List of For All Mankind characters

For All Mankind is an American science fiction drama television series created and written by Ronald D. Moore, Matt Wolpert and Ben Nedivi and produced for Apple TV+. The series dramatizes an alternate history depicting "what would have happened if the global space race had never ended" after the Soviet Union succeeds in the first crewed Moon landing ahead of the United States. It premiered on November 1, 2019. In April 2024, the series was renewed for a fifth season, and it was announced that a spinoff series titled Star City is in development, focusing on the Soviet space program.

In an alternate timeline in 1969, Soviet cosmonaut Alexei Leonov becomes the first human to land on the Moon. This outcome devastates morale at NASA, but also catalyzes an American effort to catch up. With the Soviet Union emphasizing diversity by including a woman in subsequent landings, the United States is forced to match pace, training women and minorities who were largely excluded from the initial decades of U.S. space exploration. Each subsequent season takes place ten years later, with season two taking place in the 1980s, and season three taking place in the 1990s.

The series stars an ensemble cast including Joel Kinnaman, Michael Dorman, Sarah Jones, Shantel VanSanten, Jodi Balfour and Wrenn Schmidt. Sonya Walger and Krys Marshall had recurring roles in the first season before being promoted to the main cast for the second season, while Cynthy Wu, Casey W. Johnson and Coral Peña newly joined the cast, with Johnson and Peña playing older versions of characters that were portrayed by child actors in the first season. The third season saw Edi Gathegi also joining, while the fourth season added Toby Kebbell, Tyner Rushing, Svetlana Efremova and Daniel Stern.

The series features historical figures including Apollo 11 astronauts Neil Armstrong, Buzz Aldrin, and Michael Collins, Mercury Seven astronaut Deke Slayton, rocket scientist Wernher von Braun, NASA Administrator Thomas Paine, NASA flight director Gene Kranz, U.S. senator Ted Kennedy, and U.S. presidents Richard Nixon, Ronald Reagan and Bill Clinton with some of them portrayed by actors, while others appear through archival footage that is sometimes altered to reflect the changes in the alternate timeline.

The following is a list of characters that appeared on the television series.

Cast

 * List indicators
 * = Main cast (credited)
 * = Recurring cast (3+)
 * = Guest cast (1–2)

Edward Baldwin
USN Rear Admiral Edward "Ed" Baldwin, an astronaut. He was the commander of Gemini 7, Apollo 10, Apollo 15, Apollo 22, Pathfinder and Phoenix. He was the husband of Karen Baldwin and raised two children with her, Shane and Kelly, with the latter being adopted from Vietnam in the 1970s.
 * Portrayed by Joel Kinnaman

During Apollo 10, which was intended as a test run for Apollo 11, Ed and Gordo Stevens, his best friend and fellow astronaut, were only eight miles away from the Moon, but were instructed by NASA not to land. After the Soviets then landed on the Moon before Apollo 11, Ed and Gordo were widely criticised by the media, but Ed deflected the blame onto NASA, claiming that "NASA doesn't have guts anymore". He was then removed from Apollo 15 as a consequence of the interview, but was later reinstated as commander by Deke Slayton. At the same time, he also worked as an instructor and trained "Nixon's Women", a program that was started in response to the Soviets landing cosmonaut Anastasia Belikova on the Moon. Alongside Gordo and Danielle Poole, Ed was on the Moon with Apollo 22 when Apollo 23 exploded on the launchpad, extending their stay on the Moon until Apollo 24 would be ready. Ed is eventually left alone on the Moon after Gordo and Danielle are forced to return to Earth due to a medical emergency; the Soviets had their base only a few miles away from Jamestown, forcing someone to remain at Jamestown. In the meantime, Ed's son Shane had died in a car accident, which NASA decided to keep secret from Ed as they feared the news would have a major impact on his mental state along with the isolation. However, the Soviets leaked the news to him, after which he shuts off all communication with Earth. Shortly after, one of the Soviet cosmonauts, Mikhail Vasiliev, arrived at Jamestown and asked to be let in, as he did not have enough oxygen to return to his own base. Ed decided to trust him and obliged, however in the 1980s it is revealed that Vasiliev had placed a listening device in Jamestown. Vasiliev convinced Ed to answer NASA's calls and later helped him to prepare for the arrival of Apollo 24. The mission was a success and Ed returned to Earth while Ellen Wilson takes over Jamestown.

By 1983, Ed had been promoted to rear admiral and worked as Chief of the Astronaut Office at NASA. He then assigned himself as the commander of the Pathfinder mission, which was meant to escort the Sea Dragon resupply mission to Jamestown. During the mission, an incident occurred on the Moon where two of the Soviet cosmonauts were shot by US "moon marines". The Soviet Union declared a blockade on the Moon and threatened to shoot down Sea Dragon if they did not abort their mission. Ed threatened to fire back and destroy Buran, the Soviet shuttle, but Sally Ride, one of his crew members, refused to activate the weapon systems. He relieved her of her duties and she pulled a gun on him to force him back, but he ignored her threats and told her that he knows she won't shoot him. Ed activated the weapon systems but reconsidered Sally's warning that there must be another solution. He then decided to shoot down Sea Dragon himself, as to prevent the Soviets from committing an action of war by letting them destroy an American shuttle.

In 1992, Ed left NASA after not being selected as commander of the Mars mission. Instead he joined Helios Aerospace, a private space company, to command their Mars mission. He decided to take Danny Stevens—Gordo's son—with him, despite the warnings Danielle warning him of Danny's instability. After reaching Mars, Ed and Danny attempted to land during a heavy dust storm. Being ahead of NASA's Sojourner–1, he now had the chance to become the first human on Mars, but after nearly hitting a mountain and looking at Danny beside him, he decided to abort the mission, unwilling to be responsible for Danny's death. His decision allowed Sojourner 1, led by Danielle, to land first. After a landslide destroyed most of Helios' equipment and killed multiple astronauts and cosmonauts, Helios, NASA, and Roscosmos banded together for a joint mission to return the survivors to Earth. Meanwhile, Ed's daughter Kelly had started an affair with cosmonaut Alexei Poletov, who died in the landslide, and got pregnant. After months of repairing their equipment, Kelly had to be brought on board the Phoenix, Helios' ship in the Mars orbit, as soon as possible to save the baby, but as they had not produced enough fuel yet, only Kelly alone could be sent to Phoenix. Ed and the remaining survivors decided to stay on Mars and wait for a rescue mission, while Kelly and the Phoenix flew back to Earth. Ed flew Kelly towards the Phoenix with the repaired Landing Module and then managed to crash-land the Module back on Mars.

Ed is based on Apollo 10 commander Thomas P. Stafford.

Gordo Stevens
USN Captain Gordon "Gordo" Stevens, an astronaut. He was the Lunar Module pilot of Apollo 10, the commander of Apollo 18 and a member of the Apollo 22 crew, also known as Jamestown 2, the second mission that stayed at Jamestown Moon Base and was later stationed on the Base again with Jamestown 91. He was the husband of Tracy Stevens and had two sons with her, Danny and Jimmy.
 * Portrayed by Michael Dorman (seasons 1–2)

Gordo flew with his best friend Ed Baldwin for Apollo 10 and was criticised for not taking the opportunity to land on the Moon, which allowed the Soviets to come first. He was scheduled to fly with Ed again for Apollo 15, but was replaced by Molly Cobb and instated as commander of Apollo 18 again. Alongside Ed and also Danielle Poole, Gordo was on the Moon with Apollo 22, when the follow-up mission Apollo 23 exploded on the launchpad, extending their stay on the Moon until Apollo 24 would be ready. During their isolation Gordo suffered from extreme anxiety and hallucinations. The three first decided to keep his condition secret, as NASA would never allow him to fly again if they found out about his episodes of psychosis, but Ed decided to tell Houston the morning after another episode. In the same night, Danielle broke her own arm and they told NASA that it happened as an accident and that Danielle had to fly back to Earth for medical treatment. Gordo accompanied her as pilot, sparing him from him anyone finding out about his mental health problems, while Ed stayed on the Moon, as they could not leave Jamestown uncrewed. Back on Earth, he started seeing a psychologist and also told Tracy what really happened. Gordo later spoke to Danielle and told her that he wanted to reveal the truth to the whole world, that Danielle was the hero, not him, but Danielle told him that it would only ruin both their careers and to keep it secret.

