Archive for the ‘Asteroids’ Category

Past, Present, and Future – Current Events in Space

Monday, December 8th, 2014

2014 was a big year for space science and exploration, and 2015 is poised to be just as exciting. Lets take a look back at some of the year’s biggest stories from NASA, ESA, other government agencies, and the private space industry, and look forward to what is coming in 2015.

Rosetta’s orbit of 67P

Rosetta and Philae

Arguably the most widely covered space mission of the year was the European Space Agency’s Rosetta mission to Comet 67P/Churyumov-Gerasimenko. The Rosetta spacecraft was launched in 2004 and arrived at the comet on August 6, 2014. Rosetta used four different slingshots around both Earth and Mars to build enough speed to catch up to 67P, which is traveling at about 84,000mph. In total, the spacecraft has traveled more than four billion miles in it’s ten year journey.

Philae Lander

On November 12, 2014, the lander portion of the Rosetta mission, known as Philae, landed on the surface of Comet 67P. Because the comet is relatively small (only about 2.5 miles in diameter), the gravity is not strong enough to hold objects to it. Philae was designed to use both harpoons in its feet, as well as a top-down thruster to hold it to the surface. Unfortunately, both devices failed, and Philae went skipping across the surface of the comet. This resulted in a landing location with little sunlight, rendering the craft unable to continue operating due to power shortages after about three days. 

Despite the landing troubles of Philae, the mission has been considered a monumental success, and significant scientific research is being accomplished because of the information Rosetta and Philae have gathered. Rosetta will continue to orbit Comet 67P until December 2015. During this time, the comet will make a closer approach to the Sun, which has the chance to increase the power received by Philae, to the point where it could be awoken again.

 

Orion Capsule and Delta IV Second Stage

Orion Exploration Flight Test

Another heavily covered space event occurred just a few days ago. The Orion spacecraft, NASA’s first spacecraft since Apollo designed to take humans beyond low Earth Orbit, was launched on it’s very first flight on December 5th. Orion was elevated to a distance of 3,600 miles above the Earth’s surface, and returned through the atmosphere at 20,000 miles an hour. This velocity was necessary to test Orion’s heat shield, which will protect astronauts on their return trip from deep space.

Orion was launched atop a United Launch Alliance Delta IV rocket. Orion is ultimately destined to ride atop the Space Launch System (SLS), which will be tested for the first time in 2018. Orion’s ultimate goal is to transport humans to and from Mars, which NASA has projected for a mid 2030 timeframe.

Boeing’s CST-100 (left) and SpaceX’s Dragon

 

Commercial Crew Transportation Program

In September of 2014 NASA announced partnerships with two companies, SpaceX and Boeing, for manned transportation to the International Space Station. Since the end of the Shuttle program in 2011, NASA has been contracting rides to the ISS for its astronauts on the Russian Soyuz spacecraft. in 2017, the United States will return to the business of human space travel with the Boeing CST-100 and SpaceX Dragon spacecraft.

 

New Horizons Spacecraft

New Horizons

NASA’s New Horizons mission is currently en route to Pluto. Launched in 2006, New Horizons plans on being the first spacecraft to visit the solar system’s former ninth planet. This will give us the best pictures ever of Pluto and it’s moon, Charon. New Horizons just woke up from it’s most recent slumber, and plans on arriving at Pluto On July 14, 2015. Because of the velocity needed to get to Pluto’s orbit, New Horizons will not stop at Pluto, but instead perform a flyby on it’s way into the Kuiper belt, to study other Trans-Neptunian objects.

 

Dawn Spacecraft

Dawn

Dawn is an unmanned spacecraft currently approaching Ceres, the only dwarf planet in the inner solar system, and just over one third the diameter of our Moon. Dawn was launched in September 2007, and is set to arrive in orbit around Ceres in April 2015. In 2011 Dawn also visited Vesta, a large asteroid in the asteroid belt, and will become the first spacecraft to orbit two different celestial bodies. Dawn uses a unique and experimental Ion Thruster propulsion system to allow it to enter and exit orbits efficiently. It is one of the first missions to utilize this technology, which accelerates charged particles with electromagnetic fields.

Deflecting Disaster – Can we Prevent Armageddon via Asteroid?

Sunday, August 31st, 2014

The threat of a large asteroid collision with the earth is not just the basis of a good movie plot, but an actual concern that scientists are monitoring daily.

Scientists use the Torino Scale to determine the level of concern for discovered Near Earth Asteroids (NEOs). As discussed in a previous article, the Torino scale ranks NEOs on a zero to ten scale based on both the probability of impact, as well as the potential devastation due to size. An asteroid greater than about one mile in diameter would impact the earth with more than one million times the energy of the nuclear bomb dropped on Hiroshima. This would not only wipe out anything within a 200 mile radius of the impact point, but due to dust and debris thrown into the atmosphere, would cause worldwide devastation.

