## Space Station-Based Experiment Might Have Found Evidence of Dark Matter Destroying Itself

Since it was first proposed in the 1960s to account for all the “missing mass” in the Universe, scientists have been trying to find evidence of dark matter. This mysterious, invisible mass theoretically accounts for 26.8% of the baryonic matter (aka. visible matter) out there. And yet, despite almost fifty years of ongoing research and exploration, scientists have not found any direct evidence of this missing mass.

However, according to two new research papers that were recently published in the journal Physical Review Letters, we may have gotten our first glimpse of dark matter thanks to an experiment aboard the International Space Station. Known as the Alpha Magnetic Spectrometer (AMS-02), this a state-of-the-art particle physics detector has been recording cosmic rays since 2011 – which some theorize are produced by the annihilation of dark matter particles.

Like its predecessor (the AMS), the AMS-02 is the result of collaborative work and testing by an international team composed of 56 institutes from 16 countries. With sponsorship from the US Department of Energy (DOE) and overseen by the Johnson Space Center’s AMS Project Office, the AMS-02 was delivered to the ISS aboard the Space Shuttle Endeavour on May 16th, 2011.

Ostensibly, the AMS-02 is designed to monitor cosmic rays to see how much in the way of antiprotons are falling to Earth. But for the sake of their research, the two science teams also been consulted the data it has been collecting to test theories about dark matter. To break it down, the WIMPs theory of dark matter states that it is made up of Weakly-Interacted Massive Particles (WIMPS), protons and antiprotons are the result of WIMPs colliding.

By monitoring the number of antiprotons that interact with the AMS-02, two science teams (who were working independently of each other) hoped to infer whether or not any of the antiprotons being detected could be caused by WIMP collisions. The difficulty in this, however, is knowing what would constitute an indication, as cosmic rays have many sources and the properties of WIMPs are not entirely defined.

To do this, the two teams developed mathematical models to predict the cosmic ray background, and thus isolate the number of antiprotons that AMS-02 would detect. They further incorporated fine-tuned estimates of the expected mass of the WIMPs, until it fit with the AMS-02 data. One team, led by Alessandro Cuoco, was made up of researchers from the Institute for Theoretical Particle Physics and Cosmology.

Using computer simulations, Cuoco and his colleagues examined the AMS-02 data based on two scenarios – one which accounted for dark matter and one which did not. As they indicate in their study, they not only concluded that the presence of antiprotons created by WIMP collisions better fit the data, but they were also able to constrain the mass of dark matter to about 80 GeV (about 85 times the mass of a single proton or antiproton).

As they state in their paper:

“[T]he very accurate recent measurement of the CR antiproton flux by the AMS-02 experiment allows [us] to achieve unprecedented sensitivity to possible DM signals, a factor ~4 stronger than the limits from gamma-ray observations of dwarf galaxies. Further, we find an intriguing indication for a DM signal in the antiproton flux, compatible with the DM interpretation of the Galactic center gamma-ray excess.”

The other team was made up of researchers from the Chinese Academy of Sciences, Nanjing University, the University of Science and Technology of China, and the National Center for Theoretical Sciences. Led by Ming-Yang Cui of Nanjing University, this team made estimates of the background parameters for cosmic rays by using prior data from previous boron-to-carbon ratio and proton measurements.

These measurements, which determine the rate at which boron decays into carbon, can be used to guage the distance that boron molecules travel through space. In this case, they were combined with proton measurements to determine background levels for cosmic rays. They incorporated this data into a Bayesian Analysis framework (i.e. a statistical model used to determine probabilities) to see how many antiprotons could be attributed to WIMP collisions.

The results, as they state it in their paper were quite favorable and produced similar mass estimates to the study led by Cuoco’s team. “Compared with the astrophysical background only hypothesis, we find that a dark matter signal is favored,” they write. “The rest mass of the dark matter particles is ?20 – 80 GeV.”

What’s more, both scientific teams obtained similar estimates when it came to cross-section measurements of dark matter – i.e. the likelihood of collisions happening based on how densely dark matter is distributed. For example, Cuoco’s team obtained a cross-section estimate of 3 x 10-26 per cm³ while Cui’s team obtained an estimate that ranged from 0.2 5 × 10-26 per cm³.

The fact that two scientific teams, which were operating independently of each other, came to very similar conclusions based on the same data is highly encouraging. While it is not definitive proof of dark matter, it is certainly a step in the right direction. At best, it shows that we are getting closer to creating a detailed picture of what dark matter looks like.

