CAPSTONE mission is Moon-bound, after less rocketry than expected
China rubbishes NASA suggestion it wants Luna all to itself
Final update NASA and commercial space outfits Rocket Lab and Advanced Space have collectively announced that the Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment – CAPSTONE – mission has left Earth orbit and is on its way to Luna.
The CAPSTONE mission plan called for the satellite to launch from New Zealand atop a Rocket Lab Electron launch vehicle, then enter Earth orbit before a series of eight burns accelerated it to over 40,000km/h – enough to escape our planet's gravity and send it towards the Moon.
That plan went better than expected: last Friday Rocket Labs announced that the sixth orbit-raising burn was so successful it removed the need for a planned seventh burn.
MISSION UPDATE: Separation success!— Advanced Space (@AdvancedSpace) July 4, 2022
Our #CAPSTONE spacecraft has released from @RocketLab’s Photon upper stage and started its solo journey to the Moon. The pathfinder is scheduled to arrive at its lunar orbit on Nov. 13.
Learn More: https://t.co/z08vYj0Q7k pic.twitter.com/VOGSafiDpR
On Monday, the final burn did the job of placing CAPSTONE in a ballistic lunar transfer trajectory.
The distance between Earth and Luna is around 384,400km on average. CAPSTONE's journey will see it traverse more than 1.5 million kilometers on an orbit that NASA describes as a "sinuous track [that] follows dynamic gravitational contours in deep space" and uses the Sun's gravity to send the probe towards the Moon.
China has rebuffed assertions made by NASA's highest ranking official that it wants to take over the Moon. NASA administrator Bill Nelson told German media outlet Bild earlier this month that there was concern "about China landing on the Moon and saying 'It's ours now, and you're staying out.'" Nelson also mentioned China's robotic space grappling arm and suggested the nation wants to control the Moon's ice deposits. Chinese foreign ministry spokesman Zhao Lijian responded by calling the remarks "a smear campaign against China's normal and reasonable outer space endeavors."
The journey will take four months – rather longer than the three-day transfer time for the Apollo missions.
CAPSTONE's going slower because, as an uncrewed mission, speed is not of the essence – also because the ballistic trajectory uses less fuel and is therefore cheaper. Rocket Lab states that it can launch its Electron rocket for under $5 million.
Electron rockets can hoist 300kg into space. On this mission that included the Photon spacecraft that elevated CAPSTONE until it was on its way to Luna.
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NASA boffins will spend the next four months nudging CAPSTONE towards its destination.
Once it arrives, CAPSTONE will settle into a near rectilinear halo orbit – an orbit that oscillates in a shape like a crown and always keeps Earth in view. It's the same orbit NASA plans to use for the Lunar Gateway – an orbiting station it will use for future crewed Moon missions. The Gateway may also play a role in missions beyond Earth's immediate neighborhood. ®
Updated to add
Since getting into space, CAPSTONE, according to NASA, has "experienced communications issues while in contact with the Deep Space Network." The US agency's spokesperson Sarah Frazier continued:
The spacecraft team currently is working to understand the cause and re-establish contact. The team has good trajectory data for the spacecraft based on the first full and second partial ground station pass with the Deep Space Network. If needed, the mission has enough fuel to delay the initial post separation trajectory correction maneuver for several days.
Final update at 2000 UTC, July 6
NASA says it has reestablished communications with CAPSTONE.