ISS Astronauts continue preparations for Spacewalk (EVA)

NASA astronaut Reid Wiseman, Expedition 41 flight engineer, works with tools and equipment on a spacesuit in the Quest airlock of the International Space Station in preparation for two spacewalks scheduled in October 2014.

Image Credit: NASA

With the first planned excursion of Expedition 41 just a week away, the International Space Station’s six-person crew spent Tuesday preparing spacewalking tools and equipment, while managing a packed agenda of scientific research and maintenance.

Commander Max Suraev of the Russian Federal Space Agency and the team of five flight engineers began the day at 2 a.m. EDT, and after some time for morning hygiene, breakfast and an inspection of the station, they conducted a daily planning conference with the flight control teams around the world.

Afterward, NASA astronauts Reid Wiseman and Barry Wilmore and European Space Agency astronaut Alexander Gerst went to work in the equipment lock section of the Quest airlock to stage the equipment they’ll need in order to prepare for spacewalks set for Oct. 7 and 15.

During the first six-and-a-half-hour spacewalk, slated to begin on Oct. 7 around 8:10 a.m., Wiseman and Gerst will transfer a previously uninstalled pump module from its temporary stowage location to the External Stowage Platform-2.

The two spacewalkers also will install the Mobile Transporter Relay Assembly (MTRA) that adds the capability to provide “keep-alive” power to the system that moves the station’s robotic arm between worksites.

The two astronauts will venture out on the station’s starboard truss to replace a voltage regulator that failed in mid-May.

Although the station has since operated normally on seven of its eight power channels, replacement of the regulator, known as a sequential shunt unit, is considered a high priority.

ESA astronaut Alexander Gerst's ISS training continues

ESA’s Columbus Control Centre (Col-CC) supports the European Columbus laboratory on the International Space Station. 

Col-CC is situated at the DLR German Aerospace Center facility in Oberpfaffenhofen, near Munich, Germany. 

The Control Centre is the direct link to Columbus in space. 

Its main functions are to command and control the Columbus laboratory systems, to coordinate operations of the European payloads on the Station and to operate the European ground communications network. 

Credit: DLR/T. Ernsting

An atmosphere of rising excitement can be sensed in the control centre: everything is ready for ESA astronaut Alexander Gerst's voyage to the International Space Station blasting off next Wednesday.

The Columbus Control Centre in Oberpfaffenhofen, near Munich, Germany has followed many launches since its inauguration 10 years ago – but no mission is routine.

The centres in Baikonur, Kazakhstan and Korolev, Russia are in the front line but ESA's site – callsign "Munich" – is responsible for the Columbus module and all European experiments.

Pedro Duque

"We cooperate with our international partners to make sure that the Space Station is ready to receive the Soyuz spacecraft and its crew," says ESA astronaut Pedro Duque, now head of the Flight Operations Office.

If the Station needs to rotate to allow the Soyuz to dock, for example, some European hardware might need to be switched off or risk interfering with the docking.

"Our teams run simulations a few times a year, including emergency scenarios," explains Pedro.

Operators also need to be ready to reconfigure Europe's Columbus laboratory if the planned six-hour flight is switched to a two-day approach, as happened to the previous Soyuz flight following a minor malfunction.

Pedro's experience as an astronaut comes in handy: "I can relate to the crew, and help flight controllers better understand the astronauts' perspective.

ESA astronaut Alexander Gerst during training on the plant gravity sensing experiment, at JAXA’s Tsukuba Space Center in Japan on 4 March 2014. 

As part of the International Space Station, the Japanese Experiment Module, called Kibo, was developed and tested at TKSC. 

At Tsukuba the astronaut training covers experiments that take place in Kibo. 

Alexander Gerst is flight engineer for Expedition 40/41, which will be launched to the International Space Station in May 2014 on a long-duration mission to run science experiments and maintain humankind’s space base. 

