Technique whereby a spacecraft takes angular momentum from a
planet's solar orbit (or a satellite's orbit) to accelerate the
spacecraft, or the reverse.
"They were brave and not so brave, strong and not so
strong, true believers and skeptical doubters. They went to war in
Mustangs, Liberators (below), Dauntlesses; A-1s and F-86s and
B-26s; O-2s and F-100s and UH-1s. They're still going to war in
F-16s, F-18s, H-60s. They hauled trash in C-47s, and today their
grandsons, and granddaughters -- there's a change for you -- haul
trash in C-17s. They taught flying in muscular Stearmans, lithe
T-38s, comical TH-55s.
"They breathed dry oxygen through chapped, cold lips at
29,000 feet, or fetid jungle air through runny noses at treetop
level.
"They were the navigators, bombardiers, gunners, and
guys in back. They were crew chiefs, avionics techs, armorers,
weather guessers.<