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CURIOSITY TOUCHDOWN 10:31PM PDT (12:31AM CDT) TONIGHT!!! August 5, 2012

Posted by jcconwell in Astronomy, planets, Space Craft.
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TONIGHT the largest rover ever to land on a planet will enter Mar’s astmosphere! Curiosity is over 5 times bigger than the previous Mar’s rover. To get the details of what is refereed to the “7 minutes of terror” , which is what the scientists call the time it takes to enter the Martian atmosphere and land, click on the NASA video below. Since Mars is 154,000,000 miles away it takes a light or radio signal 14 minutes to reach Earth. So the landing is totally controlled by the on-board computer reading the  sensors, and then adjusting the course. For the scientists waiting on Earth who have spent a good part of a decade on this mission, it will be closer to 7+14=21 minutes of terror, before they know if it is a success or a failure.

There will be a GOOGLE+ hangout event sponsored by Universe Today at http://goo.gl/a5t4O

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Commercial Space Flight July 23, 2012

Posted by stemtastic in Space Craft.
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Imagine traveling in space like you have seen on Star Trek, Star Wars, and other space adventure movies. What used to seem like a far-fetched idea only possible in science fiction is now becoming a possibility. While we may not be able to hop in our personal spaceship and head to another planet or galaxy, commercial space flights are a reality. Private companies are now able to transport cargo into space and very soon, people will be able to take flights into space.

After 30 years of service, NASA ended the Space Shuttle program in 2011 with the final flight of Space Shuttle Atlantis. Although NASA retired the Space Shuttle program, it still needs to accomplish missions in space. The development of NASA’s Commercial Crew Development (CCD) program has been designed to create partnerships with United States industry to develop safe and efficient space vehicles to transport astronauts and cargo to the International Space Station (ISS) and other Low Earth Orbit (LEO) destinations. Companies such as Boeing, Sierra Nevada, and SpaceX are working with NASA engineers to design, test, and certify transportation systems that will provide transportation for astronauts and cargo to places like the ISS.

SpaceX recently reached a major milestone in the history of space travel. On May 31, 2012, the spacecraft Dragon became the first commercial spacecraft to complete the mission of successfully transporting cargo to the ISS. The unmanned Dragon lifted off from Cape Canaveral Air Force Station on May 22. After being docked to the ISS on May 25, it spent 6 days being unloaded and loaded with new cargo to be returned to Earth.

The Dragon spacecraft was propelled into space by the Falcon 9 launch vehicle. Falcon 9 is a two stage, liquid oxygen and rocket grade kerosene powered vehicle.  Dragon is a reusable spacecraft designed to transport both pressurized and unpressurized cargo as well as crewmembers from LEO. The only mission completed so far has been unmanned.

In 2008 SpaceX’s Falcon 9 launch vehicle and Dragon spacecraft were selected by NASA to supply the ISS through a minimum of 12 flights for a contracted $1.6 billion. Based on the successful first delivery of cargo, it appears that SpaceX is well on its way to fulfill their obligation.

Commercial space transport helps NASA in a couple of ways. First, it allows NASA to send astronauts to the ISS without needing to hitch a ride on Russian spacecraft. Once the Shuttle program was retired, NASA had no way of sending astronauts to space. SpaceX and companies like it will once again make that a possibility in the near future. Commercial space transport also frees up resources for NASA to develop its deep space exploration program including the Orion Multi-Purpose Crew Vehicle and heavy lift Space Launch System (SLS).

Another area of commercial space flight that is gaining attention is space tourism. Virgin Galactic is one company providing the opportunity for people to experience sub orbital flight. The company claims to be on track for powered flight by the end of 2012. On June 26, 2012, they successfully completed a glide flight test and rocket motor firing. For a mere $200,000, you can purchase a ticket for the experience of a lifetime.

