Personnel Files // Public Record

The Survivors

Six people. The longest stays in space in human history. These are the ones who actually lived it.

6 Records 3,000+ Days Logged Documented Costs

REC-001 // Single-Flight Duration Record

Valeri Polyakov 🇷🇺

Roscosmos / Institute of Biomedical Problems · Physician-Cosmonaut

Deceased · Sep 2022

Continuous Days

437

17h 38m

Mission

Mir · Soyuz TM-18 / TM-20

08 Jan 1994 → 22 Mar 1995

The longest single continuous spaceflight in human history. The record has stood for over thirty years.

Human Log

“We can fly to Mars.”

Polyakov insisted on walking from the Soyuz capsule unaided after landing on the Kazakh steppe. He had been weightless for 14 months. He wanted to prove a Mars crew could do the same. That question is exactly what the Awakening Protocol is built around.

Documented Cost on Return

> Significant loss of bone mineral density in hips, spine, and legs
> Substantial skeletal muscle atrophy, particularly in legs and back
> Cardiovascular deconditioning; recovered over following months

REC-002 // NASA Twin Study Subject

Scott Kelly 🇺🇸

NASA · U.S. Navy Captain (Ret.)

Retired

Single Mission

340

days

Mission

ISS Expeditions 43/44/45/46 · “Year in Space”

27 Mar 2015 → 01 Mar 2016

Paired with his identical twin brother Mark Kelly, a fellow astronaut who remained on Earth. NASA’s landmark Twin Study produced the first molecular dataset of long-duration spaceflight on a genetically matched control.

Human Log

“It was harder than I expected, by a lot.”

Kelly wrote about the year in his book Endurance. He described persistent skin inflammation, fatigue, and the psychological weight of knowing there was no way down.

Documented Cost on Return

> Telomere length changes and structural eye changes (edema, optic disc)
> Measurable cognitive slowing and gut microbiome shifts during flight
> About 7% of gene expression changes remained different from pre-flight levels six months after return. These are expression shifts, not permanent genetic alteration.

REC-003 // Most Cumulative Days by an American

Peggy Whitson 🇺🇸

NASA (Ret.) · Axiom Space · Biochemist

Active

Cumulative Days

650+

U.S. record

Mission Record

ISS Expeditions 5, 16, 50/51/52 · Axiom Mission 2

2002 → Present

289 days on her longest single mission (2016–17). First woman to command the ISS, and the first to do so twice.

Human Log

Holds the record for most spacewalks by a woman: 10 EVAs, totaling over 60 hours outside the station.

Returned to orbit in 2023 commanding a private Axiom crew, nearly two decades after her first flight.

Documented Cost on Return

> Cumulative radiation exposure among the highest in the astronaut corps
> Repeated bone density loss and recovery cycles across multiple missions
> Post-flight neuro-vestibular readaptation following each expedition

REC-004 // Most Cumulative Days in Space

Sergei Krikalev 🇷🇺

Roscosmos · Flight Engineer / Commander

Retired

Cumulative Days

803

six missions

Mission Record

Mir, Space Shuttle, ISS Expedition 1 & 11

1988 → 2005

Member of the first resident crew of the International Space Station.

Human Log

“The last citizen of the USSR.”

Krikalev launched to Mir in May 1991 as a Soviet cosmonaut. While he was in orbit, the Soviet Union dissolved. His return was delayed because the country that sent him no longer existed. He landed in March 1992 as a Russian citizen, having spent 311 days in space on that mission alone.

Documented Cost on Return

> Standard long-duration bone and muscle loss across repeated exposures
> Prolonged gravitational readaptation following the 1991–92 mission
> Psychological load of indefinite mission extension with no fixed return date

REC-005 // Most Spacewalks · Most EVA Hours

Anatoly Solovyev 🇷🇺

Roscosmos · Soviet/Russian Cosmonaut

Retired

Total EVA

82:22

hrs : min outside

Record

16 Spacewalks · 5 Missions

1988 → 1998

Holds the all-time records for most EVAs and most cumulative time performing extravehicular activity. No astronaut has spent more of their career working in hard vacuum.

Human Log

Master of the outside work. More than three and a half full days of his life spent in a pressure suit, tethered to a station, with nothing between him and vacuum but a visor.

Spacewalks remain among the highest-risk operations in crewed spaceflight: suit pressure, thermal extremes, decompression sickness, and no margin for tool error.

Documented Cost on Return

> Cumulative radiation dose from repeated unshielded EVA exposure
> Hand and shoulder strain characteristic of high-EVA-hour cosmonauts
> Physical load of operating for hours in a pressurized suit against its resistance

REC-006 // Longest Single American Spaceflight

Frank Rubio 🇺🇸

NASA · U.S. Army Lieutenant Colonel · Flight Surgeon

Active

Continuous Days

371

unplanned extension

Mission

ISS Expeditions 68/69 · Soyuz MS-22 / MS-23

21 Sep 2022 → 27 Sep 2023

Launched on a standard six-month rotation. In December 2022, his Soyuz MS-22 return capsule suffered a coolant leak after a micrometeoroid strike. A replacement Soyuz had to be launched uncrewed. His mission doubled in length.

Human Log

He missed his daughter’s entire senior year of high school.

Rubio has said that if he had known the mission would stretch to a full year, he would have declined it for family reasons. He did not get that choice. The hardware failed, and the only way home was to wait.

Documented Cost on Return

> Required assistance exiting the Soyuz capsule and during initial readaptation
> Months of post-flight rehabilitation for bone, muscle, and balance recovery
> Psychological strain of indefinite extension driven by hardware failure. The fracture timeline with no end date.

Sample Size Advisory

We are planning colony missions on a sample size of only a few dozen humans who have ever lived in microgravity for more than six months at a stretch.

Everything we know about long-duration spaceflight comes from them. The next generation of missions will push far beyond what any of them experienced.

What Space Does to the Body The First Hard Limits