Credit: ESA–S. Corvaja, 2014

HADES: Continues search for Dark Matter Beyond the Standard Model

HADES at the GSI in Darmstadt, Germany searches for dark matter candidates. 

Credit: 3-D Rendering: A. Schmah /HADES

Although Dark Energy and Dark Matter appear to constitute over 95 percent of the universe, nobody knows of which particles they are made up.

Astrophysicists now crossed one potential Dark Matter candidate, the Dark Photon or U boson, off the list in top position.

This is the result of recent HADES experiments, where researchers from the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and from 17 other European institutes try to pin down the nature of Dark Matter.

These negative results, recently published in Physics Letters B, could even lead to challenges of the Standard Model of particle physics.

The interpretation of current astrophysical observations results in the striking mass-energy budget of matter in the universe: 75% Dark Energy and 20% Dark Matter. Only about 5% of the universe consists of "ordinary", baryonic matter.

Many attempts have been made to explain the nature of Dark Matter. Researchers believe that Dark Matter is comprised by hitherto unknown particles which do not fit into the Standard Model of particle physics.

The Standard Model is a theoretically sound quantum field theory with fundamental matter particles, such as quarks (bound in hadrons, e.g., baryons) and leptons (e.g., electrons and neutrinos), which interact via exchange of force-carrier quanta, called gauge bosons (e.g., photons).

Some of these species acquire their masses by the interaction with the Higgs boson.

While evidences for the Higgs boson were found recently at CERN, the Standard Model looks now complete when supplemented by some neutrino masses, and nothing else seems to be needed to understand the wealth of atomic, sub-nuclear and particle physics phenomena.

Nevertheless, Dark Matter appears not to be explained by any of the constituents of the Standard Model.

This status of the affair has initiated worldwide efforts to search for Dark Matter candidates.

Beyond the Standard Model
Searching a needle in the haystack is simpler: one knows both the wanted object (the needle) and the place (the haystack).

In the case of Dark Matter the object is unknown, and the localisation, e.g. in galactic halos, is also not constraining the loci of interest.

To specify the search goal one can envisage diverse hypothetical candidates, such as certain hypothetical particles beyond the Standard Model, which fulfill requirements qualifying them as constituents of Dark Matter.

Dark Energy drives the presently observed accelerated expansion of the universe. Dark Energy is homogeneously distributed and can be attributed to a cosmological constant or vacuum energy.

In extreme cases it may cause, in the future, such a sudden expansion that anything in the universe is disrupted, this would be the Big Rip.

Dark Matter, in contrast, is bumpy and is needed to explain the formation of the observed density distribution of visible matter in the evolving universe, evidenced by the hierarchy of structures from (super)clusters of galaxies, galaxies, stars, planets and other compact objects such as meteorites, etc.

Among the lists of candidates of Dark Matter is a hypothetical particle, often dubbed U boson or Dark Photon.

These nicknames refer to the underlying theory construction: a second unitary ("U") symmetry allows for quanta which are, in one respect, similar to photons, namely gauge bosons, but in another respect different from photons, namely attributing to these quanta a mass, making them to Dark Photons because of a very weak interaction with normal matter.

Very similar to photons the Dark Photons can decay into electron-positron pairs, if they have the proper virtuality.

Combining the chain of hypotheses one arrives at a scenario, where an "ordinary" virtual photon converts into a Dark Photon which decays afterwards into an electron-positron pair.

Background on HADES
HADES is an acronym of High-Acceptance Di-Electron Spectrometer.

It is an optimised detector system operated by a European collaboration of about hundred physicists at GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt.

HADES is aimed at investigating virtual photon signals emitted as electron-positron pairs off compressed nuclear matter to understand the origin of the phenomenon "masses of hadrons" and test it in some detail.

The highly sophisticated apparatus HADES has the capability to select electron-positron pairs, which can be attributed to primary sources, out of a huge background of other particles .