By 1983, Gordo and Tracy had divorced and Gordo let himself go, believing that he would never fly again, but after seeing Ed and Danielle preparing for their missions, he pulled himself back and started working out with the goal to fly to the Moon again. He is eventually selected and returns to the Moon with Jamestown 91, where he also reunited with Tracy. When the Soviet cosmonauts attacked Jamestown to retrieve their captured comrade, Rolan Baranov, who had been shot and brought to Jamestown for medical treatment, Gordo and Tracy were in a chamber, talking about where their marriage went wrong, when they noticed that the inside of Jamestown was depressurized. Although the Soviets had blocked all communication to the Earth, the two managed to contact Houston via an older device from the original Jamestown Base. Margo Madison informed them that the reactor had been damaged and that there would be a nuclear meltdown soon if they did not activate the backup coolant systems. With no way to contact anyone else on Jamestown, the only way to prevent a meltdown was to activate the systems from outside. However, there were no spacesuits in chamber, forcing Gordo and Tracy to make impromptu spacesuits from duct tape, which would only protect them for a few seconds. They ran outside, turned the systems on and managed to reenter the chamber, but succumbed to their wounds caused by vacuum exposure. They were later found by the remaining astronauts on Jamestown and are posthumously awarded the Medal of Honor and buried at the Arlington National Cemetery.

Gordo is partially based on Apollo 10's lunar module pilot Eugene Cernan and on Mercury Seven astronaut Gordo Cooper.

Tracy Stevens
Tracy Stevens, an astronaut. She was the command module pilot of Apollo 25 and was later stationed on Jamestown Moon Base with Jamestown 89. She was the wife of Gordo Stevens and had two sons with him, Danny and Jimmy.
 * Portrayed by Sarah Jones (seasons 1–2)

In 1970, Tracy became an astronaut candidate as one of "Nixon's Women", a program that was started in response to the Soviets landing cosmonaut Anastasia Belikova on the Moon. She was one of four out of twenty women selected for the final program. Following the explosion of Apollo 23, which led to Ed Baldwin being stranded on the Moon, Apollo 24 was sent a few months later to return Ed to Earth. However, Apollo 24 had a malfunction while being in orbit and needed a new Saturn V FCC to be repaired. Tracy had already been selected as pilot of Apollo 25, whose original mission was to repair an astronomical satellite in Earth's orbit but changed to help Apollo 24. During the repairs the S-IVB of Apollo 24 accidentally ignited and launched the capsule, killing astronaut Harrison Liu and dragging the still-tethered Apollo 25 with it. Molly Cobb, the commander of Apollo 25, managed to free their ship and was catapulted into space, but Tracy managed to pilot Apollo 25 to catch and save Molly, after which they returned safely to Earth.

By 1983, Gordo and Tracy had divorced and Tracy had remarried. She returned to the Moon with Jamestown 89, where she reunited with Gordo, who arrived a while later with Jamestown 91. When the Soviet cosmonauts attacked Jamestown to retrieve their captured comrade, Rolan Baranov, who had been shot and brought to Jamestown for medical treatment, Gordo and Tracy were in a chamber, talking about where their marriage went wrong, when they noticed that the inside of Jamestown was depressurized. Although the Soviets had blocked all communication to the Earth, the two managed to contact Houston via an older device from the original Jamestown Base. Margo informed them that the reactor had been damaged and that there would be a nuclear meltdown soon if they did not activate the backup coolant systems. With no way to contact anyone else on Jamestown, the only way to prevent a meltdown was to activate the systems from outside. However, there were no spacesuits in chamber, forcing Gordo and Tracy to make impromptu spacesuits from duct tape, which would only protect them for a few seconds. They ran outside, turned the systems on and managed to reenter the chamber, but succumbed to their wounds caused by vacuum exposure. They were later found by the remaining astronauts on Jamestown and are posthumously awarded the Medal of Honor and buried at the Arlington National Cemetery.

Tracy is partially based on Trudy Olsen Cooper, a licensed pilot and the former wife of Mercury Seven astronaut Gordon Cooper.

Karen Baldwin
Karen Baldwin, Ed's wife with whom she had two children, Shane and Kelly, with the latter being adopted from Vietnam in the 1970s.
 * Portrayed by Shantel VanSanten (seasons 1–3; guest season 4)

In the 1970s, Karen often took care of Tracy's and Gordo's two sons Danny and Jimmy after Tracy followed her husband into the astronaut program. At the same time, she also developed a friendship with Wayne Cobb, husband of Tracy's fellow astronaut Molly Cobb, bonding over being the partners of astronauts. After Shane's death in a car accident in 1974, she decided not to tell Ed about Shane's death while he is still on the Moon, as NASA feared the effects the message would have on his mental state along with the isolation that he already had to endure. However, the Soviets leaked the news to him, after which he shut off all communications with Earth. The two eventually reunited after Ed's return to Earth to grieve together.

By the 1980s, Karen had become the owner of the Outpost Tavern, a bar usually visited by NASA astronauts, after previously having worked there. When their daughter Kelly, whom they adopted a few years after Shane's death, told them that she wanted to go the United States Naval Academy in Annapolis, Karen and Ed were opposed to the idea, which resulted in a family fight. Frustrated with her family life, she developed an affair with Danny Stevens, who worked at the Outpost. She told Ed about her affair right before he had to leave on another mission to the Moon, though she did not tell him that it was Danny. She later sold the Outpost to Sam Cleveland, Tracy's second husband, who wanted to turn it into a franchise.

Together with Sam Cleveland, she then founded Polaris Space Tours, a space tourism company. In 1992, they opened the Polaris space hotel with the wedding of Danny and Amber Stevens. However, the space station was hit by space debris and nearly almost destroyed. Following Sam's death during the Polaris hotel disaster, the company was dissolved and the space station was bought by Dev Ayesa, who wanted to rebuild the hotel into a spaceship for his Mars mission. Karen then joined his company, Helios Aerospace, to help him recruit astronauts and engineers from NASA, including her then ex-husband Ed. Following multiple incidents during the Mars race between Helios, NASA and the Soviet Union, the three factions band together for a joint mission. In the meantime, Jimmy Stevens became involved with a group of conspiracy theorists and anti-NASA activists, who planned a bombing of the Johnson Space Center. When Jimmy realized the truth about what he thought would just be a protest, he attempted to call his sister-in-law Amber but is knocked out and tied up by one of the conspirators. After Amber heard Jimmy's voice message and failed to call him back, she told Karen instead. Karen started searching for Jimmy and found him tied up in a van filled with explosives. Karen quickly confronted a security guard to inform him of the bomb and start an evacuation, but the bomb detonated before Karen could escape. After the explosion, Jimmy found her buried beneath debris, but she died before help arrived.

