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A First: CubeSat-Style Probes To Accompany InSight Mars Lander

Posted by timothy on from the emergent-order dept.

Hundreds of CubeSats have been launched to Earth orbit since 2003. Now, though, two of the small-form-factor craft are set for a deeper space mission. According to Spaceflight Now, The twin CubeSat mission, known as Mars Cube One, will launch on an Atlas 5 rocket in March 2016 with NASA’s InSight lander. The CubeSats will relay status signals from InSight as the landing probe descends through the atmosphere, eliminating potential delays in verifying the success of the mission. ... Each Mars Cube One, or MarCO, CubeSat spacecraft measures 14.4 inches (36.6 centimeters) by 9.5 inches (24.3 centimeters) by 4.6 inches (11.8 centimeters) when closed up for launch, according to the Jet Propulsion Laboratory, which announced details of the mission Friday. The standardized and small CubeSat has made satellite design and launching accessible to schools and others; going to Mars costs a lot more (in this case it's a "$13 million secondary mission"), but it could conceivably put interplanetary probes possible for deep-pocketed universities or corporations.

22 comments

  1. CUBEsat? by Ion+Berkley · · Score: 3, Insightful

    You know most peoples definition of a Cubesat is ....a cube shaped satellite, ie all 3 axises have the same length.....now admittedly there are 2U and 3U variants i.e. 2 and 3 stacked cubes.

    This is a micro-satellite, not a cubesat

    1. Re:CUBEsat? by Anonymous Coward · · Score: 0

      You know most peoples definition of a Cubesat is

      PEOPLE'S. Jesus Christ.

    2. Re:CUBEsat? by Brett+Buck · · Score: 2

      That's a pretty minor distinction. I was an industry advisor for what might have been the first 3-high cubesat. The only important restriction is that it fit in the ejection canister.

            The basic single 4.5" cubical satellite is *very limited* in capability due to lack of any viable attitude control and very low power available. It's tough to do anything useful even in low Earth orbit. That would be crippling for an interplanetary mission.

            I expect someone may have worked out the numbers, but for a Mars relay you have more-or-less no attitude control and need a fair bit of power for at least several hours. It's going to take a pretty big battery+an decent array to run rad-hard electronics for any length of time. None of this "guts of a FRS radio" telemetry stuff, that will fry very quickly beyond the Van Allen belts. Also, no or inconsequential albedo heating, so it will need big heaters to keep going for any length of time.

               

    3. Re:CUBEsat? by radarskiy · · Score: 3, Interesting

      The *actual* definition of a CubeSat is a satellite built in multiples of a 1 L unit that is compatible with an OPAL microsatellite used as a launcher. MarCO meets the specifications for a 6U CubeSat.

      MarCO itself is not large enough to meet the specifications of a microsatellite.

    4. Re:CUBEsat? by Anonymous Coward · · Score: 0

      It seems most people's definition of a cubesat, including yours, is wrong. Mostly this is attributable to the large volume of bullshit people can accumulate even as they dispense it as fast as possible. Way to shoot your mouth off. Don't try and think your way out of this problem, run for congress instead. Or you could become a manager.

    5. Re:CUBEsat? by Anonymous Coward · · Score: 0

      That's not a definition, that's a specification. I prefer Nixon's appoach. "Well, David, it means whatever i choose it to mean." rather than the Clinton version of "it depends on your defintion what is is."

    6. Re:CUBEsat? by Anonymous Coward · · Score: 0

      As noted elsewhere, CubeSat is the name given to satellites based on a 10x10x10 cm cube, referred to as a "U", a 10x10x10 satellite would be a 1U (and are quite rare). Most cubesats these days are 2U or 3U (10x10x20 and 10x10x30, respectively). As also noted elsewhere what really means is that it can fit in a p-pod dispenser or similar. There are a lot of 6U satellites being built: they're more like 10x20x30. And there's an assumption that 1U = 1kg

      In general, these are referred to as "nano-satellites" as opposed to "small satellites" or "micro-satellites". There's actually a fair amount of dispute about coming up with a generalized naming convention, mostly because nanosats have a greatly reduced regulatory oversight stemming from their origins as low budget student projects. Defining what is a "nano" vs "small real satellite needing full regulation" is a contentious issue because "traditional big space" is getting into the tiny satellite business. Things like orbital debris and radio licensing are the sticky ones. A university can license their satellite radio as an amateur radio station; but the same is not true if Google wants to launch 1000 little flying cameras.

