This Week in Rocket History, we look at the CONTOUR spacecraft that promised much but never actually got to fulfill its potential.

CONTOUR was the sixth in NASA’s Discovery Program, a medium-cost and medium goals program that has spawned missions from Mars Pathfinder to Dawn and InSight. CONTOUR or COmet Nucleus TOUR was designed to fly through the tails of at least two comets, including Comet 73P/Schwassmann–Wachmann, which produced the Tau Herculid meteor shower earlier this year, and Comet 2P/Encke, which we talked about in a What’s Up segment a couple of months ago. CONTOUR’s primary mission was expected to last until June 2006, with a possible third target, Comet 6P/d’Arrest, leading to a 2008 mission extension.

The spacecraft design was simple and had very few moving parts except for one science platform. The antenna was a passive omnidirectional design. These design choices reduced costs and made the spacecraft more reliable, at the cost of being able to send back less data.

The spacecraft had a multi-layer Kevlar and metal Whipple shield since it would be intentionally sent into the high debris environment of a comet’s nucleus.

Just over 30 kilograms of the spacecraft’s 970-kilogram mass was science instruments. The CONTOUR Remote Imager/Spectrograph, or CRISP, was a 1000-by-1000 pixel sensor sensitive to light between 450 and 770 nanometers. The spacecraft also had a spectrograph, sensitive to longer wavelengths of light but at a much lower resolution of 256-by-256 pixels in color and spectra. This would have produced 100 meters per pixel resolution color images of each of these comet nuclei and also measured their spectra as CONTOUR passed within 100 kilometers of them.

Other instruments included the Comet Impact Dust Analyzer and the Neutral Gas Ion Mass Spectrometer, which would have worked together to measure the comets’ chemistry by measuring the number of different isotopes of elements in the comets’ comas. Dust impact data would have completed the picture and allowed different comets to be compared for the first time.

CONTOUR was launched on a Delta II 7425-9.5 on July 3, 2002, at 06:47 UTC, from Cape Canaveral Air Force Station. The rocket had four solid rocket boosters and used a Star-48 third stage, with a 9.5-foot diameter fairing. The 9.5-foot fairing is the classic shape used on all of the GPS II launches on Delta IIs, and also many other iconic science missions like the Spirit and Opportunity Mars rovers.

The Delta II lifted CONTOUR into a high apogee Earth orbit, where it was to perform further 23 maneuvers over 43 days to line itself up for the comet rendezvous.

The first major operation came six weeks after launch when CONTOUR fired its solid motor to leave Earth orbit at perigee. The burn was to set up an Earth flyby before visiting Comet Encke. After visiting Encke, it would have done two more Earth flybys before visiting Comet 73P. However, something happened to the motor, and contact with CONTOUR was never re-established. Later, radar tracking detected several pieces of debris in the expected area of the spacecraft. NASA attempted to contact the spacecraft until December 2002, when the mission was declared lost.

An investigation concluded that the spacecraft likely suffered a structural failure during the burn, either due to a malfunction with the motor itself or a design flaw. Another possible cause was the spacecraft having lost guidance during the burn.

You can find a link to the full report in the show notes on DailySpace.org.

More Information

CONTOUR (NASA)

Contour (Comet Nucleus Tour) (Aerospace Technology)

Contour Mishap Board Completes Investigation (NASA via Web Archive)