SpaceX aces 100th rocket landing after Dragon cargo ship launch to space station

CAPE CANAVERAL, Fla. — SpaceX launched its 31st rocket of the year early Tuesday (Dec. 21), sending a used Dragon cargo capsule toward the International Space Station before nailing the company's 100th landing. 

A new two-stage Falcon 9 rocket blasted off from Launch Complex 39A here at NASA's Kennedy Space Center at 5:07 a.m. EST (1007 GMT), kicking off the company's 24th cargo resupply mission to the orbiting lab for NASA. The Dragon is packed with more than 6,500 pounds (2,900 kilograms) of supplies, scientific experiments, and hardware for the crew of Expedition 66 on the station.

About eight minutes after liftoff, the Falcon 9's first stage returned to Earth, landing on one of SpaceX's drone ships in the Atlantic Ocean in a smooth touchdown. The massive ship, called Just Read the Instructions, is one of SpaceX's three drone ships that are designed to serve as floating landing platforms and return them to port for later reuse. 

"There it is! So this is the first landing for this particular booster but the 100th successful landing for an orbital class rocket," said Andy Train, a SpaceX production supervisor, in a live webcast. "What a way to end off the year."

 Related: How SpaceX's Dragon space capsule works (infographic)  

Dragon is scheduled to arrive at the station just under 24 hours after liftoff, docking with the orbital outpost on Wednesday morning (Dec. 22) around 4:30 a.m. EST (0930 GMT) — just over 24 hours after the launch. NASA astronauts Raja Chari and Tom Marshburn will monitor the Dragon as it docks itself to the space station. You can watch the docking live online, courtesy of NASA TV, beginning at 3 a.m. EST (0800 GMT). 

Weather officials at the Space Force's 45th Weather Squadron predicted iffy weather for the mission’s first launch attempt, scheduled for Dec. 21, with the main concerns being cumulus and thick clouds as well as the electric field rule. Luckily, mother nature cooperated and the rocket was able to get off the ground right on time. 

A thick cloud layer hung over the space coast, blocking views of the rocket as it climbed to space; however, those clouds made for good acoustics as the roar of the engines thundered overhead. 

The first-stage booster featured in today's flight, known as B1069, was a first-time flier, making its launch debut, while its Dragon counterpart has already flown once before as part of the CRS-22 mission earlier this year.

After its on-time liftoff, the rocket's first stage returned to Earth marking SpaceX's 100th recovery of a Falcon first stage since SpaceX recovered its first booster in 2015

Related: Watch a SpaceX rocket ace landing on a drone ship in stunning new video

Last Dragon launch of 2021

SpaceX's gumdrop-shaped CRS-24 capsule is the sixth Dragon spacecraft to launch this year, five of which traveled to the space station and back. (The other carried the Inspiration4 crew into space for a three-day mission to orbit the Earth.)

It's packed with a treasure trove of science payloads as well as supplies and treats for the crew, which include festive delights such as turkey and fruitcake, not to mention some Christmas presents for the astronauts.

"We're going to have some gifts for the crew, and we're going to fly some special food for Christmas dinner," Joel Montalbano, ISS program manager for NASA, said during a prelaunch news briefing on Monday (Dec. 20). "We have some turkey, green beans, and everyone's favorite fruit cake." 

Also onboard are a variety of medical payloads that will help benefit astronauts as well as people on Earth. One such payload, called Bioprint FirstAid, will demonstrate how a handheld device can print a Band-Aid using the astronaut's own skin cells. 

This type of patch can help accelerate the healing process as well as mitigate any wound healing issues that could crop up during spaceflight. It also has implications here on Earth as it could provide safer, more flexible healing anywhere on Earth, even in remote areas. 

SpaceX's Dragon CRS-24 cargo ship is seen as it separates from its Falcon 9 rocket upper stage after launching into orbit on Dec. 21, 2021 to deliver Christmas gifts and other NASA supplies to the International Space Station. It will arrive on Dec. 22, 2021. (Image credit: SpaceX)

The Host-Pathogen experiment will look at cells taken from various crew members at various stages during flight to assess how microbes affect the body's immune response. Researchers will take the samples collected and expose them to both "normal" bacteria and bacteria that's been exposed to spaceflight. This could lead to an immune system boost for astronauts during spaceflight as well as to more effective care of patients here on Earth with compromised immune systems. 

The Multi-Variable Plant Platform (MVP-Plant-01) will monitor the development of plant roots and shoots in microgravity as part of an effort to understand how plants adapt to changes in their environments. The research could help growers create more robust plants that can withstand harsh environmental changes, like long droughts.  

In total, there are more than 6,500 pounds (2,900 kg) of cargo that will help the astronauts perform a variety of research experiments as well as help to restock the station. 

It's been a busy year on station with a total of eight different cargo ships, five crew missions, and two different space tourist groups, one of which carried a Russian film crew. (The other carried Japanese billionaire Yusaku Maezawa and his assistant on a 10-day journey to the ISS.)

2021 also saw the delivery of two different Russian modules as well as the installation of a new set of solar arrays to help increase the power to the orbiting outpost, with two more to be installed next year.

"A huge thanks to the ISS team around the globe for what we've been able to accomplish this year," Montalbano said. "As you know, we work and operate around pandemic constraints and the teams have just been outstanding."

Falcon 9 rocket records

"It's been a record-breaking year for SpaceX," Sarah Walker, Dragon mission manager for SpaceX said during a prelaunch news briefing on Dec. 20. "This is our 31st and final launch for 2021, putting us a step above the 26 launches we completed last year."

It also marks a major recovery milestone as the 100th successful recovery of a first-stage booster for the company. SpaceX began recovering rockets in 2015, with the milestone landing occurring on the anniversary of the very first recovery. 

SpaceX relies on a fleet of reusable rockets in order to keep up such a high launch cadence. This means that instead of using a brand-new rocket each time, the company can refly its recovered boosters many times over.

Of the 31 launches, only two flew on brand new rockets, the rest were on one of SpaceX's flight-proven boosters. That's thanks to a set of upgrades the Falcon 9 received in 2018, as well as a fleet of drone ships to catch the returning boosters. 

SpaceX now has three of these massive ships at its disposal: "Of Course I Still Love You," "Just Read the Instructions" and the newest ship on the block, "A Shortfall of Gravitas." 

The company recently transferred its most prolific ship, "Of Course I Still Love You", to the West Coast where the boat will facilitate recovery operations for missions that launch from SpaceX's California-based launch pad at Vandenberg Space Force Base. 

That enabled SpaceX to pull off a hat trick for its final launch act of 2021, launching a total of three rockets in less than 72 hours. As such, the company had all three of its massive drone ships stationed out in the ocean for the first time ever.

The booster featured in today's flight is the most recent rocket to join SpaceX's fleet of veteran rockets, logging its first successful launch and landing. After it is offloaded, the booster will be inspected and prepped to fly again. 

Now that Dragon has made it to orbit, it will spend the next day chasing down the space station before it docks itself to the orbital outpost. 

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Amy Thompson
Contributing Writer

Amy Thompson is a Florida-based space and science journalist, who joined Space.com as a contributing writer in 2015. She's passionate about all things space and is a huge science and science-fiction geek. Star Wars is her favorite fandom, with that sassy little droid, R2D2 being her favorite. She studied science at the University of Florida, earning a degree in microbiology. Her work has also been published in Newsweek, VICE, Smithsonian, and many more. Now she chases rockets, writing about launches, commercial space, space station science, and everything in between.