Universe Today

March 30, 2010April 13, 2022 by Ken Kremer

3 Welds to Go for 1st Orion Pathfinder Vehicle

Orion Crew Module Forward Cone Assembly of the Ground Test Article being transported at the NASA Michoud Assembly Facility in New Orleans, La. in the same factory that developed Apollo's Saturn launch vehicles and the external tank for the space shuttle fleet. The 5 meter diameter cone weighs about 650 lbs. Lockheed Martin is the prime contractor for the Orion crew module. Credit: NASA

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Just three crucial welds remain to complete the structural assembly of the very first pathfinder Orion manned capsule – the Crew Module – known as the Ground Test Article (GTA) at NASA’s Michoud Assembly Facility in New Orleans.

The GTA is the first full-sized, flight-like test article for Orion. The Orion test capsule is being built by Lockheed Martin at Michoud as you read these words, even as President Obama seeks to completely terminate Project Constellation and Orion in his new NASA Budget proposal for 2011.

Yes, America’s Orion Crew Module program really is that close to achieving this key assembly milestone on the road to a US human spaceflight replacement and successor to the soon to be retired Space Shuttle. That fact is quite evident in the new NASA photos I obtained especially for this story. The GTA functions as a production pathfinder to validate production processes and tools for the actual human rated flight vehicle to follow.

Lockheed expects to complete the close out advanced technology welds for the GTA by May 2010 according to senior Lockheed officials I contacted. Structural proof testing of the Orion GTA vehicle will commence shortly thereafter.

Beyond that, John Karas, the Lockheed VP for Human Spaceflight told me in an interview that “Orion can be ready for crewed flights to low Earth orbit as early as 2013”.

Meanwhile, in the face of a rising chorus of harsh bipartisan Congressional criticism of the cancellation of Project Constellation and America’s Orion Crew Vehicle, NASA Administrator Charles Bolden continues to insist at multiple venues that, “There is no Plan B for Space Exploration. I strongly support the priorities and the direction for NASA that the President has put forward. I did not ask anybody for an alternative to the President’s plan and budget”.

The headline photo and others below illustrate the advanced status of the three major segments. The upper and lower module segments are to be robotically welded together by May 2010 using friction stir welding to create the structural framework of the first Orion pathfinder.

Orion Crew Module Aft Assembly in the 5505 weld fixture. The 5 meter diameter Aft Assembly weighs 1,885 lbs. Credit: NASA

At the moment, Lockheed is pressing forward with the Orion capsule utilizing the Congressionally approved NASA funding still available in the current fiscal budget as well as hundreds of millions more dollars committed by Lockheed and its partners, Karas said to me. “Over 4000 people are working on the Orion Project. Those jobs are at risk.”

Soon, the Orion and Constellation contractors will face tough decisions on whether to continue with testing and development of new science and technology breakthroughs … or begin massive personnel layoffs and abandon the wide ranging work in progress in order to preserve the remaining funds for shutdown activities.

“All work on Orion is proceeding according to the current contract schedule,” said Lockheed spokesman Kevin Barre.

The three major components of the Orion Crew Module GTA to be mated together are comprised of the Forward Cone Assembly, the Aft Assembly and the Crew Module Forward Bay Assembly and Tunnel. “These structural elements comprising the Orion GTA have undergone the meticulous application of strain gauges in preparation for loads and development testing”, says Barre. Hundreds of gauges have been placed in various positions to measure the overall vehicle strain during GTA testing.

“Inside the GTA is a backbone which resembles a stringer on a boat. That backbone will be installed in April before initial testing of the GTA begins at Michoud in May,” Barre amplified.

Orion Crew Module Tunnel and Forward Bulkhead comprise the Forward Assembly, minus the outer thermal protection system. The tunnel is to be mated to the top of the Cone Assembly. Astronauts will enter the Space Station through the tunnel after docking. The Forward Assembly and Tunnel weighs 370 lbs. Credit: NASA

After the testing for structural integrity, the crew module will be outfitted with the thermal protection systems and internal components necessary for subsequent static vibration, acoustics and water landing loads testing in flight-like environments. Environmental support components – similar in mass and volume to the flight articles – will also be installed. These internal components are being built both at Michoud and at other contractor work sites around the country. The testing results will be used to correlate sizing models for all subsystems on the vehicle and finalize the design.

Lockheed achieved another key technology milestone when the fabrication of the Orion composite heat shield was completed in February 2010. The 5 meter (16.4 ft) diameter Orion heat shield is the world’s largest heat shield structure ever built, and larger in size than the Mars Science Lab (MSL) and Apollo heat shields. It will be attached to the GTA in June 2010 upon completion of acceptance testing.

