A new segment here on Rocket Roundup is “This Week in Rocket History” where, as the name suggests, we’ll be covering interesting and/or significant rocket launches that took place roughly around this week in history.
Our first historical overview is of the Stardust mission, which launched on February 7th, 1999 from Cape Canaveral in Florida on a Delta II rocket and went straight into a heliocentric orbit after a 27-minute burn, taking it on a path around the sun for an Earth gravity assist later in 2,001.
The sample return mission collected dust samples from the coma of comet 81P/Wild (also known as Wild 2) and returned them to Earth for study in 2006. This was the first-ever comet sample return mission. The sample collector used aerogel — a very low-density, gel-like, synthetic material — which would then trap and hold in place particles of dust as they flew into the capsule.
In 2002, the spacecraft flew by asteroid 5535 Annefrank on its way to its primary encounter with comet Wild 2 in early 2004. The 5535 Annefrank encounter was primarily used as an engineering test in preparation for the encounter with Wild 2.
The encounter with comet Wild 2 officially began on January 2nd, 2004, even though the sample collector was deployed a week earlier, on December 24th. Fifty-one days later, on February 21, the encounter officially ended. During this time the spacecraft made several engine burns that took it as close as 237 kilometers (147 miles) to the comet.
After the flyby, Stardust performed a maneuver that would allow it to encounter Earth again in early 2006. Since the capsule itself had no propulsion, the spacecraft had to perform a series of maneuvers to send it back to Earth. Stardust needed to get close enough to Earth to release the sample return capsule while missing the atmosphere itself because only the sample return capsule was designed to survive atmospheric re-entry.
The capsule landed safely in Utah on January 15th, 2006.
After the sample return, the spacecraft went into hibernation in a heliocentric orbit but still had around twenty kilograms of fuel left. In 2007, the spacecraft’s mission was extended and renamed Stardust/NExT, which is a backronym for “New Exploration of Tempel 1”. This new, extended mission would perform a flyby of comet 9P/Tempel 1, nicknamed the Valentine Comet as Stardust was to meet it on February 15th, 2011.
This marked the first time an asteroid had been explored twice as Tempel 1 had already been visited (and crashed into by) Deep Impact in 2005.
Stardust/NExT got as close as 181 kilometers to Tempel 1 and took images to examine the comet and attempt to find Deep Impact’s, well, impact on the comet. While the impact site was observed, it was barely noticeable in the pictures, which was a bit anticlimactic but still gave us a lot of insight into the comet’s composition.
On the 24th of March 2011, Stardust conducted its last maneuver to burn the rest of its remaining fuel, which scientists then used to improve their fuel consumption estimation models. The spacecraft then sent its last acknowledgment ping and shut off.
And what about the returned samples from the original mission? Well, after the capsule landed and was recovered, it was opened in the lab, and inside were found at least a million microscopic samples and also around ten samples larger than 100 micrometers (0.1 mm), with the largest measuring around one millimeter.
Data from the mission was analyzed by a citizen science distributed computing project called Stardust@home. Several of these citizen scientists were credited in the scientific papers written using the data.
Some of the more exciting discoveries were the existence of various organic compounds in the samples, traces of liquid water, and glycine, which is a building block of organic life. Finding liquid water was a paradigm-shifting discovery, as comets were thought to never get warm enough to liquefy their water. As one NASA astrobiologist said, it “supports the idea that the fundamental building blocks of life are prevalent in space, and strengthens the argument that life in the universe may be common rather than rare”.
The capsule now resides in the National Air and Space Museum in Washington DC, alongside a sample of the aerogel used in the collection.
NASA JPL article