NASA just sent a spacecraft on a one-way mission to an asteroid — and once it gets there, it's going out with a bang.
At 10:21 p.m. local time on Tuesday (Nov. 23), NASA's asteroid-deflecting Double Asteroid Redirection Test (DART) lifted off from Vandenberg Space Force Base in California, carried by a SpaceX Falcon 9 rocket. DART now has a 10-month journey ahead of it until it reaches its destination: the binary asteroid system Didymos.
When DART arrives, the 1,210-pound (550 kilograms) spacecraft will fling itself into Didymos' orbiting moonlet Dimorphos while traveling at a speed of approximately 15,000 mph (24,000 km/h).
Related: The 7 strangest asteroids: Weird space rocks in our solar system
"It was a beautiful, beautiful launch, tremendously exciting," Thomas Statler, a program scientist in the Science Mission Directorate's Planetary Science Division at NASA Headquarters, said during NASA TV's broadcast of the launch on YouTube.
NASA launched DART to test kinetic deflection as a strategy for protecting Earth against large asteroids that may threaten our planet. Didymos measures around 2,560 feet (780 meters), wide, while Dimorphos is about 530 feet (160 m) across. The asteroid doesn't pose a threat to Earth, but as a binary system it offers NASA the opportunity to measure how a collision with the smaller body, Dimorphos, will affect the moonlet's orbital path around the asteroid's larger body. This will help NASA engineers figure out how much force is required to nudge an asteroid away from a potential collision course with Earth, Live Science previously reported.
DART will arrive at Didymos in late September to early October 2022. The collision will be guided by autonomous navigation software, aided by an onboard camera: the Didymos Reconnaissance and Asteroid Camera for Optical navigation (DRACO). Not only will DRACO help guide DART to the asteroid, it will also snap images of the spacecraft's last moments, which DART will stream back to Earth in real-time before smashing into the asteroid, according to the Johns Hopkins University Applied Physics Laboratory. (Johns Hopkins APL built the DART spacecraft and and is managing the mission for NASA's Planetary Defense Coordination Office, a representative told Live Science in an email.)
"Ready to handle whatever space throws at us"
But before DART takes its high-speed dive toward oblivion, the spacecraft may face additional challenges during its journey, said Angela Stickle, a planetary scientist at Johns Hopkins APL and DART impact modeling working group lead.
"Like for other missions, being in space is of course a risk; there are other hazards out there aside from large asteroids," Stickle told Live Science in an email. "The operations team has developed plans for any anomalies that the spacecraft may experience and ways to recover from things, like safe mode; we’ve run a number of full mission simulations to make sure the team is ready to handle whatever space throws at us," Stickle said.
To prepare for potential space hazards, engineers run numerous simulations and perform tests "that cycle through the worst possibilities," said Elena Adams, a systems engineer at Johns Hopkins APL and DART missions systems engineer. They explored scenarios such as the asteroid not being precisely where they expected it to be in its orbit; the target Dimorphus being smaller or dimmer than expected; and the spacecraft proving harder to control than indicated by tests, Adams told Live Science in an email.
And the testing doesn't end after launch. With DART underway, Adams and her colleagues will test their asteroid-tracking algorithms by training them on Jupiter's moons, Adams explained.
"We will be looking at [the] emerging of Europa and Io from behind Jupiter and making sure that our algorithms recognize the moons and are able to track them, as we would with Dimorphos emerging from behind Didymos," Adams said. "This test with Jovian moons is just one of the multiple tests we conduct in flight to ensure everything works as expected."
"A provocative and dangerous act"
Despite all these preparations and precautions, the launch faced an unexpected risk that arose just last week, when on Nov. 15, the Russian Ministry of Defense deployed an anti-satellite (ASAT) missile that destroyed a decommissioned Soviet satellite, Cosmos 1408, in low-Earth orbit. The explosion created a debris cloud directly in the path of the International Space Station (ISS), jeopardizing the seven astronauts and cosmonauts onboard and requiring them to seek shelter in the station's transport capsules, Live Science sister site Space.com reported.
The danger posed by the ASAT detonation and subsequent debris cloud was significant. Bits of space junk can travel at speeds exceeding 17,500 mph (28,000 km/h), and even a tiny fragment measuring just 0.5 inches (1.3 centimeters) wide could cause irreparable damage to the ISS, possibly even shutting down the station for good, Live Science previously reported.
Antony Blinken, the U.S. Secretary of State, tweeted condemnation for "Russia's reckless test of a direct-ascent anti-satellite missile against its own satellite, creating space debris that risks astronauts' lives, the integrity of the International Space Station, and the interests of all nations." NASA administrator Bill Nelson said that he was "outraged by this irresponsible and destabilizing action," according to a statement.
Nations worldwide also criticized Russia for conducting the unannounced test, with Japan's foreign minister calling it "irresponsible behavior," and Australia's defense minister proclaiming the test "a provocative and dangerous act," according to Space.com.
The debris cloud will linger for years, and NASA is closely monitoring the remnants of the destroyed spy satellite to assess the risk to the ISS and to future launches.
"The cataloging of the total number of identifiable pieces of debris is ongoing, with teams assessing the risk levels to conduct various mission activities," NASA representatives told Live Science in an email. "NASA will work with U.S. Space Command to ensure our spacecraft avoid orbital debris and safely achieve its intended orbit. Any changes to launches will be updated, as needed."
But now with DART safely on its way, the next big collision that mission control has on their minds is the planned collision with Didymos in 2022. When that happens, DART will disintegrate in a smashing finale.
"We’ll know right away whether we successfully impacted Dimorphos; the loss of signal from DART will tell us that, which will be nice," Stickle said. "After the actual impact, ground-based telescopic observations of the Didymos system will help determine how much we changed the orbital period for Dimorphos around its parent asteroid Didymos. We will be observing the Didymos system for several months following impact to determine just how much the orbital period changes."
Want to keep up with DART as it travels through space? Get mission updates at Live Science and Space.com and by following NASA on Twitter, Facebook and Instagram (check for the hashtags #DARTMission and #planetarydefense).
Originally published on Live Science.
