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From what I understand at least in the lower orbits you want the least amount of drag possible.

My brain is telling me that a long pole or submarine shape satellite orientated to the direction of travel or direction of solar wind would be best and not a ball at all?

At what point does the extra weight and mass to make a satellite aerodynamic cost more fuel then saved?

Muze
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    Aerodynamics at a pressure of about 1 bar and subsonic speeds may be very different to drag in a nearly perfect vacuum and at hypersonic orbital speed. – Uwe Dec 30 '18 at 18:40
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    @Uwe If you released 2 rubber balloons with a .2psi from the bow of the ISS one shaped as a strait noodle balloon and the other round how much would "nearly" effect each balloon? – Muze Dec 30 '18 at 18:47
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    At theses speed and pressure cross section is all that matter. – Antzi Dec 31 '18 at 08:09
  • Parachutes are intentional extremely non-aerodynamic. A well-designed parachute has a drag coefficient in the lower atmosphere a bit less than 2. In the thermosphere, that same parachute's drag coefficient might increase to 2.4. Aircraft are intentionally extremely aerodynamic. A well-designed aircraft can have a drag coefficient as low as 0.02, a hundredth the parachute's. In the thermosphere, that same aircraft's coefficient of drag will increase to over 2 -- more than that of the parachute in the lower atmosphere. Shape doesn't matter much in space. Nothing is aerodynamic in space. – David Hammen Jan 01 '19 at 04:18
  • @DavidHammen so the space plane below is not in space? – Muze Jan 01 '19 at 04:52
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    That's not a space plane, @Muze. It would have been a flying brick in the atmosphere. And at 250 km altitude, it was barely in space. The primary driver for the shape was the need for a sizable area for non-moving solar panels. – David Hammen Jan 01 '19 at 05:25
  • @DavidHammen I know just messing with you. Happy New year! – Muze Jan 01 '19 at 05:51
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    Some like of low orbit satellite. E.g. Kosmos 954 or nuclear satellite in general. The only motivation to go with nuclear power is to improve aerodynamics. – user3528438 Jan 02 '19 at 06:05
  • This has inspired Technological challenges to sending a high altitude balloon to space and orbit from 50 km? – uhoh Jan 01 '21 at 04:11

1 Answers1

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The only satellite I know of that was shaped to have low drag was GOCE, which orbited at 250 km.

Since it was vital to ensure that the measurements taken are of true gravity and not influenced by any movement of the satellite, this unique five-metre long arrow-shaped satellite had none of the moving parts often seen in other spacecraft. The satellite, together with its instrumentation, actually forms a single composite gravity-measuring device.

The satellite orbited Earth as low as possible to observe the strongest possible gravity-field signal – hence GOCE was designed to skim the edge of Earth's atmosphere at a height of about 250 km. Low fuel consumption meant that its altitude could be lowered to 235 km in 2012.

An electric ion thruster at the back of the satellite continuously generated tiny forces to compensate for any drag that GOCE experienced along its orbit.

The need to fly low and be ultra-stable led to a novel satellite design that minimised air drag and torque and excludes mechanical disturbances. The result was a slim 5 metre-long satellite with a cross sectional area of about 1m2, weighing in at about 1050 kg. The satellite was symmetrical about its horizontal plane and had two winglets that provided additional aerodynamic stability.

GOCE

You can see this places constraints on the satellite's shape: you can't have protruding solar panels, antennas etc. This means it's only done when really necessary; for most purposes it's much cheaper to go to a slightly higher orbit instead.

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