And in the meantime, both teams acknowledge that further work is necessary. Cuoco and his team also suggest what further steps should be taken. “Confirmation of the signal will require a more accurate study of the systematic uncertainties,” they write, “i.e., the antiproton production cross-section, and the modeling of the effect of solar modulation.”

While scientists have attempted to find evidence of dark matter by monitoring cosmic rays in the past, the AMS-02 stands apart because of its extreme sensitivity. As of May 8th, the spectrometer has conducted measurements on 100 billion particles. As of the penning of this article, that number has increased to over 100,523,550,000!

Further Reading: PBS Nova Next, Ars Technica, Physical Review Letters, (2)

## Era of Space Shuttle Endeavour Ends with June 1 landing at the Kennedy Space Center

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KENNEDY SPACE CENTER – Space Shuttle Endeavour and her six man crew landed safely today at the Kennedy Space Center in Florida at 2:35 a.m. EDT following a 16 day journey of more than sixteen million miles.

The STS-134 mission marked the end of Endeavour’s space exploration career. It was the 25th and last space mission by NASA’s youngest orbiter. Altogether, Endeavour has logged 299 days in space, orbited Earth 4,671 times and traveled 122,883,151 miles.

The crew was led by Shuttle Commander Mark Kelly. Also aboard were Pilot Greg H. Johnson and Mission Specialists Mike Fincke, Drew Feustel, Greg Chamitoff and the European Space Agency’s Roberto Vittori. Vittori is the last non NASA astronaut to fly on a shuttle mission.

## AMS Now Attached to the Space Station, Ready to Observe the Invisible Universe

The long-awaited Alpha Magnetic Spectrometer, a particle physics detector that could unlock mysteries about dark matter and other cosmic radiation, has now been installed outside the International Space Station. It is the largest and most complex scientific instrument yet on board the orbiting laboratory, and will examine ten thousand cosmic-ray hits every minute, looking for nature’s best-kept particle secrets, searching for clues into the fundamental nature of matter.

“Thank you very much for the great ride and safe delivery of AMS to the station,” said Dr. Samuel Ting, speaking via radio to the crew on orbit who installed the AMS. Ting is the AMS Principal Investigator who has worked on the project for close to 20 years. “Your support and fantastic work have taken us one step closer to realizing the science potential of AMS. With your help, for the next 20 years, AMS on the station will provide us a better understanding of the origin of the universe.”

“Thank you, Sam,” Endeavour commander Mark Kelly radioed back, “I was just looking out the window of the orbiter and AMS looks absolutely fantastic on the truss. I know you guys are really excited and you’re probably getting data and looking at it already.”

By collecting and measuring vast numbers of cosmic rays and their energies, particle physicists hope to understand more about how and where they are born, since a long-standing mystery is where cosmic rays originate. They could be created in the magnetic fields of exploded stars, or perhaps in the hearts of active galaxies, or maybe in places as yet unseen by astronomers.

The AMS is actually AMS-02 – a prototype of the instrument, AMS-01, was launched on board the space shuttle in 1998, and showed great potential. But Ting and his collaborators from around the world knew that to make a significant contribution to particle science, they needed a detector that could be in space for a long period of time.

AMS-02 will operate on the ISS until at least 2020, and hopefully longer, depending on the life of the space station.

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The AMS will also search for antimatter within the cosmic rays, and attempt to determine whether the antimatter is formed from collisions between particles of dark matter, the mysterious substance that astronomers believe may make up about 22% of the Universe.

There is also the remote chance that AMS-02 will detect a particle of anti-helium, left over from the Big Bang itself.

“The most exciting objective of AMS is to probe the unknown; to search for phenomena which exist in nature that we have not yet imagined nor had the tools to discover,” said Ting.

Source: ESA, NASA TV

## Endeavour Blasts Off on Her 25th and Final Mission

[/caption]KENNEDY SPACE CENTER – The second time was a charm for Space Shuttle Endeavour as she blasted off this morning (May 16) from Pad 39 A at the Kennedy Space Center on her historic final mission under overcast skies after a two week delay caused by a heater malfunction in the orbiters critical hydraulic fuel lines.

The threatening clouds moved in over the pad in the last 30 minutes of the countdown and nearly derailed the launch. Forecasters had predicted a 70 chance of favorable conditions.

The Universe Today team of Ken Kremer and Alan Walters witnessed Endeavour’s exciting launch from the press site next to the world famous countdown clock. Check out our photo album here.

Shuttle Commander Mark Kelly and his five crewmates lifted off at 8:56 a.m. EDT Monday on the STS-134 mission which will deliver a state of the art particle physics detector to the International Space Station.