The cutting edge heat shield is critical to the protection of the spacecraft and crew from the extreme temperatures experienced during re-entry. See photo below of the heat shield – which seems to hover like a flying saucer – after its removal from the mold where it was fabricated in Denver.

The Orion composite heat shield structure appears to hover above its layup mold during removal. It is the world’s largest heat shield ever built and is 5 meters in diameter. Credit: Lockheed Martin

Final testing of the Orion Ground Test Article at Michoud is set to begin in the September 2010 timeframe.

Work has not yet begun on the service module which supports the GTA with life support supplies.

Orion is a frustum shaped vehicle, dubbed “Apollo on Steroids” by the previous NASA Administrator Mike Griffin due to its obvious similarity to the Apollo Command Module. At a diameter of 5 meters and measuring 3.3 meters tall, Orion would have 2.5 times the interior volume of Apollo.

Of course the continuation of all this high technology work and the fate of thousands of US jobs associated with it, is threatened by President Obama’s decision to cancel Orion at this advanced stage of development after $9 Billion has already been spent by NASA and the taxpayers on Project Constellation since 2004. At least another $2.5 Billion will be required just to shut down the program. It’s quite possible that even more money will be required as contractors assess their full shutdown costs.

The Constellation program comprises the Orion Crew Vehicle and the Ares 1 and Ares 5 booster rockets designed to return humans to the Moon, Mars and Beyond for the first time since the Apollo program ended in 1972.

Obama’s budget calls instead for starting over with the development of a new human spaceflight capsule by relying on commercial providers to develop ‘space taxis’ to ferry US astronauts into low Earth orbit and the International Space Station. After the Space Shuttle is retired following its final flight later this year, the US will have no domestic manned vehicles to propel people into space and will instead have to purchase astronauts seats on board the Russian Soyuz capsule for some $50 million apiece until a commercial US ‘space taxi’ is ready for launch.

What Is Static Electricity?

[/caption]Wonder why you sometimes get zapped when touching a doorknob especially during winter? People will tell you it’s a simple case of static electricity. But what is static electricity?

In some texts, static electricity is a term supposedly used for electricity that does not deal with moving charges. Actually, there is movement of charges. In fact, when you get zapped, charges are actually moving between your fingers and the doorknob. However, the movement is only brief compared to the current in a closed circuit.

So how do stationary charges allow people to get zapped? To understand this phenomenon, try to recall the particles that make up an atom. That’s right, the protons, neutrons, and electrons.

Of the three, electrons are easily removed from an atom since the forces that bind them to an atom are weaker than those that hold the neutrons and protons together in the atoms’ nuclei.

Now, there are some materials that easily lose their electrons compared to others. We’ve included a list below ranking some materials based on their ability to lose electrons. The one at the top has a greater tendency to lose electrons while the one at the bottom has the least.

human hands
glass
nylon
fur
silk
aluminum
steel
hard rubber
vinyl(PVC)
Teflon

Such a list is known as a triboelectric series. A true triboelectric series would have positives and negatives but we won’t go into that here.

Therefore, based on the list, if you rubbed a glass rod with a silk cloth, it is the glass rod that would lose electrons to the cloth. When this happens, the glass rod becomes positively charged, while the silk cloth (having gained excess electrons) becomes negatively charged.

Then when you draw the glass rod close to small bits of paper, the positively charged glass rod repels the electrons in the paper (pushing them to one side in the paper) and attracting the positive side. This allows the bits of paper to stick to the glass rod.

In the case of people getting zapped, they usually gain electrons when they walk across a carpeted floor. The interaction is between the carpet and the soles of their shoes but the overall charge of their bodies get affected. You can imagine them as walking negatively-charged bodies.

So, when they touch a metal door knob, the excess electrons readily leap from their hands to the metal knob and they get zapped.

Actually, static electricity is a rather lengthy physics topic that covers more than just the zapping phenomena. It includes discussions on induction, conduction, Coulomb’s Law, and electric fields, to mention a few. However, when a regular person asks, “what is static electricity?”, he most likely wants you to explain about the painful sensation he experiences upon touching a door knob.

Coulomb’s Law deals with charges. Universe Today has articles talking about the charge of the proton and the charge of the electron.

NASA also has some related stuff. Check out the following articles:
Charges
Killer Electrons

Here are two episodes at Astronomy Cast that you might want to check out as well:
Antimatter
The Search for Dark Matter

Sources:
Wikipedia
How Stuff Works
The Physics Classroom

March 30, 2010December 24, 2015 by John Carl Villanueva

What Is Sound?

[/caption]Light and sound are both waves. However, the former can travel through a vacuum while the latter cannot. So what is sound and how does it propagate as a wave?

Sound is actually a pressure wave. When an object vibrates, it creates a mechanical disturbance in the medium in which it is directly adjacent to. Usually, the medium is air. The medium then carries the disturbance in the form of oscillating and propagating pressure waves.

