Comets have historically been seen as celestial harbingers, sparking awe and fear, but have become objects of scientific exploration.

• Comets were traditionally viewed as omens of change.
• Over the past 50 years, humanity's approach shifted from passive observation to active exploration.
• Questions about comet origins and formation have driven scientific curiosity.

The first probe to image Halley's Comet was launched in 1986, marking the beginning of comet exploration.

• Photographs from the first probe to Halley's Comet started to provide answers about comets.
• To deeply understand comets, more interactive exploration was needed, prompting the launch of two probes between 1999 and 2005.

The Stardust mission collected comet dust, while Deep Impact aimed to create a crater on a comet to study its internal structure.

• Stardust aimed to capture comet dust to analyze chemical makeup.
• Deep Impact's forceful approach involved crashing into a comet to observe the resulting crater and debris.

Both Stardust and Deep Impact missions became unexpectedly linked through their interactions with Comet Tempel 1.

• Despite targeting different comets, both missions were linked by Tempel 1.
• Tempel 1's study provided an opportunity to understand the comet's core.

Before Stardust and Deep Impact, several probes had visited comets, but mysteries about their internal structure and composition remained.

• By the early '90s, comets were enigmatic despite several spacecraft visits.
• Only a few comets had been visited, and while data was collected, many questions persisted.

The Deep Impact mission was designed to study the internal structure of comets by creating a crater in Comet Tempel 1.

• NASA's plan involved an impactor spacecraft to collide with a comet and analyze the resulting crater.
• Deep Impact targeted Comet Tempel 1 with a budget of $330 million.

Deep Impact faced challenges en route to Tempel 1 but successfully recovered and continued its mission.

• Deep Impact launched in 2005 but encountered a minor programming issue post-launch.
• After resolving the issue, the spacecraft traveled 429 million km to Tempel 1.

Deep Impact successfully created a crater on Tempel 1, but a dust cloud obscured the view of the impact site.

• The impactor crashed into Tempel 1, generating a bright flash.
• Despite the successful collision, the resulting dust cloud hindered photographic analysis of the crater.

Stardust was launched in the late '90s to collect samples from Comet Wild 2 and analyze their isotopic composition.

• Stardust was designed to capture stardust from comets, aiming to confirm theories about their origins.
• The mission used aerogel to gently capture high-speed particles.

Stardust's visit to Comet Wild 2 revealed its unexpected geological activity and the absence of craters.

• Comet Wild 2 presented an active surface with features like pinnacles and cliffs.
• The absence of craters on Wild 2 suggested a self-renewing or active surface.

Stardust was repurposed as Stardust NeXT to revisit Comet Tempel 1 and complete Deep Impact's mission.

• After completing its mission to Wild 2, Stardust was redirected to Tempel 1 as Stardust NeXT for further study.
• Stardust's revisit provided a chance to observe changes on Tempel 1's surface over time.

Stardust NeXT successfully imaged Tempel 1's surface, revealing the impact crater and changes since the Deep Impact mission.

• Stardust NeXT provided images of the Deep Impact crater, showing Tempel 1's porous surface.
• The mission observed new geological changes, confirming the dynamic nature of Tempel 1.

The Stardust and Deep Impact missions enhanced our understanding of comets, their role in our solar system, and the potential origins of life.

• Deep Impact's extended EPOXI mission continued to study comets until 2013.
• Stardust's discoveries about comets' origins and the presence of organic materials reshaped scientific theories.