SpaceShipTwo is Virgin Galactic’s air launched glider with a rocket motor. In space, it will use small thrusters to maneuver. Since safety is a top priority, the spacecraft will use a hybrid rocket. This type of rocket uses the advantages of two types of rocket propulsion. It has the simplicity of a solid fuel rocket and the ability to be throttled or shut down like a liquid fuel rocket.

Another major safety design involves the way the spacecraft will re-enter Earth’s atmosphere. Before descending to Earth, the tail structure can be rotated up to about 65°. This allows the pilot to easily control altitude while keeping the spacecraft parallel to the horizon. This is accomplished without complicated fly-by-wire systems. Once the spacecraft has re-entered the atmosphere, the feather lowers to its original position and it is a glider to complete the trip home. According to their website, Virgin Galactic’s Burt Rutan designed SpaceShipTwo “uses aerodynamic design and the laws of physics for a carefree and heat free re-entry followed by a glide runway landing.” For safety, the spacecraft will be transported to an altitude of 50,000 ft by its launch vehicle WhiteKnightTwo. At this altitude, the spacecraft will be above most of Earth’s atmosphere thereby reducing the amount of drag the spacecraft has to overcome. Once SpaceShipTwo has been released, it will fire a rocket and ascend at 2500 mph to 62,000 feet. At this altitude, the passengers will be able to see some of the curvature of Earth and experience five minutes of weightlessness.

It may have seemed like the United States was giving up on space exploration and opportunities but the new age of commercial space flight has turned that around. More than ever before, we have the opportunities to provide more efficient space transportation systems to further research in space labs, explore deep space, and provide thrill seekers with a once-in-a-lifetime opportunity.

References

http://www.nasa.gov/exploration/commercial/index.html

http://www.spacex.com/index.php

http://www.virgingalactic.com/

New Podcast: Apollo 11: Part 2 – The Landing July 21, 2011

Posted by jcconwell in Podcast, Space Craft.
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Title: Apollo 11: Part 2 – The Landing

Podcaster: Steve Nerlich

Organization: Cheap Astronomy

Link: www.cheapastro.com

Description: This is the second of an epic podcast trilogy, celebrating the 42nd anniversary of the first Moon landing.

Bio: Cheap Astronomy offers an educational website in peace, for all mankind – as long as it doesn’t cost too much.

Sponsor: This episode of “365 Days of Astronomy” is sponsored by the Physics Department at Eastern Illinois University: “Caring faculty guiding students through teaching and research” atwww.eiu.edu/~physics/

Yes!! We really did land on the Moon 40 years ago,Today! July 20, 2009

Posted by jcconwell in Astronomy, IYA 2009, moon, Space Craft.
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Forty years ago today Apollo 11 landed on the moon. When I have an open house at the observatory, one of the things people want to know is, can we see the landers that are left on the moon from the Apollo missions. I have to tell them no, too much atmosphere, and not enough telescope.

The scary thing is the 6% of the public who believe the landing was all just one big hoax. Now to answer both questions on the 40th anniversary…we’ve got pictures!!!!

All images credit: NASA/Goddard Space Flight Center/Arizona State University

NASA’s Lunar Reconnaissance Orbiter, or LRO, has returned its first imagery of the Apollo moon landing sites. The pictures show the Apollo missions’ lunar module descent stages sitting on the moon’s surface, as long shadows from a low sun angle make the modules’ locations evident.

The satellite reached lunar orbit June 23 and captured the Apollo sites between July 11 and 15. Though it had been expected that LRO would be able to resolve the remnants of the Apollo mission, these first images came before the spacecraft reached its final mapping orbit. Future LROC images from these sites will have two to three times greater resolution.

Apollo 11 Site, Click for Larger picture

Apollo 11 Site, Click for Larger picture

The Apollo 14 site shows even more detail in the full picture below and the magnified Captions

Apollo 14 Landing Site

Apollo 14 Landing Site

Apollo 14 Site showing foot path and instruments

Apollo 14 Site showing foot path and instruments

These pictures are reminder of a past era of NASA exploration, but the LRO’s mission is paving the way for the future. By returning detailed lunar data, the mission will help NASA identify future landing sites robots and astronauts, locate potential resources,like water, and measure the moon’s radiation environment while testing new technologies.

