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First System Engineering approach

Andrea Messidoro

on 7 May 2010

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Transcript of QB50

Mission Architecture Launch Segment Mission Environment Communications Architecture S/C Bus S/C Payload Scientific (fixed) ---> Requirements Applications (flexible) Reference List Stakeholders Duties of SE group QB50 has the scientific objective to study in situ the temporal and spatial variations of a number of key constituents and parameters in the lower thermosphere with a network of 50 double CubeSats, separated by a few hundred kilometers and carrying identical sensors. Our task: within QB50, TU Delft shall contribute two CubeSats each equipped with a propulsion system to enhance the mission return in science and technology. Mission Statement duration (3 months) Top-level Mission Requirements altitude range (90-330 km) separation between CubeSats (200-400 km) total network size (10000-20000 km) launch vehicle SHTIL 2.1 on QB50 the CubeSats are the primary payload Top-level CubeSat Requirements equipped with propulsion system [1] [1] dimensions (10x10x10 cm) [1] paper "QB50, an international network of 50 double CubeSats for multi-point, in-situ measurements in the lower thermosphere and for re-entry research" by J. Muylaert - 1st QB50 Workshop (November 2009), von Karman Institute for Fluid Dynamics (VKI), Sint-Genesius-Rode (Brussels), Belgium weight (max. 2 kg) key technology (COTS) cost (low - 50-100 kEuro) [2] [3] [3] [12] [2] slides "Introduction v 1.2" by Professor Dr. E. Gill - course of Micro-Satellite Engineering (19 January 2010), TU Delft (SSE), Delft, Netherlands [3] QB50 website by VKI: http://www.vki.ac.be/QB50/project.php Pico-Satellite [2] 90-330 km: Lower Thermosphere Characteristics (Constraints) ---> Requirements on S/C Additional Informations domination of molecular diffusion [4] UV and X-rays radiations cause ioni-zation [5] ISS orbits between 270-460 km [4] Turbopause (Wikipedia): http://en.wikipedia.org/wiki/Turbosphere [5] ISS (Wikipedia): http://en.wikipedia.org/wiki/International_Space_Station [5] aurora phenomena [4] highly rarefied environment [1] Temperature range 120-1500 C (increasing with the altitude) ---> but 0 C perceived [4] Remember: Studying the environment in terms
of measurements and data is part of the
QB50 mission statement remote-sensing by ground based lidars and radars up to 105 km
(data on http://www.vki.ac.be/QB50/download/workshop/papers_17nov/luebken.pdf - QB50 Workshop 2009) Electrically charged particles in the environment (from Solar Activity, GCRs):
1. enable radio waves to bounce off and be received beyond the horizon
2. Single Event Effects on electronics devices (SEU, SEL, SEB) [4] more information on http://www.cubesat.org/ atmospheric tide (<120 km) [4] transition molecular-atomic athmos-phere, above 200 km atomic species (O, He, N,H ) [6] paper "The physics and chemistry of the lower thermosphere" by G. Brasseur - 1st QB50 Workshop (November 2009), von Karman Institute for Fluid Dynamics (VKI), Sint-Genesius-Rode (Brussels), Belgium [6] sounding rockets missions in the MLT Region
(data on http://www.vki.ac.be/QB50/download/workshop/papers_18nov/luebken.pdf - QB50 Workshop 2009) high variability in density, pressure and temperature due to to local time / season, and solar / geomag-netic activity Drag ---> shortens orbit lifetimes ----> Drag Coeficient = 2.2 [-] and Drag Area: 0.015 [m2]
Changes in atmospheric density cause changes in satellite low eart orbits (LEO).
Uncertainty in drag (from density) is primary uncertainty in orbit determination [7] paper "Remote-sensing observations of the MLT region by Earth observation satellites" by M. Drinkwater - 1st QB50 Workshop (November 2009), von Karman Institute for Fluid Dynamics (VKI), Sint-Genesius-Rode (Brussels), Belgium [7] [7] [7] Geomagnetic field: it can combine with the field of the electromagnetic instruments in the CubeSats
SWARM mission results at http://www.esa.int/esaLP/ESA3QZJE43D_LPswarm_0.html [8] [8] slides "Space Environment" by S. Corpino - course of Space Systems (December 2008), Politecnico di Torino, Torino, Italy ESA
VKI (contact: Cem O. Asma, asma@vki.ac.be)
Prof. Gill as chairman of SSE at TU Delft and as lecturer of Micro-Satellite Engineering course
Universities in the CubeSats community taking part in the QB50 project (e.g. Stanford University, University of Würzburg, San Jose University, University of Tokyo, Ecole Polytechnique Fédérale de Lausanne)
Scientific research centers ( Leibniz-Institute of Atmospheric Physics - Kühlungsborn, Athena Research Center, NASA/Ames Research Center ) Chemical Effects ---> atomic oxygen attack (oxidation) ---> it degrades the S/C surfaces, weakens
components, change their thermal characteristics and degrades sensors Radiation ---> 1. heating on exposed surfaces
2. contamination and solar UV degradation and damage to surfaces
3. solar pressure (Radiation Pressure Coefficient: 1 [-])
---> effect on pointing and attitude MMOD [8] [8] [8] [8] 1. Connecting the 4 groups in terms of work, informations and results.

