ISS year-long mission


The One-Year Mission was a scientific research project aboard the International Space Station, which studied the health effects of long-term spaceflight. Scott Kelly and Mikhail Korniyenko spent 340 days in space, with scientists performing medical experiments. Kelly and Kornienko launched on 27 March 2015 on Soyuz TMA-16M along with Gennady Padalka. The mission encompassed Expeditions 43, 44, 45 and 46. The pair safely landed in Kazakhstan on March 2, 2016, returning aboard Soyuz TMA-18M with Sergey Volkov. The mission supported the NASA Twins study, which helps shed light on the health effects of long duration spaceflight, which is of interest for Mars missions especially.
On 12 April 2019, NASA reported medical results from the NASA Twins study which demonstrated several long-lasting changes, including those related to alterations in DNA and cognition, when one twin was compared with the other.

Selection

In November 2012, NASA, the Russian Federal Space Agency, and their international partners selected two veteran spacefarers for a one-year mission aboard the International Space Station in 2015. The mission included collecting scientific data important to future human exploration of the Solar System. Kelly and Korniyenko already had a connection; Kelly was a backup crew member for the station's Expedition 23/24 crews, where Korniyenko served as a flight engineer.
The goal aboard the orbiting laboratory was to understand better how the human body reacts and adapts to the harsh environment of space. Data from the mission was intended to help inform current assessments of crew performance and health and determine better and validate countermeasures to reduce the risks associated with future exploration as NASA plans for missions around the Moon, asteroids and ultimately Mars.

Results

On 12 April 2019, NASA reported medical results, from the NASA Twins study, which demonstrated several long-lasting changes, including those related to alterations in DNA and cognition, when one twin was compared with the other.
The study also required the astronauts to keep a journal, and investigated the psychological effects of living in a confined space for an extended length of time. Kornienko said of his experiences on Expedition 23/24: "The thing you miss there most of all is the Earth itself, I missed smells. I missed trees, I even dreamt of them. I even hallucinated. I thought I smelled a real fire and something being barbecued on it! I ended up putting pictures of trees on the walls to cheer up. You do miss the Earth there."
Scott stated that he missed feeling changes in the weather while on the ISS.

NASA Twin Study

Effect of spaceflight on the human body

The International Space Station developed exercise equipment, including treadmills and resistance devices to limit muscle atrophy in a low gravity environment. Weightlessness causes body fluids in astronauts to accumulate in the upper half of the body, leading to facial edema and unwelcome side effects. One problem may be the low gravity affecting the body in unforeseen ways and it can be hard to detect the cause and effect of gravity on the body. Space seems to cause trouble for a number of body parts including bone, sometimes the eyes, and a classic problem is space sickness.

Longest time spent in space by other astronauts

and Musa Manarov spent 365 days in space on Mir from December 1987 to December 1988.
Sergei Avdeyev spent 379 days on Mir in 1999 and Valeri Polyakov spent 437 days on Mir in 1994-1995.
Prior to the Year Long Mission, the longest mission on the ISS was 215 days, by Mikhail Tyurin and Michael López-Alegría. Christina Hammock Koch holds the record for the longest single spaceflight by a woman at around 328 days.