The $2 Billion Alpha Magnetic Spectrometer (AMS) could potentially revolutionize our understanding of how the Universe was born and evolved over time. The AMS is a world class science instrument sponsored by the United States and 15 countries around the globe. Nobel Prize Winner Samuel Ting of MIT leads the international science project. Endeavour’s three main engines roared to life six seconds before the twin Solid Rocket Boosters were ignited and pushed the shuttle off the pad atop a tremendous roar and brilliant flames shooting from Endeavour’s tail. The blastoff was flawless and majestic. Endeavour disappeared into the clouds at about T plus 25 seconds Nearly half a million people flocked to the Florida Space Coast to be a part of history and witness the launch of Shuttle Endeavour on her 25th and final mission to space. Many hotels were sold out for the night. Numerous folks staked out their claim to a prime view location along area waterways and beaches by camping out for the night or by arriving many hours early to avoid the crush and clogged local roadways. Kelly’s crewmates are Pilot Greg H. Johnson and Mission Specialists Mike Fincke, Drew Feustel, Greg Chamitoff and Roberto Vittori of the European Space Agency. This is the first shuttle flight for Fincke and Vittori. “This mission represents the power of teamwork, commitment and exploration,” Commander Mark Kelly said shortly before liftoff. “It is in the DNA of our great country to reach for the stars and explore. We must not stop. To all the millions watching today including our spouses, children, family and friends, we thank you for your support.” Both Finke and Vittori flew to space atop Russian rockets on their prior spaceflights. Vittori will be the last international astronaut to fly aboard a shuttle. Endeavour is slated for a 16 day mission to the International Space Station which will include the final four spacewalks for the space shuttle program. The STS-134 mission is the penultimate flight of the shuttle program and the 25th and final one for shuttle Endeavour, NASA’s youngest Orbiter. If you watched Endeavour’s May 16 blastoff, send me your launch and crowd photos to post in an STS-134 launch gallery here at Universe Today. ## Endeavour Unveiled for Historic Final Blastoff [/caption] KENNEDY SPACE CENTER – A humongous crowd numbering perhaps half a million excited people is expected to witness the historic final blast off of Space Shuttle Endeavour. Clocks are ticking down as the countdown enters the final phase before Monday morning’s liftoff (May 16) scheduled for 8:56 a.m. EDT from Pad 39 A at NASA’s Kennedy Space Center (KSC). Endeavour was unveiled for blastoff earlier today as a protective cocoon like structure was pulled away from the shuttle stack. The Rotating Service Structure (RSS) was retracted from around the orbiter starting at 11:45 a.m. over about 45 minutes and under a gorgeous blue sky. See my photo album In a lucky break, expected thunderstorms that could have delayed the retraction and launch preparations actually passed through the area overnight, much earlier than expected. Shuttle managers will gather at 11 p.m. tonight for a critical meeting and decision to give the “Go-No Go” directive to load the External Fuel Tank with supercold liquid hydrogen and liquid oxygen fuel that powers the shuttle main engines for the eight and one half minute climb to orbit. The tanking process is scheduled to begin at 11:36 p.m. There are no technical issues at this time that would prevent a launch. The weather outlook remains at “70 Percent GO”. The goal of Endeavour and her all veteran six man crew is to deliver the Alpha Magnetic Spectrometer (AMS) to the International Space Station. The$2 Billion AMS is a state of the art particle physics detector that will search for dark matter, dark energy and antimatter and seek to determine how the Universe was born and evolved.

The 134 mission is set to last 16 days and will feature the final 4 spacewalks of the space shuttle program.

The crew will wake up at 12 a.m. Monday. They depart for the launch pad shortly after 5 a.m.

Launch coverage begins on NASA TV tonight at 11:30 P.M. shortly before fueling commences:

www.nasa.gov/ntv

If you watch Endeavour’s launch, send me your launch and crowd photos to post in an STS-134 launch gallery here at Universe Today.
Looking to the Heavens with Endeavour; Launch Pad Photo Special
Endeavour Astronauts Arrive at Cape for May 16 Launch
NASA Sets May 16 for Last Launch of Endeavour; Atlantis Slips to July
Endeavour’s Final Launch further delayed another Week or more
On the Cusp of Endeavour’s Final Flight
Brush Fires Erupt at Kennedy Space Center during Endeavour’s Last Countdown
Commander Mark Kelly and STS-134 Crew Arrive at Kennedy for Endeavour’s Final Flight
President Obama to Attend Endeavour’s Last Launch on April 29
Shuttle Endeavour Photo Special: On Top of Pad 39A for Final Flight
Endeavour Mated to Rockets for Last Flight Photo Album
Endeavour Rolls to Vehicle Assembly Building for Final Flight

## Looking to the Heavens with Endeavour; Launch Pad Photo Special

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KENNEDY SPACE CENTER – Space Shuttle Endeavour is poised for launch as the countdown clock ticks down to a liftoff from Pad 39 A on Monday morning, May 16 at 8:56 a.m. EDT. The shuttle Mission Management Team (MMT) at the Kennedy Space Center (KSC) met today (May 14) and gave the green light to continue launch preparations for the STS-134 mission, which is the final flight of shuttle Endeavour.