The frequency of the waves are dependent on the frequency of the vibrating source. If the frequency of the vibrating source is high, then the sound wave will also have a high frequency. The sounds that we hear, from the voice of the person right next to you, to the music coming from your iPod earphones, to the crashing noise of shattered glass, all come from a vibrating source.

As the sound waves propagate through a medium, the pressure at a localized region in the medium alternates between compressions and rarefactions (or decompressions). Thus, if at one instant, a region in the medium experiences compression, the regions adjacent to it along the line of propagation are expected to be experiencing rarefactions.

Then as time progresses, the region in question undergoes a rarefaction while those adjacent to it undergo compressions. Therefore, if no medium exists, then the compressions and rarefactions cannot occur.

Now, how does one hear sounds? Remember how a source has to vibrate to produce a sound wave, and how a vibrating medium (e.g. air) has to exist to allow the sound wave to propagate? In the same manner, the receiver of the sound has to have something that can vibrate in order to ‘interpret’ the sound carried by the vibrating medium.

In the case of our ears, our eardrums serve as the receivers. When the vibrating air reaches our eardrums, it causes our eardrums to vibrate as well. The eardrums then transmit these vibrations to tiny bones in the middle ear, and so on until they reach the inner ear where the oscillating pressures are converted into electrical signals and sent to the brain.

Our ears are sensitive to vibrations between 20 to 20,000 Hz. Normally, frequencies that are higher or lower than the range provided cannot be processed by our auditory system. Young kids however, are able to hear slightly higher frequencies. That means, the range over which we are sensitive to diminishes as we grow older.

We have some articles in Universe Today that are related to sound. Here are two of them:

Hypersonic
Supersonic

Speed of sound references, brought to you by NASA. Here are the links:

Tired eyes? Let your ears help you learn for a change. Here are some episodes from Astronomy Cast that just might suit your taste:

Sources:
Indiana University
Wikipedia

March 30, 2010April 26, 2016 by Tega Jessa

Oxygen Cycle

The oxygen cycle is the cycle that helps move oxygen through the three main regions of the Earth, the Atmosphere, the Biosphere, and the Lithosphere. The Atmosphere is of course the region of gases that lies above the Earth’s surface and it is one of the largest reservoirs of free oxygen on earth. The Biosphere is the sum of all the Earth’s ecosystems. This also has some free oxygen produced from photosynthesis and other life processes. The largest reservoir of oxygen is the lithosphere. Most of this oxygen is not on its own or free moving but part of chemical compounds such as silicates and oxides.

The atmosphere is actually the smallest source of oxygen on Earth comprising only 0.35% of the Earth’s total oxygen. The smallest comes from biospheres. The largest is as mentioned before in the Earth’s crust. The Oxygen cycle is how oxygen is fixed for freed in each of these major regions.

In the atmosphere Oxygen is freed by the process called photolysis. This is when high energy sunlight breaks apart oxygen bearing molecules to produce free oxygen. One of the most well known photolysis it the ozone cycle. O2 oxygen molecule is broken down to atomic oxygen by the ultra violet radiation of sunlight. This free oxygen then recombines with existing O2 molecules to make O3 or ozone. This cycle is important because it helps to shield the Earth from the majority of harmful ultra violet radiation turning it to harmless heat before it reaches the Earth’s surface.

In the biosphere the main cycles are respiration and photosynthesis. Respiration is when animals and humans breathe consuming oxygen to be used in metabolic process and exhaling carbon dioxide. Photosynthesis is the reverse of this process and is mainly done by plants and plankton.

The lithosphere mostly fixes oxygen in minerals such as silicates and oxides. Most of the time the process is automatic all it takes is a pure form of an element coming in contact with oxygen such as what happens when iron rusts. A portion of oxygen is freed by chemical weathering. When a oxygen bearing mineral is exposed to the elements a chemical reaction occurs that wears it down and in the process produces free oxygen.

These are the main oxygen cycles and each play an important role in helping to protect and maintain life on the Earth.

If you enjoyed this article there are several other articles on Universe Today that you will like. There is a great article on the Carbon Cycle. There is also an interesting piece on Earth’s atmosphere leaking into space.

There are also some great resources online. There is a diagram of the oxygen cycle with some explanations on the NYU website. You should also check out the powerpoint slide lecture on the oxygen cycle posted on the University of Colorado web site.

You should also check out Astronomy Cast. Episode 151 is about atmospheres.

