This announcement of opportunity addresses the technical challenge of operating a number of CubeSats together or individually in interplanetary space in support of the objectives of a proposed ESA mission - the Asteroid Impact Mission (AIM) - currently undergoing a Phase A/B1 system study. As part of the Asteroid Impact Deflection Assessment (AIDA) initiative, AIM will conduct in-situ measurements of the deflection of the binary asteroid 65803 Didymos caused by the impact of Nasa's DART spacecraft.
AIM has three different mission objectives: Firstly it shall serve as a technology flight demonstrator in interplanetary space, secondly it shall enable the investigation of Near-Earth Object (NEO) mitigation techniques and finally, it shall gain new insights on the solar system evolution.
The current AO therefore aims to investigate concepts which take advantage of exploiting distributed networked or single CubeSat systems in order to provide significant contributions to the ESA Asteroid Impactor Mission asteroid research and mitigation assessment objectives. Any concepts may be proposed to the challenge provided they clearly demonstrate a benefit to the AIM asteroid research and mitigation assessment objectives, comply with the nano-satellite constraints, and address the system level issues defined in this challenge description.
COPINS Operating concept
COPINS consists of a set of 2 CubeSat dispensers with capacity for 3U each and the associated CubeSats that could be deployed and operated as a network of sensors or as separate experiments relevant to the AIM scientific and asteroid mitigation objectives.
The launch of the AIM spacecraft would be in 2020 on the Soyuz-Fregat launcher from Kourou into a direct escape trajectory and would arrive at the asteroid after an approximately 22 month transfer phase. During the rendezvous phase, the distance to the Sun and Earth is close to 1 AU and from 0.5 to 0.1 AU respectively.
After an initial measurement phase, the AIM spacecraft would be manoeuvred to within 10 km of the binary asteroid. Before DART´s impact, the COPINS CubeSats would be released, and the main spacecraft would then retreat to a distance of 100 km away, ready for the impact event no more than one month later. The CubeSats would perform their mission up until 2 months after the impact date, i.e. for 3 months in total, using an inter-satellite link with the main spacecraft's communications system for telecommand, housekeeping and payload telemetry data relay with the ESA ground station network.
Operating CubeSats in interplanetary space in the vicinity of an asteroid puts severe demands on system performance such as radiation survivability of commercial-off-the-shelf electronics, on-board autonomy, guidance navigation and control, communications and propulsion.
The nano-satellites to be considered in the study shall be constrained to:
- Form factor: CubeSat standard
- Total volume: two 3U CubeSat deployers are embarked on the main AIM spacecraft, giving a total of 6 units (litres) of internal volume available to accommodate all CubeSats in the COPINS payload
- Total Mass: up to 9 kg are allocated for all CubeSats in the COPINS payload
- Size: up to 3U for each CubeSat
- Design lifetime: storage (non-operational) during interplanetary cruise plus minimum 3 months in the interplanetary environment at the asteroid
- Inter-satellite link: S-band ISL unit and antenna(s) shall be provided by ESA as Customer Furnished Item and carried on each CubeSat with the following characteristics:
- <200 g transceiver mass + 2 antennas of 60 g each for omni-directional coverage
- 1 W receive and 3 W transmit electrical power consumption
- Full duplex
- Data rate (two-way) of up to 1 Mbps with main AIM spacecraft
- Total data volume of up to 1 Gbit allocated for the whole mission
- 3 months maximum data relay duration by AIM
- Separation conditions: 0.5-2 m/s velocity provided by deployer along 3-axis vector provided by main spacecraft