Avoidance Techniques

There are essentially two frames of thought when considering asteroid deflection – direct and indirect intervention. Direct intervention send some sort of explosive device directly at the asteroid to obliterate it into fragments small enough to burn up in Earth’s atmosphere. Indirect intervention exploits the fact that with adequate warning, an asteroid’s trajectory need only be modified by a fraction of a degree over time to miss an Earth impact. Thus, slow and consistent techniques of trajectory modification are employed.

asteroidDirect Intervention

This is pretty straight forward. We would send a rocket directly at the asteroid to impact its surface, modifying the trajectory or reducing it to acceptably small fragments. This could either be a high-mass spacecraft, or a nuclear weapon detonating upon collision. This is currently the best option for asteroid deflection, as it requires the least amount of lead time, and is the simplest (and therefore cheapest) spacecraft necessary.

In 2005 the Deep Impact spacecraft successfully collided with the nucleus of comet Tempel 1. This was the first time a spacecraft has impacted a comet or asteroid. The comet’s trajectory was modified by about four inches. Knowledge gained from this impact is vital for understanding the effects of spacecraft collisions with celestial bodies.

Indirect Intervention

Example Gravity Tractor spacecraft

As opposed to a quick solution such as a nuclear strike, the indirect redirection of an asteroid has the likelihood of a higher success rate due to its slow trajectory modification approach. In the gravity tractor technique, a relatively large spacecraft would hover next to an asteroid, using its mass to gravitationally pull the asteroid towards it. With adequate lead time, a trajectory modification of a fraction of a degree is all that is necessary to deter an impact event. This also is an effective strategy if the asteroid is actually made up of a collection of asteroids, known as a “rubble pile”, which direct intervention is ineffective against.

In the Event of an Impact Detection

Tomorrow if astronomers discovered an asteroid on a collision course with Earth, would we have the capability of deflecting it? The answer depends on both the size of the asteroid and the time until impact.

Currently there is no known spacecraft equipped to handle an immediate launch to an asteroid. Thus, in the event of impact detection, developing this rocket or retrofitting an existing rocket with asteroid deflection technology would take significant time.

Dr. Edward Lu, physicist, former astronaut, and head of the private NEO detecting program B612 Foundation, made the following comments when asked in a senate hearing about the duration of time needed to develop and execute an impact asteroid: “I think with 10 years you can do this in a controlled manner with backups and so on. Certainly, with 20 years you could do that. It gets much more difficult the closer in it is, and that is, again, the importance of getting early warning, because the closer it is to you, the more you need to deflect it by to get it to miss… Five years or less, it is really hard unless you have thought the problem through and design things, maybe have components built, maybe have a full system”

If something like a city killing asteroid is discovered to impact the Earth in the next five years, the most likely course of action would be a repeated bombardment of direct impacts. While a single spacecraft may not transfer enough energy to push the asteroid off course, a dozen or more may have the necessary combined effect to avert disaster.

The Future of Human Spaceflight – Part 2: Mars

Sunday, August 24th, 2014

NASA’s SLS rocket carrying the Orion spacecraft

In the previous article we discussed the transitioning burden of human spaceflight to low Earth orbit (LEO) from NASA’s dependency on the Russians to private industry such as SpaceX and Boeing. In doing so, NASA set its sights on manned deep space missions, that will take place over the next few decades.

In the 1960s NASA pioneered human spaceflight with a series of manned spaceflight programs known as Mercury, Gemini and Apollo. Each program was divided into a series of missions building upon each other as stepping stones to reach the ultimate goal of putting humans on the moon. Apollo 11 was the first to achieve this goal, occurring in July 1969. On December 14, 1972 Apollo 17 left the moon, marking the last time humans traveled beyond LEO.

The Path to Mars

In the same way as the manned spaceflight programs from the 1960s and 1970s, NASA has ostensibly laid out a series of potential mission objectives that ultimately culminate in landing humans on Mars in the 2030s. Though these missions are far from guaranteed (and subject to budget cuts), the Space Launch System (SLS) and Orion spacecraft are taking these milestone missions into account during their design phases.

Canadian Astronaut Chris Hadfield monitoring a plant experiment on the International Space Station

The International Space Station

The first step in our journey to Mars is underway right now. Astronauts on the ISS are performing experiments to better our understanding of long term space exposure to the human body. In a document issued by NASA on May 29th, 2014 entitled “Pioneering Space: NASA’s Next Steps on the Path to Mars”, NASA indicated their research specifically targets “decreased gravity affecting bone, muscle, cardiovascular and sensorimotor systems, nutrition, behavior/performance, immunology and the ability to provide remote medical care via telemedic” It also provides us with a test bed for developing better technologies in areas such as spacecraft docking, life support, and extravehicular activity.

The Moon

While NASA may not be landing humans on the Moon anymore, it still provides an excellent place to test long duration, self sustaining systems in a low-risk environment. The first manned missions of the Orion and SLS, slated for 2021-2022, will send humans into an extended lunar orbit to prove the capabilities and habitability of the spacecraft.

Lunar orbit also is valuable for future missions in that the Moon’s gravity is one-sixth of Earth’s. Conceivably, a long duration mission to Mars could be staged and launched from lunar orbit, reducing the fuel requirements to reach cruising velocity to Mars. In this scenario, a manned rocket could be refueled in lunar orbit, increasing the potential payload launched from Earth and decreasing the cost of the mission.