March 30, 2010December 24, 2015 by Nancy Atkinson

Astronaut Explains Why We Should Return to the Moon

Astronaut Ronald J. Garan. Photo Credit: NASA

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The debate on why humans should or should not return to the Moon has been ongoing for years. Two weeks ago, I had the opportunity to hear astronaut Ron Garan speak eloquently on a subject he is passionate about, water sustainability on planet Earth. Subsequently, I read an essay Garan wrote about the importance of returning to the Moon. Although Garan originally wrote this essay before the cancellation of the Constellation program was announced, he has amended his thoughts to reflect the likelihood that the US won’t be returning to the Moon anytime soon. With Garan’s permission, we are re-publishing his essay in its entirety.

The Importance of Returning to the Moon
(The 8th Continent)
By Ron Garan
NASA Astronaut

On May 10th, 1869, a golden spike joined two railways at Promontory Point, Utah, and the first transcontinental railroad was completed. On January 14th, 2004, a new vision for our Nation’s space exploration program was announced that committed the United States to a long-term human program to explore the solar system starting with a return to the moon. On February 1st 2010, those plans to return to the moon were put on hold. Although our Nation has decided to postpone a return to the moon it is still important to acknowledge the moon’s relevance to life on Earth.

There is no doubt that the railroad changed the world. It opened up frontiers to discovery, settlement, and commerce. The railroad was the backbone for the industrial revolution that provided the largest increase in life expectancy and improvement in quality of life in history. Just as the industrial revolution brought about unprecedented improvements in quality of life so can a new age of space exploration and development, but this time with a positive impact on the environment. To begin a period of sustainable space exploration, both the public and private sectors of our Nation must seize the opportunity and continue on a path to the moon.

Artist impression of humans on the Moon. Credit: NASA

Since the Vision for Space Exploration was announced in 2004, there has been an on-going debate about the importance of taking the next step in space exploration, a return to the moon. The reasons for making this the next step include: fulfilling a compelling human need to explore; gaining a foothold on the moon to prepare for journeys to other worlds; easing the world’s energy problems; protecting the planet from disasters; creating moon-based commercial enterprises that will improve life on Earth, conducting scientific research; inspiring young people toward higher education, and utilizing space resources to help spread prosperity throughout the world.

We should not return to the moon for any one of these reasons, but for all of them and more. By first establishing the basic infrastructure for a transportation system between the Earth and the moon and a sustainable, semi-autonomous, permanent human settlement, we will open the door to significant benefits for all. Of course, any permanent lunar base must be economically and politically sustainable and therefore must provide tangible benefits and a return on investment.

Ron Garan ready for an EVA in June 2008. Credit: NASA

Exploration: Great nations accomplish extraordinary endeavors that help to maintain their leadership in the world. America’s history is built on a desire to open new frontiers and to seek new discoveries. NASA’s vision for space exploration acknowledges that, “Mankind is drawn to the heavens for the same reason we were once drawn into unknown lands and across the open sea. We choose to explore space because doing so improves our lives and lifts our national spirit.”
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Establishing a lunar infrastructure will challenge us to improve the reliability of space transportation and allow us to demonstrate exploration systems and concepts without leaving the relative safety of near-Earth space. Testing systems and concepts at a location that’s a three-day journey from Earth is a logical step before we make the leap of a six-month journey to Mars. Establishing a permanently occupied lunar base also will open the way to detailed study and use of lunar resources, which likely are significantly more economical than lifting all required exploration resources from the Earth’s surface.

Energy: Today, about 1.6 billion people on the Earth don’t have access to electricity. The World Bank estimates that 1.1 billion people live in extreme poverty which leads to 8 million premature deaths every year. In developed countries, higher quality of life is achieved only through a high rate of energy use. Increased energy supply is needed for economic and social development, improved quality of life, and to grow enough food to provide for the citizens of the developing world.

Unless something is done soon, the world will be faced with a crisis of enormous proportions. The United Nations estimates that world population will be approximately 9.1 billion by 2050 with virtually all growth in the 50 poorest countries. The choices that the global society makes to provide for future energy needs will have a profound effect on humanity and the environment.

The moon can supplement Earth-based renewable energy systems to meet future energy demand. Ample energy from the Sun reaches the moon and is not interrupted by weather, pollution or volcanic ash. Solar energy farms on the moon can “beam” limitless clean energy down to where it is needed on Earth or to satellites for relay to the Earth. There are also other potential sources of energy including platinum for fuel cells and an isotope called helium-3, which could be used in fusion reactors of the future.

Supplying energy from the moon will enable us to help provide the Earth’s energy needs without destroying our environment.

asteroid-flying-by-Earth — Artists impression of an asteroid flying by Earth. Credit: NASA

Protect the Planet from Disasters: There is a real risk to the Earth’s inhabitants from asteroid impacts and super-volcano eruptions. If a large object the size of Comet Shoemaker-Levy 9 that recently slammed into Jupiter were to hit the Earth, civilization could be destroyed. Much smaller asteroids could cause tremendous damage and loss of life. The moon is a superb location for early detection systems.

