Jan 11 2015

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CubeSats included in Mars InSight lander mission (Updated)

To provide a comms relay link between the lander and Earth. The MRO, MAVEN and Odyssey will not be in position to provide relay comms.

The lander will land in one of four possible landing sites within the Elysium Planitia (around 30N, 150E){

Interesting…Why would those orbiters not be able to cover the InSight lander?

Ah…MAVEN is in the Martian equivalent of a Molynia orbit designed to cover high latitudes, so that explains that.

However, the Mars Reconnaissance Orbiter is in a sun-synchronous orbit inclined at 93 degrees, InSight will be in view of MRO at least once a day. Ditto for Mars Odyssey.

Hmmmmm…time for more digging. Why can’t MRO or Odyssey support the InSight lander?

MRO and Odyssey both use the Electra Proximity Payload, which is a frequency-agile operation across UHF band (390–450 MHz) capable of supporting 1 megabit/second data transfer. The InSight lander is largely based on the Phoenix lander, which also used the Electra system (for some reason, I can’t find the specifics on the InSight lander comms suite), so assuming InSight uses Electra and based on its proposed landing latitude, both MRO and Odyssey will be able to support InSight.

I think the answer is buried in the depths of Wikipedia’s MRO telecommunications section, which says:

Two smaller low-gain antennas are also present for lower-rate communication during emergencies and special events, such as launch and Mars Orbit Insertion. These antennas do not have focusing dishes and can transmit and receive from any direction. They are an important backup system to ensure that MRO can always be reached, even if its main antenna is pointed away from the Earth.[2]

Couple that with Gunter’s brief description of the MarCo mission:

MarCO (Mars Cube One) is a two spacecraft mission to accompany the InSight Mars lander to provide communications relay during the landing phase, as the MRO, MAVEN, and Mars Odyssey orbiters will not be in position to receive InSight data.

(Reading comprehension for the win!!) Ah, so the answer is clearly that the CubeSats accompanying InSight will carry the low-gain antennae for command and control of InSight as it begins landing and entering the atmosphere.

OK, this may have seemed obvious to you (especially if you actually pay attention to what is actually written, unlike me), but I had to come to it the long way.

Maybe even more interesting is this last sentence from Gunter’s page: “Depending on remaining fuel, the MarCO craft may continue on to visit a small body.” The MarCO crafts may be the second (and third) vehicles (after DAWN) to orbit one celestial body, leave and then enter orbit into a second celestial body.


Our commenter points out that the MarCO CubeSats won’t actually orbit Mars, just be in position to provide comms during InSight’s landing. They’ll end up in an orbit between Earth and Mars and from there may enter orbit around some nearby target of interest.

Thanks to our commenter, ‘justrandomnoise’!

Permanent link to this article: http://www.newspaceraces.com/2015/01/11/cubesats-included-in-mars-insight-lander-mission/

1 comment

  1. photon

    Clarification: the MarCO cubesats will NOT orbit Mars; they will perform a flyby and be in an orbit that takes them between Earth and Mars.

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