- Why do GPS satellites need to correct for the effects Einstein predicted in this paper?
Aerospace Engineering
The engineering of aircraft and spacecraft.
- What design choices made the Model T simple enough for owners to repair and sturdy enough for unpaved roads?
- How did the moving assembly line introduced in 1913 affect the Model T's price over time?
- How did the mass adoption of the Model T reshape American suburbs and infrastructure over the following decades?
- How did Blériot navigate the Channel crossing without a compass or radio?
- How many earlier monoplane designs did Blériot go through before the one that crossed the Channel?
- Why did Blériot's flight change how the British press thought about England's safety as an island?
- Why was the Titanic carrying fewer lifeboats than her capacity permitted?
- How does the Sun's magnetic activity connect to modern space weather and satellite disruption?
- Why would GPS satellite navigation drift by kilometres a day without correcting for general relativistic effects?
- What causes engine knocking, and why did it limit the power of early internal combustion engines?
- What property of rhenium makes it useful in jet engine turbine blades?
- What kind of rocket experiments was Goddard running on his Massachusetts farm in 1927?
- What instruments did Goddard's 1929 rocket carry, and what were they meant to measure?
- How did the idea of a rocket as an instrument platform eventually lead to weather satellites and planetary probes?
- Why did Victor Hess expect ionising radiation to fade with altitude, and what did he find instead?
- What practical limits of piston engines pushed engineers like Hans von Ohain toward jet propulsion?
- Who flew the Heinkel He 178 on its first flight, and when did it happen?
- How did the German Air Ministry initially assess the military value of the He 178?
- How quickly did jet aircraft move from experimental flight to military and then civilian use?
- What problem was Harry Coover actually trying to solve when he synthesized cyanoacrylate in 1942?
- What practical fields rely on the quantitative theory of branched chain reactions today?
- What rocket carried Sputnik 1 into orbit, and why was it originally designed for a different purpose?
- Why do the Van Allen belts matter for spacecraft shielding and crewed missions beyond low Earth orbit?
- Why did early meteorologists need to learn a new way of reading weather patterns from satellite images?
- Why did Gagarin eject from the capsule and land separately by parachute rather than riding it down?
- Why were Vostok 1's automatic controls preferred over manual controls, given uncertainty about human function in weightlessness?
- How did Alan Shepard's suborbital Freedom 7 flight differ from Yuri Gagarin's full orbital flight three weeks earlier?
- Why did Venera 1 need to be launched toward a point in space where Venus would be months later rather than where it currently was?
- What caused Venera 1 to lose contact with ground control before it reached Venus?
- What warning did Glenn's telemetry sensors give about the Friendship 7 heat shield, and was it accurate?
- Why did mission control decide to keep the retrograde rocket package attached during re-entry?
- Why did the first Mariner probe to Venus fail before Mariner 2 succeeded?
- Why did Leonov's spacesuit balloon outward in the vacuum of space, and how did that nearly strand him outside Voskhod 2?
- How did Luna 9 cushion its landing and stabilise itself on the Moon's surface using petal-like panels?
- How far did Venera 3 travel, and what tools did engineers use to calculate its interplanetary trajectory in 1965?
- Why couldn't Grissom, White, and Chaffee escape the capsule once the fire started?
- What design changes did NASA make to the Apollo command module after the fire?
- How many structural problems had Soviet engineers identified with Soyuz 1 before it launched?
- What sequence of technical failures caused the Soyuz 1 capsule to crash during re-entry?
- How did the Soyuz spacecraft design change after the accident, and why has it remained in use for so long?
- How close did Apollo 12 land to the Surveyor 3 probe, and why did that matter?
- Why has no later crew transfer between docked spacecraft used a spacewalk instead of an internal hatch?
- Why did the crew retreat into the lunar module Aquarius, and what problem did that create given its original design?
- What is a free-return trajectory, and how did it help bring Apollo 13's crew home safely?
- How did the docking adaptor used in Apollo-Soyuz allow incompatible American and Soviet spacecraft to connect?
- How did the Apollo-Soyuz docking protocols pave the way for the International Space Station?
- Why did British Airways and Air France launch Concorde's supersonic service simultaneously in January 1976?
- Why was Concorde retired in 2003 despite its speed record never being matched by another passenger aircraft?
- Why did NASA need to test the Space Shuttle's unpowered glide-and-landing profile before ever flying it in orbit?
- How was Enterprise carried aloft and released for its first free flight on 12 August 1977?
- How did Voyager 1, launched after Voyager 2, end up overtaking its twin within months?
- Where is formal program verification used today in situations where a software bug would be catastrophic?
- Why was STS-1 unusual in carrying astronauts on a spacecraft's very first flight?