NASA Gravity Probe B July 19, 2009

Posted by neogajrhscience in Astronomy, General Relativity, Space Craft.
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Amy Brown has her blog at: http://neogajrhscience.wordpress.com/

Gravity Probe B measuring geodetic and frame shifting effects

What is Gravity Probe B?

Gravity probe B is a NASA mission first proposed in 1959 that was launched into space April 20, 2004. The probe contained a very accurate tracking telescope, and 4 gyroscopes. Its purpose was to test Einstein’s general theory of relativity, by measuring the amount of warp Earth causes in its surrounding spacetime (the geodetic effect) and the amount that Earth drags its local spacetime along as it rotates (the frame dragging effect). Data collection from the probe was completed in August, 2005, and data analysis has continued to the current date.

History of the Gravity Probe B Mission

Albert Einstein proposed his theory of general relativity in 1916, which linked the concepts of geometry and time with gravity.  Gravity, as we understood it from Isaac Newton, was an attractive force between bodies due to their mass.  Einstein proposed that, instead, gravity was a manifestation of the warping of spacetime around a body, which is also related to the body’s mass.  To visualize this warping of spacetime, imagine a bowling ball placed in the center of the fabric of a trampoline.  The mass of the bowling ball will pull the fabric down, warping the fabric in three dimensions.  The bowling ball, of course, is compared to any object in space, and the more massive the object, the greater the warp.

Warping of spacetime

Warping of spacetime

General relativity has stood up to several types of tests.  One of these involves the observational evidence of the precession of the perihelion of mercury, which shifts at the rate of 43 arc seconds per century.  After all other influencing factors have been accounted for, this shift is attibutable to the effect of general relativity from the mass of the sun.  Another type of test shows that light from distant objects bends as it travels past massive objects, such as the sun.  This has been measured both with visible light, and more accurately with radio waves. Gravitaional redshift is another method that has supported general relativity.  This measures the energy and time difference in objects at different positions in relation to earth.  GPS satellites must account for the difference in 38 microseconds per day from the height they are orbiting to the surface of the earth.  While these and other tests have provided substantial evidence to support general relativity, the evidence is not as precise as physicists would like it to be.  Scientists were striving to devise a way to test general relativity on a precision basis.

In 1959, Stanford Physics Departmment Chair Leonard Schiff and MITphysicist George Pugh both independently proposed testing general relativity using gyroscopes.  Schiff went forward with the idea, bringing on board other Stanford professores William Little, William Fairbank, and Robert Cannon.  Schiff, Fairbank and Cannon continued to research the idea from different angles, and this research led to a proposal to NASA in 1962.  NASA adopted the Gravity Probe project  in 1964, and Stanford remained the primary project base.

The concept of the Gravity Probe B

The concept of the Gravity Probe B

The idea behind Gravity Probe B was to construct a space probe containing gyroscopes aligned to a distant space object.  The spacecraft would surroound the gyroscopes, allowing them to remain in freefall.  As the spacecraft orbits the earth, any warping effect of the spacetime around the earth would cause a measurable orientation shift of the spinning gyroscopes.  This was to be measured in regard to two effects:  the geodetic effect, which is the simple warping of spacetime due to the earth’s mass, and the frame shifting effect, which is the effect caused by earth dragging spacetime along as it rotates.

The idea of the probe was a simple one, but the technology required was not.  More than a dozen new technologies had to be developed to make the probe work, and this took over 30 years to accomplish.  The spheres that make up the four gyroscopes hold a guiness world record as the roundest objects ever made, and required the invention of new manufacturing techniques to complete them.  They are made of quartz, refined to be homogeneous to within two parts in a million, and the sphericity is accurate to within 3 ten millionths of an inch. The spheres are coated with superconducting niobium.