The weather forecast remains at a 70 percent favorable chance of acceptable conditions on Monday, according to Shuttle Weather Officer Kathy Winters. The weather outlook drops to only 20 percent favorable on Tuesday in case of a one day delay. The weather rebounds to 80 percent favorable if the launch is postponed by 48 hours.

At a briefing for reporters at KSC today, shuttle launch managers were upbeat about preparations for the launch.

“We had a really good meeting today, unanimous consent from the Mission Management Team to press on with the launch countdown,” said Mike Moses, MMT chairman and manager of shuttle integration at KSC. “Everything’s in really great shape, really no issues at all.”

Moses added that no problems are expected with the heaters in the auxiliary power units (APU’s) that caused the launch scrub two weeks ago on April 29.

Shuttle Launch Director Mike Leinbach said, “The countdown is going extremely well and the team is ready to go. Tanking of the External Tank begins just prior to midnight. We are not working any issue at this time.”

Fueling of the External Tank with supercold liquid oxygen and liquid hydrogen starts at 11.36 p.m. Sunday night.

Leinbach said that local officials are expecting a crowd of about half a million people to descend on the Florida Space Coast area for the launch.

“You’ll recall for the first launch attempt on that Friday afternoon, the estimate was between 500,000 and 750,000,” he said. “So they’re not quite expecting that big surge, but it’ll still be a heck of a traffic jam after launch.”

