AAE 450 – Spacecraft Design

1Zade Shaw

ARV, ELV and Total CommunicationsZade Shaw

8 February 2005Communications GroupDocking Ad Hoc CommitteeD&C and Propulsions InterfaceCommunications Liaison for the CTV and MLV

AAE 450 – Spacecraft Design

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Problem: Need ARV and ELV Comm.

http://www.decaturco.k12.in.us/space/spaceimages/sat5_as500f.jpg

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Comm. Totals for Project Legend

Vol(m3)/Dia(m) Mass (kg) Power (kW)

CTV / MOS - Earth

9 – 20 m 450 - 1000 6–25 10m re

2–6 20m re

CTV – MHV 1 m 150 0.2

CTV – MLV 2 m 200 0.4

ARV 1 m3 200 0.9

ELV 1 m3 100 0.1

MLV 0.5 m 100 0.4

MHV 2 m 200 0.2

AAE 450 – Spacecraft Design

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ELV Communications Plot

AAE 450 – Spacecraft Design

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CTV / MOS Communications Plot

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General References Larson, Wiley J., & Pranke, Linda K. Human Spaceflight: Mission

Analysis and Design, (pgs. 869-906). New York, US: McGraw Hill.

Larson, Wiley J., & Wertz, James R. (1999). Space Mission Analysis and Design, (pgs. 533-586). El Segundo, US: : Microcosm Press.

http://deepspace.jpl.nasa.gov/dsn/index.html http://eis.jpl.nasa.gov/deepspace/dsndocs/810-005/ http://www.fiber-optics.info/articles/dtv-hdtv.htm http://www.triadtwcable.com/cableserv/images/SAHDTVFAQs.pd

f Jeri Metzger’s presentation was utilized for the picture on slide 2

of presentation 1

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Antenna Array References http://www.emsstg.com/pdf/sar2.pdf http://tmo.jpl.nasa.gov/progress_report/42-

158/158D.pdf

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Data Compression References http://www.data-compression.com/index.shtml http://www.cs.bris.ac.uk/Research/Digitalmedia/vidcoding.html http://www.informit.com/articles/article.asp?p=29249&seqNum=2 http://www.computerworld.com/news/1999/story/

0,11280,43440,00.html http://www.bbc.co.uk/rd/pubs/papers/paper_14/paper_14.shtml http://www.extremetech.com/

article2/0%2C1558%2C53957%2C00.asp http://www.engineerlive.com/cgi-bin/articles.pl?

action=display&id=2219&subsection=405&t=1&section=11

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Deployable (first) and HDTV References http://image.gsfc.nasa.gov/press_release/

image_pr_20000526.html http://csperkins.org/hdtv/

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Link BudgetZade Shaw

25 January 2005Communications TeamD&C and Propulsions InterfaceDocking Ad Hoc CommitteeCommunications Lead for HAB

AAE 450 – Spacecraft Design

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The Problem: Video and Vast distances

http://deepspace.jpl.nasa.gov/dsn/gallery/goldstone.html

• HDTV Data Rate: 80 Mbps

• Distance (long): 3.78 x 108 km

• Key Issues:

• Radio Band Selection

• Signal to Noise Ratio

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Solution: Size & Power Required Ka Band: high data transfer, low atmospheric loss Ideal S/N = 3 dB Transmission:

115 kW 12 m Dia. 1500 kg 2 m3 (internal)

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Calculations (for slide 2) The 80 Mbps number comes from research (see

references). It was discovered that it would take about 20 Mbps / HDTV and it was assumed that we would use 2 such connections each way. Hence, 80 Mbps.

The calculation of the 3.78*10^8 km was done in the Matlab script in the following way: am = 2.27936636e8; semi-major axis Mars, km ae = 1.49597807e8; semi-major axis Earth, km S = am + ae; Earth-Mars Distance, km

AAE 450 – Spacecraft Design

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Calculations (for Slide 3) Ka band and ideal S/N were chosen based on research

(see references) The power, diameter and mass were calculated using the

attached MATLAB code. The primary sources for building this code were Professor Filmer’s lecture material and Human Spaceflight (see references).

The mass was calculated assuming a thin shelled (1cm thickness) hemisphere shape for the antenna and a material density for Aluminum 6061-T6, which was the material used for last year’s HOMER.

The internal volume of 2 cubic meters was an estimated based on last year’s HOMER value of 1.3 cubic meters.