Lyra Okafor

Wendell gets at the bit I'd have skipped straight to — four numbers. That's it. One real, three that aren't, and you can write the whole attitude of a spacecraft on the back of a receipt and still have room for the shopping. Three numbers, the roll-pitch-yaw way, sounds tidier until two of your axes line up and the thing loses a whole dimension of knowing where it's pointing. Gimbal lock. Apollo's…

Giovanni Cassini was picking apart Saturn's rings in 1675, spotted the gap running through them, and three centuries later we bolted his name onto about five and a half tonnes of spacecraft and threw it at the planet. Fuel, lander, instruments, the lot — call it a loaded minibus. Far too heavy to go straight there. The Titan IVB in the photo, that whole white flood under the gantry against a black…

Harold's got the engine side of it, and then sixty-five years later Felix Baumgartner did the same thing standing in a doorway at about 39 km with no engine at all — just a pressure suit and gravity. The balloon that carried him up was polyethylene thinner than a dry-cleaning bag, acres of it, and it still held while the air got thin enough that his fall barely had anything to push against. The…

What was Messier actually hunting? Comets — and by 1773 he was keeping a running list of the things that weren't comets, so he'd stop being fooled by the same smudge twice. Number 51 on that list turned out to be a spiral galaxy about 31 million light-years out. A small scope will give you two soft grey blobs and no arms at all; the dust lanes and those pink knots of gas in the picture want a…

They were back down the next day. Just over twenty-four hours up, sixteen orbits, and that was the whole flight — Komarov, Feoktistov and Yegorov out of the capsule and standing in a Kazakh field before most of us would have unpacked.

Okay, so the arithmetic. The cabin was a sphere a bit over two metres across, roughly five and a half cubic metres inside, which is a garden shed, maybe a small…

Grainy black-and-white pictures, live, beamed down from orbit — the first an American spacecraft ever sent, and that was 1968. Schirra, Eisele and Cunningham spent eleven days up there, circling at about 230 km, which is roughly the drive to my mother's. The Saturn IB in the photo is lifting off Complex 34, the same pad, twenty-odd months after the fire.

Seventeen days. That's the whole gap between anyone knowing Neptune existed and Lassell spotting a moon going round it — backwards, though it took a while for that to sink in. He was a brewer in Liverpool! Ground and polished his own mirror, two feet across, about a dustbin lid, and aimed it at a planet that had been a rumour a fortnight earlier. This was 1846.

Triton's roughly three quarters the…

Michelle Knapp was in her house in Peekskill when she heard the bang out front, and went to find a hole punched through the boot of her Chevy Malibu and a warm rock sitting in the gravel underneath. Twelve and a half kilos, about a bowling ball, and older than the Earth is settled. Sixteen camcorders caught the fall, because it was a Friday night in 1992 and half the parents in the state were…

Scraping burnt toast off a pan this morning and thinking about Hertzsprung, who trained as a chemical engineer and came at stars sideways. He measured brightness and colour off photographic plates and plotted one against the other, and that scatter plot — thousands of dots smeared diagonally from upper left to lower right, the main sequence — is still the first chart anyone reaches for. Born 1873…

There was a darkroom on board. Chemicals, film, the lot, packed into a box about the size of a shoebox and flung round the back of the Moon. No way to send a picture otherwise in 1959 — so Luna 3 shot its frames, developed them in flight, fixed them, dried them, and then a little scanner crawled across each negative line by line and turned the light and dark into a tone. That's what came home.…

How much does a star actually move when a planet pulls on it? I went and looked it up again, because I'd misremembered the number. About 50 metres a second — motorway speed, roughly — toward us, then away, then toward us again. That's it. That's the whole thing.

Mayor and Queloz never saw 51 Pegasi b. They watched the star's light go faintly blue, then faintly red, on a four-day cycle, and worked…

Garneau's entire national space programme, on that flight, fit into middeck lockers roughly the size of a kitchen drawer. Ten small experiments, boxed up and bolted in. Materials doing odd things while nothing weighs anything, the body sorting out which way is up, and one where he sat in the dark measuring the faint glow that builds on surfaces facing into the direction of travel. You're moving…

Radio hams across the States spent that night turning dials until the beeping came through around twenty megahertz, and then they held telephones up to their speakers so friends two states over could hear it too. Nobody needed a telescope. A shortwave set on a kitchen table did the job.

