Session 5: Focused Discussions

1
Session 5 Focused DiscussionsMissions in
DefinitionMars Telecommunications Orbiter 2009

• Chad Edwards
• Mars Chief Telecommunications Engineer
• Roger Gibbs
• MTO Project Manager

2
Mars Telecommunications Overview

• Communications is a key challenge for in situ
  exploration
• Earth-Mars link is 108 times further than a GEO
  comsat link

3
1- Surface Operations Relay Support

• Increased Connectivity
• Multiple comm contacts per sol
• Visibility to night side and to poles (when Earth
  out of view)
• Supports complex in situ operations

• Increased Data Return
• Low-gain DTE 3 kb/sol
• MER-class DTE 30 Mb/sol
• ODY-class relay 100 Mb/sol
• MTO-class relay 1-10 Gb/sol
• Enables high-resolution in situ science
  instruments

• Increased Energy Efficiency
• Low-gain DTE 500 W-hr/Mb
• MER-class DTE 5 W-hr/Mb
• Relay lt0.1 W-h/Mb
• Enables small scout-class mission concepts
  increases energy available for science

4
Relay Performance for MER

• The MER mission has clearly demonstrated the
  value of relay telecommunicaitons
• Over 75 Gigabits of data have been returned from
  Spirit and Opportunity (as of 3 Nov, 2004)
• 96 of data return has been via UHF relay through
  ODY and MGS

Cohokia Panorama image, acquired by the Spirit
Pancam instrument (588 Mbit compressed data
volume)
5
2- Critical Event Communications

• In response to loss of Mars Polar Lander (98)
  during EDL (w/out any communications), MEP
  established a policy to require capture of
  engineering telemetry during future mission
  critical events
• Provides critical feed-forward information in the
  event of a mission anomaly
• Requires communications link availability under
  specific spatial and temporal constraints
• Data rate driven by bandwidth, complexity of
  engineering systems

6
Critical Event Communications ChallengeAt the
Right Place, Right Time

• Direct-to-Earth communications provides coverage
  of half of planet, but at extremely low (1 bps)
  data rates
• Science orbiters can support high-rate telemetry,
  but with extremely limited visibility
• 400 km, polar orbit
• Constrained orbit node
• Higher altitude telesat can provide greatly
  increased coverage

7
Program Strategy

• Provide evolutionary infrastructure growth at low
  cost by flying standardized proximity link
  payload on every Mars science orbiter
• MGS, ODY, MRO science orbiters
• Interoperability with international assets
  (e.g., Mars Express)
• Communications capabilities largely defined
  (i.e., constrained) by science-driven orbit
  characteristics
• Establish revolutionary infrastructure
  capabilities by deploying first dedicated Mars
  relay satellite 2009 Mars Telecommunications
  Orbiter
• Orbit selected to optimize communications
  figures-of-merit

8
Telecommunications Capability
9
MTO as Technology Development Platform
In addition to its primary objective of serving
as the Mars telecommunications satellite, MTO
also provides a platform for two technology
experiments - Optical communications from deep
space - Deep space autonomous rendezvous
10
Mars Laser Communication Demonstration

• Flight Terminal
• 5W Laser
• Data rate 1 to 30 Mbps
• Inertial / beacon pointing
• Command at 10 bps

• Ground Terminal
• 5m mirror at Mt Palomar
• 4 element array (80 cm each)
• Transmit a beacon and uplink commands
• Daylight operations

11
Rendezvous and Autonomous Navigation
(RAN)Technology Demonstration
RAN is composed of two linked elements

• Rendezvous
• Perform a rendezvous demonstration with an
  Orbiting Sample Canister.
• Provides critical feed-forward to Mars Sample
  Return Mission.

• AutoNav
• Demonstrate autonomous Orbital Nav using Mars
  landmarks, Phobos and Deimos.
• Supports Mars unmanned and manned safe and
  low-cost operational infrastructure.

12
MTO Status

• Mission Concept Review successfully completed May
  2004
• Contractor selection in progress
• Industry day conducted June 2004
• Released Draft RFP, Final RFP
• Proposals due December 3, 2004
• Contractor selection, factfinding, negotiation
  and on contract May 2005
• MLCD completed Mission Concept Review and System
  Requirements Review Flight Terminal Peer Review
  PDR scheduled for May 2005.
• Preliminary Mission System Review scheduled for
  September 2005.
• Launch in 2009 requires significant coordination
  with MSL.
• Design life of 10 years