2. Having a general idea (SE view) of the 2 CubeSats for QB50 project in all its development

3. Mantaining the interface and the contacts with the QB50 mission stakeholders
- 10 May 2010: meeting with PhD student Cem O. Asma at VKI

4. Taking care of the final report structure and review Idea Science Unit the CubeSats will be below the Van Allen's radiation belts, which is very important because they are supposed
to use low-cost COTS components [1] Functional Unit it basically refers to the functional unit:
- Structure and Mechanism Subsytem (Group 3)
- Power Subsystem (Group 3)
- Command and Data Handling Subsystem (Group 2)
- Thermal Control Subsytem (Group 3)
- Communications Subsystem - TT&C and GN (Group 2)

Suggestions in the lecture about Bus Technology [9] it basically refers to the science unit:

- Sensors to be selected by a external Working Group (t.b.d.)
---> we can provide our proposals considering the top level mission requirements

- Standard sensors for all CubeSats (t.b.d.)

- Lower Thermosphere Measurements (atmospheric data providing temporal and
spatial variations):

1. Atmospheric Density "Broglio Drag Balance" concept of UniRoma, La Sapienza

2. Atomic Concentration (N and O) using spectroscopic techniques (big, heavy and consuming)
- CanX-2 (UniToronto): Atmospheric Spectrometer by Dr. Brendan Quine of York University
- Delfi n3xT (TU Delft): The Multifunctional Particle Spectrometer produced by cosine Research

3. Magnetic Field based on a Wheatstone Resistor Bridge
- 3-axis magnetic sensor Honeywell, HMC2003 (datasheet http://datasheet.octopart.com/HMC2003-Honeywell-datasheet-90458.pdf)

4. Radiation based on Silicon Drift Detector
- DLR Phoenix GPS Receiver (http://www.weblab.dlr.de/rbrt/GpsNav/Phoenix/Phoenix.html)
- AAUSat II (Aalborg, DK): Experimental Gamma Detector
(http://aausatii.space.aau.dk/homepage/index.php?language=en&page=pl/pl) it basically refers to the functional unit (Group 4):

- Propulsion system

- Attitude and Orbit control system ---> strictly correlated with GN and Orbit section
atmospheric models and drag coeficient from Orbital Dynamics Working Group (2010)
---> for the moment assumptions and proposals in the "training program report about QB50" by J. Naviaux
also suggestions in http://www.vki.ac.be/QB50/download/workshop/papers_18nov/schmidt.pdf)

- Optional technology: Re-entry control (paragraph 4 in the "training program report about QB50" by J. Naviaux [12]), Formation Flying...

- Additional Science pakage (suggestions in [7]) [1] [1] [1] multi-point, in situ measurements of the neutral components in the lower thermosphere Examples for sensors/instruments [1] The von Karman Institute for Fluid Dynamics (VKI) will provide:

Identification of the funding sources for the launch vehicle,
Management of the interface to the launch vehicle authorities, including
management of the launch campaign,
Support for the selection of the standardized sensors for lower thermosphere and
re-entry research to be used on board the CubeSats,
Detailed orbital dynamics calculations, using a variety of trajectory simulation
software tools and atmospheric models, and comparison of model predictions with
actual CubeSat re-entry data,
Provision of a CubeSat to the QB50 Network (Re-EntSat),
Management and funding of the QB50 Data Processing Centre,
Organization of the annual QB50 Science Workshops,
Installation and management of the VKI Ground Station
Maintenance of the QB50 website: http://www.vki.ac.be/QB50 Sensor Selection Working Group (SSWG) (15 members)