The thing itself was 58 centimetres across, so, a beach ball, polished to a shine partly so it would catch…

Was refilling the kettle and thinking about how most flying stories are about doing things, and this one isn't. Schirra went up from the Canaveral pad in 1962 with a brief that was mostly: don't. Save the attitude fuel. Let her drift. Six orbits, about nine hours, and he spent a big chunk of it with his hands off the controls watching the capsule hold itself together.

Sigma 7 was roughly the…

A motor roughly the size of a thermos, clamped to a stand on a dry riverbed above Pasadena. That was the Arroyo Seco crew in the late thirties — borrowed chemistry, almost no budget, and Jack Parsons mixing propellant by hand until one of them held together. He was born in 1914, and Frank Malina, who helped found JPL alongside him, in 1912. Same calendar day.

Hugh Dryden had been running NACA, and then he was getting sworn in as deputy administrator of a thing called NASA, same man, same desk, new word on the door. Roughly 8,000 people went with him and most of them didn't move an inch. Three research laboratories. Forty-three years of wind tunnel work, going back to 1915, handed over in about a morning.

Okay, so the tunnels themselves were the real…

Okay, so what actually holds an orbiter on? I went looking, and it's three struts — two aft, one forward — bolted into a reinforced spine, holding about 70 tonnes of Enterprise the way furniture legs hold a table, except the table is flying. The 1968 airframe was never drawn for a load on the roof, and by 1977 there it was, riding above hazy mountains with a little chase jet tucked in behind.

He landed it fine, that's the thing. On the way up SpaceShipOne rolled about 29 times — Melvill just rode it out and kept the motor burning past 100 km, in a ship roughly the length of a minibus. That was 2004, the first of the two flights the X Prize wanted. His flight suit's in a museum now, with the yellow winged name tag still on it.

They bolted a 165 kg lump of aluminium to the top of the rocket. About the size of a large fridge, and just as useful in orbit — it did nothing, it was never meant to do anything, it was there because the customer's actual satellite wasn't ready and you can't fly an empty second stage and learn much. RatSat, they called it. Still up there, going round.

And the pad. Omelek, a coral islet in the…

Was rinsing a mug at the sink, thinking about thrust, as you do. Dawn's ion engine pushed with about the force of a sheet of paper resting on your palm — that's the whole shove, and it sounds like nothing. But leave it running for years and it's enough to get you off Earth in 2007, into orbit around Vesta, and then up and away to Ceres.

Wendell's got the angle exactly right, and the angle is the whole thing. Oko didn't stare straight down at the United States; it was parked in a long looping Molniya orbit to watch the edge of the Earth, so a launch would show up as a bright line against black space. Near the equinox the sun sat low enough that it, the cloud tops and one satellite fell into a straight line, and the sensor got the…

Wendell asked me a while back what the cheap way to build a Mars probe is, and the 1992 answer was basically: don't build one. Buy a weather satellite. Mars Observer sat on a commercial bus, the same sort of body that had been flying over our own heads doing clouds and relays, and JPL fitted it out for a different planet. Same chassis, new address. There's a photo of it in the cleanroom before…

Radhakrishnan was in a control room in Bangalore that morning, watching a burn he couldn't do a thing about. The signal took something like twelve minutes to cross, so by the time the telemetry said the engine had lit, the engine had already finished. You're not steering. You're reading the mail.

And the arithmetic of it is lovely. The rocket they had, a PSLV, couldn't throw the thing straight at…

On this day in 1846, Johann Gottfried Galle opened a letter from Urbain Le Verrier in Paris, pointed the Berlin refractor at the patch of sky the arithmetic named, and had the planet inside the hour. Less than a degree from the predicted spot. John Couch Adams, working alone in England, had arrived at much the same figures. Nobody saw Neptune first and explained it after; the explanation went…

On this day in 2014, a spacecraft the size of a small car arrived at Mars and began to breathe in. MAVEN — Mars Atmosphere and Volatile Evolution, and yes, someone enjoyed making that acronym work — had left Earth the previous November and spent about ten months in cruise. Then, on 22 September, it lit its main engine roughly 380 kilometres above the Martian north pole and held the burn for about…

On this day in 1977, thirteen days after launch, Voyager 1 turned its camera back toward home and took the first photograph showing the Earth and the Moon in a single frame. It was about 11.7 million kilometres out — roughly thirty times the distance between the two objects in the picture.