Ellen Wilson
President Ellen Wilson (née Waverly), an astronaut and the 41st president of the United States. She was a member of the Apollo 19 crew and commanded Apollo 24 as well as Jamestown Moon Base.
 * Portrayed by Jodi Balfour (seasons 1–3; guest season 4)

In 1970, Ellen became an astronaut candidate as one of "Nixon's Women", a program that was started in response to the Soviets landing cosmonaut Anastasia Belikova on the Moon. She was one of four out of twenty women selected for the final program. She is a closeted lesbian and entered a relationship with Pam Horton, a bartender who worked at the Outpost Tavern. Following the Apollo 23 incident, NASA is investigated by the FBI. When Ellen's friend Larry Wilson, a NASA engineer who is also a closeted gay, becomes a suspect, the two married to give each other cover, which however causes Pam to break up with her. Following the explosion of Apollo 23, which led to Ed Baldwin being stranded on the Moon, Apollo 24 is sent a few months later to return Ed to Earth. However, Apollo 24 had a malfunction while being in orbit and needed a new Saturn V FCC to be repaired. Following the deaths of Deke Slayton and Harrison Liu, Ellen was the only Apollo 24 crew member to arrive at the Moon, also leaving her stranded for a while, after Ed was sent back, whom she replaced. Shortly before Deke's death, she told him about her sexuality. He was initially disgusted, but then became more sympathetic, advising her to not reveal her secret to anyone since the world had too many people who thought like him and that it could ruin her career, but that he believes she has great things ahead of her.

In 1983, she was the commander of Jamestown Moon Base before returning to Earth. She briefly took over as the Administrator of NASA, following the sudden death of Thomas O. Paine in 1983. At the same time she reunited with Pam, hoping to rekindle their relationship, but she is rejected by Pam due to her fear that they could not have a calm relationship together, as Ellen has become a public figure.

Ellen started her political career in 1986, when she won a seat in the United States Senate for Texas. In 1992, Ellen and Larry have a son called Scotty. In 1993, she became the first female president of the United States after winning the 1992 United States presidential election against Bill Clinton. When American astronaut Will Tyler, a member of NASA's Mars mission, came out as gay, Ellen issued an executive order so that no American military personnel should be forced to disclose their sexual orientation. While Larry was investigated for having an affair with a man in 1995, Ellen forestalled the outcome by publicly coming out as a lesbian. Shortly after, she once again reunited with Pam.

She was re-elected as president in the 1996 United States presidential election. During her second presidency, she formed the Mars–7 Alliance to oversee the Mars colony and further events at space exploration and legalised same-sex marriage. In 2001, Ellen and Pam got married.

Margo Madison
Margo Madison, a NASA engineer and the first woman in Mission Control, who was mentored by Wernher von Braun. She later became Flight Director and Director of the Johnson Space Center and also mentored Aleida Rosales, who she convinced to join NASA to work in Mission control. She developed an affair with Soviet engineer Sergei Nikulov during the joint Apollo–Soyuz mission. The two regularly exchanged information in secret over the years to help each other. In 1992, the Soviet Union then used their relationship to blackmail her into giving them the plans for NASA's Mars mission, which they used to improve their own spacecraft and compete in the race for Mars. After the FBI starts investigating against her, she accepts an offer from Lenara Catiche, the director of Roscosmos, to flee from the United States to the Soviet Union, where she lives under the alias Margaret Reynolds.
 * Portrayed by Wrenn Schmidt

Margo is based on Frances Northcutt.

Molly Cobb
Molly Cobb, an astronaut, former Mercury 13 pilot and member of "Nixon's Women". As module pilot of Apollo 15, she became the first American woman in space. She also commanded Apollo 21 and 25, the earlier also known as Jamestown 1, the first crew to permanently occupy the Moon, where she is the one who discovers ice in the Shackleton Crater. She retired as an astronaut after saving Wubbo Ockels during a solar storm which made it likely for her to develop cancer due to the radiation. She later developed normal tension glaucoma, which led to her becoming blind. Nonetheless, she served as Chief of the Astronaut Office until she was fired by Margo Madison in 1992. She is later present during the bombing of the Johnson Space Center and survives the initial explosion, but reenters the destroyed building to help others who were injured. The Space Center was then renamed after her to honour her for her sacrifice.
 * Portrayed by Sonya Walger (seasons 2–3; recurring season 1)

Molly is based on Jerrie Cobb.

Danielle Poole
Danielle Poole, an astronaut and member of "Nixon's Women". She was a member of the Apollo 18 and 22 crews, which made her the first African American astronaut of NASA. She later commanded Apollo 75, which was part of the joint Apollo–Soyuz mission between NASA and the Soviet space program with the goal to bring NASA astronauts and Soviet cosmonauts together and shake hands, to encourage peace between the two nations during the height of the Cold War. While being in space, the mission was cancelled due to the high tensions between the two countries and Apollo 75 was called home, however she chose to ignore the command and contacted Soyuz–2 commander Stepan Petrovich Alexseev. They decided to manually proceed with the docking maneuver. After successfully docking, Danielle and Stepan met to shake hands, which ultimately helped to defuse the tensions between the two countries. In 1992, she was selected as commander of NASA's Mars mission, Sojourner–1.
 * Portrayed by Krys Marshall (season 2–present; recurring season 1)

Kelly Baldwin
Kelly Ann Baldwin (née Nguyễn Thị Hạnh, before adoption), a biologist and Ed's and Karen's adoptive daughter from Vietnam. As a child she was boarded on an American C-5A Galaxy transport aircraft as part of Operation Babylift to bring her and other children to the United States as refugees. She was one of 47 children who survived the plane crash. The Baldwin's then adopted her, after their son Shane had died in a car accident in 1974. In 1992, she worked at the McMurdo Station in Antarctica, before joining the crew of Danielle Poole's Mars mission. After the Sojourner saved the cosmonauts of Mars–94 and it became a joint mission, she entered an affair with cosmonaut Alexei Poletov. Following Alexei's death during the mission, she later gave birth to their child.
 * Portrayed by Cynthy Wu (season 2–present)

Danny Stevens
Daniel Gordo "Danny" Stevens, an astronaut and Gordo's and Tracy's son. He slept with Karen Baldwin while working at the Outpost Tavern and struggled to overcome his feelings for her, even after marrying Amber Stevens. He was stationed on Jamestown Moon Base and later became a hero, when he saved the Polaris space hotel from destruction and saved the lives of everyone in the hotel following his wedding on the space station. In 1992, he joined Ed Baldwin's Mars mission sponsored by Helios Aerospace. While on Mars, he is injured during drilling and is given Vicodin, after which he begins stealing stronger pain meds and develops an addiction. After Ed confronted him about his addiction, he grew resentful against him and caused a drilling accident which led to a landslide that killed several astronauts. After revealing his role in the disaster due to guilt, he is exiled to the North Korean landing module. He is mentioned to have died on Mars sometime before 2003.
 * Portrayed by Jason David (recurring season 1), Mason Thames (recurring season 1) and Casey W. Johnson (seasons 2–3; guest season 4)

Aleida Rosales
Aleida Rosales, the daughter of an illegal immigrant who is fascinated by space and was later mentored by Margo. Her father Octavio settled with her in Houston after the death of her mother. He worked as a janitor for NASA to help satisfy her interest in space. After her father is deported to Mexico after being initially suspected of spying for the Soviet Union, she was homeless from many years. She joined NASA as an engineer primarily to maintain her residency status, where she clashed with other employees due to her stubbornness, notably with Bill Strausser, a veteran mission controller, who temporarily quit his job after she called him "Peanut" in reference to an embarrassing episode in his past. Margo then forced her to apologize to Bill, after which he returned to NASA and the two became friends. By 1992, she was married to Victor Diaz, had a son, Javi, and was reunited with her father. However, her father showed signs of dementia, which she was unwilling to acknowledge. By 1994, she became Flight Director and directed NASA's Mars mission, Sojourner–1. She finds out about Margo's connection to the Soviets, which leads to the FBI starting an investigation despite her personal objections. After surviving the bombing of the Johnson Space Center by anti-NASA conspiracy theorists, she suffered severe post-traumatic stress disorder, causing her to take several months' leave of absence before resigning. She eventually partnered up with Kelly Baldwin to pursue private funding for a delayed NASA project, which led to the restoration of Dev Ayesa as CEO of Helios Aerospace.
 * Portrayed by Olivia Trujillo (recurring season 1) and Coral Peña (season 2–present)

Dev Ayesa
Dev Ayesa, the co-founder of "Helios Aerospace", a private space company with the goal to reach Mars before the NASA and the Soviet Union, for which he recruited Ed and Karen Baldwin and Danny Stevens. In 1987, Helios won a contract with NASA to mine Helium-3 from the lunar surface. The availability of clean nuclear energy led to an apparent curb in global warming. This breakthrough helped him fund the Phoenix, the space shuttle of his Mars mission, which was rebuilt from the Polaris space hotel after he bought the company from Karen Baldwin. He inherited his interest in space from his father, who worked as an engineer, building the Saturn V, but was fired following the explosion of Apollo 23.
 * Portrayed by Edi Gathegi (season 3–present)

Miles Dale
Miles Dale, a former offshore oil platform worker who pursues a new job opportunity on Mars.
 * Portrayed by Toby Kebbell (season 4)

Samantha Massey
Samantha Massey, a space worker and astronaut on the Mars colony, who shares quarters with Miles Dale.
 * Portrayed by Tyner Rushing (season 4)

Irina Morozova
Irina Morozova, a high-ranking Soviet official with strong ties to the KGB.
 * Portrayed by Svetlana Efremova (season 4)

Eli Hobson
Eli Hobson, the new administrator of NASA. A former auto industry CEO, he's been tasked with bringing the agency into the 21st century by President Al Gore.
 * Portrayed by Daniel Stern (season 4)

Introduced in season one

 * Deke Slayton, portrayed by Chris Bauer (season 1), one of the Mercury Seven astronauts and later the Chief of the Astronaut Office and Director of Flight Crew Operations. He selected himself as a member of the Apollo 24 crew. During the mission he dies of internal bleeding due to injuries sustained during the accidental S-IVB ignition and is then buried on the Moon.
 * Wernher von Braun, portrayed by Colm Feore (season 1), an aerospace engineer for NASA and former engineer for the Waffen-SS. He served as a mentor to Margo Madison, but is removed from NASA after it is revealed to the public that he knew about the treatment of slave labourers which built the V-2 rocket during the Second World War.
 * Gene Kranz, portrayed by Eric Ladin (season 1), NASA's Chief Flight Director. He died when Apollo 23 exploded during repairs in 1974.
 * Jack Broadstreet, portrayed by Michael Harney (season 1), a news anchor.
 * Thomas O. Paine, portrayed by Dan Donohue (seasons 1–2), the Administrator of NASA, serving twice under Republican presidents Richard Nixon and Ronald Reagan. Paine proposed the idea of an American military base on the moon that would later become Jamestown. He is relieved off his duty following the 1972 United States presidential election in which Richard Nixon was defeated by Ted Kennedy but is reinstated after Ronald Reagan wins the 1976 election. He later died on Korean Airlines Flight 007. In 1990, a space telescope was named after him to honour him.
 * Octavio Rosales, portrayed by Arturo Del Puerto (seasons 1, 3), an undocumented Mexican immigrant who settled in Houston with his daughter Aleida. He worked as a janitor at NASA's Johnson Space Center and used his job to encourage Aleida's interest in space. He is deported back to Mexico after his illegal status was discovered during the investigation of the Apollo 23 incident during which the FBI suspected him to be a Soviet spy. In 1992, he lives in the US again when Aleida works for NASA, helping to look after her son Javier. However, he begins to demonstrate early signs of dementia, which Aleida is unwilling to address.
 * Charlie Duke, portrayed by Ben Begley (season 1), an astronaut and member of the Apollo 16 crew.
 * Marge Slayton (née Lunney), portrayed by Rebecca Wisocky (season 1), Deke's wife.
 * Pam Horton, portrayed by Meghan Leathers (seasons 1–3; guest season 4), a barkeeper at the "Outpost Tavern" and a closeted lesbian who entered a relationship with Ellen Wilson but later broke up with her to pave the way for Ellen's political career. After finishing her master's degree, she became a teacher and published poet. After Ellen's public outing, the two reconciled and got married in 2001.
 * Buzz Aldrin, portrayed by Chris Agos (season 1), an astronaut and member of the Apollo 11 crew.
 * Michael Collins, portrayed by Ryan Kennedy (season 1), an astronaut and member of the Apollo 11 crew as well as the commander of Apollo 23. He retired after surviving the explosion of Saturn V during preparations for Apollo 23.
 * William "Bill" Strausser, portrayed by Noah Harpster (seasons 1–3; guest season 4), a mission controller who worked for NASA for over 30 years before leaving to join Helios Aerospace. He clashed with Aleida Rosales in season two, but later formed a friendship with her and mentored her. He retired following the bombing of the JSC, which left him paralyzed.
 * Tim "Bird Dog" McKiernan, portrayed by Nick Toren (seasons 1–2), a mission controller.
 * Hank Poppen, portrayed by Daniel Robbins (season 1), a mission controller.
 * Frank Sedgewick, portrayed by Dave Power (season 1; guest season 2), the Command Module pilot of Apollo 15 and later the commander of Jamestown Moon Base.
 * Roger Scott, portrayed by Spencer Garrett (season 1; guest season 2), a news anchor.
 * Shane Baldwin, portrayed by Teddy Blum (season 1) and Tait Blum (season 1), the son of Ed and Karen Baldwin, who died of injuries sustained in a car accident in 1974.
 * Jimmy Stevens, portrayed by William Lee Holler (season 1), Zakary Risinger (guest season 1) and David Chandler (seasons 2–3), the younger son of Gordo and Tracy Stevens. In 1994, he becomes involved with a group of conspiracy theorists and anti-NASA activists, believing that NASA lied about the circumstances of his parents' deaths.
 * Emma Jorgens, portrayed by Teya Patt (seasons 1–3), initially an MSC receptionist and later Margo's assistant.
 * Cata, portrayed by Krystal Torres (season 1), one of Aleida and Octavio Rosales' roommates in Houston.
 * Larry Wilson, portrayed by Nate Corddry (seasons 1–3), a NASA engineer and Ellen's eventual husband. He is a closeted gay. He and Ellen marry to give each other cover, after the FBI suspected him to be a Soviet spy during the investigation of the Apollo 23 incident. In 1993, he became the first ever First Gentleman of the United States. While in office, he entertained an affair with White House employee Jeremy Zielke.
 * Air Force General Arthur Weber, portrayed by Dan Warner (season 1), military liaison to NASA.
 * Wayne Cobb, portrayed by Lenny Jacobson (seasons 1–2; guest season 3), Molly's pot-smoking artist husband, who also developed a good friendship with Karen Baldwin, bonding over being the partners of astronauts.
 * Clayton Poole, portrayed by Edwin Hodge (season 1), Danielle's first husband, a Vietnam veteran who suffered from PTSD, which ultimately caused him to commit suicide.
 * Gloria Sedgewick, portrayed by Tracy Mulholland (season 1), the wife of Frank Sedgewick.
 * Harold Weisner, portrayed by Wallace Langham (season 1), the NASA administrator in the Ted Kennedy administration.
 * Irene Hendricks, portrayed by Leonora Pitts (seasons 1–2), the first female flight director, replacing Gene Kranz when he is made new director of Johnson space center before his death in the Apollo 23 incident.
 * Gavin Donahue, portrayed by James Urbaniak (season 1), an FBI agent, who investigated the Apollo 23 incident.
 * Andrea Walters, portrayed by Megan Dodds (season 1; guest season 2), a news anchor.