Rotors

Gyroscope rotors, without and with niobium coating
Gyroscope rotors, without and with niobium coating

The gyroscopes are housed within a suspension system that is only 32 microns larger in radius than each gyroscope. Also attached to the housing is a SQUID magnetometer, which measures the tilt of the gyroscope spinning within as its magnetic field interacts with the sensor.  The satellite itself contains a nine foot long dewar (a large thermos) to contain the superchilled helium necessary to maintain the correct temperature to have the superconductive gyroscopes work properly.

Dewar

Dewar

In order to combat the small amount of heat that would enter the dewar, a special plug had to be designed to allow helium condensate to seep out into the outer layer.
In the late 1970’s and early 1980’s, the probe underwent a changeover form a research project to a flight mission project.  Lockheed Martin was brought in to help with the design.  It wasn’t until the late 1990’s, however, that the project was brought directly to NASA as a definite flight program.  It took nearly seven years to work out all the bugs.  Gravity Probe B was launched into orbit on April 20, 2004.

Launch of spacecraft

Launch of spacecraft

The Mission

In a nutshell, the spacecraft that took over thirty years to design and launch was going to test the general theory of relativity.  The spacecraft contains a tracking telescope.  This telescope is pointed at a distant star, IM Pegasi, as a guide star. A quasar would be the desirable tracking object, but the telescope would not be able to stay focused on one, so IM Pegasi was used, and its position would then be compared to a distant quasar during data analysis.  Once the telescope locks onto the position of the guide star, the gyroscopes are caused to sart spinning, and their alignment is matched to the alignmnet of the telescope. As the gyroscopes continue to spin, and the spacecraft orbits the earth, electrical signals between the gyroscopes and sensors in their housings are measured and sent back ot earth as raw data.

After the succesful launch, Gravity Probe B was in orbit 642km above the Earth.  Before the probe could begin collecting data, a four month period of initialization and check out was accomplished.  This period was supposed to be shorter, but several problems had to be corrected or accounted for before data collection could begin.  One problem was that the spacecraft had trouble tracking the starfield due to the roll of the craft. Another problem was the loss of two of the sixteen helium thrusters.  Setting the gyroscopes to spinning and aligning their spin axes with the guide star also caused some delay.  The gyroscopes were expected to spin at a faster rate than they actually were spinning, so many adjustments and calculations had to be made on the ground to achieve alignment.  One further delay during initialization occured whern the probe passed over the Earth’s south pole, and was bombarded by proton radiation from the sun.  The delay was caused by one of the spacecraft’s computers going down and having to be rebooted after the proton bombardment.  Because the initialization phase took quite a bit longer than anticipated, the decision was made to allow the data colection phase to be shortened.  The spacecraft continued to send data until August 15, 2005. The remaining six weeks until the helium was depleted and the mission was ended on September 29, 2005 were spent claibrating and testing the equipment on the spacecraft.

Data Analysis

Scientists associated with the Gravity Probe B mission have been analyzing the data since 2005.  In the ideal scenario, every instrument on the spacecraft would have performed without complication, and staightforward data  would have been provided.  Some of the systems on the probe functioned very well.  The dewar and the telescope performed exactly as expected.  Unfortunately, the gyroscopes did not.  The spheres themselves did spin extremely predictably, but the magnetic fields that they produced as they did so have been difficult to analyze.  The spin axes of the gyroscopes were effected by the torque of the spacecraft, and scientists have been trying to account for the data anamolies by identifying and quantifying them.  In terms of the two phases of data, the geodetic effect jumped out obviously, even from the raw data.  The measurement of the warping of space around earth was calculated by the data to be within 1% of the predicted 6606 milliarcseconds/year.   It is the measurement of the frame-shifting, however that is more effected by the data problems.  NASA has closed the project, but other funding sources are allowing the data analysis to continue.  Scientists with the project predict that with further analysis, they will be able to get the frame shifting data to within 3 to 5 percent of the expected 39 milliarcseconds per year.

