This composite picture reveals the three small worlds NASA Stardust spacecraft encountered throughout its 12 yr mission. Stardust carried out a flyby of asteroid Annefrank in 2002, Comet Wild in 2004, and Tempel 1 in 2011. Credit score: NASA.
Amid the colourful colours of worlds, massive and small, within the Smithsonian Establishment’s Kenneth C. Griffin Exploring the Planets Gallery sits Stardust, a curiosity that travelled 2.88 billion miles (4.63 billion kilometers), visited an asteroid, bought sandblasted by a comet, then screamed again to Earth quicker than any human-made object in historical past. After a blazing reentry, it landed underneath parachutes in Utah’s desert salt flats, turning science fiction into actuality.
Eerily backlit in icy blue tones paying homage to the frigid locations it as soon as visited, Stardust was America’s first effort to get better extraterrestrial materials from past the Moon: over 10,000 micron-sized grains from a comet whose composition had seen scant change in 4.5 billion years. It was a beguiling reminder that science’s grandest rewards usually sprout from its tiniest treasures.
“Stardust … represents a reversal in conventional exploration methods,” stated Mission Supervisor Ken Atkins of NASA’s Jet Propulsion Laboratory (JPL) in a 1997 assertion concerning the mission. “As a substitute of taking expensively-packaged devices to the goal of curiosity, Stardust [brings] samples of the targets to laboratories on Earth.”
However this sample-return capsule, curated by the Smithsonian since 2008, is just a part of the $199.6 million story. Conceived in 1980 however thought of unworkable on the time, NASA green-lighted Stardust for growth in 1995 as a quicker, higher, cheaper Discovery mission. Led by Principal Investigator Don Brownlee of the College of Washington, Stardust took intention on Wild-2 (pronounced Vilt-2), a long-period comet whose 43-year photo voltaic orbit was hewn down to 6 years by a detailed encounter with Jupiter.
Wild-2’s path adjustments
In September 1974, Wild-2 grazed Jupiter at lower than 600,000 miles (960,000 km) and the enormous planet’s gravity perturbed its orbit, thrusting it deep into the inside photo voltaic system to turn into a short-period comet. A circuitous path that when carried it from jovian distance nearly so far as Uranus was dramatically reshaped, the comet’s aphelion shrinking to five.3 AU and its perihelion to 1.59 AU. (One astronomical unit, or AU, is the same as the typical Earth-Solar distance of 93 million miles or 150 million km.)
Wild-2 was found in January 1978 by Swiss astronomer Paul Wild (1925-2014). Particles of the comet can be “soft-captured” by Stardust for return to Earth: “The samples … [will be] extraordinarily small,” defined Brownlee in a 1999 assertion. “Even when a ton of pattern have been returned, the primary data … would nonetheless be recorded on the micron degree, and the evaluation would nonetheless be achieved a single grain at a time.”
Roughly the scale of an workplace desk, Stardust had eight hydrazine thrusters, 5 science devices, and two photo voltaic arrays. Three spaced-armor composite bumpers, known as Whipple Shields after U.S. astronomer Fred Whipple (1906-2004), who conceived them as a method of defending spacecraft from micrometeoroid and different impacts, guarded Stardust towards a raging hailstorm of cometary mud.
A JPL-built navigation digicam would map Wild-2’s nucleus to glean clues about its origins, morphology and mineralogy. Germany’s Max-Planck Institute equipped a mass spectrometer and JPL’s dynamic science experiment measured the comet’s inner construction. The College of Chicago equipped a dust-flux monitor to trace the ebb and circulate of cometary materials and its impression on Stardust.
And the College of Washington’s tennis-racket-sized pattern collector would take specimens from Wild-2. It was full of aerogel, an ultra-lightweight silicon dioxide foam able to withstanding pressures hundreds of instances higher than its personal mass. Cometary particles would bury themselves into this porous, spongelike “strong smoke,” leaving well-defined tracks for post-mission evaluation.
A ‘pleased return of the dear mud’
Stardust rose from Florida’s Cape Canaveral Air Power Station atop a Delta II rocket at 4:04 p.m. EST on Feb. 7, 1999. Watching the launch have been Wild and Whipple. “If my life span is greater than 80 years,” Wild wrote to NASA’s Stardust team, “I’d significantly wish to witness the pleased return of the dear mud and to examine at shut vary a wee little bit of what I first spied from very afar.”
Stardust barreled into deep area at 70,000 mph (114,000 km/h), quick sufficient to cross the contiguous U.S. in two minutes. After a full photo voltaic orbit, it headed house and swept previous Earth on Jan. 15, 2001, selecting up a gravitational enhance to achieve Wild-2.
