In recent years, as APL has shift from a dependency on naval research contracts, the lab has sought to carve out a new role as a growing rival to NASA's Jet Propulsion Laboratory for the design and management of Solar System exploration missions. Most notable among the Lab's recent success was the NEAR asteroid mission to Eros which was by all accounts a stunning success.

Moreover, in these early days as the story of what went wrong from with Contour begins to take shape there are several reasons why APL will face tough questioning as its seeks to recover from the loss of Contour and go on to manage more missions to deep space - not least of which includes a possible mission to Pluto in 2006. Among the many issues facing the investigation panel are three critical points:

• Firstly, is the fact that the probe was out of range of Earth tracking stations when it ignited its STAR-30BP solid motor to boost itself out of Earth orbit making it extremely hard to diagnose the cause of the failure.

• The possibility that the unknown cause of the failure might have been connected with negligence or poor design management and testing by APL.

• And thirdly, the fact that the failure occurred just as APL's "New Horizons" Pluto spacecraft - whose avionics are largely based on Contour - is confronting the key moment of its struggle for last-minute Congressional approval against the wishes of both NASA headquarters and the White House.

Sources connected with APL report that, while the probe's telemetry wasn't monitored during the unsuccessful burn, it was observed by various instruments of the U.S. military (orbiting and/or ground-based). According to these sources the motor's burn appeared normal until 2 or 3 seconds before its scheduled end, at which point a sudden "flare" appeared almost 10 times brighter in the infrared. This meshes well with telescopic observations of Contour's three visible fragments, which appear to be in the solar orbit that would have resulted from a burn cut 3 seconds short.

There seem to be only two possible sources in the craft for such an explosion: a rupture in the STAR motor itself, or an explosion in Contour's own supply of hydrazine fuel for its maneuvering and attitude control thrusters.

The thrusters, however, had been used repeatedly for a long series of maneuvers during the three weeks the craft spent in elongated Earth orbit before the escape burn, and (like Contour's other systems) had worked perfectly.

Moreover, they were not fired during the burn itself - although they would have been used afterward to despin the craft so that it could switch back from spin stabilization to active 3-axis stabilization.

In Contour's design the STAR motor is nestled inside the craft's structure, raising suggestions that - if Contour's thermal design and testing had been seriously flawed - heat generated by the solid motor might have raised the temperature of the main hydrazine tank enough to trigger its ignition or vaporization.

APL sources, have however told SpaceDaily that this possibility had indeed been considered from the very start of design work on the craft - and that tests had shown that the heat pulse from the STAR burn would have taken an hour to spread fully into the craft, and would never have raised the temperature of any part of it by more than 20 degrees Centigrade - not nearly enough to destabilize its hydrazine.

This would seem to indicate that the explosion did indeed occur inside the STAR motor itself. There are, however, two odd features of this.

First, Thiokol's series of STAR motor models, manufactured for decades, are very reliable - the STAR-30BP motor has been used routinely since 1984, with only two failures in 86 missions. Nor do STAR solid motors seem to deteriorate from prolonged exposure to the space environment; one STAR-48 motor worked perfectly after 15 months in space to brake the Magellan spacecraft into orbit around Venus.

Second, it would seem odd that the explosion occurred at the very end of the burn, just when the intense pressure inside the motor was tapering off. However, yhe latter makes more sense on closer examination.

Solid motors have exploded near the end of their burn on several previous space missions - including Syncom 1 (the very first attempt at a geosynchronous comsat) back in February 1963, and the Surveyor 4 lunar soft lander in July 1967 (which lost contact with Earth at just the moment when its accelerometers indicated that the STAR-37 motor, that had served as its main retrorocket, was starting to drop off in thrust less than 2 seconds before the scheduled end of its burn).

The reason is that a solid motor's thrust starts to drop at the time when its solid fuel has been completely consumed back to the motor's chamber wall in many places, leaving many isolated patches of fuel which are supposed to remain bonded firmly to the wall until they are done burning.

But if one breaks loose, it can instantly be blasted into the motor nozzle, plugging it long enough to create an explosive pressure buildup inside the motor.

