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  • STMSat-1 Youngsters Told: “Only Half of the CubeSats Deployed into Space Work”

    From ARRL de WD1CKS@VERT/WLARB to QST on Thu Jun 16 18:02:06 2016
    06/16/2016

    A month after deployment of the STMSat-1[1] CubeSat from the International Space Station (ISS), prospects are dimming that the little spacecraft will ever be heard from. Outside of a weak signal that could have been STMSat-1, nothing has been received from the little CubeSat - built by students at St Thomas More Cathedral School in Arlington, Virginia - since it was placed into orbit on May 16. STMSat-1 Education Manager Emily Stocker said that NASA engineer Joe Pellegrino, who is STMSat-1's mission manager, addressed an assembly at the school on June 14.

    "The assembly we held was specifically to update the students on the status [of STMSat-1] before they leave for summer vacation," Stocker told ARRL. "The feeling at the school is still hopeful, but cautiously so, as we have not yet heard from it." STMSat-1 is supposed to transmit on 437.800 MHz FM and send slow-scan television (SSTV) pictures back to Earth.

    "From the beginning, our mission was to inspire grade-school students - and anyone else - to pursue STEM careers and pique that interest," Stocker said. "We have accomplished that mission. While a [SSTV] picture would be nice, that is simply the icing on the cake."

    When a signal from STMSat-1 failed to show up after the CubeSat's release into orbit, some speculation centered on a malfunction of the antenna deployment mechanism, which called for a heated blade to burn through fishing line securing the antennas. Stocker said that, according to the antenna manufacturer, the antennas should have deployed by now, regardless of the mechanism, since the fishing line would already have disintegrated due to the harsh conditions in space.

    In his presentation[2] to the students, Pellegrino stressed that space missions are challenging. He pointed out that the environment of space is very extreme, and that it's "very difficult to build machines that work in this environment."

    "Only half of the CubeSats deployed into space work," he noted. "NASA is a large organization, with thousands of smart people, and their spacecraft still fail sometimes." As an example, he recalled the October 2014 Antares launch failure, in which a couple of CubeSats built by university students were lost.

    STMSat-1 was rebooted from the ground on May 24 in an effort to turn on its transmitter. NASA's 21-meter dish at the Morehead State University Space Science in Kentucky has continued to scan multiple frequencies for the spacecraft's signal.

    Stocker said in late May that Morehead University "picked up something within our frequency range," but that it was unclear if the signal came from the school's CubeSat or from another one deployed from the ISS at the same time as STMSat-1. JA0CAW posted a tweet reporting a signal heard on 437.800 MHz at 1225 UTC on May 25.

    Pupils at the school built STMSat-1 during a 4-year-long project, and the satellite was launched to the ISS last December. St Thomas More pupils will continue to track the altitude of the spacecraft on a daily basis to determine when it will re-enter Earth's atmosphere. In the meantime, they will perform a cause-and-effect analysis using a fishbone diagram, which Pellegrino explained during his visit to the school.

    Stocker said students were encouraged to think about the fishbone diagram over the summer as well as to track the altitude of STMSat-1 to accurately predict when to watch for its re-entry into Earth's atmosphere. When school resumes in the fall, "we will collect all thoughts about the fishbone diagram and do what rocket scientists do while we analyze the results and share that with the community," she added. She invited all STMSat-1 Remote Mission Operating Centers (RMOCs) to send in fishbone diagrams.

    The satellite is the first to be designed and built by grade schoolers, who have been supported along the way by NASA technical advisors and local radio amateurs. NASA's Technology Demonstration Office provided the school with a mobile "clean room" for the construction and a ground-station antenna.

    "The students think it is the coolest thing in the world that this mission ends as a 'shooting star' - and they plan to make a wish," she said. "They - and we - knew from the beginning that the mission would only last up to 9 months post deployment from ISS, so this was not news for them." 


    [1] http://www.stmsat-1.org/
    [2] https://drive.google.com/file/d/0B1wUmAxZJJoMUElNLWQyYktCcHc/view

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