Name: Why Did NASA Kill Cassini?
Uploaded: undefined
Duration: undefined

Nova

On September 15, 2017 NASA destroyed Cassini—on purpose. Why kill a multibillion-dollar spacecraft?

Why kill a multibillion-dollar  spacecraft?

Why Did NASA Kill Cassini?

Koch Foundation

NOVA Science Trust Logo

<div class="rich-text">On September 15, 2017 NASA destroyed Cassini—on purpose. Why kill a multibillion-dollar spacecraft?
</div>

<div class="rich-text">On September 15, 2017 NASA destroyed Cassini—on purpose. Why kill a multibillion-dollar spacecraft?</div>

Space & Flight

<div class="rich-text"><h3>
 Why Did NASA Kill Cassini?
</h3>

 Published September 15, 2017



 Brent Buffington
 
 : Why get rid of a two billion dollar asset that's orbiting Saturn? It's still executing amazing science, why get rid of it?“



 Onscreen
 
 : In 1997 The Cassini-Huygens spacecraft launched from Cape Canaveral and headed to Saturn.
 
 Since then it’s been busy: 2.5 million commands executed, 4.9 billion miles traveled, 453,048 pictures taken and on September 15, 2017 Cassini was destroyed.
 

 On purpose.
 

 But why?
 


 Buffington
 
 : The short answer is, we're almost out of fuel. But also before we run out of fuel, we have to adhere to what's called planetary protection.
 


 Onscreen
 
 : Planetary protection is the principle of avoiding biological contamination of celestial bodies.
 


 Buffington
 
 : This is to make sure that we don't pollute a pristine environment that could harbor life, with our own microbes that could be on our spacecraft.
 


 Onscreen
 
 : Cassini found a global ocean under the ice of one of Saturn’s moons, Enceladus.
 

 Some scientists believe Enceladus contains the perfect conditions for life.
 


 Buffington
 
 : The last thing we want to do is go back to Enceladus in 50 years and land on the surface and discover life, the biggest discovery in the history of mankind, but only to find out five years later, after more analysis, that it was in fact planted there by us because our dirty spacecraft with Earth microbes impacted Enceladus.
 

 So we want to definitively get rid of the spacecraft, and keep all of these environments that are pristine right now, pristine.
 

 So what are the options?
 


 Onscreen
 
 : #1 Crash into an uninhabitable rock.
 


 Buffington
 
 : You can hit something. So you can hit an icy satellite that's not a high value target from a habitability point of view, a big icy rock like Rhea or Iapetus or some of these moons
 


 Onscreen
 
 : #2 Orbit Saturn indefinitely.
 


 Buffington
 
 : You can stay in the Saturn system but go into some highly stable orbit and it stays there for hundreds and hundreds of years.
 


 Onscreen
 
 : But the chosen solution is…
 

 #3 Burn up in Saturn’s atmosphere.
 


 Buffington
 
 : With one Titan flyby you can jump the entire ring system and put yourself in an orbit that actually impacts Saturn
 


 Onscreen
 
 : On the way Cassini executes 22 close orbits of Saturn, gathering data.
 


 Buffington
 
 : And if it goes well, papers will be written on the scientific discoveries for many many years.
 

 But if it doesn’t go well we’ve still met our engineering objective and that’s definitively disposing of our spacecraft.
 


 Onscreen
 
 : Cassini’s destruction helps ensure that if we ever find life here, it’ll be native and not a tourist from Earth.
 
</div>

United States

Northern Mariana Islands

Puerto Rico

American Samoa

Guam

U.S. Virgin Islands

U.S. Minor Outlying Islands

US & Territories

NOVA investigates the story of cannabis from the criminalization that has disproportionately harmed communities of color to the latest medical understanding of the plant. What risks does cannabis pose to the developing brain? How much do we know about its potential medical benefits? As cannabis becomes socially accepted, scientists are exploring its long-term health consequences. (Premiered September 29, 2021)Check out a previously recorded panel discussion and audience Q&amp;A featuring experts and producers from "The Cannabis Question" <a href="https://youtu.be/nSTT5RZ_hxA">here</a>.

As state-legalized cannabis spreads, NOVA explores its little-known risks and benefits.

The Cannabis Question

A 2006 composite image from NASA's Hubble Space Telescope and Spitzer Telescope shows the chaos of baby stars in the Orion nebula some 1,500 light-years away. Image Credit: NASA/JPL-Caltech/STScI

With the upcoming launch of the James Webb Space Telescope, the Hubble era is gradually drawing to a close. Here are some highlights from the countless wonders Hubble has shown us during its 31 years in space.

10 spectacular Hubble Space Telescope images

A statue of Zheng He at the Sam Poo Kong Temple in Java, Indonesia. Image Credit: Budianto Santosa, Shutterstock

In the 1400s, Zheng He sailed thousands of miles around Asia and Africa in ships the size of soccer fields, spreading Chinese innovations like compasses and gunpowder in the process.

Transcript

Credits

Support Provided By