Close Encounters: Meteor lands in Russia

June 21, 2013 in NOVA by dmpastuf

An early morning surprise

On February 15th, 2013, the Russian city Chelyabinsk got the surprise of a lifetime when an asteroid hurtled down through the atmosphere, disintegrating into thousands of pieces that rained down on the ground. Amateur videos from car dashcams—intended to catch insurance frauds—instead captured a glowing fireball streaking across the sky. Reports indicate that at its peak, the object hurtling towards Earth was brighter than the sun. A great thundering sound was heard soon afterwards, and witnesses in the area said that the air of the city smelled like gunpowder.

The event garnered immediate worldwide attention and social media sites erupted at the news. Initial reactions were skeptical for the most part since meteors rarely have a significant effect on the ground, given that most fully disintegrate on their descent. After confirmation by the Russian government, however, the meteor became the hottest story of the day. Videos from Russian citizens’ dashcams of the meteor made their way to Youtube, cultivating millions of views in a matter of hours.

Meteorite contrail is seen in a frame from a video acquired with a dashboard camera, on a highway from Kostanai, Kazakhstan, to Chelyabinsk region, Russia; Image Credit: AP Photo/Nasha gazeta, www.ng.kz

Meteorite contrail is seen in a frame from a video acquired with a dashboard camera, on a highway from Kostanai, Kazakhstan, to Chelyabinsk region, Russia; Image Credit: AP Photo/Nasha gazeta, www.ng.kz

There were a number of injuries sustained by the local population, though very little resulted from the debris. Nearly 1,500 people sought medical attention in Chelyabinsk, and this number included over 300 children. Though most the injuries were minor, there were several reports of residents being hospitalized with significant injuries, though all were expected to survive.

One of the largest causes of injury was curiosity—as the meteor brightened up the sky with its fiery light, people flocked to windows to get a better look. Unfortunately, windows are one of the most dangerous places to be in the event of an external explosion, since the force will blow back the glass into the faces of the onlookers. As a result, many people were hurt by falling shattered windows and glass, resulting in cuts and bruises. The meteor also shut down the local infrastructure, closing down government buildings alongside private businesses to bring the area to a grinding halt.

There was also serious damage sustained by residential and business buildings, schools and even hospitals, leaving thousands of citizens homeless following the blast. Most of these structures were not hit directly by the debris, but instead became damaged as a result of the shock wave. To this day, only a fraction of the repairs have occurred, leaving Chelyabinsk in a lurch in the aftermath.

Though the effects of meteor were disastrous, it was fortunate that it came into contact with a relatively isolated and low-populated area. Had the meteor come near a high-density region, such as New York City or Beijing, the effects would be catastrophic due to the high rises and skyscrapers, and deaths would have been a near certainty.

So, what kind of meteor was it, and why did it cause so much damage?

According to researchers, the Chelyabinsk meteor was the most powerful in over a 100 years, dating back to the Tunguska meteor from 1908. Calculations of the meteor range between research centers, but the average shows that the meteor was approximately 50 feet wide and weighed around 7,000 tons, or the weight of two large vehicles when it first broke through the earth’s atmosphere.

The majority of the meteor’s damage did not come from impact, as the pieces that fell were relatively small. Rather, the culprit was a series of shockwaves resulting from several explosions that occurred as the asteroid broke up in the atmosphere.

Zinc Factory in the Chelyabinsk Region of Russia post-meteor. Image Credit: Zhenya Khazhei via RIA Novosti at en.ria.ru

Zinc Factory in the Chelyabinsk Region of Russia post-meteor. Image Credit: Zhenya Khazhei via RIA Novosti at en.ria.ru

According to the Russian Geographical Society, the Chelyabinsk meteor created three blasts of varying power. The first explosion occurred around 60km above sea level and was the most powerful. The explosion was preceded by a bright flash, which lasted about five seconds, and estimates of the explosive power average around 500 kilotons. For comparison, the nuclear blast that devastated Hiroshima during World War II was approximately 13 kilotons, making the power of the blast commensurate with that of a small fusion bomb.

