Table 3 First estimation of high-level mission requirements for GENESIS

001

The GENESIS mission shall be designed to achieve the main mission objective Obj-1, through the co-location in space of the following 4 geodetic techniques: GNSS, VLBI, SLR, DORIS

002

The GENESIS mission should be designed to achieve the main mission objective Obj-2, for operational time and frequency transfer and synchronization

003

The mission shall comply with the space debris mitigation regulations

004

The casualty risk for the mission shall not exceed 1 in 10000 for any re-entry event (controlled or uncontrolled). If the predicted casualty risk for an uncontrolled re-entry exceeds this value, an uncontrolled re-entry is not allowed and a targeted controlled re-entry shall be performed in order not to exceed a risk level of 1 in 10000

005

The mission shall comply with the space debris mitigation requirements in the nominal and also in the failure case

006

The mission operational lifetime shall be at least 3 years, as a minimum, excluding LEOP, commissioning and disposal

007

The GENESIS mission should be designed for a development time of 3 to 4 years

008

The GENESIS mission should target a launch date in 2027

009

Use of high-technical readiness level, demonstrated instruments and payloads shall be preferred, whenever possible

010

Maximum re-use of existing facilities at ESA and ESA Member States

011

The satellite should be launched into an orbit capable to fulfill the mission and payload requirements

012

A small satellite platform should be targeted

013

The satellite platform shall be able to accommodate all the GENESIS payloads associated to the geodetic techniques. Additionally, the platform should host the other enabling subsystems, as needed (and optional payloads as appropriate)

014

The platform nominal lifetime shall be at least 4 years

015

The offset between each payload and the satellite CoM shall be known with accuracy of 1 mm. Offset stability shall remain within 1 mm level during the whole duration of the mission

016

The CoM position should be known with 1 mm accuracy in the satellite reference frame

017

The satellite shall have a Nadir-pointing face for the whole mission duration, with a pointing accuracy less than 1 degree and a pointing stability of 0.1 degree along the whole orbit

018

The satellite platform shall be able to operate at the least 2 geodetic techniques in parallel at all times

019

Attitude determination shall be maintained at all times with accuracy below 0.1 degree

020

The POD will have to be able to determine the orbit with an accuracy better than 1 cm. POD is also affected by optical and thermal material properties (absorption, reflection and such) of the satellite outer surfaces to make an accurate radiation pressure model of the satellite. This has to be taken into account in CDF in particular with respect to impact on costs

021

The S/C shall be able to download a volume of science data as follows: GNSS tracking data (1 Hz) 0.2 GB/day; DORIS tracking data (0.1 Hz) 0.04 GB/day; Active SLR (SLR related, for synchronization between a ground clock linked to a laser station and a clock on board the satellite) 0.05 GB/day; accelerometer 0.002 GB/day

022

To provide the link with current ITRF realizations, the selected orbit shall be accessible by the established global tracking networks of the different techniques

023

VLBI shall be visible for 20 % time from at the least 2 VLBI stations separated by 10000 km

024

The GENESIS Payloads are: GNSS receiver, VLBI transmitter, a DORIS Receiver and a SLR retro-reflector

025

A common time reference for all onboard instruments

026

An accelerometer for measuring the non-gravitational accelerations, contributing to POD should be included