So we won’t be littering Mercury for at least another year. Darn.
But the thing survived launch, went through years of space, and has been baked by the sun and Mercury for 1000 days. Not too shabby.
The effort that went into just the thermal for our one little instrument out of an entire payload suite was loco – thermal modeling, slip interfaces, heat sinking, material selection, deliberate choice of surface emissivity, MLI to protect against heat and cold… Crazy. Then there is the electrical shielding, high voltage management, and connection integrity between the stacking electronics modules. Mechanical tolerancing and fastener fussiness, constraint without over constraint, surface finishes, lightweighting (tracking of a mass budget where grams of material count), knowledge of moments and center of mass… Material selection, outgassing considerations, venting, etchants, staking, arcing control, windings, tensioning and torques… Vibe modeling, FEA models of stresses, acoustic testing, assembly, documentation, parts drawings for hundreds of parts, certifications, vendor consultations, reworks and redesigns, tracking. Techs to build engineer and greybeard insanities. GSE to be built. Meetings and consultants… I know I am leaving some stuff out.
And that happens for every system with a huge payload suite of instruments, a spacecraft system, communications, gnc, propulsion, thermal…
MESSENGER Celebrates 1,000 Earth Days in Orbit around Mercury
Later today, the MESSENGER spacecraft will have completed 1,000 Earth days of flight operations in orbit around Mercury. “This milestone is a testament to the outstanding work of those who designed, tested, and operated this spacecraft,” says Jim McAdams of the Johns Hopkins University Applied Physics Laboratory (APL) and the lead engineer for MESSENGER’s mission design team.
“MESSENGER was designed to function for eight years following launch and to withstand the harsh environmental conditions of the inner solar system and solar heating up to 11 times greater than experienced by spacecraft near Earth,” McAdams says. “The probe not only has continued to function, it has thrived, with very little loss of planned observations for more than nine years and four months since launch.”
“To date, the spacecraft has returned 198,166 images from orbit about Mercury, far exceeding the mission’s original plans,” says APL’s Rob Gold, MESSENGER’s Science Payload Manager. “In the original mission concept we were planning to use half of the telemetry for images and the rest for the other instruments, and that plan would have returned about 1,000 images of the surface of Mercury. That we are now approaching 200,000 images is the result of major technological improvements made during construction of MESSENGER.”