Endeavour and her six man crew will deliver the $2 Billion Alpha Magnetic Spectrometer – a particle physics detector searching for dark matter, dark energy and antimatter – to the International Space Station during a 16 day mission that will include 4 spacewalks. After Endeavour was rolled out to the pad, I had an awesome opportunity to photograph Endeavour at the pad from stunning vantage points all around the launch pad from top to bottom. Herein is part 2 of my photo album focusing on my visit to the base of the shuttle stack on the mobile launch platform while looking to the heavens and standing directly beneath the External Tank and in between the Twin Solid Rocket Boosters. Part 1 of my photo album concentrated on the view from the upper levels and our visit to the White Room – where the astronauts board the shuttle orbiter to take their seats for the adventure of a lifetime. If you watch Endeavour’s launch, send me your launch and crowd photos to post in an STS-134 launch gallery here at Universe Today. NPR Radio interview including Ken here: Shuttle Fixes Will Take At Least One Week ## Endeavour Astronauts Arrive at Cape for May 16 Launch [/caption] KENNEDY SPACE CENTER – The all veteran crew for the last launch of Space Shuttle Endeavour flew back to Florida today for their second try to lift off into space on the STS-134 mission to the International Space Station. This follows the launch scrub called by Shuttle launch managers on April 29 caused by a malfunction of critical heaters inside one of the orbiters three auxiliary power units (APU’s) which power the ships hydraulics. The weather forecast for Monday morning launch is currently “70% GO” and liftoff is targeted for 8:56 a.m. EDT on Monday, May 16. Stormy weather and rain is expected to sweep across central Florida over the weekend and clear out in time for the launch. But Sunday’s rain could potentially delay the retraction of the Rotating Service Structure – which protects the shuttle from bad weather – for a short time. Shuttle Commander Mark Kelly and his five crewmates arrived at the Shuttle Landing Facility at the Kennedy Space Center early this morning (May 12) at 9 a.m. aboard the Shuttle Training Aircraft (STA) after flying in from the astronauts training base at the Johnson Space Center in Houston, Texas. “It’s great to be back,” said Kelly to the large crowd of reporters, including me, gathered to greet the crew. “We really appreciate all the hard work by the team that’s worked over the last couple of weeks to get shuttle Endeavour ready. We are really excited to be here, excited to launch, hopefully on Monday if the weather holds. Kelly is joined on the crew by pilot Greg H. “Box” Johnson and Mission Specialists Mike Fincke, Andrew Feustel, Greg Chamitoff and Roberto Vittori. Vittori is a European Space Agency astronaut and spoke first in his native Italian language and then in English. “Box” celebrated his 49th birthday today. “I can’t think of a more perfect way to spend my birthday then to come here with my crew a get ready to fly Endeavour next week.” He also thanked the teams for resolving the APU issues. ”Hats off to Dana Hutcherson and her team for preparing Endeavour for this flow and finally a special thanks to the APU team for all the hard work you’ve done getting us to this point. Kudos for solving it and getting us back on track.” Kelly and Johnson will fly practice landings in the STA in the remaining days prior to Monday’s launch. The STA is a modified Gulfstream II jet which handles like a space shuttle. Mission Specialist Mike Finke whipped out a camera and photographed the gaggle of media as we were photographing them – a rare and thrilling experience for all of us. Finke tweeted the photo of us a short time later – and is included here. Technicians at the Kennedy Space Center have been working around the clock since April 29 to determine the cause of the heater failure and fix the problems. The malfunction was traced to a switch box located in the aft section of the shuttle. Shuttle workers swaped out the ALCA -2 load control assembly box. Then they retested the new unit and qualified it for flight. Humongous crowds are again expected to travel to prime viewing locations around the Kennedy Space Center and pack the local hotels, roadways and beaches. Flocks of tourists are already arriving in anticipation on Monday’s launch. About 750,00 folks had swarmed to Florida for the April 29 launch attempt. STS-134 is the penultimate mission in the Space Shuttle Program. The last shuttle flight by Atlantis is expected to occur in early July, but a firm launch date has not yet been set. If you do attend Endeavour’s launch, send me your launch and crowd photos to post in an STS-134 launch gallery here at Universe Today. NPR Radio interview including Ken here: Shuttle Fixes Will Take At Least One Week ## NASA Sets May 16 for Last Launch of Endeavour; Atlantis Slips to July [/caption] KENNEDY SPACE CENTER – NASA managers set May 16 as the new launch date for the final flight of Space Shuttle Endeavour after technicians completed work to rewire and retest a switchbox in the orbiters aft compartment. Shuttle managers ordered the repair work following a heater malfunction that forced NASA officials to call off the planned April 29 launch. At a briefing for reporters today (May 9) at NASA’s Kennedy Space Center in Florida, Shuttle managers Mike Moses and Mike Leinbach announced that Endeavour’s last liftoff is now targeted for 8:56 a.m. EDT on Monday, May 16. “Right now, we’re in good shape,” said Shuttle Launch Director Mike Leinbach. “Endeavour’s looking good, the team is upbeat. I went to the meeting this morning and they’re ready to go. Hopefully, this time the heaters will work and we’ll be able to launch on time next Monday morning.” The STS-134 mission is the penultimate flight of the space shuttle program and will deliver the$2 Billion Alpha Magnetic Spectrometer to the International Space Station.

Endeavour’s last launch attempt on April 29 was scrubbed about four hours prior to blastoff when critical hydrazine fuel line heaters failed to turn on inside one of the orbiters three auxiliary power units (APU’s).

Technicians have been working around the clock to resolve the problems and determined that the likely cause of the heater failure was an electrical short inside the ALCA -2 load control assembly box located in the aft section of the shuttle (see photo).

They installed about 20 feet of new wiring, a new ALCA box and then retested all related systems over the past week and a half.

“We’ve replaced everything except the heaters, and we’ve wrung those out with at least five separate checks and full functionals afterwards and now have extremely high confidence that the problem is no longer on the ship or in any of the electronics,” said Mike Moses, the Shuttle launch integration manager at the Kennedy Space Center.

The APU’s control the shuttles hydraulics which power the steering of the main engines, wings, wheels and rudders during ascent and re-entry. The three units must all be fully functional before NASA can commit to any shuttle launch as part of the launch commit criteria (LCC). If the heaters fail during flight, the hydrazine can freeze and clog the fuel lines and render the hydraulics inoperative. A rupture in the lines could result in toxic hydrazine leaking into the shuttles aft engine compartment.

The potential launch window for Endeavour’s final flight extends through May 26, except for May 21.

The all veteran six man crew led by Shuttle Commander Mark Kelly is due to fly to the Cape on Thursday, May 12 from their training base in Houston. The STS-134 mission has been officially extended to 16 days from 14 days and will include 4 spacewalks.

The launch countdown will commence on Friday, May 13 from the beginning of the nominal 41 hour countdown sequence.

As a consequence of Endeavour’s delays, the launch of the very final shuttle mission of Space Shuttle Atlantis will likely be delayed to mid-July, although Moses and Leinbach did not give a specific target date.

NPR Radio interview including Ken here:
Shuttle Fixes Will Take At Least One Week