Defines exactly what should be measured
Sensor selection (starting with a list of ~20 sensors and then gradually narrowing that down to 3 -5 sensors, including scientific priority, volume, mass, power and data rate requirements)
- A few CubeSat PIs
- A few atmospheric physicists/chemists
- Experts for in-situ instruments for atmospheric research
- D/EOP representatives
Meets 4 times in 2010 Orbital Dynamics Working Group (ODWG) (15 members)

Defines deployment sequence and speed
Defines initial orbital altitude (which determines the lifetime)
Compares simulated trajectories with actual trajectories
- Atmospheric modeling experts
- Trajectory simulation software experts
- Orbital dynamics experts from D/OPS and D/TEC
Meets 3 – 4 times per year (starting March 2010 until early 2014) QB50 – Tentative Schedule

17-18 Nov 2009 Science Workshop at VKI
Feb - June 2010 Individual meetings with all CubeSat teams who submitted an LoI
March 2010 Meetings of the SSWG and ODWG
June 2010 Meetings of the SSWG and ODWG
14 Sep 2010 Parallel meetings of the SSWG, ODWG and FAWG
15 Sep 2010 Second annual QB50 Workshop at VKI
16 Sep 2010 QB50 Project Kick-Off meeting
16 Sep 2010 Meeting of the QB50 Steering Group
17 Sep 2010 Issue by VKI of the Call for Proposals for QB50 CubeSats
11 Oct 2010 Deadline for submission of CubeSat proposals to VKI, including letters of funding
11 - 22 Oct 2010 Proposal clarification period
25 Oct - 4 Nov 2010 Evaluation of proposals by VKI and selection of 50 CubeSats plus 5 backup CubeSats
5 Nov 2010 Notification on selection to CubeSat PIs
Dec 2010 Meeting of the SSWG, final selection of the standardized sensors [1] [1] [1] [1] Double CubeSat (10 x 10 x 20 cm3) FIPEX sensor for measurement of atomic oxygen
(file http://www.vki.ac.be/QB50/download/workshop/papers_18nov/fasoulas.pdf)
Atmospheric density measurements
Miniaturized neutral mass spectrometer
Thermocouples / Thermistor / Resistance temperatures detectors
GPS [1] [9] slides "Payload&Bus technology_Bus" by J. Bouwmeester - course of Micro-Satellite Engineering (9 February 2010), TU Delft (SSE), Delft, Netherlands [1] [1] [1] it has the function of providing tracking, telemetry and controls (TT&C) or other data communication between the space segment and all users on the ground

- downlink using the Global Educational Network for
Satellite Operations (GENSO) ( http://www.genso.org/)

- uplink (Commands) needed considering that the Cube-
Sats have propulsion system [10] Additional Informations - A low-Earth orbit allows high data rates because of the short communication
distances involved ---> estimation of Data Rate for Link Design (Group 3) later on
in the discussion.
- Information on Communications Architecture in [11] [1] [1] [10] lecture notes of the course Space Engineering & Technology I by Prof.ir. B.A.C. Ambrosius (August 2002), TU Delft (SSE), Delft, Netherlands Communication Requirements Data are: - telemetry (D) to users (stakeholders and amateurs)
- payload data (D) to users (stakeholders)
- commands (U) from t.b.d.
Quantity of data per time TBD considering C&DHS, Orbit and Scientific Payload
Access time and coverage TBD considering Orbit and Ground Segment
Transmission delay due to
- Ionosphere (function of the frequency)
- Rain Attenuation (function of the frequency and the elevation)
Frequency band TBD [11] [11] Space Mission Analysis and Design by J.R. Wertz (SMAD)
[12] "Training program report about QB50" by J. Naviaux (January 2010)
[13] Space Systems Engineering, 4th Yr. course Msc TUDelft, Lecture 1 - Introduction, E. Gill
[14] US Military Standard (MIL-STD) 499B
[15] ESA Standard ECSS-P-001
[16] Reader Space I - Part I, 1st Yr. course Bsc TUDelft, B.A.C Ambrosius
[17] SHTIL User Guide, Makeyev Design Bureau, Issue 1.1, January 2002
[18] Orbital deployers for CubeSats and orbital dynamics, A. Bonnema, ISIS, QB50 Workshop, 17/18 Nov 2009
[19] GENSO, the Global Educational Network for Satellite Operations, P. Beavis , QB50 Workshop 18 Nov 2009 possible athmospheric density model and solar activity prediction in the "training program report about QB50" by J. Naviaux [12] Concerns the trajectory or path of the Spacecraft and provides acces and coverage to and or from the object to the ground. Seperation distance between CubeSats is 200 to 400 [km]
With 50 CubeSats this would mean a total network size of
10.000 to 20.000 [km]
Right Ascension of the Ascending Node (RAAN) can be between 0 to 360 [deg]
Estimated deployment sequence time is 3 [h]
Estimated deployment velocity is 1.5 to 2.5 [m/s]
Deployment system, direction and sequence is TBD, for more information about several Deployment Systems
See Reference [18] This segment is about the launch facility, the launch vehicle and any upper stage to place the spacecraft in orbit as well as interfaces, payload fairing and associated ground equipment. The function of this segment is to provide trans-portation from the ground to a location in space. Launch profile
Maximum payload mass versus altitude
Accuracy payload injection
Loads during launch
Payload and rocket interference
Ground operations Very challinging since this LV is based on the SHTIL misile so large accelerations are expected Requirements
A singular documented need of what a particular product or service should be or do
Identify accomplishment levels needed to achieve specific objectives
That which is called for or is demanded: a condition which must be complied with

