The End of Phobos-Grunt

The doomed Russian spacecraft, Phobos-Grunt has finally come crashing back to Earth.  I didn't want to admit to myself that it was going to end this way, but now there is no denying it.  Earlier today, Phobos-Grunt re-entered Earth's atmosphere, and while some of it burned up, debris did come down in the Pacific Ocean, west of Chile.  So ends the latest Russian interplanetary mission.

Artist's conception of the Phobos-Grunt spacecraft.

Phobos-Grunt was intended to fly to the Martian moon, Phobos, and return a soil sample via a small re-entry capsule.  It would have been the first return sample from the Mars system by any nation.  However, shortly after the November launch, ground controllers in Moscow lost contact with the spacecraft.  Apparently, two planned rocket burns never occurred, and the spacecraft never left Earth orbit.  For weeks, controllers tried to re-establish contact, and except for one short communication, contact was never fully regained.  Hope remained for some weeks that the spacecraft could be salvaged, but, clearly, that never happened.

Russia (and before them, the Soviet Union) has had a long history of mission failures to the red planet.  Of the nearly 20 missions Russia has aimed at Mars, none have been complete successes, and only a handful have partially succeeded.  The Phobos-Grunt disaster is reminiscent of the Mars 96 incident, where a complex Mars orbiter and lander failed to leave Earth's orbit and burned up over the Pacific.  This latest failure, coupled with a recent spate of other space failures, has Russia's government putting the pressure on those in the space industry.  President Medvedev even went so far as to threaten prosecution of engineers and scientists who work on failed missions.  Succeed or rot in prison - a truly sound policy!

Where Russia goes from here isn't yet clear.  Russia takes space exploration seriously, and despite this latest failure, I believe they will continue with interplanetary science missions.  There is some talk of the Russians being involved with the upcoming ExoMars mission.  ExoMars is a collaboration between the ESA and NASA, and would launch an orbiter to Mars in 2016.  That orbiter could be partially outfitted with Russian instruments and be launched atop a Russian Proton rocket.  A rover would follow in 2018, but it is not yet known if Russia would help with that part of the mission.

Stuck in orbit, Phobos-Grunt as seen from Earth (Ralf Vandebergh).

Russia is an important international partner in humanity's continued exploration of space.  With luck, they will rebound from this setback, and contribute on future missions to the red planet and beyond.

Planets of the Milky Way

A new study estimates that there may be as many as 160 billion planets in our Milky Way Galaxy.  That's about 1.6 planets per star, many more than were thought to exist just a few years ago.  Most of these worlds are thought to be rocky type planets, as opposed to gas giants.  Just how many of these planets could support life, however, remains to be seen.

Interest in planets outside of our solar system, known as exoplanets, has increased dramatically in the last few years.  The amazing success of NASA's Kepler mission has fueled much of the interest.  To date, the orbiting Kepler telescope has identified nearly 3000 exoplanets.  Kepler does this by measuring the slight decreases in the amount of light a star appears to emit when a planet passes between the star and the telescope.  This is called the 'transit method' of exoplanet detection.  After a candidate exoplanet is identified this way, scientists employ ground based telescopes to back up Kepler's findings.  It is only after this that an exoplanet can be confirmed to exist.  Around 700 of Kepler's candidate exoplanets have been confirmed, and it is estimated that up to 80% of all candidates will indeed turn out to be exoplanets once further observations are carried out.

Artist's depiction of the Kepler telescope (NASA).

After Kepler identifies a candidate planet, observing that world from ground based telescopes can be done in one of a few ways.  Scientists can measure small wobbles in a star's movement caused by the gravitational pull of planets orbiting the star.  This is called the 'radial velocity' method.  Both this and the transit method are biased toward large planets that are close to their parent stars, however.  Another method that doesn't have the same bias is called 'gravitational microlensing.'  This is where a star is observed just as a closer body, such as another star, passes in front of it.  The gravity of the closer body bends and magnifies the light of the distant star, similar to a lens.  This can help resolve the relatively tiny exoplanets that may be orbiting the star.