A super-volcano eruption is a geologic event of enormous explosive power to affect the global climate for years. Scientists estimate the last such eruption happened 74,000 years ago, and was 10,000 times more powerful than Mount St. Helens. Tremendous amounts of rock and ash were ejected into the air causing a six year long volcanic winter and a 1,000-year instant Ice Age, massive deforestation, disastrous famine, and near extinction of humankind. Scientists estimate that such a super-eruption will occur about once every 100,000 years.

The systems and technology that will be developed for life and work on the moon can be used to develop habitats and systems that could preserve Earth’s inhabitants in the event of a devastating eruption. These systems will also improve our ability to live in extreme environments and can be used to learn how to overcome limited resources and other environmental issues.

Astronaut Ron Garan takes a moment to pose for a picture during training for his April 3-20 stay inside the Aquarius Underwater Laboratory off the coast of Key Largo, Florida. Credit: NASA

Moon-Based Commercial Enterprises: When the early pioneers headed west and expanded our Nation, they did not carry everything with them that they would need for their journey. They “lived off the land” and we will also need to use those resources available to us along our journey, starting with the moon.

There are numerous moon-based commercial activities that could significantly offset the cost of a moon base. Just a few of these are lunar refueling or servicing stations for satellites, lunar mining and space tourism. These commercial activities would allow us to return national treasures from space and provide a significant return on our space investment.

Scientific research: The moon offers an incredible opportunity to further human understanding and discovery. Since the moon’s ancient surface is relatively undisturbed, study of its geology can help us better understand the geological history of Earth. Further, the moon’s vacuum environment can’t be duplicated on the Earth or in low-Earth orbit, and could lead to new materials, advanced alloys, medicines and innovative ways to deal with limited resources on Earth. Radio telescopes on the far side of the moon would be shielded from all radio signals (noise pollution) from Earth, allowing tremendous sensitivity increases and telescopes pointed at the Earth could identify and predict weather and climate changes.

If we return to the moon just for science and exploration then activities will be limited by the amount of money our nation is willing to devote. But, if we establish a sustainable, economically viable lunar base then our science and exploration will be limited only by our imagination.

Education: Our children are our best investment for the future, and our space program is a tremendous motivator. Our Nation has seen a steady decline in the number of students studying math and science. The space program can help turn this trend around. I can personally attest to the ability of the space program to encourage students based on the fact that I enrolled in math and science courses and began the pursuit of an engineering degree the day after the first space shuttle mission landed. The creation of a permanent lunar base will inspire millions of young people toward higher education and help maintain our Nation’s technological leadership.

Astronaut Ron Garan, STS-124 mission specialist, participates in the mission's first EVA in June, 2008. Credit: NASA — Astronaut Ron Garan, STS-124 mission specialist, participates in the mission's first EVA in June 2008. Credit: NASA

Resources and Other Benefits: Since we live in a world of finite resources and the global population continues to grow, at some point the human race must utilize resources from space in order to survive. We are already constrained by our limited resources, and the decisions we make today will have a profound affect on the future of humanity.

Using resources and energy from space will enable continued growth and the spread of prosperity to the developing world without destroying our planet. Our minimal investment in space exploration (less than 1 percent of the U.S. budget) reaps tremendous intangible benefits in almost every aspect of society, from technology development to high-tech jobs. When we reach the point of sustainable space operations we will be able to transform the world from a place where nations quarrel over scarce resources to one where the basic needs of all people are met and we unite in the common adventure of exploration. The first step is a sustainable permanent human lunar settlement.

Artist concept of the Orion capsule in orbit around the Moon. Credit: NASA

How should we go about this important undertaking? A good analogy to look at is the U.S. railroad system. The greatest obstacle for the first railroad developers was financial risk. Purchasing right of way, paying wages for large workforces and buying materials and equipment were prohibitively expensive. But the federal government stepped in, orchestrating massive land grants and other incentives. Once initial government investment was assured, enterprising developers invested enormous sums to bridge vast valleys and tunnel through enormous mountains.

Today we are faced with similar obstacles in the development and use of space for the benefit of humanity. Potential space developers face enormous up-front costs for high-risk, long-term returns on investment. To capitalize on the tremendous moon-based opportunities, our nation should establish the basic infrastructure for a transportation system between the Earth and the moon and a sustainable human settlement on the moon. Once this initial investment is made, commercial revenue-generating activities can be established. Just as our investment in the railroad, interstate road system, hydro-electric dams and other large federal projects have been paid back many times over by increased productivity and quality of life, so will our investment in lunar infrastructure.

We are poised on the doorstep of an incredible opportunity to benefit all of humanity. We have the technology and the ability to make this a reality — we need only the will to see it through. We need to choose a course toward the utilization of space to increase our available resources, global prosperity, quality of life, technological advancement, and environmental stewardship. Just as we look back and thank those before us for developing things most of us take for granted such as railroads and highways, the generations to come should be able to look back and thank us for committing to sustainable space exploration.