'External' Limitations like the Solar Flux or the dimensions of the fairing if first the LV is chosen and then the S/C is designed The ground segment concerns the fixed and mobile ground stations around the globe connected by various data links. It provides ground monitoring, command and communication services to the mission. Kyushu University, Fukuoka, Japan: 130.422 longitude, 33.615lattitude
Aalborg University, Aalborg, Denmark, 9.985 longitude, 57.015 latitude
University of Surrey, Guilford, UK: -0.586 longitude, 51.242 latitude
International Space University, Strasbourg, France: 7.733 longitude, 48.521 latitude
Politecnico di Torino, Turin, Italy: 7.661 longitude, 45.062 latitude
California Polytechnic State University, San Luis Obispo, USA: -120.665 long., 35.302 lat.
G3VZV, Graham Shirville, UK: N.A.
G4DPZ, David Johnson, UK: N.A.
Grounds stations & their geographic location
Estimated required ground stations needed for optimized coverage is about 100
Optimize coverage means one satellite flying over at a time
Expansion 'ground stations' possible through radio amateurs Main Characteristics Additional Data Launch vehicle is the SHTIL 2.1
Launch site is at the Plesetsk Cosmodrome
The Geographic Location is 62.8 [deg] North and 40.1 [deg] Easth
Launch date is planned during the 12th Solar cycle, July 2013
Deployment phase is above the Pacific
Geographic location deployment phase is 53 [deg] North and 170.2 [deg] East Ground Segment Main Characteristics Operator: GENSO (Global Educational Network for Satellite Operations)
Tasks of GENSO

Amount of ground stations: 8
Coverage: 50 to 1000 [s]
Passing: 15 % of a circular orbit
Footprint: 5 to 1 % of Earth surface

Ground communication At initial altitude (around 300 [km]) it is about 5 % and at final altitude (around 90 [km] it is about 1% Additional Data Orbit & Constellation Orbit type is circular so the eccentricity must be about zero
The inclination angle is 79 [deg]
Initial altitude is about 330 [km]
Final altitude is about 90 [km]
For orbital velocity see SMAD
Lifetime is about 3 [months] Main Characteristics Additional Data Definitions Functional Flow Diagram Launch Operate
CubeSate Perform
Main Task End Life Top Level Launch Second Level Operate CubeSat Perform
Main Task Insert PL
into LEO Deploy all CubeSats Deploy
Power Mech. Provide Power Analyze Lower TS Test Propulsion S. Analyze Re-Entry Comm.
with Earth Space Segment QB50 [12] [12] [1] Frequency Allocation Working Group (FAWG) (5 members)

Selection of frequency band (UHF / VHF or S–band)
Ground station coverage / GENSO interface
Preparation of request for frequency allocation
Composition (possible members: G. Shirville, G. Auvray, G. Bertels, K. Ruf, a GENSO representative) [13] [14] [15] [16] [16] [16] [9] [9] [9] [9] [9] [9] [17] [9] [12] [12] [12] [12] [12] [17] [17] [17] [17] [17] [12] [18] [9] [9] [18] [18] Groundstations GENSO [18] [18] [18] [18] [19] [19] [19] [18] [19] Report Arial 11
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