Asteroid Redirect Mission (ARM)

Artist rendition of a potential asteroid redirect mission spacecraft

In addition to human spaceflight, NASA also has projects involving deep space missions to near Earth asteroids (NEAs). To leverage this technology, NASA has decided to attempt a NEA capture and transfer into lunar orbit using robotic spacecraft powered by a solar electric propulsion (SEP) rocket in 2019. Once placed in lunar orbit, astronauts will take Orion to the asteroid, and attempt Extra Vehicular Activity (EVA). This will be the first time a human has set foot on an asteroid, slated for 2025.

The purpose of this mission is complex. From a scientific standpoint, asteroids are extremely old remnants of the early solar system, thus scientists want a closer look at their chemical makeup to help us understand how the solar system was formed. In terms of technology, it will be an impressive feat to both capture and relocate an asteroid, and SEP technology can later be used to transfer cargo to Mars in anticipation of a manned mission, effectively creating a Martian space station before humans ever arrive. Additionally, it will provide an excellent test of Orion’s ability to rendezvous with robotic spacecraft, and give astronauts a chance to test EVA in a low-gravity environment.

Phobos and Deimos

Before landing humans on Mars, NASA may launch a mission to one of Mars’s moons, Phobos or Deimos. Though scientists currently believe they are captured asteroids rather than pieces of Mars broken off, they could provide access to Martian material accrued from millions of years of meteor strikes to the martian surface. The also provide a test environment for landing men in a deep space environment, as Phobos’s gravity is 650 times weaker than Mars’s.

Artist rendition of the first humans on Mars

Mars Landing

Sometime in the 2030s, NASA plans to attempt the first landing of humans on another planet. This will be a culmination of the aforementioned programs, as well as countless hours of development and testing by NASA, partner space programs, and commercial space companies. As of now a mission to Mars will take a minimum 550 days, with more than 95 percent of that time spent in deep space between Earth and Mars. A Martian lander has yet to be developed, but will come to fruition as scientists and engineers learn more about Mars, and human sustainability in deep space.

The Biggest in the Universe…

Saturday, November 23rd, 2013

Welcome to the first installment of the Vikings Astronomy Superlative Series. In the coming articles we will evaluate the most mind-blowing facts astronomy has to offer.

Galaxy

The largest galaxy observed in the universe is the ESO 146-IG 005 Galaxy. This galaxy was initially measured by the Gemini South Telescope in 2010, and exists approximately 1.4billion light years from Earth.  The ESO 146-IG 005 galaxy is about 30 trillion solar masses, which is 50 times larger than the Milky Way. It has been increasing its mass since the early stages of the universe by merging with smaller galaxies in its local group.

The most massive spiral galaxy is known as ISOHDFS 27. It is much further from Earth than ESO 146-IG 005, at approximately six billion light years. It is only about four times as large as the Milky Way.

Star

Our sun has a mass of about two nonillion kilograms, or 2,000,000,000,000,000,000,000,000,000,000kg. That’s about 1,300,000 times more massive than the earth. However the sun pales in comparison to the largest stars of our known universe.

NML Cygni is currently the largest known star, a red hypergiant roughly 25-40 times more massive than our sun. Its radius is even more impressive, approximately 1,650 times that of the sun. It is a part of the Milky Way, at about 5,300 light years from earth.

Ceres

Asteroid

The largest asteroid in the solar system is actually considered a dwarf planet. Ceres is 950km (590 mi) in diameter, and has a mass of 9.46×1020 kg. Ceres exists in the asteroid belt, which is an area of the solar system between mars and Jupiter. Ceres accounts for about one third of the entire mass of the asteroid belt. It was discovered on January 1st, 1801 by Guiseppe Piazzi, and was originally classified as a planet. The Dawn spacecraft is currently on its way to Ceres, and should arrive in 2015 to perform observations which will help scientists understand the early solar system. This will be the first time we’ve gotten an up close look at Ceres.

Exoplanet

As we learned in a recent article, there are hundreds of known planets outside of our solar system orbiting nearby stars. Because of the techniques used to find these planets, it is usually much easier to find large ones rather than small ones. Currently the largest confirmed exoplanet is CD-35 2722 b, which is approximately 31 times the size of Jupiter. Jupiter, for reference, has a mass of about 318 Earths. It was discovered in 2011.

Spacecraft

International Space Station

The largest manmade object that exists in space is the International Space Station (ISS). The ISS is a joint effort between multiple space agencies, and has been in space since 1998. It currently has a mass of about 990,000 lbs (450,000 kg). The space station has been slowly adding components since its launch, and may operate until 2028.

Saturn V Rocket During Launch

The largest (and most powerful) rocket ever to launch into space is the Saturn V rocket used by NASA during the late 60’s and early 70’s. It stood 363 feet tall, with a diameter of 33 feet, and weighed in at 6.2 million pounds. It was used during NASA’s Apollo program to launch spacecraft into Low Earth Orbit (LEO) as well as to the moon.