Given this danger. solid motors are carefully radiographed during assembly to remove the possibility that flaws exist in the glue bonding the solid fuel to the motor wall, but occasionally flaws can slip through.

Another commentator has suggested that, since Contour spent three weeks in Earth orbit, it might have passed several times through Earth's shadow, leading to major changes in the craft's temperature that might have produced repeated tiny contractions and expansions in the STAR motor's metal wall, thus loosening the glue bonding the fuel to it.

However, APL sources have told SpaceDaily that the spacecraft's elongated Earth orbits were deliberately designed from the start so that it would never fly through Earth's shadow at all, since such periods of cold and dark might have harmed the craft's systems in other ways.

If so, then - while the cause of the failure is still far from certain and will obviously require a detailed inquiry - it would seem likely that it was indeed due to sheer bad luck: a slight flaw in that particular STAR motor that slipped past inspection, rather than negligence in the Contour craft's design and testing by APL.

Exploration Horizons Beyond Contour
If so, this would be very good news indeed for New Horizons, whose approval would be seriously endangered by any evidence of APL negligence - especially since, unlike Contour, it would carry 7 kg of highly radioactive plutonium-238 for power.

Complicating matter is that it's unlikely that the official inquiry into the Contour failure can be completed before the House votes on whether to approve the Pluto probe; but there would be nothing to keep Congress from approving initial funds for New Horizons - that could be withdrawn later if the inquiry did actually give cause to doubt the probe's reliability.

It should also be noted that New Horizons differs very significantly in design from Contour. While its avionics are substantially based on Contour; its body shape, and mechanical and thermal structures are radically different in design, and the engineering team that designed it is more closely associated with APL's highly successful NEAR asteroid rendezvous craft.

Any rejection of New Horizons at this very last point because of the Contour failure would be sadly ironic, for virtually all the other news in the last few weeks has been very favorable to the mission.

Moreover, its own STAR-48V kickstage is fastened to the outside of the spacecraft by a bracket - eliminating any conceivable danger that it might generate a heat buildup inside the craft - and will be fired immediately during the initial launch (and then ejected), eliminating any danger that prolonged exposure to the space environment might damage it.

Moreover, the craft will already be travelling at escape velocity from Earth before the STAR motor fires, eliminating any danger that an explosion or failure of the motor might cause the plutonium in its RTG power generator to fall back to Earth.

In any case, rejection of New Horizons at this very last point because of the Contour failure would be sadly ironic, for virtually all the other news in the last few weeks has been very favorable to the mission.

The long-awaited "Decadal Survey Report" commissioned by NASA itself, in which a board of America's top planetary astronomers recommended the form of the Solar System exploration program through 2013 - forcefully described a Pluto-Kuiper Belt Object flyby mission as the highest priority by far for an immediate new project start, and this report played a major role in persuading the Senate to fund New Horizons for a 2006 launch.

Meanwhile, the August 19 edition of "Aviation Week" reports that NASA management is now dropping its initial plan to resist this mission and instead request designs for a later Pluto probe launched in 2008-09.

The latter, having missed its opportunity for a gravity-assist flyby of Jupiter, would require development of a large attached package of solar-powered ion engines adding $150-200 million to the mission's cost, and delaying its arrival at Pluto by five years (greatly raising the chances that Pluto's scientifically important atmosphere would have frozen out by then as the planet moves slowly farther away from the Sun).

According to Aviation Week, "Space science managers at agency headquarters have concluded that the $120 million [added to NASA's budget] in the Senate version of NASA's spending bill for Fiscal 2003 would be enough to keep New Horizons working toward a January 2006 launch, and want to be ready if the House goes along. The funds would support a move into final mission design and selection of a launch vehicle, as well as the environmental impact work that would be required because of the plutonium-charged electric generator the spacecraft would carry."

This would seem to be confirmed by rumors that the Jet Propulsion Laboratory has now decided to endorse the 2006 launch of New Horizons, and last week stopped preliminary work on its own design for the more expensive solar-electric propelled Pluto probe that it would submit if NASA did ask for a new design for the spacecraft. (Lockheed Martin - which collaborated with JPL on the design of the "POSSE" Pluto probe which was New Horizons' chief rival for selection in 2001 - stopped its own work and endorsed New Horizons last March.)

