission” as the scientists called it — accomplished by nature.

By precisely measuring the ratios of different isotopes of neodymium and samarium, the researchers could measure the age of the meteorites, and then use them to work out what the crust of Mars was like billions of years before that. Previous estimates for how long the surface remained molten ranged from thousands of years to several hundred million years.

The research was conducted by the Lunar and Planetary Institute, UC Davis and the Johnson Space Center.

Planets form by dust and rocks coming together to form planetisimals, and then these small planets collide together to form larger planets. The giant collisions in this final phase would release huge amounts of energy with nowhere to go except back into the new planet. The rock would turn to molten magma and heavy metals would sink to the core of the planet, releasing additional energy. The molten mantle eventually cools to form a solid crust on the surface.

Although Mars appears to no longer be volcanically active, NASA’s Mars Global Surveyor Spacecraft discovered that the Red Planet hasn’t completely cooled since its formation 4.5 billion years ago. Data from MGS in 2003 indicated that Mars’ core is made either of entirely liquid iron, or it has a solid iron center surrounded by molten iron.

Original News Source: UC Davis Press Release

NASA Tests New Parachutes for Ares Spacecraft

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This has been an exciting week for NASA’s Constellation program — the missions that will bring humans back to the Moon. Earlier in the week, NASA announced plans for testing abort systems and inflatable Moon habitats.

But on Thursday, November 15 actual tests were conducted for some of the genuine hardware that will be used for the Ares launch vehicles.

Near Yuma, Arizona, engineers tested the parachutes that will bring boosters from the first stage of the massive Ares rockets back to Earth.

Certainly, parachutes and rocket booster recovery is nothing new for NASA. But this new parachute is a whopper. Spanning 150 feet across and weighing 2,000 pounds makes this the largest chute of its kind ever tested for parachutes that will carry some of the heaviest payloads ever delivered.

And the new parachute worked perfectly — if not patriotically — with its red, white and blue striped canopy. Made of Kevlar, which is stronger and lighter than the nylon chutes used for the space shuttle’s solid rocket booster recovery, these bigger and stronger parachutes can still fit into the same size canister used for the shuttle boosters but yet be lighter.

Although the Ares boosters will actually come down in the Atlantic Ocean, the tests were conducted in the desert near the U.S. Army’s Yuma Proving Ground. Additionally, the tests used only a 42,000 pound weighted tub as opposed to the 200,000 pound weight of the actual boosters. But the drop tests from 16,000 ft. from a C-17 airplane simulated the peak loads at parachute opening and measured the drag area to validate the design.

The parachute system will allow the Ares I and Ares V boosters to be recovered and then refurbished and reused for future flights. Ares I will launch the Orion vehicle, which will carry humans to the moon, while the larger Ares V will be used for the Cargo Launch Vehicle.

The boosters are scheduled to be flight tested in 2009.

Keep those tests coming!

Original News Source: NASA Press Release

True or False (Color): The Art of Extraterrestrial Photography

When you look at the amazing pictures captured by the Hubble Space Telescope, or the Mars Exploration Rovers, do you ever wonder: is that what you’d really see with your own eyes? The answer, sadly, is probably not. In some cases, such as with the Mars rovers, scientists try and calibrate the rovers to see in “true color,” but mostly, colors are chosen to yield the most science. Here’s how scientists calibrate their amazing instruments, and the difference between true and false colors.

So, to start off, let’s put this in the form of a true or false question: T or F: When we see the gorgeous, iconic images from Hubble or the stunning panoramas from the Mars rovers, do those pictures represent what human eyes would see if they observed those vistas first hand?

Answer: For the Hubble, mostly false. For the rovers, mostly true, as the rovers provide a combination of so-called “true” and “false” color images. But, it turns out, the term “true color” is a bit controversial, and many involved in the field of extraterrestrial imaging are not very fond of it.

“We actually try to avoid the term ‘true color’ because nobody really knows precisely what the ‘truth’ is on Mars,” said Jim Bell, the lead scientist for the Pancam color imaging system on the Mars Exploration Rovers (MER). In fact, Bell pointed out, on Mars, as well as Earth, color changes all the time: whether it’s cloudy or clear, the sun is high or low, or if there are variations in how much dust is in the atmosphere. “Colors change from moment to moment. It’s a dynamic thing. We try not to draw the line that hard by saying ‘this is the truth!'”

Bell likes to use the term “approximate true color” because the MER panoramic camera images are estimates of what humans would see if they were on Mars. Other colleagues, Bell said, use “natural color.”

Zolt Levay of the Space Telescope Science Institute produces images from the Hubble Space Telescope. For the prepared Hubble images, Levay prefers the term “representative color.”