March 30, 2010April 26, 2016 by Nancy Atkinson

LHC Sets Record for Particle Collisions, Marks “New Territory” in Physics

The Large Hadron Collider at CERN. Credit: CERN/LHC

Event display of a 7 TeV proton collision recorded by ATLAS. Credit: CERN

Physicists at the CERN research center collided sub-atomic particles in the Large Hadron Collider on Tuesday at the highest speeds ever achieved. “It’s a great day to be a particle physicist,” said CERN Director General Rolf Heuer. “A lot of people have waited a long time for this moment, but their patience and dedication is starting to pay dividends.” Already, the instruments in the LHC have recorded thousands of events, and at this writing, the LHC has had more than an hour of stable and colliding beams.

This is an attempt to create mini-versions of the Big Bang that led to the birth of the universe 13.7 billion years ago, providing new insights into the nature and evolution of matter in the early Universe.
Continue reading “LHC Sets Record for Particle Collisions, Marks “New Territory” in Physics”

March 29, 2010December 24, 2015 by Ken Kremer

SpaceX Activates Station Communications System for Future Dragon Dockings

Illustration of SpaceX's Dragon spacecraft arriving at the International Space Station. ISS astronauts will command Dragon via the SpaceX-developed communications hardware recently installed aboard the ISS. Credit: NASA

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SpaceX announced today that a combined team of NASA and SpaceX personal had activated communications hardware aboard the International Space Station that will be crucial for enabling the docking of the Dragon unmanned cargo resupply vehicle being developed by SpaceX.

Start up of the new Ultra High Frequency (UHF) Communication Unit will allow ISS crewmembers to monitor and command approaching or departing Dragon spacecraft during cargo delivery missions to the massive 800,000 pound orbiting laboratory.

The communications hardware was delivered to the ISS aboard the STS 129 mission which blasted off in November 2009. The on-orbit checkout began in January 2010, when astronaut Jeff Williams, ISS Expedition 22 Commander, worked with ground-based team members at SpaceX headquarters and ISS mission control in Houston to power-up and check out the new system.

Astronaut Jeff Williams, Expedition 22 Commander, aboard the International Space Station with the SpaceX-developed controller for the Dragon spacecraft communications system. Credit: NASA

An additional series of tests was performed in March by SpaceX and NASA Houston using the new system to send communications between the ISS and the NASA Dryden ground station. This provided a baseline of the radio frequency performance and confirmed the first set of antennas performed as expected and is ready for mission operations.

The tests employed live video and telemetry links from the ISS to verify the hardware’s functionality, broadcast and reception signal strengths, and the system’s stability over long-duration operations.

SpaceX won a $1.6 Billion commercial contract from NASA under the Commercial Orbital Transportation Services (COTS) Program to conduct a minimum of 12 cargo flights aimed at delivering at least 20,000 kg of cargo to the ISS using the Dragon spacecraft. The first commercial resupply flights are set to start in 2011 after a series of three test flights start around May 2010.

Astronaut Jeff Williams, Expedition 22 Commander (top) aboard the International Space Station, and engineers at SpaceX Mission Control in Hawthorne, California, perform activation and testing of SpaceX's new communications system for operations with upcoming Dragon spacecraft resupply missions to the ISS. Credit: Roger Gilbertson / SpaceX

Dragon is slated to launch atop the SpaceX developed Falcon 9 rocket. Read my earlier story about the successful rocket engine test firing for the inaugural Falcon 9 rocket.

NASA is counting on the Dragon spacecraft to fill the giant cargo resupply void that will be created once the Space Shuttle program is retired later this year. Without a constant and reliable resupply train of food, spare parts and science equipment the ISS cannot fulfill its role as a world class science research facility. The massive orbiting outpost is nearing completion of its assembly phase and is rapidly transitioning to the science research phase for which it was constructed.

Pacman Eats The Death Star!

This figure illustrates the unexpected and bizarre pattern of daytime temperatures found on Saturn's small inner moon Mimas (396 kilometers, or 246 miles, in diameter). Credit: NASA/JPL/GSFC/SWRI/SSI

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Mimas has drawn a fair amount of attention with its “Death Star”-like appearance, but with new images from the Cassini spacecraft, this icy moon of Saturn has just gotten a lot more interesting. The highest-resolution-yet temperature map and images of Mimas reveal surprising patterns on the surface of the small moon, including unexpected hot regions that resemble “Pac-Man” eating the Death Star crater (officially known as Herschel Crater), as well as striking bands of light and dark in crater walls. “After much deliberation, we have concluded: Mimas is NOT boring,” said Carolyn Porco, Cassini imaging team leader, in an e-mail about the new images. “Who knew?!” And best of all, Porco added, “be sure you have a pair of red/green glasses handy ’cause you won’t want to miss peering into gigantic Herschel crater in 3D!”