The Legacy of Gravity Probe B

Regardless of the scientific outcome of the Gravity probe itself, the thirty year life of this research and space flight mission has provided the world with valuable benefits.  Ninety seven students received PhDs at Stanford and other universities working on this  project.  Technologies developed for the spacecraft have been used in other applications, such as the optical bonding and fused quartz technologies used on the gyroscopes.  Photo diode detector technology has helped to improve digital cameras for all of us.  The porous helium plug developed for Gravity Probe G has been used in other cryogenically sensitive missions such as IRAS and COBE.  Further, the attitude control technology in the spacecraft led to more accurate (1 centimeter) GPS now being used for automatic aircraft landing and automatic precision farming.  Scientists and teams associated with Gravity Probe B have won several awards, including the 2005 NASA group achievemnet award given to the whole team.  Gravity Probe B will remain into the future as one of the most memorable NASA missions in the history of the space program.

Further Information

The information contained in this article was obtained form the following sources:

http://einstein.stanford.edu/

http://www.nasa.gov/mission_pages/gpb/index.html

http://en.wikipedia.org/wiki/Gravity_Probe_B

Good bye Walter…. July 18, 2009

Posted by jcconwell in Astronomers, Astronomy, Space Craft.
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Legendary CBS news anchor Walter Cronkite, died June 17, 2009. Even though he hasn’t sat in the anchor chair for more than a quarter of a century, the impact on both journalism and the space program is felt even today.

Both objective and passionate, Walter Cronkite, personified the best in reporting, but especially science reporting. In my opinion he was as reponsible for making more scientist of my generation,  than any person. And “That’s the way it is”

History: Deep Space 1 June 30, 2009

Posted by gnhsphysics in Astronomy, Space Craft.
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EIU Astro is happy to have our first guest contributor for the summer, Paul Holder, whose blog is at: http://gnhsphysics.wordpress.com/

Deep Space 1 was launched from Cape Canaveral on October 24, 1998. During a highly successful primary mission the team tested twelve advanced high-risk technologies in space. In an extremely successful extended mission it encountered Comet Borrelly and returned the best images and other science data ever obtained from a comet. During its successful hyperextended mission, it conducted further technology tests. The spacecraft was retired on December 18, 2001.

Deep Space 1 was the first spacecraft to utilize ion engines. Ion engines use ejected ionized xenon gas instead of chemical propellants. Only a very small amount of xenon is ejected at a time. It may take four days or more just to use one kilogram of xenon. Becasue of this small ejection mass, the reaction force experienced by the spacecraft is also small. If you rest a piece of paper on your hand, the paper pushes on your hand about as hard as the ion engine pushes on the spacecraft.  The benifit of the xenon ion propulsion is that unlike chemical engines, which generally can only be operated for minutes, ion engines can be operated for years. Even though the force that acts on the craft is small, it is applied over a long period and produces a large impulse. The net effect of this is a large change in momentum (velocity), eventually attaining speeds far beyond the reach of chemical propellants.

Ion Propulsion System courtesy NASA

Deep Space 1, using less than 74 kg (163 pounds) of xenon, accelerated by about 4.3 kilometers/second (9600 miles/hour) over a period of 678 days. This is greater than any spacecraft has ever been able to change its speed and a longer duration than any previous propulsion system. This was attained while operating conservatively. DS1 could have achieved still higher velocity, but mission controllers had to fulfill defined mission objectives.

The team that developed and flew NASA’s Deep Space 1 spacecraft received the American Institute of Aeronautics and Astronautics’ prestigious Space Systems Award “For the outstanding performance of the team during design, implementation, test, operations, and extended mission including space flight test of 12 important, high-risk technologies.” The award was presented on April 2, 2003, during the Responsive Space Conference in Redondo Beach, Calif.