Solar mission: designed life 4 years, served 17

Source: Solar energy tracker powers down after 17 years

After nearly two decades, the Sun has set for NASA's SOlar Radiation and Climate Experiment (SORCE), a mission that continued and advanced the agency's 40-year record of measuring solar irradiance and studying its influence on Earth's climate.
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SORCE's TSI values were slightly but significantly lower than those measured by previous missions. This was not an error—its Total Irradiance Monitor was ten times more accurate than previous instruments. This improved solar irradiance inputs into the Earth climate and weather models from what was previously available.

"The big surprise with TSI was that the amount of irradiance it measured was 4.6 watts per square meter less than what was expected," said Tom Woods, SORCE's principal investigator and senior research associate at the University of Colorado's Laboratory for Atmospheric and Space Physics (LASP) in Boulder, Colorado. "That started a whole scientific discussion and the development of a new calibration laboratory for TSI instruments. It turned out that the TIM was correct, and all the past irradiance measurements were erroneously high."
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GOOD JOB . . . SOURCE team!

Bob Wilson

 

I had the computer network task to connect the control center in San Diego with the NASA mission network demarcation in Jet Propulsion Labs. The requirements:

• lowest possible cost (it was only going to last 90 days)
• 45 mbs primary control, voice, and science
• 1.5 mbs alternate routing for control, voice, and science
• Four, 4-wire voice circuits at each end
• Plain Old Telephone dial-up line for redundant access to San Diego routers and switch
• JPL campus network fiber circuit between carrier and mission network buildings
• lowest possible cost

My solution installed the smallest possible routers with a pair, of dual, 4-wire audio controllers using a lash-up, voice-over-IP link (a first for any NASA network.) It used Quality of Service queuing so network management, voice and mission control traffic had priority over both the 45 mbs and 1.5 mbs circuits. Any unused bandwidth could be used by general mission data, e-mail, and web access.

After two years, some of the routers had reached end-of-life. So it was re-engineered with independent, 45 mbs network links and modern hardware. Some of the "network security" staff added requirements so they could wire-tap all traffic. Another two years and the NASA Mission voice team switched from 4-wire, audio telephony to native Voice-Over-IP.

I did it first for a fraction of the cost meeting both redundancy and performance specs. I was glad that the two Mars rovers lasted as long as they did and delivered real science about Mars. But this pattern of extending mission life is the unsung heroics of NASA Missions.

Hubble still delivers useful science even though inertial wheels have all but failed. Other science spacecraft often extend until the last bit of station pointing or control systems fail. The record are the Voyager I and II missions that have left our Solar system. The only physical evidence of intelligent life from our planet.

Bob Wilson