Cassini collected the data on Feb. 13, and Porco said the team has spent some quality time poring over the images. She said the details in the moon’s craters that reminded the imaging team of features seen on Phoebe and Hyperion, plus the thermal signature is very peculiar and the team can’t yet explain it.

Herschel Crater in 3-D. Credit: NASA/JPL/Space Science Institute. Click for larger version.

“Other moons usually grab the spotlight, but it turns out Mimas is more bizarre than we thought it was,” said Linda Spilker, Cassini project scientist at JPL. “It has certainly given us some new puzzles.”

Scientists were expecting smoothly varying temperatures peaking in the early afternoon near the equator. Instead, the warmest region was in the morning, along one edge of the moon’s disk, making a sharply defined Pac-Man shape, with temperatures around 92 Kelvin (minus 294 degrees Fahrenheit). The rest of the moon was much colder, around 77 Kelvin (minus 320 degrees Fahrenheit). A smaller warm spot – the dot in Pac-Man’s mouth – showed up around Herschel, with a temperature around 84 Kelvin (minus 310 degrees Fahrenheit).

The warm spot around Herschel makes sense because tall crater walls (about 5 kilometers, or 3 miles, high) can trap heat inside the crater. But scientists were completely baffled by the sharp, V-shaped pattern.

“We suspect the temperatures are revealing differences in texture on the surface,” said John Spencer, who works with Cassini’s composite infrared spectrometer. “It’s maybe something like the difference between old, dense snow and freshly fallen powder.”

Denser ice quickly conducts the heat of the sun away from the surface, keeping it cold during the day. Powdery ice is more insulating and traps the sun’s heat at the surface, so the surface warms up.

Even if surface texture variations are to blame, scientists are still trying to figure out why there are such sharp boundaries between the regions, Spencer said. It is possible that the impact that created Herschel Crater melted surface ice and spread water across the moon. That liquid may have flash-frozen into a hard surface. But it is hard to understand why this dense top layer would remain intact when meteorites and other space debris should have pulverized it by now, Spencer said.

dark regions below bright crater walls and streaks on some of the walls are seen in this mosaic of Saturn's moon Mimas. — Dark regions below bright crater walls and streaks on some of the walls are seen in this mosaic of Saturn's moon Mimas. Credit: NASA/JPL/Space Science Institute. Click for larger version.

Icy spray from the E ring, one of Saturn’s outer rings, should also keep Mimas relatively light-colored, but the new visible-light images from the flyby paint a picture of surprising contrasts. Cassini imaging team scientists didn’t expect to see dark streaks trailing down the bright crater walls or a continuous, narrow pile of concentrated dark debris tracing the foot of each wall.

The pattern may appear because of the way the surface of Mimas ages, said Paul Helfenstein, a Cassini imaging team associate based at Cornell University, Ithaca, N.Y. Over time, the moon’s surface appears to accumulate a thin veil of silicate minerals or carbon-rich particles, possibly because of meteor dust falling onto the moon, or impurities already embedded in surface ice.

As the sun’s warming rays and the vacuum of space evaporate the brighter ice, the darker material is concentrated and left behind. Gravity pulls the dark material down the crater walls, exposing fresh ice underneath. Although similar effects are seen on other moons of Saturn, the visibility of these contrasts on a moon continually re-paved with small particles from the E ring helps scientists estimate rates of change on other satellites.

“These processes are not unique to Mimas, but the new high-definition images are like Rosetta stones for interpreting them,” Helfenstein said.

See more images of Mimas that were released today at the CICLOPS website.

Sources: JPL CICLOPS, email from Carolyn Porco

March 29, 2010April 26, 2016 by Nancy Atkinson

Carnival of Space #147

This week’s Carnival of Space is hosted by Bruce over at Weird Sciences.

Click here to read the Carnival of Space #147.

And if you’re interested in looking back, here’s an archive to all the past Carnivals of Space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to [email protected], and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, let Fraser know if you can be a host, and he’ll schedule you into the calendar.

Finally, if you run a space-related blog, please post a link to the Carnival of Space. Help us get the word out.

March 29, 2010December 24, 2015 by Nancy Atkinson

How Long Can the ISS Really Last?

ISS as seen by the departing Endeavour crew on STS-130. Credit: NASA

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How long can the International Space Station really operate – until 2020, or 2028 or beyond? I recently had the chance to talk with Mark Uhran, NASA’s Assistant Associate Administrator of the ISS. We were both attending a conference on water sustainability at Kennedy Space Center, but Uhran took the time to talk with me about the state of our space station, NASA’s new budget and how that might affect ISS operations, and — speaking of water — how is the urine recycling system working these days?

