No. 153 - Orbit determination and spacecraft reconfiguration
21 March 2011 14:00
Report for the period 19 February to 4 March 2011
This report covers 14 days of Rosetta mission operations. The main activities were delta differential one-way ranging (DDOR) to determine the outcome of the burns performed during the previous reporting periods as part of the first rendezvous manoeuvre (RDVM#1) and reconfiguration of the spacecraft upon completion of the manoeuvre.
Orbit determination following the set of burns for RDVM# 1 has revealed that the manoeuvre was almost perfect and any correction would have required a Trim 2 burn with a ΔV of a few millimetres per second – well below the threshold where a correction is considered necessary. With this manoeuvre completed, the spacecraft is now on a fly-by trajectory for Comet 67/P Churyumov-Gerasimenko with a miss-distance of about 50,000 kilometres. After the completion of the RDVM#1 activities the spacecraft has been changed back to its normal configuration and is ready to complete pre-hibernation activities.
During the reporting period, mission operations were conducted using the ESA New Norcia (NNO) and Cebreros (CEB) ground stations and the DSS 14 (Goldstone, 70 metres), DSS 24 (Goldstone, 34 metres), DSS 25 (Goldstone, 34 metres), DSS 26 (Goldstone, 34 metres), DSS 34 (Canberra, 34 metres), DSS 45 (Canberra, 34 metres), DSS 54 (Madrid, 34 metres), and DSS 55 (Madrid, 34 metres) NASA Deep Space Network (DSN) antennas.
At the end of the reporting period on 4 March, Rosetta was 533.2 million kilometres from Earth (3.56 AU); one-way signal travel time was 1779 seconds (29 minutes 39 seconds). The distance from the Sun was 610.3 million kilometres (4.08 AU).
Activities linked to RDVM#1 are now complete, with the flight plans now focussing on the remaining payload activities to be completed by the end of March. The spacecraft will then be ready for the opposition phase in April and May.
Summary of upcoming events: