Amy, Rory and River are summoned to the Utah desert, where they witness the Doctor's murder at the hands of an astronaut who rises from the waters of Lake Silencio. The Doctor's final message directs them to travel to 1969 with a slightly younger version of himself. Materialising in the White House, they meet President Richard Nixon and ex-FBI agent Canton Delaware III. Nixon wants Canton to investigate the phone calls he receives every night from a mysterious child, warning of alien invasion. But the aliens, immune to capture by human memory, arrived long ago...

Since the revival of Doctor Who in 2005, each season had followed the same basic structure, consisting of seven single-episode stories and three two-part adventures, one of which formed the season finale. Between Seasons Twenty-Seven and Thirty-One, there had been only minor deviations from this scheme, such as Utopia and The Sound Of Drums / Last Of The Time Lords arguably forming a three-part conclusion to Season Twenty-Nine. For Season Thirty-Two, however, executive producer Steven Moffat decided that it was time to change things up. In particular, he wanted to captivate audiences with a spectacular two-part story not at the end of the year, but at its very start.

Meanwhile, discussions were under way with BBC America concerning the possibility of the cable channel co-producing episodes to be filmed in the United States. Doctor Who was becoming increasingly popular overseas, with Season Thirty-One breaking BBC America viewing records. The production team was keen to capitalise on this success, and they felt that a story set in the USA would help broaden the programme's appeal, while rewarding its many American fans. Although the notion of a Stateside location shoot had been mooted as far back as 1981 -- when Lesley Elizabeth Thomas was commissioned to write an ultimately-unused story called “Way Down Yonder” -- the closest that Doctor Who had achieved to date was three days of plate shots in New York City for Season Twenty-Nine's Daleks In Manhattan / Evolution Of The Daleks.

Steven Moffat started considering iconic American times and places which the Doctor could visit

As Moffat began contemplating ideas for the Season Thirty-Two premiere, an agreement was reached with BBC America. Consequently, he started considering iconic American times and places which the Doctor could visit. Moffat became keen to incorporate NASA: the National Aeronautics and Space Administration, established in 1958 during the early days of the “space race” with the Soviet Union. In particular, he decided to set his narrative around the original Moon landing on July 21st, 1969, when Apollo 11 astronauts Neil Armstrong and Buzz Aldrin touched down on the lunar surface. Having been a big fan of Aaron Sorkin's political drama The West Wing, broadcast from 1999 to 2006, Moffat also wanted to feature sequences in the Oval Office at the White House. This invited the inclusion of President Richard Nixon, who had been inaugurated earlier in 1969. Florida, the home of NASA's Launch Operations Center, and Mount Rushmore in South Dakota were also considered as potential locations. However, it was eventually decided that Utah and Arizona were the best choices to achieve a setting which would be distinctly different from anything that could be recorded in the United Kingdom.

Moffat began writing his scripts around May 2010, and completed first drafts towards the end of August. As the hook which would grab viewers in the premiere episode, Moffat revisited ideas he had considered for Season Thirty-One. For a time in early 2009, David Tennant had contemplated remaining on Doctor Who to play the Tenth Doctor for an additional year. This forced Moffat to consider how the Season Thirty-One story arc could be amended to include an already-established Doctor, as opposed to a brand-new incarnation. He had decided that the opening episode would depict the Tenth Doctor on the verge of regenerating, with the rest of the season then chronicling the events which led up to that moment. For Season Thirty-Two, Moffat amended this idea to feature the Doctor's apparent murder, rather than his regeneration. Amy and Rory would then have to deal with their foreknowledge of the Doctor's fate, with the true explanation for these events finally revealed in the season finale.

A key element was the introduction of a new monster called the Silents, explicitly linked to the enigmatic Silence which had been mentioned in several episodes during Season Thirty-One. Moffat hoped that these creatures would become as popular as his earlier creations, the Weeping Angels, and he was again inspired by a simple, everyday phenomenon: the impermanence and unreliability of memory. Visually, the Silents were based upon the Norwegian artist Edvard Munch's most famous work, the 1893 painting Skrik (that is, The Scream). Another influence was the common description in modern folklore of extraterrestrials often called “Greys”, first popularised in the Sixties. This tied in with the inclusion of material set at Area 51, a United States Air Force establishment at Groom Lake in Nevada which had been in operation since 1955. Widely believed to be the site of cutting-edge research in weapons and aircraft, the highly-classified nature of Area 51 had prompted the conspiracy theory that it also housed alien technology, and even captured extraterrestrials.

Episode 2 incorporated a running gag in which the Doctor insisted on keeping his beard

The second episode initially incorporated two running gags, in which the Doctor insisted on keeping his beard, and River refused to remove his handcuffs. They eventually dovetailed when River advanced upon the restrained Doctor with a shaving razor in hand. The addled Dr Renfrew was named for RM Renfield, the madman who was in thrall to the eponymous vampire of Bram Stoker's 1897 novel Dracula. The titles for the two scripts were originally “The Year Of The Moon” and “Look Behind You”, but Moffat began to ponder alternatives in October after they were panned by his young son. A few days later, Episode One had become The Impossible Astronaut, while Episode Two would eventually be called Day Of The Moon.

The two-part adventure was made as the second block of the Season Thirty-Two production schedule. Assigned to direct was Toby Haynes, who had just completed A Christmas Carol, the 2010 Christmas special; this would be his final work on Doctor Who. Cast as Canton Delaware III was Mark Sheppard, who had appeared in shows like The X-Files, Firefly, 24 and the remake of Battlestar Galactica. His involvement with Doctor Who was slotted into a gap in his recording schedule for the dark fantasy Supernatural, in which he had a recurring role as the demon Crowley. It was hoped that Sheppard's association with the villainous character would make viewers suspicious of Canton's motives. Originally, it was thought that Sheppard would also portray the elderly Canton in the sequence at Lake Silencio. However, he encouraged the production team to instead cast his father, William Morgan Sheppard, whose many credits included episodes of Max Headroom, Star Trek: The Next Generation, seaQuest DSV and Babylon 5. The pair had likewise played two versions of the same character in a 2009 episode of the procedural drama NCIS.

Filming for The Impossible Astronaut / Day Of The Moon began on October 13th, three days after BBC America formally announced the funding arrangement for the location shoot in the USA. Work began in Wales, with Tredegar House in Newport providing Matilda's chamber. As with the portraits seen in A Christmas Carol, the painting of the Doctor was created by Katie Pickwoad, the daughter of production designer Michael Pickwoad. Later on the 13th, a dwelling on Avondale Crescent in Cardiff was Amy and Rory's new home. On October 14th and 15th, TARDIS scenes were taped at Doctor Who's regular studio facilities in Upper Boat. Haynes also ventured just outside the studio during the latter day to capture the green screen shot which introduced Apollo 11. Semi-regular Alex Kingston rejoined the Doctor Who team at Upper Boat to play River for the first time since the February recording of The Pandorica Opens / The Big Bang. To aid her performance, Moffat gave Kingston complete details of the season's arc -- including the mystery of the Doctor's apparent death and River's true parentage -- while the rest of the cast was kept in the dark to varying degrees.

After the weekend, a busy October 18th in Cardiff started at Le Monde, a bar and grill which was dressed as the Washington pub. White House corridor sequences were then filmed at the Glamorgan Building, followed by River's apparent suicide dive at Cadogan House. On the 19th, the Utah restaurant was actually Eddie's Diner in Cardiff. From the 20th to the 22nd, Haynes' team was back at Upper Boat, with the first two days spent on the standing TARDIS set, and the last on a redressed version of the time capsule set originally constructed for Season Thirty-One's The Lodger. It was back to Cardiff on October 23rd, when the Millennium Stadium hosted scenes at Stormcage, alongside the FBI's pursuit of River up a staircase.

The production stood down on Sunday the 24th and Monday the 25th. More Cardiff filming took place on October 26th, starting at the Coal Exchange for the scene in the White House ladies' washroom. That evening, the girl's regeneration in a New York alley was taped at Crockherbtown Lane; at one stage, this sequence had been set in Chicago instead of the Big Apple. The venue for the rest of the week -- from October 27th to 30th -- was Troy House in Mitchel Troy. Originally built in the seventeenth century for the Duke of Beaufort, the structure had subsequently been a convent and a school for juvenile delinquents. However, its current dilapidated state made it an ideal location for Graystark Hall.

Following a day off on Hallowe'en, Haynes' team spent November 1st to 4th in Pontypool, at the Johnsey Estates in the Mamhilad Park Industrial Estate. It principally posed as the warehouse at the corner of Jefferson Street, Adams Street and Hamilton Avenue. The last day also dealt with the POW camp material from the beginning of the story, plus Canton chasing River through the office building at the start of Day Of The Moon. Next, sequences in Area 51 were filmed at MOD St Athan on November 5th, before another break on Saturday the 6th.