- What engineering challenges did Soviet designers have to solve to build a probe that could survive on the surface of Venus?
- Why does the atmospheric pressure on Venus's surface make landing a spacecraft there so much harder than on Mars or the Moon?
- What robotic system did Ride help develop and then operate in orbit?
- How long did NASA's Deep Space Network keep receiving signals from Pioneer 10 after it left the solar system's major planets?
- Why had satellite data failed to corroborate the ozone loss earlier than the ground-based survey did?
- Why did the United States decline to send a spacecraft to meet Halley's Comet in 1986?
- How did Voyager 2 send data back to Earth across 2.7 billion kilometres on such a faint radio signal?
- Why does GPS accuracy depend on the kind of atomic-clock precision this work made possible?
- How did synthetic-aperture radar let Magellan map Venus's surface through its thick clouds?
- How did Magellan's synthetic-aperture radar see through Venus's permanent sulphuric acid cloud deck?
- How did the failure of Galileo's main antenna change the mission's data-return strategy?
- What complication delayed Mars Global Surveyor's aerobraking manoeuvre into its mapping orbit?
- What everyday technology depends on the atomic clocks made possible by laser cooling?
- How did Mars Pathfinder's airbag landing system work, and why was it a departure from prior methods?
- How many nations and assembly flights were eventually involved in building out the International Space Station from these first two modules?
- What condition was the space station in when Expedition 1 arrived in November 2000?
- How long has the International Space Station been continuously occupied since Expedition 1?
- How did Mars Odyssey use aerobraking to settle into its mapping orbit around Mars?
- Why is Mars Odyssey notable among spacecraft that have orbited other planets?
- What incident during the 1949 Air Force rocket-sled experiments led to the coining of Murphy's Law?
- How fast and how high did Concorde cruise compared to a standard passenger jet?
- What economic factors made Concorde's operations difficult despite decades of service?
- How did the rovers land on Mars, and why is that method notable?
- What modern technologies depend on the ultra-precise clocks built from frequency combs?
- What technical failures did the Hayabusa spacecraft survive during its mission to Itokawa?
- What design compromises made the Space Shuttle 'not quite safe enough'?
- Why was Curiosity too heavy for the airbag landing system used by earlier Mars rovers?
- How did the sky crane system lower Curiosity onto the Martian surface using cables?
- Why did NASA engineers call the landing sequence 'seven minutes of terror'?
- How was Gustano Pizzo's 1972 anti-hijacking device designed to work?
- Why was the patent never built despite being drawn up with careful engineering precision?
- What historical wave of hijackings motivated the invention in the first place?
- Why couldn't New Horizons slow down to orbit Pluto during its flyby?
- How long did it take for New Horizons' images to be transmitted back to Earth?
- Why did Juno's orbit-insertion burn have to be performed autonomously rather than by real-time commands from Earth?
- What did Cassini's final telemetry show about the spacecraft as it broke apart in Saturn's atmosphere?
- Why had rocket boosters historically been discarded or expensively refurbished rather than simply reflown?
- How did proving booster reuse change the economics of spaceflight?
- What payload did SpaceX launch on the Falcon Heavy's maiden flight, and where did it end up?
- Why must the Mars entry, descent, and landing sequence be fully automated?
- How does Starship's first-stage thrust compare to the Saturn V rocket?
- What happened during Starship's first and second integrated flight tests in 2023?
- Why did SpaceX describe both failed test flights as successful?
- How far is Voyager 1 from Earth, and how long does a radio signal take to reach it and return?
- What caused Voyager 1's telemetry to become garbled starting in late 2023?
- What failure modes might a weapons system dependent on trained pigeons introduce?
- How can a dead trout placed in flowing water move upstream without any muscular effort of its own?
- What ended Gaia's mission, and what happened to the spacecraft afterward?
- What risks has the ISS survived over its 25 years of continuous operation?
- What is the geoid, and why does an accurate model of Earth's shape matter for satellite navigation?
- How did Gladys West use computers at the Naval Surface Warfare Center to model Earth's gravitational anomalies?
- What happens to a GPS position fix if the underlying geodetic model of Earth's surface is inaccurate?
- What barriers did Gladys West face as one of few Black women mathematicians at Dahlgren in the 1950s?
- Why had Europe lacked full heavy-lift launch capacity since Ariane 5 retired in 2023?
- What payload did the Ariane 64's maiden flight carry, and how much mass did it deliver to low Earth orbit?
- How does the four-booster Ariane 64 configuration differ from the standard Ariane 6, and what capability does it restore?
- How does Ariane 64's launch cadence compare to SpaceX's Falcon 9?