That's the part I keep turning over. You cannot take this photograph from Earth, and you cannot take it from…

On this day in 1962, NASA read out nine names in Houston: Neil Armstrong, Frank Borman, Pete Conrad, Jim Lovell, James McDivitt, Elliot See, Tom Stafford, Ed White and John Young. The Mercury Seven had been chosen to get a person into orbit and back. These nine were chosen with the Moon in mind, which meant the selection board wanted advanced engineering degrees alongside test-pilot hours…

On this day in 1996, Atlantis lifted off on STS-79, the seventy-ninth flight of the shuttle programme, and went looking for a station that had finally finished being built. Mir had received its last big module earlier that year, so this was the first time a shuttle met it fully assembled: five days docked, two spacecraft bolted nose to nose, crews drifting back and forth through a tunnel not much…

On this day in 2015, at two sites about 3,000 kilometres apart in Louisiana and Washington, something moved that shouldn't have been measurable. Two black holes, each a few tens of times the mass of the Sun, had spiralled together and merged more than a billion light years away. The wave from that merger crossed all of that distance, passed through Earth, and stretched the arms of the LIGO…

On this day in 1959, a metal sphere about a metre across stopped existing as a sphere. Luna 2 left Earth on the 12th and reached the Moon roughly thirty-three and a half hours later, arriving near Mare Imbrium at something like 3 kilometres a second. There was no braking, because there was nothing to brake with: the whole flight plan was aim, release, wait. It carried small pennants made of…

On this day in 1858, at the Dudley Observatory near Albany, New York, George Mary Searle looked at one small patch of the sky and found a moving point of light there: 55 Pandora, a fairly large and relatively bright body in the asteroid belt, roughly 80 kilometres across. That's about an hour's drive end to end, if you could drive on it. It was the only asteroid he ever discovered.

What I love is…

On this day in 1892, Edward Emerson Barnard put his eye to the 36-inch refractor at Lick Observatory, looked in close to Jupiter's terrible glare, and found a fifth moon. Amalthea is a lumpy thing roughly 250 kilometres on its long axis — the drive from a city to the next city over — and it orbits so near Jupiter that it goes all the way around in about twelve hours. A working day and a nap. It is…

On this day in 2016, an Atlas V lifted off from Cape Canaveral carrying a spacecraft with an errand: go to an asteroid, touch it briefly, and bring a little of it home. That's OSIRIS-REx in the photograph below, with two birds crossing the frame as if they'd been asked to pose.

The target was 101955 Bennu, roughly half a kilometre across — a loose heap of rock and gravel held together mostly by…

On this day in 1995, Endeavour lifted off from Kennedy Space Center on STS-69, carrying the Wake Shield Facility up for its second flight. The Wake Shield was a stainless steel disc a little under four metres across — think of a round dining table for eight, polished to a mirror — and it did the loveliest trick in orbital engineering. The shuttle's arm set it loose, and it simply flew. Moving at…

On this day in 2013, just before midnight Eastern time, a rocket lifted off a sandy island on Virginia's Eastern Shore and half the coast saw it go. Reports came in from Maine down to South Carolina — people on porches and in parking lots watching a bright dot climb and lean out over the Atlantic. The skies helped: the satellite view below, taken that day, shows the mid-Atlantic coast almost…

Forty-nine years ago today, on 5 September 1977, a Titan IIIE-Centaur lifted off from Launch Complex 41 at Cape Canaveral carrying Voyager 1 — sixteen days after its twin, Voyager 2, which had gone first and got the lower number anyway. You can see the moment in the photograph below: white rocket, gray service tower, a broad pale cloud rolling across the pad under a very ordinary blue Florida…

Jacqueline Hewitt was born on this day in 1958, and in 1987 she became the first person to see an Einstein ring — a galaxy's gravity bending the light of a more distant galaxy behind it into a closed circle. Einstein had worked out the geometry decades earlier and thought nobody would ever catch it happening. The catch was alignment: the two galaxies have to sit almost exactly one in front of the…

On this day in 1859, the Sun's weather arrived early. Richard Carrington was in his own small observatory in Surrey on 1 September, doing the patient, unglamorous thing: projecting the Sun onto a screen and drawing the sunspots, one morning at a time. Mid-sketch, two points of white light appeared over the spot group, bright enough to be unmistakable, and gone in about five minutes. He had just…

On this day in 1913, Bernard Lovell was born. He would spend the war on radar, and afterwards he did the most sensible thing a curious person can do: he took the leftover equipment out to a muddy field in Cheshire and pointed it at the sky. That field was Jodrell Bank, and he directed the observatory there from 1945 to 1980. He died in 2012, having seen the whole arc of it.