The asteroid itself was likely a stray originating from the asteroid belt, the famous region containing hundreds of thousands of asteroids located between Mars and Jupiter. An analysis of the meteor’s contents revealed that it was a rocky meteor composed of a relatively low iron content, and “was made of material that had been partially melted and recrystallized from the dust and gas cloud of the early solar nebulas”, according to nature.com.

Part of the reason the asteroid exploded in the first place was likely due to its fragile body. Instead of being a dense, solid, study object, the asteroid contained many internal cracks that allowed it to explode into thousands of fragments under the intense pressure of hurtling through earth’s atmosphere. Researchers have theorized that the asteroid may have come into close contact with other celestial bodies, causing damage inside of the object before it collided with Earth.

Most research centers on the lookout for asteroids can only detect meteors that are over 100 meters in size—this gives telescopes the ability to examine large enough reflections of light to determine the presence of a foreign object. The Chelyabinsk meteor, on the other hand, was only around 15 meters and dark in color, making it virtually impossible to identify ahead of time, and so it was able to fly into the atmosphere under the radar.

An ice hole in Lake Chabarkul, Chelyabinsk Region, where pieces of a meteorite could allegedly fall December 15. (RIA Novosti)

An ice hole in Lake Chabarkul, Chelyabinsk Region, where pieces of a meteorite could allegedly fall December 15. (RIA Novosti)

Could we have seen it coming?

The damage of the Chelyabinsk meteor has hit a nerve, however, as it exposed the holes in current technology and renewed calls for an increased priority given to detecting foreign, celestial objects. At issue is funding, however, and at a NASA funding hearing following the event scientists could not reassure members of Congress that they could stop a potentially devastating asteroid without an increased budget to pay for the necessary technological advances. Their testimony prompted Rep. Lamar Smith to say, “We need to find ways to fund NASA’s projects.”

And the funding is needed. Due to its speed combined with the meteor’s size, current centers—if they could detect the asteroid at all—would only have a day or two at the most to provide a warning, which may not be enough time to properly evacuate regions like Siberia, and definitely not enough time for a large metropolitan area such as London.

The Mars 2020 Rover: A Chance for a Sample Return Mission

June 21, 2013 in NOVA by dmpastuf

On December 4th 2012, it was announced that NASA intends to launch another rover to Mars in 2020. The successful landing and science conducted by the Mars Science Laboratory (MSL) Curiosity rover has renewed the confidence of the agency to replicate its success. Utilizing the same basic design as MSL and over $200 million worth of flight ready hardware leftover from development, NASA hopes this will reduce mission costs by almost a billion dollars.

What the 2020 rover will be designed to investigate has yet to be announced. Many speculate, and hope, that this mission will be a chance to fulfil the highest priority of the 2010 Planetary Science Decadal Survey.  Every ten years, the National Research Council prepares a document listing the highest priority goals listed by scientists from various fields, and in the case of planetary science, the report was published in 2010. The Decadal Survey listed a Mars “sample return” mission as the most sought after goal of the planetary science community.

President Obama at the Kennedy Space Center in April 2010. His speech involved predicting a U.S. crewed orbital Mars mission by the mid-2030s

Few mission concepts have endured like the tantalizing prospect of collecting a sample from the surface of Mars and returning it to Earth for study.  Numerous studies have been performed, landing vehicles designed, and funding sought.  The technical challenges would be immense.   Prohibitive costs have always been cited as the greatest challenge, however.

The task of retrieving a Martian rock sample will be difficult and more than a little complicated.  During the Apollo missions, astronauts were able to simply collect lunar regolith samples in a bag and return to Earth for study in their command module capsule.  Unfortunately, there won’t be any astronauts on Mars to attempt a similar method of sample collection for years to come.  This means NASA and its partners will need to develop a robotic vehicle to operate in the place of human astronauts.

Presently, a Mars sample return mission would require a series of vehicles in order to complete this “holy-grail” of planetary science goals. A three-tiered mission architecture is envisioned; one vehicle to collect and cache a sample, a second to launch and fly to Martian orbit, and a third to collect it from the orbiter and return to Earth where it would re-enter the atmosphere and land so the sample could be extracted. The 2020 rover could, if chosen to do so, could become the first leg of this journey.

