NASA is sending two cubesats to Mars!

[Frida Space]

The Mars Cube One (MarCO) cubesats will hitch a ride on NASA's InSight lander, which will launch to Mars next year. The two 6U cubesats will provide communications for InSight during its landing phase, as MRO, MAVEN and Odyssey will all be unavailable at the time of landing. Depending on remaining fuel, the two MarCO probes might continue on to visit a small body.

NASA hasn't made available an official press release yet, but, according to rumors, the two cubesats might have a few instruments on them too.

Will these be the first interplanetary Cubesats? I can't remember whether or not there have been others before. Thanks!

[Kryten]

Will these be the first interplanetary Cubesats? I can't remember whether or not there have been others before. Thanks!

Small sats have made interplanetary missons before (e.g. the 20kg Shin'en venus flyby craft), but this would be the first built to the cubesat standard.

[NERVAfan]

When did 6U cubesats become a thing anyway? I saw them mentioned as secondaries on some other mission... I thought there were only 1U, 2U, 3U.

[Tommygun]

When did 6U cubesats become a thing anyway? I saw them mentioned as secondaries on some other mission... I thought there were only 1U, 2U, 3U.

They have even more than those, I have read about 12U and 27U as well:

https://directory.eoportal.org/web/eoportal/satellite-missions/c-missions/cubesat-deployer

[Kryten]

When did 6U cubesats become a thing anyway? I saw them mentioned as secondaries on some other mission... I thought there were only 1U, 2U, 3U.

Up to 3U is the standard size for the cubesat deployment system (PPOD), but in practice was found to be too small for real technology missions. Larger ones require specialised deployment systems, but are still easier to design and integrate.

[Frida Space]

So, today MRO will fire its six 22N-thrusters for 77 seconds to be able to hear InSight during its landing on Sept. 28, 2016. However, from what I understand MRO won't be able to transmit the descent data back to Earth immediately, so the MarCO cubesats' purpose still stands. Also, what shocks me is that even after this burn and two even larger ones planned for 09/2016 and 04/2017 which will re-establish its original orbit (lasting >3 minutes each!), MRO will still have 187 kg of hydrazine -- 19 years of fuel! I find this mindblowing. They really packed a huge lot of propellant in there, and also RL thrusters are much more efficient than KSP ones.

www.nasa.gov/jpl/mro/nasa-mars-orbiter-preparing-for-mars-landers-2016-arrival