Two other recent developments work in favor of the selection of this mission for a 2006 launch. First, on Wednesday the first flight of the first generation of Atlas 5 boosters - a more powerful version of which is one of the two finalists to launch New Horizons - went flawlessly. (The other finalist is the as-yet untested Delta 4.)

Second, preliminary analysis of data from Pluto's telescopically observed occultation of a star on July 19 now indicates that its atmosphere is indeed rapidly dropping in temperature, further increasing the importance of getting a probe to the planet as quickly as possible in order to observe Pluto's atmosphere before it freezes out completely.

At any rate, the disappearance of Contour has provided one final unexpected chapter to the utterly fantastic "Perils of Pauline" saga of the effort to persuade NASA to fly a Pluto probe, and not until some time next month will we know whether the House will approve or reject New Horizons - or whether, in that case, House-Senate negotiations will lead to its ultimate approval by Congress.

additional report
NASA Appoints Contour Investigation Team
Washington - Aug 26, 2002 - NASA Administrator Sean O'Keefe today announced that Chief Engineer Theron M. Bradley Jr. will lead a team to investigate the apparent loss of the CONTOUR mission space probe. The investigation team will independently examine all aspects of the CONTOUR mission, which has been out of contact with controllers at the Johns Hopkins University Applied Physics Laboratory (APL), Laurel, Md., since a scheduled engine firing Aug. 15.

In May, Bradley joined the agency as Chief Engineer to provide independent technical review of NASA's programs and projects. He's a distinguished U.S. Navy engineer who was instrumental in the initial design of the nuclear propulsion plant for Nimitz class aircraft carriers and the advanced reactor design for Los Angeles class submarines. Bradley also served as a civilian with the U.S. Department of Energy and the Department of Defense in numerous leadership and management positions.

The team will include a team of internal NASA investigators from space science, as well as other aerospace disciplines, and external experts with extensive experience in accident examinations. The group is expected to report its initial findings to NASA Headquarters in six to eight weeks.

Among the team members selected to work with Bradley are retired Navy Admirals J. Paul Reason and Joseph Lopez.

Admiral Reason is a member of NASA's Aerospace Safety Advisory Panel (ASAP). He's an aerospace consultant and former four-star Commander in Chief of the U.S. Navy's Atlantic Fleet. The ASAP was established by Congress in January 1967 after the Apollo 204 Command and Service Module spacecraft fire and is chartered to review, evaluate and advise on agency program activities, systems, procedures and management policies that contribute to risk, and to provide identification and assessment for the NASA Administrator.

Admiral Lopez is one of the two flag officers in the U.S. Navy to achieve the rank of four-star admiral after direct commission from enlisted service. The retired admiral is the former commander of NATO forces in southern Europe and has played a leadership role in numerous accident investigations.

He currently directs Global Government Operations as an executive with Houston-based KBR (Kellogg, Brown & Root).

On Aug. 15, CONTOUR's STAR 30 solid-propellant rocket motor was programmed to ignite at 4:49 a.m. EDT, giving CONTOUR enough boost to escape Earth's orbit. At that time, CONTOUR was about 140 miles above the Indian Ocean and out of radio contact with controllers. The CONTOUR mission operations team at APL expected to regain contact at approximately 5:35 a.m. EDT to confirm the burn, but NASA's Deep Space Network (DSN) antennas did not acquire a signal.

Since then, there has been no contact with CONTOUR. Commands pre-programmed into the spacecraft's flight computer system, designed to instruct the spacecraft to try various alternate methods of contacting Earth when contact is lost, also have not worked to date.

Images from a Spacewatch ground-based telescope at Kitt Peak, Ariz., show three objects at the location where CONTOUR was predicted to be, images which may indicate the spacecraft has broken apart. Mission controllers at APL will continue listening for signals from the spacecraft periodically until early December, when CONTOUR will come into a more favorable angle for receiving a signal from Earth.

CONTOUR is a Discovery-class mission to explore the nucleus of comets. The Principal Investigator is Dr. Joseph Veverka of Cornell University, Ithaca, N.Y., who selected APL to build the spacecraft and manage the mission for NASA.

Contour 2002
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