Read the full article here

More information: G. Agakishiev et al. (HADES Collaboration), Phys. Lett. B 731, 265 (2014) dx.doi.org/10.1016/j.physletb.2014.02.035

SpaceX Falcon 9 Launch: Dragon Preparations Continue

International Space Station Program officials and representatives of SpaceX decided Saturday to continue preparations for the launch of the Falcon 9 rocket and the Dragon cargo craft to the space station.

The launch is slated for Monday 14th April from Launch Complex 40 at the Cape Canaveral Air Force Station, Fla.

The launch will go ahead despite the failure Friday of a backup MDM computer communications component that provides redundancy for commanding the Mobile Transporter rail car on the truss of the station. 

A final decision on whether to launch Dragon Monday will not be made until another status meeting is conducted Sunday morning.

NASA has rescheduled its SpaceX prelaunch briefing allow for operational reviews in the morning.

It now will be held at 1 p.m. EDT at the agency's Kennedy Space Center in Florida. For updates on the schedule of events for Sunday, call the Kennedy News Center recording at 321-867-2525.

The component, called a multiplexer demultiplexer (MDM) is one of more than a dozen housed on the truss of the station that routes computer commands to various systems on the outpost.

The failure Friday to a box called EXT-2, a backup box to a prime component in the S0 truss that measures 10.5 x 14.9 x 16.4 inches and weighs 50.8 pounds, occurred during a routine health check of the device.

The prime multiplexer continues to operate flawlessly, and there has been no impact to station operations.

The crew was informed of the problem and is in no danger, continuing its normal complement of research work and routine maintenance.

A reboost of the station using the ISS Progress 53 thrusters was conducted Saturday as planned and placed the laboratory at the correct altitude for Soyuz crew landing and launch operations in May.

ISS Astronauts: Work continues to resolve Cooling Loop Issues for Cygnus arrival

Flight Engineer Doug Wheelock worked outside the International Space Station in August 2010 to install a spare pump module.

NASA engineers continued efforts Sunday to regulate temperatures in one of two cooling loops on the International Space Station affected by the malfunction last week of a flow control valve in a cooling pump on the station’s starboard truss.

A Flow Control Valve in the starboard Pump Module that enables the flow of ammonia to cool station systems stopped positioning itself properly last Wednesday, resulting in a drop of temperature in Cooling Loop A.

That necessitated the shutdown of some support systems on the station. The temperature must be warm enough in the cooling lines to allow the system’s heat exchangers to dissipate excess heat from the station through the external radiators on the complex.

The primary heat rejection capability for station systems shifted last week to Cooling Loop B that uses a fully operational Pump Module on the port truss.

Efforts overnight to fine-tune the position of an isolation valve associated with the flow control system in the Pump Module into a “sweet spot” to assist the faulty Flow Control Valve in regulating the affected cooling loop’s temperatures were still being evaluated as engineers continue to review the data, valve positioning techniques and additional methods of temperature management in the loop.

Meanwhile, parallel work is ongoing to either enable Orbital Sciences Corp. to launch its Antares rocket and the Cygnus cargo craft from the Wallops Flight Facility, Va. on its first resupply mission to the space station, or for Expedition 38 astronauts Rick Mastracchio and Michael Hopkins to mount a suite of spacewalks beginning Thursday to replace the faulty pump.

The International Space Station Program continues to keep both options on the table pending further engineering analysis and troubleshooting efforts on the station’s cooling system.

While the engineering work on the station’s cooling loop continued, technicians at Wallops prepared to load time-critical science cargo in the Cygnus spacecraft Sunday afternoon to preserve several days of launch opportunities beginning Thursday night.

The current schedule calls for the vehicle fairing to be installed on the Antares upper stage around Cygnus on Monday.

The Antares rocket and attached Cygnus are scheduled to rollout to the launch pad at Wallops in the wee hours Tuesday.

Meanwhile, aboard the space station, Mastracchio and Hopkins continued to prepare their spacesuits and other equipment in the Quest airlock Sunday should they be called upon to conduct spacewalks to replace the Pump Module.