Monthly Archive: February 2015

A walk around space with Barry and Terry

After 91 days of living in their new home in space they finally went outside Not to catch some fresh air of course…that would be quit dangerous!

US astronauts Barry Wilmore and Terry Virts commenced the first of three spacewalks  last Saturday. It was Barry’s second spacewalk after his first one last October and Terry’s first.

The two astronauts, already nicknamed the ‘cable guys’  have to rig cables on the International Space Station for new docking ports for commercial and international spacecraft called International Docking Adapters or IDA. They will be delivered on two Space-X  Dragon spacecraft in the near future.

The adapters are built by Boeing and will arrive separately as Dragon cargo that will dock to the Harmony Module or Node 2. Node 2 already has two Pressurized Mating Adapter (PMA) which are used to connect spacecraft and modules with different docking mechanisms. They resemble tunnels that connect to spacecraft.

The tasks for the U.S. spacewalks #29, #30, #31.

The tasks for the U.S. spacewalks #29, #30, #31.

The goal will then be to link each International Docking Adapters to a Pressurized Mating Adapter … imagine doing it with Lego, more or less!

But like with Lego there is a possibility that one piece, in this case the Pressurized Mating Adapter could be better used elsewhere. That is the case with PMA-3. The first International Docking Adapter is relatively easy to install: it is connected to PMA-2, which is installed on the Harmony Module facing the direction the Space Station moves.

The second International Docking Adapter requires more work.  The international adapter will be connected to PMA-3 but it first has to be moved from Node 3 Harmony to Node 2 Unity to face towards space.

Why all this work? The new docking adapters will be used to welcome the new commercial cargos from Space-X and Boeing , starting most likely from the last part of 2017. In the long run the two new Adapters will allow the Space Station to host one more crew from the present six.

In the meantime new cargo arrived at the Space Station bringing food, supplies and new hardware for the experiments.

It has been a busy period  for the astronauts living on the ISS that in a very short period has seen the arrival of Dragon and the depart of both Dragon and the last ever European cargo spaceship ATV-5. Progress 58, the Russian cargo just arrived at the Station, will stay docked to the Station until next August.

The astronauts have a lot of work to do in any case: two more spacewalks are expected this week and a new crew will soon arrive to start Expedition 43.

Stefano Sandrelli

Cover image: Terry Virts as seen from the Cupola of the ISS and photographed by Samantha Cristoforetti on Feb.21, 2015. Credits: ESA/NASA

For more pics of the U.S. spacewalk #29:

Don't panic


A balanced diet: the potential renal acid load

Research has shown that a more acidic diet seems to decrease the mineral content of your bones. This is in particular of interest for people who are inactive and have a lower mineral bone density. This is also of importance for astronauts during their missions since astronaut bones already have less loading in space so they suffer from reduced bone mineral density.

One might think that the potential renal acid load derives from the acids in the food we eat. The main nutrients affecting the acid load of a diet are protein, calcium, potassium, phosphorus and magnesium. An algorithm to calculate the potential renal acid load (PRAL)  was developed by Remer & Manz (J Am Diet Assoc 1995). They took into account the absorption rates of nutrients in the gastrointestinal tract as well as the metabolic processes in the body

PRAL (mEq/d) = 0.49   * protein (g/d)

+ 0.037 * phosphorus (mg/d)

– 0.021  * potassium (mg/d)

– 0.026  * magnesium (mg/d)

– 0.013  * calcium (mg/d)


The information needed to calculate a PRAL  is often found on food packaging. Another way is to take information from tables of nutritional values. Precalculated PRALs are available such as To calculate the total PRAL of a meal you just add the food items together.

Food that is high in protein content, such as meat, fish, milk or cereals are acidic while vegetables and fruits are generally more alkaline because of their high potassium content. Meat lovers are highly recommended to combine meat with large portions of vegetables or fruits to compensate for the acidity from meat’s high protein content.

Martina Heer

Protein and muscles | ZeroG science lab


Exercise in space with Samantha!

