I'm working on designing a CubeSat component which does not comply with all of the requirements in the latest CubeSat Design Specification (CDS), namely:

"The ends of the rails on the +/- Z face shall have a minimum surface area of 6.5 mm x 6.5 mm contact area for neighbouring CubeSat rails."

With our current design, that area will have a hole in it so the area will be smaller, so I presume a Deviation Waiver Approval Request (DAR) will have to be submitted.

I wanted to ask if anyone has any experience with how strict launch providers/brokers/integrators/etc. are with CubeSats which don't conform to the CDS? I realise that different companies have different dispensers that allow for slight variations, but it would be nice to meet the P-POD's standards.

I presume it's more of an issue with the dispenser integrator than launch provider, but not fully certain.

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    $\begingroup$ I would contact the dispenser integrator and ask them directly. CubeSats are not as standardized as they were supposed to be because everybody has special needs in their design. Because of this I would assume many dispensers are a bit flexible. Nevertheless you might (probably) loose insurance on your payload in case of the CubeSat not dispensing because of the design not sticking to the standards. $\endgroup$
    – GittingGud
    Commented Jul 4, 2019 at 6:44
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    $\begingroup$ Regarding this specific requirement. The rail ends are a major load path from the launcher to your satellite, especially if your mounted axially on the rocket. Its possible you could compensate by using a stronger material on the rail ends. But all this would need approval from your launch provider. $\endgroup$ Commented Jul 4, 2019 at 9:51
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    $\begingroup$ I'm afraid the only answer to this is "it depends" on the integrator and teh requirement. Integrators other than CalPoly often do NOT follow the CubeSat standard or only follow it loosely. As @GittingGud said - contact your integrator to find out. $\endgroup$
    – Carlos N
    Commented Jul 22, 2019 at 14:15
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    $\begingroup$ Talk to your integrator well in advance, they hate surprises. $\endgroup$
    – Greg
    Commented Dec 14, 2019 at 0:23

1 Answer 1


If you conduct a loads analysis of both your end and the deployer and can prove that you still have adequate factors of safety in your design then getting a waiver should not be terrible. It's not unusual for a few waivers to be considered in a submission, but it varies a lot by dispenser vendor and launch provider in terms of how hard they are to approve. KSC's rideshare office and Planetary Systems Corp were very good to work with on our last mission and helped us through several similar waivers.


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