1. Figure 10 shows the time profile of the propellant consumption. The scattered line indicates the remaining propellant weight calculated from temperature and pressure of the propellant tank. The bold line represents it calculated from operation profile of the gas regulation valves. The both lines are self-consistent with each other within their accuracy. Figure 10 describes the operation chronology of IES because the propellant consumption is directly proportional to ΔV of the HAYABUSA spacecraft. The continuous acceleration was started from July after the test operation on June. At the beginning of August various tests on the orbit determination requested a pause of the IES operation. The largest solar flare on the record broke out at the end of October, when HAYABUSA kept a safe mode without the IES firing. In three weeks at the season of the year-end and the new year the IES was suspended depending on the plan of the orbit maneuver. Almost all the ΔV by IES has been completed by the end of February 2004. And the IES firing was executed in order to adjust the orbit on March so that the propellant was consumedata slowrate.
2. The ΔV maneuver by IES over 10,000 hour&unit has concreted to encounter with Earth. The orbit of HAYABUSA in the rotational coordinate system is seen in Fig.11, where Earth is fixed at the original point and Sun on the negative horizontal axis. Figure 11 shows the relative location of HAYABUSA against Earth. Though just after the launch the extrapolated orbit never reaches Earth, it changes gradually in accompany with the IES maneuver. HAYABUSA will arrive at Earth on May 19, 2004 and bend the relative velocity vector toward the asteroid ITOKAWA bymeansof theEarth swing-by. Fig.10 Profileofthe propellantconsumption. Fig.11 Orbit of HAYABUSAin rotational coordinatesystem.
3. Fig.12 Turn-on sequence. DataonJuly 3,2003.