However earlier than assembly Paul Wild’s comet, one other goal lay forward: the stony asteroid 5535 Annefrank, named for the teenaged Jewish diarist who died within the Holocaust. Stardust handed the prism-shaped asteroid at a distance of 1,913 miles (3,079 km) on Nov. 2, 2002, revealing an object twice as massive as scientists had predicted, its floor riven by a number of impression fractures.
A yr later, the flattened ice-rock sphere of Wild-2’s nucleus got here hauntingly into view, as big as three Brooklyn Bridges laid end-to-end. Right here, Stardust’s Whipple Shields proved their mettle. “Identical to in Star Trek, we have now our shields up,” quipped Program Supervisor Tom Duxbury of JPL in information tales on the time. Hurtling inbound at 13,680 mph (21,960 km/h), particle impacts at these blistering velocities may show catastrophic.
On Jan. 2, 2004, after 2.3 billion miles (3.7 billion km) traveled, Stardust handed Wild-2 on the comet’s sunward-facing aspect at a distance of 147 miles (237 km). Its 72 pictures revealed the three.4-mile-wide (5.5 km) nucleus as a battered, potato-like lump, riddled with flat-floored depressions, mansion-sized boulders, and sheer, near-vertical cliffs, possible attributable to impression craters or fuel vents. Ten such vents have been lively through the flyby.
Stardust’s pattern collector was retracted six hours later, stowed and sealed contained in the sample-return capsule. “Comet Wild-2 gave up its particles, but it surely didn’t achieve this and not using a battle,” admitted Duxbury. “Our knowledge signifies we flew by means of sheets of cometary particles that jostled the spacecraft, and that on a minimum of 10 events, the primary layer of our shielding was breached. Glad we had a pair extra layers.”
After a two-year homebound journey, Stardust handed the Moon and crossed the ultimate 240,000 miles (370,000 km) of cislunar area in solely 16.7 hours, 5 instances quicker than the Apollo astronauts did. It jettisoned the blunt-bodied sample-return capsule, then executed a divert manoeuvre to keep away from reentering Earth’s ambiance itself.
On Jan. 15, 2006, the sample-return capsule slammed into the ambiance at 28,850 mph (46,440 km/h), eclipsing Apollo 10 because the quickest reentry of any human-made object in historical past. Shielded from deceleration forces of 34G and temperatures of 5,250 levels Fahrenheit (2,900 levels Celsius), it slowed from Mach 36 to subsonic speeds in 110 seconds, then parachuted into the U.S. Military’s Utah Coaching and Take a look at Vary, 80 miles (130 km) west of Salt Lake Metropolis.
A key constructing block for all times
Recovered in wonderful situation, the blackened and charred capsule was opened two days later. Along with hundreds of cometary particles, interstellar mud from exterior the photo voltaic system was embedded within the aerogel. Natural compounds from olivine and pyroxene to iron and copper sulphate minerals that possible fashioned within the presence of water have been discovered.
Glycine, an amino acid and a key constructing block for all times, was additionally current. “The invention of glycine,” stated Carl Pilcher of NASA’s Astrobiology Institute, “strengthens the argument that life within the Universe could also be widespread, reasonably than uncommon.”
On Jan. 29, 2006, Stardust entered hibernation. However one other mission lay forward. In July 2005, NASA’s Deep Affect probe crashed a high-speed projectile into Comet Tempel-1 however was unable to view the impression website. NASA accepted the New Exploration of Tempel-1 (NExT), utilizing Stardust for the primary cometary “revisit,” to re-examine the impression website and observe adjustments in its nucleus.
One other enhance from Earth in January 2009 introduced the spacecraft inside 112 miles (181 km) of Tempel-1 on Jan. 14, 2011, allowing intensive images of the 4.7-mile-wide (7.6 km) nucleus. Photographs of the impression space revealed a 490-foot-wide (150 m) melancholy with a brilliant central mound, possible prompted when particles collapsed again into the crater’s yawning bowl.
For Stardust, now low on gas, the tip was nigh. In March 2011, it fell silent. However others would comply with. NASA’s Genesis probe (regardless of struggling a parachute failure) introduced house photo voltaic wind particles in September 2004 and Japan’s two Hayabusa missions returned samples from the stony asteroid Itokawa in June 2010 and carbon-rich Ryugu in November 2020. NASA’s OSIRIS-REx did likewise for asteroid Bennu in September 2023.
Associated: Listing of present and upcoming area missions
Nearer to house, in November 2020 China’s Chang’e-5 introduced the primary lunar samples again to Earth in over 4 many years. And searching forward, Japan plans to gather soil from Mars’ moon Phobos in 2026, whereas NASA’s at the moment paused Mars Pattern Return (MSR) glimmers with tantalizing promise on the horizon for the 2030s.