The big question now becomes: Are these worlds habitable?  The Kepler telescope, by itself, cannot tell us this.  However, we can infer several things from Kepler's findings.  For life, as we know it, to exist, a planet must harbor liquid water.   For that to happen, a planet must be in its star's 'habitable zone'; a distance, particular to each star, where it is neither so cold that water freezes, nor so hot that water boils away.  Earth, for example, is right in our Sun's habitable zone.  Venus, with its 480 degree Celsius surface temperature and runaway greenhouse effect, is just a little too close to the Sun to be in the habitable zone.  Kepler has already identified exoplanets that are in their habitable zones, and is sure to observe more in the coming years.  It will be up to other telescopes, like the as yet to be launched James Webb Space Telescope (JWST), to probe deeper into these potentially life harboring exoplanets.  JWST will have the ability to measure the atmospheres of exoplanets, and depending on the composition, that could reveal whether or not life exists on those planets in any great quantity.

Artist's depiction of the James Webb Space Telescope (NASA).

The Kepler telescope is confirming what scientists have only been able to speculate up to now; that our galaxy is filled with stars that have planets orbiting them, just like our own solar system.  The wealth of knowledge Kepler is bringing to humanity is astounding.  Hopefully, these discoveries will drive home the point that space based astronomy is an important and vital resource in unlocking the mysteries of our universe.

China's Space Plans

Last week, the Chinese government released a 17 page white paper document entitled, "China's Space Activities in 2011."  The paper is a brief summing up of the last five years in Chinese space activities, and a preview of what to expect in the next five year space program.  While the paper isn't mind blowing in its scope or material, it does touch on some interesting points.

The accomplishments of the Chinese space program have been impressive in the last five years, and the paper focuses on the most noteworthy achievements.  Since 2006, the Long March series of rockets, China's workhorse, has had 67 successful launches, making it one of the world's most reliable launch systems.  In 2007 and 2010, China launched Chang'e-1 and Chang'e-2, respectively, which marked the nation's first serious foray into deep space exploration.  Both spacecraft successfully orbited, mapped, and studied the Moon. In 2008, China successfully launched three men aboard Shenzhou-7, a mission that saw the country's first spacewalk.  And, most recently, China launched its first space lab, Tiangong-1, and successfully remotely docked a Shenzhou spacecraft with the orbiting lab.  The paper also mentions a few scientific accomplishments, like experiments in physics and materials sciences.

Chinese astronaut, Zhai Zhigang, waves to the camera during his 2007 spacewalk (BBC).

The paper goes on to lay out a general plan for China's space program for the next five years.  A continuation of the space lab program, in preparation for a full-fledged space station is highlighted.  This next year will see another unmanned docking with Tiangong-1, as well as one manned mission to the lab.  The Chinese lunar program will move forward as well, with a plan to do a soft landing, followed by a lunar rover, and culminating in a soil return mission.  China will also develop several new rockets in its Long March series, including a "heavy lift" variant which proposes to launch 25 tons into low Earth orbit.

Possible configurations of the proposed Long March 5 family of rockets (Jirka Dlouhy).

One of the surprising things about the document is how much emphasis is put on international cooperation.  Every international space agreement China has entered into is detailed, from commercial deals with the developing world, to multi-national science missions with Europe, to Russia's cooperation with China on their manned program.  This could be a sign that China is opening up more, and by highlighting the work they have already conducted with other nations, they hope to cozy up to bigger space partners (maybe the US?).

Not surprisingly, there are some inconsistencies with what the Chinese government says, and what it does.  The paper highlights China's efforts to mitigate and track space debris.  However, in 2007 the Chinese tested an anti-satellite weapon, destroying one of their own aging weather satellites.  This incident created over 2,300 pieces of trackable space debris.  While this stunt may have demonstrated China's satellite killing ability to the world, it created more space debris than any other single event in history.  Debris from this incident has already threatened the ISS once, and will continue to be a problem for all space faring nations decades to come.

Propaganda aside, China is indeed pushing forward in all aspects of their space program, and this latest document is an interesting glimpse of where China is headed in space.  Let's hope they keep to their commitment of greater international cooperation, an increase in space science, and a reduction in dangerous space debris.

Read the full text of the white paper, here.

Organics on Pluto

Pluto may have been downgraded to 'dwarf planet' status, but there are still big discoveries to be made on the icy world.  A recent study using the Hubble Space Telescope has detected possible evidence of complex organic molecules on Pluto's surface.  Pluto is known to harbor ices of methane and nitrogen, and when high energy cosmic rays interact with these ices, organics can form.  And while it isn't likely that Pluto has any Little Green Men, organic molecules are the building blocks for life as we know it.  It's also these organics that may give the Plutonian surface its ruddy color.