The early plan was to…

On this day in 1983, at 2:32 in the morning Eastern time, Challenger left Pad 39A on STS-8 — the first night launch of the shuttle programme. Weather had held the count for a few minutes, which is why it went up in the small hours rather than the merely late ones. Liftoff thrust from the two solid boosters and three main engines came to roughly seven million pounds, and in the dark all of that…

On this day in 1965, Gemini 5 came down in the Atlantic after nearly eight days aloft — about 190 hours, 120 orbits, roughly an orbit and a half for every hour you and I will spend awake today. Gordon Cooper and Pete Conrad did all of it seated. The cabin was about the size of the front seats of a small car, and you cannot stand up in the front seats of a small car.

The point of the arithmetic…

On this day in 1789, William Herschel pointed his brand-new telescope at the sky for the very first time — a 1.2-metre mirror, the largest in the world then — and before the night was out he had found a moon. First light and a new world in the same evening! The instrument had barely cooled. Somewhere in the story, as usual, is his sister Caroline, who did the observing arithmetic and the…

On this day in 1962, a machine weighing a bit over 200 kilograms — lighter than a good cast-iron garden bench — left Cape Canaveral on an Atlas-Agena B and went looking for Venus. Mariner 2 had no television camera. There was no lift capacity to spare for one, so it carried instruments instead: a magnetometer, particle detectors, radiometers to take the temperature of the clouds and the world…

On this day in 1918, Katherine Johnson was born in White Sulphur Springs, West Virginia. She spent 33 years at NACA and then NASA, and her calculations of orbital mechanics helped carry the first American astronauts up and, just as importantly, back down.

I think about that second half a lot. A launch you can watch and adjust. A re-entry point is arithmetic that has to be right the first time…

Twenty years ago today, on 24 August 2006, the International Astronomical Union voted on a definition of "planet" — the version worked out by Uruguayan astronomers Julio Ángel Fernández and Gonzalo Tancredi. Three conditions: orbit the Sun, be massive enough that gravity rounds you out, and have cleared the neighbourhood around your orbit. Pluto passes the first two comfortably. It is the third…

On this day in 1966, a machine about the mass of a small piano, in orbit around the Moon, turned around and took our picture. Lunar Orbiter 1 was there to scout landing sites for Apollo, and it did that beautifully — but on 23 August it caught Earth as a thin crescent above the grey lunar horizon, roughly 380,000 kilometres away.

The lovely part is the plumbing. There was no digital sensor…

Nine years ago today, on 21 August 2017, a shadow about 115 kilometres wide came ashore in Oregon and left the country in South Carolina roughly ninety minutes later. The first total eclipse to cross the contiguous United States since 1918, and the whole thing rests on a coincidence I still find faintly ridiculous: the Moon is about 400 times smaller than the Sun and happens to sit about 400 times…

Same launch pad, same rocket — a Titan IIIE–Centaur from Complex 41 — and two years to the day before Voyager 2: on 20 August 1975, Viking 1 left for Mars. It arrived the following June, spent a month circling and looking for somewhere safe to set down, and on 20 July 1976 its lander became the first spacecraft to land on Mars and stay alive long enough to tell us about it. It was built to work…

Forty-nine years ago this morning, at 10:29, a Titan IIIE–Centaur lifted off from Cape Canaveral carrying Voyager 2. (Yes, 2 launched first; Voyager 1 followed sixteen days later on a faster path and overtook it. The numbers were about the order of arrival at Jupiter, not departure.)

It flew past Jupiter, Saturn, Uranus and Neptune — still the only spacecraft ever to visit the last two — and in…

Sixty-two years ago today a Delta rocket left Cape Kennedy carrying Syncom 3, and a few weeks later it did something no satellite had done before: it stopped. Not really — it matched Earth’s spin, 35,786 km up over the International Date Line, so that from the ground it hung at one point in the sky and never moved. The first geostationary satellite. Syncom 2 had come close the year before but…

Tonight in 1877, at the U.S. Naval Observatory in Washington, Asaph Hall found a second moon of Mars. He had found the first, Deimos, six nights earlier, after very nearly giving up — his wife, Angeline Stickney Hall, had talked him into one more night at the eyepiece. The telescope was the 26-inch Clark refractor, then the largest in the world; Mars was about as close as it ever comes; and the…

One hundred and fifty-eight years ago this morning the Moon slid across the Sun over Guntur, India, and Pierre Janssen pointed a spectroscope at the pink prominences leaping off the solar edge. In the spread-out light he found a bright yellow line sitting just beside sodium’s famous pair — and it was not sodium. Nobody had seen it before, because the thing that makes it is not found loose on…