Introduced in season two

 * Air Force General Nelson Bradford, portrayed by John Marshall Jones (season 2; guest season 3), military liaison to NASA in the 80's and later Chairman of the Joint Chiefs of Staff under President Ellen Wilson.
 * Gary Piscotty, portrayed by Michael Benz (season 2), the pilot of Pathfinder
 * Helena Webster, portrayed by Michaela Conlin (season 2), a Marine pilot and astronaut.
 * Steve Pomeranz, portrayed by Tim Jo (season 2), an astronaut stationed on Jamestown Moon Base.
 * Paul Michaels, portrayed by Charlie Schlatter (season 2), a news anchor.
 * Amy Chang, portrayed by Linda Park (season 2), a news anchor.
 * Alex Rossi, portrayed by Scott Michael Campbell (season 2; guest season 3), an astronaut and the commander of Jamestown Moon Base in 1983.
 * Dr. Kouri, portrayed by Kayla Blake (season 2), an astronaut stationed on Jamestown Moon Base.
 * Sally Ride, portrayed by Ellen Wroe (season 2), an astronaut and member of the Pathfinder crew.
 * Paul DeWeese, portrayed by Alex Akpobome (season 2), an astronaut stationed on Jamestown Moon Base.
 * Nick Corrado, portrayed by Daniel David Stewart (seasons 2–3), an astronaut stationed on Jamestown Moon Base and later part of Helios Aerospace' Mars mission, where he died during a landslide caused by a drilling accident.
 * Vance Paulson, portrayed by Connor Tillman (season 2), head of the Marine detachment at Jamestown, who gets shot and killed by a cosmonaut during the 1983 conflict.
 * Charles Bernitz, portrayed by Zac Titus (seasons 2–3), a Marine and astronaut. He later joined a group of conspiracy theorists, believing that NASA lied about the events on Jamestown Moon Base and about the death of his friend Vance. He organized the bombing of the Johnson Space Center and also died in the explosion.
 * Jason Wilhelm, portrayed by Andre Boyer (season 2), a Marine and astronaut.
 * Steve Lopez, portrayed by Chris Cortez (season 2), a Marine and astronaut.
 * Sam Cleveland, portrayed by Jeff Hephner (season 2; guest season 3), Tracy's second husband and later Karen's business partner as joint owners of the Polaris space hotel, after he bought the Outpost Tavern from her to turn it into a franchise. He died in the Polaris disaster in 1992.
 * Sergei Orestovich Nikulov, portrayed by Piotr Adamczyk (seasons 2–3; guest season 4), a Soviet engineer on the Apollo–Soyuz team and later the director of Roscosmos, who develops an affair with Margo Madison. The two regularly exchanged information in secret over the years to help each other, which his superiors controlled. After they found out that he gave Margo more information than they allowed him, he was imprisoned until Margo forced them to bring him to the U.S. for their joined Mars mission, after the Soviet shuttle malfunctioned and their cosmonauts were saved by NASA's Sojourner–1. In 1995, Sergei and his parents are given political asylum in the United States, where he lived under the alias Sergei Bezukhov and worked as a high school teacher until Margo's return to the United States in 2003, when he contacted her again to warn her about Irina Morozova, who then orchestrated his assassination, which was framed as a suicide.
 * Nathan Morrison, portrayed by Josh Duvendeck (season 2), an astronaut and member of the Apollo–Soyuz crew.
 * Rolan Efimovitch Baranov, portrayed by Alexander Sokovikov (seasons 2–3), a cosmonaut, who is shot by one the of the space marines. After being brought to Jamestown for medical treatment, he asked for political asylum, as he wanted to leave the Soviet Union. His fellow Cosmonauts then attacked Jamestown, believing that he was kidnapped. In 1994, he works for NASA and is a member of Danielle Poole's Sojourner–1 crew, which made him one of the first humans on Mars.

Introduced in season three

 * Corey Johnson, portrayed by Sean Patrick Thomas (seasons 3–4), Danielle's second husband in 1992.
 * Isaiah Johnson, portrayed by Justice (season 3; guest season 4), Corey's son and Danielle's step-son.
 * Victor Diaz, portrayed by Jorge Diaz (seasons 3–4), Aleida's husband. Conflict between him and Aleida over how to address her father Octavio's dementia led to them being briefly separated.
 * Amber Stevens, portrayed by Madeline Bertani (season 3; guest season 4), Danny's wife.
 * Nuri Prabakar, portrayed by Sahana Srinivasan (season 3; guest season 4), Margo's new assistant.
 * Grigory Kuznetsov, portrayed by Lev Gorn (season 3; guest season 4), a cosmonaut and the commander of Mars–94, the Soviet Mars mission, before dying during the failed Kronos mission in 2003.
 * Lenara Catiche, portrayed by Vera Cherny (season 3; guest season 4), the director of Roscosmos.
 * Janice Haan, portrayed by Patricia Mizen (season 3), a reporter.
 * Karla Dunn, portrayed by Hailey Winslow (season 3), a reporter.
 * Edward Kline, portrayed by Ken Rudulph (season 3), a news anchor.
 * Richard Truly, portrayed by John Hartmann (season 3), the Administrator of NASA in 1992.
 * Javier Diaz, portrayed by Tiago Martinez (season 3) and Santiago Veizaga (season 4), Aleida's and Victor's son.
 * James "Jim" Bragg, portrayed by Randy Oglesby (season 3), the 43rd vice president of the United States, serving President Ellen Wilson, after winning the 1992 United States presidential election against Bill Clinton. Formerly the Governor of Idaho, he is known as an anti-science evangelical politician. After Wilson comes out in 1995, Bragg becomes one of her most vocal critics, launching an ultimately unsuccessful primary challenge in 1996. In 2003, Eli Hobson mentioned that Bragg was seeking the Republican presidential nomination for 2004.
 * Christine Francis, portrayed by Jessica Tuck (seasons 3–4), a news anchor.
 * Heather, portrayed by Cheyenne Perez (season 3), an employee of Helios Aerospace.
 * Ryan Bauer, portrayed by Larry Sullivan (season 3), a news anchor.
 * Jenna Leigh, portrayed by Allison Dunbar (season 3), a news anchor.
 * Will Tyler, portrayed by Robert Bailey Jr. (seasons 3–4), an astronaut and crew member of Sojourner–1. After landing on Mars, he came out as gay, which sparked a controversy, as gay people were not allowed to serve in the military. After returning to Earth, he worked in an administrative position at NASA.
 * Sunny Hall, portrayed by Taylor Dearden (season 3), a conspiracy theorist and anti-NASA activist, who befriends Jimmy Stevens and is involved in the bombing of the JSC.
 * Dick Gephardt, portrayed by Stewart Skelton (season 3), the U.S. Speaker of the House in 1995, who opposes President Ellen Wilson and wants to defund NASA.
 * Alexei Poletov, portrayed by Pawel Szajda (season 3), a cosmonaut and member of the Soviet Mars mission, Mars–94. He entered an affair with NASA astronaut Kelly Baldwin, but later died from injuries sustained during a landslide caused by a drilling accident.
 * Bill McGann, portrayed by Larry Clarke (season 3; guest season 4), a news anchor.
 * Adarsh Sethi, portrayed by Amol Shah (season 3), an astronaut and member of the Phoenix crew.
 * Louisa Mueller, portrayed by Anne Beyer (season 3; guest season 4), an astronaut and member of the Phoenix crew.
 * Lars Hagstrom, portrayed by Nick Boraine (season 3), an astronaut and member of the Phoenix crew.
 * Sandy Bostik, portrayed by Mandy Levin (season 3), an astronaut and member of the Phoenix crew.
 * Dr. Benjamin Harmon, portrayed by Ayinde Howell (season 3), an astronaut and member of the Phoenix crew.
 * Harold "Hal" Goodman, portrayed by William Cowart (season 3), a conspiracy theorist and anti-NASA activist, who is involved in the bombing of the JSC.
 * Dr. Dimitri Mayakovsky, portrayed by Goran Ivanovski (seasons 3–4; guest season 2), a cosmonaut and medical doctor stationed on the Moon in 1983 and later a member of the Mars–94 crew, the Soviet Mars mission, in 1995, where he is still stationed in 2003.
 * Isabel Castillo, portrayed by Ilza Ponko (season 3), a Cuban cosmonaut and member of the Soviet Mars mission, Mars–94. She died during a landslide caused by a drilling accident.
 * Richard "Dicky" Hilliard, portrayed by Blair Hickey (season 3; guest season 4), the co-founder of Helios Aerospace.

