The Grand Tour alignment

Assembled from 64 blocks · 1 evidence · 57 related

1. Story
2. The arrangement of Jupiter, Saturn, Uranus and Neptune that made a single-spacecraft tour of all four possible using successive gravity assists. It is not a straight line — the planets are spread across a wide arc — but a sequence in which each planet is where it needs to be when a spacecraft deflected by the previous one arrives. Because the four orbital periods are long and mutually incommensurable, the configuration recurs only on a timescale usually quoted as about 175 to 176 years; sources differ on the figure because it depends on how tight an alignment is required. The window governed the mission absolutely: the launch dates, the choice of launch vehicle and the decision to fly two spacecraft rather than four all followed from a date that could not be moved.
3. Knowledge
4. Gravity assist
5. Jupiter
6. Saturn
7. Uranus
8. Neptune
9. The Grand Tour alignment
10. Connections
11. Voyager 1
12. Voyager 2
13. Gary Flandro
14. Gravity assist
15. Jupiter
16. Saturn
17. Uranus
18. Neptune
19. Voyager 1
20. Voyager 2
21. Flandro identifies a four-planet gravity-assist opportunity
22. The Grand Tour alignment
23. Voyager 1 closest approach to Jupiter
24. Voyager 2 passes Saturn and continues towards Uranus
25. Voyager 1
26. Voyager 2
27. Io
28. The Grand Tour alignment
29. Voyager 1 closest approach to Jupiter
30. Active volcanism found on Io
31. Voyager 2 closest approach to Jupiter
32. Pioneer 10
33. Pioneer 11
34. Galileo
35. Cassini–Huygens
36. New Horizons
37. Juno
38. Pioneer 10 passes Jupiter — the first spacecraft to reach the outer Solar System
39. Pioneer 11 passes Jupiter, bending north toward Saturn
40. Galileo enters orbit around Jupiter — the first outer-planet orbiter
41. Galileo is flown into Jupiter to end its mission
42. Cassini passes Jupiter for a final speed boost toward Saturn
43. New Horizons takes a gravity assist at Jupiter
44. Juno enters polar orbit around Jupiter
45. Voyager 1
46. Voyager 2
47. Titan
48. The Grand Tour alignment
49. Voyager 1 passes Saturn and Titan, and leaves the plane of the planets
50. Voyager 2 passes Saturn and continues towards Uranus
51. Pioneer 11
52. Cassini–Huygens
53. Pioneer 11 passes Saturn — the first spacecraft to reach it
54. Cassini enters orbit around Saturn
55. Cassini’s Grand Finale — flown into Saturn to end the mission
56. Voyager 2
57. The Grand Tour alignment
58. Voyager 2 reaches Uranus — the only close encounter ever made
59. Voyager 2
60. Triton
61. The Grand Tour alignment
62. Voyager 2 passes Neptune and Triton, ending the planetary programme
63. Evidence
64. The late-1970s alignment of Jupiter, Saturn, Uranus and Neptune permits a single spacecraft to reach all four by successive gravity assists, an opportunity recurring only on a timescale of roughly 175 to 176 years. V55 verification basis: NOT CHECKED IN THIS RUN. The title, journal, volume and year are given from standard citation practice and the search budget was exhausted before they could be confirmed; the 175 versus 176 year figure differs between accounts and is deliberately given as a range. A curator must verify this citation before publication.