“The colors in Hubble images are neither ‘true’ colors nor ‘false’ colors, but usually are representative of the physical processes underlying the subjects of the images,” he said. “They are a way to represent in a single image as much information as possible that’s available in the data.”

True color would be an attempt to reproduce visually accurate color. False color, on the other hand, is an arbitrary selection of colors to represent some characteristic in the image, such as chemical composition, velocity, or distance. Additionally, by definition, any infrared or ultraviolet image would need to be represented with “false color” since those wavelengths are invisible to humans.

The cameras on Hubble and MER do not take color pictures, however. Color images from both spacecraft are assembled from separate black & white images taken through color filters. For one image, the spacecraft have to take three pictures, usually through a red, a green, and a blue filter and then each of those photos gets downlinked to Earth. They are then combined with software into a color image. This happens automatically inside off-the-shelf color cameras that we use here on Earth. But the MER Pancams have 8 different color filters while Hubble has almost 40, ranging from ultraviolet (“bluer” than our eyes can see,) through the visible spectrum, to infrared (“redder” than what is visible to humans.) This gives the imaging teams infinitely more flexibility and sometimes, artistic license. Depending on which filters are used, the color can be closer or farther from “reality.”

Stone mountain rock outcrop in true and false colour. Image credit: NASA/JPL
Stone mountain rock outcrop in true and false colour. Image credit: NASA/JPL

The same rock imaged in true and false color by Opportunity.

In the case of the Hubble, Levay explained, the images are further adjusted to boost contrast and tweak colors and brightness to emphasize certain features of the image or to make a more pleasing picture.

But when the MER Pancam team wants to produce an image that shows what a human standing on Mars would see, how do they get the right colors? The rovers both have a tool on board known as the MarsDial which has been used as an educational project about sundials. “But its real job is a calibration target,” said Bell. “It has grayscale rings on it with color chips in the corners. We measured them very accurately and took pictures of them before launch and so we know what the colors and different shades of grey are.”

One of the first pictures taken by the rovers was of the MarsDial. “We take a picture of the MarsDial and calibrate it and process it through our software,” said Bell. “If it comes out looking like we know it should, then we have great confidence in our ability to point the camera somewhere else, take a picture, do the same process and that those colors will be right, too.”

Hubble can also produce color-calibrated images. Its “UniverseDial” would be standard stars and lamps within the cameras whose brightness and color are known very accurately. However, Hubble’s mission is not to produce images that faithfully reproduce colors. “For one thing that is somewhat meaningless in the case of most of the images,” said Levay, “since we generally couldn’t see these objects anyway because they are so faint, and our eyes react differently to colors of very faint light.” But the most important goal of Hubble is produce images that convey as much scientific information as possible.

The rover Pancams do this as well. “It turns out there is a whole variety of iron-bearing minerals that have different color response at infrared wavelengths that the camera is sensitive to,” said Bell, “so we can make very garish, kind of Andy Warhol-like false color pictures.” Bell added that these images serve double duty in that they provide scientific information, plus the public really enjoys the images.

And so, in both Hubble and MER, color is used as a tool, to either enhance an object’s detail or to visualize what otherwise could not be seen by the human eye. Without false color, our eyes would never see (and we would never know) what ionized gases make up a nebula, for example, or what iron-bearing minerals lie on the surface of Mars.

As for “true color,” there’s a large academic and scholarly community that studies color in areas such as the paint industry that sometimes gets upset when the term “true color” is used by the astronomical imaging group, Bell explained.

“They have a well-established framework for what is true color, and how they quantify color,” he said. “But we’re not really working within that framework at that level. So we try to steer away from using the term ‘true color’.”

Levay noted that no color reproduction can be 100% accurate because of differences in technology between film and digital photography, printing techniques, or even different settings on a computer screen. Additionally, there are variations in how different people perceive color.

“What we’re doing on Mars is really just an estimate,” Bell said, “it’s our best guess using our knowledge of the cameras with the calibration target. But whether it is absolutely 100% true, I think it’s going to take people going there to find that out.”

For more information see http://hubblesite.org/ or check out Jim Bell’s 2006 book “Postcards From Mars.”

A Submarine for Europa

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Many planetary scientists believe that Jupiter’s moon Europa is our solar system’s best contender to share Earth’s distinction of harboring life. Evidence gathered by the Voyager and Galileo spacecrafts suggests Europa contains a deep, possibly warm ocean of salty water under an outer shell of fissured ice. In a paper published in the July 2007 Journal of Aerospace Engineering a British mechanical engineer proposes sending a submarine to explore Europa’s oceans.