Introduced in season four

 * Lee Jung-Gil, portrayed by C.S. Lee (season 4; guest season 3), a North Korean cosmonaut, who became the first person on Mars, after the DPRK secretly send him and fellow cosmonaut Park Chol in a supposedly uncrewed probe. The DPRK kept the mission secret cover up a potential failed mission. Therefore, after the crash of the probe and Chol's death, Gil was also assumed to be dead until NASA commander Danielle Poole and Soviet commander Grigory Kuznetsov discovered him and returned him to their base.
 * Amanda Dale, portrayed by Shannon Lucio (season 4), Miles' wife.
 * Svetlana Zakharova, portrayed by Maria Mashkova (season 4), a co-pilot.
 * Artem, portrayed by Constantine Gregory (season 4), a newspaper man in Moscov.
 * Lily Dale, portrayed by Piper Rubio (season 4), Miles' and Amanda's younger daughter.
 * Sarah Dale, portrayed by Coco Day (season 4), Miles' and Amanda's older daughter.
 * Graciana Diaz, portrayed by Paris Rose (season 4), Aleida's and Victor's daughter.
 * Alex Poletov, portrayed by Ezrah Lin (season 4), Kelly's and Alexei's son.
 * Olga Poletova, portrayed by Irina Dubova (season 4), Alexei's mother, who helps Kelly raise Alex.
 * Jen Hughes, portrayed by S. Zylan Brooks (season 4), the flight director at NASA in 2003.
 * Tim, portrayed by Alex Cioffi (season 4), Eli Hobson's assistant.
 * Ilya Breshov, portrayed by Dimiter Marinov (season 4), a Mars space veteran and smuggler.
 * Palmer James, portrayed by Myk Watford (season 4), the director of Human Services on Happy Valley.
 * Joanna Chapman, portrayed by Rhian Rees (season 4), a British astronaut on Happy Valley.
 * Gerardo Ortiz-Niño, portrayed by Salvador Chacón (season 4), a space worker, who shares quarters with Miles Dale and Samantha Massey.
 * Rich Waters, portrayed by Moses Jones (season 4), a space worker.
 * Maya Estime, portrayed by Jo Kelly (season 4), a space worker, who shares quarters with Miles Dale and Samantha Massey.
 * Cho Byung Ho, portrayed by Charles Kim (season 4), the North Korean commander on Happy Valley in 2003.
 * Charlie Parfitt, portrayed by Michael Lee Joplin (season 4), a space worker.
 * Petros Khorenatsi, portrayed by Nick Gracer (season 4), a space worker and smuggler.
 * Faiza Khatib, portrayed by Noor Razooky (season 4), a space worker and smuggler.
 * Vera Martil, portrayed by Danielle Nottingham (season 4), a news anchor.
 * Mike Bishop, portrayed by Billy Lush (season 4), a NASA astronaut and team leader on Happy Valley who is revealed to be an undercover CIA agent.
 * Tatyana Volkova, portrayed by Ania Bukstein (season 4), a Roscosmos engineer.
 * Leonid, portrayed by Emil Markov (season 4), a high-ranking Roscosmos official.
 * Luka Gurino, portrayed by Sebastiano Pigazzi (season 4), a space worker.
 * Geraldine Middaugh, portrayed by Steph Evison Williams (season 4), a space worker.
 * Timur Avilov, portrayed by Nikita Bogolyubov (season 4), a space worker who is revealed to be an undercover KGB agent.
 * Veronica "Ronnie" Hunt, portrayed by Tess Lina (season 4), a Helios worker on Happy Valley and one of the strike leaders who became part of Dev Ayesa's plan to steal the Goldilocks asteroid.
 * Ravi Vaswani, portrayed by Vinny Chhibber (season 4), a NASA engineer, astronaut and pilot of the Ranger-2 mission to capture the Goldilocks asteroid.
 * Holly "Sparks" Edmondson, portrayed by Cindy Jackson (season 4), a Helios worker on Happy Valley who became part of Dev Ayesa's plan to steal the Goldilocks asteroid.
 * Nate Lowry, portrayed by Sean Patrick Murphy (season 4), Security personnel on Happy Valley
 * Nina Roxhenkova, portrayed by Katarina Morhacova (season 4), a Soviet cosmonaut.
 * Dr. Seth Razack, portrayed by Ely Henry (season 4), a mission controller.
 * Maximus Taylor, portrayed by Elliott Ross (season 4), an ESA astronaut on the Ranger.
 * Park Chui Moo, portrayed by Mark Kwak (season 4), a North Korean cosmonaut on the Ranger.