The most important effects of microgravity on the human body are losing bone density and deteriating muscle strength. Each astronaut on the International Space Station exercises 150 minutes every day in the “space gym” to minimise the effects of living in space. Astronauts can use several exercise machines to simulate training on Earth. One of these is the Advanced Resistive Exercise Device or ARED for friends. We asked ESA astronaut Samantha Cristoforetti to show and explain how ARED works…ready?


Not rocket science


Greetings, ATV!

Time for farewells!! The Dragon spacecraft left the International Space Station earlier this week and today ESA’s ATV spaceship with the catchy name Georges Lemaître detached from the Station and will plunge after several orbits into Earth’s atmosphere. Due to the enormous heat from friction caused by its deceleration through the upper layers of air layers the spacecraft will turn into a huge fireball –  a fitting end to the spacecraft that is named after one of the founding fathers of the Big Bang theory!

Unfortunately, this will be the last ATV – after five very successful missions, the project is now complete. At the Columbus Control Center (Col-CC) we provided for each flight the ground infrastructure and supplied our colleagues at ATV Control Centre in Toulouse, France, with data, video and voice connections to the International Space Station network. After ESA astronaut Samantha Cristoforetti and cosmonaut Alexander Samokutyaev closed the hatches of ATV yesterday, the Space Station was prepared for the last hours of undocking of ATVs. We turned off our little amateur radio station [] in Columbus as well as the external Rapidscat experiment [], any radio interference with ATV’s navigation from the International Space Station should be avoided.

Slowly the Space Station turned to an appropriate orientation for undocking. When the moment arrived the Space Station’s active position control was turned off completely: Georges Lemaître needs to push away from the Space Station without the mothership trying to compensate for this force.

Afterwards all that remained was for the astronauts to wave good-bye … atv foreverATVs are part of a large space fleet that supplies the International Space Station. When the American Space Shuttle withdrew from service the Russian Soyuz spacecraft became the only way to get people to the Space Station and back on Earth. Three astronauts share a small space – and so there is little room for other supplies.

Despite this there is enough transport capacity to supply the International Space Station with vital cargo: The Russian unmanned Progress cargo has been flying for years as well as the Japanese HTV and the European ATV. Relatively new in the family of cargo ferries are two unmanned American commercial vehicles: SpaceX’s Dragon and Orbital Science’s Cygnus. While the ATV and Progress ships fly to the International Space Station and dock on their own accord, the others need assistance from the Station’s robotic arm. They approach the Station and fly in formation together – not so easy with complex orbital mechanics to calculate – before being gently captured by the robotic arm and moved securely to a docking port. Only then can the astronauts enter and start unloading cargo. It is much more complicated to bring something from the International Space Station back to Earth. The ATV, HTV, Progress and Cygnus spacecraft have no heat shield or other systems that are needed to survive a reentry into Earth’s atmosphere: they are designed to burn up in the upper layers of the atmosphere of Earth. Because of this the astronauts load them full of trash from the International Space Station and they serve as cosmic garbage disposal. Aside from the manned Soyuz only the Dragon is designed to withstand the tremendous energy from decelerating at speeds of 23 faster than the speed of sound. Paradoxically it is more difficult to get things from the Space Station to Earth than vice versa.

Tom Uhlig, Columbus Flight Director at the DLR center in Oberpfaffenhofen/Germany

Cover image by ESA astronaut Samantha Cristoforetti: .

Don't panic


An ‘elegant’ interview

After my bad experience interviewing fruit-flies, today my boss came to me saying I should interview someone who has been referred to as “elegant”… “And transparent,” she added with a smile. She’s a good boss, my boss is. I know she trusts me and that she values my work. The fruit-fly experience is now in the past. So I dutifully phoned the number the boss gave me and transcribed. Good morning professor, thanks for agreeing to this interview with Outpost 42! My pleasure, for my colleagues and myself it is a duty and a pleasure to make a small contribution to science and its outreach. You are very kind, professor. I know you will take care of an experiment to improve the health of astronauts on long-duration missions. What is it? Together with other colleagues, I work on the EPIGENETICS experiment: we try to understand how living in weightlessness can induce inheritable genetic modifications without changes  in the DNA sequence. But DNA is genetic register is it not? If it does not change, it cannot transmit differences from past mutations. Am I wrong? Well, some changes that do not correspond to a changed DNA can be inherited. The DNA remains the same, but the way it is expressed changes. A simple comparison would be when different actors perform the same play. The script will remain the same, but its interpretation is different. The science that studies these kind of changes is called epigenetics. Aside from this example, where do you see such a mechanism in everyday life? A classic example is cell differentiation: some cells specialise, but do not change their basic DNA structure. Some recent studies suggest that epigenetic changes may also have an impact on aging and on tumors. Let’s go back to the astronauts and space. Why do you want to do this experiment in reduced gravity? We want to understand how a cell that has adapted to space can transmit its adaptation to the next generation of cells. Bones and muscles of astronauts undergo changes in long-duration missions: our experiment is aimed to better understand if there are changes at the level of each cell and what the link is between adaptation and mutation epigenetics. I’m curious to see how you conduct the experiment. In her blog Samantha Cristoforetti seems to be having a lot of fun with Epigenetics. It is because we are involved. Understandably so Professor, you and your colleagues are certainly charismatic people. What I meant to ask was with which organisms are you conducting the experiment? Please do not tell me that it is those arrogant fruit-flies! [laughs]. We do not need fruit flies, our involvement is enough. You and Samantha of course. I imagine that you follow our astronaut step by step from Earth as she deals with the organisms of study, are they bacteria? Look [he keeps laughing], there is a misunderstanding here. We are on the station together with Samantha. In what sense? In the only way possible. We are there with her: when we launched we were larvae. Then we awakened with a good bacterial nourishment: some of us were put in a centrifuge that simulates gravity while others were left free to float in zero-gravity. Once mature, we reproduced: the adults were taken away and put in the refrigerator (called MELFI) to be analysed on ground while the larvae continued eating and growing happily for five days. This process is repeated: adults are popped in the fridge and the second-generation larvae allowed to grow. And so on, for four generations… Why are you not saying anything? Have you lost interest? Professor … who you are you? I am a worm, of course. What? Worms? I’m talking on the phone with a worm? I am a Caenorhabditis elegans, in fact. I have the honour of being able to enjoy a certain elegance. Is it a problem? Think about it: we are just a millimetre long, and we are totally transparent, allowing researchers to observe our internal organs under a microscope easily. And we are almost all hermaphrodites. Hello? Hello? Anyone on the line? Mr. interviewer … we have to go, the MELFI awaits us: goodbye, then, we’ll tell Samantha you said “hi”!

Stefano Sandrelli

  To learn more about the Epigenetics experiment: Cover image: Caenorhabditis elegans — a millimeter-long roundworm with a genetic makeup scientists understand — will be central to a pair of Japan Aerospace Agency investigations into muscle and bone loss of astronauts on the International Space Station in the first few months of 2015. Image Credit: NASA

Don't panic


Vegetable proteins: health served on a plate

Variation, variation and more variation: this is the correct way to ensure we eay all the nutrients that our body needs. For this reason the one dish meal helps us make every meal as complete as possible: 50% of your carbohydrate intake should come in fruits or vegetables, while 25% of your carbohydrate intake should come from whole grains and the last 25% should come from protein. As a condiment you can use extra-virgin olive oil. Proteins can be of animal or vegetable origin. To make your diet as varied as possible it is good to alternate animal proteins with vegetable ones. Meat, fish and eggs bring all the necessary amino acids to the body for its proper functioning. Since meat and eggs are also high in fat, it is good to alternate them with vegetable proteins from greens. Beans, lentils, chickpeas, peas and other vegetables, especially when dried, are important sources of protein as well as containing other properties such as a high fibre content. While it is true that plant proteins have a high biological value, but you can complement the intake of amino acids via the one dish meal scheme, accompanying  vegetables with whole-grain products that contain proteins. Let’s make greens a central component of our daily diet! Filippo Ongaro Read more:

Not rocket science | Protein and muscles