Little is known about the surface of distant Pluto (NOAA).

Pluto is a member of the Kuiper Belt, a ring of frigid asteroids and dwarf planets that extends from just beyond the orbit of Neptune, at 30 AU, out to about 50 AU (1 Astronomical Unit, AU, is equal to the distance from the Earth to the Sun, or about 150 million km).  There are more than 70,000 documented Kuiper Belt objects (KBOs), and several of the larger objects seem to share Pluto's reddish surface, indicating that organics may be prevalent in the distant reaches of the solar system.

Observations by the Hubble Space Telescope aren't the only way scientists are keeping tabs on Pluto and other KBOs.  NASA's New Horizons spacecraft is set to flyby Pluto in 2015.  Launched in 2006, New Horizons left Earth with the fastest ever launch speed of a man made object, at over 58,000 km/h.  It will be the first spacecraft to visit Pluto, and its closest approach will put it just 12,500 km above Pluto's surface.  New Horizons will then continue on its journey farther into the Kuiper Belt.

A thorough investigation of the Kuiper Belt is necessary to fully understand how our solar system formed.  Identifying locations of organic molecules, and studying how those molecules came to be, will also help in explaining how life arose on our own planet. It may also give clues as to where to look for life on other worlds or in other star systems.  With luck, further Hubble observations and the New Horizons spacecraft will reveal more about mysterious Pluto.

Europa!

NASA scientists recently announced they are planning a mission to Jupiter's icy moon, Europa, to find out if the distant moon is capable of supporting life.  While the mission is only in the concept stage, and is years away from realization, it shows that NASA is seriously thinking beyond Mars for the potential of life in the solar system.

Jupiter's icy moon, Europa, as seen from the Voyager spacecraft (NASA).

The proposed mission would launch two landers in 2020, and each would be laden with 36 kg of scientific equipment.  Included would be seismometers to measure any seismic activity on the moon, as well as spectrometers to search for organic molecules and the building blocks of life.  It has been speculated that Europa might harbor life, as the moon is covered in a thick crust of ice, and some miles down may in fact have a giant ocean of liquid water.  Just last month scientists discovered there may even be shallow lakes of water right beneath the surface.

Any mission to the Europan surface would have to be a relatively quick one.  Jupiter constantly bombards the moon with massive amounts of radiation.  Without the aid of radiation shielding, a lander couldn't be guaranteed to last more than seven days on the surface of Europa, and mission scientists aren't interested in sacrificing scientific equipment for heavy radiation shielding.  Still, seven days could provide a bounty of information on the mysterious world.

Artist's conception of a lander approaching the Europan surface (futureplanets.blogspot.com)

With a potential price tag of $800 million, this proposed Europa mission would likely cost more than NASA's recent, inexpensive, New Frontiers missions, which usually run around $400 million.  However, it would likely be less expensive than a so-called 'flagship' mission, which can run into the many billions of dollars.  There had been some talk of a potential flagship Europa orbiter mission, in which NASA would have teamed up with the European Space Agency for two Jupiter system orbiters.  However, recent budget constraints have most likely killed the American portion of that mission (the ESA may continue the project without NASA support).

A mission to explore the habitability of the far flung moons of our solar system is inevitable.  Europa and Ganymede both contain large amounts of water, and Jupiter's gravitational pull may create enough friction to keep some of that water in a liquid state.  Saturn's moon Titan, which was visited by the Huygens probe back in 2005 as part of the Cassini mission, is also a prime candidate for life.  Titan is covered in lakes of hydrocarbons, and indeed has an entire climate system based on liquid methane and ethane in which life forms might flourish.  I do hope that NASA makes visiting these worlds a priority, as unlocking their secrets will undoubtedly lead to a greater understanding of how our solar system formed, and possibly reveal whether or not life ever evolved on a planet other than our own.

Phobos-Grunt Update - Promising News!

