X ray missions delta axsio redux
This presentation is the property of its rightful owner.
Sponsored Links
1 / 28

X-ray Missions Delta: AXSIO Redux PowerPoint PPT Presentation


  • 85 Views
  • Uploaded on
  • Presentation posted in: General

X-ray Missions Delta: AXSIO Redux. Communications Ron Vento Blake Lorenz 30 April – 1 May, 2012. Topics. Overview Change implications Functional Configuration Driving Requirements and Assumptions Mission Orientation Data Volume Data rates & Storage

Download Presentation

X-ray Missions Delta: AXSIO Redux

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


X ray missions delta axsio redux

X-ray Missions Delta:AXSIO Redux

Communications

Ron Vento Blake Lorenz

30 April – 1 May, 2012


Topics

Topics

  • Overview

  • Change implications

  • Functional Configuration

  • Driving Requirements and Assumptions

  • Mission Orientation

  • Data Volume

  • Data rates & Storage

  • Selected Configuration and Rationale

  • Signal Margin Summary

  • Cost/Mass/Power Summary

  • X-ray AXSIO antenna parameters

  • Backup


Overview

Overview

  • Ka-Band for science and data dumps via DSN 34 meter

    • Data dumps at 20 Mbps

    • One 20minute contact per day require to dump data.

    • Two peak views back to back could be downlinked in one 2.5 hour contact

    • Mission typical nominal plus peak data averages ~ 25 minutes downlink time

  • S-Band TT&C via HGA to DSN 34 meter

    • 2 kbps command

    • 8 kbps telemetry

  • S-Band TT&C via Omni to DSN 34 meter

    • 1 kbps command

    • 2 kbps telemetry

  • Ranging for orbit determination

  • S-Band thru TDRSS for launch and LEO critical events

    • 1 kbps command

    • 1 kbps telemetry


Change implications

Change implications

Even though the data rates have increased, there would be no significant saving by having a larger or smaller diameter High Gain Antenna

(for a lower or higher data rate).


Functional configuration

Functional Configuration

decrypter

S

S/Ka-band

Transponder

Hybrid

Diplexer

S

S-Band omnis

PA

switch

K

S

decrypter

S

C&DH

PA

S

Diplexer

switch

S/Ka-band

Transponder

Hybrid

S

switch

ISOLATOR

Ka-band

TWTA

SWITCH

S / Ka

HGA

Triplexer

K

Ka-band

TWTA


Functional configuration1

Functional Configuration

1 kbps tlm1 kbps Command (launch & LEO)

TDRS

Ka-band: 20 Mbps telemetry

S-band: 8 kbps Tlm 2 kbps command,& Ranging

34M

MOCC

White Sands complex

DSN

Command

Command

Housekeeping

Science & Hskpg


Driving requirements assumptions

Driving Requirements & Assumptions

  • Launch: ~ 15 June 2022

  • Mission Life: 3 years design (size expendable for 5 years)

  • Mission Class: B

  • Nominal Orbit: L2 Lissajous

  • Stellar pointing

  • Orbit determination via DSN ranging

  • Ranging required

    • One 60 minute period/day during transfer orbit

    • One 30 minute period/day when on orbit

    • Absolute timing requirement of 100 ɥs at L2 (handled by Avionics with Atomic clock)

  • Latency: 72 hours for nominal data

  • Telemetry BER: 10-6

  • Nominal Instrument data rate: 205 kbps

  • Peak science collection rates up to 12 hours at 3.085 Mbps forbright object observations at random intervals

    • (assume up to two 6 hour peak observation in a month)


L 2 orbit

L-2 Orbit

800,000 km amplitude L-2 Orbit with 180 day period

L-2

Earth-Sun angle: 7 to 34º

Lunar Orbit

L-2 Transfer

Trajectory

E

Earth- L2 Distance: 1.5 x 106 km

To

Sun

Courtesy - JWST

Max Range: 1.8 x 106 km

  • L2 800,000 km semi-major axis halo orbit

  • 0% solar or lunar obscuration throughout 10 years

  • Essentially the same orbit as JWST


Data rate and storage analysis

Data Rate and Storage Analysis

  • Storage Size Requirement (from Project)

    48 hours including 12 hours of peak rate and 36 hours of average rate (this is called 48-hour-peak-volume)

    +

    up to 1 day of missed passes (ie., an additional 24 hrs of avg data rate)

    ____________________________________________________________________________

    = A TOTAL of 12 hours peak plus 60 hours of avg data

    (Assumed 100% efficiency for this 72 hour storage sizing)


