The Mission Of A Lifetime

Nasa Comet Drawings

Despite the interest of scientists and engineers in sending a mission to a comet, by the end of the 1970s no space agency had approved such a project. However, with comet Halley, the most famous and historically important such object, due to reach the perihelion of its 76-year orbit in February 1986 several agencies began to give serious consideration to sending spacecraft to inspect it. Although calculations have accurately traced the orbit of Halley's comet back as far as 1404 B.C., when...

Sun Gate Sensor

The inferred configuration of the ribs of Galileo's high-gain antenna in its partially opened state. 'cold soaks' were performed in July and August 1991, but to no avail, and further efforts were postponed until after Galileo made its flyby of Gaspra on 29 October 1991.175,176 After Gaspra was announced as the target for the first-ever asteroid encounter, astronomers readily compiled a list of everything that was known of it, which was not much, and then set about making further observations....

The Final Soviet Debacle

In the decade after NASA's highly successful Viking missions to Mars, which saw orbiters dispatch landers to the surface, a variety of ambitious follow-up projects were elaborated in the United States, the European Space Agency came close to approving its Kepler Mars orbiter, and the Soviet Union was planning to resume its exploration of the planet with a series of increasingly complex missions.1 In the late 1970s the Soviets decided to start with a mission to explore one of Mars's two moons,...

But Now Giotto Has The Shout

Surveyor Spacecraft

While the Soviet Vega probes were approaching their first target, Venus, the other three spacecraft of the international Halley armada were being prepared for launch. The first off would be Japan's MS-T5 'precursor' probe. The role of the Japanese spacecraft in the armada was to provide preliminary estimates of the comet's water production rates, to study jets and outbursts activity, and to monitor the state of the solar wind during the other encounters. The twin spacecraft were integrated...

Comet Frenzy

Capsule Reentry

After the international armada of spacecraft provided exceptional and unexpected results at Halley which indirectly showed just how little we knew about comets, the various space agencies proposed a variety of new and more complex missions to comets. There were four major themes (1) spacecraft which were to investigate a number of nuclei in order to establish a statistical database of their characteristics (2) spacecraft to collect samples of dust and gas from the coma and return this to Earth...

Balloons To Venus

In late 1984, after 4 years of development, the two Vega spacecraft were ready, but it was a close result because the Soviets apparently underestimated the complexity of the mission and its management so much so that at one point it was thought that they might miss the launch window for Venus, in which case they would have to be stripped of their atmospheric capsules and be launched directly towards Halley in the same window as Giotto and Planet-A in mid-198 5.152 A Proton, the standard Soviet...

The Rise Of The Vermin

The first asteroid was discovered on 1 January 1801. Others discoveries followed, and soon there were so many that astronomers dismissed them as ''vermin of the sky''. The possibility of sending spacecraft to asteroids (or 'minor planets' as they are more properly known) was discussed in the United States in the 1960s. In its 1966 Planetary Flight Handbook NASA even published trajectory data for flights to (1) Ceres and (4) Vesta, which are two of the largest.371 Likewise, ESRO studied the...

Europe Tries Harder

The Europeans started to formulate proposals for deep-space missions in the early-1960s, but none were undertaken. One reason was that until the introduction of the Ariane launcher in 1979, Europe had to use American rockets. Another reason was that space scientists in Europe were primarily interested in astrophysics, the fields and particles in space and solar physics, and so had little interest in exploring the solar system. This focus is illustrated by the fact that although the...

Mapping Hell

Orbiter Structural Spares

Immediately after VOIR was canceled, JPL engineers and the scientists involved in Venus radar astronomy set out to investigate how the scientific objectives might be recovered by a less costly mission that would be more politically acceptable. It was estimated that the cost could be halved by deleting all of the instruments apart from the radar, reusing as much hardware as possible and simplifying the mission. The revised proposal became known as the Venus Radar Mapper (VRM). The cost-saving...

X

Rocket Trajectory

The structurally identical Planet-A (Suisei) and MS-T5 (Sakigake) spacecraft which Japan launched on Halley flyby missions. (JAXA) Communications were by low- and medium-gain antennas, or by a despun 80-cm mesh antenna capable of data rates of up to 64 bps. The total height of each probe, including its antennas, was about 2.5 meters. To reduce the spacecraft's mass to fit the launch vehicle's performance, carbon composites and lightweight aluminum honeycomb were used extensively for the...

Mirror Tilt Motor

Soviet Balloon Mission Vega

The Halley Multicolor Camera of the Giotto spacecraft. Note the mirror set at an angle of 45 degrees and the baffle that was eventually shattered by dust impacts. (ESA) beaten a similar French-JPL proposal). By 1983, however, the development of the camera was impaired by a severe financial crisis, and it became evident that unless the budget was increased Giotto would have to fly without its main instrument In fact, the development was further impaired by technical problems and the camera was...