TROY
A FIELD GUIDE TO THE SPIRIT ROVER
Ten chapters on the golf-cart-sized geologist that outlasted its warranty by twenty times over, climbed a range of hills no rover had attempted before, stumbled into one of its best discoveries by accident, and finally became trapped in a patch of ground its own engineers named after a siege that couldn't be won. Scroll to begin the mission.
BEGIN — CHAPTER 01 →Named by a nine-year-old, in a contest with ten thousand entries
Spirit and its twin, Opportunity, formed NASA's Mars Exploration Rover mission, part of the broader Mars Exploration Program searching for evidence of past water.[7] Their names came from a NASA-sponsored student essay contest, sponsored jointly with The Planetary Society and LEGO, that drew nearly 10,000 entries before Spirit and Opportunity were chosen.[3]
Spirit launched first, on June 10, 2003, aboard a Delta II rocket from Cape Canaveral, with Opportunity following about a month later.[8] The two were deliberately targeted at opposite sides of Mars, each chosen because orbital imagery suggested liquid water might once have shaped the ground there.[6]
Twenty-eight bounces, named for seven astronauts
Spirit struck the Martian surface inside Gusev Crater at 04:35 UTC on January 4, 2004, hitting at roughly 14 metres per second before bouncing 28 times across the ground, cushioned by airbags, and rolling to a stop 250 to 300 metres from its first impact.[6]
The landing site was named Columbia Memorial Station, honouring the seven astronauts killed when Space Shuttle Columbia broke apart during re-entry on February 1, 2003 — less than a year before Spirit touched down.[6]
The size of a golf cart, seven times heavier than Sojourner
At 185 kg, Spirit dwarfed Pathfinder's tiny Sojourner rover from 1997.[6] Select a component.
Basalt plains where a lake was expected
Gusev Crater was chosen because its flat floor, fed by an 800-km outflow channel called Ma'adim Vallis, made a former lake bed seem near-certain.[3] Instead, Spirit's first months found the plains covered in volcanic basalt — any lake sediments long since buried under later eruptions.[3]
Designed for a 90-sol mission, Spirit was still driving nearly six years later — a mission that eventually stretched to 2,208 sols of contact, more than twenty times its original warranty.[10]
Chasing older rock, uphill
With the plains disappointing, mission scientists sent Spirit toward the Columbia Hills, about 3 km from the landing site, hoping for rock old enough to have escaped the basalt flows.[3] The gamble paid off: among the hills, Spirit found minerals like goethite that form only in the presence of water, along with rocks visibly altered by past moisture — the clearest sign yet that Gusev's history involved more than lava.[9]
A broken wheel accidentally became an instrument
In 2006, Spirit's right front wheel stopped turning entirely. Engineers had the rover drive backward, dragging the dead wheel like a plough — and that dragging motion scraped up bright, almost pure silica deposits from just beneath the surface near a feature called Home Plate.[3] Nearly pure silica on Earth typically forms around hot springs or steam vents, making the accidental discovery one of the strongest pieces of evidence for a past hydrothermal environment anywhere the rovers explored.[9]
A sand trap that months of effort couldn't escape
In April 2009, Spirit's wheels broke through a crusted surface into soft, hidden sand at a site engineers named Troy — a nod to a siege nobody wins. For months, controllers tried a careful sequence of small movements to work the rover free, but by January 2010, NASA concluded Spirit was permanently embedded and reclassified it as a stationary science platform.[4]
Unable to tilt toward the Sun, unable to survive the cold
Stuck at a fixed, unfavourable tilt in Troy, Spirit could no longer angle its solar panels toward the low winter Sun the way a mobile rover could. With power dropping, its last communication reached Earth on March 22, 2010 — Sol 2210. NASA's own end-of-mission report concluded Spirit most likely succumbed to the extreme cold of its fourth Martian winter.[5]
More than a hundred commands sent after it fell silent
A search that continued for over a year after the silence
NASA radiated over 1,400 commands toward Spirit after its last contact, hoping for a response, before search and recovery efforts formally concluded on July 13, 2011 — NASA had already declared the mission over on May 25, 2011.[5] Its twin, Opportunity, kept driving for eight more years after Spirit fell silent.
Sources cited throughout this guide
Bracketed numbers in the text above correspond to the sources below.