After more than two weeks stuck in Earth orbit, Russian flight engineers have finally made contact with the Phobos-Grunt spacecraft.  In a last ditch effort to save the 165 million dollar mission, the Russian space agency, Roskosmos, elicited the help of the European Space Agency and attempted to contact Phobos-Grunt using ground station antennas in Perth, Australia.  Miraculously, contact with the ill-fated spacecraft was established.  After several more passes over Perth, telemetry data was downloaded, and Russian engineers began deciphering the coded data.  Why, exactly, contact couldn't be made up until now isn't yet known, however it appears that the solar arrays of the spacecraft were in an optimal position while it was over Perth, and the extra energy generated allowed for Phobos-Grunt to communicate with Earth.  It still remains unclear what exactly caused the failure of the orbital engine burns, but further analysis of the data and continued contact with the spacecraft will most likely allow engineers to discover the problem.

Phobos-Grunt mission poster (Roskosmos).

Now the question becomes - if Phobos-Grunt can be saved, what to do with it?  The window to send the spacecraft to Mars appears to now be closed, although some debate on this matter remains.  If, indeed, it is too late to try for Mars, the mission may still be salvaged.  One option is to keep the spacecraft in Earth orbit for another two years, until the launch window for Mars again opens, and then send it on its way.  Although, there may not be enough fuel on board for this.  The other option is to completely change the mission objectives, and send the spacecraft to a near Earth asteroid.  The parameters of the mission would essentially be the same, as Phobos is thought to be an asteroid that was captured by Mars's gravity.  So landing on an asteroid, and launching the soil recovery capsule, wouldn't be outside the abilities of the spacecraft.  However, it would take new software and new calculations, and a completely new flight path - and that too could take some time.  Of course any of these options require that enough data can be downloaded from the spacecraft to isolate the initial problem, and then that problem must be fixed.

If Phobos-Grunt cannot be salvaged, it will burn up upon re-entry into Earth's atmosphere on or about January 15th, 2012.  Read more here.

New Moon Map

This week, scientists released the best topographical map of the Moon ever created.  The new map, which covers 98.2 percent of the Moon's surface, gives detailed topo information down to the 100 meter scale.  This is an impressive feat that could only have been accomplished with NASA's Lunar Reconnaissance Orbiter (LRO).

The new, detailed, topographic map of the moon (NASA Goddard).

LRO, launched in 2009 and costing a little over $500 million, has been a resounding success.  In addition to the camera and on board altimeter that helped create the new topographic map, LRO has a number of other high-tech devices; the Diviner Lunar Radiometer Experiment (DLRE) has created a thermal map of the Lunar surface, while the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) is helping to determine how detrimental cosmic rays might be to biological organisms on the Moon's surface.

The completion of this map comes at an opportune time.  Early next year, NASA's twin GRAIL spacecraft will arrive in lunar orbit, and create the most accurate gravity map of the Moon to date.  This combination of topographical, thermal, and gravity mapping will give scientists truly new insights into all aspects of the Moon's formation and subsequent development.

It's good to see that while NASA's manned program is shifting away from the Moon toward asteroids and Mars, a healthy robotic exploration of the Moon continues.  And it isn't just NASA that shows continued interest in the Moon.  As I've discussed before, China has distant plans to land human beings on the Moon - and while that might be a while off, they have launched two orbiters to our natural satellite, Chang'e 1 and Chang'e 2, as part of their own robotic exploration program.  India, also, launched and operated the highly successful Chandrayaan-1 spacecraft in orbit around the Moon.

There are also a number of private companies and individuals showing interest in lunar exploration.  Bigelow Aerospace wants to build inflatable habitats on the surface of the Moon to compliment their planned inflatable orbital station.  Shackleton Energy is looking into the possibility of extracting hydrogen and oxygen from the lunar surface, processing it into fuel, and building a fuel depot in lunar orbit.  And the Google Lunar X Prize, a $30 million contest to put a rover on the Moon, has some serious entries from cutting edge engineering teams from across the nation.  These are all ambitious plans, but the greater number of entities interested and involved in lunar exploration, the more the cost will come down, and the greater the chances of success of one or more of these projects.

Artist's rendition of a Bigelow Aerospace lunar base (Bigelow Aerospace).

Lunar exploration will go forward, and NASA's continued remote exploration of our closest neighbor will be absolutely vital.  My hope is that lunar programs don't lose steam with the coming robotic and manned explorations of other bodies in the solar system.