You can also hear an audio version of this interview on the March 28 edition of 365 Days of Astronomy.

Universe Today: How are things going as far the extension of the ISS? I heard there was recently a meeting with the international partners where they said it could be extended to 2028 if need be.

Mark Uhran: We’ve made the decision in the United States as part of the President’s budget proposal to Congress, so we’re over the hump here in the US. And then we began a series of meetings with the partners starting in Japan last week. Of course each of the partners has been working with us for the past 12-18 months, but they are fully prepared to approach their governments and ask for an extension. There are no technical obstacles to extending to at least 2020, and we’re also going to be doing an evaluation to what the ultimate lifetime of the ISS might be. That evaluation is in process. So we’re looking at whether we can go as long as 2028, but that remains to be seen.

Universe Today: Since we’re here talking about water, how are things going with the recycling system up there on the station. I know there have been some glitches here and there.

Uhran: The station has been a real testbed for developing regenerative water and air technologies. We knew at the time deploying these systems they would be in a testbed mode, and it would probably take about a year to shakedown all the systems and we are making steady progress towards doing just that. All the systems are working today – that’s not to say they will be working tomorrow. We certainly do expect them to go up and down throughout the course of the year as we fine tune them and work out the details. By the end of this year we hope to add a Sabatier (carbon dioxide reduction system) reactor that will allow us produce yet further water on orbit.

NASA"s Water Recovery System for the ISS. Credit: NASA

Hauling water is a very expensive proposition for us. Once the Sabatier is up there later this year, we’ll have basically the entire designed system deployed and I’m confident by this time next year we’ll have worked out all the filtration issues, the film formation issues, and precipitant issues and we’ll have this tuned so that it is basically available 90% of the time, which is an outstanding availability rate. So, this has been very worthwhile from our point of view not just because of the cost of hauling water to the space station but for the implications for human exploration beyond low Earth orbit.

Universe Today: The new NASA budget, which eliminates Constellation, how do you see that affecting space station operations?

Uhran: Well, space station is relatively small factor in that new budget. We’ve been extended, which is a major achievement from our point of view. But in terms of financial constraints, we are pretty well prepared now to go ahead and operate until the end of the decade, as well as to ramp up our research program on the station. With the assembly process being completed, the crew time now becomes available for supporting research. So most of our activities this year are geared towards repositioning our utilization program so that when the shuttle stops flying and the commercial cargo resupply services begin we are ready to ramp up that program aggressively, and that’s going very well.

Universe Today: I’ve been here at Kennedy Space Center for about a month and a half and a lot of the people here are talking about a possible extension for the space shuttle program. What are your thoughts on that?

Uhran: Well, the shuttle was certainly required for the assembly phase because we were hauling 20 metric ton elements up to orbit. It literally is the equivalent of a six-wheeler truck. But for the utilization phase, we can continue to maintain and operate the space station at much lower supply rates; typically 3 metric tons on a half a dozen to a dozen times a year. So there are other vehicles both that our international partners bring to the table as well as we’re hoping that the commercial US industry will demonstrate in the next 12-24 months that really will meet our needs once those are available. So although we’d all like to see the shuttles continue to fly forever, we really don’t have a requirement on space station for that kind of relatively heavy lift capability.

A close-up look at the Solar Alpha Rotary Joint. Credit: NASA

Universe Today: Another issue that has been sort of looming for the space station is the solar alpha rotary joints (SARJ). Any progress on understanding why they aren’t working as hoped?

Uhran: Well, they are working now. And the failure analysis has been completed. So we know the root causes of the problem. The most challenging mechanisms in any spacecraft system are rotating mechanisms. So the control moment gyros, the solar array rotary joints, the thermal radiator rotary joints – they are all rotating mechanisms. And we’re passing power through those mechanisms, which adds to the complexity. So we think that we have all these under control. It turned out with the SARJ that we have determined the cause of the failure, and we’re doing, really two things. We’re operating the system more gently – we ramp it up more slowly, we stop it more slowly. That doesn’t put as much load on the system. And we find that is applicable to all our systems. The more gently we can operate them the less loads they bear and the longer their lifetime. So we’ll be operating the system more gently and we’ll be lubricating them more regularly. So between those two approaches, we’re pretty confident we won’t have any more problems with the SARJ. We do have a couple of tricks in our pocket in the case that we do see further problems but we think we can get there with the two remedial actions we’ve got now.

Universe Today: To do the lubrication requires a spacewalk?

Uhran: It’s an EVA based activity, yes. It is relatively simple. And not even that time consuming. We were lubricating before, we’ll just increase the frequency.

Thanks to Mark Uhran for taking the time to talk with Universe Today. For more information on the International Space station, visit www.nasa.gov/station.