It is normal for satellites to have solar panels on both sides of the body.

But Landsat satellites, from Landsat 4, seems to have the solar panel on only one side. Are there any specific advantages of having such a configuration?

Landsat satellite series from wikipedia


Solar panel technology seems to have caught up with power requirements on the satellite. Since price of components is really no object when building a system like this, super expensive panels with efficiency ratings of up to 40% can be used.

The trick to engineering something properly is using just the right amount of materials, as the old maxim goes "Any idiot can build a bridge that stands, but it takes an engineer to build a bridge that barely stands". If the engineers were meeting the power requirements for the satellite with just one set of solar panels, why include the other? It's possible to predict the power requirements very exactly and each gram that the engineers save can be used on something else which is more mission critical such as a better imagery system.

As to why build it asymmetrically? There are basically no benefits to building it symmetrically. Modern control software can easily compensate for the shifted center of mass and you also save on motors and unfolding systems in mass.

  • $\begingroup$ Still the answer is pending a solid argument for an asymmetric build. $\endgroup$ – karthikeyan Feb 11 at 12:07
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    $\begingroup$ There's no reason for a satellite to be symmetrical. Symmetrical designs are often used for aesthetics, aerodynamics, or balance, none of which a satellite needs to have. In the satellite's case, form follows function so they design the functionality and this causes the shape, they don't start out with a 'satellite shape' and then fill in components. In this case, building the solar panels symmetrically would have just increased the weight as you need more motors to unfold the panels. $\endgroup$ – Dragongeek Feb 11 at 12:36
  • $\begingroup$ I anticipated some form of payload packaging efficiency given the satellite in discussion is earth observation satellite, but your argument for more motor is also a good one. Didn’t strike me nor have I come across. Thanks. $\endgroup$ – karthikeyan Feb 11 at 12:51
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    $\begingroup$ @Dragongeek isn't there asymmetry in solar radiation pressure causing an unbalanced torque? or does it just integrate out over an orbit? $\endgroup$ – costrom Feb 11 at 17:40

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