 

This is not the first time a sample return mission has been proposed.  For as long as the world’s space agencies have launched interplanetary probes, studies have been done to determine the feasibility of collecting a sample for return and examination on Earth.  While technologically difficult, it is not without precedence – the Japanese Hayabusa probe successfully collected a microscopic surface sample of the asteroid Itokawa in 2010. The Russian space Agency Roscosmos attempted to launch a similar mission to Phobos, the larger of Mars’ two moons, but the probe was lost following a launch vehicle anomaly.

NASA recently selected the members of the Science Definition Team (SDT) from a list of hundreds of potential candidates, who together will determine the mission and goals of the 2020 rover.  With selection complete, the process of choosing instrumentation and science teams can now begin.  One can expect that a number of instruments will be designed to identify potential elements that may have sustained life, if it ever existed on Mars. Many hope that this team will decide upon sample-return as the 2020 rover’s primary mission. Both the Planetary Society and the American Astronomical Society’s Division for Planetary Sciences (DPS) have endorsed the proposal to conduct a sample return mission.

The Mars 2020 Rover will feature many borrowed parts from the Curiosity Rover currently on Mars; Image Credit: NASA

However, the 2020 rover (which has yet to acquire a name similar to rovers that preceded it) will likely be the only “flagship” mission for planetary science in the next decade.  Reductions to the planetary science budget, sequestration, and the rising costs of other NASA projects have forced planetary scientists to focus on smaller, less-expensive and shorter-term missions in order to study the moons and planets of our Solar System.  Even exploration of the red planet, which has seen an armada of probes and rover in the last decade, will see fewer mission directed toward its study.

Because of the reduced spending on planetary science missions, NASA may decide it will be more prudent to equip the 2020 rover with instrumentation for analysis on Mars, as MSL and MER currently do. The possibility that the “return” legs of the sample return mission profile might not be adequately funded (or worse, cancelled) could lead to an expensive mars rock collecting rover with no way to deliver its cargo to Earth for study. Like Curiosity, the 2020 rover might carry a range of remote sensing and contact instruments to study geology and potential astrobiology.

How likely is it that the 2020 Mars rover will be part of a greater sample return architecture? That remains to be seen.  NASA will face a number of annual budget cycles before the rover’s construction must be completed for the intended launch window.  In that time, Administrations will change, NASA leadership will change, and the agency will also be conducting the most ambitious beyond-low-Earth-orbit (BLEO) human exploration missions since the Apollo Lunar missions ended in 1972.  How much commitment the planetary science community gives to Mars sample return may depend on how well the budget supports other missions, particularly the lagging exploration of the outer planets.

At the annual Lunar and Planetary Science Conference (LPSC), held in Woodlands, Texas this year, it was noted that future efforts toward studying the gas giant planets and their multitude on moons will be diminished because of the budget for Flagship-class missions. NASA’s Science Mission Directorate (SMD) continues to support Discovery-class missions to the outer planets, but the price cap on mission costs will make such endeavors unlikely.  Is this indicative of a Mars-bias? Some scientists think so, but that would be in-line with the agency goals of eventually supporting human missions to Mars in the 2030 timeframe.

Indeed, 2 more missions were announced just prior to the announcement of the 2020 rover. Mars  Atmosphere and Volatile Evolution, or  MAVEN, an orbiter designed to study the Martian atmosphere will launch next year- and InSight (which stands for Interior exploration using Seismic Investigations, Geodesy, and Heat Transport) , a lander based on the successful 2008 Phoenix mission, which will use a drill device to probe the planet’s crust, will launch in 2016.  Taking advantage of the 2018 launch window will be the joint European Space Agency (ESA) and Russian space agency (Roscosmos) ExoMars rover mission.  The ExoMars mission will incorporate an ambitious plan to utilize an orbiter and a rover for a planned multi-year study.  These missions, as well as the NASA rovers Opportunity and Curiosity, are adding to our knowledge of Mars over the coming decade.

While Mars exploration continues with the rovers presently on the surface and the orbiters overhead, the question remains as to whether NASA’s 2020 rover will play any role in a sample return mission. The planetary science community looks forward to the decisions made by the SDT. In either case, the coming decade will be an interesting one to watch when it comes to the 4th planet in our solar System.

Casey Stedman (@Stedman_casey) is affiliated with ERAU-Worldwide Campus