NASA Twins Study | 340 Days in Orbit

On 1 March 2016, Scott Kelly returned from space landing with crew member cosmonauts Mikhail Kornienko and Sergey Volkov aboard the Soyuz return craft on the plains of Kazakhstan. They touched down at 10:26 pm CST. This very brief video shows the returning crew about ready to close their hatch, the Soyuz slowly departing the ISS, parachute descent of the Soyuz lander capsule, and emergence of the crew from the capsule.


During the State of the Union address to Congress by President Obama on 20 January 2015, astronaut Scott Kelly was introduced. He took part in a year long study involving Scott and his twin brother, astronaut Mark Kelly. Scott served on the International Space Station for 340 days since 27 March 2015 while Mark remained on Earth.





NASA | Scott Kelly left | Mark Kelly right


More details of the mission are available from CBS News consultant and long time space reporter William Harwood in his article.

Scott Kelly and Mark Kelly have been astronauts since August 1996. Mark is the husband of Gabrielle Giffords, former Democratic Congresswoman from Arizona who was shot in the head January 8, 2011, in an assassination attempt.


Time Dilation


Einstein Online

If you have studied some physics, you might remember the classic twin problem posed in the unit on Special Relativity. It goes like this. Twins will be involved in a long-term study of the time-dilation principle posed by Albert Einstein in 1905. One twin will stay home on Earth. Let’s call him Franco Fermi. The other twin will travel to a distant star and back. Let’s call her Flora Fermi. Flora’s ship will speed up to 86.67% of the speed of light, then coast to the star. Flora will slow down and immediately return, coasting back at the same speed as before.

Franco waited 30 years for the return of his twin sister. Upon her return, the hatch was opened. To the surprise of many, Flora and Franco looked quite different. Flora looked several years younger than Franco. When Earth clocks were compared to the clock on the ship, the ship and Flora have aged only 15 years.

Does time slow down for object moving close to the speed of light? Yes, it does. Many tests on sub-atomic particles bear this out.

Did the Kelly twins experience this same effect? Yes, but by an extremely small amount. The space station travels fast, but not at a significant fraction of the speed of light. It travels 0.0025% of the speed of light. During the 1 year Mark stayed home on Earth, his brother Scott will aged about 0.9999999998 years in space. That is a difference of less than 0.01 seconds in their ages over the year.


What Is NASA Studying?

There are 10 important studies. Each one is significant in their own right. In concert, they will add important information to our knowledge of the long term effects of space travel. And, as many past studies have shown, there are bound to be spin-offs that are of benefit to us all.

Science@NASA explains more about this mission in this brief video. It includes highlights of some of the studies to being performed.

From the press release in March 2014:

The following 10 selected proposals from 10 institutions in 7 states receive a combined $1.5 million during a three-year period:

  • Emmanuel Mignot, Stanford University School of Medicine, HERO Twin Astronaut Study Consortium (TASC): Immunome Changes in Space
  • Michael Snyder, Stanford University, HERO Twin Astronaut Study Consortium (TASC) Project: Longitudinal integrated multi-omics analysis of the biomolecular effects of space travel
  • Brinda Rana, University of California, Proteomic Assessment of Fluid Shifts and Association with Visual Impairment and Intracranial Pressure in Twin Astronauts
  • Susan Bailey, Colorado State University, Differential effects on telomeres and telomerase in twin astronauts associated with spaceflight
  • Fred Turek, Northwestern University, HERO Twin Astronaut Study Consortium (TASC) Project: Metagenomic Sequencing of the Bacteriome in GI Tract of Twin Astronauts
  • Andrew Feinberg, Johns Hopkins University School of Medicine, Comprehensive whole genome analysis of differential epigenetic effects of space travel on monozygotic twins
  • Christopher Mason, Weill Medical College of Cornell University, The Landscape of DNA and RNA Methylation Before, During, and After Human Space Travel
  • Mathias Basner, University of Pennsylvania School of Medicine, HERO Twin Astronaut Study Consortium (TASC) Project: Cognition on Monozygotic Twin on Earth
  • Stuart Lee, Wyle Laboratories, Metabolomic And Genomic Markers Of Atherosclerosis As Related To Oxidative Stress, Inflammation, And Vascular Function In Twin Astronauts
  • Scott Smith, NASA Johnson Space Center, Biochemical Profile: Homozygous Twin control for a 12 month Space Flight Exposure

6 thoughts on “NASA Twins Study | 340 Days in Orbit

  1. Scott’s return has been all the buzz here for some days, of course. I probably won’t make it for the livestream of his return to Houston tonight, but lots of people will. I’m certainly going to miss his daily photos and tweets, but now comes an equally important part of the study. I thought it was interesting that he returned home 2′ taller. Who knows what else they’ll discover?

    • I’ve enjoyed his reports, too. Tonight we watched the PBS show Year in Space.
      It was well done and included footage from yesterday.

      Yes. That taller thing is very common. According to Canadian astronaut Chris Hadfield, the return to Earth is sometimes a painful thing on the body as it gets used to the constant stress from gravity.

  2. […] Astronaut twins Mark and Scott Kelly participated in a study conducted by ten researchers on the effects of long duration space flight. Scott was aboard the International Space Station for 340 days while Mark remained on Earth. Scott returned to Earth 1 March 2016. For details about his return, read this previous post. […]

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