4.1 Mission Events Sequence

A schematic of Asterius' mission is found in Figures 1 and 2. Figure 1 covers the mission up to and including the insertion into Europa's orbit. Figure 2 covers the mission after insertion.

Asterius will embark on its journey to Europa aboard a Titan IV/Centaur launch vehicle. The Titan requires that launch preparations begin 33 months prior to the actual launch date. The mission is slated for launch on March 23, 2004 from Cape Canaveral Air Force Station. Therefore, launch precedings will ensue by August of 2001.

The Titan IV will deliver Asterius into a geosynchronous transfer orbit (GTO), whereupon the Centaur upper stage will fire, propelling Asterius on the first leg of its trajectory. The upper stage will be discarded. After Earth escape, Asterius will advance to Mars where it will perform a gravity assist maneuver about the planet, which will catapult the vehicle out of the inner solar system and on to Jupiter.

Asterius will arrive at Jupiter February 23, 2009, after a trip time of about 5 years. The main engines of the spacecraft will fire, slowing Asterius to allow orbit capture about Jupiter. The initial orbit around Jupiter is highly eccentric. Apojove will be reduced by a number of gravity assist slowdowns around the Jovian moons. Finally, Asterius will insert itself into orbit about Europa.

As it orbits Jupiter, Asterius will remotely study Europa, as well as other subjects of scientific opportunity, such as Jupiter and its moons. After it enters orbit about Europa, it will scan Europa's surface, mapping the ice thickness of at least 2/3 of Europa's surface. The map, in combination with Galileo data, will reveal the thinnest spots of Europa's crust, one of which will be selected as the landing site. Asterius will first jettison the Orbital Operations Module (its braking rocket system), then initiate a transfer to the surface, and then execute a soft landing.

On Europa's surface, Asterius will photograph the landing site with EuropaCam, the visible light/infrared/ultraviolet camera. Asterius will analyze the landing site with instruments such as the acoustic sensors. Asterius will deploy the Water/Ice Scientific Probe (WISP) to melt though the ice, studying Europa from a slightly different point of view. During its descent, the WISP will communicate scientific data back to the lander acoustically. When it reaches the water-ice interface, the WISP will discharge an inflatable buoyancy device to stabilize its orientation in the liquid water. The WISP will relay data of the water back to the SOM for a minimum of six hours after reaching the water/ice interface.

Asterius will transmit data for at least one year after landing. After that, it may continue on an extended mission, especially if the WISP will have yet to reach the water/ice interface.

  

Figure 1: Schematic of the Orbital Phase of Asterius' Mission

  

Figure 2: Schematic of the Landing Phase of Asterius' Mission, Including Surface Scanning