Work on November 7th began at Cardiff University for scenes at NASA. The latter part of the day -- and, indeed, the rest of the week -- was then spent back at Upper Boat, initially for sequences in the Silents' time capsule. From the 8th to the 11th, Haynes focussed primarily on the Oval Office. Also on his itinerary were scenes in the tunnels on the 8th, the Doctor's performance in the 1939 Stan Laurel and Oliver Hardy film The Flying Deuces on the 9th, and material in the Doctor's cell and the Apollo 11 capsule on the 11th. Various inserts and effects shots were also completed throughout, and indeed were the sole item of business on the 12th.

Locations in Utah were chosen for their unique geography, offering impressive sandstone buttes

With principal photography in the United Kingdom now complete, minimal cast and crew flew across the Atlantic for a three-day shoot. Apart from Haynes, the only BBC crewmembers present were producer Marcus Wilson, director of photography Stephan Pehrsson, and brand manager Edward Russell; regulations required that other duties be assigned to an American crew. Filming in south-eastern Utah took place on November 17th, starting with Amy fleeing from Canton through the Valley of the Gods. Next, the reunion of the Doctor, Amy, Rory and River by the side of the highway took place in Monument Valley. As scripted, Amy and Rory were dropped off by a truck, but Haynes replaced it with a yellow school bus, which he felt was more distinctly American. Both sites were popular locations for movies and television programmes, and were chosen for their unique geography, offering impressive sandstone buttes and other formations. In addition to the appropriate state authorities, permission to record in Monument Valley was also granted by the Navajo Nation.

The Doctor Who team then travelled across Utah's southern border, to the small city of Page, Arizona. The chief venue on November 18th was Lake Powell, which posed as Lake Silencio; the artificial reservoir was created in 1963 when the construction of a dam allowed the Colorado River to flood Glen Canyon. While recording the Doctor's apparent demise, Kingston drew on her knowledge of the season's secrets and decided that River would react in a particularly comforting way towards Amy. Karen Gillan, however, was unaware that their characters would soon be revealed as mother and daughter, and so she was quietly baffled by Kingston's demeanour. More filming at Lake Powell took place on the 19th, after which Canton cornered Rory at the nearby Glen Canyon Dam. This sequence had originally been written as taking place on the San Francisco docks.

Back in the United Kingdom, only one shot remained to be completed for The Impossible Astronaut / Day Of The Moon: the appearance of the “Eye Patch Lady” in the second episode. It was taped alongside several similar inserts on January 27th, 2011 at the premises of Fillcare, a Pontyclun-based manufacturer of personal care products.

On March 25th, a special prequel to The Impossible Astronaut was released

On March 25th, a special prequel to The Impossible Astronaut was released as part of an early wave of publicity for the new season. Written by Moffat, it ran to one hundred and fifteen seconds, and featured President Nixon receiving a phone call from the mysterious girl -- unaware that he was being observed by a Silent. It had been recorded by Haynes on November 11th, using the Oval Office set at Upper Boat. This piece was a return, of sorts, to a concept which had run through Season Twenty-Eight in 2006, when every episode was preceded by a brief TARDISode. The social media strategy for Season Thirty-Two would reprise the notion, albeit only for select adventures.

Season Thirty-Two was scheduled to premiere on April 23rd; this was Easter Saturday, a date now chosen for the debut of four out of the six seasons which had been broadcast since 2005. Sadly, the excitement surrounding the programme's return to the airwaves was tempered on April 19th when it was learned that Elisabeth Sladen -- who had played the Doctor's enduringly popular companion Sarah Jane Smith, and who still starred in CBBC's The Sarah Jane Adventures -- had passed away after a battle with cancer. It was quickly decided that The Impossible Astronaut would open with a title card which dedicated the episode to Sladen's memory. Both parts of the serial aired in a 6.00pm time slot, after the new game show Don't Scare The Hare and before the second season of the reality competition So You Think You Can Dance.

• Doctor Who Magazine Special Edition #29, 14th December 2011, “The Impossible Astronaut / Day Of The Moon” by Andrew Pixley, Panini Publishing Ltd.
• Doctor Who: The Complete History #66, 2017, “Story 214: The Impossible Astronaut / Day Of The Moon”, edited by John Ainsworth, Hachette Partworks Ltd.