Carl T. F. Ross, a professor at the University of Portsmouth in England offers an abstract design of an underwater craft built of a metal matrix composite. He also provides suggestions for suitable power supplies, communication techniques and propulsion systems for such a vessel in his paper, “Conceptual Design of a Submarine to Explore Europa’s Oceans.”

Ross’s paper weighs the options for constructing a submarine capable of withstanding the undoubtedly high pressure within Europa’s deep oceans. Scientists believe that this moon’s oceans could be up to 100 kilometers deep, more than ten times deeper than Earth’s oceans. Ross proposes a 3 meter long cylindrical sub with an internal diameter of 1 meter. He believes that steel or titanium, while strong enough to withstand the hydrostatic pressure, would be unsuitable as the vessel would have no reserve buoyancy. Therefore, the sub would sink like a rock to the bottom of the ocean. A metal matrix or ceramic composite would offer the best combination of strength and buoyancy.

Ross favors a fuel cell for power, which will be needed for propulsion, communications and scientific equipment, but notes that technological advances in the ensuing years may provide better sources for power.

Ross concedes that a submarine mission to Europa won’t occur for at least 15-20 years. Planetary scientist William B. McKinnon agrees.
Artist illustration of a Europa probe. Image credit: NASA/JPL
“It is difficult enough, and expensive, to get back to Europa with an orbiter, much less imagine a landing or an ocean entry,” said McKinnon, professor of Earth and Planetary Sciences at Washington University in St. Louis, Missouri. “Sometime in the future, and after we have determined the ice shell thickness, we can begin to seriously address the engineering challenges. For now, it might be best to search for those places where the ocean has come to us. That is, sites of recent eruptions on Europa’s surface, whose compositions can be determined from orbit.”

The Jet Propulsion Laboratory is currently working on a concept called the Europa Explorer which would deliver a low orbit spacecraft to determine the presence (or absence) of a liquid water ocean under Europa’s ice surface. It would also map the distribution of compounds of interest for pre-biotic chemistry, and characterize the surface and subsurface for future exploration. “This type of mission,” says McKinnon, “would really allow us to get the hard proof we would all like that the ocean is really there, and determine the thickness of the ice shell and find thin spots if they exist.”

McKinnon added that an orbiter could find “hot spots” that indicate recent geological or even volcanic activity and obtain high-resolution images of the surface. The latter would be needed to plan any successful landing.

Slightly smaller than Earth’s moon, Europa has an exterior that is nearly craterless, meaning a relatively “young” surface. Data from the Galileo spacecraft shows evidence of near-surface melting and movements of large blocks of icy crust, similar to ice bergs or ice rafts on Earth.

While Europa’s midday surface temperatures hover around 130 K (-142 C, -225 degrees F), interior temperatures could be warm enough for liquid water to exist underneath the ice crust. This internal warmth comes from tidal heating caused by the gravitational forces of Jupiter and Jupiter’s other moons which pull Europa’s interior in different directions. Scientists believe similar tidal heating drives the volcanoes on another Jovian moon, Io. Seafloor hydrothermal vents have also been suggested as another possible energy source on Europa. On Earth, undersea volcanoes and hydrothermal vents create environments that sustain colonies of microbes. If similar systems are active on Europa, scientists reason that life might be present there too.

Among scientists there is a big push to get a mission to Europa underway. However this type of mission is competing for funding against NASA’s goal of returning to our own moon with human missions. The proposed Jupiter Icy Moon Orbiter (JIMO) a nuclear powered mission to study three of Jupiter’s moons, fell victim to cuts in science missions in NASA’s Fiscal Year 2007 Budget.

Ross has been designing and improving submarines for over 40 years, but this is the first time he’s designed a craft for use anywhere but on Earth.

“The biggest problem that I see with the robot submarine is being able to drill or melt its way through a maximum of 6 km of the ice, which is covering the surface,” said Ross. “However, the ice may be much thinner in some places. It may be that we will require a nuclear pressurized water reactor on board the robot submarine to give us the necessary power and energy to achieve this”

While Ross proposes using parachutes to bring the submarine to Europa’s surface, McKinnon points out that parachutes would not work in Europa’s almost airless atmosphere.

Ross has received very positive responses to his paper from friends and colleagues, he says, including notable British astronomer Sir Patrick Moore. Ross says his life has revolved around submarines since 1959 and he finds this new concept of a submarine on Europa to be very exciting.

McKinnon classifies the exploration of Europa as “extremely important.”

“Europa is a place is where we are pretty sure we have abundant liquid water, energy sources, and biogenic elements such as carbon, nitrogen, sulfur, phosphorus, etc,” he said. “Is there life, any kind of life, in Europa’s ocean? Questions don’t get much more profound.”

Written by Nancy Atkinson