Introduced in season one

 * Neil Armstrong, portrayed by Jeff Branson (season 1), the commander of Apollo 11. He became the second man on the Moon, following soviet cosmonaut Alexei Leonov.
 * Paul Santoro, portrayed by Deniz Akdeniz (season 1), a journalist who writes an article about NASA missing the opportunity to let Ed Baldwin and Gordo Stevens land on the Moon with Apollo 10, using Ed's "The NASA doesn't have guts anymore" quote.
 * Winston Blake, portrayed by Brandon Bales (season 1), a CIA agent who met with NASA to evaluate how the Soviets managed to land on the Moon first.
 * Pete Conrad, portrayed by Steven Pritchard (season 1), the Commander of Apollo 12.
 * Graciana Rosales, portrayed by Vanessa Lyon (season 1), Aleida's mother. She died in 1969 shortly after the Soviet Moon landing. Her husband Octavio then moved to Houston with Aleida to fulfill her wish that her daughter can work for NASA to satisfy her interest in space.
 * Charles Sandman, portrayed by Saul Rubinek (season 1), an American Republican Party politician.
 * Admiral Scott Uken, portrayed by David Andrews (season 1), a US Air Force Admiral and former superior of Ed Baldwin.
 * Fred Talmadge, portrayed by Nick Wechsler (season 1), the Command Module Pilot of Apollo 10.
 * Anastasia Belikova, portrayed by Rita Khrabrovitsky (season 1), a cosmonaut who became the first woman on the Moon.
 * Ginger, portrayed by Jessica Amlee (season 1), a one-night-stand affair of Gordo Stevens.
 * Patty Doyle, portrayed by Cass Buggé (season 1), a former Mercury 13 pilot. She became an astronaut candidate for NASA as one of "Nixon's Women", but died when her training module crashed.
 * Shorty Powers, portrayed by Brian Stepanek (season 1), an American public affairs officer working for NASA.
 * Ray Schumer, portrayed by Benjamin Seay (season 1), a NASA engineer who presented the idea of hidden ice in the lunar craters, which led to NASA choosing the Shackleton Crater as location for Jamestown Moon Base.
 * Janice, portrayed by Devin McCarthy (season 1), an astronaut candidate for NASA as one of "Nixon's Women", but wasn't selected for the final program.
 * Megan Shearin, portrayed by Kate Rodman (season 1), an astronaut candidate for NASA as one of "Nixon's Women", but wasn't selected for the final program.
 * Barbara Taylor, portrayed by Leia Hurst (season 1), an astronaut candidate for NASA as one of "Nixon's Women", but wasn't selected for the final program.
 * John Glenn, portrayed by Matt Battaglia (season 1), one of the Mercury Seven astronauts, who was the first American astronaut in Earth orbit.
 * Dr. Chase, portrayed by Korey Simeone (season 1), the flight surgeon for Apollo 15.
 * Scott Kraus, portrayed by Martin Grey (season 1), a NASA engineer who was killed in the explosion of Apollo 23 alongside Gene Kranz.
 * Mike Russell, portrayed by Michael James Bell (season 1), the principal of Shane Baldwin's and Danny Stevens' school.
 * Harrison Liu, portrayed by Stephen Oyoung (season 1), an astronaut and member of the Apollo 24 crew. He died during the accidental S-IVB ignition.
 * Dr. Robert Marsten, portrayed by John Rubinstein (season 1), Gordo's psychiatrist.
 * Barry Newsome, portrayed by David Gautreaux (season 1), a talkshow host who interviewed the Apollo 24 crew.
 * Dr. David Josephson, portrayed by Scott Alan Smith (season 1), a surgeon at a Houston hospital who treated Shane Baldwin after his accident.
 * Grush, portrayed by Brian Johnson (season 1), an astronaut and back up for Apollo 24.
 * Pendle, portrayed by Jeff Denton (seasons 1–2), an astronaut and back up for Apollo 24.
 * Jerry Biddle, portrayed by Kevin Glikmann (season 1), a reporter for the Houston Sentinel who attempted to interview Karen Baldwin after Shane's accident.
 * Dr. Weddle, portrayed by Jan Munroe (season 1), a NASA neurologist who Karen Baldwin asked for a second opinion on Shane's health status.
 * Mikhail Mikhailovich Vasiliev, portrayed by Mark Ivanir (season 1), a Soviet cosmonaut who was held as a prisoner on Jamestown Moon Base by Ed Baldwin in 1974 and hid a listening device, which wasn't discovered by NASA until 1983.
 * Dennis Lambert, portrayed by Charlie Hofheimer (season 1), an astronaut and member of the Apollo 25 crew.
 * Cecilia Liu, portrayed by Aria Song (season 1), the wife of astronaut Harrison Liu.
 * Penny Chen, portrayed by Carin Chea (season 1), a flight controller for Apollo 24.
 * Carl Reid, portrayed by Theo Iyer (season 1), a flight controller for Apollo 24 and 25.
 * Sam, portrayed by Brian McGrath (season 1), a NASA engineer and flight controller for Apollo 24.

Introduced in season two

 * Wubbo Ockels, portrayed by Bjørn Alexander (season 2), an astronaut stationed on Jamestown. He left NASA following injuries sustained during a solar storm.
 * Carl Cartwright, portrayed by Brad Beyer (season 2), an astronaut stationed on Jamestown.
 * Doreen Campbell, portrayed by Penny O'Brien (season 2), an Irish scientist and astronaut stationed on Skylab, the first space station in Earth's orbit. In 1983, she detected a coronal mass ejection and warned the astronauts on the Moon about the impending lethal doses of deadly solar radiation.
 * Garrett Reisman portrayed by Garrett Reisman (season 2), a shuttle pilot. Reisman also served as a technical consultant on the show and was partially involved in the development after he and showrunner Ron Moore had discussed the possibility of a timeline in which the Soviet Union landed people on the Moon before the US.
 * Peter, portrayed by Justice Leak (season 2), Larry Wilson's lover in 1983.
 * Davey Kowalski, portrayed by Alexander Neher (seasons 2–3), Aleida's boyfriend, who was a bad influence on her. He was an oil worker and protested against NASA in the 90's because the mining of Helium-3 from the lunar surface threatened the oil economy.
 * Rae Poole, portrayed by Yaani King Mondschein (season 2), Danielle's sister-in-law.
 * Coral Hiscoe, portrayed by Carolyn Crotty (season 2), an engineer at NASA in 1983, responsible for the astronaut's spacesuits.
 * Leland Davis, portrayed by Andrew Gonzalez (season 2), an engineer at NASA in 1983, responsible for the astronaut's spacesuits.
 * Doug Price, portrayed by Chris L. McKenna (season 2), an astronaut stationed on Jamestown.
 * Elise, portrayed by Mele Ihara (season 2), Pam's new girlfriend in the 80's.
 * Stepan Petrovich Alexseev, portrayed by Nikola Djuricko (season 2), a cosmonaut and the Soviet commander of the Apollo–Soyuz mission.
 * Radislav Semenovich Orlov, portrayed by Alexander Babara (season 2), a cosmonaut on the Apollo–Soyuz mission.
 * Sergei Korolev, portrayed by Endre Hules (season 2), the head aerospace engineer of the Soviet Space Program who helped get the Soviet Union to the Moon before the United States. He later also worked on the joint Apollo–Soyuz mission. According to Ronald D. Moore, the creator of the show, the divergence point of the alternate timeline was that Korolev did not die during a surgery in 1966. His survival and further works led to the Soviets landing on the moon first.
 * William Waverly, portrayed by Bruce Weitz (season 2), Ellen's father.
 * Nguyen Linh, portrayed by Lily Huynh (season 2), Kelly's biological sister.
 * Dr. Mitchell, portrayed by Wendy Schenker (season 2), an ophthalmologist who examined Molly Cobb for the sight disorder she experienced after her return from the Moon.
 * Nguyen Van Le, portrayed by Long Nguyen (season 2), Kelly's biological father.
 * Lee Atwater, portrayed by Dustin Seavey (season 2), an American political consultant and strategist for the Republican Party who advised Ellen Wilson, which started her political career.
 * Colonel Viktor Tsukanov, portrayed by Eugene Alper (season 2), a cosmonaut stationed on the Soviet Moon Base.
 * Liz Phang, portrayed by Jinny Chung (season 2), an engineer at NASA in 1983, responsible for the astronaut's spacesuits.
 * Natalie Bishop, portrayed by Julie Brett (season 2), an astronaut stationed on Jamestown.
 * Cameron Wolfgeher, portrayed by Timothy Ware-Hill (season 2), the military CAPCOM for Pathfinder.
 * Jonathan Gatos, portrayed by Joe Sobalo Jr. (season 2), an astronaut stationed on Jamestown.