      Most people I work with in the space biz make the distinction somewhere between 10-100 kg: something less than 10kg or 10U is a nano-satellite. something on the 30x30x30 cm size (27U) is probably a microsatellite or small satellite.

      And then you get into important distinctions such as "propulsion", where the regulatory regime gets really interesting. It's one thing to put a "flying rock" into orbit in LEO at 400km where it will eventually come down because of air drag and you can figure out where it is by applying laws of physics. It's another to put a self propelled widget in higher orbit, say, at 1000km, where it can be moved around.

    7. Re:CUBEsat? by necro81 · · Score: 1

      I expect someone may have worked out the numbers, but for a Mars relay you have more-or-less no attitude control and need a fair bit of power for at least several hours

      The article mentions that the MarCO sats will have cold-gas thrusters for course correction and attitude adjustment. There are also a set of three reaction wheels for fine attitude adjustment. I expect the attitude adjustment is for optimal solar panel alignment during the cruise, then for radio alignment during the InSight landing.

      (On the other hand, the article says that the MarCO satellites will communicate via X-Band radio to the 70-m receivers in the deep space network. From the picture I don't see anything like a convention "dish" high-gain antenna, so perhaps the radio alignment needs are not terribly stringent)

    8. Re:CUBEsat? by Anonymous Coward · · Score: 0

      You know most peoples definition of a Cubesat is

      PEOPLE'S.

      Jesus Christ.

      You attempt to clear up an imaginary (misspelled) word by conjuring up an imaginary character?

      Holy Shit.

    9. Re:CUBEsat? by Anonymous Coward · · Score: 0

      Most people's definition of "soft reboot" is pressing the power button gently so I'm not sure what your point is.

    10. Re:CUBEsat? by Coren22 · · Score: 1

      Holy shit was what happened when Jesus visited the privys.

      --
      APK likes to ask for responses to the same things over and over. Maybe he just likes the responses?
    11. Re:CUBEsat? by Anonymous Coward · · Score: 0

      How was it an imaginary word? It was right there in the post. He fixed the possessive. Are you stupid?

  2. Hooray litter on Mars by Anonymous Coward · · Score: 0

    We've fucked up our planet, now let's fuck up the rest!

    1. Re:Hooray litter on Mars by Anonymous Coward · · Score: 0

      Exactly! The Species (tm) must colonize the rest of the universe because, like, we totally can, and we must preserve this glorious Species (tm)!!!

      Even though I can't even be bothered to talk to my neighbors I feel the Species (tm) is the most important thing in the universe.

  3. mars radios and satellites by Anonymous Coward · · Score: 0

    Actually, if you make it shiny metal so the A/E ratio is right, it will stay nice and toasty warm at Mars: no heaters required. While the solar panels don't have the right ratio (they will tend to be cool), the energy that falls on them is converted to heat ultimately.

    The radiation requirement isn't all that bad: typical Mars missions are a few kRad/year, and MarCO only has to run for a few hours. A lot of the TID issues only arise when power is on and there's bias on the circuitry, so passing through the VA Belts isn't a big deal.

    Link budget-wise, there's been some papers at the Logan small satellite conference that go into this in more detail, but a couple watts into a not very high gain antenna might do it, since you've got a big 70m antenna with 60-70 dB gain and a cryogenic receiver at the receiving end. Mars would be less than 1 AU away at arrival time (3-4 months after closest approach, when it's 1/2 AU away). That's about 270 dB of free space path loss between isotropes at 8.5 GHz. +30dBm EIRP and 70 dB Rx antenna means -170dBm into the receiver; before you consider system temp at Rx and antenna gain on the Tx end. at room temp, kTB is -174 dBm/Hz. You're not going to get megabits/second through, but the link will close.