NASA/JPL-CALTECH PHOTO
Ingenuity is designed to avoid obstacles that can spell
disaster, like large
rocks, when locating a place to land.
fibers placed 45 degrees to the blades’ chords. Te break- through design results in a stiffer blade that resists twisting. Additionally, a 16-degree twist built into the blades allows for easier hovering. Ingenuity’s swashplate is the same as that of a conventional
helicopter. Te cyclic and collective controls are sealed against dust and moved by servos that receive commands from the aircraft’s computer. Te whole shaft is driven by a brushless DC motor in which a ring of magnets revolves around fixed coils, just the opposite of how a standard electric motor runs. “Te arrangement gives Ingenuity’s motor higher torque and greater power with less draw on the battery,” Pipenberg explains. A six-cell lithium-ion battery powers the helicopter, and
about 60% of the electricity is used to keep certain parts of the aircraft warm. A solar panel on top of Ingenuity keeps the battery charged. Some components, such as the servos, can be warmed on command depending on the expected weather, while the avionics box is automatically kept warm at night.
And it all worked better than expected. “Our helicopter
is even more robust than we had hoped,” says Joshua Ravich, Ingenuity’s mechanical engineering lead at NASA’s Jet Propulsion Laboratory (JPL). “Te power system we fretted over for years is providing more than enough energy to keep our heaters going at night and to fly during the day.” Like a hand fitting the right glove, everything about
Ingenuity centered on building the aircraft to fit into the underside of the Perseverance rover. “It’s very tight, and we had to be sure it wouldn’t interfere with the rover’s mission,”
42 ROTOR JUNE 2021
Pipenberg notes. Te landing gear folds up, and a special deployment system developed by Lockheed Martin gently unfolds Ingenuity until it stands upright on the Martian soil. Deployment takes six days.
Anything but Conventional Temperatures on Mars presented a special challenge to maintaining the helicopter. Te planet can get brutally cold at night, with temperatures easily plunging to -130°F, making conventional oils useless. “Tey would just solidify,” says Pipenberg. Ten there’s the mostly carbon dioxide atmosphere. While won’t affect aircraft performance, it does change the
CO2
performance of lubricants, which are crucial to unheated components, such as the landing gear’s leg joints. “Oxidation is slow, water vapor is low, so lubricants act
differently [on Mars],” Pipenberg says. “Graphite [a dry lubricant] becomes extremely abrasive. Other dry lubricants such as molybdenum disulfide work really well on Mars.” Ingenuity’s frame, along with its booms, yokes, trusses,
and fittings, uses the latest unconventional materials to meet the high bar of space travel. “Advanced composites are absolutely required to do a mission like this,” Pipenberg says. Tese exotic and continually evolving materials are mostly
carbon fibers packing up to three times the strength and stiffness of steel and held together with a variety of specially designed resins and tapes. Tey’re rigid as well as inert, meaning they don’t secrete even the most minuscule chem- icals or gases, which are emitted more readily in a vacuumlike space.
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76