Introduced in season three

 * Yvonne, portrayed by Ashley Jones (season 3), Ed's second wife in the 1990s. They split up following the Polaris disaster.
 * Commander Rich LaPorte, portrayed by Derek Webster (season 3), the commander of the Polaris space hotel.
 * Joaquin Asencio, portrayed by Andres Londono (season 3), a controller and technician working aboard the Polaris space hotel who was killed during the disaster.
 * General Jeanette Masters, portrayed by Fran de Leon (season 3), military liaison to NASA.
 * Pastor Dirkson, portrayed by Thomas Crawford (season 3), a pastor, who officiated the wedding of Danny and Amber Stevens on board the Polaris space hotel.
 * Scotty Wilson, portrayed by Milo Cragnotti (season 3), Ellen's and Larry's son.
 * Peter Strauss, portrayed by Jonny Coyne (season 3), a KGB agent who blackmailed Margo Madison with photos of her affair with Sergei Nikulov.
 * Clarke Halladay, portrayed by Tony Curran (season 3), the pilot of Sojourner–1, killed during the collision with Mars–94.
 * Sylvie Kaplan, portrayed by Heidi Sulzman (season 3), an astronaut and crew member of Sojourner–1, killed during the collision with Mars–94.
 * Elizabeth "Zizzo" Glover, portrayed by Debbie Pollack (season 3), a biologist and member of the Phoenix crew.
 * Anne Baranov, portrayed by Jessica Galinas (season 3), Rolan's wife.
 * Peter Baranov, portrayed by Leo Marz (season 3), Rolan's and Anne's son.
 * Jonathan Adams, portrayed by Christopher Ellay (season 3), a NASA engineer in 1994.
 * Jean Williamson, portrayed by Diane Dehn (season 3), the public relations officer of the Johnson Space Center.
 * Mary Meineke, portrayed by Bonnie Bailey-Reed (season 3), a NASA receptionist in 1994.
 * Jeremy Zielke, portrayed by John Forest (season 3), an employee at the White House, who has an affair with Larry Wilson.
 * Elliott Lewis, portrayed by Michael McMillian (season 3), an old college friend of Jeremy Zielke who leaked his affair with Larry.
 * Karl Rove, portrayed by Joseph Beck (season 3), a political consultant who works for President Ellen Wilson.
 * Willie Baron, portrayed by Patrick Labyorteaux (season 3), an American Democratic congressman.
 * Avery Stevens, portrayed by Delaney Claire Evans (season 3), Parker Reese Evans (season 3) and Ellie Grace Pomeroy (season 4), Danny's and Amber's daughter.
 * Pavel Zaitzev, portrayed by Vlad Pavlov (season 3), an engineer of Roscosmos.
 * Victoria Rodriguez, portrayed by Michelle C. Bonilla (season 3), an FBI Special Agent, who investigated against Margo Madison due to her connection to Sergei Nikulov.
 * Arlene Spielman, portrayed by Kristin Carey (seasons 3–4), a board member of Helios Aerospace from the mid 90s until 2003, when she was fired by Dev Ayesa.
 * Park Chol, portrayed by Jason Her (season 3), a North Korean cosmonaut, who died during the landing on the Mars.

Introduced in season four

 * Tom Parker, portrayed by Mac Brandt (season 4), an astronaut who is killed during the Kronos mission.
 * Tom Gamon, portrayed by Dave Theune (season 4), an HR employee at Helios Aerospace who hired Miles Dale.
 * Colonel George Peters, portrayed by Jay Paulson (season 4), the commander of Happy Valley in 2003, who is relieved of his duties following the failed Kronos mission.
 * Kirill Semenov, portrayed by Gediminas Adomaitis (season 4), a Roscosmos official.
 * Fyodor Korzhenko, portrayed by Dimitar Bakalov (season 4), the new president of the Soviet Union, who overthrew Mikhail Gorbachev in 2003.
 * Shaun Arlee, portrayed by Brandon Ford Green (season 4), a space worker.
 * Owen Stanwood, portrayed by Alex Parkinson (season 4), an astronaut.
 * Lieutenant Stepan Gura, portrayed by Konstantin Lavysh (season 4), a Soviet police officer who interrogated Margo Madison before being killed the coup d'état that overthrew Mikhail Gorbachev.
 * Colonel Vidor Kolikoff, portrayed by Nikolai Tsankov (season 4), a Soviet military officer who participated in the coup d'état that overthrew Mikhail Gorbachev in support of Fyodor Korzhenko.
 * Vasily Galkin, portrayed by Eduard Osipov (season 4), a Soviet cosmonaut on Happy Valley.
 * Gwan Jin Tao, portrayed by Daniel Juhn (season 4), a North Korean cosmonaut on Happy Valley.
 * Katherine Hobson, portrayed by Kathe Mazur (season 4), Eli Hobson's wife.
 * Leia Ascott, portrayed by Rachael Thompson (season 4), a CIA Agent assigned to NASA after the incident involving Svetlana Zakharova and Vasily Galkin.
 * Lev Babanin, portrayed by Alexander Terentyev (season 4), a high-ranking Roscosmos official.
 * Mike Shaw, portrayed by Luke Barnett (season 4), a Helios worker on Happy Valley.
 * Yevgeniy, portrayed by Nicholas Kolev (season 4), a high-ranking Soviet cosmonaut on Happy Valley.
 * Malaika Ayesa, portrayed by Valeri Ross (season 4), Dev Ayesa's mother.
 * Brandt Darby, portrayed by Dustin Ingram (season 4), a Helios employee working in government relations.
 * Ron Klain, portrayed by Jon Levine (season 4), a political consultant working for President Al Gore in 2003.
 * Dimitri Egotov, portrayed by Sacha Seberg (season 4), a Roscosmos engineer on Happy Valley.
 * Natalia Morioka, portrayed by Madara Jayasena (season 4), a NASA astronomer at the Goddard Space Flight Center who discovered the Goldilocks asteroid.
 * Kate Marsteller, portrayed by Libby Baker (season 4), a NASA astronomer who presented the discovery of the Goldilocks asteroid to NASA administrator Eli Hobson.
 * Henry Keck, portrayed by Gene Silvers (season 4), a space worker.
 * Kenji Okumura, portrayed by Yuji Hasegawa (season 4), the JAXA delegate at the M-7 summit in 2003.
 * Kapalna Naran, portrayed by Deepti Gupta (season 4), the ISRO delegate at the M-7 summit in 2003.
 * Robert Burks, portrayed by David Bowe (season 4), the CIA Deputy Director in 2003.
 * Nick Jennings, portrayed by Chris Jaymes (season 4), a NASA engineer on Happy Valley who died in an explosion while trying to bypass the Helios worker strike.
 * Muriel Bezukhov, portrayed by Heather Lee (season 4), Sergei Nikulov's wife in 2003.
 * Nam Moon Yeong, portrayed by Chen Chen Julian (season 4), Lee's wife.
 * Courtney Johnson, portrayed by April Mae Davis (season 4), Isaiah's wife.

Upcoming characters

 * Celia Boyd, portrayed by Mireille Enos (season 5), a member of the Peacekeeper Security Force on Mars.

Presidents of the United States
Due to the alternate history nature of the show, it features a different timeline of presidents:
 * John F. Kennedy (1961–1963)
 * Lyndon B. Johnson (1963–1969)
 * Richard Nixon (1969–1973), losing the 1972 United States presidential election against Ted Kennedy. After cosmonaut Anastasia Belikova became the first woman on the Moon, he demanded that NASA also starts a program featuring women as astronauts who then became known as "Nixon's Women". Out of 20 "Astronaut Candidates", five were elected, namely Tracy Stevens, who was the wife of Apollo 15's Gordo Stevens, two of the last of Mercury 13 named Molly Cobb and Patty Doyle, a black woman named Danielle Poole, who worked as a NASA computer and Ellen Waverly.
 * Ted Kennedy (1973–1977), winning the 1972 election against Nixon, but then losing the 1976 election against Ronald Reagan.
 * Ronald Reagan (1977–1985), winning the 1976 election against Kennedy and the 1980 election against Senator Robert Money.
 * Gary Hart (1985–1993), winning the 1984 election against Richard Schweiker and the 1988 election against Pat Robertson.
 * Ellen Wilson (1993–2001), winning the 1992 election against Bill Clinton and the 1996 election against Jerry Brown.
 * Al Gore (2001–), winning the 2000 election against George H. W. Bush.