Data volume

Data Volume


Data storage volume

Data Storage Volume


Data storage volume1

Data Storage Volume


Selected configuration rationale ka band

Selected Configuration & RationaleKa-Band

  • Ka-band used for data dumps

  • Two DSN S/Ka-Band transponders

  • Two 10 watt Ka-Band TWTAs

  • Data will be LDPC rate ½ encoded

  • QPSK modulation will be used for Ka-band (Residual carrier for S-band when ranging)

  • Gimbaled 0.5 M dual frequency high-gain antenna (On the Earth pointed axis)

  • Transmit data rate of 20Mbps to DSN 34 meter

    • Multiple rates can be included if lower or higher rates needed

  • A 30 minute contact is required every day for ranging.

  • 20 minutes required to transmit nominal data simultaneous with the 30 min ranging contact

  • Two 6 hour peak observations would require 2.5 hours extra time to downlink the data

    • 3 days for 70 minutes would downlink 12 hours peak data in 3 days

    • ~17 days for 30 minutes would downlink 12 hours peak data

  • 95% rain availability is assumed

  • Redundancy except for the antenna systems


Selected configuration rationale s band

Selected Configuration & RationaleS-Band

  • S/Ka-band communications using DSN 34 m

  • S-Band for TT&C

  • 5 watts RF using 5 watt power amplifiers via omnis or the HGA

  • Use omnis

    • 2 kbps telemetry

    • 1 kbps command

  • Use HGA

    • 8 kbps telemetry (rates up to 250 kbps are achievable)

    • 2 kbps command

  • Use TDRSS for launch and LEO critical events

    • 1 kbps command

    • 1 kbps telemetry

  • Ranging: One hour contact per day during transfer orbit and one 30 minute contact per day when on orbit, alternating between north and south hemisphere locations

    • Avionics is implementing an atomic click to accommodate the strict timing requirement


Link margin summary

Link Margin Summary

TDRSS guarantees support with a margin of >0 dB

S-Band return links use residual carrier (worse case) for ranging.


Component summary

Component Summary


X ray axsio ka s band antenna

X-ray AXSIO Ka- / S-band Antenna


Dsn support

DSN Support

  • Launch and early orbit

    • Continuous tracking for the first 48 hours

  • DSN 34M/Transfer orbit

    • Two 30 minute contacts/day

    • 24 hour support before and after each mid course corrections (Two corrections planned)

    • 100 days to orbit

    • Orbit insertion

  • DSN 34M/ Mission orbit

    • One 30 minute contact /day

    • Twice a month a 2.0 hour contact (for peak rate data or contingency if needed)

  • Pre-pass time: 45 minutes

  • Post-pass time: 15 minutes


Total costs

Total Costs

  • Total mission costs for 3 years: $14.0 M Total mission costs for 5 years: $15.5 M (Excludes timing system and FTEs)

  • Launch and early orbit: $155 k

    • TDRSS costs: $55 k

      • 2 hours SSA support: $15.2 k

      • Documentation: $40 k

    • DSN 48 hours support: $100 k

  • DSN 34M/Transfer orbit: $602 k

    • 0ne hour contact/day: $345.3 k

      • 100 days to orbit

    • Two mid course corrections: $171 k

    • Orbit insertion: $85.6 k

  • DSN 34M/ Mission orbit: $2.77 M/3 years DSN 34M/ Mission orbit: $4.67 M/5 years

    • One 30 minute contact /day: $2.77M/3yr, $4.63M/5yr ($925 K/year)

    • Two 2 hour contacts/month: $204k/3yr, $340k/5yr ($68 k/year)

  • Spacecraft cost: $9.76 M


X ray missions delta axsio redux

.

Back-up Slides

Ka-band (HGA) to 34 meter (at 10 Mbps)

S-band (HGA) to 34 meter

S-band 34 meter to HGA

S-band (omni) to 34 meter

S-band 34 meter to omni

TDRSS return link

TDRSS forward link


Ka band hga to 34m bwg

Ka-Band (HGA) to 34m BWG


S band hga to 34m bwg

S-Band (HGA) to 34M BWG


S band 34 m to s c hga

S-Band 34 M to S/C HGA


S band 34 m to s c omni

S-Band 34 M to S/C omni


S band s c omni to 34 m

S-Band S/C omni to 34 M


S band s c omni to tdrss

S-Band S/C omni to TDRSS


S band tdrss to s c omni

S-Band TDRSS to S/C OMNI


Acronyms

Acronyms


  • Login