411 REFERENCE · Wiktionary
Pioneer anomaly
Reference material by Wiktionary contributors. This retains its source identity and is not 411 news reporting.
English
Etymology
Named after NASA space probes Pioneer 10 and Pioneer 11.
Noun
~
en US space program space flight The observed deviation from predicted accelerations of the Pioneer 10 and Pioneer 11 spacecraft after they passed about 20 astronomical units on their trajectories out of the Solar System.
Further reading
en eponyms